The Electron Transport Regulation in Carbon Dots/In<sub>2</sub>O<sub>3</sub> Electrocatalyst Enable 100% Selectivity for Oxygen Reduction to Hydrogen Peroxide
Jie Wu, Yidong Han, Yuchen Bai, Xiting Wang, Yunjie Zhou, Wenxiang Zhu, Tiwei He, Yingming Wang, Hui Huang, Yang Liu, Zhenhui Kang
Abstract
Abstract Direct electrosynthesis of hydrogen peroxide (H 2 O 2 ) via two‐electron pathway oxygen reduction reaction (2e − ORR) is crucially essential for a sustainable green economy. However, catalysts inevitably undergo four‐electron pathway oxygen reduction reaction (4e − ORR), resulting in low selectivity and economic benefits. The current challenge is to provide a feasible design strategy for obtaining satisfactory 2e − ORR catalysts with high selectivity. In this work, carbon dots (CDs) act as a cocatalyst to regulate the electron transport kinetics of In 2 O 3 /CDs, and the influence of CDs on the ORR pathways of In 2 O 3 /CDs is also studied. The electron transfer kinetics on In 2 O 3 /CDs composites are studied and analyzed using the transient photo‐induced voltage (TPV) technology. Combining the TPV results and kinetics analysis, it is shown that the electron transport on the In 2 O 3 interface is obviously weakened after the addition of CDs, resulting in a high H 2 O 2 selectivity. It is also demonstrated that CDs can effectively enhance the selectivity of H 2 O 2 , and the H 2 O 2 selectivity of In 2 O 3 /CDs–10 is in close proximity to 100%, which is much higher than that of pure In 2 O 3 (72%). This work will provide a new understanding and insight into addressing the challenge of low H 2 O 2 selectivity for 2e − ORR catalysts.