Enhanced Catalytic Activities of TiO2 Nanotube Arrays Co-Sensitized with Pt/CdS/ZnS via Electrodeposition and Successive Ionic Layer Adsorption and Reaction (SILAR) Method Approach

In this work, we have synthesized a nanocomposite ZnS/CdS/Pt/TiO2 nanotube arrays (denoted ZCP-NTAs). Firstly, TiO2 nanotube array (NTAs) material was fabricated by the anodic method of a titanium plate in an electrolyte solution containing 0.35 M NaHSO4 and 0.24 M NaF and incubated in the air at 500 ºC for 2 hours. After that, pulsed electrodeposition technology was used to decorate platinum nanoparticles (denoted as Pt NPs) onto the surface of TiO2 nanotubes to form P-NTAs photoelectrodes. Then, the SILAR method is used to deposition CdS quantum dots (symbolized as CdS QDs) on the surface of P-NTAs to form CP-NTAs material. Finally, by the SILAR method, a ZnS passive layer that protects against optical corrosion and inhibits recombination of e−/h+ pairs was coated onto the CP-NTAs to form ZCP-NTAs material. As-prepared ZCP-NTAs photocatalytic material has good absorbability of light in the visible region with light absorption wavelength up to 608 nm, photon conversion efficiency up to 5.32% under light intensity AM1.5G, and decomposition efficiency of 10 mg L−1 methyl orange (MO) in 120 minutes reached 91.50%. This material promises to bring high application ability in the photocatalytic field applied for environmental treatment and other applications.