Sunlight-driven simultaneous CO₂ reduction and water oxidation using indium-organic framework heterostructures

Overall artificial photosynthesis, as a promising approach for sunlight-driven CO₂ recycling, requires photocatalysts with efficient light adsorption and separate active sites for coupling with H₂O oxidation. Here we show a In-based metal-organic framework (MOF) heterostructure, i.e., In-porphyrin (In-TCPP) nanosheets enveloping an In-NH₂-MIL-68 (M68N) core, via a facile one-pot synthesis that utilises competitive nucleation and growth of two organic linkers with In nodes. The coherent interfaces of the core@shell MOFs assure the structural stability of heterostructure, which will function as heterojunctions to facilitate the efficient transfer of photogenerated charge for overall photosynthesis. The In-TCPP shell in MOFs heterostructure improves CO₂ adsorption capabilities and visible light absorption to enhance the photocatalytic CO₂ reduction. Simultaneously, In-O sites in M68N core efficiently catalyze H₂O oxidation, achieving high yields of HCOOH (397.5 μmol g^-1 h^-1) and H₂O₂ (321.2 μmol g^-1 h^-1) under focused sunlight irradiation. The superior performance of this heterostructure in overall photosynthesis, coupled with its straightforward synthesis, shows great potential for mitigating carbon emissions and producing valuable chemicals using solar energy.