Nanogold embedded Co3O4 spinel supported over SBA 15 for the reduction of aquatic pollutant 4-nitrophenol

Reduction of 4-nitrophenol to 4-aminophenol is carried out over nanogold doped cobalt loaded SBA 15 catalysts in aqueous solution at room temperature using alkaline NaBH4 as the reductant. XRD and FTIR analysis of the catalysts showed the existence of Co as Co3O4 spinel structure. The efficient dispersion of nanogold particles as suggested by X-ray diffraction patterns was evident from TEM photographs. SAED patterns of the 2 wt% Au doped Co loaded SBA 15 revealed the presence of amorphous SBA 15, single crystalline Co3O4 and polycrystalline Au nanoparticles over Co3O4. The catalyst systems performed very well and the nitrophenol reduction occurred within 35 s over the 2 wt% Au doped Co/SBA 15, once the reactant mixing was over. An increase in the catalyst dosage resulted in very fast reduction and complete conversion occurred at the instant of substrate addition to the reductant–catalyst mixture. This methodology can be widely applied for the complete removal of water pollutant 4-nitrophenol.