Kinetic studies of catalytic reduction of 4-nitrophenol with NaBH4 by means of Au nanoparticles dispersed in a conducting polymer matrix

In this work, we present a method of obtaining of effective catalytic system composed of conducting polymer, poly(1,8-diaminocarbazole) (PDACz), with Au nanoparticles (AuNPs) of diameter 2 nm uniformly dispersed in the polymer matrix. Reduction of 4-nitrophenol (4-NPh) by NaBH4 with the use of this catalyst was studied by means of UV-Vis spectroscopy. It was shown that the catalytic reaction obeys either pseudo-zero-order or first-order kinetics, depending on the concentration of 4-NPh in the solution at excessive amount of borohydride. The catalytic activity of PDACz/AuNP system is discussed in terms of amount of deposited nanoparticles and the number of consecutive catalytic cycles. The kinetic data are correlated with scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images of the system before and after catalytic process.