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

• Published in: Applied catalysis. B, Environmental Vol. 232; pp. 501 - 511
• Main Authors: Trofimovaite, Rima, Parlett, Christopher M.A., Kumar, Santosh, Frattini, Lucia, Isaacs, Mark A., Wilson, Karen, Olivi, Luca, Coulson, Ben, Debgupta, Joyashish, Douthwaite, Richard E., Lee, Adam F.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.09.2018
• Subjects: Copper; Mesoporous; Photocatalysis; Titania; XAS; XAS; Titania; Mesoporous; Copper; Photocatalysis
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2018.03.078

[Display omitted] •A facile route to mesoporous titanias with tunable photophysical properties.•Photocatalytic dye degradation and H2 production ∝ mesopore size (∝ 1/band gap).•Ultra-low Cu promoter levels deliver four- to six-fold photoactivity enhancements.•First demonstration of atomically dispersed Cu(I) as a photocatalytic promoter. 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 H2 production over surfactant-templated mesoporous TiO2. X-ray absorption spectroscopy reveals that ultra-low concentrations of copper (0.02–0.1 wt%) introduced into the mesoporous TiO2 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 H2 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.