Self-supported Ag/AgCl nanoparticles incorporated polymeric multilayer films for reusable electrophotocatalyst

We describe here, synthesis and electrophotocatalytic activity of the nanocomposites of Ag/AgCl embedded in polymeric matrix. The nanocomposites were synthesized through a sequence of steps. First, polyelectrolyte multilayer (PEM) films of poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA) were formed on ITO or glass slides. The multilayered films were then dipped into an aqueous solution of silver nitrate (AgNO₃) under ambient conditions to incorporate Ag⁺ ions into the PEM films, in which Ag+ ions combine with Cl⁻ ions of PAH to form AgCl nanoparticles. A part of AgCl was partially reduced by PAH to form metallic Ag in contact with AgCl. The composite materials were characterized by several microscopic and spectroscopic techniques. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) proved the simultaneous presence of Ag+ ions and metallic Ag in the films. The amount of Ag in the films was also quantified with inductively coupled plasma optical emission spectroscopy (ICPOES). The nanocomposites found application towards electrophotocatalytic degradation of the dye of methylene blue. Multiple hetero-junctions created in the ternary composite synergistically enhance the photocatalytic activity. Since the catalyst is prepared in the form of film, it can be readily separated from the experimental set up and can be reused. As a result, it shows minimum loss of catalytic activity after five cycles. In addition, the catalyst can degrade colorless organic contaminant of 2-chlorophenol.