Facile synthesis of core-shell ZnO/Cu2O heterojunction with enhanced visible light-driven photocatalytic performance

As p-n heterojunction photocatalysts usually possess dramatically improved photocatalytic activity than single photocatalysts, a novel ZnO/Cu2O heterojunction was designed by a facile self-templating method in this study. The crystal structure, chemical composition, surface morphology, and optical property of ZnO/Cu2O heterojunction were investigated to clarify the structure-property correlation. Scanning electron microscope and transmission electron microscope images proved the uniform core-shell submicrospheres of ZnO/Cu2O, in which a three-dimensional flower-like ZnO core was coated by a shell comprised of Cu2O nanoparticles. The photoresponse result showed that the band gap of the ZnO/Cu2O core-shell submicrospheres became narrow, and the absorption edge shifted from the ultraviolet region (380nm) to the visible region (500nm) compared with the pure ZnO microflowers. For the degradation of Rhodamine B under visible light, the photocatalytic efficiency of ZnO/Cu2O submicrospheres reached 96% within 40min of reaction time, which was 3.8 times higher than that of pure ZnO microflowers and up to 4.5 times than that for pure Cu2O nanoparticles. The remarkable visible light-driven photocatalytic performance is mainly attributed to the extended photoresponse range and effective separation of the photo-generated electron-hole pairs in the unique heterojunction. [GRAPHICS] . HighlightsA novel core-shell ZnO/Cu2O heterojunction was synthesized by a facile self-templating method.Core-shell ZnO/Cu2O submicrospheres were comprised of three-dimensional flowerlike ZnO core coated by a shell of Cu2O nanoparticles.The band gap of ZnO/Cu2O submicrospheres became narrow and the absorption edge shifted to the visible region.ZnO/Cu2O submicrospheres exhibited better visible light-driven photocatalytic performance than pure ZnO or Cu2O.