Ag-doped Co3O4 catalyst derived from heterometallic MOF for syngas production by electrocatalytic reduction of CO2 in water

Electrocatalytic reduction of CO2 to useful fuels or chemicals is a promising path for carbon recycling. In this study, a novel mixed-metallic MOF [Ag4Co2(pyz)PDC4][Ag2Co(pyz)2PDC2] was synthesized, and it transformed into Ag doped Co3O4 catalyst, which exhibits excellent electro-catalytic performance for reduction of CO2 in water to syngas (H2 + CO). The as-prepared Ag/Co3O4 material exhibits a high selectivity of CO in 0.1 M KHCO3 aqueous solution (CO2 saturated) with the corresponding faradaic efficiency up to 55.6%. Compared with the Ag/Co3O4 electrode, the maximum faradaic efficiency (FE) of CO of pure Co3O4 is 21.3% at − 1.8 V vs. SCE. The results show that the presence of Ag can improve the efficiency of CO significantly, thereby inhibiting the production of H2. The stability of the samples can be maintained for more than 10 h at − 1.8 V vs. SCE. The ratio of production between H2 and CO can be controlled by varying the potential values.