CuO/ZnO coupled oxide films obtained by the electrodeposition technique and their photocatalytic activity in phenol degradation under solar irradiation Diego S. Paz, Edson L. Foletto, Daniel A. Bertuol, Sérgio L. Jahn, Gabriela C. Collazzo, Syllos S. da Silva, Osvaldo Chiavone-Filho and Claudio A. O. do Nascimento ABSTRACT CuO/ZnO coupled oxide films were electrodeposited onto an aluminum substrate and tested as photocatalysts in degradation of phenol molecules in aqueous solution under sunlight. The obtained films were characterized by X-ray diffraction, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results showed that the photocatalytic activity of films was significant, especially to coupled oxide film with a CuO/ZnO ratio equal to 0.697, which presented about 70% degradation of the aromatic molecules and 42% of total organic carbon (TOC) removal at 300 min under solar irradiation. Therefore, this work highlights the potential application of CuO/ZnO coupled oxide films obtained by electrodeposition onto aluminum substrate in the field of photocatalysis. Diego S. Paz Edson L. Foletto (corresponding author) Daniel A. Bertuol Sérgio L. Jahn Department of Chemical Engineering, Federal University of Santa Maria, 97105-900, Santa Maria, Brazil E-mail: efoletto@gmail.com Gabriela C. Collazzo Department of Chemical Engineering and Food Engineering, Federal University of Santa Catarina, 88040-900, Florianópolis, Brazil Syllos S. da Silva Osvaldo Chiavone-Filho Department of Chemical Engineering, Federal University of Rio Grande do Norte, 59066-800, Natal, Brazil Claudio A. O. do Nascimento Department of Chemical Engineering, University of São Paulo, 05508-900, São Paulo, Brazil Key words | CuO/ZnO, electrodeposition, film, phenol, photocatalysis INTRODUCTION Treatment of pollutants from wastewater using semicon- ductors as photocatalysts has been a promising method among advanced oxidation processes (Fujishima et al. ). Among the several applications of such anode material for lithium-ion batteries, glucose and cholesterol biosensors, photovoltaic devices and solar cells (Wang ; Arya et al. ), ZnO powder has been widely used as a photocatalyst for the degradation of organic pol- lutants in aqueous solutions (Gaya et al. ; Liu et al. ). However, the use of conventional powder catalyst has the disadvantage of the separation and recovery of the powder photocatalyst. An alternative that solves this problem is the use of the photocatalyst in an immobilized form, as it happens to be in a thin film. Different tech- niques have been used to prepare films of semiconductor oxides such as thermal evaporation (Bouhssira et al. ), oxidation and anodizing (Spathis & Poulios ), chemical vapor deposition (Li et al. ), sputtering (Kim et al. ), pulsed laser deposition (Khandelwal et al. ), sol-gel (Sengupta et al. ), spray pyrolysis (Golshahi et al. ) and electrodeposition (Silva et al. ). Compared to other methods, electrodeposition is a simple method, low cost, operates in mild conditions (low temperature and pressure) and is therefore suitable for large-scale production (Xu et al. ). Due to its wide band gap (3.2 eV) (Chen & Zhou ), ZnO semiconductor can only absorb a small part of solar irradiation in the UV region because sunlight con- tains about 4% of UV rays (Tai et al. ). In order to improve the photocatalytic activity of ZnO under solar 1031 © IWA Publishing 2013 Water Science & Technology | 68.5 | 2013 doi: 10.2166/wst.2013.345