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)(2)PDC2] was synthesized, and it transformed into Ag doped Co3O4 catalyst, which exhibits excellent electro-catalytic performance for reduction of CO2 in water to syngas (H-2 + 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 H-2. The stability of the samples can be maintained for more than 10 h at -1.8 V vs. SCE. The ratio of production between H-2 and CO can be controlled by varying the potential values.