Enhanced UV–vis photoinduced hydrogen evolution of metalloporphyrin sensitized PSf/TiO2 MMMs by varying center metal ion complexed in porphyrin

In order to produce hydrogen fuel in green and environmentally friendly method, a series of novel metal-5,10,15,20- meso -tetra(p-hydroxypheny) porphyrin (MTHPP, M = Cu, Zn and Ni) mono-dispersedly functionalized MTHPP-sg-PSf/TiO 2 mixed matrix membranes (MP 12 -M 3 MMMs) were prepared via the in-situ surface grafting. UV–Vis induced hydrogen evolution from water shows an increasing order of NiP 12 -M 3  < P 12 -M 3  < ZnP 12 -M 3  < CuP 12 -M 3 , and the hydrogen production by CuP 12 -M 3 was up to 70.63 mmol/m 2 , which is 7.25 times higher than that of control membrane without metal ion (P 12 -M 3 ). The apparent quantum yield (AQY) at λ = 420 nm of CuP 12 -M 3 was 31.7 %, which are better than most reported photocatalysts. Furthermore, the hydrogen evolution performance of the MP 12 -M 3 MMMs are higher than that of equivalent MTHPP-TiO 2 powder, indicating that the porous membrane can immobilize porphyrin and TiO 2 monodispersely to improve its catalytic performance significantly. Finally, the photocatalytic mechanism of the MP 12 -M 3 MMMs was explored by electrons transfer rate constant (k ET ), excited state oxidation potential (E OX(dye*) ), electron spin resonance (ESR) and density functional theory (DFT). This work details the construction a photocatalytic membrane by novel surface modification method, which can be used for long-term photolysis of water to produce hydrogen and provide an effective strategy for improving hydrogen production performance.