화학공학소재연구정보센터
Applied Catalysis A: General, Vol.475, 161-168, 2014
Selective liquid-phase oxidation of glycerol over Au-Pd/C bimetallic catalysts prepared by electroless deposition
Liquid phase oxidation of glycerol under basic conditions was examined for a series of Au-Pd/C bimetallic catalysts prepared by electroless deposition. Enhanced activity was observed for bimetallic compositions with H-AU > 0.30, with a maximum in activity at H-AU = 0.50 having a turnover frequency similar to 20 times larger than for Pd and similar to 4 times larger than for gold. A volcano shaped curve suggests the formation of bimetallic sites composed of Au-Pd in close contact, with the maximum at H-AU = 0.50 indicating the largest concentration of bimetallic sites at that coverage. Further increase in the coverage of Au on Pd lead to a catalytic surface approaching that of monometallic Au with lower TOF values. Selectivity to glyceric acid was 80% (+/- 2%) for Pd and Au-Pd bimetallic catalysts below H-AU < 0.90. Selectivity to glycerate remained constant as long as there are sufficient Pd sites to rapidly decompose the non-selective H2O2 oxidant that is presumably produced on the Au sites. At the highest Au coverages, selectivity dropped to < 60% due to further oxidation of glycerate to C-1 and C-2 oxygenated products. (C) 2014 Elsevier B.V. All rights reserved.