Versatile MOF-based nanofibrous heterostructures for engineering the CO2 photoreduction activity and selectivity: From CO to C2H5OH

Photocatalytic CO 2 reduction is a potential promising strategy for eliminating the global energy crisis and environmental issue. However, the complex reduction pathway leads to multiple possible products with limited efficiency, representing a great barrier for the further development. Herein, we report a Metal-organic framework (MOF) based heterostructure model for the efficient photoreduction of CO 2 with full controllable product selectivity between CO and C 2 H 5 OH. Novel core-sheath like MOF@TiO 2 heterostructures could be efficiently prepared by the layer-by-layer (LBL) growth of HKUST-1 onto Cu-embedded TiO 2 nanofibers (NFs), affording covalent heterointerfaces for efficient S-scheme charge separation and promising potential in photocatalytic activity regulation. By improving the CO 2 capture and retention via in situ amino-functionalization of HKUST-1, the photocatalytic CO production rate could be greatly promoted from 8.76 ± 0.84 to 43.46 ± 0.86 μmol g −1 h −1 accompanied by an enhancement of selectivity from 91.7 % to 98.3 %. Moreover, the product could be efficiently engineered into ethanol with a C 2 product selectivity of 94.2 % by introducing Cu nanoparticles (NPs) as the additional C C coupling site. The in situ FT-IR and DFT calculations reveal the mechanistic process and decisive role of amino-functionalization and Cu NPs deposition in photocatalytic activity engineering. This work highlights the key factors and significance of fabricating MOFs based heterostructures with tunable photocatalytic activity for achieving CO 2 neutralization.