Matched Redox Kinetics on Triazine-Based Carbon Nitride/Ni(OH)2 for Stoichiometric Overall Photocatalytic CO2 Conversion

Mismatched reaction kinetics of CO2 reduction and H2O oxidation is the main obstacle limiting the overall photocatalytic CO2 conversion. Here, a molten salt strategy is used to construct tubular triazine-based carbon nitride (TCN) with more adsorption sites and stronger activation capability. Ni(OH)(2) nanosheets are then grown over the TCN to trigger a proton-coupled electron transfer for a stoichiometric overall photocatalytic CO2 conversion via "3CO(2) + 2H(2)O = CH4 + 2CO + 3O(2)." TCN reduces the energy barrier of H2O dissociation to promote H2O oxidation to O-2 and supply sufficient protons to Ni(OH)(2), whereby the CO2 conversion is accelerated due to the enhanced proton-coupled electron transfer process enabled by the sufficient proton supply from TCN. This work highlights the importance of matching the reaction kinetics of CO2 reduction and H2O oxidation by proton-coupled electron transfer on stoichiometric overall photocatalytic CO2 conversion.