Achieving Efficient CO₂ Electrochemical Reduction on Tunable In(OH)₃-Coupled Cu₂O-Derived Hybrid Catalysts

Tunable In(OH)₃-coupled Cu₂O-derived hybrid catalysts are facilely synthesized to boost the selectivity and efficiency of the electrochemical CO₂ reduction reaction (CO₂RR). The maximum faradaic efficiency (FE) of 90.37% for CO production is achieved at -0.8 V versus reversible hydrogen electrode. The mechanistic discussion suggests that the composition-dependent synergistic effect results in the enhanced selectivity for CO on the hybrid catalyst. By increasing the concentration of the electrolyte, a dramatically enhanced current density of 40.17 mA cm^-2 was achieved at -1.0 V in 0.7 M KHCO₃. Furthermore, a KHCO₃ electrolyte with high concentration promotes the selectivity of CO₂RR over the low overpotential range. At a low overpotential of 290 mV, the increased FE for CO of 74.05% is obtained in 0.7 M KHCO₃ as compared to that of 57.04% in 0.1 M KHCO₃. Combining with the synergistic effect of the catalyst and the concentration effect of the electrolyte, the hybrid catalyst achieves high efficiency, high selectivity, and high stability for CO₂RR.