Self-adaptive Reconstructed Sn-Zn Metal/Oxide-Hydroxide Hybrid for Selective Electrochemical CO2 Reduction to Formate

The composition of a catalyst significantly influences its reconstruction, which is critical for electrochemical CO 2 reduction reaction (e-CO 2 RR). However, the mechanisms of how elemental composition affect the reconstructed structure and enhance e-CO 2 RR performance require further exploration. In this study, we modulate the Sn/Zn ratios in Sn-Zn alloy precursors to promote CO 2 -to-formate (HCOO⁻) conversion through a self-adaptive reconstructed structure with potential changing. Notably, the electrocatalyst exhibits exceptional CO 2 -to-HCOO⁻ performance at a Sn/Zn mass ratio of 1:1 (SnZn-55), achieving a Faraday efficiency (FE) >82% across a wide potential range (-0.73 to -1.13   V), a high HCOO⁻ partial current density of 45.75   mA   cm⁻² at potential of highest HCOO- FE (92% at -0.93   V) and stability for up to 2000 hours. Systematic studies reveal that the reconstructed Sn-Zn metal/oxide-hydr oxide hybrid in SnZn-55 adapts dynamically to varying potentials, enhancing CO 2 -to-HCOO⁻ conversion by promoting proton accumulation, suppressing hydrogen evolution, and facilitating CO 2 -to-HCOO - basic steps. These findings provide deep insights into the interplay between elemental composition, reconstructed structure, and e-CO 2 RR performance, offering valuable guidance for designing advanced electrocatalysts for efficient CO 2 reduction in broad potential range.