In Situ Self-Assembled ZIF-67/MIL-125-Derived Co 3 O 4 /TiO 2 p-n Heterojunctions for Enhanced Photocatalytic CO 2 Reduction.

Photocatalytic CO 2 reduction to carbon fuels is regarded as an ideal and sustainable way to provide clean energy and solve environmental crisis. Herein, a p-n Co 3 O 4 /TiO 2 heterojunction photocatalyst was synthesized by one-step pyrolysis of self-assembly ZIF-67/MIL-125, which was used in photocatalytic CO 2 reduction for the first time. Co 3 O 4 nanocages were highly dispersed on the surface of TiO 2 nanoplates with an intimate contact. The optimal Co 3 O 4 /TiO 2 exhibited a significantly enhanced CO evolution rate of 1256 μmol g -1 h -1 under simulated solar light, which was 2.4 times higher than that of pure Co 3 O 4 . The high photocatalytic performance of Co 3 O 4 /TiO 2 was attributed to its enriched active sites and formed p-n heterojunctions. According to the electrocatalytic measurements, the possible mechanism and photoinduced charge transfer process were discussed in detail. We believe that this research provides a facile and efficient approach to fabricate MOF-derived heterojunction photocatalysts for CO 2 reduction.