One-Step and Surfactant-Free Fabrication of Gold-Nanoparticle-Decorated Bismuth Oxychloride Nanosheets Based on Laser Ablation in Solution and Their Enhanced Visible-Light Plasmonic Photocatalysis.

A simple synthetic route is presented for fabricating gold nanoparticle (NP)-decorated bismuth oxychloride (BiOCl) nanosheets in one step based on laser ablation of a gold target in a hydrochloric acid solution of bismuth nitrate without surfactant. After laser ablation, BiOCl nanosheets with attached Au NPs are obtained. The nanosheets are sub-micron in the planar dimension and around 20 nm thick, and the Au NPs are a mean size of approximately 20 nm. Further experiments reveal that such Au-NP-decorated nanosheets could be formed at a large Cl/Bi molar ratio range (0.01 to 3) in solution. The formation of the BiOCl nanosheets is attributed to the Au plasma plume-induced local fast hydrothermal reaction, which drives the planar growth of BiOCl. Importantly, these Au-NP-decorated BiOCl nanosheets exhibit high photodegradation activity on rhodamine B, a typical organic pollutant, compared with bare nanosheets under visible light irradiation, and show highly stable and recyclable performance. This is attributed to the plasmonic properties of Au NPs, which increase optical absorption and promote separation of electron-hole pairs in the NP-decorated BiOCl nanosheets. This work provides not only a new plasmonic photocatalyst for the oxidative degradation of organic pollutants, but also a general method for fabrication of the metal-NP-decorated nanosheets of other layer-structured oxychlorides.