Rapid hydrogenation: perfect quasi architecture (Ag@SiO2NPs) as a substrate for nitrophenol reduction

Abstract

Spherical nanoparticles with core-frame architecture are a viable route to combine multiple functionalities on a nanoscopic scale. Amongst these nanoparticles, metal polymeric hybrid nanostructures exhibit significantly enhanced stability. Synergistic catalytic responses arise from quasi perfect morphology and their unique interactions between the metal and reactant substrate. Core-frame silver supported silica nanoparticles (Ag@SiO₂NPs) with different frame thicknesses were tailored in a controlled manner through an oversimplified environmentally friendly route using simple chemical additives instead of dendrimers as linkers for prior modification of AgNPs. Here the optical and thermal properties of Ag@SiO₂NPs were studied by high resolution transmission electron microscopy (HRTEM), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The resulting stabilised nature of Ag@SiO₂NPs, their functionalization and environmental behaviour were analysed in detail through absorbance measurements. The control over the particle geometry provided an opportunity to utilise this hybrid NP as a temper for faster hydrogenation of p-nitrophenol with minimal reductant concentration (3 mM NaBH₄). The effect of the volume ratio of the hybrid catalyst with respect to thermal behaviour and their hydrogenation reaction time, average reaction rate and hybrid reusability were thoroughly investigated. The reported high performance towards faster hydrogenation was completed within 300 s at 25 °C and 16 s at 60 °C. The synergetic behaviour of core-frame morphology provides faster electron transfer for hydrogenation and enhanced thermal stability against poisonous environments.