Reduction of aromatic nitro compounds on colloidal hollow silver nanospheres

Hollow silver nanospheres colloids were successfully prepared by a simple reaction of silver nitrate (AgNO3), sodium hydroxide (NaOH) and hydroxylammonium hydrosulfate ((NH2OH)2·H2SO4) in the presence of gelatin. Formations of colloidal hollow silver nanospheres were observed by UV–vis absorption spectroscopy, particle size analyzer and transmission electron microscopy (TEM) and X-ray diffraction (XRD). Dispersion destabilization of nanospheres colloids was detected by Turbiscan. Superior catalytic performance was observed in a test reaction of 4-nitrophenol (4-NP) and 4-nitroaniline (4-NA) reduction in the presence of freshly prepared ice cold aqueous solution of sodium borohydride (NaBH4) at room temperature. The reduction process was monitored by UV–vis absorption spectroscopy. The reaction followed pseudo-first order kinetics with respect to nitro compound and the rate constant was found to be larger compared to other silver catalyst used for the reduction reaction.

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► Preparation of stable colloidal hollow Ag nanospheres.
► Catalytic activity was examined by the reduction of 4-NP and 4-NA.
► Reaction followed pseudo-first order kinetics with respect to nitro compound.
► Higher temperature, concentration of NaBH4 and Ag increased the reaction rate.