Electronic interactions between SnO2 crystals and porous N-doped carbon nanoflowers accelerate electrochemical reduction of CO2 to formate.

The electrochemical carbon dioxide reduction reaction (CO2RR) to formic acid or formate is a highly effective approach for achieving carbon neutrality. However, multiple proton-coupling-electronic processes and the instability of the catalysts caused by surface poisoning greatly limit the overall efficiency of CO2RR to formate. Here, a facile method was developed to anchor ∼2.60 nm SnO2 crystals onto porous N-doped carbon nanoflowers (SnO2@N-GPC) for high-efficiency formate production. The maximum Faraday efficiency (FE) of the SnO2@N-GPC reached 96.3 % at -1.2 V vs reversible hydrogen electrode (RHE) and was more than 80.0 % in the potential region from -1.0 to -1.5 V vs RHE with ten hours of operating stability. The experimental results and density functional theory (DFT) calculations demonstrated that the electronic interactions between SnO2 and N-GPC precipitated by electron transfer from SnO2 to N-GPC at the interface improved the phase stability of the SnO2@N-GPC, which improved its stability for the CO2RR. Furthermore, the electronic interactions enhanced the adsorption of CO2 on the catalyst, accelerating the rate of the formation of key intermediates, and reducing the energy barrier of the rate-limiting step for generating formate. This study provides an efficient strategy for developing highly active and stable non-precious metal catalysts for the conversion of CO2 to high-value chemicals.