表面处理对Pt/Al2O3光催化氧化NO的影响

Research of Surface Treatment on the Photocatalytic NO Oxidation Performance over Pt/Al2O3

以氯铂酸为Pt源,采用浸渍法制备了Pt/Al2O3复合光催化剂,并将其应用于光催化氧化NO。使用X射线衍射仪(XRD)、傅里叶红外光谱(FT-IR)、透射电镜(TEM)、扫描电镜(SEM)和紫外-可见光吸收光谱(UV-vis)研究了H2还原处理前后的Pt/Al2O3的形貌、结构以及光学性质。探究了NO氧化过程中,Pt/Al2O3复合体中Pt的价态以及表面羟基对光催化性能的影响。实验结果表明:Pt/Al2O3的形貌与结构在还原前后并无明显变化,但表面的羟基含量减少,导致产生的羟基自由基减少;此外,退火处理使得Pt/Al2O3中的离子态Pt被还原为金属态的Pt0,导致退火后Pt/Al2O3光催化氧化NO性能下降。

Pt/Al2O3 nano-photocatalyst was prepared by impregnation method using chloroplatinic acid as Pt source, and applied to the photocatalytic oxidation of NO. The morphology, structure and optical properties of Pt/Al2O3 with and without treated by H2 reduction annealing were researched by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and ultraviolet-visible absorption spectroscopy (UV-vis). Effect of the surface hydroxyl and the value of Pt over Pt/Al2O3 on the photocatalytic properties of the samples during NO oxidation was investigated. The experimental results showed that the morphology and structure of the annealed Pt/Al2O3 have no obvious change compared with those of the un-annealed treated samples, but the hydroxyl content on the surface decreased significantly, which resulted in less generation of hydroxyl radicals. Furthermore, the valence of Pt decreased after annealing treatment, which was not benefit for NO photocatalytic oxidation. These results led to the decreased photocatalytic activity of annealed Pt/Al2O3 for photocatalytic NO oxidation.