of Novel Pore-Graded Gas Diffusion Layers for High-Performance and Cost-Effective Proton Exchange Membrane Electrolyzers. *Energy Environ. Sci.* **2017**, *10* (12), 2521–2533.

(335) Mo, J.; Kang, Z.; Yang, G.; Retterer, S. T.; Cullen, D. A.; Toops, T. J.; Green, J. B.; Zhang, F.-Y. Thin Liquid/Gas Diffusion Layers for High-Efficiency Hydrogen Production from Water Splitting. *Appl. Energy* **2016**, *177*, 817–822.

(336) Razmjooei, F.; Morawietz, T.; Taghizadeh, E.; Hadjixenophontos, E.; Mues, L.; Gerle, M.; Wood, B. D.; Harms, C.; Gago, A. S.; Ansar, S. A.; Friedrich, K. A. Increasing the Performance of an Anion-Exchange Membrane Electrolyzer Operating in Pure Water with a Nickel-Based Microporous Layer. *Joule* **2021**, *5* (7), 1776–1799.

(337) Schuler, T.; Ciccone, J. M.; Krentscher, B.; Marone, F.; Peter, C.; Schmidt, T. J.; Büchi, F. N. Hierarchically Structured Porous Transport Layers for Polymer Electrolyte Water Electrolysis. *Adv. Energy Mater.* **2020**, *10* (2), 1903216.

(338) Frensch, S. H.; Olesen, A. C.; Araya, S. S.; Kær, S. K. Model-Supported Characterization of a PEM Water Electrolysis Cell for the Effect of Compression. *Electrochim. Acta* **2018**, *263*, 228–236.

(339) Doan, T. L.; Lee, H. E.; Shah, S. S. H.; Kim, M.; Kim, C.; Cho, H.; Kim, T. A Review of the Porous Transport Layer in Polymer Electrolyte Membrane Water Electrolysis. *Int. J. Energy Res.* **2021**, *45* (10), 14207–14220.

(340) Chen, Y. X.; Lavacchi, A.; Miller, H. A.; Bevilacqua, M.; Filippi, J.; Innocenti, M.; Marchionni, A.; Oberhauser, W.; Wang, L.; Vizza, F. Nanotechnology Makes Biomass Electrolysis More Energy Efficient than Water Electrolysis. *Nat. Commun.* **2014**, *5* (1), 4036.

(341) Lavacchi, A.; Bellini, M.; Berretti, E.; Chen, Y.; Marchionni, A.; Miller, H. A.; Vizza, F. Titanium Dioxide Nanomaterials in Electrocatalysis for Energy. *Curr. Opin Electrochem* **2021**, *28*, 100720.

(342) Bellini, M.; Berretti, E.; Innocenti, M.; Magherini, G.; Pagliaro, M. V.; Poggini, L.; Miller, H. A.; Lavacchi, A.; Vizza, F. 3D Titania Nanotube Array Support for Water Electrolysis Palladium Catalysts. *Electrochim. Acta* **2021**, *383*, 138338.

(343) Cook, W. G.; Olive, R. P. Pourbaix Diagrams for the Nickel-Water System Extended to High-Subcritical and Low-Supercritical Conditions. *Corros. Sci.* **2012**, *58*, 284–290.

(344) Li, K.; Yu, S.; Li, D.; Ding, L.; Wang, W.; Xie, Z.; Park, E. J.; Fujimoto, C.; Cullen, D. A.; Kim, Y. S.; Zhang, F.-Y. Engineered Thin Diffusion Layers for Anion-Exchange Membrane Electrolyzer Cells with Outstanding Performance. *ACS Appl. Mater. Interfaces* **2021**, *13* (43), 50957–50964.

(345) ASTM. ASTM D1193-06(2018) - Standard Specification for Reagent Water; 2018.

(346) Simoes, S. G.; Catarino, J.; Picado, A.; Lopes, T. F.; di Berardino, S.; Amorim, F.; Gírio, F.; Rangel, C. M.; Ponce de Leão, T. Water Availability and Water Usage Solutions for Electrolysis in Hydrogen Production. *J. Clean Prod* **2021**, *315*, 128124.

(347) Dresp, S.; Dionigi, F.; Loos, S.; Ferreira de Araujo, J.; Spöri, C.; Gliech, M.; Dau, H.; Strasser, P. Direct Electrolytic Splitting of Seawater: Activity, Selectivity, Degradation, and Recovery Studied from the Molecular Catalyst Structure to the Electrolyzer Cell Level. *Adv. Energy Mater.* **2018**, *8* (22), 1800338.

(348) Dresp, S.; Dionigi, F.; Klingenhof, M.; Strasser, P. Direct Electrolytic Splitting of Seawater: Opportunities and Challenges. *ACS Energy Lett.* **2019**, *4* (4), 933–942.

(349) Tong, W.; Forster, M.; Dionigi, F.; Dresp, S.; Sadeghi Erami, R.; Strasser, P.; Cowan, A. J.; Farràs, P. Electrolysis of Low-Grade and Saline Surface Water. *Nat. Energy* **2020**, *5* (5), 367–377.

(350) Naito, T.; Shinagawa, T.; Nishimoto, T.; Takanabe, K. Water Electrolysis in Saturated Phosphate Buffer at Neutral PH. *ChemSusChem* **2020**, *13* (22), 5921–5933.

(351) Katsounaros, I.; Meier, J. C.; Klemm, S. O.; Topalov, A. A.; Biedermann, P. U.; Auinger, M.; Mayrhofer, K. J. J. The Effective Surface PH during Reactions at the Solid-Liquid Interface. *Electro-chem commun* **2011**, *13* (6), 634–637.

(352) Auinger, M.; Katsounaros, I.; Meier, J. C.; Klemm, S. O.; Biedermann, P. U.; Topalov, A. A.; Rohwerder, M.; Mayrhofer, K. J. J.

Near-Surface Ion Distribution and Buffer Effects during Electrochemical Reactions. *Phys. Chem. Chem. Phys.* **2011**, *13* (36), 16384.

(353) Huang, W.-H.; Lin, C.-Y. Iron Phosphate Modified Calcium Iron Oxide as an Efficient and Robust Catalyst in Electrocatalyzing Oxygen Evolution from Seawater. *Faraday Discuss.* **2019**, *215*, 205–215.

(354) Liu, J.; Liu, X.; Shi, H.; Luo, J.; Wang, L.; Liang, J.; Li, S.; Yang, L.-M.; Wang, T.; Huang, Y.; Li, Q. Breaking the Scaling Relations of Oxygen Evolution Reaction on Amorphous NiFeP Nanostructures with Enhanced Activity for Overall Seawater Splitting. *Appl. Catal., B* **2022**, *302*, 120862.

(355) Ma, T.; Xu, W.; Li, B.; Chen, X.; Zhao, J.; Wan, S.; Jiang, K.; Zhang, S.; Wang, Z.; Tian, Z.; Lu, Z.; Chen, L. The Critical Role of Additive Sulfate for Stable Alkaline Seawater Oxidation on Nickel-Based Electrodes. *Angew. Chem., Int. Ed.* **2021**, *60* (42), 22740–22744.

(356) Zhao, Y.; Jin, B.; Vasileff, A.; Jiao, Y.; Qiao, S.-Z. Interfacial Nickel Nitride/Sulfide as a Bifunctional Electrode for Highly Efficient Overall Water/Seawater Electrolysis. *J. Mater. Chem. A Mater.* **2019**, *7* (14), 8117–8121.

(357) Dionigi, F.; Reier, T.; Pawolek, Z.; Gliech, M.; Strasser, P. Design Criteria, Operating Conditions, and Nickel-Iron Hydroxide Catalyst Materials for Selective Seawater Electrolysis. *ChemSusChem* **2016**, *9* (9), 962–972.

(358) Zhao, Y.; Jin, B.; Zheng, Y.; Jin, H.; Jiao, Y.; Qiao, S. Charge State Manipulation of Cobalt Selenide Catalyst for Overall Seawater Electrolysis. *Adv. Energy Mater.* **2018**, *8* (29), 1801926.

(359) Song, H. J.; Yoon, H.; Ju, B.; Lee, D.-Y.; Kim, D.-W. Electrocatalytic Selective Oxygen Evolution of Carbon-Coated Na2Co 1-x FexP2O7 Nanoparticles for Alkaline Seawater Electrolysis. *ACS Catal.* **2020**, *10* (1), 702–709.

(360) Yu, L.; Wu, L.; McElhenny, B.; Song, S.; Luo, D.; Zhang, F.; Yu, Y.; Chen, S.; Ren, Z. Ultrafast Room-Temperature Synthesis of Porous S-Doped Ni/Fe (Oxy)Hydroxide Electrodes for Oxygen Evolution Catalysis in Seawater Splitting. *Energy Environ. Sci.* **2020**, *13* (10), 3439–3446.

(361) Wu, L.; Yu, L.; Zhang, F.; McElhenny, B.; Luo, D.; Karim, A.; Chen, S.; Ren, Z. Heterogeneous Bimetallic Phosphide Ni2P-Fe2P as an Efficient Bifunctional Catalyst for Water/Seawater Splitting. *Adv. Funct Mater.* **2021**, *31* (1), 2006484.

(362) Wu, L.; Yu, L.; Zhu, Q.; McElhenny, B.; Zhang, F.; Wu, C.; Xing, X.; Bao, J.; Chen, S.; Ren, Z. Boron-Modified Cobalt Iron Layered Double Hydroxides for High Efficiency Seawater Oxidation. *Nano Energy* **2021**, *83*, 105838.

(363) Yu, L.; Zhu, Q.; Song, S.; McElhenny, B.; Wang, D.; Wu, C.; Qin, Z.; Bao, J.; Yu, Y.; Chen, S.; Ren, Z. Non-Noble Metal-Nitride Based Electrocatalysts for High-Performance Alkaline Seawater Electrolysis. *Nat. Commun.* **2019**, *10* (1), 5106.

(364) Kuang, Y.; Kenney, M. J.; Meng, Y.; Hung, W.-H.; Liu, Y.; Huang, J. E.; Prasanna, R.; Li, P.; Li, Y.; Wang, L.; Lin, M.-C.; McGehee, M. D.; Sun, X.; Dai, H. Solar-Driven, Highly Sustained Splitting of Seawater into Hydrogen and Oxygen Fuels. *Proc. Natl. Acad. Sci. U. S. A.* **2019**, *116* (14), 6624–6629.

(365) Zheng, J. Pt-Free NiCo Electrocatalysts for Oxygen Evolution by Seawater Splitting. *Electrochim. Acta* **2017**, *247*, 381–391.

(366) Cheng, F.; Feng, X.; Chen, X.; Lin, W.; Rong, J.; Yang, W. Synergistic Action of Co-Fe Layered Double Hydroxide Electro-catalyst and Multiple Ions of Sea Salt for Efficient Seawater Oxidation at near-Neutral PH. *Electrochim. Acta* **2017**, *251*, 336–343.

(367) Li, P.; Wang, S.; Samo, I. A.; Zhang, X.; Wang, Z.; Wang, C.; Li, Y.; Du, Y.; Zhong, Y.; Cheng, C.; Xu, W.; Liu, X.; Kuang, Y.; Lu, Z.; Sun, X. Common-Ion Effect Triggered Highly Sustained Seawater Electrolysis with Additional NaCl Production. *Research 2020*, **2020**, 2020.

(368) Zeng, K.; Zhang, D. Recent Progress in Alkaline Water Electrolysis for Hydrogen Production and Applications. *Prog. Energy Combust. Sci.* **2010**, *36* (3), 307–326.
(369) WHO. Nutrients in Drinking Water.; Water, Sanitation, and Health Protection and the Human Environment, World Health Organization, 2005.

(370) National Water-Quality Assessment Program. Trace Elements and Radon in Groundwater Across the United States, 1992–2003.

(371) Miller-Ihli, N. J.; Baker, S. A. Trace Element Composition of Municipal Waters in the United States: A Comparison of ICP-AES and ICP-MS Methods. *Journal of Food Composition and Analysis* **2001**, *14* (6), 619–629.

(372) Lange, N. A. *Lange's Handbook of Chemistry*.

(373) Frisch, M. L.; Thanh, T. N.; Arinchtein, A.; Hager, L.; Schmidt, J.; Brückner, S.; Kerres, J.; Strasser, P. Seawater Electrolysis Using All-PGM-Free Catalysts and Cell Components in an Asymmetric Feed. *ACS Energy Lett.* **2023**, *8* (5), 2387–2394.

(374) Zhang, X.; Yang, Y.; Ngo, H. H.; Guo, W.; Wen, H.; Wang, X.; Zhang, J.; Long, T. A Critical Review on Challenges and Trend of Ultrapure Water Production Process. *Science of The Total Environment* **2021**, *785*, 147254.

(375) Karagiannis, I. C.; Soldatos, P. G. Water Desalination Cost Literature: Review and Assessment. *Desalination* **2008**, *223* (1–3), 448–456.

(376) Reddy, K. V.; Ghaffour, N. Overview of the Cost of Desalinated Water and Costing Methodologies. *Desalination* **2007**, *205* (1–3), 340–353.

(377) Jonsson, A.; Massgard, H. An Industrial Perspective on Ultrapure Water Production for Electrolysis. *Examensarbete Inom Teknik*, 2021.

(378) Lee, H.; Jin, Y.; Hong, S. Recent Transitions in Ultrapure Water (UPW) Technology: Rising Role of Reverse Osmosis (RO). *Desalination* **2016**, *399*, 185–197.

(379) Liu, X.; Shanbhag, S.; Bartholomew, T. V.; Whitacre, J. F.; Mauter, M. S. Cost Comparison of Capacitive Deionization and Reverse Osmosis for Brackish Water Desalination. *ACS ES&T Engineering* **2021**, *1* (2), 261–273.

(380) Mohammadi, F.; Sahraei-Ardakani, M.; Al-Abdullah, Y.; Heydt, G. T. *Cost-Benefit Analysis of Desalination: A Power Market Opportunity*. *Electric Power Components and Systems* **2020**, *48* (11), 1091–1101.

(381) The evolution of rates in desalination (Part I). *Smart Water Magazine*.

(382) Ghaffour, N.; Missimer, T. M.; Amy, G. L. Technical Review and Evaluation of the Economics of Water Desalination: Current and Future Challenges for Better Water Supply Sustainability. *Desalination* **2013**, *309*, 197–207.

(383) Jande, Y. A. C.; Minhas, M. B.; Kim, W. S. Ultrapure Water from Seawater Using Integrated Reverse Osmosis-Capacitive Deionization System. *Desalination Water Treat* **2015**, *53* (13), 3482–3490.

(384) Maurya, S.; Shin, S.-H.; Kim, M.-K.; Yun, S.-H.; Moon, S.-H. Stability of Composite Anion Exchange Membranes with Various Functional Groups and Their Performance for Energy Conversion. *J. Membr. Sci.* **2013**, *443*, 28–35.

(385) Hnát, J.; Paidar, M.; Schauer, J.; Bouzek, K. Polymer Anion-Selective Membrane for Electrolytic Water Splitting: The Impact of a Liquid Electrolyte Composition on the Process Parameters and Long-Term Stability. *Int. J. Hydrogen Energy* **2014**, *39* (10), 4779–4787.

(386) Kim, S.; Yang, S. H.; Shin, S.-H.; Cho, H. J.; Jang, J. K.; Kim, T. H.; Oh, S.-G.; Kim, T.-H.; Han, H.; Lee, J. Y. *High-Performance and Durable Anion-Exchange Membrane Water Electrolysers with High-Molecular-Weight Polycarbazole-Based Anion-Conducting Polymer. Energy Environ. Sci.* **2024**, *17* (15), 5399–5409.

(387) Chen, N.; Jiang, Q.; Song, F.; Hu, X. Robust Piperidinium-Enriched Polystyrene Ionomers for Anion Exchange Membrane Fuel Cells and Water Electrolyzers. *ACS Energy Lett.* **2023**, *8* (10), 4043–4051.

(388) Shaik, S.; Kundu, J.; Yuan, Y.; Chung, W.; Han, D.; Lee, U.; Huang, H.; Choi, S. Recent Progress and Perspective in Pure Water-Fed Anion Exchange Membrane Water Electrolyzers. *Adv. Energy Mater.* **2024**, *14* (35), 2470148.

(389) Cho, M. K.; Park, H.-Y.; Lee, H. J.; Kim, H.-J.; Lim, A.; Henkensmeier, D.; Yoo, S. J.; Kim, J. Y.; Lee, S. Y.; Park, H. S.; Jang, J. H. Alkaline Anion Exchange Membrane Water Electrolysis: Effects of Electrolyte Feed Method and Electrode Binder Content. *J. Power Sources* **2018**, *382*, 22–29.

(390) Strmnic, D.; Kodama, K.; van der Vliet, D.; Greeley, J.; Stamenkovic, V. R.; Marković, N. M. The Role of Non-Covalent Interactions in Electrocatalytic Fuel-Cell Reactions on Platinum. *Nat. Chem.* **2009**, *1* (6), 466–472.

(391) Ghoshal, S.; Pivovar, B. S.; Alia, S. M. Evaluating the Effect of Membrane-Ionomer Combinations and Supporting Electrolytes on the Performance of Cobalt Nanoparticle Anodes in Anion Exchange Membrane Electrolyzers. *J. Power Sources* **2021**, *488*, 229433.

(392) Vincent, I.; Kruger, A.; Bessarabov, D. Development of Efficient Membrane Electrode Assembly for Low Cost Hydrogen Production by Anion Exchange Membrane Electrolysis. *Int. J. Hydrogen Energy* **2017**, *42* (16), 10752–10761.

(393) Pavel, C. C.; Cecconi, F.; Emiliani, C.; Santiccioli, S.; Scaffidi, A.; Catanorchi, S.; Comotti, M. Highly Efficient Platinum Group Metal Free Based Membrane-Electrode Assembly for Anion Exchange Membrane Water Electrolysis. *Angew. Chem., Int. Ed.* **2014**, *53* (5), 1378–1381.

(394) Kiessling, A.; Fornaciari, J. C.; Anderson, G.; Peng, X.; Gerstmayr, A.; Gerhardt, M.; McKinney, S.; Serov, A.; Weber, A. Z.; Kim, Y. S.; Zulevi, B.; Danilovic, N. Influence of Supporting Electrolyte on Hydroxide Exchange Membrane Water Electrolysis Performance: Catholyte. *J. Electrochem. Soc.* **2022**, *169* (2), 024510.

(395) Oliveira, A. M.; Setzler, B. P.; Yan, Y. Anode-Fed Anion Exchange Membrane Electrolyzers for Hydrogen Generation Tolerant to Anion Contaminants. *ECS Meeting Abstracts 2022*, MA2022-02 (44), 1679–1679.

(396) Parrondo, J.; Arges, C. G.; Niedzwiecki, M.; Anderson, E. B.; Ayers, K. E.; Ramani, V. Degradation of Anion Exchange Membranes Used for Hydrogen Production by Ultrapure Water Electrolysis. *RSC Adv.* **2014**, *4* (19), 9875.

(397) Krewer, U.; Weinzierl, C.; Ziv, N.; Dekel, D. R. Impact of Carbonation Processes in Anion Exchange Membrane Fuel Cells. *Electrochim. Acta* **2018**, *263*, 433–446.

(398) Hassan, N. U.; Zheng, Y.; Kohl, P. A.; Mustain, W. E. KOH vs Deionized Water Operation in Anion Exchange Membrane Electrolyzers. *J. Electrochem. Soc.* **2022**, *169* (4), 044526.

(399) Osmieri, L.; Yu, H.; Hermann, R. P.; Kreider, M. E.; Meyer, H. M.; Kropf, A. J.; Park, J. H.; Alia, S. M.; Cullen, D. A.; Myers, D. J.; Zelenay, P. Aerogel-Derived Nickel-Iron Oxide Catalysts for Oxygen Evolution Reaction in Alkaline Media. *Applied Catalysis B: Environment and Energy* **2024**, *348*, 123843.

(400) Jang, M. J.; Yang, S. H.; Park, M. G.; Jeong, J.; Cha, M. S.; Shin, S.-H.; Lee, K. H.; Bai, Z.; Chen, Z.; Lee, J. Y.; Choi, S. M. Efficient and Durable Anion Exchange Membrane Water Electrolysis for a Commercially Available Electrolyzer Stack Using Alkaline Electrolyte. *ACS Energy Lett.* **2022**, *7* (8), 2576–2583.

(401) Kwon, C.-Y.; Jeong, J.-Y.; Yang, J.; Park, Y. S.; Jeong, J.; Park, H.; Kim, Y.; Choi, S. M. Effect of Copper Cobalt Oxide Composition on Oxygen Evolution Electrocatalysts for Anion Exchange Membrane Water Electrolysis. *Front Chem.* **2020**, *8*, 600908.

(402) Pandiarajan, T.; John Berchmans, L.; Ravichandran, S. Fabrication of Spinel Ferrite Based Alkaline Anion Exchange Membrane Water Electrolysers for Hydrogen Production. *RSC Adv.* **2015**, *5* (43), 34100–34108.

(403) Faid, A. Y.; Barnett, A. O.; Seland, F.; Sunde, S. Tuning Ni-MoO2 Catalyst-Ionomer and Electrolyte Interaction for Water Electrolyzers with Anion Exchange Membranes. *ACS Appl. Energy Mater.* **2021**, *4* (4), 3327–3340.

(404) Chen, N.; Paek, S. Y.; Lee, J. Y.; Park, J. H.; Lee, S. Y.; Lee, Y. M. High-Performance Anion Exchange Membrane Water Electrolyzers with a Current Density of 7.68 A Cm⁻² and a Durability of 1000 h. *Energy Environ. Sci.* **2021**, *14* (12), 6338–6348.

(405) Feng, Z.; Esteban, P. O.; Gupta, G.; Fulton, D. A.; Mamlouk, M. Highly Conductive Partially Cross-Linked Poly(2,6-Dimethyl-1,4-
Phenylene Oxide) as Anion Exchange Membrane and Ionomer for Water Electrolysis. *Int. J. Hydrogen Energy* **2021**, *46* (75), 37137–37151.

(406) Park, D.; Kim, M.; Lee, H.; Lee, W.; Byeon, J.; Kim, J.; Jang, J.; Park, K. Development of Ni-Ir Oxide Composites as Oxygen Catalysts for an Anion-Exchange Membrane Water Electrolyzer. *Adv. Mater.* *Interfaces* **2022**, *9* (5), 2102063.

(407) Lee, J.; Jung, H.; Park, Y. S.; Woo, S.; Yang, J.; Jang, M. J.; Jeong, J.; Kwon, N.; Lim, B.; Han, J. W.; Choi, S. M. *High-Efficiency Anion-Exchange Membrane Water Electrolyzer Enabled by Ternary Layered Double Hydroxide Anode*. *Small* **2021**, *17* (28), 2100639.

(408) Schweitzer, G. K.; Pesterfield, L. L. *The Aqueous Chemistry of the Elements*; Oxford University Press, 2010.

(409) Dong, X.; Iacocca, R. G.; Bustard, B. L.; Kemp, C. A. J. Investigation of Stainless Steel Corrosion in Ultrahigh-Purity Water and Steam Systems by Surface Analytical Techniques. *J. Mater. Eng. Perform* **2010**, *19* (1), 135–141.

(410) Twight, L.; Tonsberg, A.; Samira, S.; Velinkar, K.; Dumpert, K.; Ou, Y.; Wang, L.; Nikolla, E.; Boettcher, S. W. Trace Fe Activates Perovskite Nickelate OER Catalysts in Alkaline Media via Redox-Active Surface Ni Species Formed during Electrocatalysis. *J. Catal.* **2024**, *432*, 115443.

(411) Stevens, M. B.; Trang, C. D. M.; Enman, L. J.; Deng, J.; Boettcher, S. W. Reactive Fe-Sites in Ni/Fe (Oxy)Hydroxide Are Responsible for Exceptional Oxygen Electrocatalysis Activity. *J. Am. Chem. Soc.* **2017**, *139* (33), 11361–11364.

(412) Lopes, P. P.; Chung, D. Y.; Rui, X.; Zheng, H.; He, H.; Farinazzo Bergamo Dias Martins, P.; Strmcnik, D.; Stamenkovic, V. R.; Zapol, P.; Mitchell, J. F.; Klie, R. F.; Markovic, N. M. Dynamically Stable Active Sites from Surface Evolution of Perovskite Materials during the Oxygen Evolution Reaction. *J. Am. Chem. Soc.* **2021**, *143* (7), 2741–2750.

(413) Ali Akbari, M. S.; Bagheri, R.; Song, Z.; Najafpour, M. M. *Oxygen-Evolution Reaction by Nickel/Nickel Oxide Interface in the Presence of Ferrate(VI)*. *Sci. Rep* **2020**, *10* (1), 8757.

(414) Mlynarek, G.; Paszkiewicz, M.; Radniecka, A. The Effect of Ferric Ions on the Behaviour of a Nickelous Hydroxide Electrode. *J. Appl. Electrochem.* **1984**, *14* (2), 145–149.

(415) Tichenor, R. L. Nickel Oxides-Relation Between Electrochemical and Foreign Ion Content. *Ind. Eng. Chem.* **1952**, *44* (5), 973–977.

(416) Klaus, S.; Cai, Y.; Louie, M. W.; Trotochaud, L.; Bell, A. T. Effects of Fe Electrolyte Impurities on Ni(OH)2/NiOOH Structure and Oxygen Evolution Activity. *J. Phys. Chem. C* **2015**, *119* (13), 7243–7254.

(417) Yu, M.; Budiyanto, E.; Tüysüz, H. Principles of Water Electrolysis and Recent Progress in Cobalt-, Nickel-, and Iron-Based Oxides for the Oxygen Evolution Reaction. *Angew. Chem., Int. Ed.* **2022**, *61* (1), No. e202103824.

(418) Yu, Z.; Bai, Y.; Tsekouras, G.; Cheng, Z. Recent Advances in Ni-Fe (Oxy)Hydroxide Electrocatalysts for the Oxygen Evolution Reaction in Alkaline Electrolyte Targeting Industrial Applications. *Nano Select* **2022**, *3* (4), 766–791.

(419) Song, F.; Busch, M. M.; Lassalle-Kaiser, B.; Hsu, C.-S.; Petkucheva, E.; Bensimon, M.; Chen, H. M.; Corminboeuf, C.; Hu, X. An Unconventional Iron Nickel Catalyst for the Oxygen Evolution Reaction. *ACS Cent Sci.* **2019**, *5* (3), 558–568.

(420) Louie, M. W.; Bell, A. T. An Investigation of Thin-Film Ni-Fe Oxide Catalysts for the Electrochemical Evolution of Oxygen. *J. Am. Chem. Soc.* **2013**, *135* (33), 12329–12337.

(421) Lee, S.; Bai, L.; Hu, X. Deciphering Iron-Dependent Activity in Oxygen Evolution Catalyzed by Nickel-Iron Layered Double Hydroxide. *Angew. Chem.* **2020**, *132* (21), 8149–8154.

(422) Friebel, D.; Louie, M. W.; Bajdich, M.; Sanwald, K. E.; Cai, Y.; Wise, A. M.; Cheng, M.-J.; Sokaras, D.; Weng, T.-C.; Alonso-Mori, R.; Davis, R. C.; Bargar, J. R.; Nørskov, J. K.; Nilsson, A.; Bell, A. T. Identification of Highly Active Fe Sites in (Ni,Fe)OOH for Electrocatalytic Water Splitting. *J. Am. Chem. Soc.* **2015**, *137* (3), 1305–1313.

(423) Enman, L. J.; Burke, M. S.; Batchellor, A. S.; Boettcher, S. W. Effects of Intentionally Incorporated Metal Cations on the Oxygen Evolution Electrocatalytic Activity of Nickel (Oxy)Hydroxide in Alkaline Media. *ACS Catal.* **2016**, *6* (4), 2416–2423.

(424) Corrigan, D. A.; Bendert, R. M. Effect of Coprecipitated Metal Ions on the Electrochemistry of Nickel Hydroxide Thin Films: Cyclic Voltammetry in 1M KOH. *J. Electrochem. Soc.* **1989**, *136* (3), 723–728.

(425) Stevens, M. B.; Enman, L. J.; Korkus, E. H.; Zaffran, J.; Trang, C. D. M.; Asbury, J.; Kast, M. G.; Toroker, M. C.; Boettcher, S. W. Ternary Ni-Co-Fe Oxyhydroxide Oxygen Evolution Catalysts: Intrinsic Activity Trends, Electrical Conductivity, and Electronic Band Structure. *Nano Res.* **2019**, *12* (9), 2288–2295.

(426) Long, X.; Xiao, S.; Wang, Z.; Zheng, X.; Yang, S. Co Intake Mediated Formation of Ultrathin Nanosheets of Transition Metal LDH—an Advanced Electrocatalyst for Oxygen Evolution Reaction. *Chem. Commun.* **2015**, *51* (6), 1120–1123.

(427) Krivina, R. A.; Lindquist, G. A.; Beaudoin, S. R.; Stovall, T. N.; Thompson, W. L.; Twight, L. P.; Marsh, D.; Grzyb, J.; Fabrizio, K.; Hutchison, J. E.; Boettcher, S. W. Anode Catalysts in Anion-Exchange-Membrane Electrolysis without Supporting Electrolyte: Conductivity, Dynamics, and Ionomer Degradation. *Adv. Mater.* **2022**, *34* (35), 2203033.

(428) Shao, Q.; Wang, Y.; Yang, S.; Lu, K.; Zhang, Y.; Tang, C.; Song, J.; Feng, Y.; Xiong, L.; Peng, Y.; Li, Y.; Xin, H. L.; Huang, X. Stabilizing and Activating Metastable Nickel Nanocrystals for Highly Efficient Hydrogen Evolution Electrocatalysis. *ACS Nano* **2018**, *12* (11), 11625–11631.

(429) Hall, D. S.; Bock, C.; MacDougall, B. R. The Electrochemistry of Metallic Nickel: Oxides, Hydroxides, Hydrides and Alkaline Hydrogen Evolution. *J. Electrochem. Soc.* **2013**, *160* (3), F235–F243.

(430) Rommal, H. E. G.; Morgan, P. J. The Role of Absorbed Hydrogen on the Voltage-Time Behavior of Nickel Cathodes in Hydrogen Evolution. *J. Electrochem. Soc.* **1988**, *135* (2), 343–346.

(431) Chen, Z.; Duan, X.; Wei, W.; Wang, S.; Ni, B.-J. Recent Advances in Transition Metal-Based Electrocatalysts for Alkaline Hydrogen Evolution. *J. Mater. Chem. A Mater.* **2019**, *7* (25), 14971–15005.

(432) Raj, I. A.; Vasu, K. I. Transition Metal-Based Cathodes for Hydrogen Evolution in Alkaline Solution: Electrocatalysis on Nickel-Based Ternary Electrolytic Codeposits. *J. Appl. Electrochem.* **1992**, *22* (5), 471–477.

(433) Jin, H.; Wang, X.; Tang, C.; Vasileff, A.; Li, L.; Slattery, A.; Qiao, S. Stable and Highly Efficient Hydrogen Evolution from Seawater Enabled by an Unsaturated Nickel Surface Nitride. *Adv. Mater.* **2021**, *33* (13), 2007508.

(434) Huot, J.-Y. *Hydrogen Evolution and Interface Phenomena on a Nickel Cathode in 30 w/o KOH: I. Kinetics Parameters and Electrode Impedance Between 303 and 363 K.* *J. Electrochem. Soc.* **1989**, *136* (7), 1933–1939.

(435) Divisek, J.; Schmitz, H.; Steffen, B. Electrocatalyst Materials for Hydrogen Evolution. *Electrochim. Acta* **1994**, *39* (11–12), 1723–1731.

(436) Riley, M. A.; Moran, P. J. The Influence of Iron Deposition on the Voltage-Time Behavior of Nickel Cathodes in Alkaline Water Electrolysis. *J. Electrochem. Soc.* **1986**, *133* (4), 760–761.

(437) Mauer, A. E.; Kirk, D. W.; Thorpe, S. J. The Role of Iron in the Prevention of Nickel Electrode Deactivation in Alkaline Electrolysis. *Electrochim. Acta* **2007**, *52* (11), 3505–3509.

(438) Lacconi, G. I.; Villullas, H. M.; Macagno, V. A. The Effect of Metallic Impurities on the Hydrogen Evolution Reaction Rate on Group-Ib Metals in Alkaline Solution. *J. Appl. Electrochem.* **1991**, *21* (11), 1027–1030.

(439) Barati Darband, Gh.; Aliofkhazraei, M.; Rouhagdam, A. S. Facile Electrodeposition of Ternary Ni-Fe-Co Alloy Nanostructure as a Binder Free, Cost-Effective and Durable Electrocatalyst for High-Performance Overall Water Splitting. *J. Colloid Interface Sci.* **2019**, *547*, 407–420.
(440) Gao, F.-Y.; Yu, P.-C.; Gao, M.-R. Seawater Electrolysis Technologies for Green Hydrogen Production: Challenges and Opportunities. *Curr. Opin Chem. Eng.* **2022**, *36*, 100827.

(441) Marin, D.; Perryman, J. T.; Nielander, A.; Jaramillo, T. F.; Hubert, M.; Boettcher, S. W. Evaluating Bipolar Membrane Electrolyzers for Green Hydrogen Production from Impure Water Sources. *ECS Meeting Abstracts 2022*, MA2022-01 (41), 2461-2461.

(442) Vos, J. G.; Liu, Z.; Speck, F. D.; Perini, N.; Fu, W.; Cherevko, S.; Koper, M. T. M. Selectivity Trends Between Oxygen Evolution and Chlorine Evolution on Iridium-Based Double Perovskites in Acidic Media. *ACS Catal.* **2019**, *9* (9), 8561-8574.

(443) Vos, J. G.; Wezendonk, T. A.; Jeremiasse, A. W.; Koper, M. T. M. MnOx/IrOx as Selective Oxygen Evolution Electrocatalyst in Acidic Chloride Solution. *J. Am. Chem. Soc.* **2018**, *140* (32), 10270-10281.

(444) Zhang, F.; Yu, L.; Wu, L.; Luo, D.; Ren, Z. Rational Design of Oxygen Evolution Reaction Catalysts for Seawater Electrolysis. *Trends Chem. Sci.* **2021**, *3* (6), 485-498.

(445) Han, D.; Jiang, Y. M.; Shi, C.; Deng, B.; Li, J. Effect of Temperature, Chloride Ion and PH on the Crevice Corrosion Behavior of SAF 2205 Duplex Stainless Steel in Chloride Solutions. *J. Mater. Sci.* **2012**, *47* (2), 1018-1025.

(446) Jiang, S.; Liu, Y.; Qiu, H.; Su, C.; Shao, Z. High Selectivity Electrocatalysts for Oxygen Evolution Reaction and Anti-Chlorine Corrosion Strategies in Seawater Splitting. *Catalysts 2022*, *12* (3), 261.

(447) Oware Sarfo, K.; Murkute, P.; Isgor, O. B.; Zhang, Y.; Tucker, J.; Árnadóttir, L. Density Functional Theory Study of the Initial Stages of Cl-Induced Degradation of α-Cr₂O₃ Passive Film. *J. Electrochem. Soc.* **2020**, *167* (12), 121508.

(448) *Green Corrosion Chemistry and Engineering: Opportunities and Challenges*; Sharma, S. K., Ed.; Wiley, 2011.

(449) Lyu, X.; Li, J.; Jafta, C. J.; Bai, Y.; Canales, C. P.; Magnus, F.; Ingason, A. S.; Serov, A. Investigation of Oxygen Evolution Reaction with Ni Foam and Stainless-Steel Mesh Electrodes in Alkaline Seawater Electrolysis. *J. Environ. Chem. Eng.* **2022**, *10* (5), 108486.

(450) Haq, T. ul; Haik, Y. Strategies of Anode Design for Seawater Electrolysis: Recent Development and Future Perspective. *Small Science 2022*, *2* (9), 2200030.

(451) Dresp, S.; Ngo Thanh, T.; Klingenhof, M.; Brückner, S.; Hauke, P.; Strasser, P. Efficient Direct Seawater Electrolysers Using Selective Alkaline NiFe-LDH as OER Catalyst in Asymmetric Electrolyte Feeds. *Energy Environ. Sci.* **2020**, *13* (6), 1725-1729.

(452) Yu, M.; Li, J.; Liu, F.; Liu, J.; Xu, W.; Hu, H.; Chen, X.; Wang, W.; Cheng, F. Anionic Formulation of Electrolyte Additive towards Stable Electrocatalytic Oxygen Evolution in Seawater Splitting. *Journal of Energy Chemistry 2022*, *72*, 361-369.

(453) Hausmann, J. N.; Menezes, P. W. Effect of Surface-Adsorbed and Intercalated (Oxy)Anions on the Oxygen Evolution Reaction. *Angew. Chem., Int. Ed.* **2022**, *61* (38), No. e202207279.

(454) Ma, T.; Xu, W.; Li, B.; Chen, X.; Zhao, J.; Wan, S.; Jiang, K.; Zhang, S.; Wang, Z.; Tian, Z.; Lu, Z.; Chen, L. The Critical Role of Additive Sulfate for Stable Alkaline Seawater Oxidation on Nickel-Based Electrodes. *Angew. Chem.* **2021**, *133* (42), 22922-22926.

(455) Yuan, S.; Zhao, C.; Cai, X.; An, L.; Shen, S.; Yan, X.; Zhang, J. Bubble Evolution and Transport in PEM Water Electrolysis: Mechanism, Impact, and Management. *Prog. Energy Combust. Sci.* **2023**, *96*, 101075.

(456) Henkensmeier, D.; Najibah, M.; Harms, C.; Žitka, J.; Hnát, J.; Bouzek, K. Overview: State-of-the Art Commercial Membranes for Anion Exchange Membrane Water Electrolysis. *Journal of Electrochemical Energy Conversion and Storage 2021*, *18* (2), 024001.

(457) Rojas, N.; Sánchez-Molina, M.; Sevilla, G.; Amores, E.; Almandoz, E.; Esparza, J.; Cruz Vivas, M. R.; Colominas, C. Coated Stainless Steels Evaluation for Bipolar Plates in PEM Water Electrolysis Conditions. *Int. J. Hydrogen Energy* **2021**, *46* (51), 25929-25943.

(458) Xiao, L.; Zhang, S.; Pan, J.; Yang, C.; He, M.; Zhuang, L.; Lu, J. First Implementation of Alkaline Polymer Electrolyte Water

Electrolysis Working Only with Pure Water. *Energy Environ. Sci.* **2012**, *5* (7), 7869.

(459) Leng, Y.; Chen, G.; Mendoza, A. J.; Tighe, T. B.; Hickner, M. A.; Wang, C.-Y. Solid-State Water Electrolysis with an Alkaline Membrane. *J. Am. Chem. Soc.* **2012**, *134* (22), 9054-9057.

(460) Park, J. E.; Park, S.; Kim, M.-J.; Shin, H.; Kang, S. Y.; Cho, Y.-H.; Sung, Y.-E. Three-Dimensional Unified Electrode Design Using a NiFeOOH Catalyst for Superior Performance and Durable Anion-Exchange Membrane Water Electrolyzers. *ACS Catal.* **2022**, *12* (1), 135-145.

(461) Hua, D.; Huang, J.; Fabbri, E.; Rafique, M.; Song, B. Development of Anion Exchange Membrane Water Electrolysis and the Associated Challenges: A Review. *ChemElectroChem.* **2023**, *10* (1), No. e202200999.

(462) Lindquist, G. A.; Gaitor, J. C.; Thompson, W. L.; Brogden, V.; Noonan, K. J. T.; Boettcher, S. W. Oxidative Instability of Ionomers in Hydroxide-Exchange-Membrane Water Electrolyzers. *Energy Environ. Sci.* **2023**, *16* (10), 4373-4387.

(463) Zhang, L.; Xu, Q.; Hu, Y.; Chen, L.; Jiang, H. Benchmarking the PH-Stability Relationship of Metal Oxide Anodes in Anion Exchange Membrane Water Electrolysis. *ACS Sustain Chem. Eng.* **2023**, *11* (36), 13251-13259.

(464) Choe, Y.-K.; Fujimoto, C.; Lee, K.-S.; Dalton, L. T.; Ayers, K.; Henson, N. J.; Kim, Y. S. Alkaline Stability of Benzyl Trimethyl Ammonium Functionalized Polyaromatics: A Computational and Experimental Study. *Chem. Mater.* **2014**, *26* (19), 5675-5682.

(465) Li, D.; Matanovic, I.; Lee, A. S.; Park, E. J.; Fujimoto, C.; Chung, H. T.; Kim, Y. S. Phenyl Oxidation Impacts the Durability of Alkaline Membrane Water Electrolyzer. *ACS Appl. Mater. Interfaces* **2019**, *11* (10), 9696-9701.

(466) Chen, N.; Lu, C.; Li, Y.; Long, C.; Zhu, H. Robust Poly(Aryl Piperidinium)/N-Spirocyclic Poly(2,6-Dimethyl-1,4-Phenyl) for Hydroxide-Exchange Membranes. *J. Membr. Sci.* **2019**, *572*, 246-254.

(467) Zeng, L.; Zhao, T. S.; Zhang, R. H.; Xu, J. B. NiCo₂O₄ Nanowires@MnOx Nanoflakes Supported on Stainless Steel Mesh with Superior Electrocatalytic Performance for Anion Exchange Membrane Water Splitting. *Electrochem commun* **2018**, *87*, 66-70.

(468) Wu, X.; Scott, K.; Xie, F.; Alford, N. A Reversible Water Electrolyser with Porous PTFE Based OH- Conductive Membrane as Energy Storage Cells. *J. Power Sources* **2014**, *246*, 225-231.

(469) Park, Y. S.; Jeong, J.; Noh, Y.; Jang, M. J.; Lee, J.; Lee, K. H.; Lim, D. C.; Seo, M. H.; Kim, W. B.; Yang, J.; Choi, S. M. Commercial Anion Exchange Membrane Water Electrolyzer Stack through Non-Precious Metal Electrocatalysts. *Appl. Catal., B* **2021**, *292*, 120170.

(470) Motealleh, B.; Liu, Z.; Masel, R. I.; Sculley, J. P.; Richard Ni, Z.; Meroueh, L. Next-Generation Anion Exchange Membrane Water Electrolyzers Operating for Commercially Relevant Lifetimes. *Int. J. Hydrogen Energy* **2021**, *46* (5), 3379-3386.

(471) Huang, G.; Mandal, M.; Hassan, N. U.; Groenhout, K.; Dobbs, A.; Mustain, W. E.; Kohl, P. A. Ionomer Optimization for Water Uptake and Swelling in Anion Exchange Membrane Electrolyzer: Oxygen Evolution Electrode. *J. Electrochem. Soc.* **2020**, *167* (16), 164514.

(472) Cha, M. S.; Park, J. E.; Kim, S.; Han, S.-H.; Shin, S.-H.; Yang, S. H.; Kim, T.-H.; Yu, D. M.; So, S.; Hong, Y. T.; Yoon, S. J.; Oh, S.-G.; Kang, S. Y.; Kim, O.-H.; Park, H. S.; Bae, B.; Sung, Y.-E.; Cho, Y.-H.; Lee, J. Y. Poly(Carbazole)-Based Anion-Conducting Materials with High Performance and Durability for Energy Conversion Devices. *Energy Environ. Sci.* **2020**, *13* (10), 3633-3645.

(473) Maurya, S.; Noh, S.; Matanovic, I.; Park, E. J.; Narvaez Villarrubia, C.; Martinez, U.; Han, J.; Bae, C.; Kim, Y. S. Rational Design of Polyaromatic Ionomers for Alkaline Membrane Fuel Cells with > 1 W Cm⁻² Power Density. *Energy Environ. Sci.* **2018**, *11* (11), 3283-3291.

(474) Park, A. M.; Owczarczyk, Z. R.; Garner, L. E.; Yang-Neyerlin, A. C.; Long, H.; Antunes, C. M.; Sturgeon, M. R.; Lindell, M. J.; Hamrock, S. J.; Yandrasits, M.; Pivovar, B. S. Synthesis and Characterization of Perfluorinated Anion Exchange Membranes. *ECS Trans* **2017**, *80* (8), 957-966.
(475) Park, E. J.; Maurya, S.; Hibbs, M. R.; Fujimoto, C. H.; Kreuer, K.-D.; Kim, Y. S. Alkaline Stability of Quaternized Diels-Alder Polyphenylenes. *Macromolecules* **2019**, *52* (14), 5419–5428.

(476) Arges, C. G.; Ramani, V. Two-Dimensional NMR Spectroscopy Reveals Cation-Triggered Backbone Degradation in Polysulfone-Based Anion Exchange Membranes. *Proc. Natl. Acad. Sci. U. S. A.* **2013**, *110* (7), 2490–2495.

(477) Mustain, W. E.; Chatenet, M.; Page, M.; Kim, Y. S. Durability Challenges of Anion Exchange Membrane Fuel Cells. *Energy Environ. Sci.* **2020**, *13* (9), 2805–2838.

(478) Parrondo, J.; Wang, Z.; Jung, M.-S. J.; Ramani, V. Reactive Oxygen Species Accelerate Degradation of Anion Exchange Membranes Based on Polyphenylene Oxide in Alkaline Environments. *Phys. Chem. Chem. Phys.* **2016**, *18* (29), 19705–19712.

(479) Zhang, Y.; Parrondo, J.; Sankarasubramanian, S.; Ramani, V. Detection of Reactive Oxygen Species in Anion Exchange Membrane Fuel Cells Using In Situ Fluorescence Spectroscopy. *ChemSusChem* **2017**, *10* (15), 3056–3062.

(480) Zhegur, A.; Gjineci, N.; Willdorf-Cohen, S.; Mondal, A. N.; Diesendruck, C. E.; Gavish, N.; Dekel, D. R. Changes of Anion Exchange Membrane Properties During Chemical Degradation. *ACS Appl. Polym. Mater.* **2020**, *2* (2), 360–367.

(481) Indusekhar, V. K.; Krishnaswamy, N. Water Transport Studies on Interpolymer Ion-Exchange Membranes. *Desalination* **1985**, *52* (3), 309–316.

(482) Peng, J.; Roy, A. L.; Greenbaum, S. G.; Zawodzinski, T. A. Effect of CO2 Absorption on Ion and Water Mobility in an Anion Exchange Membrane. *J. Power Sources* **2018**, *380*, 64–75.

(483) Wierzbicki, S.; Douglin, J. C.; Kostuch, A.; Dekel, D. R.; Kruczala, K. Are Radicals Formed During Anion-Exchange Membrane Fuel Cell Operation? *J. Phys. Chem. Lett.* **2020**, *11* (18), 7630–7636.

(484) Diesendruck, C. E.; Dekel, D. R. Water - A Key Parameter in the Stability of Anion Exchange Membrane Fuel Cells. *Curr. Opin Electrochem. 2018*, *9*, 173–178.

(485) Alexander, C. T.; Abakumov, A. M.; Forslund, R. P.; Johnston, K. P.; Stevenson, K. J. Role of the Carbon Support on the Oxygen Reduction and Evolution Activities in LaNiO₃ Composite Electrodes in Alkaline Solution. *ACS Appl. Energy Mater.* **2018**, *1* (4), 1549–1558.

(486) Sugawara, T.; Kawashima, N.; Murakami, T. N. Kinetic Study of Nafion Degradation by Fenton Reaction. *J. Power Sources* **2011**, *196* (5), 2615–2620.

(487) Yazili, D.; Marini, E.; Saatkamp, T.; Münchinger, A.; de Wild, T.; Gubler, L.; Titvinidze, G.; Schuster, M.; Schare, C.; Jörissen, L.; Kreuer, K.-D. Sulfonated Poly(Phenylene Sulfone) Blend Membranes Finding Their Way into Proton Exchange Membrane Fuel Cells. *J. Power Sources* **2023**, *563*, 232791.

(488) de Wild, T.; Nemeth, T.; Nolte, T. M.; Schmidt, T. J.; Nauser, T.; Gubler, L. Possible Repair Mechanism for Hydrocarbon-Based Ionomers Following Damage by Radical Attack. *J. Electrochem. Soc.* **2021**, *168* (5), 054514.

(489) Kern, W. The Evolution of Silicon Wafer Cleaning Technology. *J. Electrochem. Soc.* **1990**, *137* (6), 1887–1892.

(490) Lindquist, G. A.; Gaitor, J. C.; Thompson, W. L.; Brogden, V.; Noonan, K. J. T.; Boettcher, S. W. Oxidative Instability of Ionomers in Hydroxide-Exchange-Membrane Water Electrolyzers. *Energy Environ. Sci.* **2023**, *16* (10), 4373–4387.

(491) Martens, I.; Melo, L. G. A.; West, M. M.; Wilkinson, D. P.; Bizzotto, D.; Hitchcock, A. P. Imaging Reactivity of the Pt-Ionomer Interface in Fuel-Cell Catalyst Layers. *ACS Catal.* **2020**, *10* (15), 8285–8292.

(492) Tao, H. B.; Xu, Y.; Huang, X.; Chen, J.; Pei, L.; Zhang, J.; Chen, J. G.; Liu, B. A General Method to Probe Oxygen Evolution Intermediates at Operating Conditions. *Joule* **2019**, *3* (6), 1498–1509.

(493) Hübner, G.; Roduner, E. EPR Investigation of HO/ Radical Initiated Degradation Reactions of Sulfonated Aromatics as Model Compounds for Fuel Cell Proton Conducting Membranes. *J. Mater. Chem.* **1999**, *9* (2), 409–418.

(494) Gottesfeld, S.; Dekel, D. R.; Page, M.; Bae, C.; Yan, Y.; Zelenay, P.; Kim, Y. S. Anion Exchange Membrane Fuel Cells: Current Status and Remaining Challenges. *J. Power Sources* **2018**, *375*, 170–184.

(495) Chen, B.; Mardle, P.; Holdcroft, S. Probing the Effect of Ionomer Swelling on the Stability of Anion Exchange Membrane Water Electrolyzers. *J. Power Sources* **2022**, *550*, 232134.

(496) Hugar, K. M.; Kostalik, H. A.; Coates, G. W. Imidazolium Cations with Exceptional Alkaline Stability: A Systematic Study of Structure-Stability Relationships. *J. Am. Chem. Soc.* **2015**, *137* (27), 8730–8737.

(497) Maurya, S.; Dumont, J. H.; Villarrubia, C. N.; Matanovic, I.; Li, D.; Kim, Y. S.; Noh, S.; Han, J.; Bae, C.; Miller, H. A.; Fujimoto, C. H.; Dekel, D. R. Surface Adsorption Affects the Performance of Alkaline Anion-Exchange Membrane Fuel Cells. *ACS Catal.* **2018**, *8* (10), 9429–9439.

(498) Matanovic, I.; Maurya, S.; Park, E. J.; Jeon, J. Y.; Bae, C.; Kim, Y. S. Adsorption of Polyaromatic Backbone Impacts the Performance of Anion Exchange Membrane Fuel Cells. *Chem. Mater.* **2019**, *31* (11), 4195–4204.

(499) Maurya, S.; Fujimoto, C. H.; Hibbs, M. R.; Narvaez Villarrubia, C.; Kim, Y. S. Toward Improved Alkaline Membrane Fuel Cell Performance Using Quaternized Aryl-Ether Free Polyaromatics. *Chem. Mater.* **2018**, *30* (7), 2188–2192.

(500) Chung, H. T.; Martinez, U.; Matanovic, I.; Kim, Y. S. Cation-Hydroxide-Water Cadsorption Inhibits the Alkaline Hydrogen Oxidation Reaction. *J. Phys. Chem. Lett.* **2016**, *7* (22), 4464–4469.

(501) Wang, L.; Saveleva, V. A.; Eslamibidgoli, M. J.; Antipin, D.; Bouillet, C.; Biswas, I.; Gago, A. S.; Hosseiny, S. S.; Gazdzicki, P.; Eikerling, M. H.; Savinova, E. R.; Friedrich, K. A. Deciphering the Exceptional Performance of NiFe Hydroxide for the Oxygen Evolution Reaction in an Anion Exchange Membrane Electrolyzer. *ACS Appl. Energy Mater.* **2022**, *5* (2), 2221–2230.

(502) Meena, A.; Thangavel, P.; Jeong, D. S.; Singh, A. N.; Jana, A.; Im, H.; Nguyen, D. A.; Kim, K. S. Crystalline-Amorphous Interface of Mesoporous Ni2P @ FePOxHy for Oxygen Evolution at High Current Density in Alkaline-Anion-Exchange-Membrane Water-Electrolyzer. *Appl. Catal., B* **2022**, *306*, 121127.

(503) Yang, J.; Jang, M. J.; Zeng, X.; Park, Y. S.; Lee, J.; Choi, S. M.; Yin, Y. Non-Precious Electrocatalysts for Oxygen Evolution Reaction in Anion Exchange Membrane Water Electrolysis: A Mini Review. *Electrochem commun* **2021**, *131*, 107118.

(504) Thangavel, P.; Ha, M.; Kumaraguru, S.; Meena, A.; Singh, A. N.; Harzandi, A. M.; Kim, K. S. Graphene-Nanoplatelets-Supported NiFe-MOF: High-Efficiency and Ultra-Stable Oxygen Electrodes for Sustained Alkaline Anion Exchange Membrane Water Electrolysis. *Energy Environ. Sci.* **2020**, *13* (10), 3447–3458.

(505) Thangavel, P.; Kim, G.; Kim, K. S. Electrochemical Integration of Amorphous NiFe (Oxy)Hydroxides on Surface-Activated Carbon Fibers for High-Efficiency Oxygen Evolution in Alkaline Anion Exchange Membrane Water Electrolysis. *J. Mater. Chem. A Mater.* **2021**, *9* (24), 14043–14051.

(506) Wiegmann, T.; Pacheco, I.; Reikowski, F.; Stettner, J.; Qiu, C.; Bouvier, M.; Bertram, M.; Faisal, F.; Brummel, O.; Libuda, J.; Drnec, J.; Allongue, P.; Maroun, F.; Magnussen, O. M. Operando Identification of the Reversible Skin Layer on Co₃O₄ as a Three-Dimensional Reaction Zone for Oxygen Evolution. *ACS Catal.* **2022**, *12* (6), 3256–3268.

(507) Li, H.; Chen, Y.; Seow, J. Z. Y.; Liu, C.; Fisher, A. C.; Ager, J. W.; Xu, Z. J. Surface Reconstruction of Perovskites for Water Oxidation: The Role of Initial Oxides' Bulk Chemistry. *Small Science* **2022**, *2* (1), 2100048.

(508) Boucly, A.; Artiglia, L.; Fabbri, E.; Palagin, D.; Aegerter, D.; Pergolesi, D.; Novotny, Z.; Comini, N.; Diulus, J. T.; Huthwelker, T.; Ammann, M.; Schmidt, T. J. Direct Evidence of Cobalt Oxyhydroxide Formation on a La<sub>0.2</sub>Sr<sub>0.8</sub>CoO<sub>3</sub> Perovskite Water Splitting Catalyst. *J. Mater. Chem. A Mater.* **2022**, *10* (5), 2434–2444.

(509) Risch, M.; Grimaud, A.; May, K. J.; Stoerzinger, K. A.; Chen, T. J.; Mansour, A. N.; Shao-Horn, Y. Structural Changes of Cobalt-
Based Perovskites upon Water Oxidation Investigated by EXAFS. J. Phys. Chem. C **2013**, *117* (17), 8628–8635.

(510) May, K. J.; Carlton, C. E.; Stoerzinger, K. A.; Risch, M.; Suntivich, J.; Lee, Y.-L.; Grimaud, A.; Shao-Horn, Y. Influence of Oxygen Evolution during Water Oxidation on the Surface of Perovskite Oxide Catalysts. J. Phys. Chem. Lett. **2012**, *3* (22), 3264–3270.

(511) Liu, J.; Jia, E.; Stoerzinger, K. A.; Wang, L.; Wang, Y.; Yang, Z.; Shen, D.; Engelhard, M. H.; Bowden, M. E.; Zhu, Z.; Chambers, S. A.; Du, Y. Dynamic Lattice Oxygen Participation on Perovskite LaNiO₃ during Oxygen Evolution Reaction. J. Phys. Chem. C **2020**, *124* (28), 15386–15390.

(512) Adiga, P.; Wang, L.; Wong, C.; Matthews, B. E.; Bowden, M. E.; Spurgeon, S. R.; Sterbinsky, G. E.; Blum, M.; Choi, M.-J.; Tao, J.; Kaspar, T. C.; Chambers, S. A.; Stoerzinger, K. A.; Du, Y. Correlation between Oxygen Evolution Reaction Activity and Surface Compositional Evolution in Epitaxial La<sub>0.5</sub> Sr<sub>0.5</sub> Ni<sub>1-x</sub> Fe<sub>x</sub> O<sub>3-δ</sub> Thin Films. Nanoscale **2023**, *15* (3), 1119–1127.

(513) Gong, M.; Wang, D.-Y.; Chen, C.-C.; Hwang, B.-J.; Dai, H. A Mini Review on Nickel-Based Electrocatalysts for Alkaline Hydrogen Evolution Reaction. Nano Res. **2016**, *9* (1), 28–46.

(514) Lei, C.; Yang, K.; Wang, G.; Wang, G.; Lu, J.; Xiao, L.; Zhuang, L. Impact of Catalyst Reconstruction on the Durability of Anion Exchange Membrane Water Electrolysis. ACS Sustain Chem. Eng. **2022**, *10* (50), 16725–16733.

(515) Vincent, I.; Lee, E.-C.; Kim, H.-M. Comprehensive Impedance Investigation of Low-Cost Anion Exchange Membrane Electrolysis for Large-Scale Hydrogen Production. Sci. Rep **2021**, *11* (1), 293.

(516) Razmjooei, F.; Morawietz, T.; Taghizadeh, E.; Hadjixenophontos, E.; Mues, L.; Gerle, M.; Wood, B. D.; Harms, C.; Gago, A. S.; Ansar, S. A.; Friedrich, K. A. Increasing the Performance of an Anion-Exchange Membrane Electrolyzer Operating in Pure Water with a Nickel-Based Microporous Layer. Joule **2021**, *5* (7), 1776–1799.

(517) Wang, L.; Adiga, P.; Zhao, J.; Samarakoon, W. S.; Stoerzinger, K. A.; Spurgeon, S. R.; Matthews, B. E.; Bowden, M. E.; Sushko, P. V.; Kaspar, T. C.; Sterbinsky, G. E.; Heald, S. M.; Wang, H.; Wangoh, L. W.; Wu, J.; Guo, E.-J.; Qian, H.; Wang, J.; Varga, T.; Thevuthasan, S.; Feng, Z.; Yang, W.; Du, Y.; Chambers, S. A. Understanding the Electronic Structure Evolution of Epitaxial LaNi<sub>1-x</sub> Fe<sub>x</sub> O<sub>3</sub> Thin Films for Water Oxidation. Nano Lett. **2021**, *21* (19), 8324–8331.

(518) Anantharaj, S.; Kundu, S.; Noda, S. "The Fe Effect": A Review Unveiling the Critical Roles of Fe in Enhancing OER Activity of Ni and Co Based Catalysts. Nano Energy **2021**, *80*, 105514.

(519) Zhang, T.; Nellist, M. R.; Enman, L. J.; Xiang, J.; Boettcher, S. W. Modes of Fe Incorporation in Co-Fe (Oxy)Hydroxide Oxygen Evolution Electrocatalysts. ChemSusChem **2019**, *12* (9), 2015–2021.

(520) Farhat, R.; Dhainy, J.; Halaoui, L. I. OER Catalysis at Activated and Codeposited NiFe-Oxo/Hydroxide Thin Films Is Due to Postdeposition Surface-Fe and Is Not Sustainable without Fe in Solution. ACS Catal. **2020**, *10* (1), 20–35.

(521) Volk, E. K.; Kwon, S.; Alia, S. M. Catalytic Activity and Stability of Non-Platinum Group Metal Oxides for the Oxygen Evolution Reaction in Anion Exchange Membrane Electrolyzers. J. Electrochem. Soc. **2023**, *170* (6), 064506.

(522) Jayashree, R. S.; Vishnu Kamath, P. Suppression of the α → β-Nickel Hydroxide Transformation in Concentrated Alkali: Role of Dissolved Cations. J. Appl. Electrochem. **2001**, *31* (12), 1315–1320.

(523) Poynton, S. D.; Slade, R. C. T.; Omasta, T. J.; Mustain, W. E.; Escudero-Cid, R.; Ocón, P.; Varcoe, J. R. Preparation of Radiation-Grafted Powders for Use as Anion Exchange Ionomers in Alkaline Polymer Electrolyte Fuel Cells. J. Mater. Chem. A **2014**, *2* (14), 5124–5130.

(524) Omasta, T. J.; Wang, L.; Peng, X.; Lewis, C. A.; Varcoe, J. R.; Mustain, W. E. Importance of Balancing Membrane and Electrode Water in Anion Exchange Membrane Fuel Cells. J. Power Sources **2018**, *375*, 205–213.

(525) He, C.; Yang-Neyerlin, A. C.; Pivovar, B. S. Probing Anion Exchange Membrane Fuel Cell Cathodes by Varying Electrocatalysts and Electrode Processing. J. Electrochem. Soc. **2022**, *169* (2), 024507.

(526) Balogun, E.; Cassegrain, S.; Mardle, P.; Adamski, M.; Saatkamp, T.; Holdcroft, S. Nonconformal Particles of Hyper-branched Sulfonated Phenylated Poly(Phenylene) Ionomers as Proton-Conducting Pathways in Proton Exchange Membrane Fuel Cell Catalyst Layers. ACS Energy Lett. **2022**, *7* (6), 2070–2078.

(527) Tran-Phu, T.; Chen, H.; Daiyan, R.; Chatti, M.; Liu, B.; Amal, R.; Liu, Y.; Macfarlane, D. R.; Simonov, A. N.; Tricoli, A. Nanoscale TiO₂ Coatings Improve the Stability of an Earth-Abundant Cobalt Oxide Catalyst during Acidic Water Oxidation. ACS Appl. Mater. Interfaces **2022**, *14* (29), 33130–33140.

(528) Finke, C. E.; Omelchenko, S. T.; Jasper, J. T.; Lichterman, M. F.; Read, C. G.; Lewis, N. S.; Hoffmann, M. R. Enhancing the Activity of Oxygen-Evolution and Chlorine-Evolution Electrocatalysts by Atomic Layer Deposition of TiO₂. Energy Environ. Sci. **2019**, *12* (1), 358–365.

(529) Cherevko, S. Stabilization of Non-Noble Metal Electrocatalysts for Acidic Oxygen Evolution Reaction. Curr. Opin Electrochem **2023**, *38*, 101213.

(530) Marichy, C.; Ercolano, G.; Caputo, G.; Willinger, M. G.; Jones, D.; Rozière, J.; Pinna, N.; Cavaliere, S. ALD SnO₂ Protective Decoration Enhances the Durability of a Pt Based Electrocatalyst. J. Mater. Chem. A Mater. **2016**, *4* (3), 969–975.

(531) Bhardwaj, A. A.; Vos, J. G.; Beatty, M. E. S.; Baxter, A. F.; Koper, M. T. M.; Yip, N. Y.; Esposito, D. V. Ultrathin Silicon Oxide Overlayers Enable Selective Oxygen Evolution from Acidic and Unbuffered PH-Neutral Seawater. ACS Catal. **2021**, *11* (3), 1316–1330.

(532) Beatty, M. E. S.; Gillette, E. I.; Haley, A. T.; Esposito, D. V. Controlling the Relative Fluxes of Protons and Oxygen to Electrocatalytic Buried Interfaces with Tunable Silicon Oxide Overlayers. ACS Appl. Energy Mater. **2020**, *3* (12), 12338–12350.

(533) Speck, F. D.; Ali, F. S. M.; Paul, M. T. Y.; Singh, R. K.; Böhm, T.; Hofer, A.; Kasian, O.; Thiele, S.; Bachmann, J.; Dekel, D. R.; Kallio, T.; Cherevko, S. Improved Hydrogen Oxidation Reaction Activity and Stability of Buried Metal-Oxide Electrocatalyst Interfaces. Chem. Mater. **2020**, *32* (18), 7716–7724.

(534) Obata, K.; Takanabe, K. A Permselective CeO₂ Coating to Improve the Stability of Oxygen Evolution Electrocatalysts. Angew. Chem., Int. Ed. **2018**, *57* (6), 1616–1620.

(535) Chen, L.; Feng, X. Enhanced Catalytic Reaction at an Air-Liquid-Solid Triphase Interface. Chem. Sci. **2020**, *11* (12), 3124–3131.

(536) Jhong, H.-R.; Brushett, F. R.; Kenis, P. J. A. The Effects of Catalyst Layer Deposition Methodology on Electrode Performance. Adv. Energy Mater. **2013**, *3* (5), 589–599.

(537) Berlinger, S. A.; McCloskey, B. D.; Weber, A. Z. Probing Ionomer Interactions with Electrocatalyst Particles in Solution. ACS Energy Lett. **2021**, *6* (6), 2275–2282.

(538) Peron, J.; Mani, A.; Zhao, X.; Edwards, D.; Adachi, M.; Soboleva, T.; Shi, Z.; Xie, Z.; Navessin, T.; Holdcroft, S. Properties of Nafion® NR-211 Membranes for PEMFCs. J. Membr. Sci. **2010**, *356* (1–2), 44–51.

(539) Evans, C. E.; Noble, R. D.; Nazeri-Thompson, S.; Nazeri, B.; Koval, C. A. Role of Conditioning on Water Uptake and Hydraulic Permeability of Nafion® Membranes. J. Membr. Sci. **2006**, *279* (1–2), 521–528.

(540) Bezmalinović, D.; Radošević, J.; Barbir, F. Initial Conditioning of Polymer Eelectrolyte Membrane Fuel Cell by Temperature and Potential Cycling. Acta Chim Slov **2015**, *62* (1), 83–87.

(541) Qi, Z.; Kaufman, A. Quick and Effective Activation of Proton-Exchange Membrane Fuel Cells. J. Power Sources **2003**, *114* (1), 21–31.

(542) Balogun, E.; Barnett, A. O.; Holdcroft, S. Cathode Starvation as an Accelerated Conditioning Procedure for Perfluorosulfonic Acid Ionomer Fuel Cells. Journal of Power Sources Advances **2020**, *3*, 100012.
(543) Divekar, A. G.; Yang-Neyerlin, A. C.; Antunes, C. M.; Strasser, D. J.; Motz, A. R.; Seifert, S. S.; Zuo, X.; Pivovar, B. S.; Herring, A. M. In-Depth Understanding of the CO₂ Limitation of Air Fed Anion Exchange Membrane Fuel Cells. *Sustain Energy Fuels* 2020, 4 (4), 1801–1811.

(544) Tsotridis, G.; Pilenga, A. EU Harmonized Protocols for Testing of Low Temperature Water Electrolysis; 2021, DOI: 10.2760/58880.

(545) Aßmann, P.; Gago, A. S.; Gazdzicki, P.; Friedrich, K. A.; Wark, M. Toward Developing Accelerated Stress Tests for Proton Exchange Membrane Electrolyzers. *Curr. Opin Electrochem* 2020, 21, 225–233.

(546) International Renewable Energy Agency. Hydrogen: A Renewable Energy Perspective.

(547) Narayanaru, S.; Miyanishi, S.; Kuroki, H.; Anilkumar, G. M.; Yamaguchi, T. Start-Stop Cyclic Durability Analysis of Membrane-Electrode Assemblies Using Polyflourene-Based Electrolytes for an Anion-Exchange Membrane Water Electrolyzer. *ACS Sustain Chem. Eng.* 2023, 11 (25), 9295–9302.

(548) Oda, K.; Kuroda, Y.; Mitsushima, S. Investigation of Charge-Discharging Behavior of Metal Oxide-Based Anode Electrocatalysts for Alkaline Water Electrolysis to Suppress Degradation Due to Reverse Current. *Electrocatalysis* 2023, 14 (3), 499–510.