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3. The 2022 solar fuels roadmap

Author

Segev, Gideon, Kibsgaard, Jakob, Hahn, Christopher, Xu, Zhichuan J, Cheng, Wen-Hui, Deutsch, Todd G, Xiang, Chengxiang, Zhang, Jenny Z, Hammarström, Leif, Nocera, Daniel G, Weber, Adam Z, Agbo, Peter, Hisatomi, Takashi, Osterloh, Frank E, Domen, Kazunari, Abdi, Fatwa F, Haussener, Sophia, Miller, Daniel J, Ardo, Shane, McIntyre, Paul C, Hannappel, Thomas, Hu, Shu, Atwater, Harry, Gregoire, John M, Ertem, Mehmed Z, Sharp, Ian D, Choi, Kyoung-Shin, Lee, Jae Sung, Ishitani, Osamu, Ager, Joel W, Prabhakar, Rajiv Ramanujam, Bell, Alexis T, Boettcher, Shannon W, Vincent, Kylie, Takanabe, Kazuhiro, Artero, Vincent, Napier, Ryan, Cuenya, Beatriz Roldan, Koper, Marc TM, Van De Krol, Roel, and Houle, Frances

Subjects
Engineering, Materials Engineering, Responsible Consumption and Production, Affordable and Clean Energy, Climate Action, solar fuels, catalysis, CO2 reduction, water splitting, Physical Sciences, Applied Physics, Physical sciences
Abstract

Renewable fuel generation is essential for a low carbon footprint economy. Thus, over the last five decades, a significant effort has been dedicated towards increasing the performance of solar fuels generating devices. Specifically, the solar to hydrogen efficiency of photoelectrochemical cells has progressed steadily towards its fundamental limit, and the faradaic efficiency towards valuable products in CO2 reduction systems has increased dramatically. However, there are still numerous scientific and engineering challenges that must be overcame in order to turn solar fuels into a viable technology. At the electrode and device level, the conversion efficiency, stability and products selectivity must be increased significantly. Meanwhile, these performance metrics must be maintained when scaling up devices and systems while maintaining an acceptable cost and carbon footprint. This roadmap surveys different aspects of this endeavor: system benchmarking, device scaling, various approaches for photoelectrodes design, materials discovery, and catalysis. Each of the sections in the roadmap focuses on a single topic, discussing the state of the art, the key challenges and advancements required to meet them. The roadmap can be used as a guide for researchers and funding agencies highlighting the most pressing needs of the field.

Published
2022

13. High-Pressure oxidative coupling of methane on alkali metal catalyst – Microkinetic analysis and operando thermal visualization

Author

Yu, Yuhang (author), Obata, Keisuke (author), Movick, William J. (author), Yoshida, Shintaro (author), Palomo Jiménez, J. (author), Lundin, Sean Thomas B. (author), Urakawa, A. (author), Sarathy, S. Mani (author), Takanabe, Kazuhiro (author), Yu, Yuhang (author), Obata, Keisuke (author), Movick, William J. (author), Yoshida, Shintaro (author), Palomo Jiménez, J. (author), Lundin, Sean Thomas B. (author), Urakawa, A. (author), Sarathy, S. Mani (author), and Takanabe, Kazuhiro (author)

Abstract

To introduce promotional H2O effects for both CH4 rate and C2 selectivity, the OH radical formation, catalyzed through H2O activation with O2 surface species, was critical for modeling selective Mn-K2WO4/SiO2 catalysts. Based on our reported experimental evidence, which demonstrates the formation of H2O2 through surface alkali peroxide intermediate, the elementary reactions that account for the OH-mediated pathway were added into the microkinetic model. The advanced model adeptly replicated the promotional H2O effects on both OCM rate and selectivity. The data from a low-pressure microkinetic study were treated isothermally, and extended for near-industrially relevant pressures up to 901 kPa. Thermal visualization using an infrared camera found substantial temperature increases at undiluted high-pressure conditions which caused C2 selectivity to drop significantly. When the furnace temperatures were decreased after ignition, side reactions after O2 depletion (e.g., hydrocarbon reforming) were suppressed, obtaining 13.7 (11.8) % yields at 19.9 % CH4 conversion with 68.6 (59.1) % selectivities for C2-4 (C2) at 901 kPa. The temperature was found to be the determining factor of C2 yield which was perturbed by varying space velocity or CH4/O2 ratios. The optimum temperature for high-pressure conditions was predicted as 885 °C at 901 kPa. The study provides mechanistic and industrially relevant understandings for further OCM catalyst design and system application., ChemE/Catalysis Engineering

Published
2024
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45. High current density microkinetic and electronic structure analysis of CO2reduction using Co and Fe complexes on gas diffusion electrode

Author

Lu, Xiaofei, Dereli, Busra, Shinagawa, Tatsuya, Eddaoudi, Mohamed, Cavallo, Luigi, and Takanabe, Kazuhiro

Abstract

Reaction mechanisms of electrocatalytic CO2reduction into CO over Co or Fe complexes were examined using gas diffusion electrodes to meet the requirement of high current densities for industrial deployment. Our experimental and theoretical calculation results consistently revealed that the Fe-based molecular catalysts exhibited more positive redox potentials relevant to CO2electrocatalysis but disfavored the desorption of generated CO, especially at high overpotentials, failing to achieve appreciable reaction rates. Distinctively, the heterogenized Co-based molecular complexes were found to be tolerant to the high coverage of CO at steady state on the active site and achieved rates exceeding 100 mA cm−2toward exclusive CO evolution. Density-functional theory calculations not only disclosed the redox non-innocent tetraphenylporphyrins and phthalocyanines during electrocatalytic CO2reduction but also corroborated the energetics, especially for CO2and CO adsorption, accounting for distinctive reaction pathways between Co and Fe complexes.

Published
2022
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50. Electrocatalytic Activity and Stability of M-Fe Catalysts Synthesized by Polymer Complex Method for PEFC Cathode

Author

Ou, Yiwei, Kumagai, Hiromu, Fengxiang, Yin, Okada, Saori, Hatasawa, Haruna, Morioka, Hiroyuki, Takanabe, Kazuhiro, Kubota, Jun, and Domen, Kazunari

Subjects
chemistry.chemical_classification, Materials science, Renewable Energy, Sustainability and the Environment, Inorganic chemistry, Polymer, Condensed Matter Physics, Cathode, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, law.invention, Catalysis, chemistry, law, Materials Chemistry, Electrochemistry
Published
2011

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