Selective laser-induced preparation of metal-semiconductor nanocomposites and application for enhanced photocatalytic performance in the degradation of organic pollutants

Abstract

By selective laser-induced in a liquid medium, the metal-semiconductor nanocomposites were prepared, and its photocatalytic performance in the degradation of organic pollutants was evaluated. During the preparation, silver (Ag) and zinc oxide (ZnO) nanoparticles were employed as an example to construct the colloidal precursors and selectively heated under a laser beam unfocused irradiation. After that, the structures, morphologies, optical properties of the prepared nanocomposites were characterized by the XRD, STEM, EDX, UV-Vis and PL instruments, respectively. The results showed that the Ag/ZnO nanocomposites were successfully prepared under the selective laser-induced in a liquid phase, and the composite interfaces of crystal lattice between Ag and ZnO were observed. In addition, the methylene blue (MB) water solution was employed as a model system to check the difference of photocatalytic performance for pure and laser-induced composite catalysts. The results indicated the photocatalytic performance for laser-induced preparation of Ag/ZnO nanocomposites was enhanced two times than the pure photocatalyst of ZnO in the degradation of MB water solution, with a higher rate constant of 0.04 min−1. The corresponding mechanism for enhanced photocatalytic performance can be obtained from the optical properties of nanocomposites, and originated from the laser-induced formation of heterojunction by contact and fusion of Ag and ZnO, with a high electron transfer efficiency and benefit for the degradation. The method and results reported here possess great potential in future application of environmental remedies and other catalysis fields.