An ab initio molecular orbital study connected with adsorption experiments was performed to determine the mechanism of physical adsorption and chemical adsorption of C 2H 4 on metals, and to compare the effects of the...An ab initio molecular orbital study connected with adsorption experiments was performed to determine the mechanism of physical adsorption and chemical adsorption of C 2H 4 on metals, and to compare the effects of the two kinds of adsorption.The results indicated that the adsorption styles were determined by whether there were local symmetry-adapted orbitals, whether the energy gap between symmetry-adapted orbitals was small and whether the electron occupancy of the symmetry-adapted orbitals was “occupancy vs. vacancy”.The different valence shells and orbital energies of Ag + and Na + resulted in different adsorption styles,chemical adsorption of C 2H 4 on Ag + and physical adsorption of C 2H 4 on Na + respectively.展开更多
XPS has been applied to study the reduction influence of the passivated Mo2N sample on H2 chemisorption at room temperature. It is found that most of the Mo6+ species was reduced to low valence molybdenum species (Mo...XPS has been applied to study the reduction influence of the passivated Mo2N sample on H2 chemisorption at room temperature. It is found that most of the Mo6+ species was reduced to low valence molybdenum species (Moδ+:δ■4) when reduc tion temperature was raised up to 673K, meanwhile sharp increases of both the irreversible and reversible hydrogen uptakes were measured. The irreversible amount increased to a larger extent. Accordingly, the active sites towards hydrogen adsorption are tentatively proposed to the low valence molybdenum species with nitrogen deficient.展开更多
文摘An ab initio molecular orbital study connected with adsorption experiments was performed to determine the mechanism of physical adsorption and chemical adsorption of C 2H 4 on metals, and to compare the effects of the two kinds of adsorption.The results indicated that the adsorption styles were determined by whether there were local symmetry-adapted orbitals, whether the energy gap between symmetry-adapted orbitals was small and whether the electron occupancy of the symmetry-adapted orbitals was “occupancy vs. vacancy”.The different valence shells and orbital energies of Ag + and Na + resulted in different adsorption styles,chemical adsorption of C 2H 4 on Ag + and physical adsorption of C 2H 4 on Na + respectively.
文摘XPS has been applied to study the reduction influence of the passivated Mo2N sample on H2 chemisorption at room temperature. It is found that most of the Mo6+ species was reduced to low valence molybdenum species (Moδ+:δ■4) when reduc tion temperature was raised up to 673K, meanwhile sharp increases of both the irreversible and reversible hydrogen uptakes were measured. The irreversible amount increased to a larger extent. Accordingly, the active sites towards hydrogen adsorption are tentatively proposed to the low valence molybdenum species with nitrogen deficient.
