Chlorosome-Like Molecular Aggregation of Chlorophyll Derivative on Ti3C2Tx MXene Nanosheets for Efficient Noble Metal-Free Photocatalytic Hydrogen Evolution

Efficient photocatalytic hydrogen evolution reaction (HER) in the visible-to-near infrared region at a low cost remains a challenging issue. This work demonstrates the fabrication of organic-inorganic composites by deposition of supramolecular aggregates of a chlorophyll derivative, namely, zinc methyl 3-devinyl-3-hydroxymethyl-pyropheophorbide a (Chl) on the surface of Ti3C2Tx MXene with 2D accordion-like morphology. This composite material is employed as noble metal-free catalyst in photocatalytic HER under the white light illumination, where Chl serves as a small molecule organic semiconductor component instead of ordinary inorganic and polymer organic semiconductors such as TiO2 and g-C3N4, and Ti3C2Tx serves as a co-catalyst. Different composition ratios of Chl/Ti3C2Tx are compared for their light-harvesting ability, morphology, charge transfer efficiency, and photocatalytic performance. The best HER performance is found to be as high as 52 +/- 5 mu mol h(-1) g(cat)(-1) after optimization. Such a large HER activity is attributed to the efficient light harvesting followed by exciton transfer in Chl aggregates and the resultant charge separation at the interface of Chl/Ti3C2Tx.