Incorporation of a Binuclear Cobalt Complex into MOFs for Photocatalytic CO<sub>2</sub> Reduction with H<sub>2</sub>O as an Electron Donor
Huifeng Wang, Hong Yuan, Si-Zhan Feng, Bao‐Xia Dong, Di‐Chang Zhong
Abstract
The development of molecular composite photocatalysts for cost-effective, sacrificial-reagent-free CO 2 reduction is desirable but challenging. Herein, we employed an in situ encapsulation strategy to encapsulate the binuclear cobalt complex (Co 2 L) within NH 2 -MIL-125 and synthesized a range of MOF-based composites with varying cobalt content for photocatalytic CO 2 reduction. The photocatalytic results showed that the catalytic performance increased with the increase in Co 2 L content, reaching a rapid CO generation rate of 27.95 μmol·g –1 ·h –1, over 5 times that of bare NH 2 -MIL-125, with water as the electron donor instead of any organic sacrificial agent. This composite catalyst effectively harnesses the advantages of both molecular catalysts and MOFs, leveraging the superior catalytic activity of molecular catalysts while also capitalizing on the light absorption and water oxidation capabilities of MOFs, resulting in a remarkable ability for photocatalytic CO 2 reduction. The photocatalytic mechanism involving electron transfer and CO 2 activation has been revealed by photoluminescence spectroscopy, in situ X-ray photoelectron spectroscopy, in situ diffuse reflectance infrared Fourier transform spectroscopy, and other control experiments.