Synthesis of MOF templated Cu/CuO@TiO2 nanocomposites for synergistic hydrogen production

Abstract

A copper metal–organic framework (Cu-MOF) provides access to Cu/CuO@TiO₂ hybrid nanocomposites with highly dispersive copper species adsorbed on a TiO₂ semiconducting system. This novel nanostructure exhibits efficient hydrogen evolution performance under solar illumination of intensity ∼1 Sun. The rate of H₂ production was systematically optimized under different operational parameters. Experimental observation reveals that mesoporous Cu/CuO@TiO₂ nanocomposite with 0.5 wt% Cu loading showed the highest rate of H₂ production (286 mmol g⁻¹ h⁻¹), which is considerably higher than that of CuO loaded TiO₂ prepared using a conventional impregnation method. This high photocatalytic H₂ production activity is attributed predominantly to the presence of surface deposited Cu⁰ species and the small size of the heterojunction (1–2 nm) between CuO and TiO₂, which facilitate interfacial charge carrier transfer from the TiO₂ nanoparticles. The catalyst showed good recyclability under prolonged exposure (30 h) to solar irradiation. Unlike many Pt decorated TiO₂ photocatalysts, this hybrid photocatalyst provides an inexpensive means of harnessing solar energy.