Ni deposition on TiO2 from organometallic ligand for photocatalytic hydrogen production

Solvent-free impregnation of Ni on TiO2 produces highly dispersed nanoparticles for enhanced photocatalytic hydrogen production. The impregnation using nickel (II) acetylacetonate (Ni(acac)2) was conducted under vacuum with different Ni(acac)2 sublimation temperatures, achieving optimum Ni/TiO2 interfacial interaction for fast electron and hole pair separation. In-situ DRIFTS analysis revealed the mechanism of Ni deposition via ring opening of acetylacetonate ligands to form isolated metal nuclei. Density functional theory (DFT) calculation suggests Ni and TiO2 formed heterojunctions for efficient electron transfer, while surface oxygen vacancies are responsible for reducing the band gap energy. Hydrogen production from Ni/TiO2 exceeds the photocatalysts obtained using other synthesis methods such as photodeposition, wetness impregnation and incipient wetness impregnation, generating 1915 mu mol/gcat H2.