bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Electrocatalytic Conversion of CO2 to Syngas with Controlled CO/H2 Ratios
Authors: Chen Jingguang G 
Published: September 2023

One of the main research challenges for electrocatalysis that produces carbon-containing products from CO2 is avoiding the competing hydrogen evolution reaction. Instead of totally eliminating hydrogen, our approach makes use of the readily available protons in aqueous electrolyte to co-produce CO and H2, making synthesis gas (syngas) with a tunable CO:H2 ratio. The resulting syngas can then be used as feedstock for existing thermocatalytic processes, such as Fischer–Tropsch and methanol synthesis reactions [1]. We will present our results in identifying palladium hydride (PdH), formed under electrocatalytic reaction conditions, as an effective electrocatalyst that enables the syngas production [2]. We will also report our efforts in reducing the loading of Pd by alloying Pd with inexpensive secondary metals, supporting Pd on transition metal carbides and nitrides, and utilizing single atom Pd catalysts. For each type of the catalysts, we monitor the phase transition from Pd to PdH under reaction conditions with in-situ synchrotron-based X-ray absorption and X-ray diffraction techniques. We also identify descriptors for syngas production on PdH, bimetallic PdH, and supported PdH catalysts by performing DFT calculations of the effect of PdH formation on the binding strength of reaction intermediates. The research methodology established here should be useful not only for continued optimization of Pd-based syngas-producing electrocatalysts, but also for enhancing activity while reducing the loading of precious metals for other electrocatalytic applications. Furthermore, we will discuss our recent results in utilizing a tandem scheme of electrocatalytic-thermocatalytic processes to convert CO2 to C3 oxygenates [3].
[1] B.M. Tackett, E. Gomez and J.G. Chen, “Net reduction of CO2 via its thermocatalytic and electrocatalytic transformation reactions in standard and hybrid processes”, Nature Catalysis, 2 (2019) 381.
[2] B.M. Tackett, J.H. Lee and J.G. Chen, “Electrochemical Conversion of CO2 to Syngas with Palladium-Based Electrocatalysts”, Accounts of Chemical Research, 53 (2020) 1535.
[3] A.N. Biswas, Z. Xie, R. Xia, S. Overa, F. Jiao and J.G. Chen, “Tandem Electrocatalytic-Thermocatalytic Reaction Scheme for CO2 Conversion to C3 Oxygenates”, ACS Energy Letters, 7 (2022) 2904
(Invited) Carbon Nitride Layers As Light-Harvesting Semiconductors for Photoelectrochemical Cells
Authors: Shalom Menny 
Published: September 2023

Photoelectrochemical cells (PECs) have been developed as environmentally friendly systems that can directly utilize photogenerated electron-hole pairs for water splitting, fuel production, conversion of carbon dioxide, and pollutant degradation. Most reports on the photocatalytic or PEC hydrogen (H2) evolution via water splitting have focused on the H2 reduction half-reaction by generating on the photoanode oxygen or using sacrificial agents to consume the generated h+. Lately, much effort has been invested into synthesizing valuable chemicals on the photoanode while retaining the production of H2 on the cathode.
Over the past few years, polymeric carbon nitrides (CN) have attracted widespread attention due to their outstanding electronic properties, which have been exploited in various applications, including photo- and electro-catalysis, heterogeneous catalysis, CO2 reduction, water splitting, light-emitting diodes, and PV cells. CN comprises only carbon and nitrogen, and it can be synthesized by several routes. Its unique and tunable optical, chemical, and catalytic properties, alongside its low price and remarkably high stability to oxidation (up to 500 °C), make it a very attractive material for photoelectrochemical applications. However, few reports regarded CN utilization in PECs due to the difficulty in acquiring a homogenous CN layer on a conductive substrate and our lack of a basic understanding of the intrinsic layer properties of CN.
This talk will introduce new approaches to growing CN layers with altered properties on conductive substrates for photoelectrochemical applications. The growth mechanism and their chemical, photophysical, electronic, and charge transfer properties will be discussed. I will show the utilization of PEC with a CN-based photoanode as a stable and efficient platform for the oxidation of water or organic molecules to oxygen or added-value chemicals, respectively, with hydrogen co-production.
(Invited) Hybrid Mixed-Metal-Oxide-Based Catalytic Systems for Efficient Electroreduction of Carbon Dioxide
Authors: Kulesza Pawel J. , Rutkowska Iwona A. 
Published: September 2023

Of particular interest to the preparation of advanced catalytic materials is efficient utilization of nanosized materials with well-defined composition, structure and thickness that exhibit desirable electrocatalytic properties. There has been growing interest in the electrochemical conversion of carbon dioxide (a potent greenhouse gas and a contributor to global climate change) to useful carbon-based fuels or chemicals. Given the fact that the CO2 molecule is very stable, its electroreduction processes are characterized by large over-potentials. It is often postulated that, during electroreduction, the rate limiting step is the protonation of the adsorbed CO product to form the CHO adsorbate. In this respect, the proton availability and its mobility at the electrochemical interface has to be addressed. On the other hand, competition between such parallel processes as hydrogen evolution and carbon dioxide reduction has also to be considered.
We explore here the ability of polynuclear transition metal oxide based systems to function as cocatalysts and to stabilize and activate metal nanocenters. Here certain nanostructured metal oxides of zirconium, titanium, molybdenum or tungsten have been demonstrated to influence supported catalytic metal sites in ways other than simple dispersion over electrode area. Evidence is presented that the support can modify activity (presumably electronic nature) of catalytic metal nanoparticles (e.g. Cu, Ru), thus affecting their chemisorptive and catalytic properties during CO2-reduction. Metal oxide (WO3, MoO3, TiO2) nanostructures can generate highly reactive –OH groups at electrocatalytic interface.
Evidence is presented that the support can modify activity (presumably electronic nature) of catalytic metal nanoparticles (e.g. Cu, Pd), thus affecting their chemisorptive properties. Metal oxide (ZrO2, WO3) nanospecies can generate –OH groups at electrocatalytic interface. Our electrocatalytic results with copper nanostructures over-coated with ZrO2 or WO3 nanostructures imply the systems’ improved selectivity toward CO2-reduction relative to the competitive hydrogen evolution as well as the lower tendency of copper sites to undergo poisoning.
(Digital Presentation) Hydrothermal Electrodeposition of Molybdenum Sulfide Toward Electrochemical CO2 Reduction Catalysts
Authors: Yamaguchi Akira 
Published: September 2023

The search and development of efficient carbon dioxide (CO2) reduction reaction electrocatalysts is a hot topic in this era of global warming. Among material candidates for sustainable and cost−effective applications, metal sulfides have attracted attention as promising nature-inspired materials due to multiple adsorption sites which are enhanced by the covalent character of sulfur.
Molybdenum sulfides (MoS2) is one of the trandition metal dichalcogenides (TMDs) and possesses three kinds of struture; namely, metastable octahedral structure with high electronic conductivity (1T), stable triangular prism structure with low electronic conductivity (2H) and insulating rhombohedral structure (3R). Among them, 1T phase has been widely applied as catalysts for various reactions such as electrochemical nitrogen reduction reaction and electro/photochemical hydrogen evolution reaction. Since the structure of MoS2 largely affect its catalytic and other material property, synthetic process to control their bulk and even local structure should be explored to expand their availability as functional materials. Especially, our previous work (J. Phys. Chem.C, 126, 2772, 2022) demonstrated that metal-sufur bonding length is one of the key parameter to control carbon monoxide production selectivity from electrochemical CO2 reduction.
Here in this work, hydrothermal electrodeposition was applied to MoS2 synthesis to control their local structure. Recently, our group developed hydrothermal electrochemical flow reactor which enables the electrochemistry under hydrothermal condition with separate control of temperature and pressure. Using this reactor, hydrothermal electrodeposition of manganese oxides (MnO2) was conducted and samples exhibited higher electrochemical oxygen evolution activity than ones prepared with conventional methods. Also, the characterization results of electrodeposited MnO2 under hydrothermal condition showed the possiblity that morphology and lattice spacing can be controled by changing deposition temperature and pressure, respectively. Thus, we predicted our hydrothermal electrodeposition technique is useful to control the local structure of materials.
The hydrothermal electrodeposition of MoS2 were conducted under various temperature and pressure conditions and those samples were characterized with X-ray diffraction (XRD). Also, the effect of the deposition temperature and pressure on sample local structure was examined with Pair Disribution Function analysis of XRD and Extended X-ray Absorption Fine Structure analysis using synchrotron radiation. The electrochemical CO2 reduction experiments using hydrothermally depositted MoS2 samples revealed that the product selectivity for CO2 reduction was changed with deposition pressure. Thus, we confirmed that our hydrothermal electrochemical deposition can be applicable to the synthesis of metal sulfide-based CO2 reduction electrocatalysts, whose local structures are tuned.
Modeling the Coulombic Efficiency of the Aqueous Iron Electrode
Authors: Thomas-Alyea Karen 
Published: September 2023

The aqueous iron electrode is attractive for large-scale energy storage because of its long life and low materials cost. The redox potential of the Fe ↔ Fe2+ reaction is approximately 50 mV negative of that of the hydrogen evolution reaction. Hydrogen evolution therefore causes self discharge of the iron electrode during rest and competes with the iron reaction during charge. Here we model the effect of electrode design and cell operation on the coulombic efficiency of charging the iron electrode at modest charging rates (<C/20). Kinetic parameters (exchange current density and transfer coefficients) for the iron dissolution-precipitation reaction and for the hydrogen evolution reaction are estimated from experimental measurements of electrode overpotential and hydrogen generation rate. The volume change from Fe(OH)2 to Fe metal results in a significant increase in porosity during charge and results in change in electrochemically active surface area. The porous-electrode model includes transport in the electrolyte, Butler-Volmer kinetics, and change in volume and surface area.
The model provides a theoretical explanation for experimental observations that coulombic efficiency decreases with decreasing charge rate, and that coulombic efficiency is lower in thicker electrodes. We then use the model to explore the impact for large-format cells of electrode size and design on coulombic efficiency.
Proton Activity and Pathway in Aqueous Organic Redox Flow Batteries
Authors: Wang Wei 
Published: September 2023

Aqueous soluble organic (ASO) redox-active materials have recently shown great promise as alternatives to transition metal ions employed as energy-bearing active materials in redox flow batteries for large-scale energy storage because of their structural tunability, cost-effectiveness, availability, and safety features. However, development so far has been limited to a small palette of organics that are aqueous soluble. This presentation will use fluorenone as an example to showcase how a natively redox-inactive molecule can be tuned to possess two-electron redox reversibility through hydrogenation and dehydrogenation. The modified fluorenone molecules demonstrated high energy density and recorded stable cycling. Furthermore, research has shown the kinetics of the redox reactions; thus, the system rate capabilities can be improved by incorporating suitable hydrogen acceptors that regulate the proton pathway for a faster redox reaction.
Reference: Feng et al., Science 372, 836–840 (2021), Feng et al., submitted, 2022
Understanding Capacity Fade in Organic Redox-Flow Batteries by Combining Spectroscopy with Statistical Inference Techniques
Authors: Modak Sanat Vibhas , Shen Wanggang , Herrera Dylan , Goldsmith Bryan R. , Huan Xun , Kwabi David G. 
Published: September 2023

Aqueous-soluble organic and organometallic redox-active molecules show considerable promise as redox-flow battery (RFB) reactants because their costs at scale are projected to be low. However, most aqueous organic RFB undergo rapid degradation resulting in high rates of capacity fade. Considerable research has been devoted towards discovering chemically stable charge carriers for RFBs. However, the decomposition mechanisms of underperforming chemistries during flow cell cycling are often poorly understood, and in some instances, competing or incompatible hypotheses about the relationship between reactant decay and capacity fade have often been proposed.
In this talk, we will demonstrate that combining spectroscopic and statistical inference techniques can be used to shed light on relationship between RFB reactant degradation and capacity fade. Specifically, we employ in operando ultraviolet-visible spectrophotometry along with Bayesian inference, Bayesian model selection, and multivariate curve regression in order to quantify the relative probabilities of different decay mechanisms given the data at hand, and to estimate rate constants for specific reactions within the most probable decay scheme. In principle, rate constants thus obtained can be fed into a zero-dimensional electrochemical flow cell model, recently developed by our group, that can simulate capacity fade given a reactant decay mechanism, associated rates, and the cycling protocol. This work has the potential to shed light on the relationship between capacity fade and reactant decay in various organic RFB chemistries, and to enable prediction of the lifetimes of commercial-scale RFBs.
Sodium Metal Hybrid Redox Flow Batteries Containing Sulfide and Thiophosphate Catholytes
Authors: Self Ethan , Lehmann Michelle , Yang Guang 
Published: September 2023

Energy storage systems which meet the requirement for long-duration energy storage (LDES) are critical to enable widespread adoption of intermittent renewables (e.g., solar and wind) on the electric grid. DOE’s Long Duration Storage Shot has set an ambitious goal of reducing energy storage costs ≥90% by 2030. To address this challenge, the proposed work is aimed at developing low-cost, high-energy redox flow batteries (RFBs) based on earth-abundant active materials.
Prior work on room temperature Na2Sx catholytes demonstrated outstanding reversibility and cycling stability in batch and flow cell configurations (e.g., reversible capacities ~200 mAh/gS with negligible fade over 250 cycles and several months of continuous testing). While precipitation of low-order polysulfides (x≤4) during discharge doesn’t negatively impact the performance of lab-scale prototypes, these ionically/electronically insulating species will present major challenges for system scaleup (e.g., inhibited charge transfer due to current collector passivation). As such, the practical cycling window of Na2Sx is restricted to soluble species (5≤x≤8) with a sulfur utilization of 125 mAh/gS.
To improve the viability of room temperature Na/Na2Sx RFBs, our team recently discovered that the addition of P2S5 greatly increases the solubility of low-order sodium polysulfides through formation of previously unknown Na-P-S solvated complexes. This general class of sodium thiophosphates has tremendous, untapped potential for next-generation nonaqueous catholytes and can potentially enable reversible Na capacities exceeding 1,000 mAh/g. This presentation will describe ongoing efforts aimed at: (i) assessing key properties (electrochemical reversibility, solubility, chemical stability) of sodium thiophosphates in nonaqueous electrolytes, (ii) benchmarking the performance of lab-scale RFB prototypes containing Na-P-S catholytes and ceramic membranes, and (iii) quantifying voltage losses on electrodes polarized far from equilibrium using 3 electrode AC impedance measurements.

Acknowledgements

This research was conducted at Oak Ridge National Laboratory, managed by UT Battelle, LLC, for the U.S. Department of Energy (DOE) and is sponsored by the U.S. Department of Energy through the Energy Storage Program in the Office of Electricity.
(Invited) High-Rate and High-Efficiency Molten Salt Li-O2 and Na-O2 Batteries Enabled by Nitrate Redox
Authors: Leverick Graham , Zhu Yunguang , Shao-Horn Yang 
Published: September 2023

The decarbonization of the electrical grid requires advancements in affordable, long-term energy storage to address the intermittency of energy sources like solar and wind, while the continued decarbonization of the transportation sector necessitates advancements in energy dense storage devices such as batteries, with low cost and made from abundant materials. Alkali metal-oxygen batteries can provide greater specific energy than Li-ion batteries and can potentially lower cost by reducing reliance on late transition metals like nickel and cobalt. In this talk, we share our recent work on molten-salt Li-O2
1 and Na-O2
2 batteries operating at 150-170 °C which can deliver high areal energy (33 mWh/cm2
geo) and power densities (19 mW/cm2
geo), with high energy efficiency (~90% at 5 mA/cm2
geo). We show that nitrate redox plays a critical role in these batteries, where the apparent four-electron oxygen reduction to form Li2O in Li-O2 batteries is facilitated by the electrochemical reduction of nitrate to nitrite, and subsequent chemical oxidation of nitrite to nitrate by molecular oxygen. In Na-O2 batteries, on the other hand, Na2O is further oxidized by O2 to Na2O2 to give an apparent two-electron oxygen reduction rection. We demonstrate the role of transition metal oxide catalysts for reducing the overpotential of nitrate redox in the positive electrode, as well as strategies for enhancing the power density and specific energy of these molten-salt metal-oxygen batteries.

References

(1) Zhu, Y. G.; Leverick, G.; Giordano, L.; Feng, S.; Zhang, Y.; Yu, Y.; Tatara, R.; Lunger, J. R.; Shao-Horn, Y. Nitrate-Mediated Four-Electron Oxygen Reduction on Metal Oxides for Lithium-Oxygen Batteries. Joule
2022, 6 (8), 1887–1903.
(2) Zhu, Y. G.; Leverick, G.; Accogli, A.; Gordiz, K.; Zhang, Y.; Shao-Horn, Y. A High-Rate and High-Eﬃciency Molten-Salt Sodium–Oxygen Battery. Energy Env. Sci
2022, 15, 4636–4646.
Cation Modified Highly Soluble Active Materials for Redox Flow Batteries
Authors: Pahari Shyam K , Gokoglan Tugba Ceren , Bolibok Jennifer Nina , Cappillino Patrick J. , Agar Ertan 
Published: September 2023

Renewables such as solar and wind energy are making increased penetration into modern electrical grids.1 However, the reliability of such grids is challenged by the intermittent nature of renewable sources and variable atmospheric conditions, posing a major roadblock in transition toward carbon-neutral energy sources. Grid level energy storage has long been seen as a solution to the intermittency problem.2 Among various storage technologies, redox flow batteries (RFBs) stand out, due to their ability to accommodate various needs of renewable-powered grids.3 RFBs based on non-aqueous chemistry (NRFBs) have a potential to greatly increase the energy density, however, a major setback in NRFB implementation arises from instability and low solubility of active materials.4,5

Herein, we present a strategy to design a flow battery utilizing anionic active materials which exhibit high solubility and high stability. To this end, we utilized a highly stable bio-inspired complex, vanadium-bis-hydroxyiminodiacetate (VBH) as a catholyte and anthraquinone-sulfonate (AQS) as an anolyte scaffold. Cycling performance of a flow battery based on VBH/AQS active materials was investigated in a full cell and a detailed chemical and electrochemical analysis of electrolytes before and after cycling was performed. Post-cycling analysis of electrolyte revealed that the active materials are highly stable even under deep charge-discharge cycling. However, lack of suitable membrane resulted in modest capacity fade. To overcome the crossover issue, a full cell comprising compositionally symmetric electrolytes, made by mixing anolyte and catholyte, was performed and various performance metrics of such cell were evaluated.

References:

(1) International Energy Agency. Global Energy Review 2021; Paris https://www.iea.org/reports/global-energy-review-2021, License: CC BY 4.0.
(2) Albertus, P.; Manser, J. S.; Litzelman, S. Long-Duration Electricity Storage Applications, Economics, and Technologies. Joule
2020, 4 (1), 21–32. https://doi.org/10.1016/j.joule.2019.11.009.
(3) Dunn, B.; Kamath, H.; Tarascon, J.-M. Electrical Energy Storage for the Grid: A Battery of Choices. Science
2011, 334 (6058), 928–935. https://doi.org/10.1126/science.1212741.
(4) Pahari, S. K.; Gokoglan, T. C.; Visayas, B. R. B.; Woehl, J.; Golen, J. A.; Howland, R.; Mayes, M. L.; Agar, E.; Cappillino, P. J. Designing High Energy Density Flow Batteries by Tuning Active-Material Thermodynamics. RSC Advances
2021, 11 (10), 5432–5443. https://doi.org/10.1039/D0RA10913D.
(5) Sánchez-Díez, E.; Ventosa, E.; Guarnieri, M.; Trovò, A.; Flox, C.; Marcilla, R.; Soavi, F.; Mazur, P.; Aranzabe, E.; Ferret, R. Redox Flow Batteries: Status and Perspective towards Sustainable Stationary Energy Storage. Journal of Power Sources
2021, 481, 228804. https://doi.org/10.1016/j.jpowsour.2020.228804.

Figure 1