Effect of Zn nanoparticles morphology on the photoelectrochemical properties of Zn/TiO2NTs nanocomposites

Zn nanoparticles with different size and distribution were loaded on/into TiO2 nanotube arrays (Zn/TiO2NTs) via pulsed electrodeposition method. The morphology of Zn/TiO2NTs was studied by field emission scanning electron microscopy (FESEM). The morphology influence of Zn nanoparticles on the photoelectrochemical properties of Zn/TiO2NTs were investigated by UV–vis diffuse reflectance spectrum (UV–vis DRS) and photoelectrochemical measurements. The results showed that Zn/TiO2NTs composites with an average size at 40–50 nm and uniformly distributed of Zn nanoparticles possessed the narrowest band gap, the best photocurrent response, the highest charge carriers density and minimum charge-transfer resistance. These discrepancies in photoelectrochemical properties of different Zn/TiO2NTs samples can be ascribed to the size and distribution effect (morphology effect) of Zn nanoparticles which can influence the transfer and separation of photo-induced carriers generated by TiO2NTs.

► Zn nanoparticles with different size and distribution were loaded on TiO2NTs.
► Photoelectrochemical properties of different Zn/TiO2NTs were evaluated.
► Zn/TiO2NTs showed optimal properties when abundant Zn–TiO2 contact interfaces formed.