TiO2@Cu2O n-n Type Heterostructures for Photochemistry

A TiO2@Cu2O semiconductor heterostructure with better photochemical response compared to TiO2 was obtained using an electrochemical deposition method of Cu2O on the surface of TiO2 nanotubes. The choice of 1D nanotubes was motivated by the possibility of achieving fast charge transfer, which is considered best suited for photochemical applications. The morphology and structural properties of the obtained heterojunction were determined using standard methods -SEM and Raman spectroscopy. Analysis of photoelectrochemical properties showed that TiO2@Cu2O heterostructures exhibit better properties resulting from an interaction with sunlight than TiO2. A close relationship between the morphology of the heterostructures and their photoproperties was also demonstrated. Investigations representing a combination of photoelectrochemical cells for hydrogen production and photocatalysis-photoelectrocatalysis-were also carried out and confirmed the observations on the photoproperties of heterostructures. Analysis of the Mott-Schottky plots as well as photoelectrochemical measurements (I-ph-V, I-ph-t) showed that TiO2 as well as, unusually, Cu2O exhibit n-type conductivity. On this basis, a new energy diagram of the TiO2@Cu2O system was proposed. It was found that TiO2@Cu2O n-n type heterostructure prevents the processes of photocorrosion of copper(I) oxide contained in a TiO2-based heterostructure.

Automated summary

A TiO2@Cu2O semiconductor heterostructure was obtained by electrochemical deposition of Cu2O onto TiO2 nanotubes, showing better photochemical response and properties than TiO2. SEM and Raman spectroscopy were used to determine the morphology and structural properties of the heterojunction. The n-n type heterostructure of TiO2@Cu2O was found to prevent the process of photocorrosion of copper(I) oxide in a TiO2-based heterostructure, and a new energy diagram for the system was proposed based on the analysis of Mott-Schottky plots and photoelectrochemical measurements.