Preparation and performance of platinum catalysts for hydrosilylation supported by polyphenols modified SBA-15

Abstract

Surface modification of porous particles with functional groups is a common way to anchor noble metal catalysts. Herein, surface modification of mesoporous silica (SBA-15) was performed using polyphenols (PNs) through oxidative copolymerization of tea polyphenols and theophylline. The PNs modification ratios on subsequent both Pt loading and chemical states of supported Pt are thoroughly investigated. Catalytic activity of the resulting catalysts was evaluated through various hydrosilylation reactions, while its recyclability was also examined. Results show that modification with PNs can not only facilitates the loading of Pt, but also favors the formation of more active Pt⁰ species, thereby increase the catalytic activity of the catalyst. Among them, the SBA-15-PNs-Pt-2 catalyst with the highest PNs ratios exhibits both high activity, good selectivity of anti-Markovnikov addition products and excellent recycling performance. Meanwhile, whether it is under low catalyst loadings or toward the hydrosilylation reactions between a series of substrates, the SBA-15-PNs-Pt-2 catalyst all exhibit undeclined activity, which again signifies the substantial role of PNs in both loading and anchoring Pt species.