Cu2O@Cu-composed hollow spheres capable of generating rich reactive oxygen species for efficient photodynamic antibacterial application

Cuprous oxide (Cu 2 O), which has an appropriate band gap, is widely used as a marine antifouling biocide. This makes it increasingly valuable for photocatalytic antibacterial applications. Using crystal engineering technology to create Cu 2 O with tailored Cu 2 O/Cu interfaces and crystal planes can effectively enhance its performance but presents challenges. Herein, we report a simple wet chemical method for the controlled preparation of Cu 2 O@Cu hollow heterostructure. Experimental results demonstrate that the prepared composites exhibited highly efficient and broad-spectrum photocatalytic antibacterial effects against both Gram-negative and Gram-positive bacteria, achieving 100% antibacterial efficiency under 10 min of irradiation, much more effective than the bulk Cu 2 O. Characterization results show that a hollow spherical structure consisted of fine Cu 2 O@Cu nanoparticles in their wall, and the generated interfaces facilitated the migration and separation of photogenerated charge carriers and promoted the formation of hydroxyl radicals with stronger oxidizing abilities. Meanwhile, the Cu outside layer of each Cu 2 O@Cu particle not only acted as a shield to protect Cu 2 O from corrosion but also served as an electron acceptor to efficiently transfer photogenerated electrons, thereby demonstrating highly effective and stable antibacterial performance. This study not only offers a valuable reference for developing highly efficient and universal photocatalytic materials but also provides insight into the chemical reaction in the photocatalytic antibacterial process.