The chemisorption and direct decomposition of NO on Rh（100） and Rh（111） surfaces were studied by the density functional theory（DFT） with Dmol3 program.The calculation results show that for the Rh（100）surface,t...The chemisorption and direct decomposition of NO on Rh（100） and Rh（111） surfaces were studied by the density functional theory（DFT） with Dmol3 program.The calculation results show that for the Rh（100）surface,the bridge sites are found to be the preferred adsorption site,but for the Rh（111） surface,the three fold hollow（hcp） sites are found to be the most stable one;the transition states were confirmed for the direct decomposition of NO on Rh（100） and Rh（111） surfaces by successful transition state search,and the activation energy are 161.91 kJ/mol for Rh（100） and 183.72 kJ/mol for Rh（111）,respectively.展开更多
Intercalation of metal atoms into the interface of graphene and its supporting substrate has become an intriguing topic for the sake of weakening the interface coupling and constructing metal atomic layers under inert...Intercalation of metal atoms into the interface of graphene and its supporting substrate has become an intriguing topic for the sake of weakening the interface coupling and constructing metal atomic layers under inert covers. However, this novel behavior has rarely been reported on the analogous hexagonal boron nitride （h-BN） synthesized on metal substrates. Here, we describe a comparative study of Mn intercalation into the interfaces of graphene/Rh（111） and h-BN/Rh（111）, by using atomically-resolved scanning tunneling microscopy （STM） and density functional theory （DFT） calculations. The intercalation was performed by annealing as-deposited Mn clusters, and the starting temperature of Mn intercalation into h-BN/Rh（111） was found to be ~80 ~C higher than that for graphene/Rh（111）. Moreover, the intercalated islands of h-BN/Mn/Rh（111） usually possess more irregular shapes than those of graphene/Mn/Rh（111）, as illustrated by temperature-dependent STM observations. All these experimental facts suggest a stronger interaction of Mn with h-BN/Rh（111） than that with graphene/Rh（111）.展开更多
Density functional theory calculations within the generalized gradient approximation(GGA) have been carried out to study the structural and vibrational properties of carbon monoxide adsorption on Rh(111) surface. The ...Density functional theory calculations within the generalized gradient approximation(GGA) have been carried out to study the structural and vibrational properties of carbon monoxide adsorption on Rh(111) surface. The optimized geometries, adsorption energies and vibrationalfrequencies have been obtained and the preferred binding sites have been determined. Theresults show that at low coverage CO prefers to adsorb at top site and at high coverage one molecule occupies top site while the two other molecules occupy hcp and fcc hollow sitesrespectively. The investigation of the vibrational properties of CO chemisorption on Rh(111) shows that the top C-O stretching frequency increases along with the increase of the coverage. The site assignments, optimized geometries and calculated vibrational frequencies are found to be in good agreement with the experimental results.展开更多
Adsorption behaviors of 2-bromothiophene on the Rh（111） surface were discussed with DFT. The results revealed that adsorption at the parallel hol site and bridge site was the most stable. After adsorption, bond leng...Adsorption behaviors of 2-bromothiophene on the Rh（111） surface were discussed with DFT. The results revealed that adsorption at the parallel hol site and bridge site was the most stable. After adsorption, bond length of 2-bromothiophene changed significantly. Molecular plane was distorted, and C-H （Br, S） in the molecule was oblique and upswept against the metal surface. Vertical adsorption site was less stable than the plane adsorption site, but there was no distortion for the thiophene ring after adsorption. Aromaticity of 2-bromothiophene was destroyed at the hol and bridge adsorption sites, and the carbon atom in the thiophene ring presented quasi-sp3 hybfidizaton. After adsorption at the parallel hol, 2-bromothiophene obtained 0.86 electrons in total, and Rh（111） surface lost 2.08 electrons in all.展开更多
文摘The chemisorption and direct decomposition of NO on Rh（100） and Rh（111） surfaces were studied by the density functional theory（DFT） with Dmol3 program.The calculation results show that for the Rh（100）surface,the bridge sites are found to be the preferred adsorption site,but for the Rh（111） surface,the three fold hollow（hcp） sites are found to be the most stable one;the transition states were confirmed for the direct decomposition of NO on Rh（100） and Rh（111） surfaces by successful transition state search,and the activation energy are 161.91 kJ/mol for Rh（100） and 183.72 kJ/mol for Rh（111）,respectively.
基金This work was financially supported by the National Natural Science Foundation of China （Grant Nos. 51222201, 51290272, 51121091, and 21073003）, and the Ministry of Science and Technology of China （Grant Nos. 2012CB921404, 2011CB921903, 2011CB933003, and 2012CB933404）.
文摘Intercalation of metal atoms into the interface of graphene and its supporting substrate has become an intriguing topic for the sake of weakening the interface coupling and constructing metal atomic layers under inert covers. However, this novel behavior has rarely been reported on the analogous hexagonal boron nitride （h-BN） synthesized on metal substrates. Here, we describe a comparative study of Mn intercalation into the interfaces of graphene/Rh（111） and h-BN/Rh（111）, by using atomically-resolved scanning tunneling microscopy （STM） and density functional theory （DFT） calculations. The intercalation was performed by annealing as-deposited Mn clusters, and the starting temperature of Mn intercalation into h-BN/Rh（111） was found to be ~80 ~C higher than that for graphene/Rh（111）. Moreover, the intercalated islands of h-BN/Mn/Rh（111） usually possess more irregular shapes than those of graphene/Mn/Rh（111）, as illustrated by temperature-dependent STM observations. All these experimental facts suggest a stronger interaction of Mn with h-BN/Rh（111） than that with graphene/Rh（111）.
基金This work was supported by the National Natural Science Foundation of China(Grant No.20173036)the Special Doctoral Research Foundation of the Ministryof Education+1 种基金the Teaching and Research Award Program for Outstanding Young Teachers in Higher Education Institutions of the Ministry of Educationthe Start-Up Founding of Nanjing University.
文摘Density functional theory calculations within the generalized gradient approximation(GGA) have been carried out to study the structural and vibrational properties of carbon monoxide adsorption on Rh(111) surface. The optimized geometries, adsorption energies and vibrationalfrequencies have been obtained and the preferred binding sites have been determined. Theresults show that at low coverage CO prefers to adsorb at top site and at high coverage one molecule occupies top site while the two other molecules occupy hcp and fcc hollow sitesrespectively. The investigation of the vibrational properties of CO chemisorption on Rh(111) shows that the top C-O stretching frequency increases along with the increase of the coverage. The site assignments, optimized geometries and calculated vibrational frequencies are found to be in good agreement with the experimental results.
基金Supported by the National Natural Science Foundation of China(No.20273013)the Natural Science Foundation of Fujian Province(No.2002F010)the State Key Laboratory of Structural Chemistry(20090060)
文摘Adsorption behaviors of 2-bromothiophene on the Rh（111） surface were discussed with DFT. The results revealed that adsorption at the parallel hol site and bridge site was the most stable. After adsorption, bond length of 2-bromothiophene changed significantly. Molecular plane was distorted, and C-H （Br, S） in the molecule was oblique and upswept against the metal surface. Vertical adsorption site was less stable than the plane adsorption site, but there was no distortion for the thiophene ring after adsorption. Aromaticity of 2-bromothiophene was destroyed at the hol and bridge adsorption sites, and the carbon atom in the thiophene ring presented quasi-sp3 hybfidizaton. After adsorption at the parallel hol, 2-bromothiophene obtained 0.86 electrons in total, and Rh（111） surface lost 2.08 electrons in all.
