Gold nanoparticles coated silicon nanowires for efficient catalytic and photocatalytic applications

This work is focused on the elaboration of gold (Au) nanoparticles supported silicon nanowires (SiNWs) for catalytic and photocatalytic applications. The SiNWs investigated in this study are synthesized by metal-assisted chemical etching technique, while the gold nanoparticles (AuNPs) are loaded on SiNWs through the redox reaction between HAuCl4 and HF-treated SiNWs. Scanning electron microscopy (SEM), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), and photoelectron spectroscopy (XPS) were used to characterize the morphology, composition and chemical states of the fabricated samples. The catalytic activity of the SiNWs loaded with AuNPs was investigated for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) with sodium borohydride (NaBH4). The photocatalytic activity of SiNWs-AuNPs under visible light irradiation was assessed using Rhodamine B (RhB) as a representative organic dye. The course of the above reactions was monitored by UV-vis spectrophotometry. Our results showed that the SiNWs-AuNPs samples could catalyze the reduction of 4-NP and degradation of RhB with excellent efficiency and stability.