Hybrid paper–TiO2 coupled with a Cu2O heterojunction: an efficient photocatalyst under sun-light irradiation

Abstract

Hybrid paper–TiO₂, paper–Cu₂O–TiO₂ and paper–TiO₂–Cu₂O photocatalysts were prepared via a non-hydrolytic sol–gel process followed by mild hydrothermal treatment to generate the TiO₂ layer, and a reduction process to form the Cu₂O nanoparticles. The hybrid photocatalysts have been characterized by Raman, TGA, FE-SEM, UV-Vis and XPS. The immobilized TiO₂ was found to form a homogeneous thin layer composed of nanoparticles with a size smaller than 10 nm. The Cu₂O nanoparticles with sizes of 30–100 nm were generated either on the top of the TiO₂ layer or by reduction of Cu²⁺ ions. All the prepared hybrid catalysts showed efficient photocatalytic properties for the degradation of toluidine when exposed to simulant solar light. A strong enhancement in the photocatalytic activity was observed when TiO₂ was coupled with the Cu₂O heterojunction, with the highest effect being observed when the Cu₂O NPs were present on top of the TiO₂ layer. The hybrid photocatalyst can be reused for at least four consecutive cycles without a significant decrease in the degradation efficiency. The preparation technique of the hybrid catalyst is reliable, economic, easy to implement and may be scaled to prepare paper–TiO₂ hybrid photocatalysts active under sun-light exposure.