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

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^-.