A new insight for photocatalytic hydrogen production by a Cu/Ni based cyanide bridged polymer as a co-catalyst on titania support in glycerol water mixture

Abstract

A two dimensional Cu/Ni based coordination polymer [{CuII(4,4ʹ-dipy)2}{Ni(CN)4}]n·0.7(C2H6O2)·1.6(H2O) (CP-1) (4,4ʹ-dipy = 1,3-di (4-pyridyl)propane) has been demonstrated as a potential co-catalyst on TiO2 support for hydrogen evolution under UV light. CP-1/TiO2 composite exhibits considerable hydrogen production in comparison with the pristine CP-1 and TiO2 (P25), highlighting that the photocatalytic performance is significantly related with the good separation of photo generated e−/h+ pairs. Different wt. % (2.5, 5 and 7.5%) of CP-1 in CP-1/TiO2 composites were tested for photocatalytic hydrogen production in 5 vol % glycerol/water mixture. The 5 wt % CP-1/TiO2 composite displayed the greatest hydrogen production of 9.2 mmolh−1g−1. The concealed mechanism is divulged on the behalf of results obtained by cyclic voltammetry, photoluminescence and diffused reflectance/UV-visible studies which demonstrate that upon irradiation of UV light, electrons transfer from TiO2 conduction band to CP-1. CP-1 not only grabs the conduction band electrons of titania but also performes as a co-catalyst to reduce the protons into hydrogen. These results are anticipated to direct the forthcoming advancement in creating proficient, cheap semiconductor photocatalysts for solar hydrogen production.