Catalytic hydrogenation performance of ZIF-8 carbide for electrochemical reduction of carbon dioxide

Abstract

The conversion of CO2 electrocatalytic hydrogenation into energy-rich fuel is considered to be the most effective way to carbon recycle. Nitrogen-doping carbonized ZIF-8 is proposed as carrier of the earth-rich Sn catalyst to overcome the limit of electron transfer and CO2 adsorption capacity of Sn. Hierarchically porous structure of Sn doped carbonized ZIF-8 is controlled by hydrothermal and carbonization conditions, which induces much higher specific surface area than that of the commercial Sn nanoparticle (1003.174 vs. 7.410 m2·g−1). The shift of nitrogen peaks in X-ray Photoelectron Spectroscopy spectra indicates interaction between ZIF-8 and Sn, which induces the shift of electron cloud from Sn to the chemical nitrogen to enhance conductivity and regulate electron transfer from catalyst to CO2. Lower mass transfer resistance and Warburg resistance are investigated through EIS, which significantly improves the catalytic activity for CO2 reduction reaction (CO2RR). Onset potential of the reaction is reduced from −0.74 V to less than −0.54 V vs. RHE. The total Faraday efficiency of HCOOH and CO reaches 68.9% at −1.14 V vs. RHE, which is much higher than that of the commercial Sn (45.0%) and some other Sn-based catalyst reported in the literature.