Single atom Cu(I) promoted mesoporous titanias for photocatalytic Methyl Orange depollution and H2 production

Tailoring the physicochemical properties and hence reactivity of semiconductor photocatalysts in a predictable fashion, remains a challenge to their industrial application. Here we demonstrate the striking promotional effect of incorporating single Cu(I) atoms, on aqueous phase photocatalytic dye degradation and H ₂ production over surfactant-templated mesoporous TiO ₂. X-ray absorption spectroscopy reveals that ultra-low concentrations of copper (0.02–0.1 wt%) introduced into the mesoporous TiO ₂ surface create isolated Cu (I) species which suppress charge recombination, and confer a six-fold photocatalytic promotion of Methyl Orange degradation and four-fold enhancement of H ₂ evolution. The impact of mesopore structure and photophysical properties on photocatalytic activity is also quantified for the first time: calcination increases mesopore size and nanocrystalline order, and induces an anatase to rutile phase transition that is accompanied by a decrease in the optical band gap, increased charge carrier lifetime, and a concomitant significant activity enhancement.