Novel photo-functional material based on homo-metallic cyanide bridged nickel coordination polymer and titania for hydrogen generation

Abstract

© 2018 Elsevier B.V. A new three dimensional (3D) cyanide-bridged homo-metallic coordination polymer [{NiII(4,4′-dipy)4}{Ni(CN)4}]n·(4,4′-dipy)·3H2O·C2H6O2 (1) (4,4′-dipy = 1,3-di(4-pyridyl)propane) has been functionalized by making its composite with P25 (titanium dioxide) for photocatalytic hydrogen production from water. 1/TiO2 composite manifests appreciable hydrogen production in contrast with the virgin compounds 1 and P25, accentuating that the photocatalytic activity greatly corresponds to the well separation of photo generated charge carriers. Different wt% (2.5%, 5%, 7% and 10%) of 1 in 1/TiO2 composites were assessed for photocatalytic activity in 5 vol% glycerol water mixture. The 5 wt% 1/TiO2 composite showed the maximum hydrogen production of 11.2 mmol h−1 g−1. The veiled mechanism is revealed on the basis of results obtained by cyclic voltammetry, photoluminescence and diffused reflectance UV–visible studies. The key step in proposed mechanism is the transfer of electrons from conduction band of TiO2 to compound 1. Compound 1 not only quenches the conduction band electrons of titania but also acts as a co-catalyst to reduce the protons into hydrogen. This outcome is envisaged to manage the future advancement of proficient, inexpensive semiconductor photocatalysts for solar Hydrogen production.