The co-adsorption behaviors of SO2 and H2 O on face-centered cubic Cu（100） ideal surface were studied using the GGA-r PBE method of density functional theory（DFT） with slab models. The optimized structures of sing...The co-adsorption behaviors of SO2 and H2 O on face-centered cubic Cu（100） ideal surface were studied using the GGA-r PBE method of density functional theory（DFT） with slab models. The optimized structures of single H2 O and SO2 on Cu（100） surface were calculated at the coverage of 0.25 ML（molecular layer） and 0.5 ML. The results show that there was no obvious chemical adsorption of them on Cu（100） surface. The adsorbed structures, adsorption energy and electronic properties including difference charge density, valence charge density, Bader charge analysis and partial density of states（PDOS） of co-adsorbed structures of H2 O and SO2 were investigated to illustrate the interaction between adsorbates and surface. H2 O and SO2 can adsorb on surface of Cu atoms chemically via molecule form at the coverage of 0.25 ML, while H2 O dissociated into OH adsorbed on surface and H bonded with SO2 which keeps away from surface at the coverage of 0.5 ML.展开更多
The HCNH and CNH2 adsorption on different coordination sites of Cu（100） was theoretically studied considering the cluster approach. The present calculations show that the bridge site is the most favorite for CNH2 pe...The HCNH and CNH2 adsorption on different coordination sites of Cu（100） was theoretically studied considering the cluster approach. The present calculations show that the bridge site is the most favorite for CNH2 perpendicularly adsorbed on the Cu（100） surface via the C atom. For HCNH absorbed on the Cu（100） surface, the parallel adsorption mode with the C and N atoms nearly directly above the adjacent top sites of Cu（100） surface is the most favored. Both CNH2 and HCNH are strongly bound to the Cu（100） surface with CNH2 which is lightly stable （2.51 kJ·mol^-1）, indicating that both species may be co-adsorbed on the Cu（100） surface.展开更多
First-principles calculations based on density functional theory （DFr） and the generalized gradient approximation （GGA） have been used to study the adsorption of CO molecule on the Cu2O（111） oxygen-vacancy surfa...First-principles calculations based on density functional theory （DFr） and the generalized gradient approximation （GGA） have been used to study the adsorption of CO molecule on the Cu2O（111） oxygen-vacancy surface. Calculations indicate that the C-O bond is weakened upon adsorption compared with that over perfect surface. In addition, with the density increase of the defective sites, the adsorption energies of the defect-CO configuration increase whereas the C-O bond nearly remains constant.展开更多
The adsorptions of CO and 02 molecules individually on the stoichiometric Cu-terminatcd Cu20 （111） surface are investigated by first-principles calculations on the basis of the density functional theory. The calcula...The adsorptions of CO and 02 molecules individually on the stoichiometric Cu-terminatcd Cu20 （111） surface are investigated by first-principles calculations on the basis of the density functional theory. The calculated results indicate that the CO molecule preferably coordinates to the Cu2 site through its C atom with an adsorption energy of-1.69 eV, whereas the 02 molecule is most stably adsorbed in a tilt type with one O atom coordinating to the Cu2 site and the other O atom coordinating to the Cul site, and has an adsorption energy of -1.97 eV. From the analysis of density of states, it is observed that Cu 3d transfers electrons to 2π orbital of the CO molecule and the highest occupied 5σ orbital of the CO molecule transfers electrons to the substrate. The sharp band of Cu 4s is delocalized when compared to that before the CO molecule adsorption, and overlaps substantially with bands of the adsorbed CO molecule. There is a broadening of the 2π orbital of the 02 molecule because of its overlapping with the Cu 3d orbital, indicating that strong 3d-2π interactions are involved in the chemisorption of the 02 molecule on the surface.展开更多
H_(2)O吸附引起的二次电子发射增强是导致真空微波器件与设备异常放电的关键因素。为了研究H_(2)O吸附对金属表面二次电子发射特性的影响规律,该文考虑电子−H_(2)O分子碰撞的7种散射类型,采用Monte Carlo方法模拟电子−H_(2)O吸附分子的...H_(2)O吸附引起的二次电子发射增强是导致真空微波器件与设备异常放电的关键因素。为了研究H_(2)O吸附对金属表面二次电子发射特性的影响规律,该文考虑电子−H_(2)O分子碰撞的7种散射类型,采用Monte Carlo方法模拟电子−H_(2)O吸附分子的散射过程,同时考虑功函数变化对电子出射概率的影响,建立了一种H_(2)O吸附Cu表面的二次电子发射模型,统计二次电子的最终状态,并对二次电子发射系数(secondary electron yield,SEY)和二次电子能谱(secondary electron spectrum,SES)的变化规律进行分析。结果表明,H_(2)O吸附能够降低表面功函数,且产生更多电离电子,导致SEY增大;但当吸附厚度大于100 nm时,SEY不再继续增大,这是由于吸附层较厚时,电子无法进入Cu基底,仅在吸附层内散射。SES的谱峰随着吸附厚度的增加而增强,表明H_(2)O能够促使更多的低能电子出射,这是造成二次电子发射增强的重要因素。该文的模型为研究复杂表面状态的二次电子发射提供了可靠的分析方法,相关结果能够用于分析解释真空微波器件与设备放电形成机理,优化设备部件的设计参数。展开更多
To further improve the removal ability of layered double hydroxide(LDH) for iodide(I^-) anions from wastewater, we prepared hierarchically porous Cu5Mg10Al5-LDH and used as a matrix for in suit growth of Cu/Cu2O on it...To further improve the removal ability of layered double hydroxide(LDH) for iodide(I^-) anions from wastewater, we prepared hierarchically porous Cu5Mg10Al5-LDH and used as a matrix for in suit growth of Cu/Cu2O on its surface, forming Cu/Cu2O-LDH, which was characterized and applied as an adsorbent.Results displayed high I^-saturation uptake capability(137.8 mg/g) of Cu/Cu2O-LDH compared with Cu5Mg10Al5-LDH(26.4 mg/g) even thermal activated LDH(76.1 mg/g).Thermodynamic analysis showed that the reaction between I^-anions and Cu/Cu2O-LDH is a spontaneous and exothermic.Uptake kinetics analysis exhibited that adsorption equilibrium can be reached after 265 min.Additionally, the adsorbent showed satisfactory selectivity in the presence of competitive anions(e.g., SO4^2-), and could achieve good adsorption performance in a wide pH range of 3–8.A cooperative adsorption mechanism was proposed on the basis of the following two aspects:(1) ion exchange between iodide and interlayer anions;(2) the adsorption performance of Cu, Cu(Ⅱ) and Cu2O for I^-.Meanwhile, the difference between the adsorption mechanism of Cu/Cu2O-LDH, Cu5Mg10Al5-LDH and Cu5Mg10Al5-CLDH adsorbents was also elaborated and verified.展开更多
Nd2Cu2O4+δnanosheets were synthesized via coordination complex method(CCM)by using[NdCu(3,4-pdc)2(OAc)(H2O)5]·6.5H2O(1,3,4-pdc=3,4-pyridinedicarboxylic acid)as the precursor.Compared to the particles prepared by...Nd2Cu2O4+δnanosheets were synthesized via coordination complex method(CCM)by using[NdCu(3,4-pdc)2(OAc)(H2O)5]·6.5H2O(1,3,4-pdc=3,4-pyridinedicarboxylic acid)as the precursor.Compared to the particles prepared by SSM(simple solution method),Nd2Cu2O4+δprepared by CCM showed leaf-like morphology composed of nanosheets with an average thickness of 50~80 nm and a BET surface area up to 17.9 m^2/g.The Nd2Cu2O4+δsamples exhibit selective adsorption towards malachite green(MG)with significant Qm(maximum adsorption capacity)values reaching up 1.55 g/g at room temperature,and the thermodynamic parameters of adsorption process were obtained.In addition,the properties of selective adsorption of the prepared samples were investigated by temperature change tests.展开更多
基金Project(51222106)supported by the National Natural Science Foundation of ChinaProject(230201306500002)supported by the Fundamental Research Funds for the Central Universities+1 种基金ChinaProject(2014CB643300)supported by National Basic Research Program of China
文摘The co-adsorption behaviors of SO2 and H2 O on face-centered cubic Cu（100） ideal surface were studied using the GGA-r PBE method of density functional theory（DFT） with slab models. The optimized structures of single H2 O and SO2 on Cu（100） surface were calculated at the coverage of 0.25 ML（molecular layer） and 0.5 ML. The results show that there was no obvious chemical adsorption of them on Cu（100） surface. The adsorbed structures, adsorption energy and electronic properties including difference charge density, valence charge density, Bader charge analysis and partial density of states（PDOS） of co-adsorbed structures of H2 O and SO2 were investigated to illustrate the interaction between adsorbates and surface. H2 O and SO2 can adsorb on surface of Cu atoms chemically via molecule form at the coverage of 0.25 ML, while H2 O dissociated into OH adsorbed on surface and H bonded with SO2 which keeps away from surface at the coverage of 0.5 ML.
基金the National Natural Science Foundation of China(20673019,20773024)the Science Foundation of Fujian Province (2006J0256, Z0513005)the Funding of Fuzhou University(XRC-0732, 2008-XQ-07)
文摘The HCNH and CNH2 adsorption on different coordination sites of Cu（100） was theoretically studied considering the cluster approach. The present calculations show that the bridge site is the most favorite for CNH2 perpendicularly adsorbed on the Cu（100） surface via the C atom. For HCNH absorbed on the Cu（100） surface, the parallel adsorption mode with the C and N atoms nearly directly above the adjacent top sites of Cu（100） surface is the most favored. Both CNH2 and HCNH are strongly bound to the Cu（100） surface with CNH2 which is lightly stable （2.51 kJ·mol^-1）, indicating that both species may be co-adsorbed on the Cu（100） surface.
基金Supported by the National Natural Science Foundation of China (No. 10676007) and NCETFJ
文摘First-principles calculations based on density functional theory （DFr） and the generalized gradient approximation （GGA） have been used to study the adsorption of CO molecule on the Cu2O（111） oxygen-vacancy surface. Calculations indicate that the C-O bond is weakened upon adsorption compared with that over perfect surface. In addition, with the density increase of the defective sites, the adsorption energies of the defect-CO configuration increase whereas the C-O bond nearly remains constant.
基金Project supported by the National High Technology Research and Development Program of China (Grant No. 2009AA03 Z428)the National Natural Science Foundation of China (Grant No. 50872005)+1 种基金the National Basic Research Program of China (Grant No. 2007CB613306)the Innovation Foundation of BUAA for Ph. D. Graduates
文摘The adsorptions of CO and 02 molecules individually on the stoichiometric Cu-terminatcd Cu20 （111） surface are investigated by first-principles calculations on the basis of the density functional theory. The calculated results indicate that the CO molecule preferably coordinates to the Cu2 site through its C atom with an adsorption energy of-1.69 eV, whereas the 02 molecule is most stably adsorbed in a tilt type with one O atom coordinating to the Cu2 site and the other O atom coordinating to the Cul site, and has an adsorption energy of -1.97 eV. From the analysis of density of states, it is observed that Cu 3d transfers electrons to 2π orbital of the CO molecule and the highest occupied 5σ orbital of the CO molecule transfers electrons to the substrate. The sharp band of Cu 4s is delocalized when compared to that before the CO molecule adsorption, and overlaps substantially with bands of the adsorbed CO molecule. There is a broadening of the 2π orbital of the 02 molecule because of its overlapping with the Cu 3d orbital, indicating that strong 3d-2π interactions are involved in the chemisorption of the 02 molecule on the surface.
文摘H_(2)O吸附引起的二次电子发射增强是导致真空微波器件与设备异常放电的关键因素。为了研究H_(2)O吸附对金属表面二次电子发射特性的影响规律,该文考虑电子−H_(2)O分子碰撞的7种散射类型,采用Monte Carlo方法模拟电子−H_(2)O吸附分子的散射过程,同时考虑功函数变化对电子出射概率的影响,建立了一种H_(2)O吸附Cu表面的二次电子发射模型,统计二次电子的最终状态,并对二次电子发射系数(secondary electron yield,SEY)和二次电子能谱(secondary electron spectrum,SES)的变化规律进行分析。结果表明,H_(2)O吸附能够降低表面功函数,且产生更多电离电子,导致SEY增大;但当吸附厚度大于100 nm时,SEY不再继续增大,这是由于吸附层较厚时,电子无法进入Cu基底,仅在吸附层内散射。SES的谱峰随着吸附厚度的增加而增强,表明H_(2)O能够促使更多的低能电子出射,这是造成二次电子发射增强的重要因素。该文的模型为研究复杂表面状态的二次电子发射提供了可靠的分析方法,相关结果能够用于分析解释真空微波器件与设备放电形成机理,优化设备部件的设计参数。
基金supported by the National Natural Science Foundation of China(Nos.11805101 and 11205089)the Jiangsu Engineering Technology Research Center of Environmental Cleaning Materials(No.KFK1504)the Environmental Protection Research Project of Jiangsu Province(No.JSZC-D2018-044).
文摘To further improve the removal ability of layered double hydroxide(LDH) for iodide(I^-) anions from wastewater, we prepared hierarchically porous Cu5Mg10Al5-LDH and used as a matrix for in suit growth of Cu/Cu2O on its surface, forming Cu/Cu2O-LDH, which was characterized and applied as an adsorbent.Results displayed high I^-saturation uptake capability(137.8 mg/g) of Cu/Cu2O-LDH compared with Cu5Mg10Al5-LDH(26.4 mg/g) even thermal activated LDH(76.1 mg/g).Thermodynamic analysis showed that the reaction between I^-anions and Cu/Cu2O-LDH is a spontaneous and exothermic.Uptake kinetics analysis exhibited that adsorption equilibrium can be reached after 265 min.Additionally, the adsorbent showed satisfactory selectivity in the presence of competitive anions(e.g., SO4^2-), and could achieve good adsorption performance in a wide pH range of 3–8.A cooperative adsorption mechanism was proposed on the basis of the following two aspects:(1) ion exchange between iodide and interlayer anions;(2) the adsorption performance of Cu, Cu(Ⅱ) and Cu2O for I^-.Meanwhile, the difference between the adsorption mechanism of Cu/Cu2O-LDH, Cu5Mg10Al5-LDH and Cu5Mg10Al5-CLDH adsorbents was also elaborated and verified.
基金supported by Liaoning Province College Innovative Talents Fund Project(No.LCR2018016)the Natural Science Foundation of Liaoning Province(No.2019-MS-244)。
文摘Nd2Cu2O4+δnanosheets were synthesized via coordination complex method(CCM)by using[NdCu(3,4-pdc)2(OAc)(H2O)5]·6.5H2O(1,3,4-pdc=3,4-pyridinedicarboxylic acid)as the precursor.Compared to the particles prepared by SSM(simple solution method),Nd2Cu2O4+δprepared by CCM showed leaf-like morphology composed of nanosheets with an average thickness of 50~80 nm and a BET surface area up to 17.9 m^2/g.The Nd2Cu2O4+δsamples exhibit selective adsorption towards malachite green(MG)with significant Qm(maximum adsorption capacity)values reaching up 1.55 g/g at room temperature,and the thermodynamic parameters of adsorption process were obtained.In addition,the properties of selective adsorption of the prepared samples were investigated by temperature change tests.
