کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5362648 | 1388291 | 2010 | 6 صفحه PDF | دانلود رایگان |
We studied computationally the relative stability of PtML/WC(0Â 0Â 0Â 1) [pseudomorphic monolayer of Pt(1Â 1Â 1) on WC(0Â 0Â 0Â 1)] interfacial structures using a density functional slab model approach. The work of adhesion was calculated for six different interfacial structures, taking into account both W- and C-terminations of the carbide. The results show that the optimal interfacial structure of PtML/WC(0Â 0Â 0Â 1) is the W-terminated WC(0Â 0Â 0Â 1) with Pt atoms adhesion on the hcp site (W-hcp). The nature of metal/carbide bonding for the W-hcp interfacial geometry was determined on the basis of the partial density of states (PDOS). Adsorption of atomic hydrogen and dissociation of the hydrogen molecule on the W-hcp PtML/WC(0Â 0Â 0Â 1) was investigated and compared to that on Pt(1Â 1Â 1). It is found that the most favorable H2 dissociation channels need similar activation energies of 5.28 and 4.93Â kJ/mol on PtML/WC(0Â 0Â 0Â 1) and Pt(1Â 1Â 1), respectively, with the release of considerable reaction energies. Furthermore, adsorption of CO on the W-hcp PtML/WC(0Â 0Â 0Â 1) and Pt(1Â 1Â 1) was also investigated. The results indicate that PtML/WC(0Â 0Â 0Â 1) is much less susceptible to CO poisoning than Pt(1Â 1Â 1), especially at the low coverage of CO.
Journal: Applied Surface Science - Volume 256, Issue 24, 1 October 2010, Pages 7400-7405