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

Mismatched reaction kinetics of CO 2 reduction and H 2 O oxidation is the main obstacle limiting the overall photocatalytic CO 2 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 CO 2 conversion via "3CO 2 + 2H 2 O = CH 4 + 2CO + 3O 2 ." TCN reduces the energy barrier of H 2 O dissociation to promote H 2 O oxidation to O 2 and supply sufficient protons to Ni(OH) 2 , whereby the CO 2 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 CO 2 reduction and H 2 O oxidation by proton-coupled electron transfer on stoichiometric overall photocatalytic CO 2 conversion.