ChemCatChem 2018-03-07

Modification of salt‐templated carbon surface chemistry for efficient oxidation of glucose with supported gold catalysts

Sandy Lama; Johannes Schmidt; Ankita Malik; Ralf Walczak; Daniel Varon Silva; Antje Völkel; Martin Oschatz

Index: 10.1002/cctc.201800104

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Abstract

Gold nanoparticles dispersed on high surface area carbon materials are investigated as heterogeneous catalysts for the selective oxidation of D‐glucose to D‐gluconic acid in aqueous solution with molecular oxygen. Salt‐templated porous carbon supports are obtained from different precursors with and without nitrogen and treated under air or hydrogen atmosphere in order to functionalize the surface with nitrogen, oxygen, or hydrogen. The influence of the surface atomic structure of carbonaceous support materials with comparable pore structure on the size and catalytic properties of the metallic nanoparticles is studied at loadings of 0.4‐0.7 wt%. These groups significantly influence the surface polarity of the support materials as well as the strength of interaction with the gold particles. This similarly influences the structure and properties of the catalysts because both the gold deposition and the glucose oxidation reaction take place in aqueous phase. Large gold particles are obtained for the rather hydrophilic supports doped with oxygen and nitrogen leading to lower catalytic activity. In contrast, the rather hydrophobic as‐made and hydrogen‐treated supports provide higher catalytic activity (metal time yield up to 1.5 molGlucose·molAu‐1·s‐1) resulting from their smaller gold particles of 3‐5 nm in diameter.