Directly electrospinning synthesized Z-scheme heterojunction TiO2@Ag@Cu2O nanofibers with enhanced photocatalytic degradation activity under solar light irradiation

Abstract

Electrospinning has become a universal and direct method for the preparation of nanofibers with rich porosity and large specific surface area. In this work, the Z-scheme heterojunction TiO2@Ag@Cu2O nanofibers photocatalyst was prepared via electrospinning and showed excellent visible light catalytic degradation performance with the obtained degradation efficiency of methylene blue as high as 99% within two hours. The main active compounds for the photocatalytic degradation of the dye methylene blue were superoxide radical (•O2−) and hydroxyl radicals (•OH) as well as H+. Compared to pure TiO2, following its combination with Cu2O for visible light absorption, the recombination rate of the photogenerated electron-hole pairs was reduced. After Ag doping, due to the strong surface plasmon resonance absorption effect of Ag, a red shift occurs during the pyrolysis process, showing an outstanding contribution to the effective use of sunlight. Electrochemical test results showed that a Z-scheme hybrid structure was formed in the TiO2@Ag@Cu2O nanofibers. The photocurrent density of TiO2@Ag@Cu2O nanofibers was 3.78 times higher than that of TiO2@Cu2O nanofibers and 47.6 times higher than that of TiO2 nanofibers. The Z-scheme heterojunction not only improved the visible light absorption efficiency, but also separated and transferred carriers, effectively preventing the recombination of photogenerated carriers. Therefore, we believe that TiO2@Ag@Cu2O nanofibers photocatalyst advances the development of photocatalysis technology and is promising for use in a broad range of applications in environmental remediation.