Molybdenum carbides are highly active for CO2 conversion to CO via the reverse water-gas shift(RWGS)reaction, however the large grain size up to micrometers renders its relatively lower active sites utilization effici...Molybdenum carbides are highly active for CO2 conversion to CO via the reverse water-gas shift(RWGS)reaction, however the large grain size up to micrometers renders its relatively lower active sites utilization efficiency while generating CH4 as a by-product. In this work, a homogeneously dispersed molybdenum carbide hybrid catalyst with sub-nanosized cluster(the average size as small as 0.5 nm) is prepared via a facile carbothermal treatment for highly selective CO2-CO reduction. The partially disordered Mo2C clusters are characterized by synchrotron high-resolution XRD and atomic resolution HAADF-STEM analysis, for which the source cause of the disorder is pinpointed by XAFS analysis to be the nitrogen intercalants from the carbonaceous precursor. The partially disordered Mo2C clusters show a RWGS rate as high as 184.4 μmol gMo2C-1s-1 at 400 ℃ with a superior selectivity toward CO(> 99.5%). This work 2 highlights a facile strategy for fabricating highly dispersed and partially disordered Mo2C clusters at a sub-nano size with beneficial N-doping for delivering high catalytic activity and operational stability.展开更多
In this work, a series of Ni-Mo-Mg-O catalysts with mesoporous structure prepared by sol-gel method were investigated for the oxidative dehydrogenation of propane （ODHP）. The techniques of temperature-programmed red...In this work, a series of Ni-Mo-Mg-O catalysts with mesoporous structure prepared by sol-gel method were investigated for the oxidative dehydrogenation of propane （ODHP）. The techniques of temperature-programmed reduction with H2 （H2-TPR）, N2 adsorption-desolption, Fourier transform infrared spectroscopy （FT-IR）, X-ray diffraction （XRD） and X-ray photoelectron spectra （XPS） were employed for catalyst characterization. It is found that the activity of the catalysts for ODHP increases first and then decreases with the increase of Mo content. The catalyst with a Mo/Ni atomic ratio of 1/1 exhibits the best catalytic activity, which gives the propene selectivity of 81.4% at a propane conversion of 11.3% under 600 ~C and maintains the good catalytic performance for 22 h on stream. This is related not only to its high reducibility and dispersion as revealed by TPR and XRD, but also to the formation of more selective oxygen species on the MoOz-NiO interface as identified by XPS.展开更多
Doping enables manipulation of both the electrical and optical properties of halide perovskites.Herein,we incorporated Te^(4+) into Cs_(2)ZrCl_(6) single crystal,simultaneously preserving the vacancy-ordered structure...Doping enables manipulation of both the electrical and optical properties of halide perovskites.Herein,we incorporated Te^(4+) into Cs_(2)ZrCl_(6) single crystal,simultaneously preserving the vacancy-ordered structure,to obtain an efficient yellow-emitting perovskite with a near-unity photoluminescence quantum yield(PLQY≈97.6%).Te^(4+) doping modifies the hue and emission color of pristine Cs_(2)ZrCl_(6),generates new absorption channels,and successfully extends the excitation energy from<280 nm to 360-450 nm range.Detailed spectral characterizations,including ultrafast femtosecond transient absorption measurements,reveal that the bright yellow light is derived from triplet self-trapped excitons.Moreover,further tuning doping concentration enables Te-doped Cs_(2)ZrCl_(6) single crystals to exhibit efficient warm white light emission.This work provides a new perspective for the development and design of stable lead-free perovskites with highly efficient luminescence.展开更多
A hierarchical metal-free catalyst consisting of nitrogen-doped carbon nanotubes decorated onto a silicon carbide (N-CNTs/SiC) macroscopic host structure was prepared. The influence of N-CNTs incorporation on the phys...A hierarchical metal-free catalyst consisting of nitrogen-doped carbon nanotubes decorated onto a silicon carbide (N-CNTs/SiC) macroscopic host structure was prepared. The influence of N-CNTs incorporation on the physical properties of the support was evaluated using different characterization techniques. The catalyst was tested as a metal-free catalyst in the selective oxidation of H2S and steam-free dehydrogenation of ethylbenzene. The N-CNTs/SiC catalyst exhibited extremely good desulfurization performance compared to a Fe2O3/SiC catalyst under less conducive reaction conditions such as low temperature, high space velocity, and a low O2-to-H2S molar ratio. For the dehy-drogenation of ethylbenzene, a higher dehydrogenation activity was obtained with the N-CNTs/SiC catalyst compared to a commercial K-Fe/Al2O3 catalyst. The N-CNTs/SiC catalyst also displayed good stability as a function of time on stream for both reactions, which was attributed to the strong anchoring of the nitrogen dopant in the carbon matrix. The extrudate shape of the SiC support allowed the direct macroscopic shaping of the catalyst for use in a conventional fixed-bed reactor without the problems of catalyst handling, transportation, and pressure drop across the catalyst bed that are encountered with nanoscopic carbon-based catalysts.展开更多
A new hierarchical composite consisted of multi-walled carbon nanotubes （CNTs） layer anchored on macroscopic a-A1203 host matrix was synthesized and used as support for Fischer-Tropsch synthesis （FTS）. The composi...A new hierarchical composite consisted of multi-walled carbon nanotubes （CNTs） layer anchored on macroscopic a-A1203 host matrix was synthesized and used as support for Fischer-Tropsch synthesis （FTS）. The composite constituted by a thin shell of a homogeneous, highly entan-gled and structure-opened carbon nanotubes network and it exhibited a relatively high and fully accessible specific surface area of 76 m2.g-1, compared with that of 5 m2.g-1 of the original a-A1203support. The metal-support interaction between carbon nanotubes surface and cobalt precursor and high effective surface area led to a relatively high dispersion of cobalt nanoparticles. This hierarchically supported cobalt catalyst exhibited a high FTS activity along with an extremely high selectivity towards liquid hydrocarbons compared with the cobalt-based catalyst supported on pristine a-A1203 or on CNTs carriers. This improvement can attribute to the high accessibility of composite surface area com- paring with the macroscopic host structure alone or to the bulk CNTs where the nanoscopic dimension induced a dense packing with low mass transfer which favoured the problem of reactants competitive diffusion towards the cobalt active site. In addition, intrinsic thermal conductivity of decorated CNTs could help the heat dissipating throughout the catalyst body, thus avoiding the formation of local hot spots which appeared in high CO conversion under pure syngas feed in FTS reaction. Cobalt supported on CNTs decorated a-A1203 catalyst also exhibited satisfied high stability during more than 200 h on stream under relatively severe conditions compared with other catalysts reported in the literature. Finally, the macroscopic shape of such composite easily rendered its usage as catalyst support in a fixed-bed configuration without facing problems of transport and pressure drop as encountered with the bulk CNTs.展开更多
The performances of heterogeneous catalysts can be effectively improved by optimizing the catalysts via appropriate structure design.Herein,we show that the catalysis of cuprous sulfide can be boosted by constructing ...The performances of heterogeneous catalysts can be effectively improved by optimizing the catalysts via appropriate structure design.Herein,we show that the catalysis of cuprous sulfide can be boosted by constructing the hybrid structure with Cu_(2)S nanoparticles on amorphous CuSx matrix(Cu_(2)S/CuSx).In the photocatalytic CO_(2) reduction under visible light irradiation,the Cu_(2)S/CuSx exhibited a CO production rate at 4.0μmol h-1 that is 12-fold higher than that of the general Cu_(2)S catalyst.Further characterizations reveal that the Cu_(2)S/CuSx has two reaction systems that realize the biomimetic catalysis,involving in the light reaction on the Cu_(2)S nanoparticle-CuSx matrix heterojunctions for proton/electron production,and the dark reaction on the defect-rich CuSx for CO_(2) reduction.The CuSx matrix could efficiently activate CO_(2) and stabilize the split hydrogen species to hinder undesired hydrogen evolution reaction,which benefits the proton-electron transfer to reduce CO_(2),a key step for bridging the two reaction systems.展开更多
The distribution patterns of rare earth elements(REEs)in fine-grained materials in various depositions were often found to be similar to those of the aeolian sediments deposited in the Loess Plateau in North China and...The distribution patterns of rare earth elements(REEs)in fine-grained materials in various depositions were often found to be similar to those of the aeolian sediments deposited in the Loess Plateau in North China and the fine-grained materials were suggested to be derived from wind-blown dust.However,increasing evidence indicated that the REEs in the water-soluble portion of atmospheric depositions also displayed similar patterns to those of aeolian sediments.In this study,water-soluble REEs in three atmospheric depositions collected from different climatic zones in China were adsorbed with two adsorbents with distinct adsorption capacity,glass powder,and co-precipitated iron hydroxide.The results showed that the REEs adsorbed by the two adsorbents displayed patterns similar to those of the original atmospheric depositions.The typical characteristics of the REE patterns of atmospheric deposition can be well reproduced in the adsorbed REEs.The higher the REE concentrations in the atmospheric depositions,or the higher adsorption efficiency of the adsorbents,the better reproducibility of the REEs patterns.The results suggest that the REEs of the fine-grained materials in various sediments,which have a high adsorption capacity,especially those deposited in South China,may come from the water-soluble REEs in atmospheric deposition,and may not be appropriate tracers of wind-blown dust from North China.展开更多
In this paper, we demonstrate a color tunable white organic light-emitting devices （WOLEDs） based on the two complementary color strategies by introducing two-dimensional （2-D） dual periodic gratings. It is possib...In this paper, we demonstrate a color tunable white organic light-emitting devices （WOLEDs） based on the two complementary color strategies by introducing two-dimensional （2-D） dual periodic gratings. It is possible to tune the color in a range between cold-white and warmwhite by simply operating the polarization of polarizer in front of the microstructured WOLEDs. Experimental and numerical results demonstrate that color tunability of the WOLEDs comes from the effect of the 2-D dual periodic gratings by exciting the surface plasmon-polariton （SPP） resonance associated with the cathode/organic interface. The electroluminescence （EL） performance of the WOLEDs have also been improved due to the effective light extraction by excitation and out-coupling of the SPP modes, and a 39.65% enhancement of current efficiency has been obtained compared to the conventional planar devices.展开更多
Accurate and highly efficient approaches to obtain mission opportunities are still the goals of mission planners of interplanetary explorations.The search for launch opportunities not only determines the specified lau...Accurate and highly efficient approaches to obtain mission opportunities are still the goals of mission planners of interplanetary explorations.The search for launch opportunities not only determines the specified launch window of the mission but also presents the performance requirements for the interplanetary probe and its launch vehicle.An effective method, namely the two-dimensional launch window method, is developed from a completely new perspective to determine all the launch opportunities of the mission in this research.For a fixed launch time,the method to determine all the time windows in the dimension of Time-of-Flight(TOF) is firstly proposed and these time windows represent all the launch opportunities for the given launch time.And then, the two-dimensional launch window method is proposed, which computes the time windows in both the launch time and TOF dimensions to achieve all launch opportunities of the mission.Numerical examples are provided to demonstrate the accuracy and high efficiency of the method.Compared with the widely-used pock-chop plot method, the proposed method reduces the computational time by two orders of magnitude for the same search precision, and thus is especially suitable for the cases involving rapid, high-precision, and/or large-scale searches for mission opportunities.展开更多
Dimethyl ether(DME),as a promising alternative to diesel fuel and liquefied petroleum gas,has attracted considerable attention in catalysis domain.The catalytic direct synthesis of DME from syngas is an upand-coming r...Dimethyl ether(DME),as a promising alternative to diesel fuel and liquefied petroleum gas,has attracted considerable attention in catalysis domain.The catalytic direct synthesis of DME from syngas is an upand-coming route but remains a challenge.In this work,we firstly prepared a Cu-embedded porous Al_(2)O_(3)bifunctional catalyst(Cu@Al_(2)O_(3)-dp)by filling Cu-1,3,5-benzenetricarboxylate metal–organic framework(Cu-BTC MOF)with Al(OH)_(3) followed by a two-step calcination process(400℃for 4 h and 600℃for1 h),exhibiting excellent catalytic performance for direct synthesis of DME from syngas.Cu@Al_(2)O_(3)-dp catalyst demonstrates much higher CO conversion(25.7%vs.15.4%)and extremely higher DME selectivity(90.4%vs.63.9%)with the increased catalytic stability compared to the supported Cu catalyst on MOF-derived porous Al_(2)O_(3)(Cu/Al_(2)O_(3))prepared by incipient wetness impregnation method,ascribed to the unique embedding-type structure,promoted Cu dispersion and stronger metal-support interaction.This work not only provides an efficient syngas-to-DME catalyst,but also paves a new way for designing highly-efficient core-shell bifunctional catalysts for diverse consecutive reactions.展开更多
Developing an efficientmethod to improve the photocatalytic efficiency of graphitic carbon nitride(g-C3 N4)is of great significance for solar H2 production.Electronic structure modulation has been considered one of th...Developing an efficientmethod to improve the photocatalytic efficiency of graphitic carbon nitride(g-C3 N4)is of great significance for solar H2 production.Electronic structure modulation has been considered one of the most crucial strategies to improving the photocatalytic efficiency of g-C_(3)N_(4),but how to efficiently modulate its electronic structure remains a huge challenge.Herein,we,for the first time,report a facile and highly-efficient approach to modulating the electronic structure of g-C_(3)N_(4)through single Ag atom implantation with a Ag_(1)-N_(3)coordination configuration into the g-C_(3)N_(4)framework.展开更多
基金中国博士后科学基金(2021M693125)大连市高层次人才创新支持计划(2019RT09)+1 种基金中国科学院洁净能源创新研究院合作基金(DNL202016,DNL202019)中国科学院洁净能源创新研究院-榆林学院联合基金(YLU-DNL Fund 2021002,YLU-DNL Fund 2021009).
基金the National Natural Science Foundation of China(21872144,21972140 and 91645117)Liaoning Revitalization Talents Program(XLYC1907053)+2 种基金CAS Youth Innovation Promotion Association(2018220)Talents Innovation Project of Dalian City(2017RQ032 and 2016RD04)China Postdoctoral Science Foundation(2019TQ0314,2018M641726 and 2019M661146)。
文摘Molybdenum carbides are highly active for CO2 conversion to CO via the reverse water-gas shift(RWGS)reaction, however the large grain size up to micrometers renders its relatively lower active sites utilization efficiency while generating CH4 as a by-product. In this work, a homogeneously dispersed molybdenum carbide hybrid catalyst with sub-nanosized cluster(the average size as small as 0.5 nm) is prepared via a facile carbothermal treatment for highly selective CO2-CO reduction. The partially disordered Mo2C clusters are characterized by synchrotron high-resolution XRD and atomic resolution HAADF-STEM analysis, for which the source cause of the disorder is pinpointed by XAFS analysis to be the nitrogen intercalants from the carbonaceous precursor. The partially disordered Mo2C clusters show a RWGS rate as high as 184.4 μmol gMo2C-1s-1 at 400 ℃ with a superior selectivity toward CO(> 99.5%). This work 2 highlights a facile strategy for fabricating highly dispersed and partially disordered Mo2C clusters at a sub-nano size with beneficial N-doping for delivering high catalytic activity and operational stability.
基金supported by the National Natural Science Foundation of China (20776089)the New Century Excellent Talent Project of China(NCET-05-0783)
文摘In this work, a series of Ni-Mo-Mg-O catalysts with mesoporous structure prepared by sol-gel method were investigated for the oxidative dehydrogenation of propane （ODHP）. The techniques of temperature-programmed reduction with H2 （H2-TPR）, N2 adsorption-desolption, Fourier transform infrared spectroscopy （FT-IR）, X-ray diffraction （XRD） and X-ray photoelectron spectra （XPS） were employed for catalyst characterization. It is found that the activity of the catalysts for ODHP increases first and then decreases with the increase of Mo content. The catalyst with a Mo/Ni atomic ratio of 1/1 exhibits the best catalytic activity, which gives the propene selectivity of 81.4% at a propane conversion of 11.3% under 600 ~C and maintains the good catalytic performance for 22 h on stream. This is related not only to its high reducibility and dispersion as revealed by TPR and XRD, but also to the formation of more selective oxygen species on the MoOz-NiO interface as identified by XPS.
基金supported by the National Natural Science Foundation of China (21833009, 22088102)the National Key Research and Development Program of China (2017YFA0204800)+5 种基金the Scientific Instrument Developing Project of the Chinese Academy of Sciences (YJKYYQ20190003)the Innovation Foundation of Dalian Institute of Chemical Physics (DICP I202127)the Liao Ning Revitalization Talents Program (XLYC1802126, XLYC1907053)the Dalian City Foundation for Science and Technology Innovation (2019J12GX031)the CAS Youth Innovation Promotion Association (2018220)China Postdoctoral Science Foundation (2020 M670800)。
文摘Doping enables manipulation of both the electrical and optical properties of halide perovskites.Herein,we incorporated Te^(4+) into Cs_(2)ZrCl_(6) single crystal,simultaneously preserving the vacancy-ordered structure,to obtain an efficient yellow-emitting perovskite with a near-unity photoluminescence quantum yield(PLQY≈97.6%).Te^(4+) doping modifies the hue and emission color of pristine Cs_(2)ZrCl_(6),generates new absorption channels,and successfully extends the excitation energy from<280 nm to 360-450 nm range.Detailed spectral characterizations,including ultrafast femtosecond transient absorption measurements,reveal that the bright yellow light is derived from triplet self-trapped excitons.Moreover,further tuning doping concentration enables Te-doped Cs_(2)ZrCl_(6) single crystals to exhibit efficient warm white light emission.This work provides a new perspective for the development and design of stable lead-free perovskites with highly efficient luminescence.
基金financially supported by a European project (FREECATS) under a contract number NMP-2011-2.2-4 "Novel materials for replacement of strategic or scarce raw materials"
文摘A hierarchical metal-free catalyst consisting of nitrogen-doped carbon nanotubes decorated onto a silicon carbide (N-CNTs/SiC) macroscopic host structure was prepared. The influence of N-CNTs incorporation on the physical properties of the support was evaluated using different characterization techniques. The catalyst was tested as a metal-free catalyst in the selective oxidation of H2S and steam-free dehydrogenation of ethylbenzene. The N-CNTs/SiC catalyst exhibited extremely good desulfurization performance compared to a Fe2O3/SiC catalyst under less conducive reaction conditions such as low temperature, high space velocity, and a low O2-to-H2S molar ratio. For the dehy-drogenation of ethylbenzene, a higher dehydrogenation activity was obtained with the N-CNTs/SiC catalyst compared to a commercial K-Fe/Al2O3 catalyst. The N-CNTs/SiC catalyst also displayed good stability as a function of time on stream for both reactions, which was attributed to the strong anchoring of the nitrogen dopant in the carbon matrix. The extrudate shape of the SiC support allowed the direct macroscopic shaping of the catalyst for use in a conventional fixed-bed reactor without the problems of catalyst handling, transportation, and pressure drop across the catalyst bed that are encountered with nanoscopic carbon-based catalysts.
基金the China Scholarship Council (CSC) for the PhD grant during his stay at the LMSPC
文摘A new hierarchical composite consisted of multi-walled carbon nanotubes （CNTs） layer anchored on macroscopic a-A1203 host matrix was synthesized and used as support for Fischer-Tropsch synthesis （FTS）. The composite constituted by a thin shell of a homogeneous, highly entan-gled and structure-opened carbon nanotubes network and it exhibited a relatively high and fully accessible specific surface area of 76 m2.g-1, compared with that of 5 m2.g-1 of the original a-A1203support. The metal-support interaction between carbon nanotubes surface and cobalt precursor and high effective surface area led to a relatively high dispersion of cobalt nanoparticles. This hierarchically supported cobalt catalyst exhibited a high FTS activity along with an extremely high selectivity towards liquid hydrocarbons compared with the cobalt-based catalyst supported on pristine a-A1203 or on CNTs carriers. This improvement can attribute to the high accessibility of composite surface area com- paring with the macroscopic host structure alone or to the bulk CNTs where the nanoscopic dimension induced a dense packing with low mass transfer which favoured the problem of reactants competitive diffusion towards the cobalt active site. In addition, intrinsic thermal conductivity of decorated CNTs could help the heat dissipating throughout the catalyst body, thus avoiding the formation of local hot spots which appeared in high CO conversion under pure syngas feed in FTS reaction. Cobalt supported on CNTs decorated a-A1203 catalyst also exhibited satisfied high stability during more than 200 h on stream under relatively severe conditions compared with other catalysts reported in the literature. Finally, the macroscopic shape of such composite easily rendered its usage as catalyst support in a fixed-bed configuration without facing problems of transport and pressure drop as encountered with the bulk CNTs.
基金supported by the National Key Research and Development Program of China(2018YFD1000806-01)the National Natural Science Foundation of China(21822203 and 21932006)+1 种基金the Natural Science Foundation of Zhejiang Province(LR18B030002)China Postdoctoral Science Foundation(2020M671020)。
文摘The performances of heterogeneous catalysts can be effectively improved by optimizing the catalysts via appropriate structure design.Herein,we show that the catalysis of cuprous sulfide can be boosted by constructing the hybrid structure with Cu_(2)S nanoparticles on amorphous CuSx matrix(Cu_(2)S/CuSx).In the photocatalytic CO_(2) reduction under visible light irradiation,the Cu_(2)S/CuSx exhibited a CO production rate at 4.0μmol h-1 that is 12-fold higher than that of the general Cu_(2)S catalyst.Further characterizations reveal that the Cu_(2)S/CuSx has two reaction systems that realize the biomimetic catalysis,involving in the light reaction on the Cu_(2)S nanoparticle-CuSx matrix heterojunctions for proton/electron production,and the dark reaction on the defect-rich CuSx for CO_(2) reduction.The CuSx matrix could efficiently activate CO_(2) and stabilize the split hydrogen species to hinder undesired hydrogen evolution reaction,which benefits the proton-electron transfer to reduce CO_(2),a key step for bridging the two reaction systems.
基金financially supported by the National Natural Science Foundation of China (Grant Nos. 41473093 and 41271212)。
文摘The distribution patterns of rare earth elements(REEs)in fine-grained materials in various depositions were often found to be similar to those of the aeolian sediments deposited in the Loess Plateau in North China and the fine-grained materials were suggested to be derived from wind-blown dust.However,increasing evidence indicated that the REEs in the water-soluble portion of atmospheric depositions also displayed similar patterns to those of aeolian sediments.In this study,water-soluble REEs in three atmospheric depositions collected from different climatic zones in China were adsorbed with two adsorbents with distinct adsorption capacity,glass powder,and co-precipitated iron hydroxide.The results showed that the REEs adsorbed by the two adsorbents displayed patterns similar to those of the original atmospheric depositions.The typical characteristics of the REE patterns of atmospheric deposition can be well reproduced in the adsorbed REEs.The higher the REE concentrations in the atmospheric depositions,or the higher adsorption efficiency of the adsorbents,the better reproducibility of the REEs patterns.The results suggest that the REEs of the fine-grained materials in various sediments,which have a high adsorption capacity,especially those deposited in South China,may come from the water-soluble REEs in atmospheric deposition,and may not be appropriate tracers of wind-blown dust from North China.
基金The authors gratefully acknowledge support from the National Basic Research Program of China （973 Program） （No. 2013CBA01700）, the National Natural Science Foundation of China （NSFC） （Grant Nos. 61322402, 91233123 and 61177024）.
文摘In this paper, we demonstrate a color tunable white organic light-emitting devices （WOLEDs） based on the two complementary color strategies by introducing two-dimensional （2-D） dual periodic gratings. It is possible to tune the color in a range between cold-white and warmwhite by simply operating the polarization of polarizer in front of the microstructured WOLEDs. Experimental and numerical results demonstrate that color tunability of the WOLEDs comes from the effect of the 2-D dual periodic gratings by exciting the surface plasmon-polariton （SPP） resonance associated with the cathode/organic interface. The electroluminescence （EL） performance of the WOLEDs have also been improved due to the effective light extraction by excitation and out-coupling of the SPP modes, and a 39.65% enhancement of current efficiency has been obtained compared to the conventional planar devices.
基金co-supported by the National Natural Science Foundation of China(No.11502300)the Science and Technology on Electro-optic Control Laboratory and the Aerospace Science Foundation of China(No.20165196018)。
文摘Accurate and highly efficient approaches to obtain mission opportunities are still the goals of mission planners of interplanetary explorations.The search for launch opportunities not only determines the specified launch window of the mission but also presents the performance requirements for the interplanetary probe and its launch vehicle.An effective method, namely the two-dimensional launch window method, is developed from a completely new perspective to determine all the launch opportunities of the mission in this research.For a fixed launch time,the method to determine all the time windows in the dimension of Time-of-Flight(TOF) is firstly proposed and these time windows represent all the launch opportunities for the given launch time.And then, the two-dimensional launch window method is proposed, which computes the time windows in both the launch time and TOF dimensions to achieve all launch opportunities of the mission.Numerical examples are provided to demonstrate the accuracy and high efficiency of the method.Compared with the widely-used pock-chop plot method, the proposed method reduces the computational time by two orders of magnitude for the same search precision, and thus is especially suitable for the cases involving rapid, high-precision, and/or large-scale searches for mission opportunities.
基金the National Natural Science Foundation of China(No.U1610104)Liaoning Revitalization Talents Program(No.XLYC1907053,China)CAS Youth Innovation Promotion Association(No.2018220,China)。
文摘Dimethyl ether(DME),as a promising alternative to diesel fuel and liquefied petroleum gas,has attracted considerable attention in catalysis domain.The catalytic direct synthesis of DME from syngas is an upand-coming route but remains a challenge.In this work,we firstly prepared a Cu-embedded porous Al_(2)O_(3)bifunctional catalyst(Cu@Al_(2)O_(3)-dp)by filling Cu-1,3,5-benzenetricarboxylate metal–organic framework(Cu-BTC MOF)with Al(OH)_(3) followed by a two-step calcination process(400℃for 4 h and 600℃for1 h),exhibiting excellent catalytic performance for direct synthesis of DME from syngas.Cu@Al_(2)O_(3)-dp catalyst demonstrates much higher CO conversion(25.7%vs.15.4%)and extremely higher DME selectivity(90.4%vs.63.9%)with the increased catalytic stability compared to the supported Cu catalyst on MOF-derived porous Al_(2)O_(3)(Cu/Al_(2)O_(3))prepared by incipient wetness impregnation method,ascribed to the unique embedding-type structure,promoted Cu dispersion and stronger metal-support interaction.This work not only provides an efficient syngas-to-DME catalyst,but also paves a new way for designing highly-efficient core-shell bifunctional catalysts for diverse consecutive reactions.
基金supported by National Natural Science Foundation of China(no.21978030),and also sponsored by the Chinese Ministry of Education via the Program for New Century Excellent Talents in University(no.NCET-12-0079).
文摘Developing an efficientmethod to improve the photocatalytic efficiency of graphitic carbon nitride(g-C3 N4)is of great significance for solar H2 production.Electronic structure modulation has been considered one of the most crucial strategies to improving the photocatalytic efficiency of g-C_(3)N_(4),but how to efficiently modulate its electronic structure remains a huge challenge.Herein,we,for the first time,report a facile and highly-efficient approach to modulating the electronic structure of g-C_(3)N_(4)through single Ag atom implantation with a Ag_(1)-N_(3)coordination configuration into the g-C_(3)N_(4)framework.
