为制备具有高催化活性的纳米多孔Ni基合金电极用于碱性电解水产氢,首先制备了Ni、NiCo、NiCu和NiFe 4种Ni基合金条带;基于NiCu和NiCo合金体系,利用脱合金化法制备了纳米多孔NiCu和NiCo合金;采用XRD、BET、TEM、LSV等方法分析Ni基合金的...为制备具有高催化活性的纳米多孔Ni基合金电极用于碱性电解水产氢,首先制备了Ni、NiCo、NiCu和NiFe 4种Ni基合金条带;基于NiCu和NiCo合金体系,利用脱合金化法制备了纳米多孔NiCu和NiCo合金;采用XRD、BET、TEM、LSV等方法分析Ni基合金的晶体结构、形貌结构和电化学性能.结果表明:Ni基合金均为面心立方晶型的单相固溶体;纳米多孔NiCo合金具有均匀的多孔结构,孔径分布为3~6 nm;与原Ni基合金相比,纳米多孔NiCu和NiCo合金的过电势和塔菲尔(Tafel)斜率大幅降低,催化活性明显提高,纳米多孔NiCo合金在电流密度20 m A/cm^2下过电势为140 m V,Tafel斜率为60 m V/dec),接近于Pt.因此,选择具有协同作用的掺杂元素和构建纳米多孔结构是提高Ni基合金电极产氢反应催化活性的有效途径.展开更多
A thermal nitridation route for the assembly and polymerization of molecular triazine units to heptazine-based covalent frameworks has been successfully established. The obtained conjugated carbon nitride polymers fea...A thermal nitridation route for the assembly and polymerization of molecular triazine units to heptazine-based covalent frameworks has been successfully established. The obtained conjugated carbon nitride polymers feature nanostructures that show enhanced photocatalytic reactivity for hydrogen production under visible light irradiation.展开更多
Molybdenum sulfides are promising electrocatalysts for the hydrogen evolution reaction(HER).Sand Mo‐related species have been proposed as the active site for forming adsorbed hydrogen to initiate the HER;however,the ...Molybdenum sulfides are promising electrocatalysts for the hydrogen evolution reaction(HER).Sand Mo‐related species have been proposed as the active site for forming adsorbed hydrogen to initiate the HER;however,the nature of the interaction between Mo centers and S ligands is unclear.Further,the development of cost‐effective water‐splitting systems using neutral water as a proton source for H2evolution is highly desirable,whereas the mechanism of the HER at neutral pH is rarely discussed.Here,the structural change in the Mo?Mo and S?S species in a synthesized molybdenum sulfide was monitored at neutral pH using in situ electrochemical Raman spectroscopy.Analysis of the potential dependent Raman spectra revealed that the band assigned to a terminal S?S species emerged along with synchronized changes in the frequency of the Mo?Mo,Mo3?μ3S,and Mo?S vibrational bands.This indicates that Mo?Mo bonds and terminal S?S ligands play synergistic roles in facilitating hydrogen evolution,likely via the internal reorganization of trinuclear Mo3?thio species.The nature and role of metal‐ligand interactions in the HER revealed in this study demonstrated a mechanism that is distinct from those reported previously in which the S or Mo sites function independently.展开更多
An efficient CuO‐modified zeolitic imidazolate framework‐9(ZIF‐9)photocatalyst is successfully prepared at room temperature under mild conditions.It is observed that the ZIF‐9/CuO photocatalyst is effective for H2...An efficient CuO‐modified zeolitic imidazolate framework‐9(ZIF‐9)photocatalyst is successfully prepared at room temperature under mild conditions.It is observed that the ZIF‐9/CuO photocatalyst is effective for H2generation under visible light with sacrificial agent conditions.When the CuO is introduced,the photocatalytic properties of ZIF‐9are greatly improved and when the content of CuO is40%,the photocatalytic activity reaches a maximum of78.74μmol after5h.This results from the200–300nm cube structure of ZIF‐9being able to adsorb more dye molecules and the CuO,which connects with ZIF‐9,greatly improving the electronic transmission efficiency.Moreover,the interaction between the dye molecule Eosin Y(EY)and the catalyst is also studied by transient fluorescence spectroscopy.A series of characterizations,such as SEM,TEM,XPS,XRD,UV‐vis,FTIR,transient fluorescence and photocurrent,are conducted,and the results are in good agreement with the experimental result.In addition,the possible reaction mechanism over EY‐sensitized ZIF‐9/CuO under visible light irradiation is proposed.展开更多
Expanded granular sludge bed （EGSB） reactor and bioaugmentation were employed to investigate biohydrogen production with molasses wastewater. The start-up experiments consisted of two stages. In the first stage （0 ...Expanded granular sludge bed （EGSB） reactor and bioaugmentation were employed to investigate biohydrogen production with molasses wastewater. The start-up experiments consisted of two stages. In the first stage （0 - 24d） seeded with activated sludge, the butyric acid type-fermentation formed when the initial expanding rate, organic loading rate （OLR）, the initial redox potential （ORP） and hydraulic retention time （HRT） were 10%, 10.0 kg COD/（m^3·d）, -215 mV and 6.7 h, respectively. At the beginning of the second stage on day 25, the novel hydrogen-producing fermentative bacterial strain B49 （AF481148 in EMBL） were inoculated into the reactor under the condition of OLR 16. 0 kg COD/（m^3·d）, ORP and HRT about - 139 mV and 6.7 h, respectively, and then the reaction system transformed to ethanol-type fermentation gradually with the increase in OLR. When OLR, ORP and HRT were about 94.3 kg COD/（m^3·d）, -250 mV and 1.7 h, respectively, the system achieved the maximum hydrogen-producing rate of 282.6 mL H2/L reactor·h and hydrogen percentage of 51% -53% in the biogas.展开更多
Photocatalytic hydrogen peroxide(H_(2)O_(2))production from O_(2) and H2O is an ideal process for solar‐to‐chemical energy conversion.Herein,ZnO nanorods are prepared via a simple hydrothermal method for photocataly...Photocatalytic hydrogen peroxide(H_(2)O_(2))production from O_(2) and H2O is an ideal process for solar‐to‐chemical energy conversion.Herein,ZnO nanorods are prepared via a simple hydrothermal method for photocatalytic H_(2)O_(2) production.The ZnO nanorods exhibit varied performance with different calcination temperatures.Benefiting from calcination,the separation efficiency of photo‐induced carriers is significantly improved,leading to the superior photocatalytic activity for H_(2)O_(2) production.The H_(2)O_(2) produced by ZnO calcined at 300℃ is 285μmol L^(−1),which is over 5 times larger than that produced by untreated ZnO.This work provides an insight into photocatalytic H2O2 production mechanism by ZnO nanorods,and presents a promising strategy to H2O2 production.展开更多
Catalytic hydrogenation of CO2 into methanol and dimethyl ether was carried out over hybrid catalysts consisting of methanol-synthesis catalyst and zeolite. The methanol-synthesis catalyst, Cu/ZnO/Al2O3, was prepared ...Catalytic hydrogenation of CO2 into methanol and dimethyl ether was carried out over hybrid catalysts consisting of methanol-synthesis catalyst and zeolite. The methanol-synthesis catalyst, Cu/ZnO/Al2O3, was prepared by a co-precipitation method. Then it was physically mixed with HZSM-5 zeolite at weight ratios of 2：1, 1：1 and 1：2. The CO2 hydrogenation reaction was conducted in a fixed-bed microreactor at 250℃ and 40 bar in pre-mixed H2/CO2 feed with H2：CO2 molar ratios of 3：1 and 7：1. Products detected include methanol, dimethyl ether, carbon monoxide and water. Conversion of CO2 and yield of oxygenated products were influenced by the weight ratio of Cu/ZnO/Al2O3：HZSM-5 in the hybrid system and also the feed ratio. The Cu/ZnO/Al2O3： HZSM-5 hybrid at 1：1 resulted in methanol yield of 22.0% and was found to be an efficient hybrid catalyst for the CO2 hydrogenation reaction.展开更多
Hydrogen was produced from partial oxidation reforming of DME （dimethyl ether） by spark discharge plasma at atmospheric pressure. A plasma-catalyst reformer was designed. A series of experiments were carried out to ...Hydrogen was produced from partial oxidation reforming of DME （dimethyl ether） by spark discharge plasma at atmospheric pressure. A plasma-catalyst reformer was designed. A series of experiments were carried out to investigate its performance of hydrogen-rich gas production. The effects of reaction temperature, catalyst and flow rate on gas concentrations （volume fraction）, hydrogen yield, DME conversion ratio, specific energy consumption and thermal efficiency were investigated, respectively. The experimental results show that hydrogen concentration and the flow rate of produced H2 are improved when temperature increases from 300 ℃ to 700 ℃. Hydrogen yield, hydrogen concentration and the flow rate of produced H2 are substantially improved in the use of Fe-based catalyst at high temperature. Moreover, hydrogen yield and thermal efficiency are improved and change slightly when flow rate increases. When catalyst is 12 g, and flow rate increases from 35 mL/min to 210 mL/min, hydrogen yield decreases from 66.4% to 57.7%, and thermal efficiency decreases from 35.6% to 30.9%. It is anticipated that the results would serve as a good guideline to the application of hydrogen generation from hydrocarbon fuels by plasma reforming onboard.展开更多
The electrocatalytic carbon dioxide reduction reaction(CO_(2) RR)producing HCOOH and CO is one of the most promising approaches for storing renewable electricity as chemical energy in fuels.SnO_(2) is a good catalyst ...The electrocatalytic carbon dioxide reduction reaction(CO_(2) RR)producing HCOOH and CO is one of the most promising approaches for storing renewable electricity as chemical energy in fuels.SnO_(2) is a good catalyst for CO_(2)-to-HCOOH or CO_(2)-to-CO conversion,with different crystal planes participating the catalytic process.Among them,(110)surface SnO_(2) is very stable and easy to synthesisze.By changing the ratio of Sn:O for SnO_(2)(110),we have two typical SnO_(2) thin films:fully oxidized(stoichiometric)and partially reduced.In this work,we are concerned with different metals(Fe,Co,Ni,Cu,Ru,Rh,Pd,Ag,Os,Ir,Pt,and Au)-doped SnO_(2)(110)with different activity and selectivity for CO_(2) RR.All these changes are manipulated by adjusting the ratio of Sn:O in(110)surface.The results show that stochiometric and reduced Cu/Ag doped SnO_(2)(110)have different selectivity for CO_(2) RR.More specifically,stochiometric Cu/Ag-doped SnO_(2)(110)tends to generate CO(g).Meanwhile,the reduced surface tends to generate HCOOH(g).Moreover,we also considered the competitive hydrogen evolution reaction(HER).The catalysts SnO_(2)(110)doped by Ru,Rh,Pd,Os,Ir,and Pt have high activity for HER,and others are good catalysts for CO_(2) RR.展开更多
The hydrogen abstraction reaction of methanol with fluorine atoms can produce HF and CH_(3)O or CH_(2)OH radicals,which are important in the environment,combustion,radiation,and interstellar chemistry.In this work,the...The hydrogen abstraction reaction of methanol with fluorine atoms can produce HF and CH_(3)O or CH_(2)OH radicals,which are important in the environment,combustion,radiation,and interstellar chemistry.In this work,the dynamics of this typical reaction is investigated by the quasi-classical trajectory method based on a recently developed globally accurate full-dimensional potential energy surface.Particularly,the vibrational state distributions of the polyatomic products CH_(3)O and CH_(2)OH are determined by using the normal mode analysis method.It is found that CH_(3)O and CH_(2)OH are dominantly populated in the ground state when the reactants are at the ground ro-vibrational state.The OH stretching mode,torsional mode,H_(2)CO out-of-plane bending mode and their combination bands in the CH_(2)OH product can be effectively excited once the OH stretching mode of the reactant CH_(3)OH is excited to the first vibrationally excited state.Most of the available energy flows into the HF vibrational energy and the translational energy in both channels,while the radical products,CH_(3)O or CH_(2)OH,receive a small amount of energy,consistent with experiment,which is an indication of its spectator nature.展开更多
Although photocatalytic water splitting has excellent potential for converting solar energy into chemical energy,the challenging charge separation process and sluggish surface catalytic reactions significantly limit p...Although photocatalytic water splitting has excellent potential for converting solar energy into chemical energy,the challenging charge separation process and sluggish surface catalytic reactions significantly limit progress in solar energy conversion using semiconductor photocatalysts.Herein,we demonstrate a feasible strategy involving the surface assembly of cobalt oxide species(CoO_(x))on a visible-light-responsive Cd_(0.9)Zn_(0.1)S(CZS)photocatalyst to fabricate a hierarchical CZS@CoO_(x) heterostructure.The unique hierarchical structure effectively accelerates the directional transfer of photogenerated charges,reducing charge recombination through the smooth interfacial heterojunction between CZS and CoO_(x),as evidenced by photoluminescence(PL)spectroscopy and various electrochemical characterizations.The surface cobalt species on the CZS material also act as efficient cocatalysts for photocatalytic hydrogen production,with activity even higher than that of noble metals.The well-defined CZS@CoO_(x) heterostructure not only enhances the interfacial separation of photoinduced charges,but also improves surface catalytic reactions.This leads to superior photocatalytic performances,with an apparent quantum efficiency of 20%at 420 nm for visible-light-driven hydrogen generation,which is one of the highest quantum efficiencies measured among noble-metal-free photocatalysts.Our work presents a potential pathway for controlling complex charge separation and catalytic reaction processes in photocatalysis,guiding the practical development of artificial photocatalysts for successful transformation of solar to chemical energy.展开更多
This paper describes the preparation and evaluation of a micro-sphere catalytic complex for the hydrogen production in a Reactive Sorption Enhanced Reforming （ReSER） process. The catalytic complex made by a spray te...This paper describes the preparation and evaluation of a micro-sphere catalytic complex for the hydrogen production in a Reactive Sorption Enhanced Reforming （ReSER） process. The catalytic complex made by a spray technique has a dual function containing Ni as a catalytic material and CaO as an adsorption material used in the ReSER process. The attrition characteristics of the catalytic complex are acceptable for the commercial used. The nano GaCO3 material used as a precursor of CaO showed a desirable durability with a CO2 sorption capacity of 0.6 mol CO2/kg after 10 repeating cycles under the carbonation temperature of 600 ℃, a CO2 partial pressure of 0.02 MPa, and a calcination temperature of 750 ℃ in N2 measured by a thermal gravimetric analyzer. The testing of the catalytic complex for ReSER showed a hydrogen yield of over 95 % （v/v） in the laboratory fixed fluidized bed reactor. The catalytic system has an attractive prospect in the ReSER process for hydrogen production, especially in the fluidized mode where reactor and regenerator combined in a cycling process.展开更多
文摘为制备具有高催化活性的纳米多孔Ni基合金电极用于碱性电解水产氢,首先制备了Ni、NiCo、NiCu和NiFe 4种Ni基合金条带;基于NiCu和NiCo合金体系,利用脱合金化法制备了纳米多孔NiCu和NiCo合金;采用XRD、BET、TEM、LSV等方法分析Ni基合金的晶体结构、形貌结构和电化学性能.结果表明:Ni基合金均为面心立方晶型的单相固溶体;纳米多孔NiCo合金具有均匀的多孔结构,孔径分布为3~6 nm;与原Ni基合金相比,纳米多孔NiCu和NiCo合金的过电势和塔菲尔(Tafel)斜率大幅降低,催化活性明显提高,纳米多孔NiCo合金在电流密度20 m A/cm^2下过电势为140 m V,Tafel斜率为60 m V/dec),接近于Pt.因此,选择具有协同作用的掺杂元素和构建纳米多孔结构是提高Ni基合金电极产氢反应催化活性的有效途径.
基金the National Natural Science Foundation of China(52102111)the Natural Science Foundation of Hubei Province(No.2021CFB218)the Unveils List System Science and Technology Project of Hubei Provincial Science and Technology Department(No.2021BEC016)。
基金supported by the National Basic Research Program of China(973 Program2013CB632405)+3 种基金the National Natural Science Foundation of China(2142530921033003)the Specialized Research Fund for the Doctoral Program of Higher Education(20133514110003)the Department of Education of Fujian Province in China~~
文摘A thermal nitridation route for the assembly and polymerization of molecular triazine units to heptazine-based covalent frameworks has been successfully established. The obtained conjugated carbon nitride polymers feature nanostructures that show enhanced photocatalytic reactivity for hydrogen production under visible light irradiation.
文摘Molybdenum sulfides are promising electrocatalysts for the hydrogen evolution reaction(HER).Sand Mo‐related species have been proposed as the active site for forming adsorbed hydrogen to initiate the HER;however,the nature of the interaction between Mo centers and S ligands is unclear.Further,the development of cost‐effective water‐splitting systems using neutral water as a proton source for H2evolution is highly desirable,whereas the mechanism of the HER at neutral pH is rarely discussed.Here,the structural change in the Mo?Mo and S?S species in a synthesized molybdenum sulfide was monitored at neutral pH using in situ electrochemical Raman spectroscopy.Analysis of the potential dependent Raman spectra revealed that the band assigned to a terminal S?S species emerged along with synchronized changes in the frequency of the Mo?Mo,Mo3?μ3S,and Mo?S vibrational bands.This indicates that Mo?Mo bonds and terminal S?S ligands play synergistic roles in facilitating hydrogen evolution,likely via the internal reorganization of trinuclear Mo3?thio species.The nature and role of metal‐ligand interactions in the HER revealed in this study demonstrated a mechanism that is distinct from those reported previously in which the S or Mo sites function independently.
基金supported by the National Natural Science Foundation of China(21433007,21603274,41663012)the Ningxia Low-Grade Resource High Value Utilization and Environmental Chemical Integration Technology Innovation Team Project,North Minzu University~~
文摘An efficient CuO‐modified zeolitic imidazolate framework‐9(ZIF‐9)photocatalyst is successfully prepared at room temperature under mild conditions.It is observed that the ZIF‐9/CuO photocatalyst is effective for H2generation under visible light with sacrificial agent conditions.When the CuO is introduced,the photocatalytic properties of ZIF‐9are greatly improved and when the content of CuO is40%,the photocatalytic activity reaches a maximum of78.74μmol after5h.This results from the200–300nm cube structure of ZIF‐9being able to adsorb more dye molecules and the CuO,which connects with ZIF‐9,greatly improving the electronic transmission efficiency.Moreover,the interaction between the dye molecule Eosin Y(EY)and the catalyst is also studied by transient fluorescence spectroscopy.A series of characterizations,such as SEM,TEM,XPS,XRD,UV‐vis,FTIR,transient fluorescence and photocurrent,are conducted,and the results are in good agreement with the experimental result.In addition,the possible reaction mechanism over EY‐sensitized ZIF‐9/CuO under visible light irradiation is proposed.
文摘Expanded granular sludge bed （EGSB） reactor and bioaugmentation were employed to investigate biohydrogen production with molasses wastewater. The start-up experiments consisted of two stages. In the first stage （0 - 24d） seeded with activated sludge, the butyric acid type-fermentation formed when the initial expanding rate, organic loading rate （OLR）, the initial redox potential （ORP） and hydraulic retention time （HRT） were 10%, 10.0 kg COD/（m^3·d）, -215 mV and 6.7 h, respectively. At the beginning of the second stage on day 25, the novel hydrogen-producing fermentative bacterial strain B49 （AF481148 in EMBL） were inoculated into the reactor under the condition of OLR 16. 0 kg COD/（m^3·d）, ORP and HRT about - 139 mV and 6.7 h, respectively, and then the reaction system transformed to ethanol-type fermentation gradually with the increase in OLR. When OLR, ORP and HRT were about 94.3 kg COD/（m^3·d）, -250 mV and 1.7 h, respectively, the system achieved the maximum hydrogen-producing rate of 282.6 mL H2/L reactor·h and hydrogen percentage of 51% -53% in the biogas.
文摘Photocatalytic hydrogen peroxide(H_(2)O_(2))production from O_(2) and H2O is an ideal process for solar‐to‐chemical energy conversion.Herein,ZnO nanorods are prepared via a simple hydrothermal method for photocatalytic H_(2)O_(2) production.The ZnO nanorods exhibit varied performance with different calcination temperatures.Benefiting from calcination,the separation efficiency of photo‐induced carriers is significantly improved,leading to the superior photocatalytic activity for H_(2)O_(2) production.The H_(2)O_(2) produced by ZnO calcined at 300℃ is 285μmol L^(−1),which is over 5 times larger than that produced by untreated ZnO.This work provides an insight into photocatalytic H2O2 production mechanism by ZnO nanorods,and presents a promising strategy to H2O2 production.
文摘Catalytic hydrogenation of CO2 into methanol and dimethyl ether was carried out over hybrid catalysts consisting of methanol-synthesis catalyst and zeolite. The methanol-synthesis catalyst, Cu/ZnO/Al2O3, was prepared by a co-precipitation method. Then it was physically mixed with HZSM-5 zeolite at weight ratios of 2：1, 1：1 and 1：2. The CO2 hydrogenation reaction was conducted in a fixed-bed microreactor at 250℃ and 40 bar in pre-mixed H2/CO2 feed with H2：CO2 molar ratios of 3：1 and 7：1. Products detected include methanol, dimethyl ether, carbon monoxide and water. Conversion of CO2 and yield of oxygenated products were influenced by the weight ratio of Cu/ZnO/Al2O3：HZSM-5 in the hybrid system and also the feed ratio. The Cu/ZnO/Al2O3： HZSM-5 hybrid at 1：1 resulted in methanol yield of 22.0% and was found to be an efficient hybrid catalyst for the CO2 hydrogenation reaction.
基金Project(21106002)supported by the National Natural Science Foundation of ChinaProject(2010DFA72760)supported by the Collaboration on Cutting-Edge Technology Development of Electric Vehicle,China
文摘Hydrogen was produced from partial oxidation reforming of DME （dimethyl ether） by spark discharge plasma at atmospheric pressure. A plasma-catalyst reformer was designed. A series of experiments were carried out to investigate its performance of hydrogen-rich gas production. The effects of reaction temperature, catalyst and flow rate on gas concentrations （volume fraction）, hydrogen yield, DME conversion ratio, specific energy consumption and thermal efficiency were investigated, respectively. The experimental results show that hydrogen concentration and the flow rate of produced H2 are improved when temperature increases from 300 ℃ to 700 ℃. Hydrogen yield, hydrogen concentration and the flow rate of produced H2 are substantially improved in the use of Fe-based catalyst at high temperature. Moreover, hydrogen yield and thermal efficiency are improved and change slightly when flow rate increases. When catalyst is 12 g, and flow rate increases from 35 mL/min to 210 mL/min, hydrogen yield decreases from 66.4% to 57.7%, and thermal efficiency decreases from 35.6% to 30.9%. It is anticipated that the results would serve as a good guideline to the application of hydrogen generation from hydrocarbon fuels by plasma reforming onboard.
基金supported by the Ministry of Science and Technology(No.2017YFA0204904,No.2016YFA0400900,and No.2016YFA0200600)the National Natural Science Foundation of China(No.21973086 and No.21633006)。
文摘The electrocatalytic carbon dioxide reduction reaction(CO_(2) RR)producing HCOOH and CO is one of the most promising approaches for storing renewable electricity as chemical energy in fuels.SnO_(2) is a good catalyst for CO_(2)-to-HCOOH or CO_(2)-to-CO conversion,with different crystal planes participating the catalytic process.Among them,(110)surface SnO_(2) is very stable and easy to synthesisze.By changing the ratio of Sn:O for SnO_(2)(110),we have two typical SnO_(2) thin films:fully oxidized(stoichiometric)and partially reduced.In this work,we are concerned with different metals(Fe,Co,Ni,Cu,Ru,Rh,Pd,Ag,Os,Ir,Pt,and Au)-doped SnO_(2)(110)with different activity and selectivity for CO_(2) RR.All these changes are manipulated by adjusting the ratio of Sn:O in(110)surface.The results show that stochiometric and reduced Cu/Ag doped SnO_(2)(110)have different selectivity for CO_(2) RR.More specifically,stochiometric Cu/Ag-doped SnO_(2)(110)tends to generate CO(g).Meanwhile,the reduced surface tends to generate HCOOH(g).Moreover,we also considered the competitive hydrogen evolution reaction(HER).The catalysts SnO_(2)(110)doped by Ru,Rh,Pd,Os,Ir,and Pt have high activity for HER,and others are good catalysts for CO_(2) RR.
基金supported by the National Natural Science Foundation of China(No.21973009 to Jun Li)the Chongqing Municipal Natural Science Foundation(No.cstc2019jcyj-msxm X0087 to Jun Li)the support from the Talent Introduction Project of Hubei Polytechnic University(No.21xjz01R)。
文摘The hydrogen abstraction reaction of methanol with fluorine atoms can produce HF and CH_(3)O or CH_(2)OH radicals,which are important in the environment,combustion,radiation,and interstellar chemistry.In this work,the dynamics of this typical reaction is investigated by the quasi-classical trajectory method based on a recently developed globally accurate full-dimensional potential energy surface.Particularly,the vibrational state distributions of the polyatomic products CH_(3)O and CH_(2)OH are determined by using the normal mode analysis method.It is found that CH_(3)O and CH_(2)OH are dominantly populated in the ground state when the reactants are at the ground ro-vibrational state.The OH stretching mode,torsional mode,H_(2)CO out-of-plane bending mode and their combination bands in the CH_(2)OH product can be effectively excited once the OH stretching mode of the reactant CH_(3)OH is excited to the first vibrationally excited state.Most of the available energy flows into the HF vibrational energy and the translational energy in both channels,while the radical products,CH_(3)O or CH_(2)OH,receive a small amount of energy,consistent with experiment,which is an indication of its spectator nature.
文摘Although photocatalytic water splitting has excellent potential for converting solar energy into chemical energy,the challenging charge separation process and sluggish surface catalytic reactions significantly limit progress in solar energy conversion using semiconductor photocatalysts.Herein,we demonstrate a feasible strategy involving the surface assembly of cobalt oxide species(CoO_(x))on a visible-light-responsive Cd_(0.9)Zn_(0.1)S(CZS)photocatalyst to fabricate a hierarchical CZS@CoO_(x) heterostructure.The unique hierarchical structure effectively accelerates the directional transfer of photogenerated charges,reducing charge recombination through the smooth interfacial heterojunction between CZS and CoO_(x),as evidenced by photoluminescence(PL)spectroscopy and various electrochemical characterizations.The surface cobalt species on the CZS material also act as efficient cocatalysts for photocatalytic hydrogen production,with activity even higher than that of noble metals.The well-defined CZS@CoO_(x) heterostructure not only enhances the interfacial separation of photoinduced charges,but also improves surface catalytic reactions.This leads to superior photocatalytic performances,with an apparent quantum efficiency of 20%at 420 nm for visible-light-driven hydrogen generation,which is one of the highest quantum efficiencies measured among noble-metal-free photocatalysts.Our work presents a potential pathway for controlling complex charge separation and catalytic reaction processes in photocatalysis,guiding the practical development of artificial photocatalysts for successful transformation of solar to chemical energy.
基金supports from Sinopec of China and from National Science Foundation of China (NSFC) under contracts No.20676119supports from Sinopec of China and from National Science Foundation of China (NSFC) under contracts No. 20876142 respectively
文摘This paper describes the preparation and evaluation of a micro-sphere catalytic complex for the hydrogen production in a Reactive Sorption Enhanced Reforming （ReSER） process. The catalytic complex made by a spray technique has a dual function containing Ni as a catalytic material and CaO as an adsorption material used in the ReSER process. The attrition characteristics of the catalytic complex are acceptable for the commercial used. The nano GaCO3 material used as a precursor of CaO showed a desirable durability with a CO2 sorption capacity of 0.6 mol CO2/kg after 10 repeating cycles under the carbonation temperature of 600 ℃, a CO2 partial pressure of 0.02 MPa, and a calcination temperature of 750 ℃ in N2 measured by a thermal gravimetric analyzer. The testing of the catalytic complex for ReSER showed a hydrogen yield of over 95 % （v/v） in the laboratory fixed fluidized bed reactor. The catalytic system has an attractive prospect in the ReSER process for hydrogen production, especially in the fluidized mode where reactor and regenerator combined in a cycling process.
