Mesoporous silicon-carbon composites: Novel supports of platinum nanoparticles for highly efficient selective oxidation of glycerol

Abstract

Selective oxidation of glycerol is an extremely challenging reaction because of that three hydroxyl groups in glycerol are prone to randomly oxidize, resulting in unsatisfactory selectivity. In this work, silicon-carbon composites (Si-C-n) were designed and prepared as novel supports for nano Pt catalyst to boost the activity and selectivity in oxidation of glycerol to glyceric acid (GLYA). By the tannic acid/silicic acid self-assembly and carbonization process, mesoporous Si-C-n microspheres with high surface area. After the Pt loading, the as-prepared catalysts Pt/Si-C-3 exhibited significantly enhanced glycerol conversion (74.4%) and exceptional GLYA selectivity (86.7%). It also showed excellent stability, experiencing no obvious performance loss after six cycles. Characterizations and theoretical calculations verify that the introduction of Si species in the carbon framework provides preferred weak acid sites in Pt/Si-C-n, which could promote the desorption of product GLYA, enhance the electronic interaction between Pt and the support, and reduce the activation energy of rate-determining step, thus contributing to a high activity and selectivity to GLYA.