Controlled cerium doping in In ₂ O ₃ derived from an In-MOF to boost electrocatalytic CO ₂ reduction for selective formate production

Utilizing electrocatalytic technology to convert CO₂ into value-added carbon products contributes to establishing a carbon-neutral cycle and alleviating environmental pressure. However, developing electrocatalysts with high activity and selectivity remains a significant challenge. In this work, we designed a feasible strategy involving the use of an In-MOF as a sacrificial template, which was pyrolytically transformed into Ce-doped In₂O₃ with varying doping ratios via controlled Ce doping. The optimized Ce_0.85-In₂O₃ catalyst demonstrated outstanding performance, achieving a high formate faradaic efficiency of 92.05% and a current density of -100.98 mA cm^-2. Experimental results revealed that the abundant oxygen vacancies in the catalyst and electron transfer between the constituents synergistically enhanced catalytic activity and formate selectivity. In situ attenuated total reflectance surface enhanced infrared absorption spectroscopy (ATR-SEIRAS) tests validated that Ce-doped In₂O₃ facilitates the formation of key formate intermediates at lower applied potential. This work provides new insights for exploring the application of metal-doped MOF derivatives in the electrocatalytic CO₂ reduction reaction.