Background:Excessive heat exposure can lead to hyperthermia in humans,which impairs physical performance and disrupts cognitive function.While heat is a known physiological stressor,it is unclear how severe heat stres...Background:Excessive heat exposure can lead to hyperthermia in humans,which impairs physical performance and disrupts cognitive function.While heat is a known physiological stressor,it is unclear how severe heat stress affects brain physiology and function.Methods:Eleven healthy participants were subjected to heat stress from prolonged exercise or warm water immersion until their rectal temperatures(T_(re))attained 39.5℃,inducing exertional or passive hyperthermia,respectively.In a separate trial,blended ice was ingested before and during exercise as a cooling strategy.Data were compared to a control condition with seated rest(normothermic).Brain temperature(T_(br)),cerebral perfusion,and task-based brain activity were assessed using magnetic resonance imaging techniques.Results:T_(br)in motor cortex was found to be tightly regulated at rest(37.3℃±0.4℃(mean±SD))despite fluctuations in T_(re).With the development of hyperthermia,T_(br)increases and dovetails with the rising T_(re).Bilateral motor cortical activity was suppressed during high-intensity plantarflexion tasks,implying a reduced central motor drive in hyperthermic participants(T_(re)=38.5℃±0.1℃).Global gray matter perfusion and regional perfusion in sensorimotor cortex were reduced with passive hyperthermia.Executive function was poorer under a passive hyperthermic state,and this could relate to compromised visual processing as indicated by the reduced activation of left lateral-occipital cortex.Conversely,ingestion of blended ice before and during exercise alleviated the rise in both T_(re)and T_(bc)and mitigated heat-related neural perturbations.Conclusion:Severe heat exposure elevates T_(br),disrupts motor cortical activity and executive function,and this can lead to impairment of physical and cognitive performance.展开更多
Developing a flexible,light-weight and effective electromagnetic(EM)absorber remains challenging despite being on increasing demand as more wearable devices and portable electronics are commercialized.Herein,we report...Developing a flexible,light-weight and effective electromagnetic(EM)absorber remains challenging despite being on increasing demand as more wearable devices and portable electronics are commercialized.Herein,we report a flexible and lightweight hybrid paper by a facile vacuumfiltration-induced self-assembly process,in which cotton-derived carbon fibers serve as flexible skeletons,compactly surrounded by other microwave-attenuating components(reduced graphene oxide and Fe3O4@C nanowires).Owing to its unique architecture and synergy of the three components,the asprepared hybrid paper exhibits flexible and lightweight features as well as superb microwave absorption performance.Maximum absorption intensity with reflection loss as low as-63 dB can be achieved,and its broadest frequency absorption bandwidth of 5.8 GHz almost covers the entire Ku band.Such a hybrid paper is promising to cope with ever-increasing EM interference.The work also paves the way to develop low-cost and flexible EM wave absorber from biomass through a facile method.展开更多
Lithium-sulfur batteries(LSBs)are considered as the next generation of advanced rechargeable batteries because of their high energy density.In this study,sulfur and CoxS electrocatalyst are deposited on carbon nanotub...Lithium-sulfur batteries(LSBs)are considered as the next generation of advanced rechargeable batteries because of their high energy density.In this study,sulfur and CoxS electrocatalyst are deposited on carbon nanotube buckypaper(S/CoxS/BP)by a facile electrodeposition method and are used as a binder-free high-performance cathode for LSBs.Elemental sulfur is deposited on buckypaper by electrooxidation of a polysulfide solution(-S6^2-).This approach substantially increased the current and time efficiency of sulfur electrochemical deposition on conductive material for LSBs.S/CoxS/BP cathode could deliver an initial discharge capacity as high as 1650 mAh g^-1 at 0.1 C,which is close to the theoretical capacity of sulfur.At current rate of 0.5 C,the S/CoxS/BP has a capacity of 1420 mAh g^-1 at the first cycle and 715 mAh g^-1 after 500 cycles with a fading rate of 0.099%per cycle.The high capacity of S/CoxS/BP is attributed to both the homogeneous dispersion of nanosized sulfur within BP and the presence of CoxS catalyst.The sodium dodecyl sulfate(SDS)pretreatment of BP renders it polarity to bind polysulfides and thus facilitates the good dispersibility of nanosized sulfur within BP.CoxS catalyst accelerates the kinetics of polysulfide conversion and reduces the presence of polysulfide in the cathode,which suppresses the polysulfide diffusion to anode,i.e.,the shuttle effect.The mitigation of the active material loss improves not only the capacity but also the cyclability of S/CoxS/BP.展开更多
Carbonate electrolytes are one of the most desirable electrolytes for high-energy lithium-sulfur batteries(LSBs)because of their successful implementation in commercial Li-ion batteries.The low-polysulfide-solubility ...Carbonate electrolytes are one of the most desirable electrolytes for high-energy lithium-sulfur batteries(LSBs)because of their successful implementation in commercial Li-ion batteries.The low-polysulfide-solubility feature of some carbonate solvents also makes them very promising for overcoming the shuttle effects of LSBs.However,regular sulfur electrodes experience undesired electrochemical mechanisms in carbonate electrolytes due to side reactions.In this study,we report a catalytic redox mechanism of sulfur in propylene carbonate(PC)electrolyte based on a compari-son study.The catalytic mechanism is characterized by the interactions between polysulfides and dual N/O functional groups on the host carbon,which largely prevents side reactions between polysulfides and the carbonate electrolyte.Such a mechanism coupled with the low-polysulfide-solubility feature leads to stable cycling of LSBs in PC electrolyte.Favorable dual N/O functional groups are identified via a density functional theory study.This work provides an alternative route for enabling LSBs in carbonate electrolytes.展开更多
Electrochemical water splitting consists of two elementary reactions i.e.,hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).Developing robust HER and OER technologies necessitates a molecular picture ...Electrochemical water splitting consists of two elementary reactions i.e.,hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).Developing robust HER and OER technologies necessitates a molecular picture of reaction mechanism,yet the reactants for water splitting reactions are unfortunately not fully understood.Here we utilize magnetic field to understand proton transport in HER,and hydroxide ion transport in OER,to discuss the possible implications on understanding the reactants for HER and OER.Magnetic field is a known tool for changing the movement of charged species like ions,e.g.the magnetic‐field‐improved Cu^(2+)transportation near the electrode in Cu electrodeposition.However,applying a magnetic field does not affect the HER or OER rate across various pH,which challenges the traditional opinion that charged species(i.e.proton and hydroxide ion)act as the reactant.This anomalous response of HER and OER to magnetic field,and the fact that the transport of proton and hydroxide ion follow Grotthuss mechanism,collectively indicate water may act as the universal reactant for HER and OER across various pH.With the aid of magnetic field,this work serves as an understanding of water might be the reactant in HER and OER,and possibly in other electrocatalysis reactions involving protonation and deprotonation step.A model that simply focuses on the charged species but overlooking the complexity of the whole electrolyte phase where water is the dominant species,may not reasonably reflect the electrochemistry of HER and OER in aqueous electrolyte.展开更多
Tuning and optimization of electronic structures and related reaction energetics are critical toward the rational design of efficient electrocatalysts.Herein,experimental and theoretical calculation demonstrate the or...Tuning and optimization of electronic structures and related reaction energetics are critical toward the rational design of efficient electrocatalysts.Herein,experimental and theoretical calculation demonstrate the originally inert N site within polyaniline(PANI)can be activated for hydrogen evolution by proper d-πinterfacial electronic coupling with metal oxide.As a result,the assynthesized WO3 assemblies@PANI via a facile redox-induced assembly and in situ polymerization,exhibits the electrocatalytic production of hydrogen better than other control samples including W18O49@PANI and most of the reported nobel-metal-free electrocatalysts,with low overpotential of 74 mV at 10 mA·cm−2 and small Tafel slope of 46 mV·dec−1 in 0.5M H2SO4(comparable to commercial Pt/C).The general efficacy of this methodology is also validated by extension to other metal oxides such as MoO3 with similar improvements.展开更多
Sodium-ion capacitors(SICs)have received increasing interest for grid stationary energy storage application due to their affordability,high power,and energy densities.The major challenge for SICs is to overcome the ki...Sodium-ion capacitors(SICs)have received increasing interest for grid stationary energy storage application due to their affordability,high power,and energy densities.The major challenge for SICs is to overcome the kinetics imbalance between faradaic anode and nonfaradaic cathode.To boost the Na+reaction kinetics,the present work demonstrated a high-rate MnS-based anode by embedding the MnS nanocrystals into the N,S-co-doped carbon matrix(MnS@NSC).Benefiting from the fast pseudocapacitive Na+storage behavior,the resulting composite exhibits extraordinary rate capability(205.6 mAh g−1 at 10 A g−1)and outstanding cycling stability without notable degradation after 2000 cycles.A prototype SIC was demonstrated using MnS@NSC anode and N-doped porous carbon(NC)cathode;the obtained hybrid SIC device can display a high energy density of 139.8 Wh kg−1 and high power density of 11,500 W kg−1,as well as excellent cyclability with 84.5%capacitance retention after 3000 cycles.The superior electrochemical performance is contributed to downsizing of MnS and encapsulation of conductive N,S-co-doped carbon matrix,which not only promote the Na+and electrons transport,but also buffer the volume variations and maintain the structure integrity during Na+insertion/extraction,enabling its comparable fast reaction kinetics and cyclability with NC cathode.展开更多
This study aims to investigate the significance and biodegradation pathways of PHB-based bioplastic in anaerobic digesters treating food waste,where the reactor performance of changed methane generation,bioplastic bio...This study aims to investigate the significance and biodegradation pathways of PHB-based bioplastic in anaerobic digesters treating food waste,where the reactor performance of changed methane generation,bioplastic biodegradation efficiency,and bioinformatic analysis of functional microbes were emphasized.The results showed that PHB-based plastic film could be partially biodegraded in the food waste digester,and a bioaugmentation use of Alcaligenes Faecalis(AF)and Bacillus Megaterium(BM)was beneficial to largely accelerate the degradation process through a beneficial shift of both the functional bacterial and archaeal species.Microbial community analysis indicated that the major bacterial species belonged to genera Candidatus_Cloacimonas,Rikenellaceae,and Defluviitoga,while the dominant methanogenic archaeal species belonged to genera Methanomassiliicoccus,Methanosarcina,and Methanosaeta.Bioplastic biodegradation analysis suggested that the optimal fractions of AF and BM for PHB-based plastic degradation were 50% AF and 75% BM,respectively,which deserves further optimization and scale-up validation.The finding of this study would contribute to the combined management of PHB-based bioplastic with food waste for clean energy recovery and a greener environment.展开更多
LaFe_(11.8)Si_(1.2)/10 wt%Ce_(60)Co_(40) composites were prepared by spark plasma sintering and subsequent diffusion annealing.A novel core-shell structure is observed with the LaFe11.8Si1.2 particles as the core and ...LaFe_(11.8)Si_(1.2)/10 wt%Ce_(60)Co_(40) composites were prepared by spark plasma sintering and subsequent diffusion annealing.A novel core-shell structure is observed with the LaFe11.8Si1.2 particles as the core and the(La,Ce)_(2)(Fe,Co,Si)_(17)(2:17)phase as the shell.As diffusion annealing time(t_(a))increases,this core-shell structure is replaced by the formation of the(La,Ce)_(1)(Fe,Co,Si)_(13) phase.Annealing at 1323 K for 12 h results in samples with(-ΔSM)^(max) of 9.30 J/(kg·K)(Δμ0H=2 T),good mechanical properties((σbc)^(max)=402 MPa,ε=4.21%)and thermal conductivity of 8.7 W/(m·K).Thus,bulk composites with excellent comprehensive properties for magnetic refrigeration are obtained in this work.展开更多
Amorphous Fe78-xRExSi4 Nb5 B12Cu1(RE=Gd,Dy) ribbons with different RE contents were prepared by melt spinning to investigate the effect of heavy rare earth(Gd,Dy) substitution on the hyperfine structure,magnetic prope...Amorphous Fe78-xRExSi4 Nb5 B12Cu1(RE=Gd,Dy) ribbons with different RE contents were prepared by melt spinning to investigate the effect of heavy rare earth(Gd,Dy) substitution on the hyperfine structure,magnetic properties and magnetocaloric effect.The Curie temperature of RE substituted alloys,hyperfine field and magnetic moments of Fe atoms initially increase up to 1 at% RE content and then decrease monotonously for increasing RE content up to 10 at%.The dependence of magnetic entropy change(-△SM) and refrigeration capacity(RC) of the alloys on RE contents displays the same tendency.The RCAREA values of the alloys substituted with 1 at% Gd and Dy are similar to those of recently reported Fe-based metallic glasses with enhanced RC values compared with those of Gd5 Ge1.9Si2 Fe0.1.Enhanced-△SM and RC values,negligible coercive force and hysteresis commonly make these Fe78-xREx-Si4 Nb5 B12Cu1 amorphous alloys as low-cost candidates for high-temperature magnetic refrigeration.展开更多
Electrochemically producing formate by oxidizing methanol is a promising way to add value to methanol.Noble metal-based electrocatalysts,which have been extensively studied for the methanol oxidation reaction,can cata...Electrochemically producing formate by oxidizing methanol is a promising way to add value to methanol.Noble metal-based electrocatalysts,which have been extensively studied for the methanol oxidation reaction,can catalyze the complete oxidation of methanol to carbon dioxide,but not the mild oxidation to formate.As a result,exploring efficient and earth-abundant electrocatalysts for formate production from methanol is of interest.Herein,we present the electro-oxidation of methanol to formate,catalyzed by iron-substituted lanthanum cobaltite(LaCo_(1-x)Fe_(x)O_(3)).The Fe/Co ratio in the oxides greatly influences the activity and selectivity.This effect is attributed to the higher affinity of Fe and Co to the two reactants:CH3OH and OH,respectively.Because a balance between these affinities is favored,LaCo_(0.5)Fe_(0.5)O_(3) shows the highest formate production rate,at 24.5 mmol h^(-1) g_(oxide)^(-1),and a relatively high Faradaic efficiency of 44.4%in a series of(LaCo_(1-x)Fe_(x)O_(3))samples(x=0.00,0.25,0.50,0.75,1.00)at 1.6 V versus a reversible hydrogen electrode.展开更多
The evaluation of the intrinsic activity of catalysts is the most basic in searching energy-and cost-efficient catalyst materials for various applications.The accurate determination of the intrinsic activity is essent...The evaluation of the intrinsic activity of catalysts is the most basic in searching energy-and cost-efficient catalyst materials for various applications.The accurate determination of the intrinsic activity is essential for identifying efficient catalysts.While a huge number of studies of electrocatalysis for various applications have been reported,the effects of electrode loading on the apparent intrinsic activity obtained experimentally have been rarely discussed.With a high mass loading on the electrode,not all the catalyst surfaces can be electrochemically active because not all the surfaces can be wetted by the electrolyte.The loading also affects the transport of electrons over the electrode as well as the transport of ions in the electrolyte,and thus affects the kinetics.These lead to the derivations of the apparent intrinsic activity from the real intrinsic activity.Herein,for better understanding the derivations,we evaluate and discuss the effects of electrode mass loading using oxygen evolution reaction as an example.展开更多
基金supported by Defence Innovative Research Program(DIRP)Grant(PA No.9015102335)from Defence Research&Technology Office,Ministry of Defence,Singapore。
文摘Background:Excessive heat exposure can lead to hyperthermia in humans,which impairs physical performance and disrupts cognitive function.While heat is a known physiological stressor,it is unclear how severe heat stress affects brain physiology and function.Methods:Eleven healthy participants were subjected to heat stress from prolonged exercise or warm water immersion until their rectal temperatures(T_(re))attained 39.5℃,inducing exertional or passive hyperthermia,respectively.In a separate trial,blended ice was ingested before and during exercise as a cooling strategy.Data were compared to a control condition with seated rest(normothermic).Brain temperature(T_(br)),cerebral perfusion,and task-based brain activity were assessed using magnetic resonance imaging techniques.Results:T_(br)in motor cortex was found to be tightly regulated at rest(37.3℃±0.4℃(mean±SD))despite fluctuations in T_(re).With the development of hyperthermia,T_(br)increases and dovetails with the rising T_(re).Bilateral motor cortical activity was suppressed during high-intensity plantarflexion tasks,implying a reduced central motor drive in hyperthermic participants(T_(re)=38.5℃±0.1℃).Global gray matter perfusion and regional perfusion in sensorimotor cortex were reduced with passive hyperthermia.Executive function was poorer under a passive hyperthermic state,and this could relate to compromised visual processing as indicated by the reduced activation of left lateral-occipital cortex.Conversely,ingestion of blended ice before and during exercise alleviated the rise in both T_(re)and T_(bc)and mitigated heat-related neural perturbations.Conclusion:Severe heat exposure elevates T_(br),disrupts motor cortical activity and executive function,and this can lead to impairment of physical and cognitive performance.
基金financial support from National Natural Science Foundation of China(No.:51971111)the National Research Foundation,Prime Minister’s Office,Singapore under its Campus for Research Excellence and Technological Enterprise(CREATE)program+2 种基金the Funding for Outstanding Doctoral Dissertation in NUAA(No.BCXJ17-07)Postgraduate Research&Practice Innovation of Jiangsu Province(KYCX17_0252)the Open Research Fund of Jiangsu Provincial Key Laboratory of Bionic Functional Materials。
文摘Developing a flexible,light-weight and effective electromagnetic(EM)absorber remains challenging despite being on increasing demand as more wearable devices and portable electronics are commercialized.Herein,we report a flexible and lightweight hybrid paper by a facile vacuumfiltration-induced self-assembly process,in which cotton-derived carbon fibers serve as flexible skeletons,compactly surrounded by other microwave-attenuating components(reduced graphene oxide and Fe3O4@C nanowires).Owing to its unique architecture and synergy of the three components,the asprepared hybrid paper exhibits flexible and lightweight features as well as superb microwave absorption performance.Maximum absorption intensity with reflection loss as low as-63 dB can be achieved,and its broadest frequency absorption bandwidth of 5.8 GHz almost covers the entire Ku band.Such a hybrid paper is promising to cope with ever-increasing EM interference.The work also paves the way to develop low-cost and flexible EM wave absorber from biomass through a facile method.
基金conducted by Nanomaterials for Energy and Energy-Water Nexus(NEW)Programme under Singapore-HUJ Alliance for Research and Enterprise(SHARE)in the Campus for Research Excellence and Technological Enterprise(CREATE)that is supported by the National Research Foundation,Prime Minister’s O ce,Singaporesupported also by the Israel National Research Center for Electrochemical Propulsion(INREP)。
文摘Lithium-sulfur batteries(LSBs)are considered as the next generation of advanced rechargeable batteries because of their high energy density.In this study,sulfur and CoxS electrocatalyst are deposited on carbon nanotube buckypaper(S/CoxS/BP)by a facile electrodeposition method and are used as a binder-free high-performance cathode for LSBs.Elemental sulfur is deposited on buckypaper by electrooxidation of a polysulfide solution(-S6^2-).This approach substantially increased the current and time efficiency of sulfur electrochemical deposition on conductive material for LSBs.S/CoxS/BP cathode could deliver an initial discharge capacity as high as 1650 mAh g^-1 at 0.1 C,which is close to the theoretical capacity of sulfur.At current rate of 0.5 C,the S/CoxS/BP has a capacity of 1420 mAh g^-1 at the first cycle and 715 mAh g^-1 after 500 cycles with a fading rate of 0.099%per cycle.The high capacity of S/CoxS/BP is attributed to both the homogeneous dispersion of nanosized sulfur within BP and the presence of CoxS catalyst.The sodium dodecyl sulfate(SDS)pretreatment of BP renders it polarity to bind polysulfides and thus facilitates the good dispersibility of nanosized sulfur within BP.CoxS catalyst accelerates the kinetics of polysulfide conversion and reduces the presence of polysulfide in the cathode,which suppresses the polysulfide diffusion to anode,i.e.,the shuttle effect.The mitigation of the active material loss improves not only the capacity but also the cyclability of S/CoxS/BP.
文摘Carbonate electrolytes are one of the most desirable electrolytes for high-energy lithium-sulfur batteries(LSBs)because of their successful implementation in commercial Li-ion batteries.The low-polysulfide-solubility feature of some carbonate solvents also makes them very promising for overcoming the shuttle effects of LSBs.However,regular sulfur electrodes experience undesired electrochemical mechanisms in carbonate electrolytes due to side reactions.In this study,we report a catalytic redox mechanism of sulfur in propylene carbonate(PC)electrolyte based on a compari-son study.The catalytic mechanism is characterized by the interactions between polysulfides and dual N/O functional groups on the host carbon,which largely prevents side reactions between polysulfides and the carbonate electrolyte.Such a mechanism coupled with the low-polysulfide-solubility feature leads to stable cycling of LSBs in PC electrolyte.Favorable dual N/O functional groups are identified via a density functional theory study.This work provides an alternative route for enabling LSBs in carbonate electrolytes.
基金supported by the Singapore MOE Tier 2 MOE2018-T2-2-027the Singapore National Research Foundation under its Campus for Research Excellence and Technological Enterprise (CREATE) Programme
文摘Electrochemical water splitting consists of two elementary reactions i.e.,hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).Developing robust HER and OER technologies necessitates a molecular picture of reaction mechanism,yet the reactants for water splitting reactions are unfortunately not fully understood.Here we utilize magnetic field to understand proton transport in HER,and hydroxide ion transport in OER,to discuss the possible implications on understanding the reactants for HER and OER.Magnetic field is a known tool for changing the movement of charged species like ions,e.g.the magnetic‐field‐improved Cu^(2+)transportation near the electrode in Cu electrodeposition.However,applying a magnetic field does not affect the HER or OER rate across various pH,which challenges the traditional opinion that charged species(i.e.proton and hydroxide ion)act as the reactant.This anomalous response of HER and OER to magnetic field,and the fact that the transport of proton and hydroxide ion follow Grotthuss mechanism,collectively indicate water may act as the universal reactant for HER and OER across various pH.With the aid of magnetic field,this work serves as an understanding of water might be the reactant in HER and OER,and possibly in other electrocatalysis reactions involving protonation and deprotonation step.A model that simply focuses on the charged species but overlooking the complexity of the whole electrolyte phase where water is the dominant species,may not reasonably reflect the electrochemistry of HER and OER in aqueous electrolyte.
基金The authors appreciate the supports from the National Research Foundation(NRF),Prime Minister’s Office,Singapore,under its Campus for Research Excellence and Technological Enterprise(CREATE)programme.We also acknowledge financial support from the academic research fund AcRF tier 2(M4020246,ARC10/15),Ministry of Education,Singapore.
文摘Tuning and optimization of electronic structures and related reaction energetics are critical toward the rational design of efficient electrocatalysts.Herein,experimental and theoretical calculation demonstrate the originally inert N site within polyaniline(PANI)can be activated for hydrogen evolution by proper d-πinterfacial electronic coupling with metal oxide.As a result,the assynthesized WO3 assemblies@PANI via a facile redox-induced assembly and in situ polymerization,exhibits the electrocatalytic production of hydrogen better than other control samples including W18O49@PANI and most of the reported nobel-metal-free electrocatalysts,with low overpotential of 74 mV at 10 mA·cm−2 and small Tafel slope of 46 mV·dec−1 in 0.5M H2SO4(comparable to commercial Pt/C).The general efficacy of this methodology is also validated by extension to other metal oxides such as MoO3 with similar improvements.
基金financially supported by the NRF Investigatorship (NRFI), Award No. NRF-NRFI2016-05the Campus for Research Excellent and Technological Enterprise (CREATE),National Research Foundation, Prime Minister’s Office, Singapore
文摘Sodium-ion capacitors(SICs)have received increasing interest for grid stationary energy storage application due to their affordability,high power,and energy densities.The major challenge for SICs is to overcome the kinetics imbalance between faradaic anode and nonfaradaic cathode.To boost the Na+reaction kinetics,the present work demonstrated a high-rate MnS-based anode by embedding the MnS nanocrystals into the N,S-co-doped carbon matrix(MnS@NSC).Benefiting from the fast pseudocapacitive Na+storage behavior,the resulting composite exhibits extraordinary rate capability(205.6 mAh g−1 at 10 A g−1)and outstanding cycling stability without notable degradation after 2000 cycles.A prototype SIC was demonstrated using MnS@NSC anode and N-doped porous carbon(NC)cathode;the obtained hybrid SIC device can display a high energy density of 139.8 Wh kg−1 and high power density of 11,500 W kg−1,as well as excellent cyclability with 84.5%capacitance retention after 3000 cycles.The superior electrochemical performance is contributed to downsizing of MnS and encapsulation of conductive N,S-co-doped carbon matrix,which not only promote the Na+and electrons transport,but also buffer the volume variations and maintain the structure integrity during Na+insertion/extraction,enabling its comparable fast reaction kinetics and cyclability with NC cathode.
基金funded by the National Research Foundation,Prime Minister’s Office,Singapore under its Campus for Research Excellence and Technological Enterprise(CREATE)Programme.
文摘This study aims to investigate the significance and biodegradation pathways of PHB-based bioplastic in anaerobic digesters treating food waste,where the reactor performance of changed methane generation,bioplastic biodegradation efficiency,and bioinformatic analysis of functional microbes were emphasized.The results showed that PHB-based plastic film could be partially biodegraded in the food waste digester,and a bioaugmentation use of Alcaligenes Faecalis(AF)and Bacillus Megaterium(BM)was beneficial to largely accelerate the degradation process through a beneficial shift of both the functional bacterial and archaeal species.Microbial community analysis indicated that the major bacterial species belonged to genera Candidatus_Cloacimonas,Rikenellaceae,and Defluviitoga,while the dominant methanogenic archaeal species belonged to genera Methanomassiliicoccus,Methanosarcina,and Methanosaeta.Bioplastic biodegradation analysis suggested that the optimal fractions of AF and BM for PHB-based plastic degradation were 50% AF and 75% BM,respectively,which deserves further optimization and scale-up validation.The finding of this study would contribute to the combined management of PHB-based bioplastic with food waste for clean energy recovery and a greener environment.
基金Project supported by the Guangdong Basic and Applied Basic Research Foundation(2022A1515012578,2019A1515010970)the Guangzhou Municipal Science and Technology Project(201904010030)+2 种基金the National Natural Science Foundation of China(51874143,52066001)the Special Project of Foshan Scientific and Technological Innovation Team(2030032000171,2120001010823)partially supported by the National Research Foundation,Prime Minister’s Office,Singapore under its Campus of ResearchExcellence and Technological Enterprise(CREATE)programme。
文摘LaFe_(11.8)Si_(1.2)/10 wt%Ce_(60)Co_(40) composites were prepared by spark plasma sintering and subsequent diffusion annealing.A novel core-shell structure is observed with the LaFe11.8Si1.2 particles as the core and the(La,Ce)_(2)(Fe,Co,Si)_(17)(2:17)phase as the shell.As diffusion annealing time(t_(a))increases,this core-shell structure is replaced by the formation of the(La,Ce)_(1)(Fe,Co,Si)_(13) phase.Annealing at 1323 K for 12 h results in samples with(-ΔSM)^(max) of 9.30 J/(kg·K)(Δμ0H=2 T),good mechanical properties((σbc)^(max)=402 MPa,ε=4.21%)and thermal conductivity of 8.7 W/(m·K).Thus,bulk composites with excellent comprehensive properties for magnetic refrigeration are obtained in this work.
基金Project supported by the National Natural Science Foundation of China(51874143,51801047)the Natural Science Foundation of Guangdong Province(2017A030313317)Natural Science Foundation of Zhejiang Province(LY20E010002)。
文摘Amorphous Fe78-xRExSi4 Nb5 B12Cu1(RE=Gd,Dy) ribbons with different RE contents were prepared by melt spinning to investigate the effect of heavy rare earth(Gd,Dy) substitution on the hyperfine structure,magnetic properties and magnetocaloric effect.The Curie temperature of RE substituted alloys,hyperfine field and magnetic moments of Fe atoms initially increase up to 1 at% RE content and then decrease monotonously for increasing RE content up to 10 at%.The dependence of magnetic entropy change(-△SM) and refrigeration capacity(RC) of the alloys on RE contents displays the same tendency.The RCAREA values of the alloys substituted with 1 at% Gd and Dy are similar to those of recently reported Fe-based metallic glasses with enhanced RC values compared with those of Gd5 Ge1.9Si2 Fe0.1.Enhanced-△SM and RC values,negligible coercive force and hysteresis commonly make these Fe78-xREx-Si4 Nb5 B12Cu1 amorphous alloys as low-cost candidates for high-temperature magnetic refrigeration.
基金This research was supported by the National Research Foundation,Prime Minister's Office,Singapore,under its Campus for Research Excellence and Technological Enterprise(CREATE)programThe work was partially supported by a Singapore Ministry of Education Tier 1 grant(2019-T1-002-125)and Tier 2 grant(MOE-T2EP10220-0001).
文摘Electrochemically producing formate by oxidizing methanol is a promising way to add value to methanol.Noble metal-based electrocatalysts,which have been extensively studied for the methanol oxidation reaction,can catalyze the complete oxidation of methanol to carbon dioxide,but not the mild oxidation to formate.As a result,exploring efficient and earth-abundant electrocatalysts for formate production from methanol is of interest.Herein,we present the electro-oxidation of methanol to formate,catalyzed by iron-substituted lanthanum cobaltite(LaCo_(1-x)Fe_(x)O_(3)).The Fe/Co ratio in the oxides greatly influences the activity and selectivity.This effect is attributed to the higher affinity of Fe and Co to the two reactants:CH3OH and OH,respectively.Because a balance between these affinities is favored,LaCo_(0.5)Fe_(0.5)O_(3) shows the highest formate production rate,at 24.5 mmol h^(-1) g_(oxide)^(-1),and a relatively high Faradaic efficiency of 44.4%in a series of(LaCo_(1-x)Fe_(x)O_(3))samples(x=0.00,0.25,0.50,0.75,1.00)at 1.6 V versus a reversible hydrogen electrode.
基金The work was partially supported by the Singapore Ministry of Education Tier 1 Grant(2019-T1-002-125)Dr.S.Sun thanks the funding support from Beijing Natural Science Foundation Program 2212029 and National Natural Science Foundation of China-Youth Science Fund(Grant No.52001009)Dr.Yu thanks the financial support from the National Research Foundation,Prime Minister's Office,Singapore,under its Campus for Research Excellence and Technological Enterprise(CREATE)program。
文摘The evaluation of the intrinsic activity of catalysts is the most basic in searching energy-and cost-efficient catalyst materials for various applications.The accurate determination of the intrinsic activity is essential for identifying efficient catalysts.While a huge number of studies of electrocatalysis for various applications have been reported,the effects of electrode loading on the apparent intrinsic activity obtained experimentally have been rarely discussed.With a high mass loading on the electrode,not all the catalyst surfaces can be electrochemically active because not all the surfaces can be wetted by the electrolyte.The loading also affects the transport of electrons over the electrode as well as the transport of ions in the electrolyte,and thus affects the kinetics.These lead to the derivations of the apparent intrinsic activity from the real intrinsic activity.Herein,for better understanding the derivations,we evaluate and discuss the effects of electrode mass loading using oxygen evolution reaction as an example.
