The first-principles calculations are performed to investigate the adsorption of O2 molecules on an Sn（lll） 2 × 2 surface. The chemisorbed adsorption precursor states for O2 are identified to be along the paral...The first-principles calculations are performed to investigate the adsorption of O2 molecules on an Sn（lll） 2 × 2 surface. The chemisorbed adsorption precursor states for O2 are identified to be along the parallel and vertical channels, and the surface reconstructions of Sn（111） induced by oxygen adsorption are studied. Based on this, the adsorption behaviours of O2 on X（111） （X=Si, Ge, Sn, Pb） surfaces are analysed, and the most stable adsorption channels of O2 on X（111） （X=Si, Ge, Sn, Pb） are identified. The surface reconstructions and electron distributions along the most stable adsorption channels are discussed and compared. The results show that the O2 adsorption ability declines gradually and the amount of charge transferred decreases with the enhancement of metallicity.展开更多
Using first-principles calculations, we systematically study the dissociations of 02 molecules on different ultrathin Pb（lll） films. According to our previous work revealing the molecular adsorption precursor states...Using first-principles calculations, we systematically study the dissociations of 02 molecules on different ultrathin Pb（lll） films. According to our previous work revealing the molecular adsorption precursor states for O2, we further explore why there are two nearly degenerate adsorption states on Pb（lll） ultrathin films, but no precursor adsorption states existing at all on Mg（0001） and Al（lll） surfaces. The reason is concluded to be the different surface electronic structures. For the O2 dissociation, we consider both the reaction channels from gas-like and molecularly adsorbed O2 molecules. We find that the energy barrier for O2 dissociation from the molecular adsorption precursor states is always smaller than that from O2 gas. The most energetically favorable dissociation process is found to be the same on different Pb（lll） fihns, and the energy barriers are found to be influenced by the quantum size effects of Pb（lll） films.展开更多
Using comprehensive density functional theory calculations, we systematically investigate the structure, stability, and electronic properties of five polymorphs of GeSe monolayer, and highlight the differences in thei...Using comprehensive density functional theory calculations, we systematically investigate the structure, stability, and electronic properties of five polymorphs of GeSe monolayer, and highlight the differences in their structural and electronic properties. Our calculations show that the five free-standing polymorphs of Ge Se are stable semiconductors. β-GeSe, γ-GeSe, δ-GeSe, and ε-GeSe are indirect gap semiconductors, whereas α-GeSe is a direct gap semiconductor. We calculated Raman spectra and scanning tunneling microscopy images for the five polymorphs. Our results show that the β-GeSe monolaye r is a candidate for water splitting.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.51102009)the Fundamental Research Funds for the Central Universities,China(Grant No.JD1109)
文摘The first-principles calculations are performed to investigate the adsorption of O2 molecules on an Sn（lll） 2 × 2 surface. The chemisorbed adsorption precursor states for O2 are identified to be along the parallel and vertical channels, and the surface reconstructions of Sn（111） induced by oxygen adsorption are studied. Based on this, the adsorption behaviours of O2 on X（111） （X=Si, Ge, Sn, Pb） surfaces are analysed, and the most stable adsorption channels of O2 on X（111） （X=Si, Ge, Sn, Pb） are identified. The surface reconstructions and electron distributions along the most stable adsorption channels are discussed and compared. The results show that the O2 adsorption ability declines gradually and the amount of charge transferred decreases with the enhancement of metallicity.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.90921003,10904004 and 60776063)the Fundamental Research Funds for the Central Universities,China(Grant No.JD1109)
文摘Using first-principles calculations, we systematically study the dissociations of 02 molecules on different ultrathin Pb（lll） films. According to our previous work revealing the molecular adsorption precursor states for O2, we further explore why there are two nearly degenerate adsorption states on Pb（lll） ultrathin films, but no precursor adsorption states existing at all on Mg（0001） and Al（lll） surfaces. The reason is concluded to be the different surface electronic structures. For the O2 dissociation, we consider both the reaction channels from gas-like and molecularly adsorbed O2 molecules. We find that the energy barrier for O2 dissociation from the molecular adsorption precursor states is always smaller than that from O2 gas. The most energetically favorable dissociation process is found to be the same on different Pb（lll） fihns, and the energy barriers are found to be influenced by the quantum size effects of Pb（lll） films.
基金supported by the National Basic Research Program of China (2014CB931700)the National Natural Science Foundation of China (61222403 and 21403109)+1 种基金the Natural Science Foundation of Jiangsu province (BK20140769)the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘Using comprehensive density functional theory calculations, we systematically investigate the structure, stability, and electronic properties of five polymorphs of GeSe monolayer, and highlight the differences in their structural and electronic properties. Our calculations show that the five free-standing polymorphs of Ge Se are stable semiconductors. β-GeSe, γ-GeSe, δ-GeSe, and ε-GeSe are indirect gap semiconductors, whereas α-GeSe is a direct gap semiconductor. We calculated Raman spectra and scanning tunneling microscopy images for the five polymorphs. Our results show that the β-GeSe monolaye r is a candidate for water splitting.
