Electrochemical CO₂-to-Formate Conversion over Positive Charge Depleted Tin Sites

Upgrading CO₂to formate systems is a promising avenue for fuel production, and SnO_xis a unique low-cost candidate for this conversion. However, the high oxygen affinity of Sn sites leads to a strong adsorption of O-bound intermediates, resulting in a low efficiency of CO₂reduction. Herein, density functional theory (DFT) calculations confirmed that a H-doping strategy of SnO₂produces partially depleted positive charge Sn sites, weakening the adsorption of HCOO∗ and boosting the electron transfer kinetics. Experimentally, H-doped commercial SnO₂nanoparticles (H-SnO₂) indeed had enhanced intrinsic activity for CO₂-to-formate conversion with suppressed hydrogen evolution performance. Remarkably, H-SnO₂achieves over 90.0% formate selectivity within -0.6 to -1.0 V (vs RHE) at the industrial current density of 220 mA cm^-2.