Molecular trapdoor mechanism of In-SSZ-13(MP) holds promise for selective electrochemical reduction of CO2 at low concentrations

The unique molecular trapdoor mechanism of chabazite zeolites provides an ideal platform for CO2 integrative adsorption and conversion. Herein, a mesoporous In-SSZ-13(MP) catalyst was successfully synthesized through desiliconization combined with anchoring uniformly dispersed indium (In) active sites, which achieved the highest formate Faraday efficiency (FEHCOO-) of 92.0 % and a formate partial current density (jHCOO-) of 133.3 mA cm−2 for electrochemical CO2 reduction reaction (CO2RR) at a moderate overpotential of 0.8 V. Experimental results combined with DFT calculations reveal the reaction mechanism of In-SSZ-13(MP) electrocatalytic reduction of CO2: as the only channel into the In-SSZ-13(MP) crystal, the gatekeeper (cation, In3+) in eight-membered ring (8MR) deviates from its original position induced by CO2 molecule, then CO2 poured into CHA cage and fully reacted with uniformly distributed indium active sites.