کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5425472 1395857 2006 14 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Adsorption of cyclohexadiene, cyclohexene and cyclohexane on Pt(1 1 1)
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
Adsorption of cyclohexadiene, cyclohexene and cyclohexane on Pt(1 1 1)
چکیده انگلیسی

The adsorption of 1,3-cyclohexadiene, 1,4-cyclohexadiene, cyclohexene and cyclohexane on Pt(1 1 1) was studied using ab initio density functional theory. For 1,3-cyclohexadiene three adsorption modes were distinguished: bridge 1,2-di-σ/3,4-π, hollow 1,4-di-σ/2,3-π and bridge 1,4-di-σ/2,3-π with adsorption energies of −155, −147 and −75 kJ/mol, respectively. Three stable adsorption modes were also identified for 1,4-cyclohexadiene: bridge quadra-σ, hollow di-σ/π and bridge di-π with adsorption energies of −146 kJ/mol, −142 kJ/mol and −88 kJ/mol, respectively. Cyclohexene was found to adsorb in six modes: 4 di-σ and 2 π-adsorption modes. The preferred configuration was found to be boat di-σ with an adsorption energy of −81 kJ/mol. The three other di-σ adsorption modes have comparable adsorption energies, ranging from −64 to −69 kJ/mol. Molecular strain and CPt bonding energies are used to elucidate stability trends. Cyclohexane is found to adsorb only at the hollow site whereby the axial hydrogen atoms are positioned over surface Pt-atoms with an adsorption energy of −37 kJ/mol. The calculations correctly predict the weakening of the axial CH bonds and provide a possible explanation for the large shift in the vibrational frequencies.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Surface Science - Volume 600, Issue 16, 15 August 2006, Pages 3121-3134
نویسندگان
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