Synthesis of CuCr2O4 by self-combustion method and photocatalytic activity in the degradation of Azo Dye with visible light.

• The synthesis of CuCr 2 O 4 by the self-combustion method is simple and promising showing great yield. • The CuCr 2 O 4 presented a bandgap of 1.25 eV, proving to be ideal for the degradation of the azo dye under visible radiation. • The studies show that it was possible to degrade 99,6% of the azo dye using CuCr 2 O 4 and in the absence of H 2 O 2. Azo dyes are dangerous and notorious environmental pollutants because are difficult to degrade and can form highly toxic products. The degradation of those compounds is of extreme interest and widely studied. At this point, the heterogeneous photocatalysis, an advanced oxidation process (AOP), gains prominence in the degradation of persistent compounds. This study presents the synthesis of CuCr 2 O 4 spinel by the self-combustion method and the photocatalytic activity in the degradation of tartrazine azo dye. The sample was synthesized by self-combustion reaction, which seems to be a simple, efficient and fast process. The sample was characterized, and the results show high purity, homogeneity and great capacity in the degradation in visible light, with a bandgap of 1.25 eV. A factorial design was performed to study the influence of the pH of the solution and the amount of photocatalyst used, and the results showed better performance at pH 3.0 and 0.5 g of CuCr 2 O 4. The photocatalyst proved to be efficient and promising, presenting 99.6 % azo dye degradation in 120 min under visible radiation. [ABSTRACT FROM AUTHOR]