A Facile Electrochemical Approach To Form TiO2/Ag Heterostructure Films with Enhanced Photocatalytic Activity

We report a simple but novel technique to prepare chemically durable TiO2/Ag films on FTO substrates via coating of P25 TiO2 with colloidal silica as a high temperature binder and subsequent electrochemical deposition of silver nanoparticles (AgNPs). The porous nanostructure facilitated implantation of AgNPs by electrochemical deposition. Extensive measurements on photocatalytic activities of the films prepared under varied conditions showed that TiO2/Ag enhanced MB degradation. Possible mechanisms of such enhancement were discussed in terms of delayed recombination of photogenerated electrons/holes via Schottky barriers and beneficial effects of Surface Plasmon. Experimental results of both electrochemical impedance spectra and transient photocurrent responses on the films supported the observed photocatalytic enhancement by TiO2/Ag heterostructures. The study offers an effective technique to implant uniformly dispersed AgNPs around 3 nm in size within a porous structure and may also provide a strategy for preparations of other functional films on FTO substrates.