en Research Paper Research Paper Copper oxide (CuO) nanostructure particles were prepared using KOH/NaOH catalyst by low cost precipitation method and characterized by powder X-ray diffraction (PXRD), scanning electron microscope (SEM) and energy dispersive X-ray spectra (EDX) analysis. The photocatalytic dye degradation study of pure CuO nanostructure particles are analysed against two azo dyes (Direct black 38 (Black-E) and Congo red) under ultraviolet (UV) and solar irradiation. The release of major active species (*OH) in the photocatalytic degradation by as prepared CuO nanostructure particles were investigated by photoluminescence (PL) spectra with two different excitation wavelength (325and 355nm). The band gap of CuO nanostructure particles was calculated from diffuse reflectance spectra. The photocatalytic effect of CuO nanostructure particles is confirmed from the UV – Vis and photoluminescence spectra and also, further confirmed from the kinetic studies under UV and solar radiations. The photocatalytic degradation results revealed that 16.35% and 7.5% of black E and Congo red dye was degraded under UV, while it was 47.2% and 17.6% under solar light. The influence of pH on the photodegradation and change in the reaction temperature under solar irradiation were also analysed copper oxide,photocatalytic activity,azo dyes,dyedegradation,precipitation method 1 12 http://ijmse.iust.ac.ir/browse.php?a_code=A-10-3497-1&slc_lang=en&sid=1 Usha Vengatakrishnan ushaias@gmail.com 1800319475328460014375 1800319475328460014375 No ScholarP.G. and Research Department of Physics, Sri Paramakalyani College, Alwarkurichi-627412, India. Kalyanaraman Subramanian kalyan@gmail.com 1800319475328460014376 1800319475328460014376 No P.G. and Research Department of Physics, Sri Paramakalyani College, Alwarkurichi-627412, India. Vettumperumal Rajapand vettumperumalphy@gmail.com 1800319475328460014377 1800319475328460014377 No Department of Physics, Fodhdhoo School, Noonu Attol, 04120 Republic of Maldives. Dhineshbabu Nattanmai Raman babudhinesh2009@gmail.com 1800319475328460014378 1800319475328460014378 Yes Assistant ProfessorDepartment of Electronics and Communication Engineering, Aditya Engineering College, Surampalem, East Godavari Distt.533437, Andhra Pradesh, India