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Updated: Aug 22, 2025
Photodeposition of Pd onto Colloidal Au Nanorods by Surface Plasmon Excitation
Published on: August 15, 2019
Probing catalytic reduction on the surface of Au nanoparticles by second-harmonic generation and two-photon
Shan Xue1,2,3, Shun-Li Chen4, Qunhui Yuan5
1Shenzhen Key Laboratory of Flexible Printed Electronics Technology, also School of Science, Harbin Institute of Technology (Shenzhen), University Town, Shenzhen 518055, Guangdong, China. ganwei@hit.edu.cn.
Abstract:
The catalytic reduction of aromatic nitro compounds by metallic nanoparticles in the presence of sodium borohydride (NaBH4) has been widely studied as model reactions. However, the reaction mechanisms still need further investigations. For example, the origin of the induction time that has often been observed is still controversial. Here, we demonstrated that such catalytic reduction reactions on the surface of colloidal gold nanoparticles (AuNPs) may be inspected by the second-harmonic generation (SHG) and two-photon luminescence (TPL) emission from AuNPs. It was revealed that the SHG and TPL signals from AuNPs were sensitive to the substitution of citrate by active hydride species derived from the hydrolysis of NaBH4. Based on the UV-vis spectroscopy analyses and monitoring the SHG/TPL signals, the induction time in the catalytic reaction of 4-nitrothiophenol was revealed to originate from the hindered adsorption of hydride on the gold surface. This work demonstrated that SHG and TPL can provide a new approach for detecting active hydrides on the surface of metallic nanoparticles in colloids.
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