Modulating the coordination environment in CeO2-x towards enhanced photocatalytic CO2 conversion stability and performance

In the field of photocatalytic CO₂ conversion, vacancy defect engineering (e.g., oxygen, nitrogen, and sulfur vacancies) has been widely employed to endow semiconductor photocatalysts with unique properties. However, Vo in metal oxides is prone to being filled by atmospheric oxygen, posing a significant challenge to their stability. Consequently, developing effective strategies to stabilize Vo is crucial for their practical application.

  Here, we report a novel strategy to regulate the coordination environment of CeO_2-x via indium (In) doping, which not only successfully mitigates the issue of Vo being easily filled by atmospheric oxygen but also significantly enhances photocatalytic CO₂ conversion performance. Specifically, the introduced In dopants substitute for Ce⁴⁺ ions and form In³⁺–Vo complexes. Comprehensive characterizations, including positron annihilation lifetime spectroscopy (PALS) and X-ray absorption fine structure (XAFS) spectroscopy, verify that these complexes suppress the formation of unstable vacancy clusters, thereby concurrently enhancing the stability of Vo and the catalytic activity.

   This work provides a new perspective for the analysis of Vo stabilization mechanisms and opens up a new avenue for improving catalytic activity and stability by regulating the coordination environment of metal oxides. The related research findings, titled “Modulating the coordination environment in CeO_2-x towards enhanced photocatalytic CO₂ conversion stability and performance”, was published in Advanced Powder Materials (Available online on 17 October 2025).