Au/Cu-Co催化剂上甘油选择性氧化制二羟基丙酮的研究

Selective oxidation of glycerol to dihydroxyacetone over Au/Cu-Co catalysts

二羟基丙酮(DHA)是甘油选择性氧化的高附加值产物,在农业、医药等领域具有重要的应用价值。本文以溶胶-凝胶法和硬模板法制备的CuO和Cu-Co金属氧化物复合材料为载体并负载金制备了催化剂,研究了其在非碱性条件下催化甘油氧化为二羟基丙酮的性能。活性评价结果表明,Au/Cu_(0.75)Co_(0.25)催化剂具有最高的催化活性,表现出了良好的选择性,在最佳的反应条件下,甘油转化率为69.0%,DHA选择性为99.7%,催化剂较高的活性可能是由于Co的加入增强了Au与载体之间的相互作用,使得电子云密度更容易向Au发生偏移从而形成更多的Au^(0)物种并且提高了Au的颗粒分散度,Au^(0)的增加有利于形成更多的晶格氧物种O_(latt),从而增强了甘油的活化和转化,更小的Au粒径也有利于催化剂上甘油的吸附和活化,从而促进了DHA的生成。

Dihydroxyacetone(DHA)is a value-added product of selective oxidation of glycerol which plays a very important role in agriculture,pharmacy and other fields.In this paper,CuO and Cu-Co metal oxide composites prepared by sol-gel and hard template method were used as support for Au catalysts.The catalytic performance for oxidation of glycerol to dihydroxyacetone under base-free condition was studied.The activity evaluation results indicated that the Au/Cu_(0.75)Co_(0.25) catalyst had the highest catalytic activity and exhibited good selectivity,with glycerol conversion of 69.0%and DHA selectivity of 99.7%.The higher activity of the catalyst may be attributed to the fact that the addition of Co enhanced the interaction between Au and the support,which made the electron density more easily shifted toward Au to form more Au^(0) species and improved the particle dispersion of Au.The increase of Au^(0) favored the formation of more lattice oxygen species O_(latt),which enhanced the activation and conversion of glycerol,and the smaller particle size of Au also contributed the adsorption and activation of glycerol on the catalyst,thus promoting DHA yield.