Palladium–Copper\nAlloy Nanoparticles Supported\non Carbon Nitride Nanosheets as a Photocatalyst for Degradation of\nCiprofloxacin

Optimization\nregarding the electronic structure of nanometal\ncocatalysts\nvia alloying is considered as a promising strategy to regulate the\nformation of reactive oxygen species (ROS) in photocatalytic degradation.\nHerein, a series of g-C<sub>3</sub>N<sub>4</sub>-supported PdCu alloy\ncocatalysts were constructed to investigate the regulatory effect\nand mechanism of alloying on photocatalytic active species. Photocatalytic\ndegradation experiments using ciprofloxacin (CIP) as a model pollutant\ndemonstrated that optimal alloying with PdCu (Cu ≤ 0.5 wt %)\nsignificantly boosts the production of active species and incrementally\nenhances the contribution of superoxide anions (·O<sub>2</sub><sup>–</sup>). The introduction of Cu leads to the redistribution\nof surface electrons in the PdCu alloy, resulting in a gradual strengthening\nof the O<sub>2</sub> adsorption as the Cu content increases up to\n0.5 wt %. The CIP degradation rate reaches a maximum of 80.5% at pH\n6.7. Inorganic ions such as Na<sup>+</sup> and Ca<sup>2+</sup> inhibit\ndegradation, while low concentrations of Fe<sup>3+</sup> promote that.\nThe CIP degradation rate in actual water samples ranges from 71.1\nto 78.2%. Furthermore, the degradation pathway initiated from carbonyl\ndestruction induced by a higher ·O<sub>2</sub><sup>–</sup> concentration was proposed. This comprehensive study provides valuable\ninsights into the design of alloyed photocatalysts, emphasizing the\nsignificance of optimizing metal composition to regulate ROS generation\nand enhance photocatalytic efficiency.