bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Modular in-Situ Cell to Monitor Gas Diffusion Electrodes during ORR and CO2RR
Authors: Hoffmann Hendrik , Paulisch Melanie Cornelia , Osiewacz Jens , Manke Ingo , Turek Thomas , Roth Christina 
Published: July 2022

Metal-based gas diffusion electrodes (GDE) are utilized to achieve high current densities during the reaction in energy conversion systems, such as chlor-alkali electrolysis or the electrochemical reduction of carbon dioxide. By intense contact between the liquid and the gas phase with the catalytically active surfaces within the metallic electrodes, industrially required current densities can be accomplished. Their almost bulk-like silver structures with the 3D porous design and the strong absorption of the extended material make radiographic measurements extremely demanding. To receive in-depth information on electrolyte intrusion into the electrode's porous structure and the distribution during electrochemical measurements, lab-based and synchrotron radiography allows for monitoring this process operando 1, 2
.
In this work, we describe the development of a cell design that can be modularly adapted and successfully used to monitor both the ORR and the CO2RR as exemplary and currently very relevant examples of gas-liquid reactions. The applied half-cell set-up designed for ORR allowed for operando synchrotron radiation measurements at electrochemically stable operation at viable industrial conditions and current densities to follow the electrolyte distribution within Ag-based GDE during chlor-alkali-electrolysis. By adding one additional electrolyte compartment, extending the X-ray window, and implementing an anion exchange membrane, the in-house built half-cell set-up designed for operando synchrotron radiation measurements of ORR, was converted into a full-cell set-up for imaging CO2RR of strongly absorbing metal-based GDEs. With the reported cell design, we were able to observe the electrolyte distribution within GDEs during cell operation at technically relevant current densities for CO2RR up to 300 mAcm-2 (Figure 1). By high-resolution synchrotron radiation operando measurements, we demonstrated crystallization of electrolyte caused by the hydrophobic character of the GDE. At high overpotentials, hydrogen evolution reaction caused blockade of the Ag-based GDE, resulting in declining current densities, which could be imaged and monitored during realistic potentiostatic operation.

M. C. Paulisch, M. Gebhard, D. Franzen, A. Hilger, M. Osenberg, S. Marathe, C. Rau, B. Ellendorff, T. Turek, C. Roth and I. Manke, ACS Appl. Energy Mater.,
4(8), 7497–7503 (2021).

M. Gebhard, M. Paulisch, A. Hilger, D. Franzen, B. Ellendorff, T. Turek, I. Manke and C. Roth, Materials (Basel, Switzerland),
12(8) (2019).

Figure 1
Achieving High CO2 Electrocatalytic Activity By Tailoring Cation-Size Mismatch in Double Perovskite Oxides
Authors: Bae Kyung Taek , Lee Kang Taek 
Published: July 2022

Conversion of CO2 into useful chemical products by solid oxide electrolysis cells (SOECs) is a promising technology capable of reducing CO2 concentration for a carbon-neutral society [1]. This electrochemical device has several advantages such as high-energy efficiency and fast electrode kinetics due to its high operating temperature. Conventionally, Ni/YSZ cermet has been widely used as the cathode material of CO2 electrolysis system. However, they are prone to degrade under CO2 atmosphere due to the oxidation of nickel, particle agglomeration, and carbon deposition. Therefore, the development of alternative cathode materials with high electrocatalytic activity and good long-term stability for CO2 reduction reaction (CO2RR) is highly needed.
The perovskite-type mixed ionic and electronic conducting (MIEC) oxides are widely investigated as the promising alternatives to the Ni/YSZ cermet cathode. Among them, double perovskite oxides PrBaCo2O5+d(PBCO) material is attracting attention because of high oxygen surface exchange, diffusion coefficients and adequate mixed ionic and electronic conductivity. However, this material is easily degraded in the presence of CO2 impurity, with the formation of BaCO3 nanoparticles [2]. To overcome this issue, doping the B-site Co cations with transition metals and tailoring the cation mismatch by controlling A-site dopant ratio in PBCO were selected as a novel strategy. As a result, it was proved that co-doping was an effective way to improve both electrochemical and surface chemical stability. Our design strategy could benefit the preparation of highly active and stable cathodes for direct CO2 reduction for SOECs.

References

[1] Lee, Seokhee, et al. Advanced Energy Materials (2021): 2100339.
[2] Zhu, Lin, et al. Applied Surface Science 416 (2017): 649-655.
Understanding the Temperature Effects on CO2 Electrolysis Performance at High Current Densities
Authors: Giron Rodriguez Carlos Andres , Moss Asger Barkholt , Garg Sahil , Chorkendorff Ib , Seger Brian 
Published: July 2022

The CO2 electrolysis driven with renewable sources is a promising alternative to mitigate greenhouse gas emissions by converting CO2 into valuable feedstocks and storing renewable electrical energy 1. Membrane electrode assemblies (MEAs) equipped with gas diffusion electrodes (GDEs) have shown great potential to overcome the current limitation of aqueous-fed systems while bringing this technology to economically-competing levels 2. In the last decade, many studies have been devoted to developing efficient catalyst materials and reactor designs; however, the effect of operating conditions such as temperature has not been thoroughly studied3. Given that the temperature affects CO2 electrolysis in a complex way (simultaneous effects on the CO2 diffusivity, solubility, the ionic conductivity of the membrane, and surface wettability of the GDE4), a systematic investigation is necessary to determine temperature influence on the product distribution
In this study, we investigate the temperature effects on CO2 electrolysis of Cu-based GDEs in an MEA-based approach in a temperature range between 25 and 80˚C, to enhance the selectivity of C2+ products and the energy efficiency while suppressing the hydrogen evolution (HER) and the degradation of the GDE and the membrane. For this investigation, a robust system for controlling and measuring the temperature of all the system components was developed, and we simultaneously set up proper guidelines to perform these electrocatalytic temperature measurements in a consistent and reproducible way.
For evaluating the temperature influence on electrocatalytic performance, a series of electrochemical measurements such as linear sweep voltammetry (LSV), double-layer capacitance measurements (DLC), potentiostatic and galvanostatic experiments were performed. The obtained results provide insights into how CO2 diffusion, reaction kinetics, and CO2 mass transport vary with temperature and affect the overall performance. We observed improvement in reaction rates and a drop in cell voltages at higher temperatures due to the enhancement of membranes' ionic conductivity and water management. The experiments focused on selectivity and product crossover revealed a specific trend at temperatures above 60˚C for gas and liquid products, setting up the optimal conditions for a stable operation with higher faradaic efficiencies of carbon-based compounds.
1 A. Vasileff, Y. Zheng and S. Z. Qiao, Adv. Energy Mater., 2017, 7, 1–21.
2 T. Burdyny and W. A. Smith, Energy Environ. Sci., 2019, 12, 1442–1453.
3 B. Endrődi, G. Bencsik, F. Darvas, R. Jones, K. Rajeshwar and C. Janáky, Prog. Energy Combust. Sci., 2017, 62, 133–154.
4 A. Löwe, C. Rieg, T. Hierlemann, N. Salas, D. Kopljar, N. Wagner and E. Klemm, ChemElectroChem, 2019, 6, 4497–4506.
(Invited) Renewable Hydrogen Systems Enable Deep Energy Decarbonization of Power and Transportation Sectors
Authors: Haggi Hamed , Fenton James M. , Brooker Paul , Sun Wei 
Published: July 2022

Climate change is one of the most preeminent challenges facing the world. Continued fossil fuel energy consumption at the current trajectory will result in a temperature rise of more than 3.5°C by the year 2050. Melting glaciers, rising sea levels, wildfires, floods, and extreme weather events such as heat waves and large storms, are likely to become more frequent or more intense. The Paris Agreement is a legally binding international treaty to reduce carbon emissions which led to keep the global temperature rise well below 2°C [1]. This target cannot be achieved without deeply decarbonized energy production which focuses on three main factors: 1) Reducing energy consumption through improved efficiency (optimize), 2) Shifting energy demand to electricity and away from combustion of fossil fuels (electrify everything), 3) Shifting entirely to zero-carbon technologies such as solar photovoltaic (PV), wind, hydrogen, etc. to generate electricity (decarbonize). According to the United States (U.S.) Environmental Protection Agency (EPA), the largest contributors to anthropogenic U.S. greenhouse gas emissions in the descending order are transportation (29%), electricity (25%), industry (23%), agriculture (10%), commercial (7%), and residential (6%) [2].
In our previous research, we focused on decarbonization pathways using utility solar, hydrogen consumption and production (electrolyzer, compressor, storage tank, and stationary fuel cells) for improved utilities operation without considering transportation sector demand [3]. Here the focus is on energy decarbonization for both power and hydrogen fueled transportation sector using hydrogen systems. To this end, a vertically integrated 33-node distribution network which is managed by distribution system operator (DSO) is optimized. The DSO manages all the assets in the network including natural gas power plants (combined cycle units and combustion turbine units), solar PV, distributed energy storage systems, hydrogen systems (including storage and refueling station) with the objective of cost minimization. Besides managing the aforementioned technologies, the DSO ensures safe and reliable operation of these assets by considering the technical and physical constraints of the network including voltage regulation, power flow and line congestion management, etc. The DSO in this study also manages the transportation sector hydrogen demand of fuel cell electric vehicles, medium- and heavy-duty vehicles.
Simulation results show that hydrogen demand from the transportation sector is the main driver in sizing of hydrogen system components. Additionally, for the 33-node distribution network to fully supply heavy-duty vehicles demand, natural gas power plants must be operated to supply the required electricity for the electrolyzers to supply hydrogen for these vehicles. Furthermore, different sensitivity analysis for various PV and hydrogen demand penetrations will be presented.
(Invited) Electrified Membranes for Transformation of Nitrate in Wastewaters
Authors: Winter Lea R , Elimelech Menachem 
Published: July 2022

The release of nitrate to the environment from wastewater effluent and agricultural runoff contributes to groundwater contamination, harmful algal blooms, and disruption of biogeochemical nitrogen flows. Typical treatment methods are based on nitrate separation, which produces waste streams that are often discharged to the environment. Alternatively, nitrate conversion via electrochemical reduction eliminates the production of concentrated waste streams while avoiding the addition of reductant or hole scavenger chemicals to accomplish the reaction. However, major challenges for nitrate removal from water via electrochemical conversion involve reducing the use of expensive precious metal electrocatalysts while also improving the reaction activity and selectivity, catalyst stability, and mass transport of nitrate to electrocatalyst active sites. The use of electrochemical membranes as multifunctional porous flow-through electrodes could potentially address these challenges based on improved mass transport and altered kinetics under flow conditions within membrane pores.
Conductive membranes were fabricated using polymers combined with carbonaceous materials such as reduced graphene oxide (rGO) and carbon nanotubes. The rGO was functionalized with non-precious transition metal oxynitride electrocatalysts, where these catalysts showed higher nitrate conversion activity compared to the unsupported transition metal nitrides. The influence of catalyst materials, membrane fabrication process, and filtration conditions on nitrate reduction activity and selectivity were evaluated. In addition to the environmental impacts of closing the nitrogen loop by converting nitrate into innocuous N2, selective nitrate reduction to ammonia provides opportunities for recovery as fertilizer or carbon-free renewable energy storage. The prospects for reactive nitrogen recovery based on nitrate electrochemical conversion to ammonia were analyzed for various potential source waters.
(Digital Presentation) Role of Electronic Structure on Nitrate Reduction to Ammonium: A Periodic Journey
Authors: Carvalho Quinn , Marks Rylee , Stoerzinger Kelsey A 
Published: July 2022

The perturbation of the nitrogen cycle via fertilizer amendment and fossil-fuel combustion has resulted in alarmingly increased nitrate concentrations in groundwater and coastal areas, with global human-health threatening consequences. Denitrification of drinking water, municipal cooling tower waste water, and industrial waste streams is a growing area of energy consumption, though still outpaced by the carbon-intensive Haber-Bosch production of ammonia from nitrogen for fertilizer production. Electrocatalytic nitrate reduction offers a competitive, distributable, and cyclic alternative to conventional fertilizer-production approaches, using electrons as a reducing agent without the need for added chemicals or elevated temperatures and pressures. However, nitrate reduction Faradaic efficiency to desired products (e.g. ammonium) is limited by two primary factors: (1) competition with the process of water reduction (i.e. reducing protons to form hydrogen gas); and (2) a complex reduction pathway where nitric oxide (NO) plays a critical role in determining selectivity.
Here we investigate nitrate reduction in neutral pH phosphate buffer over a series of 3d (Cu, Ni, Ni0.68Cu0.32, Co, Fe, Ti) and 4d
10 (Ag) transition metals (TMs), identifying properties of bulk resting electronic structure (e.g. work function [Φ] and d-band center energy [Ed
]) as descriptors for nitrate reduction Faradaic efficiency and selectivity to ammonium. We frame our discussion of these results within theoretical and empirical literature on hydrogen evolution and nitric oxide adsorption, finding Φ dictates total nitrate reduction Faradaic efficiency while Ed
determines selectivity towards ammonium. Nitrate reduction FE trends with work function, in-line with well-established trends between HER activity and work function. Selectivity towards ammonium increases as Ed
approaches and overcomes the Fermi level, increasing the adsorption energy of nitrate reduction intermediates (such as NO) by decreasing occupation of anti-bonding states.
Electrochemical Nitrate Reduction to Ammonia on Polycrystalline Copper Electrodes in Alkaline Solutions
Authors: Kim Yohan , Shim Minyoung , Byon Hye Ryung 
Published: July 2022

Ammonia has widely utilized as the raw material of fertilizer and feeds in fuel cells and hydrogen storage materials (Orens. S, Proc. Natl. Acad. Sci. U.S.A.
2021,
118 (49)). In general, the Haber-Bosch process has supplied the mass production of ammonia (N2 + H2 → 2NH3). However, this chemical process requires high-temperature and high-pressure conditions to cleave the triple N2 and produces undesired CO2 gas, as CH4 is added for H2 generation. It is attractive to yield ammonia in milder conditions and more cost-effective methods. In addition, the usage of waste and eco-poisoned species, which is inevitably produced, is valuable as the reactant. For this purpose, nitrate (NO3
-) conversion using electrochemical methods has drawn attention. Nitrate has a high solubility in aqueous media and better reactivity than N2 gas at ambient temperature and atmospheric conditions. Nonetheless, the nitrate reduction undergoes multiple electron-transfer processes (NO3
- + 8e- + 9H+ → NH3 + 3H2O), causing low ammonia selectivity competing against byproducts such as hydrogen, nitrogen oxides, and hydroxylamine.
Here, I show critical factors determining the conversion selectivity of nitrate using Cu catalysts. I prepared three Cu foils treated by different surface cleaning processes. Surface morphology and roughness of Cu relying on the surface treatments significantly altered the conversion efficiency. In particular, nitric oxide (NO) was a pivotal intermediate to determine the final products, which was sensitive to the Cu surface condition. I will discuss details of the electrochemical nitrate reduction process observed by in-situ and ex-situ gas and spectroscopic analyses and correlate the conversion efficiency with the surface conditions of Cu foils.

Figure 1
(Digital Presentation) Electrochemical Recovery of Ammonium and Phosphate from Municipal Wastewater Sources: Kinetics and Water Chemistry
Authors: Greenlee Lauren F , Kekedy-Nagy Laszlo , English Leah , Anari Zahra , Abolhassani Mojtaba , Pollet Bruno Georges , Popp Jennie 
Published: July 2022

Water contamination is ubiquitous and persists across our water resources and supply. Much attention is given to newly identified and emerging contaminants, but we also struggle to successfully mitigate “old”, or well-known, contaminants, which have included ammonia, nitrate, and, more recently, phosphate in municipal wastewaters. However, these compounds are also critical nutrients used to support the global industrialized agriculture sector. Phosphate is of particular importance and concern because phosphate-based fertilizers are currently produced through the mining of phosphate rock, a limited resource mineral. The world’s known available supply of phosphate rock is predicted to become limited within the range of 30 – 200 years, and the flow of phosphorus through the agricultural food cycle is unidirectional, with large portions of mined phosphorus ending up in the environment and landfill. Ammonia is produced for fertilizer and other chemical uses via the Haber-Bosch process, which, annually, uses 2% of global fossil fuel energy demand and contributes 450 M metric tons of CO2 to global emissions. Meanwhile, the technical treatment train for municipal wastewater treatment facilities targets removal of ammonia and phosphate as contaminants, enabling this one-way flow of nutrients from mineral sources and energy-intensive processes through food to waste. This scenario is no longer tenable as we face limited phosphorus world-wide, as well as energy and food security challenges.
In our research, we focus on a magnesium anode-based electrochemical system for the precipitation and recovery of ammonium and phosphate nutrients from municipal wastewater sources. In this study, we have evaluated four different natural wastewater sources, three municipal and one industrial meat processing source to understand how differences in wastewater source water composition affect phosphate and ammonium recovery, and inversely, how the electrochemical treatment process affects resulting wastewater chemistry post-treatment. In this talk, I will discuss our recent results that have shown that phosphate removal kinetics are affected by key water chemistry parameters of chloride concentration, ammonium concentration, calcium concentration, and total organic carbon. Phosphate removal through precipitation showed a two-stage kinetic behavior, with a fast kinetic regime prior to 1 min, and a zeroth order rate from 1 min to 30 min. Corrosion rates of the magnesium anode varied over an order of magnitude and are correlated with the differences in water chemistry. Experimental Mg consumption during the electrochemical process is greater than theoretical Mg consumption resulting in an underestimate of costs, highlighting the importance of experimentally-measured Mg consumption as the more appropriate measure of treatment cost.
Investigating the Application of Graphitic Carbon Nitrides as Additives in Proton Exchange Membranes for Fuel Cells
Authors: Smith Keenan , Miller Thomas Samuel , Brett Dan , Foglia Fabrizia 
Published: July 2022

Proton exchange membranes (PEMs) that conduct protons between electrodes, whilst minimizing the transport of reactant molecules are vital components of energy storage and conversion devices, such as fuel cells (FC), electrolysers and redox flow batteries. Despite over half a century of synthetic development, perfluorosulfonic acid membranes, such as Nafion, remain the industry standard. Performance improvements have thus relied on use of additives to improve water retention and proton conductivity. However, understanding the way in which these additives arrange favourably into the phase separated morphology of the polymer structure and positively influence water uptake and proton conductivity has eluded researchers.
Polytriazine imide structured graphitic carbon nitride (PTI) with a graphitic structure of repeating C12N12H3 structural voids is an ideal candidate additive due to its specific size, functional groups, and hydrophilicity.[1] Using neutron scattering we directly revealed the importance of triazine and bridging N-H groups for facilitated water transport through the intralayer voids and speculate their importance in hydrated proton transport.[2]

Herein, ultrasonic spray printing (USP) was used to incorporate PTI nanosheets into the phase separated morphology of Nafion. Fabrication was optimised via PTI wt.% loading and USP fabrication parameters to obtain a high-performance PEM with proton conductivity higher than commercial Nafion at low and high hydration. USP allowed an increased proportion of PTI to be added over conventional solution casting method without deleterious effect of restacking and agglomeration. Neutron reflectivity (NR) and quasi-elastic neutron scattering were used to probe the structure and dynamics of polymer framework, water and ions. Comparison with pure Nafion and other composite materials provided insight into the way in which graphitic additives arrange inside the polymer aggregates and enhance water transport. This work highlights PTI as an effective 2D material for structural tuning of phase separated polymers for contiguous proton and water transport within the semi-crystalline framework, as well as highlighting an experimental approach to reveal nanoscale structure-property relationships.
[1] T. M. Suter, T. S. Miller, J. K. Cockcroft, A. E. Aliev, M. C. Wilding, A. Sella, F. Corà, C. A. Howard, P. F. McMillan, Chem. Sci., 2019, 10, 2519-2528
[2] F. Foglia, A. J. Clancy, J. Berry-Gair, K. Lisowska, M. C. Wilding, T. M. Suter, T. S. Miller, K. Smith, F. Demmel, M. Appel, V. G. Sakai, C. A. Howard, M. Tyagi, F. Coràand, and P. F. McMillan, Sci. Adv., 2020, 6, eabb6011