Novel Sr–Au–ZnO: Synthesis, characterization and photocatalytic activity

•A simple method adopted for the synthesis of novel Sr–Au–ZnO.•The surface area and pore volume of Sr–Au–ZnO are almost twice when compared to bare ZnO.•Sr–Au–ZnO is most efficient than all other prepared and commercial catalysts.

A simple method was adopted for the synthesis of Sr–Au–ZnO and the formed composite was characterized by different characterization technique. The initial dopant amount of Au was fixed as a constant, the other dopant amount (Sr) was varied. It is good to keep the concentration of Au in a minimum level due to its cost. The optimization of Sr amount was performed through the photocatalytic activity of the prepared catalysts using AR 18 degradation under UV-A light. The photocatalytic activity was highly influenced by Sr. The optimized Sr–Au–ZnO was found to be more efficient than single metal dopants (Sr–ZnO, Au–ZnO), commercial catalysts (ZnO and benchmark photocatalyst Degussa P25) and prepared ZnO for the mineralization of AR 18. The effects of operational parameters such as the amount of photocatalyst, dye concentration, initial pH on photo mineralization of AR 18 have been analyzed and optimized values are reported. The mineralization of AR 18 has been confirmed by COD measurements. A mechanism has been proposed for the degradation of AR 18 by Sr–Au–ZnO under UV-A light illumination. Reusability of optimized Sr–Au–ZnO, make this process to be applied for industrial effluent treatment.

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