Silver and zirconium mono- and bi-metallic silica mesoporous functionalized PDA materials as highly efficient reusable catalyst for reduction of 4-NP to 4-AP

Abstract

Silver and zirconium mono- and bimetallic SBA-15 catalysts were synthesized in presence of polydopamine (PDA) via hydrothermal method and tested in reduction reaction of 4-nitrophenol. The characteristic peaks of SBA-15 were obtained in accordance with the literature. The use of metal and PDA did not deteriorate the structural properties of SBA-15. From wide-angle XRD diffraction patterns, while the silver peaks were observed in the catalysts, the zirconium peaks were not observed. TEM images showed that metals were settled as nanoparticles except for Zr@SBA-15(P). The highest surface area (1882 m2/g), pore volume (3.18 cm3/g) and pore diameter (7.84 nm) values were obtained for Zr@SBA-15(P). XPS spectra of all catalysts showed that the metals were embedded in the structure in metallic form. Reaction rate constant for Ag@SBA-15(P) was determined as 0.138 min−1 and even after 5 runs its conversion efficiency was about 90%.