Investigation of catalytic potential of Au NPs adorned surface modified mesoporous silica towards the reduction of 4-nitrophenol

Abstract

A surface modified heterogeneous silica nanocomposite material was synthesized by supporting Au NPs on the alkyl cyanide functionalized Mesoporous SBA-15. Au NPs were in-situ synthesized by the mild citrate reduction and decorated over the surface of hexagonally ordered mesoporous matrix having dimension within 13.4 ± 2.5 nm. The structural and elemental identity of the hybrid material was investigated by a range of advance methods like HRTEM, EDX, XPS and ICP-AES. The cyano (CN) functionalization played an effective role in stabilizing the NPs. Subsequently, catalytic potential of the nanomaterial was surveyed through the reduction of 4-nitrophenol (4-NP) using sodium borohydride as the hydrogen source. The specific reaction was monitored spectrometrically using a UV–Vis spectrophotometer. Very small amount of catalyst (1.0 mg and 0.1 mol% Au loaded catalyst) was needed to have a high productivity in short time. In addition, kinetic study was followed to determine the relative rate constants. It exhibited pseudo-first-order mechanism and the rate enhanced proportionally with the catalyst load. The nanocatalyst was recycled for ten successive runs with no significant alternation in its reactivity.