Synthesis and characterization of Cr-doped ZnO nanorod-array photocatalysts with improved activity

• Cr dopant enhances separation of charge carries in ZnO nanorod photocatalyst.
• Photoinduced charge carries separation monitored by PEC-SECM.
• The higher the photocurrent is, the higher the photocatalytic activity is.
• Degradation of DB86 dye solutions under visible light finished within 50 min.
• Higher activity due to more oxygen vacancy, tuned band gap and more surface area.

Immobilized photocatalysts with high catalytic activity under UV light were prepared by growing Cr-doped ZnO nanorods on glass substrates by a hydrothermal method. The effects of Cr dopant on the surface texture, crystallinity, surface chemistry, and photoinduced charge separation and their relation with the photocatalytic degradation of Cr-doped ZnO were investigated by scanning electron microscopy, diffuse reflectance spectra, photoelectrochemical scanning electrochemical microscopy, and X-ray photoemission spectroscopy. Adding the appropriate amount of Cr dopant is a powerful way to enhance the separation of charge carriers in ZnO photocatalyst. The photocatalytic activity was improved due to the increase in surface oxygen vacancies, the separation of charge carriers, modification of the band gap, and the large surface area of the doped ZnO nanorod photocatalyst.

Photoinduced charge separation and its relation with the photocatalytic degradation activity of Cr-doped ZnO were investigated by photoelectrochemical scanning electrochemical microscopy.Figure optionsDownload as PowerPoint slide