Indium Hydroxide/Silver/Carbon Nanocomposite: Synthesis via Galvanic Reaction between In Nanoparticles and Silver Nitrate, Characterization and Its Photocatalytic Activity

Sub-10 nm indium metal nanoparticles (In NPs) stabilized on conductive carbon were reacted with silver nitrate in dark in water at room temperature in a galvanic replacement manner to produce indium hydroxide/silver/carbon nanocomposite (In(OH)₃/Ag/C). The chosen carbon imparted colloidal stability, high surface area and water dispersibility suitable for photodegradation of harmful dyes in water. The size and shape of indium hydroxide and silver nanoparticles produced were found to be similar to that of the In NPs started with. The nanocomposite was characterized by Transmission Electron Microscopy (TEM), Energy Dispersive X-ray Spectroscopy (EDAX), Powder X-Ray Diffraction (PXRD) and Thermogravimetric Analysis (TGA). The galvanic reaction between In NPs and silver nitrate was tracked with UV-Vis Spectroscopy in a control experiment without conducting carbon to confirm that the reaction was indeed thermodynamically spontaneous as indicated by the positive electromotive force (EMF) of +1.14 V calculated for In/Ag⁺ redox couple. The nanocomposite’s photocatalytic performance was evaluated to be 90% under UVC radiation when 10 ppm of methylene blue and 13 wt% of indium hydroxide/silver loading on carbon were used.