Coconut Shell Waste-Derived Porous Carbon-Supported Sn Catalysts for Efficient Electrochemical CO2Reduction to Formic Acid and Deuterated Formic Acid

Abstract

Industrial-level electrochemical CO2 reduction reaction (CO2RR) to form HCOO– and DCOO– requires robust Sn catalysts with high performance. In this study, the hydrothermal method was employed to load varying amounts of Sn precursors onto waste biomass-derived porous carbon to investigate the structure–activity relationship between Sn loading forms and HCOO– selectivity. Through comprehensive ex/in situ characterizations, we discovered that with 5% Sn precursor addition, highly dispersed SnO2 nanoparticles formed on the carbon support, enabling the catalyst to exhibit exceptional HCOO– activity (Faradaic efficiency exceeding 90%) across a broad potential window. In situ attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and in situ Raman spectroscopy revealed that the highly dispersed SnO2 nanoparticles enhance the stability of the *OCHO intermediate. Furthermore, when H2O was replaced with D2O, the generation of DCOO– was observed, and good selectivity was maintained. This study provides a facile strategy for waste biomass conversion and the design of Sn-based catalysts for DCOO– production.