Unlocking solar power: transforming CO₂ into valuable formate

In a significant advance for sustainable energy, scientists have developed a new method to convert carbon dioxide (CO₂) into formate, a valuable chemical, through a solar-driven process. This innovative approach boosts both the efficiency and selectivity of CO₂ conversion, presenting a dual solution for renewable energy utilization and reducing greenhouse gas emissions.

As the impacts of climate change grow more urgent, the need for effective carbon capture and utilization has become paramount. Among the various strategies, electrochemical converting carbon dioxide (CO₂) reduction offers a promising way to convert CO₂ into useful fuels or chemicals at ambient temperatures. However, existing methods often struggle with poor selectivity and competition from hydrogen evolution reactions, limiting their efficiency. Overcoming these challenges requires the development of new catalysts that can significantly enhance the conversion process, making this field become a critical area for research.

This new study (DOI: 10.1016/j.esci.2024.100246), conducted by researchers from the International Research Center for Renewable Energy at Xi’an Jiaotong University, was published in eScience on February 2, 2024. The research highlights the development of an indium-based heterojunction (i.e., In/In₂O₃) catalyst that enhances formate production through a synergistic effect of oxygen species and vacancies. By improving both the efficiency and selectivity of the reaction, the study marks a significant step forward in the field of CO₂ electroreduction.

The research team designed the In/In₂O₃ heterojunction catalyst with varying levels of oxygen species and vacancies, crucial factors in the improved performance. Using in situ surface-enhanced Raman spectroscopy (SERS), the team confirmed that the catalyst followed the *COOH pathway, which was highly selective for formate production. Theoretical models revealed that the energy barrier for *COOH formation decreased significantly in the presence of oxygen vacancies, achieving over 90% formate selectivity. When powered by photovoltaics, the system reached a solar-to-fuel efficiency of 10.11%, outperforming previous technologies. This high efficiency underscores the catalyst’s potential for future applications in renewable energy systems, particularly in electrochemical CO₂ reduction.

Professor Liejin Guo (Academician of the Chinese Academy of Sciences), the lead researcher, commented on the breakthrough, saying, “Our research demonstrates a critical advancement in CO₂ reduction technology. The synergy between oxygen species and vacancies in our novel catalyst has led to a dramatic increase in both selectivity and efficiency. This paves a way for practical applications in sustainable energy conversion.”

The potential applications of this research are vast, especially in the renewable energy sector. The ability to efficiently convert CO₂ into formate could lead to the development of more sustainable energy systems, decreasing dependence on fossil fuels. Additionally, the use of solar energy to drive the reaction suggests that this technology could seamlessly integrate with existing renewable infrastructures, offering a promising future for carbon recycling initiatives.

eScience – a Diamond Open Access journal (free for both readers and authors before 2026) cooperated with KeAi and published online at ScienceDirect. eScience is founded by Nankai University and aims to publish high-quality academic papers on the latest and finest scientific and technological research in interdisciplinary fields related to energy, electrochemistry, electronics, and environment. eScience has been indexed by ESCI, CAS, DOAJ and Scopus. The First Impact Factor (2023) is 42.9. The founding Editor-in-Chief is Professor Jun Chen from Nankai University. He is an academician of the Chinese Academy of Sciences, a fellow of The World Academy of Sciences. eScience has published 19 issues, which can be viewed at https://www.sciencedirect.com/journal/escienc

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