title: Direct synthesis of hydrogen peroxide and benzyl alcohol oxidation using Au-Pd catalysts prepared by sol immobilization.
abstract: We report the preparation of Au-Pd nanocrystalline catalysts supported on activated carbon prepared via a sol-immobilization technique and explore their use for the direct synthesis of hydrogen peroxide and the oxidation of benzyl alcohol. In particular, we examine the synthesis of a systematic set of Au-Pd colloidal nanoparticles having a range of Au/Pd ratios. The catalysts have been structurally characterized using a combination of UV-visible spectroscopy, transmission electron microscopy, STEM HAADF/XEDS, and X-ray photoelectron spectroscopy. The Au-Pd nanoparticles are found in the majority of cases to be homogeneous alloys, although some variation is observed in the AuPd composition at high Pd/Au ratios. The optimum performance for the synthesis of hydrogen peroxide is observed for a catalyst having a Au/Pd 1:2 molar ratio. However, the competing hydrogenation reaction of hydrogen peroxide increases with increasing Pd content, although Pd alone is less effective than when Au is also present. Investigation of the oxidation of benzyl alcohol using these materials also shows that the optimum selective oxidation to the aldehyde occurs for the Au/Pd 1:2 molar ratio catalyst. These measured activity trends are discussed in terms of the structure and composition of the supported Au-Pd nanoparticles.
authors.affiliation: School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, United Kingdom.
authors.forename: James
authors.initials: J
authors.lastname: Pritchard
authors.forename: Lokesh
authors.initials: L
authors.lastname: Kesavan
authors.forename: Marco
authors.initials: M
authors.lastname: Piccinini
authors.forename: Qian
authors.initials: Q
authors.lastname: He
authors.forename: Ramchandra
authors.initials: R
authors.lastname: Tiruvalam
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Dimitratos
authors.forename: Jose A
authors.initials: JA
authors.lastname: Lopez-Sanchez
authors.forename: Albert F
authors.initials: AF
authors.lastname: Carley
authors.forename: Jennifer K
authors.initials: JK
authors.lastname: Edwards
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Kiely
authors.forename: Graham J
authors.initials: GJ
authors.lastname: Hutchings
mesh_terms: D000497:Alloys / Q000138:chemical synthesis / Q000737:chemistry; D019905:Benzyl Alcohol / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D006046:Gold / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000138:chemical synthesis* / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry; D010084:Oxidation-Reduction; D010165:Palladium / Q000737:chemistry*; D010316:Particle Size; D013499:Surface Properties
chemical_list: D000497:Alloys; D010165:Palladium; D006046:Gold; D006861:Hydrogen Peroxide; D019905:Benzyl Alcohol