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.