A multifunctional Ag/PAOCG reusable substrate for p-nitrophenol reduction and SERS applications

Abstract

We demonstrate a facile galvanic replacement reaction route to direct growth of silver nanoparticles (AgNPs) into porous alumina on conductive glass (PAOCG). Porous Al2O3 layer was prepared by using boehmite as precursor, deposited on conductive glass via spin coating, and followed by a heat treatment. PAOCG was attached firmly with a tiny sheet of steel and was then soaked in AgNO3 solution. Ag+ ions in the nanopores of PAOCG adsorbed by capillarity were automatically reduced to metallic AgNPs, thus forming Ag/PAOCG. The catalytic property of Ag/PAOCG was investigated for p-nitrophenol (PNP) reduction using UV–Vis absorption spectroscopy, and the rate constant was evaluated using the pseudo-first-order kinetic model. This film catalyst could be readily regenerated and reused for up to ten times without significantly depreciate its efficiency. The SERS performance of Ag/PAOCG was investigated using aqueous crystal violet (CV) as a probe molecule. The optimum Ag/PAOCG substrate was capable of detecting as low as 10−10 M aqueous CV. The reusability of Ag/PAOCG was achieved by heating the substrate at 400 °C for 5 min in air. This substrate could be reused for at least five cycles without significantly reduced SERS performance. Therefore, this powerful multifunctional surface can serve as a portable, durable and reusable substrate for PNP reduction and SERS applications.