In-situ embedded ultrafine Bi12O17Br2 nanotubes in MOF-derived hierarchical porous carbon for enhanced photocatalytic CO2 conversion to CO

Increasing the utilization efficiency of photogenerated electrons is highly recognized as one of the efficient approaches to boost the photocatalytic CO2 conversion efficiency. Herein, ZIF-67-derived porous carbon (PC) material was employed for the construction of PC@ultrafine Bi12O17Br2 nanotubes (PC@BOB NTs) composites through a facile solvothermal synthesis in order to optimize the use of excited electrons in the BOB NTs. Photoelectrochemical characterization results revealed that the introduction of PC material achieved a faster charge separation rate in the PC@BOB composites, ensuring more photogenerated electrons participate in the CO2 adsorption and activation process. Moreover, the pore structures of ZIF-67-derived PC material provided abundant confined spaces for the enrichment of CO2 molecules. After 5 h of Xenon lamp irradiation, PC@BOB composites exhibited obviously increased photocatalytic CO2 reduction activity in the pure water. When the addition amount of PC was 5 wt%, the PC@BOB-2 composite showed the highest CO evolution rate of 359.70 µmol/g, which was 2.95 times higher than that of the pure BOB NTs. This work provides some independent insights into the applications of Metal-Organic Framework (MOF)-derived hierarchical porous structures to strengthen the CO2 enrichment, as well as the excited charge utilization efficiency, thus achieving a high solar-to-fuel conversion efficiency.