Electrochemical CO2 Reduction On Two-Dimensional Metal 1,3,5-triamino-2,4,6- Benzenetriol Frameworks: A Density Functional Study

Electrocatalytic CO2 reduction reaction (CO2RR) is a very prospective strategy to reduce CO2 to valuable fuels and chemical products, thereby alleviating the growing energy crisis and greenhouse effect. In this study, CO2RR mechanisms on M3(TABTO)2 (M=Sc-Cu, Y-Mo and Ru-Rh, TABTO=1,3,5-triamino-2,4,6-benzenetriol) are investigated by means of density functional method. The results show that the studied catalysts are stable thermodynamically. Co3(TABTO)2 exhibits the best catalytic performance for the formation of CH3OH with the same overpotential of 0.41 V both in the gas phase and in solution. For Fe3(TABTO)2, however, the product is HCOOH with the overpotential of 0.29 V in the gas phase and 0.70 V in solution. For Ru3(TABTO)2 to produce CH4, solvent effect reduces the overpotential significantly from 0.97 V in the gas phase to 0.54 V in solution, making it to be a promising CO2RR catalyst. Moreover, the improvement of CO2RR catalyst activity can be achieved by the axial oxygen modification in M3(TABTO)2 (M=Sc, Y and V). A good relationship between d band center and overpotential is observed, which might provide us with a new direction to design the promising catalyst.