title: Designer titania-supported Au-Pd nanoparticles for efficient photocatalytic hydrogen production.
abstract: Photocatalytic hydrogen evolution may provide one of the solutions to the shift to a sustainable energy society, but the quantum efficiency of the process still needs to be improved. Precise control of the composition and structure of the metal nanoparticle cocatalysts is essential, and we show that fine-tuning the Au-Pd nanoparticle structure modifies the electronic properties of the cocatalyst significantly. Specifically, Pd(shell)-Au(core) nanoparticles immobilized on TiO2 exhibit extremely high quantum efficiencies for H2 production using a wide range of alcohols, implying that chemical byproducts from the biorefinery industry can be used as feedstocks. In addition, the excellent recyclability of our photocatalyst material indicates a high potential in industrial applications. We demonstrate that this particular elemental segregation provides optimal positioning of the unoccupied d-orbital states, which results in an enhanced utilization of the photoexcited electrons in redox reactions. We consider that the enhanced activity observed on TiO2 is generic in nature and can be transferred to other narrow band gap semiconductor supports for visible light photocatalysis.
authors.affiliation: Interdisciplinary Nanoscience Center (iNANO) and Department of Physics and Astronomy, Aarhus University , Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark.
authors.forename: Ren
authors.initials: R
authors.lastname: Su
authors.forename: Ramchandra
authors.initials: R
authors.lastname: Tiruvalam
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Logsdail
authors.forename: Qian
authors.initials: Q
authors.lastname: He
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Downing
authors.forename: Mikkel T
authors.initials: MT
authors.lastname: Jensen
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Dimitratos
authors.forename: Lokesh
authors.initials: L
authors.lastname: Kesavan
authors.forename: Peter P
authors.initials: PP
authors.lastname: Wells
authors.forename: Ralf
authors.initials: R
authors.lastname: Bechstein
authors.forename: Henrik H
authors.initials: HH
authors.lastname: Jensen
authors.forename: Stefan
authors.initials: S
authors.lastname: Wendt
authors.forename: C Richard A
authors.initials: CR
authors.lastname: Catlow
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Kiely
authors.forename: Graham J
authors.initials: GJ
authors.lastname: Hutchings
authors.forename: Flemming
authors.initials: F
authors.lastname: Besenbacher