A Surface-Cofunctionalized Silica Supported Palladium Catalyst for Selective Hydrogenation of Nitrile Butadiene Rubber with Enhanced Catalytic Activity and Recycling Performance

A co-functionalized silica-supported palladium catalyst has been successfully designed and controllably fabricated for the selective hydrogenation of nitrile butadiene rubber (NBR). The amino groups on the surface can anchor and stabilize Pd particles via the strong coordination with diamine ligands and methyl groups can enhance surface hydrophobicity, weakening the adhesion of NBR/hydrogenated NBR on catalyst and accelerating the desorption of product to re-expose the active sites. The co-functionalized catalyst with small-sized and well-dispersed Pd particles exhibits an enhanced activity and stability, which can be easily recycled by filtration and reused without any treatment. It remains a high activity and 100% selectivity to C=C after recycling 5 times, and only a slight loss of Pd is detected in products. Such catalyst with co-functionalized surface is very efficient for NBR hydrogenation and also can be applied to other catalytic systems to tune their selectivity, activity and reusability.