Modulating Electronic Structure of Amorphous Indium Oxide for Efficient Formate Synthesis Towards CO2 Electroreduction

Abstract

Tuning the electronic structure of catalysts is an efficient approach to optimize the catalytic performance of CO₂ electroreduction. Herein, we constructed an efficient catalyst consisting of amorphous InO_X with a cotton-like structure spreading over N doped carbon (N-C) substrate to extend the catalysts-substrate interfaces for enhancing electron-transfer effect. The amorphous InO_X growing on N-C substrate (InO_X/N-C) exhibited an improved current density of -34.4 mA cm^-2. Notably, a faradaic efficiency for formate (HCOO^-) over the amorphous InO_X/N-C reached 79.6 % at -1.0 V versus reversible hydrogen electrode, 1.8 times as high as that (44.2 %) over the amorphous InO_X growing on carbon black substrate. Mechanistic studies revealed that the introduction of N-C as substrates accelerated charge-transfer process on the catalytic surface of InO_X/N-C. Density functional theory calculations further revealed that the interactions between N-C substrate and InO_X not only facilitated the potential-determining *HCOO protonation, but also inhibited hydrogen evolution, thus improving the catalytic performance for the production of HCOO^-.

Keywords: Amorphous InOX; CO2 electroreduction; Electronic structure; Formate synthesis; Supported Catalysts.