ABSTRACT
In this study, poly(N-isopropylmethacrylamide-co-methacrylic acid) microgels prepared by free radical precipitation polymerization were used as micro-reactors for the synthesis and stabilization of silver nanoparticles. UV-Visible spectroscopy, Transmission Electron Microscopy and Fourier-transform infrared spectroscopy were used to characterize both pure and hybrid microgels. The catalytic reduction of 4-nitroaniline was carried out in the presence of hybrid microgels to test their catalytic activity, and the catalysis mechanism was explored by varying the concentrations of reacting species like 4-nitroaniline and NaBH4, as well as the dose of the catalyst. The kinetic data indicates that this reaction follows pseudo-first order. The variation in apparent rate constant (kapp) with respect to NaBH4 concentration also discloses it to be the following Langmuir–Hinshelwood mechanism. The relationship between catalyst concentration and apparent rate constant was found to be increasing in a linear manner. The data obtained also confirmed that silver nanoparticles loaded microgels have the potential to be used as an excellent micro-reactor for selective reduction of 4-nitroaniline to p-phenylenediamine.
Acknowledgments
Zahoor H. Farooqi and Umar Farooq are highly thankful to Higher Education Commission Pakistan for financial support to carry out this work under National Research Program for Universities (NRPU) (No.20-3995/NRPU/R & D/HEC/14/1212). A. Irfan would like to express his gratitude to Research Centre for Advanced Materials, King Khalid University, Saudi Arabia for support.
Disclosure statement
No potential conflict of interest was reported by the authors.