Highly stable and efficient gold nanoparticles films facilitated by thiourea for catalytic reduction of nitrophenol in water

Abstract

Water pollution from nitrophenol, a common nitrogen-containing aromatic pollutant, is becoming increasingly significant. Making the conversion of nitrophenol to the less toxic and more easily biodegradable aminophenol is a promising strategy to treat industrial wastewater. A simple and efficient method for treating nitrophenol was investigated using gold nanoparticles (AuNPs) with thiourea and fabricating AuNPs films via filtration for the first time. The prepared AuNPs film with nanoporous structure exhibits good structural stability and excellent catalytic activity. The results show that the optimal concentration of adding thiourea is 20 μg/mL, and the optimal concentration of adding NaBH4 is 1000 mM. After treatment with 20.0 μg/mL thiourea, the prepared AuNPs film catalyzes the degradation of 1.0 mM 2-nitrophenol to 2-aminophenol in just 150 sec. The AuNPs film provides a high density of active sites at the interface, and its stable nanoporous structure brings the substrate nitrophenol closer to the active center, thus enhancing the efficiency of catalytic reduction. Besides, the AuNPs films treated with thiourea still maintained good catalytic performance after seven cycles of catalysis and the catalytic efficiency is still as high as 90%. The thiourea-treated AuNPs film sets a precedent for the innovation of novel catalysts that is a very promising industrial strategy for reducing nitrophenol to aminophenol, offering significant economic advantages.