Catalytic activity of silicon nanowires decorated with silver and copper nanoparticles

The paper reports on the elaboration of silicon nanowires decorated with silver (SiNWs–Ag NPs) or copper (SiNWs–Cu NPs) nanoparticles and the investigation of their catalytic properties for the reduction of 4-nitrophenol to 4-aminophenol. The SiNW arrays were produced through chemical etching of crystalline silicon in HF/AgNO₃ aqueous solution. The metal nanoparticles were deposited on the SiNW substrates through chemical bath immersion in a metal salt/hydrofluoric acid aqueous solution. The SiNWs decorated with Ag NPs and Cu NPs were characterized by scanning electron microscopy (SEM), x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS). The catalytic activity of the SiNWs loaded with metal nanoparticles was evaluated for the reduction of 4-nitrophenol to 4-aminophenol in the presence of sodium borohydride (NaBH₄). The substrates exhibited good catalytic performance toward nitrophenol with a full reduction in less than 30 s for the SiNWs–Cu NPs. (paper)