Electronic Interactions between Sno2 Crystals and Porous N-Doped Carbon Nanoflowers Accelerate Electrochemical Reduction of Co2 to Formate

Abstract

Electrochemical carbon dioxide reduction reaction (CO2RR) to formic acid or formate is a highly effective approach for achieving carbon neutrality. However, multiple proton-coupling-electron process and instability of catalysts caused by surface reconstruction greatly limit the overall efficiency of CO2RR to formate. Here, we developed a facile method anchoring ~2.6 nm SnO2 crystals on the porous N-doped carbon nanoflowers (SnO2@N-GPC) for high-efficiency formate production. The maximum Faraday efficiency (FE) of the SnO2@N-GPC reaches to 96.3% at -1.2 V vs reversible hydrogen electrode (RHE) and larger than 80.0% at the potential region from -1.0 to -1.5 Vvs. RHE along with 10 hours operating stability. The experimental results and density functional theory (DFT) calculations demonstrate that the electronic interactions between SnO2 and N-GPC caused by electron transfer from SnO2 to N-GPC at the interface improve the phase stability of the SnO2@N-GPC, improving its stability for CO2RR. Furthermore, the electronic interactions enhance the adsorption ability of CO2, boost the formation rate of the key intermediates, and reduce the energy barrier of the rate-limiting step for the formate formation. This study provides an efficient strategy for developing highly active and stable non-precious catalysts for the conversion of CO2 to high-value chemicals.

Keywords: Electrocatalytic CO2 reduction, Formic acid, Electronic interactions, SnO2, Nanoflower