@article {1145,
	title = {Operational Limits of Redox Metal Oxides Performing Thermochemical Water Splitting},
	journal = {Energy Technology},
	volume = {10},
	year = {2022},
	pages = {2100222},
	abstract = {Solar thermochemical hydrogen production is an attractive technology that stores intermittent solar energy in the form of chemical bonds. Efficient operation requires the identification of a redox-active metal oxide (MOx) material that can achieve high conversion of water to hydrogen at minimal energy input. Water splitting occurs by consecutive reduction and reoxidation reactions of MOx. MOx is reduced to MOx-δ and, in the second step, is reoxidized by water recovering the initial MOx and generate H2. The material must reduce at temperatures achievable in concentrated solar receiver/reactors, while maintaining a thermodynamic driving force to split water. At equilibrium, extent of reduction depends on temperature and oxygen partial pressure, and in this analysis, a set of thermodynamic properties, namely, enthalpy and entropy of oxygen vacancy formation, is sufficient to represent MOx. Herein, a method to easily classify materials based on these thermodynamic properties under any condition of oxygen partial pressure and temperature is presented. This method is based on fundamental thermodynamic principles and is applicable for any redox material with known thermodynamic properties. Despite the simplicity of the method, it is believed that this analysis will support future research in targeting thermodynamic properties of redox-active metal oxides.},
	keywords = {Hydrogen production, solar energy, thermochemical cycles, thermodynamic properties, water splitting},
	doi = {https://doi.org/10.1002/ente.202100222},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/ente.202100222},
	author = {Bayon, Alicia and de la Calle, Alberto and Stechel, Ellen B. and Muhich, Christopher}
}
@article {1147,
	title = {Redox Defect Thermochemistry of FeAl2O4 Hercynite in Water Splitting from First-Principles Methods},
	journal = {Chemistry of Materials},
	volume = {34},
	year = {2022},
	pages = {519-528},
	keywords = {concentrated solar, Hercynite, hydrogen lcroduction, Perovskite, Redox Defect, screening, thermochemistry, thermogravimetry, water splitting},
	doi = {10.1021/acs.chemmater.1c01049},
	url = {https://doi.org/10.1021/acs.chemmater.1c01049},
	author = {Millican, Samantha L. and Clary, Jacob M. and Musgrave, Charles B. and Lany, Stephan}
}
@article {1150,
	title = {System and technoeconomic analysis of solar thermochemical hydrogen production},
	journal = {Renewable Energy},
	volume = {190},
	year = {2022},
	pages = {294-308},
	abstract = {Hydrogen is a promising energy carrier that can be obtained from various feedstocks using renewable energy sources. Direct solar thermochemical hydrogen (STCH) production by water splitting can utilize the full spectrum of solar radiation and has the potential to achieve high solar energy conversion efficiencies. Currently STCH research areas focus on material discovery. This paper evaluates the performance of various STCH materials in the context of a system platform to assess techno-economic benefits and gaps in the path to STCH scale-up. To analyze the hydrogen production cost, a concentrating solar thermal (CST) system is introduced as a platform for integrating STCH materials and accommodating generalized thermochemical processes. The thermochemical process is based on a two-step STCH cycle using metal oxide that consists of a high temperature step for metal oxide reduction, followed by an oxidation step for water splitting at a lower temperature. A preferred configuration is to have the high temperature step occurring in a directly irradiated solar receiver reactor. To this end, we conceptualized a receiver design and associated solar field layout and investigated STCH operational boundaries, component costs and sensitivity parameters on the $2/kgH2 goal of hydrogen production. The study explored system-related variables and factors associated with scaling up. The CST platform allows more comprehensive studies that encompass aspects of STCH materials and systems such as cost, hydrogen productivity and replacement frequency, alongside other system components like heliostat field, tower, and potential receiver costs.},
	keywords = {H2A analysis, Hydrogen production, Solar receiver, Solar thermochemical hydrogen production, Technoeconomic analysis, water splitting},
	issn = {0960-1481},
	doi = {https://doi.org/10.1016/j.renene.2022.03.108},
	url = {https://www.sciencedirect.com/science/article/pii/S0960148122003925},
	author = {Zhiwen Ma and Patrick Davenport and Genevieve Saur}
}
@article {1133,
	title = {A Thermogravimetric Temperature-Programmed Thermal Redox Protocol for Rapid Screening of Metal Oxides for Solar Thermochemical Hydrogen Production},
	journal = {Frontiers in Energy Research},
	volume = {10},
	year = {2022},
	month = {04},
	pages = {856943},
	keywords = {concentrated solar, hydrogen lcroduction, Perovskite, screening, thermogravimetry, water splitting},
	doi = {10.3389/fenrg.2022.856943},
	author = {Sanders, Michael and Bergeson-Keller, Anyka and Coker, Eric and O{\textquoteright}Hayre, Ryan}
}
@article {1158,
	title = {Influence of Supporting Electrolyte on Hydroxide Exchange Membrane Water Electrolysis Performance: Anolyte},
	journal = {Journal of The Electrochemical Society},
	volume = {168},
	year = {2021},
	month = {08/2021},
	pages = {084512},
	abstract = {Hydroxide-exchange-membrane water electrolysis (HEMWE) is an emerging hydrogen-production pathway that combines many advantages of incumbent alkaline water electrolysis (AWE) and proton-exchange-membrane water electrolysis (PEMWE). Advancement in HEMWE has been accelerated with the development of stable and conductive hydroxide exchange membranes (HEMs) and a more comprehensive understanding of alkaline gas-evolving kinetics. However, performance and durability without supporting electrolytes (SELs) remain inferior to PEMWE and AWE and little is known about the role and impact of the SELs. This study investigates the effects of SELs used as anolyte solutions in HEMWEs including cation-type, anion-type, SEL conductivity and pH, presence of carbonates and increased cation/OH- ratios on cell voltage and stability. We report our findings that (i) cell potential and high-frequency resistance did not correlate with anolyte SEL conductivity, (ii) cation-type influences cell voltage at low current densities (<50 mA cm-2) as predicted by half-cell measurements, (iii) increased cation/OH- ratio causes increased overpotentials, and (iv) carbonates are exchanged in the HEM but removed via self-purging at high current density. Overall, this study concludes that concentrated KOH is still the best SEL.},
	keywords = {hydrogen production pathway, Hydroxide exchange membrane, incumbent alkaline, proton exchange membrane, supporting electrolytes, water electrolysis},
	doi = {10.1149/1945-7111/ac1dcd},
	url = {https://doi.org/10.1149/1945-7111/ac1dcd},
	author = {Aleksandr Kiessling and Julie C. Fornaciari and Grace Anderson and Xiong Peng and Andreas Gerstmayr and Michael R. Gerhardt and Samuel McKinney and Alexey Serov and Yu Seung Kim and Barr Zulevi and Adam Z. Weber and Nemanja Danilovic}
}
@article {1159,
	title = {Layer-structured triple-conducting electrocatalyst for water-splitting in protonic ceramic electrolysis cells: Conductivities vs. activity},
	journal = {Journal of Power Sources},
	volume = {495},
	year = {2021},
	pages = {229764},
	abstract = {Electron, proton and oxygen-triple-conducting materials are becoming the dominant steam electrode candidate to break the rate limit on the water-splitting reaction that throttles the performance of protonic ceramic electrolysis cells (PCECs). In this study, based on Pr2NiO4+δ Ruddlesden-Popper phase, we manipulate these conductivities by Pr-site Ba substitution to probe the correlation of each conductivity with the kinetics of the elementary reaction steps. It is found that the proton conductivity is vital to sustain an extended active surface area for faster adsorption of reactants and desorption of products. The effect of oxygen conductivity is surprisingly found insignificant in the water-splitting reaction. On the contrary, surface oxygen removal is discovered as the most rate-limiting process. The electronic conductivity is not a direct limiting factor. However, an electron transfer process between the current collector and the electrode junction could introduce extra resistance that is perceptible at a high operating temperature range. The best water-splitting activity is obtained on a proton conductivity/oxygen surface desorption capability well-balanced sample after Ba substitution. As a result, a water-splitting reaction resistance of 0.022 Ωcm2, a current density of 1.96 A/cm2 at 700~{\textdegree}C is achieved on Pr1.7Ba0.3NiO4+δ, one of the best performances for PCECs.},
	keywords = {Hydrogen generation, Protonic ceramic electrolysis cells, Ruddlesden-popper phase, Triple-conducting electrocatalyst, Water-splitting},
	issn = {0378-7753},
	doi = {https://doi.org/10.1016/j.jpowsour.2021.229764},
	url = {https://www.sciencedirect.com/science/article/pii/S0378775321003050},
	author = {Wenyuan Li and Bo Guan and Tao Yang and Zhongqiu Li and Wangying Shi and Hanchen Tian and Liang Ma and Thomas L. Kalapos and Xingbo Liu}
}
@article {1170,
	title = {Emergent Degradation Phenomena Demonstrated on Resilient, Flexible, and Scalable Integrated Photoelectrochemical Cells},
	journal = {Advanced Energy Materials},
	volume = {10},
	year = {2020},
	pages = {2002706},
	abstract = {Abstract Photoelectrochemical (PEC) water splitting provides a pathway to generate sustainable clean fuels using the two most abundant resources on Earth: sunlight and water. Currently, most of the successful models of PEC cells are still fabricated on small scales near 1 cm2, which largely limits the mass deployment of solar-fuel production. Here, the scale-up to 8 cm2 of an integrated PEC (IPEC) device is demonstrated and its performance compared to a 1 cm2 IPEC cell, using state-of-the-art iridium and platinum catalysts with III{\textendash}V photoabsorbers. The initial photocurrents at 1 sun are 8 and 7 mA cm-2 with degradation rates of 0.60 and 0.47 mA cm-2 day-1, during unbiased operation for the 1 and 8 cm2 devices, respectively. Evaluating under outdoor and indoor conditions at two U.S. National Laboratories reveals similar results, evidencing the reproducibility of this design{\textquoteright}s performance. Furthermore, the emerging degradation mechanisms during scale-up are investigated and the knowledge gained from this work will provide feedback to the broader community, since PEC device durability is a limiting factor in its potential future deployment.},
	keywords = {durability, on-sun testing, PEC cell scale-up, reproducibility, water splitting},
	doi = {https://doi.org/10.1002/aenm.202002706},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/aenm.202002706},
	author = {Kistler, Tobias A. and Zeng, Guosong and Young, James L. and Weng, Lien-Chun and Aldridge, Chase and Wyatt, Keenan and Steiner, Myles A. and Solorzano Jr., Oscar and Houle, Frances A. and Toma, Francesca M. and Weber, Adam Z. and Deutsch, Todd G. and Danilovic, Nemanja}
}
