Cyclohexane is a high-valued chemical receivingsignificant interest in liquid hydrogen storage technology.TiO_(2)-based catalysts show high performance in the photocatalytic dehydrogenation of cyclohexane under mild c...Cyclohexane is a high-valued chemical receivingsignificant interest in liquid hydrogen storage technology.TiO_(2)-based catalysts show high performance in the photocatalytic dehydrogenation of cyclohexane under mild conditions,but the detailed reaction mechanism is not well understood.With the surface science approaches,we have studied the adsorption and surface chemistry of cyclohexane on rutile TiO_(2)(110).The thermal desorption spectroscopy and X-ray photoelectron spectroscopy results both demonstrate the molecular adsorption of cyclohexane on rutile TiO_(2)(110).Upon the UV Hg light irradiation,photodesorption of cyclohexane occurs from both the chemisorbed monolayer and the multilayer.No decomposition nor dehydrogenation of cyclohexane occurs on rutile TiO_(2)(110).These results deepen the fundamental understanding of the surface chemistry of cyclohexane on the TiO_(2)surface.展开更多
The structural and electronic properties of TiC（110） surfaces are calculated using the first-principles total-energy plane-wave pseudopotential method based on density functional theory. The calculated results of st...The structural and electronic properties of TiC（110） surfaces are calculated using the first-principles total-energy plane-wave pseudopotential method based on density functional theory. The calculated results of structural relaxation and surface energy for TiC（110） slab indicate that slab with 7 layers shows bulk-like characteristic interiors, and the changes of slab occur on the outmost three layers, which shows that the relaxation only influences the top three layers. Meanwhile, the strong Ti—C covalent bonding can be found in the distribution of charge density on the （100） plane. The interlayer Ti—C chemical bonds are reinforced and the outermost interlayer distance is reduced as a result of the charge depletion in the vacuum and the charge accumulations in the interlayer region between the first and second layers. The surface energy of TiC（110） is calculated to be 3.53 J/m2.展开更多
Photocatalytic degradation of gaseous pollutants on Bi-based semiconductors under solar lightirradiation has attracted significant attention.However,their application in gaseous straight-chainalkane purification is st...Photocatalytic degradation of gaseous pollutants on Bi-based semiconductors under solar lightirradiation has attracted significant attention.However,their application in gaseous straight-chainalkane purification is still rare.Here,a series of Bi/BiOBr composites were solvothermally synthe-sized and applied in solar-light-driven photocatalytic degradation of gaseous n-hexane.The charac-terization results revealed that both increasing number of functional groups of alcohol solvent(from methanol and ethylene glycol to glycerol)and solvothermal temperature(from 160 and 180to 200℃)facilitated the in-situ formation of metallic Bi nanospheres on BiOBr nanoplates withexposed(110)facets.Meanwhile,chemical bonding between Bi and BiOBr was observed on theseexposed facets that resulted in the formation of surface oxygen vacancy.Furthermore,the synergis-tic effect of optimum surface oxygen vacancy on exposed(110)facets led to a high visible light re-sponse,narrow band gap,great photocurrent,low recombination rate of the charge carriers,andstrong·O2-and h*formation,all of which resulted in the highest removal efficiency of 97.4%within120 min of 15 ppmv of n-hexane on Bi/BiOBr.Our findings efficiently broaden the application ofBi-based photocatalysis technology in the purification of gaseous straight-chain pollutants emittedby the petrochemical industry.展开更多
MgH2 is a promising and popular hydrogen storage material.In this work,the hydrogen desorption reactions of a single Pd atom adsorbed MgH2(110)surface are investigated by using first-principles density functional theo...MgH2 is a promising and popular hydrogen storage material.In this work,the hydrogen desorption reactions of a single Pd atom adsorbed MgH2(110)surface are investigated by using first-principles density functional theory calculations.We find that a single Pd atom adsorbed on the MgH2(110)surface can significantly lower the energy barrier of the hydrogen desorption reactions from 1.802 eV for pure MgH2(110)surface to 1.154 eV for Pd adsorbed MgH2(110)surface,indicating a strong Pd single-atom catalytic effect on the hydrogen desorption reactions.Furthermore,the Pd single-atom catalysis significantly reduces the hydrogen desorption temperature from 573K to 367K,which makes the hydrogen desorption reactions occur more easily and quickly on the MgH2(110)surface.We also discuss the microscopic process of the hydrogen desorption reactions through the reverse process of hydrogen spillover mechanism on the MgH2(110)surface.This study shows that Pd/MgH2 thin films can be used as good hydrogen storage materials in future experiments.展开更多
The interaction of reactants with catalysts has always been an important subject for catalytic reactions.As a promising catalyst with versatile applications,titania has been intensively studied for decades.In this wor...The interaction of reactants with catalysts has always been an important subject for catalytic reactions.As a promising catalyst with versatile applications,titania has been intensively studied for decades.In this work we have investigated the role of bridge bonded oxygen vacancy(O_(v))in methyl groups and carbon monoxide(CO)adsorption on rutile TiO_(2)(110)(R-TiO_(2)(110))with the temperature programmed desorption technique.The results show a clear different tendency of the desorption of methyl groups adsorbed on bridge bonded oxygen(O_(b)),and CO molecules on the five coordinate Ti^(4+)sites(Ti_(5c))as the Ovconcentration changes,suggesting that the surface defects may have crucial influence on the absorption of species on different sites of R-TiO_(2)(110).展开更多
基金supported by the National Natural Science Foundation of China (90922022)Natural Science Foundation of Fujian Province,China(2012101032,2012101041)Foundation of State Key Laboratory of Coal Combustion of Huazhong University of Science and Technology,China (FSKLCC1110)~~
基金This work is supported by the National Natural Science Foundation of China(No.22202191).
文摘Cyclohexane is a high-valued chemical receivingsignificant interest in liquid hydrogen storage technology.TiO_(2)-based catalysts show high performance in the photocatalytic dehydrogenation of cyclohexane under mild conditions,but the detailed reaction mechanism is not well understood.With the surface science approaches,we have studied the adsorption and surface chemistry of cyclohexane on rutile TiO_(2)(110).The thermal desorption spectroscopy and X-ray photoelectron spectroscopy results both demonstrate the molecular adsorption of cyclohexane on rutile TiO_(2)(110).Upon the UV Hg light irradiation,photodesorption of cyclohexane occurs from both the chemisorbed monolayer and the multilayer.No decomposition nor dehydrogenation of cyclohexane occurs on rutile TiO_(2)(110).These results deepen the fundamental understanding of the surface chemistry of cyclohexane on the TiO_(2)surface.
基金Project (200902554) supported by National Post-doctor Foundation, ChinaProject (200802015) supported by the Post-Doctor Foundation of Shandong Province, China
文摘The structural and electronic properties of TiC（110） surfaces are calculated using the first-principles total-energy plane-wave pseudopotential method based on density functional theory. The calculated results of structural relaxation and surface energy for TiC（110） slab indicate that slab with 7 layers shows bulk-like characteristic interiors, and the changes of slab occur on the outmost three layers, which shows that the relaxation only influences the top three layers. Meanwhile, the strong Ti—C covalent bonding can be found in the distribution of charge density on the （100） plane. The interlayer Ti—C chemical bonds are reinforced and the outermost interlayer distance is reduced as a result of the charge depletion in the vacuum and the charge accumulations in the interlayer region between the first and second layers. The surface energy of TiC（110） is calculated to be 3.53 J/m2.
文摘Photocatalytic degradation of gaseous pollutants on Bi-based semiconductors under solar lightirradiation has attracted significant attention.However,their application in gaseous straight-chainalkane purification is still rare.Here,a series of Bi/BiOBr composites were solvothermally synthe-sized and applied in solar-light-driven photocatalytic degradation of gaseous n-hexane.The charac-terization results revealed that both increasing number of functional groups of alcohol solvent(from methanol and ethylene glycol to glycerol)and solvothermal temperature(from 160 and 180to 200℃)facilitated the in-situ formation of metallic Bi nanospheres on BiOBr nanoplates withexposed(110)facets.Meanwhile,chemical bonding between Bi and BiOBr was observed on theseexposed facets that resulted in the formation of surface oxygen vacancy.Furthermore,the synergis-tic effect of optimum surface oxygen vacancy on exposed(110)facets led to a high visible light re-sponse,narrow band gap,great photocurrent,low recombination rate of the charge carriers,andstrong·O2-and h*formation,all of which resulted in the highest removal efficiency of 97.4%within120 min of 15 ppmv of n-hexane on Bi/BiOBr.Our findings efficiently broaden the application ofBi-based photocatalysis technology in the purification of gaseous straight-chain pollutants emittedby the petrochemical industry.
基金supported by the National Key Basic Research Program(No.2011CB921404)National Natural Science Foundation of China(No.21421063,No.91021004,No.21233007,No.21803066)+2 种基金Strategic Priority Research Program of Chinese Academy of Sciences(No.XDC01000000)Research Start-Up Grants(No.KY2340000094)from University of Science and Technology of Chinathe Chinese Academy of Sciences Pioneer Hundred Talents Program
文摘MgH2 is a promising and popular hydrogen storage material.In this work,the hydrogen desorption reactions of a single Pd atom adsorbed MgH2(110)surface are investigated by using first-principles density functional theory calculations.We find that a single Pd atom adsorbed on the MgH2(110)surface can significantly lower the energy barrier of the hydrogen desorption reactions from 1.802 eV for pure MgH2(110)surface to 1.154 eV for Pd adsorbed MgH2(110)surface,indicating a strong Pd single-atom catalytic effect on the hydrogen desorption reactions.Furthermore,the Pd single-atom catalysis significantly reduces the hydrogen desorption temperature from 573K to 367K,which makes the hydrogen desorption reactions occur more easily and quickly on the MgH2(110)surface.We also discuss the microscopic process of the hydrogen desorption reactions through the reverse process of hydrogen spillover mechanism on the MgH2(110)surface.This study shows that Pd/MgH2 thin films can be used as good hydrogen storage materials in future experiments.
基金supported by the National Natural Science Foundation of China (No.21973084 and No.21803056)。
文摘The interaction of reactants with catalysts has always been an important subject for catalytic reactions.As a promising catalyst with versatile applications,titania has been intensively studied for decades.In this work we have investigated the role of bridge bonded oxygen vacancy(O_(v))in methyl groups and carbon monoxide(CO)adsorption on rutile TiO_(2)(110)(R-TiO_(2)(110))with the temperature programmed desorption technique.The results show a clear different tendency of the desorption of methyl groups adsorbed on bridge bonded oxygen(O_(b)),and CO molecules on the five coordinate Ti^(4+)sites(Ti_(5c))as the Ovconcentration changes,suggesting that the surface defects may have crucial influence on the absorption of species on different sites of R-TiO_(2)(110).
