Reduction of 4-nitrophenol to 4-aminophenol using a novel Pd@Ni x B–SiO 2 /RGO nanocomposite: enhanced hydrogen spillover and high catalytic performance

A nanocomposite catalyst containing palladium–nickel boride–silica and reduced graphene oxide (Pd@Ni x B–SiO 2 /RGO, abbreviated as Pd@NSG) was successfully fabricated and its enhanced hydrogen spillover mechanism and high catalytic performance towards reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) is discussed. The structure, composition and morphology of the Pd@NSG nanocomposite were characterized by various techniques. The H 2 adsorption experiment directly reveals the spillover effect on the Pd@NSG nanocomposite and its enhanced H 2 uptake capacity (0.7 wt%) compared to SiO 2 /RGO (0.05 wt%) under 50 bar pressure at RT. 4-NP reduction reaction shows remarkably high activity (120 s) of Pd@NSG compared to Ni x B–SiO 2 /RGO (7200 s) with excellent stability up to 5 cycles. Both the experiments showed the facile H 2 dissociation on the Pd (active sites) activator and subsequent transportation of hydrogen atoms on receptor sites.