The catalytic conversion of ethane to high value-added chemicals is significantly important for utilization of hydrocarbon resources.However, it is a great challenge due to the typically required high temperature(>...The catalytic conversion of ethane to high value-added chemicals is significantly important for utilization of hydrocarbon resources.However, it is a great challenge due to the typically required high temperature(> 400 ℃) conditions.Herein, a highly active catalytic conversion process of ethane at room temperature(25 ℃) is reported on single iron atoms confined in graphene via the porphyrin-like N4-coordination structures.Combining with the operando time of flight mass spectrometer and density functional theory calculations, the reaction is identified as a radical mechanism, in which the C–H bonds of the same C atom are preferentially and sequentially activated, generating the value-added C2 chemicals, simultaneously avoiding the over-oxidation of the products to CO2.The in-situ formed O–FeN4–O structure at the single iron atom serves as the active center for the reaction and facilitates the formation of ethyl radicals.This work deepens the understanding of alkane C–H activation on the FeN4 center and provides the reference in development of efficient catalyst for selective oxidation of light alkane.展开更多
Nickel and potassium co-modified β-Mo2C catalysts were prepared and used for CO hydrogenation reaction. The major products over β-Mo2C were C1-C4 hydrocarbons, only few alcohols were obtained. Addition of potassium ...Nickel and potassium co-modified β-Mo2C catalysts were prepared and used for CO hydrogenation reaction. The major products over β-Mo2C were C1-C4 hydrocarbons, only few alcohols were obtained. Addition of potassium resulted in remarkable selectivity shift from hydrocarbons to alcohols at the expense of CO conversion over β-Mo2C. Moreover, it was found that potassium enhanced the ability of chain propagation with a higher C2＋OH production. Modified by nickel,β-Mo2C showed a relatively high CO conversion, however, the products were similar to those of pure β-Mo2C. When co-modified by nickel and potassium,β-Mo2C exhibited high activity and selectivity towards mixed alcohols synthesis, and also the whole chain propagation to produce alcohols especially for the stage of C1 OH to C2OH was remarkably enhanced. It was concluded that the Ni and K had, to some extent, synergistic effect on CO conversion.展开更多
Stimulated by increasing environmental awareness and renewable-energy utilization capabilities,fuel cell and electrolyzer technologies have emerged to play a unique role in energy storage,conversion,and utilization.In...Stimulated by increasing environmental awareness and renewable-energy utilization capabilities,fuel cell and electrolyzer technologies have emerged to play a unique role in energy storage,conversion,and utilization.In particular,solid oxide electrolysis cells(SOECs)are increasingly attracting the interest of researchers as a platform for the electrolysis and conversion of C1 molecules,such as carbon dioxide and methane.Compared to traditional catalysis methods,SOEC technology offers two major advantages:high energy efficiency and poisoning resistance,ensuring the long-term robustness of C1-to-fuels conversion.In this review,we focus on state-of-the-art technologies and introduce representative works on SOEC-based techniques for C1 molecule electrochemical conversion developed over the past several years,which can serve as a timely reference for designing suitable catalysts and cell processes for efficient and practical conversion of C1 molecules.The challenges and prospects are also discussed to suggest possible research directions for sustainable fuel production from C1 molecules by SOECs in the near future.展开更多
Converting solar energy into valuable hydrogen and hydrocarbon fuels through photoelectrocatalytic water splitting and CO2 reduction is highly promising in addressing the growing demand for renewable and clean energy ...Converting solar energy into valuable hydrogen and hydrocarbon fuels through photoelectrocatalytic water splitting and CO2 reduction is highly promising in addressing the growing demand for renewable and clean energy resources. However, the solar-to-fuel conversion efficiency is still very low due to limited light absorption and rapid bulk recombination of charge carriers. In this work, we present chlorophyll （Chl） and its derivative sodium copper chlorophyllin （ChlCuNa）, as dye sensitizers, modified BiVO4 to improve the photoelectrochemical （PEC） performance. The photocurrent of BiVO4 is surprisingly decreased after a direct sensitization of Chl while the sensitization of ChlCuNa obviously enhances photocurrent of BiV04 electrodes by improved surface hydrophilicity and extended light absorption. ChlCuNa-sensitized BiVO4 achieves an improved H2 evolution rate of 5.43/~molh l cm 2 in water splitting and an enhanced HCOOH production rate 0f2.15 p^mol h 1 cm 2 in CO2 PEC reduction, which are 1.9 times and 2.4 times higher than pristine BiV04, respectively. It is suggested that the derivative ChlCuNa is a more effective sensitizer for solar-to-fuel energy conversion and CO2 utilization than Chl.展开更多
Extensive research has been devoted to lithium-sulfur(Li-S)batteries due to their overwhelming promises and advantages such as high theoretical capacity(1675 m Ah g^(-1)),extremely cost effectiveness and abundance and...Extensive research has been devoted to lithium-sulfur(Li-S)batteries due to their overwhelming promises and advantages such as high theoretical capacity(1675 m Ah g^(-1)),extremely cost effectiveness and abundance and availability of sulfur.Nevertheless,a sluggish electrochemical kinetics of the battery limited by a slow conversion of lithium polysulfide(LiPSs)intermediates and Li PSs shuttle effect severely hinder its development towards industrial application.Herein,we designed the oxidized Nb2_(C)MXene with amorphous carbon(Nb_(2)O_(5)/C)composites as sulfur host using CO_(2)treatment to address the above issues.The Nb_(2)O_(5)/C composites with high conductivity are directly employed as sulfur hosts for Li-S battery capable to remarkably mitigate the shuttle phenomenon due to a combined effect of their Li PSs trapping ability and catalytic activity towards their accelerated conversion.Meanwhile,the unique layered structure of the composite facilitates ion transfer and accommodates the volume changes of the cathode during cycling.With this rational design,the resultant Li-S batteries exhibit superior electrochemical performance with a high initial specific capacity of 745 m Ah g^(-1)at 1.0 C and a reversible capacity of 620 m Ah g^(-1)at a high rate cycling at 3.0 C.展开更多
Engineering non-precious metals into nitrogen-doped carbon is employed to improve electrocatalyst activity towards oxygen reduction reaction(ORR). A nickel-doped Co-N/C mesoporous nanopolyhedron is successfully evolut...Engineering non-precious metals into nitrogen-doped carbon is employed to improve electrocatalyst activity towards oxygen reduction reaction(ORR). A nickel-doped Co-N/C mesoporous nanopolyhedron is successfully evoluted from a Ni-doped ZIF-67 precursor. The Ni & Co synergistic N/C catalyst exhibits a half-wave potential of 0.895 V(vs. reversible hydrogen electrode(RHE)) with a diffusion-limiting current density of 6.1 m A cm^(-2)for alkaline ORR at 1600 r min^(-1), which is competitive to commercial Pt/C in terms of cost, methanol tolerance, and long-term stability. In situ surface-enhanced Raman scattering(SERS) study reveals the formation and fast conversion of superoxide ion(O_(2)^(-)) intermediate on the catalyst surface. Density functional theory(DFT) calculations demonstrate the decrease of energy barrier for potential-determining step(O* protonation) by Co-Ni synergy as well as the reduction of adsorption energy on catalyst surface upon nickel doping. The joint results of in situ SERS study and DFT calculations suggest a favourable ORR process on nickel-doped Co-N/C.展开更多
MXene,a new type of two-dimensional materials,have been demonstrated as one of the best photothermal materials owing to their strong light-matter interaction and high photothermal conversion efficiency in recent years...MXene,a new type of two-dimensional materials,have been demonstrated as one of the best photothermal materials owing to their strong light-matter interaction and high photothermal conversion efficiency in recent years.Herein,we report the intriguing light-to-heat conversion property of vanadium carbide(V_(2)C)MXene under irradiation of millisecond laser pulse.Unlike the typical photothermal materials,the V_(2)C MXene not only converts the incident laser energy to heat by the physical photothermal effect,but also triggers the exothermic oxidation of the V_(2)C MXene.The oxidation could be greatly promoted with addition of plasmonic Au nanorods(Au NRs)for light absorption enhancement.Owing to the unique light-to-heat conversion property,the Au NRs/V_(2)C MXene membrane could serve as high temperature pulse(HTP)generators that is proposed for numerous applications with high demand for immediacy.As a proof-of concept application,Au NRs/V_(2)C MXene membrane was applied for laser ignition of the high energy density materials,such as 2,4,6,8,10,12-(hexanitrohexaaza)cyclododecane(HNIW or CL-20).An improved ignition performance,in terms of lowered laser threshold,is achieved as compared to the state-of-the-art light-to-heat conversion materials.展开更多
This study investigates the effects of addition of oxygen on the oxidative dehydrogenation （ODH） of methanol when a fluorotetrasilicic mica ion-exchanged with palladium （Pd2^＋-TSM） was used as the catalyst. The r...This study investigates the effects of addition of oxygen on the oxidative dehydrogenation （ODH） of methanol when a fluorotetrasilicic mica ion-exchanged with palladium （Pd2^＋-TSM） was used as the catalyst. The reaction proceeded at a very low temperature in the presence of oxygen, and HCOOCH3 was obtained at high selectivity. By calculating the equilibrium conversion, it has been shown that substantial ODH took place for HCOOCH3 production. Consequently, this reaction would make dehydrogenation the dominant reaction at equilibrium. Not all the H dissociated from CH3OH was converted to H20 by oxidation. It has been shown that the H2O was not produced from oxidative dehydrogenation by the direct reaction of CH3OH and O2 when an attempt was made to carry out oxidative dehydrogenation using an isotope oxygen trace method in the gas phase. Therefore, when CHaOH was converted to CO2 and dehydrogenated to HCOOCH3, the C-O bonds were not dissociated.展开更多
A new self-assembled monolayer (SAM) of fullerene derivative has been fabricated and their photoelectric conversion property has been observed. The SAM was fabricated on indium-tin-oxide (ITO) and quartz by amide bond...A new self-assembled monolayer (SAM) of fullerene derivative has been fabricated and their photoelectric conversion property has been observed. The SAM was fabricated on indium-tin-oxide (ITO) and quartz by amide bonding. It was characterized bq contact angle, UV spectrum. and cyclic voltammetry. The mild fabrication conditions and the stability of the SAM provides a way to build three-dimensional structure more easily.展开更多
Conversion refers to the transformation of parts of speech in some words while maintaining the original content unchanged in order to make the translated text sound smooth and fluent as well as more idiomatic in the t...Conversion refers to the transformation of parts of speech in some words while maintaining the original content unchanged in order to make the translated text sound smooth and fluent as well as more idiomatic in the target language. In E-C translation, conversion of pars of speech is one of the most important translation methods. Several different forms about conversion of parts of speech are introduced through analyzing the differences and usages between the two languages so that a better version in E-C translation can be got.展开更多
The efficient limitation of the"shuttle effect"of polysulfide from the rational construction of electrocatalysts to accelerate the redox kinetics of polysulfides is extremely important.In this work,the cobal...The efficient limitation of the"shuttle effect"of polysulfide from the rational construction of electrocatalysts to accelerate the redox kinetics of polysulfides is extremely important.In this work,the cobalt/Nickel bimetallic alloy polyhedrons decorated on layered TiO_(2)heterostructure(Co Ni@TiO_(2)/C)derived from MXene and bimetallic metal-organic framework have been prepared through liquid-phase deposition and high-temperature annealing processes.This heterostructure presents excellent electrical conductivity,which facilitates ion diffusion and electron transfer within the battery.Besides,the heterostructure from anchoring the Co Ni bimetallic alloy on the layered TiO_(2)ensures the full exposure of active sites and accelerates polysulfide redox kinetics through chemisorption and catalytic conversion.Considering these advantages mentioned above,when applied as the lithium-sulfur batteries(LSBs)separator modifier,the cell assembled from the Co Ni@TiO_(2)/C modified separator demonstrates high specific capacity(1481.7 mAh/g at 0.5 C),superior rate capability(855.5 mAh/g at 3 C)and excellent cycling performance,which can maintain the high capacity of 856.09 mAh/g after 300 cycles with low capacity decay rate of 0.09%per cycle.Even under a high sulfur loading of 4.4 mg/cm^(2),the cell can still present excellent cycling stability.This study paves the way for the design of novel material for the construction of an outstanding functional separator layer and shines the light on the effective and feasible way for the inhibition of shuttle effect in lithium-sulfur batteries.展开更多
基金the financial support from the Ministry of Science and Technology of China (Nos.2016YFA0204100 and 2016YFA0200200)the National Natural Science Foundation of China (Nos.21890753, 21573220 and 21802124)+2 种基金the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences (No.QYZDB-SSW-JSC020)the DNL Cooperation Fund, CAS (No.DNL180201)the financial and technique supports from the Westlake Education Foundation, Supercomputing Systems in the Information Technology Center of Westlake University
文摘The catalytic conversion of ethane to high value-added chemicals is significantly important for utilization of hydrocarbon resources.However, it is a great challenge due to the typically required high temperature(> 400 ℃) conditions.Herein, a highly active catalytic conversion process of ethane at room temperature(25 ℃) is reported on single iron atoms confined in graphene via the porphyrin-like N4-coordination structures.Combining with the operando time of flight mass spectrometer and density functional theory calculations, the reaction is identified as a radical mechanism, in which the C–H bonds of the same C atom are preferentially and sequentially activated, generating the value-added C2 chemicals, simultaneously avoiding the over-oxidation of the products to CO2.The in-situ formed O–FeN4–O structure at the single iron atom serves as the active center for the reaction and facilitates the formation of ethyl radicals.This work deepens the understanding of alkane C–H activation on the FeN4 center and provides the reference in development of efficient catalyst for selective oxidation of light alkane.
基金supported by the National Key Project for Basic Research of China (973 Project) (No. 2005CB221400)
文摘Nickel and potassium co-modified β-Mo2C catalysts were prepared and used for CO hydrogenation reaction. The major products over β-Mo2C were C1-C4 hydrocarbons, only few alcohols were obtained. Addition of potassium resulted in remarkable selectivity shift from hydrocarbons to alcohols at the expense of CO conversion over β-Mo2C. Moreover, it was found that potassium enhanced the ability of chain propagation with a higher C2＋OH production. Modified by nickel,β-Mo2C showed a relatively high CO conversion, however, the products were similar to those of pure β-Mo2C. When co-modified by nickel and potassium,β-Mo2C exhibited high activity and selectivity towards mixed alcohols synthesis, and also the whole chain propagation to produce alcohols especially for the stage of C1 OH to C2OH was remarkably enhanced. It was concluded that the Ni and K had, to some extent, synergistic effect on CO conversion.
文摘Stimulated by increasing environmental awareness and renewable-energy utilization capabilities,fuel cell and electrolyzer technologies have emerged to play a unique role in energy storage,conversion,and utilization.In particular,solid oxide electrolysis cells(SOECs)are increasingly attracting the interest of researchers as a platform for the electrolysis and conversion of C1 molecules,such as carbon dioxide and methane.Compared to traditional catalysis methods,SOEC technology offers two major advantages:high energy efficiency and poisoning resistance,ensuring the long-term robustness of C1-to-fuels conversion.In this review,we focus on state-of-the-art technologies and introduce representative works on SOEC-based techniques for C1 molecule electrochemical conversion developed over the past several years,which can serve as a timely reference for designing suitable catalysts and cell processes for efficient and practical conversion of C1 molecules.The challenges and prospects are also discussed to suggest possible research directions for sustainable fuel production from C1 molecules by SOECs in the near future.
基金financial support from Ministry of Science and Technology of the People’s Republic of China(No.2016YFE0112200)the National Natural Science Foundation of China(Nos.21507011,21677037,21607027)
文摘Converting solar energy into valuable hydrogen and hydrocarbon fuels through photoelectrocatalytic water splitting and CO2 reduction is highly promising in addressing the growing demand for renewable and clean energy resources. However, the solar-to-fuel conversion efficiency is still very low due to limited light absorption and rapid bulk recombination of charge carriers. In this work, we present chlorophyll （Chl） and its derivative sodium copper chlorophyllin （ChlCuNa）, as dye sensitizers, modified BiVO4 to improve the photoelectrochemical （PEC） performance. The photocurrent of BiVO4 is surprisingly decreased after a direct sensitization of Chl while the sensitization of ChlCuNa obviously enhances photocurrent of BiV04 electrodes by improved surface hydrophilicity and extended light absorption. ChlCuNa-sensitized BiVO4 achieves an improved H2 evolution rate of 5.43/~molh l cm 2 in water splitting and an enhanced HCOOH production rate 0f2.15 p^mol h 1 cm 2 in CO2 PEC reduction, which are 1.9 times and 2.4 times higher than pristine BiV04, respectively. It is suggested that the derivative ChlCuNa is a more effective sensitizer for solar-to-fuel energy conversion and CO2 utilization than Chl.
基金supported by Natural Science Foundation of Hebei Province of China(Nos.B2021202028,B2020202052,B2019202277)Outstanding Youth Project of Guangdong Natural Science Foundation(No.2021B1515020051)+9 种基金State Key Laboratory of Reliability and Intelligence of Electrical Equipment(No.EERI_PI2020007)Hebei University of Technology,Chinathe Program for the Outstanding Young Talents of Hebei Province,China(YG.Z.)Chunhui Project of Ministry of Education of the People’s Republic of China(No.Z2017010)Department of Science and Technology of Guangdong Province(Nos.2020B0909030004,2019JC01L203)Guangdong Innovative and Entrepreneurial Team Program(No.2016ZT06C517)Science and Technology Program of Guangzhou(No.2019050001)Science and Technology Program of Zhaoqing(No.2019K038)project AP09259764“Engineering of Multifunctional Materials of Next Generation Batteries”from the Ministry of Education and Science of Kazakhstana research project FDCRP No.110119FD4504“Development of 3D solid state thin film materials for durable and safe Li-ion microbatteries”from Nazarbayev University。
文摘Extensive research has been devoted to lithium-sulfur(Li-S)batteries due to their overwhelming promises and advantages such as high theoretical capacity(1675 m Ah g^(-1)),extremely cost effectiveness and abundance and availability of sulfur.Nevertheless,a sluggish electrochemical kinetics of the battery limited by a slow conversion of lithium polysulfide(LiPSs)intermediates and Li PSs shuttle effect severely hinder its development towards industrial application.Herein,we designed the oxidized Nb2_(C)MXene with amorphous carbon(Nb_(2)O_(5)/C)composites as sulfur host using CO_(2)treatment to address the above issues.The Nb_(2)O_(5)/C composites with high conductivity are directly employed as sulfur hosts for Li-S battery capable to remarkably mitigate the shuttle phenomenon due to a combined effect of their Li PSs trapping ability and catalytic activity towards their accelerated conversion.Meanwhile,the unique layered structure of the composite facilitates ion transfer and accommodates the volume changes of the cathode during cycling.With this rational design,the resultant Li-S batteries exhibit superior electrochemical performance with a high initial specific capacity of 745 m Ah g^(-1)at 1.0 C and a reversible capacity of 620 m Ah g^(-1)at a high rate cycling at 3.0 C.
基金supported by the National Natural Science Foundation of China (No. 21874053)the Science and Technology Development Project of Jilin Province, China (No. 20180414022GH)funding from the Advanced Low Carbon Technology Research and Development Program (ALCA), specially promoted research for innovative nextgeneration batteries (SPRING)。
文摘Engineering non-precious metals into nitrogen-doped carbon is employed to improve electrocatalyst activity towards oxygen reduction reaction(ORR). A nickel-doped Co-N/C mesoporous nanopolyhedron is successfully evoluted from a Ni-doped ZIF-67 precursor. The Ni & Co synergistic N/C catalyst exhibits a half-wave potential of 0.895 V(vs. reversible hydrogen electrode(RHE)) with a diffusion-limiting current density of 6.1 m A cm^(-2)for alkaline ORR at 1600 r min^(-1), which is competitive to commercial Pt/C in terms of cost, methanol tolerance, and long-term stability. In situ surface-enhanced Raman scattering(SERS) study reveals the formation and fast conversion of superoxide ion(O_(2)^(-)) intermediate on the catalyst surface. Density functional theory(DFT) calculations demonstrate the decrease of energy barrier for potential-determining step(O* protonation) by Co-Ni synergy as well as the reduction of adsorption energy on catalyst surface upon nickel doping. The joint results of in situ SERS study and DFT calculations suggest a favourable ORR process on nickel-doped Co-N/C.
基金the National Natural Science Foundation of China (21703217, 11702264, 11702268, 11802276, 11772307) for financial support
文摘MXene,a new type of two-dimensional materials,have been demonstrated as one of the best photothermal materials owing to their strong light-matter interaction and high photothermal conversion efficiency in recent years.Herein,we report the intriguing light-to-heat conversion property of vanadium carbide(V_(2)C)MXene under irradiation of millisecond laser pulse.Unlike the typical photothermal materials,the V_(2)C MXene not only converts the incident laser energy to heat by the physical photothermal effect,but also triggers the exothermic oxidation of the V_(2)C MXene.The oxidation could be greatly promoted with addition of plasmonic Au nanorods(Au NRs)for light absorption enhancement.Owing to the unique light-to-heat conversion property,the Au NRs/V_(2)C MXene membrane could serve as high temperature pulse(HTP)generators that is proposed for numerous applications with high demand for immediacy.As a proof-of concept application,Au NRs/V_(2)C MXene membrane was applied for laser ignition of the high energy density materials,such as 2,4,6,8,10,12-(hexanitrohexaaza)cyclododecane(HNIW or CL-20).An improved ignition performance,in terms of lowered laser threshold,is achieved as compared to the state-of-the-art light-to-heat conversion materials.
文摘This study investigates the effects of addition of oxygen on the oxidative dehydrogenation （ODH） of methanol when a fluorotetrasilicic mica ion-exchanged with palladium （Pd2^＋-TSM） was used as the catalyst. The reaction proceeded at a very low temperature in the presence of oxygen, and HCOOCH3 was obtained at high selectivity. By calculating the equilibrium conversion, it has been shown that substantial ODH took place for HCOOCH3 production. Consequently, this reaction would make dehydrogenation the dominant reaction at equilibrium. Not all the H dissociated from CH3OH was converted to H20 by oxidation. It has been shown that the H2O was not produced from oxidative dehydrogenation by the direct reaction of CH3OH and O2 when an attempt was made to carry out oxidative dehydrogenation using an isotope oxygen trace method in the gas phase. Therefore, when CHaOH was converted to CO2 and dehydrogenated to HCOOCH3, the C-O bonds were not dissociated.
文摘A new self-assembled monolayer (SAM) of fullerene derivative has been fabricated and their photoelectric conversion property has been observed. The SAM was fabricated on indium-tin-oxide (ITO) and quartz by amide bonding. It was characterized bq contact angle, UV spectrum. and cyclic voltammetry. The mild fabrication conditions and the stability of the SAM provides a way to build three-dimensional structure more easily.
文摘Conversion refers to the transformation of parts of speech in some words while maintaining the original content unchanged in order to make the translated text sound smooth and fluent as well as more idiomatic in the target language. In E-C translation, conversion of pars of speech is one of the most important translation methods. Several different forms about conversion of parts of speech are introduced through analyzing the differences and usages between the two languages so that a better version in E-C translation can be got.
基金supported by National Natural Science Foundation of China(Nos.52472194,52101243)Natural Science Foundation of Guangdong Province,China(No.2023A1515012619)the Science and Technology Planning Project of Guangzhou(No.202201010565)。
文摘The efficient limitation of the"shuttle effect"of polysulfide from the rational construction of electrocatalysts to accelerate the redox kinetics of polysulfides is extremely important.In this work,the cobalt/Nickel bimetallic alloy polyhedrons decorated on layered TiO_(2)heterostructure(Co Ni@TiO_(2)/C)derived from MXene and bimetallic metal-organic framework have been prepared through liquid-phase deposition and high-temperature annealing processes.This heterostructure presents excellent electrical conductivity,which facilitates ion diffusion and electron transfer within the battery.Besides,the heterostructure from anchoring the Co Ni bimetallic alloy on the layered TiO_(2)ensures the full exposure of active sites and accelerates polysulfide redox kinetics through chemisorption and catalytic conversion.Considering these advantages mentioned above,when applied as the lithium-sulfur batteries(LSBs)separator modifier,the cell assembled from the Co Ni@TiO_(2)/C modified separator demonstrates high specific capacity(1481.7 mAh/g at 0.5 C),superior rate capability(855.5 mAh/g at 3 C)and excellent cycling performance,which can maintain the high capacity of 856.09 mAh/g after 300 cycles with low capacity decay rate of 0.09%per cycle.Even under a high sulfur loading of 4.4 mg/cm^(2),the cell can still present excellent cycling stability.This study paves the way for the design of novel material for the construction of an outstanding functional separator layer and shines the light on the effective and feasible way for the inhibition of shuttle effect in lithium-sulfur batteries.
