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

The conversion of CO 2 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 CO 2 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 m 2 ·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 CO 2 . Lower mass transfer resistance and Warburg resistance are investigated through EIS, which significantly improves the catalytic activity for CO 2 reduction reaction (CO 2 RR). 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.