Controllable fabrication of immobilized ternary CdS/Pt–TiO2 heteronanostructures toward high-performance visible-light driven photocatalysis

Abstract

Immobilized TiO₂ nanotube arrays (NTAs) co-modified with Pt and CdS nanoparticles were fabricated by using the combination of photoreduction and chemical bath deposition methods. XRD, SEM, TEM, XPS, UV-Vis and EDX methods were employed to characterize the microstructure and composition of samples, and the results showed that CdS and Pt NPs were uniformly deposited on the surface of TiO₂ nanotubes. The CdS/Pt/TiO₂ NTAs exhibited a much higher photocatalytic activity compared to pure TiO₂ NTAs and binary CdS (or Pt)/TiO₂ NTAs under visible light irradiation. A kinetic study showed that the rate constants of Pt/TiO₂, CdS/TiO₂ and CdS/Pt/TiO₂ NTAs are 0.00736, 0.01717 and 0.02077 min⁻¹, respectively, revealing a remarkable kinetic enhancement in the ternary heteronanostructures due to the synergistic effect of the three components. Besides, the CdS/Pt/TiO₂ NTAs exhibit high stability after being used 22 times. Thus we proposed that such ternary heteronanostructures show great promise as immobilized catalysts for high efficient visible-light-driven photocatalysis.