کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9594706 | 1507985 | 2005 | 15 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Reactivity studies with gold-supported molybdenum nanoparticles
دانلود مقاله + سفارش ترجمه
دانلود مقاله ISI انگلیسی
رایگان برای ایرانیان
کلمات کلیدی
Clusters - خوشهChemical vapor deposition - رسوب بخار شیمیایی یا انباشت به روش تبخیر شیمیاییSurface structure, morphology, roughness, and topography - ساختار سطح، مورفولوژی، زبری و توپوگرافیSulfides - سولفید هاThermal desorption spectroscopy - طیف سنجی جذب حرارتیMolybdenum - مولیبدنومScanning tunneling microscopy - میکروسکوپ تونلی روبشی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
The reconstructed (22Â ÃÂ â3)-Au(1Â 1Â 1) surface was used as a template and inert support for depositing Mo nanoparticles for reactivity studies of desulfurization and the formation of MoSx nanoparticles. Nanoparticles of Mo were prepared on the Au(1Â 1Â 1) substrate by two methods: physical vapor deposition (PVD) of Mo and UV-assisted chemical vapor deposition (UV-CVD) through a molybdenum hexacarbonyl precursor. STM studies have shown that the Mo nanoparticles are thermodynamically unstable on the Au(1Â 1Â 1) surface, and that gold encapsulates Mo at temperatures above 300Â K. Reactivity studies using Auger electron spectroscopy (AES) and temperature programmed desorption (TPD) show that bare Mo nanoparticles are very reactive and can cause complete dissociation of hydrogen sulfide, methyl mercaptan, and thiophene. The presence of gold atoms on the Mo nanoparticles modifies their reactivity. In the case of H2S and CH3SH, the overall activity for desufurization is unaffected by gold encapsulation; however, the selectivity to form methane from CH3SH increased from 20% on bare Mo particles to 60% on gold-covered Mo particles. In contrast, gold-encapsulated Mo nanoparticles are relatively inert towards dissociation of thiophene. We believe that the interaction of R-SH compounds with Au-encapsulated Mo nanoparticles proceeds through intermediacy of surface gold thiolates.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Surface Science - Volume 574, Issues 2â3, 10 January 2005, Pages 244-258
Journal: Surface Science - Volume 574, Issues 2â3, 10 January 2005, Pages 244-258
نویسندگان
Denis V. Potapenko, Jillian M. Horn, Robert J. Beuhler, Zhen Song, Michael G. White,