LnVO_(4)(Ln=La,Ce,Pr,Nd,etc.)is an emerging photocatalyst for solving the energy and environmental crisis,due to its suitable band gap,special valence electronic structure,high thermal,and chemical sta-bility,as well ...LnVO_(4)(Ln=La,Ce,Pr,Nd,etc.)is an emerging photocatalyst for solving the energy and environmental crisis,due to its suitable band gap,special valence electronic structure,high thermal,and chemical sta-bility,as well as excellent photocatalytic performance.Although exhibiting great promise,the low solar power employment efficiency of LnVO_(4) materials has limited its further development and application.However,recent breakthroughs have been made in both heightening its photocatalysis efficiency and elu-cidating the essential photocatalytic mechanisms.Therefore,it is important to review and summarize recent research progress on LnVO_(4) nanomaterials and their applications.In this review,we systemat-ically report on and examine recent computational and experimental advances in the modification of LnVO_(4)-based photocatalysts through morphology adjustment,elemental doping,phase structure modula-tion,crystal facet modulation,defect modulation,heterostructure,and beyond.Thereafter,we outline cur-rent promising photocatalytic applications and discuss challenges/expected upcoming research aims for LnVO_(4)-based photocatalysts.Our goal is to furnish guidance for the reasonable design and preparation of highly efficient LnVO_(4)(Ln=La,Ce,Pr,Nd,etc.)-based photocatalytic materials for sundry applications.展开更多
Single-atom catalysts(SACs)have been a research hotspot due to their high catalytic activity,selectivity,and atomic utilization rates.However,the theoretical research of SACs is relatively fragmented,which restricts f...Single-atom catalysts(SACs)have been a research hotspot due to their high catalytic activity,selectivity,and atomic utilization rates.However,the theoretical research of SACs is relatively fragmented,which restricts further understanding of SAC stability and activity.To address this issue,we report our analysis of the geometric structures,electronic characteristics,stabilities,catalytic activities,and descriptors of 132 graphene-based singleatom catalysts(M/GS)obtained from density functional theory calculations.Based on the calculated formation and binding energies,a stability map of M/GS was established to guide catalyst synthesis.The effects of metal atoms and support on the charge of metal atoms are discussed.The catalytic activities of M/GS in both nitrogen and oxygen reduction reactions are predicted based on the calculated magnetic moment and the adsorption energy.Combined with the electronegativity and d-band center,a two-dimensional descriptor is proposed to predict the O adsorption energy on M/GS.More importantly,this theoretical study provides predictive guidance for the preparation and rational design of highly stable and active single-atom catalysts using nitrogen doping on graphene.展开更多
From a time value of revenue point of view,it is preferred that the time between reservoir stimulation and oil production response is small.Heavy oil combustion processes have a lag time between air injection and liqu...From a time value of revenue point of view,it is preferred that the time between reservoir stimulation and oil production response is small.Heavy oil combustion processes have a lag time between air injection and liquid production,but the common practice in production data analysis uses simultaneous injection and production data when seeking a relationship between them.In this research,the time scales of production for the Kerrobert toe-to-heel air injection(THAI)heavy oil project in Saskatchewan,Canada,is analyzed by using cross correlation analysis,i.e.time delay analysis between air injection and oil production.The results reveal two time scales with respect to production response with two distinctive recovery mechanisms:(1)a short time scale response(nearly instantaneous)where oil production peaks right after air injection(directly after opening production well)reflecting cold heavy oil production mechanisms,and(2)a longer time scale(of order of 100-300 days)response where peak production occurs associated with the collective phenomena of air injection,heat generating reactions,heat transfer,and finally,heated mobilized heavy oil drainage to the production well.This understanding of the two time scales and associated production mechanisms provides a basis for improving the performance of THAI.展开更多
Aqueous supercapacitors(SCs)have been regarded as a promising candidate for commercial energy storage device due to their superior safety,low cost,and environmental benignity.Unfortunately,an age-old challenge of achi...Aqueous supercapacitors(SCs)have been regarded as a promising candidate for commercial energy storage device due to their superior safety,low cost,and environmental benignity.Unfortunately,an age-old challenge of achieving both long electrode lifespan and qualified energy-storage property blocks their practical application.Herein,we develop an electrode-electrolyte integrated optimization strategy to fulfill the real-life device requirements.Electrode optimization simultaneously regulates the nanomorphology and surface chemistry of the tungsten oxide anode,resulting in superior electrochemical performance given by an ideal“bird-nest”structure with optimal oxygen vacancy status;the anodes interact with and are protected from dissolution and structural collapse by the rationally designed hybrid electrolyte with optimized pH and facilitated cation desorption behavior.Collaboratively,a record-breaking durability of no capacitive decay after 250000 cycles is achieved.On the basis of this integrated optimization,the first aqueous pouch SCs with real-life practicability were manufactured by a soft-package encapsulation technique,which can steadily power commercial 3 C products such as tablets and smartphones and maintain safely working against extreme conditions.This work demonstrates the possibility of using aqueous energy storage devices with enhanced safety and lower cost to replace the commercial organic counterparts for wide range of daily applications.展开更多
Numerous researchers have examined the co-current flow of oil-water and aqueous solutions containing polymers and surfactants in thin gaps for oil recovery.While some have focused on charges and forces at the interfac...Numerous researchers have examined the co-current flow of oil-water and aqueous solutions containing polymers and surfactants in thin gaps for oil recovery.While some have focused on charges and forces at the interfaces of oil-surfactant solutions during flow.The study of flow structures,interface behavior,and relative permeabilities of oil and aqueous phases of surfactant flow through thin gaps has been less explored.For the first time,this research aims to comprehensively investigate the flow of oil-water and oil-surfactant solutions through a thin gap(Hele-Shaw cell)with a particular focus on the impact of sodium dodecyl sulfate(SDS).The experiments reveal that SDS forms an emulsion near the oil-water interface,capturing oil droplets and enabling their flow along with the SDS solution.Microscopic studies confirm this,showing that when SDS contacts oil,it creates channels through the oil phase,leading to the accumulation and division of oil into small round-shaped droplets,resulting in an oil-in-water emulsion.The addition of SDS to the injecting water significantly enhances relative permeabilities,leading to a remarkable 90%increase in oil recovery from the cell.The research suggests that the optimal SDS concentration range for maximum oil recovery is between 1.5 and 2 wt%,as it achieves the minimum interfacial tension between oil and water.展开更多
Steam Assisted Gravity Drainage(SAGD)is widely used in the Athabasca oil sands deposit to recover bitumen.Since the viscosity of bitumen is high at original reservoir conditions,heat is required to lower its viscosity...Steam Assisted Gravity Drainage(SAGD)is widely used in the Athabasca oil sands deposit to recover bitumen.Since the viscosity of bitumen is high at original reservoir conditions,heat is required to lower its viscosity to the point it becomes mobile enough to be recovered under gravity drainage.To heat the reservoir,steam is injected into the formation and thus SAGD is energy intense.Given that the fuel used to generate steam is the largest operating cost,the steam-to-oil ratio is one of the key parameter for evaluating the economics of any SAGD project.Here,the use of dynamic distributed steam injection within a pad of SAGD wellpairs is explored.The results demonstrate that feedback control leads to improvements of the SOR over that of constant pressure.The results show that the controller is able to detect the“sweet spots”(oil zones with better geological properties)in the reservoir and dynamically deliver more steam to that region.Meanwhile,it reduces the steam injection towards relatively worse quality zones to lower the local SOR.展开更多
基金National Natural Science Foundation of China(Nos.22076068,8111310014)(China)Global Research Initiative for Sustainable Low-Carbon Unconventional Resources(Canada)University of Calgary’s Canada First Research Excellence Fund(CFREF)program(Canada).
文摘LnVO_(4)(Ln=La,Ce,Pr,Nd,etc.)is an emerging photocatalyst for solving the energy and environmental crisis,due to its suitable band gap,special valence electronic structure,high thermal,and chemical sta-bility,as well as excellent photocatalytic performance.Although exhibiting great promise,the low solar power employment efficiency of LnVO_(4) materials has limited its further development and application.However,recent breakthroughs have been made in both heightening its photocatalysis efficiency and elu-cidating the essential photocatalytic mechanisms.Therefore,it is important to review and summarize recent research progress on LnVO_(4) nanomaterials and their applications.In this review,we systemat-ically report on and examine recent computational and experimental advances in the modification of LnVO_(4)-based photocatalysts through morphology adjustment,elemental doping,phase structure modula-tion,crystal facet modulation,defect modulation,heterostructure,and beyond.Thereafter,we outline cur-rent promising photocatalytic applications and discuss challenges/expected upcoming research aims for LnVO_(4)-based photocatalysts.Our goal is to furnish guidance for the reasonable design and preparation of highly efficient LnVO_(4)(Ln=La,Ce,Pr,Nd,etc.)-based photocatalytic materials for sundry applications.
基金the National Natural Science Foundation of China(No.91545122)Beijing Natural Science Foundation(2182066)+1 种基金Natural Science Foundation of Hebei Province of China(B2018502067)the Fundamental Research Funds for the Central Universities(2017XS121).
文摘Single-atom catalysts(SACs)have been a research hotspot due to their high catalytic activity,selectivity,and atomic utilization rates.However,the theoretical research of SACs is relatively fragmented,which restricts further understanding of SAC stability and activity.To address this issue,we report our analysis of the geometric structures,electronic characteristics,stabilities,catalytic activities,and descriptors of 132 graphene-based singleatom catalysts(M/GS)obtained from density functional theory calculations.Based on the calculated formation and binding energies,a stability map of M/GS was established to guide catalyst synthesis.The effects of metal atoms and support on the charge of metal atoms are discussed.The catalytic activities of M/GS in both nitrogen and oxygen reduction reactions are predicted based on the calculated magnetic moment and the adsorption energy.Combined with the electronegativity and d-band center,a two-dimensional descriptor is proposed to predict the O adsorption energy on M/GS.More importantly,this theoretical study provides predictive guidance for the preparation and rational design of highly stable and active single-atom catalysts using nitrogen doping on graphene.
基金support from the Department of Chemical and Petroleum Engineering at the University of Calgary,the University of Calgary’s Canada First Research Excellence Fund program(the Global Research Initiative for Sustainable Low-Carbon Unconventional Resources)
文摘From a time value of revenue point of view,it is preferred that the time between reservoir stimulation and oil production response is small.Heavy oil combustion processes have a lag time between air injection and liquid production,but the common practice in production data analysis uses simultaneous injection and production data when seeking a relationship between them.In this research,the time scales of production for the Kerrobert toe-to-heel air injection(THAI)heavy oil project in Saskatchewan,Canada,is analyzed by using cross correlation analysis,i.e.time delay analysis between air injection and oil production.The results reveal two time scales with respect to production response with two distinctive recovery mechanisms:(1)a short time scale response(nearly instantaneous)where oil production peaks right after air injection(directly after opening production well)reflecting cold heavy oil production mechanisms,and(2)a longer time scale(of order of 100-300 days)response where peak production occurs associated with the collective phenomena of air injection,heat generating reactions,heat transfer,and finally,heated mobilized heavy oil drainage to the production well.This understanding of the two time scales and associated production mechanisms provides a basis for improving the performance of THAI.
基金supported by the National Natural Science Foundation of China(Nos.52071171,52202248 and 22209064)Liaoning Revitalization Talents Program—Pan Deng Scholars(XLYC1802005)+9 种基金Liaoning Bai Qian Wan Talents Program(LNBQW2018B0048)Key Project of Scientific Research of the Education Department of Liaoning Province(LZD201902)Shenyang Science and Technology Project(21-108-9-04)Australian Research Council(ARC)through Future Fel owship(FT210100298,FT210100806)Discovery Project(DP220100603)Linkage Project(LP210100467,LP210200504,and LP210200345)Industrial Transformation Training Centre(IC180100005)schemes,CSIRO Energy Centre and Kick-Start ProjectStudy Melbourne Research Partnerships program has been made possible by funding from the Victorian Government through Study MelbourneShiyanjia Lab(www.shiyanjia.com)for the support of the XPS testsupport from the University of Calgary’s Canada First Research Excel ence Fund program,the Global Research Initiative for Sustainable Low-Carbon Unconventional Energy
文摘Aqueous supercapacitors(SCs)have been regarded as a promising candidate for commercial energy storage device due to their superior safety,low cost,and environmental benignity.Unfortunately,an age-old challenge of achieving both long electrode lifespan and qualified energy-storage property blocks their practical application.Herein,we develop an electrode-electrolyte integrated optimization strategy to fulfill the real-life device requirements.Electrode optimization simultaneously regulates the nanomorphology and surface chemistry of the tungsten oxide anode,resulting in superior electrochemical performance given by an ideal“bird-nest”structure with optimal oxygen vacancy status;the anodes interact with and are protected from dissolution and structural collapse by the rationally designed hybrid electrolyte with optimized pH and facilitated cation desorption behavior.Collaboratively,a record-breaking durability of no capacitive decay after 250000 cycles is achieved.On the basis of this integrated optimization,the first aqueous pouch SCs with real-life practicability were manufactured by a soft-package encapsulation technique,which can steadily power commercial 3 C products such as tablets and smartphones and maintain safely working against extreme conditions.This work demonstrates the possibility of using aqueous energy storage devices with enhanced safety and lower cost to replace the commercial organic counterparts for wide range of daily applications.
文摘Numerous researchers have examined the co-current flow of oil-water and aqueous solutions containing polymers and surfactants in thin gaps for oil recovery.While some have focused on charges and forces at the interfaces of oil-surfactant solutions during flow.The study of flow structures,interface behavior,and relative permeabilities of oil and aqueous phases of surfactant flow through thin gaps has been less explored.For the first time,this research aims to comprehensively investigate the flow of oil-water and oil-surfactant solutions through a thin gap(Hele-Shaw cell)with a particular focus on the impact of sodium dodecyl sulfate(SDS).The experiments reveal that SDS forms an emulsion near the oil-water interface,capturing oil droplets and enabling their flow along with the SDS solution.Microscopic studies confirm this,showing that when SDS contacts oil,it creates channels through the oil phase,leading to the accumulation and division of oil into small round-shaped droplets,resulting in an oil-in-water emulsion.The addition of SDS to the injecting water significantly enhances relative permeabilities,leading to a remarkable 90%increase in oil recovery from the cell.The research suggests that the optimal SDS concentration range for maximum oil recovery is between 1.5 and 2 wt%,as it achieves the minimum interfacial tension between oil and water.
文摘Steam Assisted Gravity Drainage(SAGD)is widely used in the Athabasca oil sands deposit to recover bitumen.Since the viscosity of bitumen is high at original reservoir conditions,heat is required to lower its viscosity to the point it becomes mobile enough to be recovered under gravity drainage.To heat the reservoir,steam is injected into the formation and thus SAGD is energy intense.Given that the fuel used to generate steam is the largest operating cost,the steam-to-oil ratio is one of the key parameter for evaluating the economics of any SAGD project.Here,the use of dynamic distributed steam injection within a pad of SAGD wellpairs is explored.The results demonstrate that feedback control leads to improvements of the SOR over that of constant pressure.The results show that the controller is able to detect the“sweet spots”(oil zones with better geological properties)in the reservoir and dynamically deliver more steam to that region.Meanwhile,it reduces the steam injection towards relatively worse quality zones to lower the local SOR.
