Efficient Photodegradation of Organic Pollutants By Using a Bi2CuO4/BiPO4 Heterojunction Photocatalyst

Abstract Photocatalysis is the most promising and cheap route for water purification. In this work, we demonstrate the degradation of organic pollutants, such as picric acid and methylene blue, by an efficient, reusable Bi 2 CuO 4 /BiPO 4 heterojunction photocatalyst. The Bi 2 CuO 4 /BiPO 4 heterojunction was fabricated using a solvothermal method followed by sonication. The Bi 2 CuO 4 /BiPO 4 heterojunction shows enhanced photocatalytic degradation of picric acid and methylene blue dye under ultraviolet‐visible (UV/Vis) light compared to its individual constituents as well as compared to the previously reported Bi 2 CuO 4 ‐based photocatalyst. The high photocatalytic activity of the Bi 2 CuO 4 /BiPO 4 heterojunction can be attributed to the enhanced separation efficiency of the photogenerated electron and hole pairs. The photocatalytic activity of the Bi 2 CuO 4 nanostructures, which is generally weak due to faster recombination of the electron and hole, is enhanced by means of heterojunction formation with BiPO 4 nanocrystals. Interestingly, the hydroxyl radical, which was found to be the primary active species, is not generated at the valence band due to thermodynamic constraints. In contrast, experiments carried out under controlled conditions unequivocally confirm that their generation is related to oxygen reduction at the conduction band.