Amine-functionalized ZSM-5-supported gold nanoparticles as a highly efficient catalyst for the reduction of p-Nitrophenol

The pollution of the aquatic environment is still a concern for researchers in this era of industrial development that must be adequately addressed to prevent damage to the ecosystem. One of the pollutant materials was p- nitrophenol (PNP), which is highly toxic to humans and nature. PNP can be reduced to p-aminophenol (PAP), which is relatively safe for the environment and beneficial for drug synthesis. Herein, we studied hybrid Au nanomaterial as a heterogeneous catalyst for transforming PNP to PAP. The Au nanoparticle was supported on zeolite ZSM-5 by organosilane, i.e., (3-Aminopropyl)-triethoxysilane (APTES). The use of APTES (Au/APTES-ZSM-5) resulted in a smaller gold nanoparticle with an average size of -3 nm, compared to Au/ZSM-5 with an average gold nanoparticle size of -15 nm. In addition, the leaching test also showed that Au/APTES-ZSM-5 was more stable than Au/ZSM-5, as APTES could improve the interaction between Au and ZSM-5. The kinetic tests showed that the Au/APTES-ZSM-5 is more effective in catalyzing the reduction of PNP to PAP, as indicated by a higher rate constant (kobs = 6.00 x 10-1 min-1) compared to that of Au/ZSM-5 (kobs = 1.13 x 10-1 min-1). Ultimately, the reaction mechanism applied in this study follows the Eley-Rideal mechanism, in which PNP is adsorbed on the catalyst surface before reacting with NaBH4 to produce p-aminophenol.

Automated summary

In this study, hybrid Au nanomaterial was used as a heterogeneous catalyst to transform the highly toxic p-nitrophenol (PNP) into a less harmful and useful compound, p-aminophenol (PAP). The results showed that using APTES as a support for Au nanoparticles (Au/APTES-ZSM-5) resulted in a more stable catalyst with a higher reaction rate compared to Au/ZSM-5. This research has important implications for addressing pollution in aquatic environments.