AuCu负载型催化剂的制备及其甘油选择性催化氧化活性研究

Study on Preparation and Glycerol Selective Catalytic Oxidation Activity of Supported AuCu Nanoparticle Catalysts

生物柴油被认为是石油和柴油的完美替代品,在其生产过程中会产生大量副产物甘油,如何高效使用这些甘油是亟待解决的问题。为提高甘油利用率,本文通过硼氢化钠还原法制备了Au、不同摩尔比Au_(1)Cu_(3)、Au_(1)Cu_(1)和Au_(3)Cu_(1)纳米颗粒,并将这些纳米颗粒分别负载在不同载体(Al_(2)O_(3)、TiO_(2)、SiO_(2)和CeO_(2))上,考察其甘油选择性催化氧化制2-羟基丙酮(DHA)反应性能。结果表明,AuCu/Al_(2)O_(3)展现出了最优异的催化性能,其甘油的转化率和DHA的选择性分别为30%和60%,这主要归因于Au和Cu的协同作用以及Al_(2)O_(3)的载体效应。此外,还对催化反应溶剂和催化剂稳定性进行了探究。相比其他溶剂,反应体系为水相时,DHA的选择性最高为60%;催化剂经4次循环稳定性试验,甘油的转化率和DHA的选择性依然维持在30%和60%左右,表明催化剂有良好的催化稳定性。

Biodiesel is considered to be a perfect alternative to petroleum and diesel,and its production process produces a large amount of glycerin,a by-product,which is an urgent problem to be solved.In order to improve the utilization rate of glycerol,Au,Au_(1)Cu_(3),Au_(1)Cu_(1)and Au_(3)Cu_(1)nanoparticles with different molar ratios were prepared by sodium borohydride reduction method,and these nanoparticles were loaded on different supports(Al_(2)O_(3),TiO_(2),SiO_(2)and CeO_(2)),respectively.The selective catalytic oxidation of glycerol to 2-hydroxyacetone(DHA)was used as a probe reaction to investigate the catalytic performance of different catalysts.The results showed that AuCu/Al_(2)O_(3)exhibited the best catalytic performance,with a glycerol conversion rate and DHA selectivity of 30%and 60%,respectively,which was mainly attributed to the synergistic effect of Au and Cu and the carrier effect of Al_(2)O_(3).In addition,the reaction solvent and the stability of the catalyst were also explored.The results showed that compared with other solvents,the selectivity of DHA was up to 60%when the reaction system was aqueous.In addition,the conversion rate of glycerol and the selectivity of DHA remained at about 30%and 60%after four cycles of tests,indicating that the catalyst has good catalytic stability.