Schottky Heterojunction of Core–Shell Cu/CuO/Cu2O for Efficient Photocatalytic Degradation

With the acceleration of industrialization and urbanization, the treatment of organic pollutants in water bodies has become a global problem. Photocatalytic technology is regarded as an ideal solution due to its green and efficient characteristics. However, traditional powder catalysts have the problem of difficult recovery. Using copper foam as the substrate to load photocatalysts is a feasible solution. Cu/CuO/Cu₂O with a core–shell structure was prepared by a simple solvothermal method based on copper foam. Under visible light irradiation, the Cu/CuO/Cu₂O catalyst has a high catalytic efficiency for Congo red (95% within 180 min) and a significant adsorption and degradation ability for tetracycline hydrochloride. The results of the density functional theory calculation and electrochemical tests reveal that a Schottky heterojunction forms between Cu₂O and CuO, the band gap of Cu₂O is 0.57 eV, and the free energy of Cu/CuO/Cu₂O is 0.24 eV, close to 0 eV, revealing the ternary composite’s possibility to evolve hydrogen. The heterojunction generated by Cu₂O and CuO improves the material’s charge transport efficiency. Furthermore, this ternary composite based on copper foam easy to recycle and reuse, and can maintain nearly 90% degradation efficiency after 8 cycles. This concept offers a method for planning and building interfaces in nanocomposite structures.

Graphical Abstract