1.Department of Cosmetic Science, Providence University, 43301, Taichung, Taiwan ;2.Department of Chemical Engineering, Chung Yuan Christian University, 32023, Taoyuan, Taiwan ;3.Technical Department Plastics Division, Formosa Plastics Corporation, 814538, Kaohsiung, Taiwan ;
Abstract:
Heterogeneous catalysts based on metallic nanoparticles are promising candidates for wastewater treatment. However, they aggregate easily as a result of their high surface energy. Polymers are very popular supporting catalyst materials because they can stabilize the metallic nanoparticles to prevent aggregation. In this study, aniline-pentamer-based electroactive polyurea (EPU) was synthesized by oxidative coupling, and Au nanoparticles were anchored to the EPU via its aniline segments. Electrochemical redox behavior of the as-synthesized EPU was monitored by electrochemical cyclic voltammetry. The Au/EPU composite was characterized by FTIR, UV–vis, TGA, SEM, TEM, XRD XPS, and ICP-OES. SEM showed that the EPU had a flower-like structure, and the Au nanoparticles were uniformly immobilized on the EPU surface. The reduction of 4-nitrophenol (4-NP) by NaBH4 was used as a model reaction to evaluate the catalytic properties of the Au/EPU composite. Moreover, the optimization of the reaction conditions for the reduction of 4-NP to 4-aminophenol (4-AP) were also studied in detail. The Au/EPU composite catalyzed the reduction of 4-NP to 4-AP within 4 min with a rate constant of 2.4?×?10–2 s?1 and an activation energy of 40.17 kJ/mol. The Au/EPU composite demonstrated high conversion (98%) after 20 successive cycles.