Theoretical Screening and experimental validation of M3(2,3,6,7,10,11-hexahydroxytriphenylene)2 for electrocatalytic CO2 reduction

Abstract

Metal-organic frameworks (MOFs) has shown promising applications in electrocatalytic CO2 reductions due to their high specific surface area, abundant active sites and clear structure, but the conductivity of MOFs is a great challenge. Herein, a two-dimensional (2D) coordination network materials M3(2,3,6,7,10,11-hexahydroxytriphenylene)2 (M3(HHTP)2) with a good conductivity were systematically investigated and theoretical screened as promising electrocatalysts for the electrocatalytic carbon dioxide reduction reactions (CO2RR) combining density function theory (DFT) calculations and experimental validation. The theoretical calculations show that CH4 is the main reduction product for CO2RR catalyzed by Cu3(HHTP)2 and Ti3(HHTP)2. However, favorable product by Sc3(HHTP)2, Co3(HHTP)2, Ni3(HHTP)2 and Zn3(HHTP)2 is CO. For V3(HHTP)2 and Mn3(HHTP)2, HCHO is dominant product, but the reaction of V3(HHTP)2 catalyst required a high overpotential above 1.69 V. HCOOH is primarily produced from Cr3(HHTP)2 and Fe3(HHTP)2. Furthermore, the electrochemical CO2RR catalyzed by Cu3(HHTP)2 and Ni3(HHTP)2 were completed to validate theoretical screening. It is found that Cu3(HHTP)2 hold excellent CO2RR activity with 42.88% Faraday efficiency (FE) of CH4 with 107.92 mA cm−2 at -1.30 V vs RHE, and Ni3(HHTP)2 has 68.27% CO FE with a current density of 59.92 mA cm−2 at -0.50 V vs RHE. This work showed that theoretical screening work can provide a highly effective approach to investigate the reaction mechanism and can aid in designing novel catalysts for CO2RR, and would greatly promote design of MOF catalysts for CO2RR.