Balance of Electroplating and Electrophoresis for Construction of Robust Photocatalytic Copper–titanium Dioxide Composite Coating

Abstract

Cu-TiO₂ composite coatings have attracted extensive attention due to their combination of the excellent electrical conductivity and ductility of metals with the unique properties of the reinforcing phases, etc. However, the improvement of wear resistance, interfacial solid content, and photocatalytic activity of composite coatings are remaining challenges. In this work, a Cu-TiO₂ composite coating with enhanced wear resistance by electroplating of Cu²⁺ and electrophoresis of TiO₂ nanoparticles is prepared. It is intriguing to find that there is an optimal interfacial solid content of TiO₂ for Cu-TiO₂ composite coating with low surface roughness at the electroplating voltage of 2.6 V, the pH of 4, the duration of 10 min, and the TiO₂ nanoparticle concentration of 1 g L⁻¹. A balance mechanism for electroplating and electrophoresis is proposed indicating the deposition of TiO₂ nanoparticles and the reduction of copper ions on the substrate is competitive. Based on the Cu-TiO₂ composite coating, the photocatalytic degradation performance of various organic compounds under UV light is studied, indicating increased hardness and significantly enhanced photocatalytic degradation performance. The degradation efficiency and universality of the Cu-TiO₂ composite coatings are further explored, revealing that various organic dyes can be effectively degraded to below 5% within 24 h.