Wu Qiang, Gao Hongwei, He Hong
State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
J Phys Chem B. 2006 Apr 27;110(16):8320-4. doi: 10.1021/jp060105+.
The formation and configuration of sulfate species on Ag/Al2O3 were studied by means of in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and density functional theory (DFT) calculations. The comparison between theoretical and experimental vibration spectra enable us to draw the following conclusions: Bidentate sulfate species rather than tridentate sulfate species are the predominant surface species on Ag/Al2O3. Moreover, both bidentate and tridentate sulfate species may coexist on the catalyst surface at a lower coverage. The accumulation of surface sulfate species could well explain the blue shift of the sulfate species in IR spectra. In addition, the in situ DRIFTS could distinguish between the sulfate species that linked to Al site and Ag site, which was well supported by temperature-programmed desorption (TPD) results.
通过原位漫反射红外傅里叶变换光谱（DRIFTS）和密度泛函理论（DFT）计算研究了Ag/Al2O3上硫酸根物种的形成和构型。理论振动光谱与实验振动光谱的比较使我们能够得出以下结论：双齿硫酸根物种而非三齿硫酸根物种是Ag/Al2O3上的主要表面物种。此外，在较低覆盖率下，双齿和三齿硫酸根物种可能共存于催化剂表面。表面硫酸根物种的积累可以很好地解释红外光谱中硫酸根物种的蓝移。此外，原位DRIFTS可以区分与铝位点和银位点相连的硫酸根物种，程序升温脱附（TPD）结果很好地支持了这一点。
