Fast In Situ Metal Deposition and Removal Under UV and Visible Light Using Polydopamine/TiO2 Composite Surface

Metal nanoparticles (MNPs) stand out owing to conspicuous catalytic activity, optical and electromagnetic properties, with applications ranging from photocatalysis to biosensor and photoelectric devices. Although photocatalysis with TiO2 has emerged as a promising technique for preparing MNPs, the low photocatalytic efficiency of TiO2 limits its practical utilization. Herein, a rapid photoreduction approach is presented to prepare MNPs under UV and visible light based on polydopamine (PDA)/TiO2 composite surface. It found that the PDA‐modified TiO2 substrate can greatly enhance the photocatalytic efficiency and stability of MNPs, leading to rapid and highly‐controllable preparation of MNPs. By this method, various Ag, Au, and Pd patterns with controllable metallization degree can be easily fabricated. In addition, the substrate can be effectively recycled through rapid photobleaching. This method will have a promising future in the preparation of MNPs for various applications.