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

Abstract

Photocatalytic CO2 reduction to carbon fuels is regarded as an ideal and sustainable way to provide clean energy and solve environmental crisis. Herein, a p-n Co3O4/TiO2 heterojunction photocatalyst was synthesized by one-step pyrolysis of self-assembly ZIF-67/MIL-125, which was used in photocatalytic CO2 reduction for the first time. Co3O4 nanocages were highly dispersed on the surface of TiO2 nanoplates with an intimate contact. The optimal Co3O4/TiO2 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 Co3O4. The high photocatalytic performance of Co3O4/TiO2 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 CO2 reduction.