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.