Shenzhen Key Laboratory of Flexible Printed Electronics Technology, also School of Science, Harbin Institute of Technology (Shenzhen), University Town, Shenzhen 518055, Guangdong, China.
School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, Heilongjiang, China.
Phys Chem Chem Phys. 2022 Nov 23;24(45):27900-27907. doi: 10.1039/d2cp03613d.
The catalytic reduction of aromatic nitro compounds by metallic nanoparticles in the presence of sodium borohydride (NaBH) 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 NaBH. 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.
在硼氢化钠 (NaBH) 的存在下，金属纳米粒子催化还原芳香族硝基化合物已被广泛研究作为模型反应。然而，反应机制仍需要进一步研究。例如，经常观察到的诱导时间的起源仍然存在争议。在这里，我们证明了在胶体金纳米粒子 (AuNPs) 表面上的这种催化还原反应可以通过金纳米粒子的二次谐波产生 (SHG) 和双光子发光 (TPL) 发射来检查。结果表明，来自 AuNPs 的 SHG 和 TPL 信号对源自 NaBH 水解的活性氢化物取代柠檬酸敏感。基于紫外-可见光谱分析并监测 SHG/TPL 信号，揭示了 4-硝基噻吩在催化反应中的诱导时间源自氢化物在金表面上的吸附受阻。这项工作表明，SHG 和 TPL 可以为检测胶体中金属纳米粒子表面上的活性氢化物提供一种新方法。
