Titania supported MOF-199 derived Cu–Cu2O nanoparticles: highly efficient non-noble metal photocatalysts for hydrogen production from alcohol–water mixtures

Abstract

Fabrication of cheap and efficient photocatalysts is pivotal for practical applications of solar energy devices. Here, we illustrate a novel trend in generating Cu–Cu₂O nanoparticles over TiO₂ for water splitting systems. Titanium(IV) isopropoxide was hydrolysed in the presence of various wt% of MOF-199 ([Cu₃(BTC)₂(H₂O)₃]_n) to obtain TiO₂–MOF-199 composite materials. These composite materials are then calcined at various temperatures in air to produce highly dispersed Cu–Cu₂O nanoparticles over TiO₂; these nanoparticles were tested as photocatalyts for hydrogen generation from alcohol–water mixtures. The photocatalyst 1 wt% Cu/TiO₂-400 was found to exhibit a hydrogen production rate some 2.5 times higher than that of CuO prepared by conventional precipitation methods. The calcination temperature of the TiO₂–MOF composite was found to affect the oxidation state of Cu and the photocatalytic activity, with an optimum performance achieved at 400 °C. Calcination beyond this temperature led to oxidation and agglomeration of Cu–Cu₂O nanoparticles into larger CuO deposits, which reduce the H₂ production activity (ca. 80%).