Stable nanoporous Sn/SnO2 composites for efficient electroreduction of CO2 to formate over wide potential range

Seeking for an efficient and stable electrocatalyst in a wide potential range is vital for the electrocatalytic reduction of CO2 into high-value added liquid fuels. Herein, the nanoporous Sn/SnO2 (np-Sn/SnO2) composites with high mesoporosity are fabricated through a two-step dealloying strategy. At all the applied potentials, the as-prepared np-Sn/SnO2 composites show obviously higher Faradaic efficiency of formate relative to porous Sn structures. More importantly, the np-Sn/SnO2 composites exhibit high FEHCOO− of >70% at a wide potential range from −0.8 to −1.4 V vs. RHE. In addition, np-Sn/SnO2 composites possess an excellent long-term stability over 58 h at −0.8 V vs. RHE. As compared to the porous Sn structures, the superiority of np-Sn/SnO2 composites toward electroreduction of CO2 to formate could be mainly attributed to their unique mesoporous structures with high-density grain boundaries and large surface area.