铂纳米颗粒的可见光化学制备及其对p-硝基苯酚催化还原反应

在可见光照射下，以乙二醇（EG）作为还原剂和稳定剂，在多壁碳纳米管（MWCNTs）上一步合成了铂纳米颗粒，成功制备Pt/MWCNTs复合材料，并通过p-硝基苯酚（p-NP）的催化还原反应研究了Pt/MWCNTs的催化性能。用傅里叶变换红外光谱（FT-IR）、X射线衍射（XRD）、透射电子显微镜（TEM）和X射线光电子能谱（XPS）对所制备材料的形貌和晶体结构进行了表征。实验结果显示，可见光照射促进了EG水溶液中PtCl₄]^2-前驱体的水解。通过金属界面的电子效应，铂前驱体被还原成了均匀分散的平均直径2.1 nm的超小颗粒Pt（Pt ultra-small particles，Pt UPs）。所制备的Pt/MWCNTs能有效地催化p-NP还原为p-氨基苯酚（p-AP），表现出较高的催化性能，其表观速率常数为0.25 min^-1。Pt/MWCNTs多次使用后没有显著的活性损失，显示出了良好的稳定性。上述实验结果证明，除了传统的紫外光照射等手段以外，可见光照射也同样是制备铂金属催化剂非常有效的方法。而且，催化剂的形貌控制也完全可以通过简单而非复杂的实验条件加以实现。

Visible Light-Assisted Synthesis of Platinum Nanoparticles for Catalytic Reduction Reaction of p-Nitrophenol

Here, platinum nanoparticles were synthesized on multi-walled carbon nanotubes (MWCNTs) in one step under the irradiation of visible light without any extra additives except ethylene glycol (EG) as the reducing agent and stabilizer, and Pt/MWCNTs composites were successfully prepared. The catalytic performance of Pt/MWCNTs was studied in the reduction of p-nitrophenol (p-NP). The morphology and crystal structure of as-synthesized materials were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Visible light irradiation promotes the hydrolysis of aPtCl₄]^2- precursor in EG aqueous solution. By the electronic effect of the metal interface, the reduction of platinum precursors makes the formation of the uniformly dispersed Pt metal ultra-small particles with an average of 2.1 nm size. The as-prepared Pt/MWCNTs effectively catalyzed the reduction of p-NP to p-aminophenol (p-AP) with NaBH₄, exhibiting a high catalytic performance with an apparent rate constant of 0.25 min^-1. Furthermore, high reusability without significant activity loss presents that Pt/MWCNTs prepared can be an excellent and stable catalyst. The experimental results prove that besides traditional light irradiation methods, e.g. ultraviolet, the proper utilization of visible light is also a very effective method for preparing platinum metal catalysts and the morphology control can be achieved in some simple ways rather than complex reaction conditions.