Cu2O/TiO2 heterostructure nanotube arrays prepared by an electrodeposition method exhibiting enhanced photocatalytic activity for CO2 reduction to methanol

Cu2O/TiO2 composite nanotube arrays demonstrating enhanced photocatalytic performance were synthesized using an electrodeposition method to impregnate the p-type Cu2O into the n-type titanium dioxide nanotube arrays (TNTs). The morphological results confirmed that the TNTs are wrapped by the Cu2O nanoparticles and the UV–Vis absorption spectra showed that the Cu2O/TNTs display a better ability for visible light absorption compared to the pure TNTs. CO2 photocatalytic reduction experiments carried out by using Cu2O/TNT nanocomposites proved that Cu2O/TNTs exhibit high photocatalytic activity in conversion of CO2 to methanol, while pure TNT arrays were almost inactive. Furthermore, Cu2O/TNTs also exhibited augmented activity in degradation of target organic pollutant like acid orange (AO) under visible light irradiation. The ultra enhanced photocatalytic activity noticed by using Cu2O/TNTs in CO2 reduction and degradation of organic pollutant could be attributed to the formation of Cu2O/TiO2 heterostructures with higher charge separation efficiency.