The autothermic pyrolysis in-situ conversion process (ATS) consumes latent heat of residual organic matter after kerogen pyrolysis by oxidation reaction, and it has the advantages of low development cost and exploitat...The autothermic pyrolysis in-situ conversion process (ATS) consumes latent heat of residual organic matter after kerogen pyrolysis by oxidation reaction, and it has the advantages of low development cost and exploitation of deep oil shale resources. However, the heating mechanism and the characteristic of different reaction zones are still unclear. In this study, an ATS numerical simulation model was proposed for the development of oil shale, which considers the pyrolysis of kerogen, high-temperature oxidation, and low-temperature oxidation. Based on the above model, the mechanism of the ATS was analyzed and the effects of preheating temperature, O_(2) content, and injection rate on recovery factor and energy efficiency were studied. The results showed that the ATS in the formation can be divided into five characteristic zones by evolution of the oil and O_(2) distribution, and the solid organic matter, including residue zone, autothermic zone, pyrolysis zone, preheating zone, and original zone. Energy efficiency was much higher for the ATS than for the high-temperature nitrogen injection in-situ conversion process (HNICP). There is a threshold value of the preheating temperature, the oil content, and the injection rate during the ATS, which is 400 °C, 0.18, and 1100 m3/day, respectively, in this study.展开更多
The aligned molecular packing structure is vital to the anisotropic charge transport in conjugated polymer and small molecule thin films.However,how this molecular packing motif influences the photoelectric conversion...The aligned molecular packing structure is vital to the anisotropic charge transport in conjugated polymer and small molecule thin films.However,how this molecular packing motif influences the photoelectric conversion process at the donor/acceptor heterojunction is still mysterious.Herein,we employed a PM6/Y6 bilayer model to investigate the long-range alignment of molecular packing induced photoelectric conversion process.Both PM6 and Y6 layers were properly controlled to exhibit the uniaxially oriented molecular packing compared to their as-cast counterparts,as revealed by the polarized absorption spectra and transmission electron microscopy.After analyzing the photovoltaic performance of bilayer devices,the smaller energy loss,lower energetic disorder,and longer charge carrier lifetime can be observed in the bilayer devices with aligned Y6 molecules,which contribute to a higher power conversion efficiency(PCE)than the as-cast devices.While the molecular packing structure of PM6 layer exhibited negligible influence on the device performance,probably resulting from the intrinsic semicrystalline nature of PM6 molecules.Our results indicate that the alignment of small molecular acceptor at the donor/acceptor interfaces should be a powerful strategy to facilitate the photoelectric conversion process,which will definitely pave the way to highly efficient bulk heterojunction photovoltaic device.展开更多
Simulation of thermal-reactive-compositional flow processes is fundamental to the thermal recovery of ultra-heavy hydrocarbon resources,and a typical oilfield practice is the in-situ conversion process(ICP)implemented...Simulation of thermal-reactive-compositional flow processes is fundamental to the thermal recovery of ultra-heavy hydrocarbon resources,and a typical oilfield practice is the in-situ conversion process(ICP)implemented in oil shale exploitation.However,accurately capturing the intricate flow dynamics of ICP requires a large number of fine-scale grid-blocks,which renders ICP simulations computationally expensive.Apart from that,plenty of oil shale reservoirs contain natural fractures or require hydraulic fracturing to enhance fluid mobility,creating further challenges in modeling pyrolysis reactions in both rock matrices and fractures.Targeted at the above issues,this work proposes a novel dual-model dualgrid upscaling(DDU)method specifically designed for solid-based thermal-reactive-compositional flow simulations in fractured porous media.Unlike existing upscaling techniques,the DDU method incorporates the upscaling of fracture grids using the embedded discrete fracture modeling(EDFM)approach and introduces a new concept of simplified models to approximate fine-scale results,which are used to correct reaction rates in coarse-scale grids.This method uniquely achieves efficient upscaling for both matrix and fracture grids,supports both open-source and commercial simulation platforms without modifying source codes,and is validated through 3D ICP models with natural fractures.The results indicate that the application of the DDU method can provide a close match with the fine-scale simulation results.Moreover,the DDU method has drastically improved the computational efficiency and speeded up the fine-scale simulation by 396-963 times.Therefore,the proposed DDU method has achieved marked computational savings while maintaining high simulation accuracy,which is significant for the development efficiency and production forecasting of oil shale reservoirs.展开更多
The purpose of this study is to investigate the entire evolution process of shales with various total organic contents(TOC)in order to build models for quantitative evaluation of oil and gas yields and establish metho...The purpose of this study is to investigate the entire evolution process of shales with various total organic contents(TOC)in order to build models for quantitative evaluation of oil and gas yields and establish methods for assessing recoverable oil and gas resources from in-situ conversion of organic matters in shale.Thermal simulation experiments under in-situ conversion conditions were conducted on Chang 7_(3) shales from the Ordos Basin in a semi-open system with large capacity.The results showed that TOC and R_(o) were the key factors affecting the in-situ transformation potential of shale.The remaining oil and gas yields increased linearly with TOC but inconsistently with R_(o).R_(o) ranged 0.75%—1.25%and 1.05%—2.3%,respectively,corresponding to the main oil generation stage and gas generation stage of shale in-situ transformation.Thus a model to evaluate the remaining oil/gas yield with TOC and R_(o) was obtained.The TOC of shale suitable for in-situ conversion should be greater than 6%,whereas its R_(o) should be less than 1.0%.Shales with 0.75%(R_(o))could obtain the best economic benefit.The results provided a theoretical basis and evaluation methodology for predicting the hydrocarbon resources from in-situ conversion of shale and for the identification of the optimum“sweet spots”.The assessment of the Chang 7_(3) shale in the Ordos Basin indicated that the recoverable oil and gas resources from in-situ conversion of organic matters in shale are substantial,with oil and gas resources reaching approximately 450×10^(8) t and 30×10^(12)m^(3),respectively,from an area of 4.27×10^(4) km^(2).展开更多
Tunable coherent emission is generated in a single-pass, cascaded wavelength conversion process from mode-locked laser-pumped monolithic periodically poled lithium niobate（PPLN）. Three ranges of wavelength, includin...Tunable coherent emission is generated in a single-pass, cascaded wavelength conversion process from mode-locked laser-pumped monolithic periodically poled lithium niobate（PPLN）. Three ranges of wavelength, including visible output from 628 nm to 639 nm, near-infrared output from 797 nm to 816 nm, and mid-infrared output from 3167 nm to 3459 nm,were obtained from the monolithic PPLN, which consists of a 10-mm section for 532-nm-pumped optical parametric generation（OPG） and a 7-mm section for 1064-nm-pumped sum frequency generation（SFG）. A pump-to-signal conversion efficiency of 23.4% for OPG at 50°C and a quantum efficiency of 26.2% for SFG at 200°C were obtained.展开更多
MoS_(2) is a highly promising material for application in lithium-ion battery anodes due to its high theoretical capacity and low cost.However,problems with a fast capacity decay over cycling,especially at the first c...MoS_(2) is a highly promising material for application in lithium-ion battery anodes due to its high theoretical capacity and low cost.However,problems with a fast capacity decay over cycling,especially at the first cycles,and poor rate performance have deterred its practical implementation.Herein,electrodes comprised solely of few-layers 2D MoS_(2) nanosheets have been manufactured by scalable liquid-phase exfoliation and spray deposition methods.The long-standing controversy questioning the reversibility of conversion processes of MoS_(2)-based electrodes was addressed.Raman studies revealed that,in 2D MoS_(2) electrodes,conversion processes are indeed reversible,where nanostructure played a key role.Cycling of the electrodes at high current rates revealed an intriguing phenomenon consisting of a continuously increasing capacity after ca.100-200 cycles.This phenomenon was comprehensively addressed by a variety of electrochemical and microscopy methods that revealed underlying physical activation mechanisms that involved a range of profound electrode structural changes.Activation mechanisms delivered a capacitive electrode of a superior rate performance and cycling stability,as compared to the corresponding pristine electrodes,and to MoS_(2) electrodes previously reported.Herein,we have devised a methodology to overcome the problem of cycling stability of 2D MoS_(2) electrodes.Moreover,activation of electrodes constitutes a methodology that could be applied to enhance the energy storage performance of electrodes based on other 2D nanomaterials,or combinations thereof,strategically combining chemistries to engineer electrodes of superior energy storage properties.展开更多
In the suburbs of Kitakyushu,Japan,the inorganic aerosol mass concentration(IAM)was about 32.7μg/m^(3),with the aerosol pH of 3.3.To study the thermodynamics of aerosol when its individual components'concentratio...In the suburbs of Kitakyushu,Japan,the inorganic aerosol mass concentration(IAM)was about 32.7μg/m^(3),with the aerosol pH of 3.3.To study the thermodynamics of aerosol when its individual components'concentration is reduced,sensitive tests were performed using the ISORROPIAⅡmodel,in which the seven control species—TNaCl,TNH_(4)^(+),TSO_(4)^(2-),TNO_(3)^(-),TMg^(2+),TK^(+),and TCa^(2+)—were taken into account.IAM and inorganic aerosol pH after reducing TNaCl,TNO_(3)^(-),TMg^(2+),TK^(+),and TCa^(2+)responded linearly(0%≤concentration reduction ratio(CRR)≤100%,with the exception of 100%in TNaCl);the nonlinear variations of these two parameters could be observed by controlling TNH_(4)^(+)and TSO_(4)^(2-).Unexpected aerosol behavior occurred at 100%reduction of TNaCl,which was caused by the sudden increase of NO_(3)^(-),NH_(4)^(+),and aerosol liquid water content(ALWC);the increase of IAM was also observed after controlling TSO_(4)^(2-)(60%≤CRR≤100%)and TCa^(2+)(0%≤CRR≤100%),which was mainly related to the variation of ALWC driven by the response of CaSO_(4).Multiple regression analysis showed that ALWC was statistically and strongly related to the variations of NO_(3)^(-),Cl-,SO_(4)^(2-),HSO_(4)^(-),HNO_(3),and NH_(3)(P<0.05),with regression coefficients of 1.68,5.23,1.83,2.81,0.34,and 0.57,respectively.The highest coefficient(5.23)was found for Cl^(-),revealing that sea salts significantly influenced particle responses.Overall,this study comprehensively investigated aerosol characteristics and inner responses for the reduction of components,which is of great significance for a better understanding of atmospheric chemistry in Kitakyushu,Japan.展开更多
In contrast to marine deposits, continental deposits in China are characterized by diverse sedimentary types, rapid changes in sedimentary facies, complex lithology, and thin, small sand bodies. In seismic sedimentolo...In contrast to marine deposits, continental deposits in China are characterized by diverse sedimentary types, rapid changes in sedimentary facies, complex lithology, and thin, small sand bodies. In seismic sedimentology studies on continental lacustrine basins, new thinking and more detailed and effective technical means are needed to generate lithological data cubes and conduct seismic geo- morphologic analyses. Based on a series of tests and studies, this paper presents the concepts of time-equivalent seismic attributes and seismic sedimentary bodies and a ＂four-step approach＂ for the seismic sedimentologic study of conti- nental basins： Step 1, build a time-equivalent stratigraphic framework based on vertical analysis and horizontal corre- lation of lithofacies, electrofacies, seismic facies, and pale- ontological combinations; Step 2, further build a sedimentary facies model based on the analysis of single- well facies with outcrop, coring, and lab test data; Step 3, convert the seismic data into a lithological data cube reflecting different lithologies by means of seismic tech- niques; and Step 4, perform a time-equivalent attribute analysis and convert the planar attribute into a sedimentary facies map under the guidance of the sedimentary facies model. The whole process, highlighting the verification and calibration of geological data, is an iteration and feedback procedure of geoseismic data. The key technologies include the following： （1） a seismic data-lithology conversion technique applicable to complex lithology, which can convert the seismic reflection from interface types to rock layers; and （2） time-equivalent seismic unit analysis and a time- equivalent seismic attribute extraction technique. Finally, this paper demonstrates the validity of the approach with an example from the Qikou Sag in the Bohai Bay Basin and subsequent drilling results.展开更多
Despite the long tradition of fossil carbon(coal,char,and related carbon-based materials)for fueling mankind,the science of transforming them into chemicals is still demandingly progressing in the current energy scena...Despite the long tradition of fossil carbon(coal,char,and related carbon-based materials)for fueling mankind,the science of transforming them into chemicals is still demandingly progressing in the current energy scenario,especially when considering its responsibilities to the global climate change.Traditionally,there are four routes of preparing chemicals directly from fossil carbon,including hydrogasification,gasification,direct liquefaction,and oxidation,in the macroscope of gas-solid reaction(hydrogasification and gasification)and liquid-solid reaction(direct liquefaction and oxidation).When the study goes to microscale,the gas-solid reaction can be considered as the reaction between the severe condensed radicals and gas,while the liquid-solid reaction is the direct reaction between the radical and the activated-molecule.To have a full overview of the area,this review systematically summarizes the main factors in these processes and shows our own perspectives as follows,(ⅰ)stabilizing the free radicals generated from coal and then directly converting them has the highest efficiency in coal utilization;(ⅱ)the research on the self-catalytic process of coal structure will have a profound impact on the direct preparation of chemicals from fossil carbon.Further discussions are also proposed to guide the future study of the area into a more sustainable direction.展开更多
The effect of thiourea(TU) on the nickel deposition process was analyzed by means of linear-sweep voltammetry. Raman spectroscopy and infrared reflectance spectroscopy were used to investigate the adsorption of TU and...The effect of thiourea(TU) on the nickel deposition process was analyzed by means of linear-sweep voltammetry. Raman spectroscopy and infrared reflectance spectroscopy were used to investigate the adsorption of TU and the formation of nickel-TU complexes on copper surface. The experimental results indicate that the nucleation and the preceding conversion step are involved in the deposition of nickel on copper electrodes. TU makes the onset nucleation potential negative due to the formation of nickel-TU complexes, which can accelerate the nickel deposition. Moreover, the S atom in the TU molecule adsorbed on copper surface facilitates the coordination of TU to Ni 2+ . Meanwhile, TU might be adsorbed at a flatter orientation if no Ni 2+ is on the surface, while at a perpendicular orientation when Ni 2+ is coadsorbed.展开更多
Semiconductor metal oxides with narrow bandgap have emerged as a promising platform for photoelectrochemical reactions,yet their photoelectron-induced photocorrosion effect has been a limitation for their wider applic...Semiconductor metal oxides with narrow bandgap have emerged as a promising platform for photoelectrochemical reactions,yet their photoelectron-induced photocorrosion effect has been a limitation for their wider applications.Understanding the conversion processes concomitant with photoelectrochemical reaction at the electrode-electrolyte interface plays a crucial role in revealing the corrosion mechanisms and advancing the development of efficient photocathodes.However,accurately and in situ tracking these dynamic chemical events remains a great challenge due to the fact that reaction processes occur at nanoscale interfaces.Here,we track the electrochemical growth and conversion of copper nanostructures at interface by the evanescent field of the surface plasmon wave by using a gold-coated optical fiber as an electrochemical electrode and light sensing probe.The results exhibit correlation between redox processes of copper species and plasmonic resonances.Furthermore,in situ fiber-optic detection reveals the photocorrosion dynamics under photoelectrochemical reaction,including photoelectron-induced self-reduction of copper oxide and self-oxidation of cuprous oxide.These demonstrations facilitate not only the diagnosis for the health condition of photocathode nanomaterial,but also the understanding of the underlying reaction mechanism,and thus are potentially crucial for advancing the development of highly efficient photocathodes in future energy applications.展开更多
Microalgae have piqued renewed interest as a sustainable biofuel feedstock owing to their high CO_(2)conversion efficiency.However,the major limitation of microalga-based biofuel production is low productivity.In this...Microalgae have piqued renewed interest as a sustainable biofuel feedstock owing to their high CO_(2)conversion efficiency.However,the major limitation of microalga-based biofuel production is low productivity.In this study,CO_(2)in flue gas emitted from the coal-fired power plants was fixed through mass microalgal cultivation using only sunlight as an energy source.To minimize the cost and energy required to supply the flue gas and efficiently utilize the microalgal biomass,a polycarbonate(PC)greenhouse and polymeric photobioreactors were installed near the power plant stack.Four different microalgal strains(Chlamydomonas reinhardtii,Chlorella sorokiniana,Neochloris oleoabundans,and Neochloris oleoabundans#13)were subjected to semi-continuous culturing for 1 month.The maximum biomass productivity was achieved by the N.oleoabun-dans#13 strain(0.703 g L^(−1)day^(−1)).Additionally,polymerase chain reaction analysis revealed that the individual microalgal culture was not cross-contaminated with other microalgal cultures in this cultivation system,owing to the structural proper-ties of photobioreactor comprising individual modules.The lipid content and calorific productivity of N.oleoabundans#13 biomass were 45.70%and 3.553 kJ L^(−1)day^(−1),respectively,which indicate satisfactory performance of biomass as a direct combustion fuel.The CO_(2)fixation rate,which was calculated based on the carbon content in the biomass,was 0.309 g CO_(2)L^(−1)day^(−1).Therefore,large amounts of CO_(2)can be reduced using the large-scale microalgal cultivation system,which enables efficient biological CO_(2)conversion and maximizes microalgal biomass utilization.展开更多
Single-atom catalysts(SACs)have emerged as promising materials in energy conversion and storage systems due to their maximal atom utilization,unique electronic structure,and high efficiency.Among them,main-group metal...Single-atom catalysts(SACs)have emerged as promising materials in energy conversion and storage systems due to their maximal atom utilization,unique electronic structure,and high efficiency.Among them,main-group metal-based SACs(the s-block and p-block metals)are emerging extraordinary materials and have attracted particular interest in the past few years but are still confronted with several challenges.Initiating with a critical overview of the fundamentals and unique advantages associated with main-group metals,the review proceeds to highlight several types of main-group metal-based SACs.These include s-block metals such as Mg and Ca,and p-block metals such as In,Bi,Al,Ga,Sb,Se,and Sn.The applications of these SACs in diverse chemical energy conversion processes are thoroughly explored.Finally,to promote the future development of highly efficient main-group metal SACs,the critical challenges and prospects in this emerging field are proposed.This review presents a fresh impetus and solid platform for the rational design and synthesis of high-performance main-group metal SAC catalysts for chemical energy conversion fields.展开更多
CONSPECTUS:Hydrogen generation from electrocatalytic water splitting is widely regarded as an important energy conversion process based on its high compatibility with clean and renewable energy sources.It thus has the...CONSPECTUS:Hydrogen generation from electrocatalytic water splitting is widely regarded as an important energy conversion process based on its high compatibility with clean and renewable energy sources.It thus has the potential to help society achieve cleanness and sustainability.For the long-term production of highly purified hydrogen for industrial applications,it is preferred for the hydrogen evolution reaction(HER)to occur under mild working conditions or in alkaline media.However,such practical reaction efficiencies are hindered by additional water dissociation and multistep electron transfer.This stems from the sluggish kinetics of the HER in alkaline media,where the reaction rate is 2 to 3 orders of magnitude lower than in acidic media.Up to now,Pt has been extensively accepted as the symbolic catalyst for HER thanks to its appropriate hydrogen adsorption capability.Unfortunately,its activity is not acceptable due to its poor efficiency for water dissociation in alkaline solutions.In this regard,advanced catalysts that have both high catalytic activity for water dissociation and an appropriate hydrogen adsorption capacity are highly desired.Among the reported Pt-free catalysts for alkaline HER,Rh-based electrocatalysts exhibit obviously enhanced performances.It has been experimentally and theoretically confirmed that the Rh catalyst is located near the top of the Trasatti volcano plot for the HER,indicating its suitable adsorption energy of H*to facilitate the HER.In addition,the Rh catalyst possesses stronger competence for water dissociation than the Pt catalyst,which is a prerequisite for highly effective alkaline HER.In this context,a series of experiments with Rh-based electrocatalysts toward the alkaline HER have been actualized over the past decades.These proposed Rhbased catalysts have displayed impressive performances and promising prospects for hydrogen production.To realize the industrial application of hydrogen generation,Rh-based catalysts still require development,such as with the conceptual design of the catalysts and corresponding advanced synthesis methods.In short,further improvement of the catalytic performances of Rh-based catalysts depends on the development of various regulation strategies.In this Account,we highlight the recent progress and achievements of the regulation strategies for Rh-based catalysts and the corresponding enhancement principle for alkaline HER.We start with an introduction and comparison of the different mechanisms in acidic versus alkaline HER processes,emphasizing the principles of designing highly efficient catalysts toward alkaline HER.On the basis of previously reported studies,we conduct an in-depth discussion about the regulation strategies for Rh-based electrocatalysts and the performance optimization toward alkaline HER.This part is divided into three sections:structural engineering(e.g.,size,alloy,and morphology regulation),surface engineering(e.g.,element doping,facet controlling,and compound constructing),and interface engineering(e.g.,Rh/compound and Rh/carbon interfaces).The effective electronic modulation of Rhbased catalysts in these strategies is also outlined.At the end of this Account,some insights regarding the current challenges of Rhbased catalysts for alkaline HER and future research directions in this exciting field are provided.展开更多
MOFs are among the most popular precursors and templates for deriving various porous materials,where the derivatives can inherit a large surface area,abundant active sites for targeted functionalities and a high degre...MOFs are among the most popular precursors and templates for deriving various porous materials,where the derivatives can inherit a large surface area,abundant active sites for targeted functionalities and a high degree of porosity inherited from their parent MOFs.Those unique structural features make them promising candidates in multiple applications.More interestingly,the structure and properties of these MOF derivatives can be modulated by the choice of the parent MOFs and the design in the conversion process.In this overview,the transformation pathways from MOFs into their porous derivatives,the principles underlying these transformations,and the behavior of the MOF components in the transition process are discussed.Recently,there has been tremendous progress in preserving and enhancing the surface area,the amount of active sites and the level of porosity of the MOF-derived materials for targeted applications,from the perspectives of both customizing the parent MOFs and tailoring the transformation process.To develop the rationally designed MOF-derived materials and thus to elucidate the precursor-process-product correlations,some typical examples of the MOF derivatives applied in electrochemical energy storage and conversion,water treatment,gas sensing,and biomedicine are discussed to demonstrate the effectiveness of the key design strategies.展开更多
基金financial support offered by the National Key R&D Program of China(Grant No.2019YFA0705502,Grant No.2019YFA0705501)the National Natural Science Fund Project of China(Grant No.4210020395)+1 种基金the China Postdoctoral Science Foundation(Grant No.2021M700053)Technology Development Plan Project of Jilin Province(Grant No.20200201219JC).
文摘The autothermic pyrolysis in-situ conversion process (ATS) consumes latent heat of residual organic matter after kerogen pyrolysis by oxidation reaction, and it has the advantages of low development cost and exploitation of deep oil shale resources. However, the heating mechanism and the characteristic of different reaction zones are still unclear. In this study, an ATS numerical simulation model was proposed for the development of oil shale, which considers the pyrolysis of kerogen, high-temperature oxidation, and low-temperature oxidation. Based on the above model, the mechanism of the ATS was analyzed and the effects of preheating temperature, O_(2) content, and injection rate on recovery factor and energy efficiency were studied. The results showed that the ATS in the formation can be divided into five characteristic zones by evolution of the oil and O_(2) distribution, and the solid organic matter, including residue zone, autothermic zone, pyrolysis zone, preheating zone, and original zone. Energy efficiency was much higher for the ATS than for the high-temperature nitrogen injection in-situ conversion process (HNICP). There is a threshold value of the preheating temperature, the oil content, and the injection rate during the ATS, which is 400 °C, 0.18, and 1100 m3/day, respectively, in this study.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.52173023,21704082 and 21875182)Key Scientific and Technological Innovation Team Project of Shaanxi Province(No.2020TD-002)Natural Science Foundation of Shaanxi Province(No.2020JQ-015),and 111 project 2.0(No.BP2018008).The X-ray data of this research was undertaken on the SAXS/WAXS beamline at the Australian Synchrotron,part of ANSTO.
文摘The aligned molecular packing structure is vital to the anisotropic charge transport in conjugated polymer and small molecule thin films.However,how this molecular packing motif influences the photoelectric conversion process at the donor/acceptor heterojunction is still mysterious.Herein,we employed a PM6/Y6 bilayer model to investigate the long-range alignment of molecular packing induced photoelectric conversion process.Both PM6 and Y6 layers were properly controlled to exhibit the uniaxially oriented molecular packing compared to their as-cast counterparts,as revealed by the polarized absorption spectra and transmission electron microscopy.After analyzing the photovoltaic performance of bilayer devices,the smaller energy loss,lower energetic disorder,and longer charge carrier lifetime can be observed in the bilayer devices with aligned Y6 molecules,which contribute to a higher power conversion efficiency(PCE)than the as-cast devices.While the molecular packing structure of PM6 layer exhibited negligible influence on the device performance,probably resulting from the intrinsic semicrystalline nature of PM6 molecules.Our results indicate that the alignment of small molecular acceptor at the donor/acceptor interfaces should be a powerful strategy to facilitate the photoelectric conversion process,which will definitely pave the way to highly efficient bulk heterojunction photovoltaic device.
基金the financial support from the National Science Foundation of China(No.52374063 and No.52204065)the Natural Science Foundation of Shandong Province,China(No.ZR2023ME049 and No.ZR2021JQ18)the Fundamental Research Funds for the Central Universities,China(24CX06017A)。
文摘Simulation of thermal-reactive-compositional flow processes is fundamental to the thermal recovery of ultra-heavy hydrocarbon resources,and a typical oilfield practice is the in-situ conversion process(ICP)implemented in oil shale exploitation.However,accurately capturing the intricate flow dynamics of ICP requires a large number of fine-scale grid-blocks,which renders ICP simulations computationally expensive.Apart from that,plenty of oil shale reservoirs contain natural fractures or require hydraulic fracturing to enhance fluid mobility,creating further challenges in modeling pyrolysis reactions in both rock matrices and fractures.Targeted at the above issues,this work proposes a novel dual-model dualgrid upscaling(DDU)method specifically designed for solid-based thermal-reactive-compositional flow simulations in fractured porous media.Unlike existing upscaling techniques,the DDU method incorporates the upscaling of fracture grids using the embedded discrete fracture modeling(EDFM)approach and introduces a new concept of simplified models to approximate fine-scale results,which are used to correct reaction rates in coarse-scale grids.This method uniquely achieves efficient upscaling for both matrix and fracture grids,supports both open-source and commercial simulation platforms without modifying source codes,and is validated through 3D ICP models with natural fractures.The results indicate that the application of the DDU method can provide a close match with the fine-scale simulation results.Moreover,the DDU method has drastically improved the computational efficiency and speeded up the fine-scale simulation by 396-963 times.Therefore,the proposed DDU method has achieved marked computational savings while maintaining high simulation accuracy,which is significant for the development efficiency and production forecasting of oil shale reservoirs.
基金supported by PetroChina Co Ltd.(Grant number:2015D-4810-02,2018YCQ03,2021DJ52)National Natural Science Foundation of China(Grant number:42172170)
文摘The purpose of this study is to investigate the entire evolution process of shales with various total organic contents(TOC)in order to build models for quantitative evaluation of oil and gas yields and establish methods for assessing recoverable oil and gas resources from in-situ conversion of organic matters in shale.Thermal simulation experiments under in-situ conversion conditions were conducted on Chang 7_(3) shales from the Ordos Basin in a semi-open system with large capacity.The results showed that TOC and R_(o) were the key factors affecting the in-situ transformation potential of shale.The remaining oil and gas yields increased linearly with TOC but inconsistently with R_(o).R_(o) ranged 0.75%—1.25%and 1.05%—2.3%,respectively,corresponding to the main oil generation stage and gas generation stage of shale in-situ transformation.Thus a model to evaluate the remaining oil/gas yield with TOC and R_(o) was obtained.The TOC of shale suitable for in-situ conversion should be greater than 6%,whereas its R_(o) should be less than 1.0%.Shales with 0.75%(R_(o))could obtain the best economic benefit.The results provided a theoretical basis and evaluation methodology for predicting the hydrocarbon resources from in-situ conversion of shale and for the identification of the optimum“sweet spots”.The assessment of the Chang 7_(3) shale in the Ordos Basin indicated that the recoverable oil and gas resources from in-situ conversion of organic matters in shale are substantial,with oil and gas resources reaching approximately 450×10^(8) t and 30×10^(12)m^(3),respectively,from an area of 4.27×10^(4) km^(2).
基金Project supported by the National Basic Research Program of China(Grant No.2013CB632704)
文摘Tunable coherent emission is generated in a single-pass, cascaded wavelength conversion process from mode-locked laser-pumped monolithic periodically poled lithium niobate（PPLN）. Three ranges of wavelength, including visible output from 628 nm to 639 nm, near-infrared output from 797 nm to 816 nm, and mid-infrared output from 3167 nm to 3459 nm,were obtained from the monolithic PPLN, which consists of a 10-mm section for 532-nm-pumped optical parametric generation（OPG） and a 7-mm section for 1064-nm-pumped sum frequency generation（SFG）. A pump-to-signal conversion efficiency of 23.4% for OPG at 50°C and a quantum efficiency of 26.2% for SFG at 200°C were obtained.
基金financial support from the China Scholarship Council(CSC grant.201808330389)。
文摘MoS_(2) is a highly promising material for application in lithium-ion battery anodes due to its high theoretical capacity and low cost.However,problems with a fast capacity decay over cycling,especially at the first cycles,and poor rate performance have deterred its practical implementation.Herein,electrodes comprised solely of few-layers 2D MoS_(2) nanosheets have been manufactured by scalable liquid-phase exfoliation and spray deposition methods.The long-standing controversy questioning the reversibility of conversion processes of MoS_(2)-based electrodes was addressed.Raman studies revealed that,in 2D MoS_(2) electrodes,conversion processes are indeed reversible,where nanostructure played a key role.Cycling of the electrodes at high current rates revealed an intriguing phenomenon consisting of a continuously increasing capacity after ca.100-200 cycles.This phenomenon was comprehensively addressed by a variety of electrochemical and microscopy methods that revealed underlying physical activation mechanisms that involved a range of profound electrode structural changes.Activation mechanisms delivered a capacitive electrode of a superior rate performance and cycling stability,as compared to the corresponding pristine electrodes,and to MoS_(2) electrodes previously reported.Herein,we have devised a methodology to overcome the problem of cycling stability of 2D MoS_(2) electrodes.Moreover,activation of electrodes constitutes a methodology that could be applied to enhance the energy storage performance of electrodes based on other 2D nanomaterials,or combinations thereof,strategically combining chemistries to engineer electrodes of superior energy storage properties.
文摘In the suburbs of Kitakyushu,Japan,the inorganic aerosol mass concentration(IAM)was about 32.7μg/m^(3),with the aerosol pH of 3.3.To study the thermodynamics of aerosol when its individual components'concentration is reduced,sensitive tests were performed using the ISORROPIAⅡmodel,in which the seven control species—TNaCl,TNH_(4)^(+),TSO_(4)^(2-),TNO_(3)^(-),TMg^(2+),TK^(+),and TCa^(2+)—were taken into account.IAM and inorganic aerosol pH after reducing TNaCl,TNO_(3)^(-),TMg^(2+),TK^(+),and TCa^(2+)responded linearly(0%≤concentration reduction ratio(CRR)≤100%,with the exception of 100%in TNaCl);the nonlinear variations of these two parameters could be observed by controlling TNH_(4)^(+)and TSO_(4)^(2-).Unexpected aerosol behavior occurred at 100%reduction of TNaCl,which was caused by the sudden increase of NO_(3)^(-),NH_(4)^(+),and aerosol liquid water content(ALWC);the increase of IAM was also observed after controlling TSO_(4)^(2-)(60%≤CRR≤100%)and TCa^(2+)(0%≤CRR≤100%),which was mainly related to the variation of ALWC driven by the response of CaSO_(4).Multiple regression analysis showed that ALWC was statistically and strongly related to the variations of NO_(3)^(-),Cl-,SO_(4)^(2-),HSO_(4)^(-),HNO_(3),and NH_(3)(P<0.05),with regression coefficients of 1.68,5.23,1.83,2.81,0.34,and 0.57,respectively.The highest coefficient(5.23)was found for Cl^(-),revealing that sea salts significantly influenced particle responses.Overall,this study comprehensively investigated aerosol characteristics and inner responses for the reduction of components,which is of great significance for a better understanding of atmospheric chemistry in Kitakyushu,Japan.
基金supported by the Key Scientific and Technological Project‘‘Seismic-Sedimentology Software System Investigation and Application’’of Petro China Company Limited(2012B-3709)
文摘In contrast to marine deposits, continental deposits in China are characterized by diverse sedimentary types, rapid changes in sedimentary facies, complex lithology, and thin, small sand bodies. In seismic sedimentology studies on continental lacustrine basins, new thinking and more detailed and effective technical means are needed to generate lithological data cubes and conduct seismic geo- morphologic analyses. Based on a series of tests and studies, this paper presents the concepts of time-equivalent seismic attributes and seismic sedimentary bodies and a ＂four-step approach＂ for the seismic sedimentologic study of conti- nental basins： Step 1, build a time-equivalent stratigraphic framework based on vertical analysis and horizontal corre- lation of lithofacies, electrofacies, seismic facies, and pale- ontological combinations; Step 2, further build a sedimentary facies model based on the analysis of single- well facies with outcrop, coring, and lab test data; Step 3, convert the seismic data into a lithological data cube reflecting different lithologies by means of seismic tech- niques; and Step 4, perform a time-equivalent attribute analysis and convert the planar attribute into a sedimentary facies map under the guidance of the sedimentary facies model. The whole process, highlighting the verification and calibration of geological data, is an iteration and feedback procedure of geoseismic data. The key technologies include the following： （1） a seismic data-lithology conversion technique applicable to complex lithology, which can convert the seismic reflection from interface types to rock layers; and （2） time-equivalent seismic unit analysis and a time- equivalent seismic attribute extraction technique. Finally, this paper demonstrates the validity of the approach with an example from the Qikou Sag in the Bohai Bay Basin and subsequent drilling results.
基金supported by National Natural Science Foundation of China(52161145403 and 22072164)the Joint Fund of the Yulin University and the Dalian National Laboratory for Clean Energy(Grant.YLU-DNL Fund 2022002)。
文摘Despite the long tradition of fossil carbon(coal,char,and related carbon-based materials)for fueling mankind,the science of transforming them into chemicals is still demandingly progressing in the current energy scenario,especially when considering its responsibilities to the global climate change.Traditionally,there are four routes of preparing chemicals directly from fossil carbon,including hydrogasification,gasification,direct liquefaction,and oxidation,in the macroscope of gas-solid reaction(hydrogasification and gasification)and liquid-solid reaction(direct liquefaction and oxidation).When the study goes to microscale,the gas-solid reaction can be considered as the reaction between the severe condensed radicals and gas,while the liquid-solid reaction is the direct reaction between the radical and the activated-molecule.To have a full overview of the area,this review systematically summarizes the main factors in these processes and shows our own perspectives as follows,(ⅰ)stabilizing the free radicals generated from coal and then directly converting them has the highest efficiency in coal utilization;(ⅱ)the research on the self-catalytic process of coal structure will have a profound impact on the direct preparation of chemicals from fossil carbon.Further discussions are also proposed to guide the future study of the area into a more sustainable direction.
基金the National Natural Science Foundation of China(No.2 0 0 730 35
文摘The effect of thiourea(TU) on the nickel deposition process was analyzed by means of linear-sweep voltammetry. Raman spectroscopy and infrared reflectance spectroscopy were used to investigate the adsorption of TU and the formation of nickel-TU complexes on copper surface. The experimental results indicate that the nucleation and the preceding conversion step are involved in the deposition of nickel on copper electrodes. TU makes the onset nucleation potential negative due to the formation of nickel-TU complexes, which can accelerate the nickel deposition. Moreover, the S atom in the TU molecule adsorbed on copper surface facilitates the coordination of TU to Ni 2+ . Meanwhile, TU might be adsorbed at a flatter orientation if no Ni 2+ is on the surface, while at a perpendicular orientation when Ni 2+ is coadsorbed.
基金National Natural Science Foundation of China(62175090)Basic and Applied Basic Research Foundation of Guangdong Province(2024A1515011846)Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2019BT02X105)。
文摘Semiconductor metal oxides with narrow bandgap have emerged as a promising platform for photoelectrochemical reactions,yet their photoelectron-induced photocorrosion effect has been a limitation for their wider applications.Understanding the conversion processes concomitant with photoelectrochemical reaction at the electrode-electrolyte interface plays a crucial role in revealing the corrosion mechanisms and advancing the development of efficient photocathodes.However,accurately and in situ tracking these dynamic chemical events remains a great challenge due to the fact that reaction processes occur at nanoscale interfaces.Here,we track the electrochemical growth and conversion of copper nanostructures at interface by the evanescent field of the surface plasmon wave by using a gold-coated optical fiber as an electrochemical electrode and light sensing probe.The results exhibit correlation between redox processes of copper species and plasmonic resonances.Furthermore,in situ fiber-optic detection reveals the photocorrosion dynamics under photoelectrochemical reaction,including photoelectron-induced self-reduction of copper oxide and self-oxidation of cuprous oxide.These demonstrations facilitate not only the diagnosis for the health condition of photocathode nanomaterial,but also the understanding of the underlying reaction mechanism,and thus are potentially crucial for advancing the development of highly efficient photocathodes in future energy applications.
基金This work was supported by the Korea CCS R&D Center(Korea CCS 2020 Project)of the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT of Korea[Grant number 2014M1A8A1049278]the Korea Institute of Energy Technology Evaluation and Planning(KETEP)Grant funded by the Korean government(Ministry of Trade,Industry and Energy)[Grant number 20172010202050].
文摘Microalgae have piqued renewed interest as a sustainable biofuel feedstock owing to their high CO_(2)conversion efficiency.However,the major limitation of microalga-based biofuel production is low productivity.In this study,CO_(2)in flue gas emitted from the coal-fired power plants was fixed through mass microalgal cultivation using only sunlight as an energy source.To minimize the cost and energy required to supply the flue gas and efficiently utilize the microalgal biomass,a polycarbonate(PC)greenhouse and polymeric photobioreactors were installed near the power plant stack.Four different microalgal strains(Chlamydomonas reinhardtii,Chlorella sorokiniana,Neochloris oleoabundans,and Neochloris oleoabundans#13)were subjected to semi-continuous culturing for 1 month.The maximum biomass productivity was achieved by the N.oleoabun-dans#13 strain(0.703 g L^(−1)day^(−1)).Additionally,polymerase chain reaction analysis revealed that the individual microalgal culture was not cross-contaminated with other microalgal cultures in this cultivation system,owing to the structural proper-ties of photobioreactor comprising individual modules.The lipid content and calorific productivity of N.oleoabundans#13 biomass were 45.70%and 3.553 kJ L^(−1)day^(−1),respectively,which indicate satisfactory performance of biomass as a direct combustion fuel.The CO_(2)fixation rate,which was calculated based on the carbon content in the biomass,was 0.309 g CO_(2)L^(−1)day^(−1).Therefore,large amounts of CO_(2)can be reduced using the large-scale microalgal cultivation system,which enables efficient biological CO_(2)conversion and maximizes microalgal biomass utilization.
基金financially supported by the National Natural Science Foundation of China(52301013,52201009 and 52231008)the Hainan Provincial Natural Science Foundation of China(223RC401)+3 种基金the Education Department of Hainan Province(Hnky2023ZD-2,Hnky2024ZD-2)the Starting Research Funds of the Hainan University of China[KYQD(ZR)-21105,KYQD(ZR)-23090]the Collaborative Innovation Center of Marine Science and Technology,Hainan University(XTCX2022HYC18,XTCX2022HYC22)the Scientific and Technological Project of Yunnan Precious Metals Laboratory(YPML-2023050268).
文摘Single-atom catalysts(SACs)have emerged as promising materials in energy conversion and storage systems due to their maximal atom utilization,unique electronic structure,and high efficiency.Among them,main-group metal-based SACs(the s-block and p-block metals)are emerging extraordinary materials and have attracted particular interest in the past few years but are still confronted with several challenges.Initiating with a critical overview of the fundamentals and unique advantages associated with main-group metals,the review proceeds to highlight several types of main-group metal-based SACs.These include s-block metals such as Mg and Ca,and p-block metals such as In,Bi,Al,Ga,Sb,Se,and Sn.The applications of these SACs in diverse chemical energy conversion processes are thoroughly explored.Finally,to promote the future development of highly efficient main-group metal SACs,the critical challenges and prospects in this emerging field are proposed.This review presents a fresh impetus and solid platform for the rational design and synthesis of high-performance main-group metal SAC catalysts for chemical energy conversion fields.
基金supported by the Shanxi Province Science Foundation(20210302124446 and 202102070301018)the Basic Research Project from Institute of Coal Chemistry,CAS(SCJC-HN-2022-17).
文摘CONSPECTUS:Hydrogen generation from electrocatalytic water splitting is widely regarded as an important energy conversion process based on its high compatibility with clean and renewable energy sources.It thus has the potential to help society achieve cleanness and sustainability.For the long-term production of highly purified hydrogen for industrial applications,it is preferred for the hydrogen evolution reaction(HER)to occur under mild working conditions or in alkaline media.However,such practical reaction efficiencies are hindered by additional water dissociation and multistep electron transfer.This stems from the sluggish kinetics of the HER in alkaline media,where the reaction rate is 2 to 3 orders of magnitude lower than in acidic media.Up to now,Pt has been extensively accepted as the symbolic catalyst for HER thanks to its appropriate hydrogen adsorption capability.Unfortunately,its activity is not acceptable due to its poor efficiency for water dissociation in alkaline solutions.In this regard,advanced catalysts that have both high catalytic activity for water dissociation and an appropriate hydrogen adsorption capacity are highly desired.Among the reported Pt-free catalysts for alkaline HER,Rh-based electrocatalysts exhibit obviously enhanced performances.It has been experimentally and theoretically confirmed that the Rh catalyst is located near the top of the Trasatti volcano plot for the HER,indicating its suitable adsorption energy of H*to facilitate the HER.In addition,the Rh catalyst possesses stronger competence for water dissociation than the Pt catalyst,which is a prerequisite for highly effective alkaline HER.In this context,a series of experiments with Rh-based electrocatalysts toward the alkaline HER have been actualized over the past decades.These proposed Rhbased catalysts have displayed impressive performances and promising prospects for hydrogen production.To realize the industrial application of hydrogen generation,Rh-based catalysts still require development,such as with the conceptual design of the catalysts and corresponding advanced synthesis methods.In short,further improvement of the catalytic performances of Rh-based catalysts depends on the development of various regulation strategies.In this Account,we highlight the recent progress and achievements of the regulation strategies for Rh-based catalysts and the corresponding enhancement principle for alkaline HER.We start with an introduction and comparison of the different mechanisms in acidic versus alkaline HER processes,emphasizing the principles of designing highly efficient catalysts toward alkaline HER.On the basis of previously reported studies,we conduct an in-depth discussion about the regulation strategies for Rh-based electrocatalysts and the performance optimization toward alkaline HER.This part is divided into three sections:structural engineering(e.g.,size,alloy,and morphology regulation),surface engineering(e.g.,element doping,facet controlling,and compound constructing),and interface engineering(e.g.,Rh/compound and Rh/carbon interfaces).The effective electronic modulation of Rhbased catalysts in these strategies is also outlined.At the end of this Account,some insights regarding the current challenges of Rhbased catalysts for alkaline HER and future research directions in this exciting field are provided.
基金the National Research Foundation(NRF)Singapore for funding under NRF-CRP17-2017-01(R-284-000-165-281)for the research conducted at the National University of Singapore.
文摘MOFs are among the most popular precursors and templates for deriving various porous materials,where the derivatives can inherit a large surface area,abundant active sites for targeted functionalities and a high degree of porosity inherited from their parent MOFs.Those unique structural features make them promising candidates in multiple applications.More interestingly,the structure and properties of these MOF derivatives can be modulated by the choice of the parent MOFs and the design in the conversion process.In this overview,the transformation pathways from MOFs into their porous derivatives,the principles underlying these transformations,and the behavior of the MOF components in the transition process are discussed.Recently,there has been tremendous progress in preserving and enhancing the surface area,the amount of active sites and the level of porosity of the MOF-derived materials for targeted applications,from the perspectives of both customizing the parent MOFs and tailoring the transformation process.To develop the rationally designed MOF-derived materials and thus to elucidate the precursor-process-product correlations,some typical examples of the MOF derivatives applied in electrochemical energy storage and conversion,water treatment,gas sensing,and biomedicine are discussed to demonstrate the effectiveness of the key design strategies.
