Intentional construction of high-performance SnO2 catalysts with a 3D porous structure for electrochemical reduction of CO2

Abstract

Herein, SnO₂-NC (SnO₂-nanocube) and SnO₂-NF (SnO₂-nanoflake) electro-catalysts featuring a large specific surface area and 3D porous structure were successfully constructed via acid etching and sulfurization–desulphurization methods, respectively. As catalysts for the electrochemical reduction of CO₂, the faradaic efficiency (F_HCOO⁻+CO = 82.4%, 91.5%, respectively) and partial current density (j_HCOO⁻+CO = 10.7 and 11.5 mA cm⁻², respectively) of SnO₂-NCs and SnO₂-NFs were enhanced in comparison with SnO₂-NPs (SnO₂-nanoparticles, F_HCOO⁻+CO = 63.4%, j_HCOO⁻+CO = 5.7 mA cm⁻²) at −1.0 V vs. RHE. The enhanced catalytic activity is attributed to their uniform 3D porous structure, high specific surface area and excellent wettability. Additionally, the morphology of SnO₂-NCs and SnO₂-NFs was largely preserved after electrolyzing for 12 h (after 12 h of electrolysis), indicating the effective buffering effect of the 3D structure in electrolysis. Naturally, the current density and faradaic efficiency of the SnO₂-NC and SnO₂-NF catalysts remained nearly unchanged after long-term stability measurements, revealing great stability.