Reviewed by Lexie CornerOct 30 2024
A research team from the International Research Center for Renewable Energy at Xi’an Jiaotong University recently published a study in eScience. This study presents the development of a heterojunction catalyst based on indium (In/In₂O₃), which improves formate production through the combined effect of oxygen species and vacancies. This advancement boosts both the reaction's efficiency and selectivity, representing a substantial advancement in CO₂ electroreduction.
The diagram illustrates the transition from the OCHO pathway to the COOH pathway in the electrochemical reduction of CO2 to formate (HCOOH) on an In/In₂O₃ heterojunction catalyst. The synergistic effect of oxygen species and vacancies boosts formate productivity and faradaic efficiency, favoring the COOH pathway for improved performance. Image Credit: eScience
With the escalating urgency of climate change impacts, effective carbon capture and utilization have become essential. Electrochemical reduction of carbon dioxide (CO₂) stands out as a promising approach to transform CO₂ into valuable fuels or chemicals at room temperature.
However, current methods often face challenges like low selectivity and competition from hydrogen evolution reactions, which restrict their efficiency. Addressing these issues calls for the creation of novel catalysts capable of substantially improving the conversion process, making this area a key focus of research.
The research team developed the In/In₂O₃ heterojunction catalyst with controlled oxygen species and vacancies, which were essential to its enhanced performance. Using in situ surface-enhanced Raman spectroscopy (SERS), they confirmed that the catalyst operated via the *COOH pathway, showing high selectivity for formate production.
Theoretical modeling indicated that the energy barrier for *COOH formation was substantially reduced in the presence of oxygen vacancies, achieving formate selectivity above 90 %. When powered by photovoltaics, the system achieved a solar-to-fuel efficiency of 10.11 %, surpassing prior technologies. This impressive efficiency highlights the catalyst's potential for renewable energy applications, especially in electrochemical CO₂ reduction.
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.
Liejin Guo, Professor and Lead Researcher, Xi’an Jiaotong University
Liejin Guo is an Academician of the Chinese Academy of Sciences.
This research has extensive potential applications, particularly within the renewable energy sector. Efficiently converting CO₂ into formate could foster the development of more sustainable energy systems, reducing reliance on fossil fuels. Moreover, the use of solar energy to power the reaction indicates that this technology could integrate smoothly with current renewable infrastructures, presenting an encouraging outlook for carbon recycling initiatives.
This research is funded by the National Natural Science Foundation of China, the Natural Science Basic Research Program of Shaanxi, the Key Research and Development Program of Shaanxi, and the Fundamental Research Funds for the Central Universities.
Journal Reference:
Ma, T., et al. (2024) Synergistic effect of oxygen species and vacancy for enhanced electrochemical CO2 conversion to formate on indium oxide. EScience. doi.org/10.1016/j.esci.2024.100246.