TiO2/rGO/Cu2O ternary hybrid for high-performance photoelectrochemical applications

Abstract

In this paper, TiO2 was hybridized with Cu2O and reduced graphene oxide (rGO) in order to increase the light absorption range and improve the photoelectrochemical (PEC) activity of TiO2. The TiO2 powder (P25) was added to an aqueous GO colloidal solution, and then heated in an autoclave to attain the binary TiO2/rGO hybrid. The ternary hetero-nanostructure was achieved through the growth of Cu2O nanoparticles on the TiO2/rGO hybrid by a chemical bath deposition process. The characteristics of TiO2/rGO/Cu2O hybrid powders were investigated through XRD, SEM, TEM, HRTEM, EDS, Raman spectroscopy, FT-IR, PL, and UV–Vis/DRS techniques. The PEC behavior of the ternary hybrid electrode was examined using linear sweep voltammetry, amperometry, and electrochemical impedance spectroscopy tests. The results reveal that TiO2 nanoparticles are well placed on the rGO nanoplatelets while Cu2O nanoparticles are distributed on the binary hybrid. With the addition of Cu2O and rGO, the band-gap energy of TiO2 is reduced from 3.3 eV to 2.72 eV. The PEC test results indicate that the photoelectrochemical activity of the TiO2/rGO/Cu2O ternary hybrid is much higher than that of the bare TiO2 or the TiO2/rGO binary hybrid. The mechanisms responsible for the enhanced PEC behavior of the TiO2/rGO/Cu2O ternary hybrid are discussed in detail.