Temperature modulation of defects in NH₂-UiO-66(Zr) for photocatalytic CO₂ reduction

Defect engineering can be a promising approach to improve the photocatalytic performance of metal-organic frameworks (MOFs). Herein, a series of defective NH₂-UiO-66(Zr) materials were synthesized via simply controlling the synthesis temperature, with concentrated HCl as the modulator and then these as-prepared samples were used to systematically investigate the effects of their structural defects on photocatalytic CO₂ reduction. Remarkably, these MOFs with defects exhibit significantly enhanced activities in photocatalytic CO₂ reduction, compared with the material without defects. The defect engineering creates active binding sites and more open frameworks in the MOF, and thus facilitates the photo-induced charge transfer and restrains the recombination of photo-generated charges efficiently. The current work provides an instructive approach to improve the photocatalytic efficiency by taking advantage of the structural defects in MOFs, and could also inspire more work on the design of advanced defective MOFs.