1-hexene aromatization is a promising technology to convert excess olefin in fluid catalytic cracking(FCC)gasoline to high-value benzene(B),toluene(T),and xylene.Besides,the increasing market demand of xylene has put ...1-hexene aromatization is a promising technology to convert excess olefin in fluid catalytic cracking(FCC)gasoline to high-value benzene(B),toluene(T),and xylene.Besides,the increasing market demand of xylene has put forward higher requirements for new generation of catalyst.For increasing xylene yield in 1-hexene aromatization,the effect of mesopore structure and spatial distribution on product distribution and Zn loading was studied.Catalysts with different mesopore spatial distribution were prepared by post-treatment of parent HZSM-5 zeolite,including NaOH treatment,tetra-propylammonium hydroxide(TPAOH)treatment,and recrystallization.It was found the evenly distributed mesopore mainly prolongs the catalyst lifetime by enhancing diffusion properties but reduces the aromatics selectivity,as a result of damage of micropores close to the catalyst surface.While the selectivity of high-value xylene can be highly promoted when the mesopore is mainly distributed interior the catalyst.Besides,the state of loaded Zn was also affected by mesopores spatial distribution.On the optimized catalyst,the xylene selectivity was enhanced by 12.4%compared with conventional Zn-loaded parent HZSM-5 catalyst at conversion over 99%.It was attributed to the synergy effect of mesopores spatial distribution and optimized acid properties.This work reveals the role of mesopores in different spatial positions of 1-hexene aromatization catalysts in the reaction process and the influence on metal distribution,as well as their synergistic effect two on the improvement of xylene selectivity,which can improve our understanding of catalyst pore structure and be helpful for the rational design of high-efficient catalyst.展开更多
A simulated gasoline consisting of model sulfur compounds of thiophene （C4H4S） and 3-methythiophene （3-MC4H4S） dissolved in n-heptane was tested for the oxidative desulfurization in the hydrogen peroxide （H202） ...A simulated gasoline consisting of model sulfur compounds of thiophene （C4H4S） and 3-methythiophene （3-MC4H4S） dissolved in n-heptane was tested for the oxidative desulfurization in the hydrogen peroxide （H202） and formic acid oxidative system over metal oxide-loaded molecular sieve. The effects of the oxidative system, loaded metal oxides, phase transfer catalyst, the addition of olefin and aromatics on sulfur removal were investigated in details. The results showed that the sulfur removal rate of simulated gasoline in the H202/formic acid system was higher than in other oxidative systems. The cerium oxide-loaded molecular sieve was found very active catalyst for oxidation of simulated gasoline in this system. The sulfur removal rates of C4H4S and 3-MC4H4S were enhanced when phase transfer catalyst （PTC） was added. However, the sulfur removal rate of simulated gasoline was reduced with the addition of olefin and aromatics.展开更多
Hydrotreating of vacuum residue by ebullated-bed shows tremendous significance due to more stringent environmental regulations and growing demand for lighter fuels. However, enhancing the catalyst stability still rema...Hydrotreating of vacuum residue by ebullated-bed shows tremendous significance due to more stringent environmental regulations and growing demand for lighter fuels. However, enhancing the catalyst stability still remains as a challenging task. Herein, two Ni–Mo/Al_(2)O_(3) catalysts with distinct morphologies(i.e., spherical and cylindrical) were first designed, and the morphology effect on deactivation was systematically elucidated employing multi-characterizations, such as HRTEM with EDX mapping, electron microprobe analysis, FT-IR, TGA and Raman. It is found that spherical catalyst exhibits superior hydrotreating stability over 1600 h. The carbonaceous deposits on spherical catalyst with less graphite structure are lighter, and the coke weight is also smaller. In addition, the metal deposits uniformly distribute in the spherical catalyst, which is better than the concentrated distribution near the pore mouth for the cylindrical catalyst. Furthermore, the intrinsic reason for the differences was analyzed by the bed expansion experiment. Higher bed expansion rate together with the better mass transfer ability leads to the enhanced performance. This work sheds new light on the design of more efficient industrial hydrotreating catalyst based on morphology effect.展开更多
Thiophene C4H4S and 3-methylthiophene3-MC4H4S are typical thiophenenic sulfur compounds that exist in fluid catalytic cracking FCC gasoline. Oxidation of C4H4S and 3-MC4H4S were conducted in hydrogen peroxide H2O2 and...Thiophene C4H4S and 3-methylthiophene3-MC4H4S are typical thiophenenic sulfur compounds that exist in fluid catalytic cracking FCC gasoline. Oxidation of C4H4S and 3-MC4H4S were conducted in hydrogen peroxide H2O2 and formic acid system over a series of silica gel loaded with metal oxide. The silica gel loaded with copper and cobalt 1:1 oxide was found very active for the model compound oxidation using H2O2formic acid, while the silica gel unloaded with metal oxide was less active. The sulfur removal rate of thiophenes was dif- ferent as solvent was changed. And the conversation of C4H4S and 3-MC4H4S was improved at higher temperature, but reduced when olefin was added. The sulfur removal rate of model sulfur compounds was enhanced when the phase transfer catalyst emulsifier polyethylene glycol octyl phenyl ether or tetrabutylammonium bromideTBAB was added. The sulfur removal rate of simulated gasoline containing 524μg·ml-1 sulfur reached 90%. Interestingly, in a H2O2 and formic acid system with the addition of TBAB, a bromine substitution trend appeared in the oxidation of thiophenes, suggesting the influence of TBAB.展开更多
Research on nanofluids has progressed rapidly since its enhanced thermal conductivity was first reported about a decade ago, though much controversy and inconsistency have been reported, and insufficient understanding...Research on nanofluids has progressed rapidly since its enhanced thermal conductivity was first reported about a decade ago, though much controversy and inconsistency have been reported, and insufficient understanding of the formulation and mechanism of nanofluids further limits their applications. This work presents a critical review of research on heat transfer applications of nanofluids with the aim of identifying the limiting factors so as to push forward their further development.展开更多
The TSR process may be one of the reasons to result in the natural gas destruction in deep carbonate reservoirs. The work on this field has been the subject of much research in recent years. In this paper, thermal sim...The TSR process may be one of the reasons to result in the natural gas destruction in deep carbonate reservoirs. The work on this field has been the subject of much research in recent years. In this paper, thermal simulation experiments on the reaction of CH4-CaSO4 were carried out using autoclave at high temperature and high pressure. The products were charac-terized by some advanced analytical methods. The thermodynamics and kinetics were discussed and the reaction mechanism was investigated tentatively. It is found that the reaction can pro-ceed spontaneously to produce H2S, H2O and CaCO3 as the main products at the temperature range of 550―700℃ . The activation energy and geological reaction rate calculated from the ki-netic model can be compared with those from previous work. The results obtained in this paper can provide important information on the explanation of geochemical depth limit for natural gas and on the exploration of gas reservoirs.展开更多
The Speziale,Sarkar and Gatski Reynolds Stress Model(SSG RSM)is utilized to simulate the fluid dynamics in a full baffled stirred tank with a Rushton turbine impeller.Four levels of grid resolutions are chosen to dete...The Speziale,Sarkar and Gatski Reynolds Stress Model(SSG RSM)is utilized to simulate the fluid dynamics in a full baffled stirred tank with a Rushton turbine impeller.Four levels of grid resolutions are chosen to determine an optimised number of grids for further simulations.CFD model data in terms of the flow field,trailing vortex,and the power number are compared with published experimental results.The comparison shows that the global fluid dynamics throughout the stirred tank and the local characteristics of trailing vortices near the blade tips can be captured by the SSG RSM.The predicted mean velocity components in axial,radial and tangential direction are also in good agreement with experiment data.The power number predicted is quite close to the designed value,which demonstrates that this model can accurately calculate the power number in the stirred tank.Therefore,the simulation by using a combination of SSG RSM and MRF impeller rotational model can accurately model turbulent fluid flow in the stirred tank,and it offers an alternative method for design and optimisation of stirred tanks.展开更多
Nanostructured materials afford a promising potential for many energy storage applications because of their extraordinary electrochemical properties.However,the remarkable electrochemical energy storage performance co...Nanostructured materials afford a promising potential for many energy storage applications because of their extraordinary electrochemical properties.However,the remarkable electrochemical energy storage performance could only be harvested at a relatively low mass-loading via the traditional electrode fabrication process,and the scale of these materials into commercial-level mass-loading remains a daunting challenge because the ion diffusion kinetics deteriorates rapidly along with the increased thickness of the electrodes.Very recently,three-dimensional(3D)printing,a promising additive manufacturing technology,has been considered as an emerging method to address the aforementioned issues where the 3D printed electrodes could possess elaborately regulated architectures and rationally organized porosity.As a result,the outstanding electrochemical performance has been widely observed in energy storage devices made of 3D printed electrodes of high-mass loading.In this review,we systemically introduce the basic working principles of various 3D printing technologies and their practical applications to manufacture highmass loading electrodes for energy storage devices.Challenges and perspectives in 3D printing technologies for the construction of electrodes at the current stage are also outlined,aiming to offer some useful opinions for further development for this prosperous field.展开更多
Electrochemical energy storage devices are pivotal in achieving“carbon neutrality”by enabling the storage of energy generated from renewable sources.To facilitate the development of these devices,it is important to ...Electrochemical energy storage devices are pivotal in achieving“carbon neutrality”by enabling the storage of energy generated from renewable sources.To facilitate the development of these devices,it is important to gain insight into the underlying the single-/multi-electron transfer process.This can be achieved through in-time detection under operational conditions,but there are limited tools available for monitoring electron transfer under operando conditions.Electron paramagnetic resonance(EPR)is a powerful technique that can meet these expectations,as it is highly sensitive to unpaired electrons and can detect changes of paramagnetic centres.Despite the long history of in situ electrochemical EPR research,its potential has been surprisingly underutilized due to the need for strict operando cell design under special testing conditions.This review comprehensively summarizes recent efforts to understand energy storage mechanisms using in situ/operando EPR,with the aim of drawing researchers’attention to this powerful technique.After introducing the fundamental principles of EPR,we describe the critical advances made in detecting batteries using operando EPR,along with the remaining challenges and opportunities for future development of this technology in batteries.We emphasize the need for strict operando cell design and the importance of designing experiments that closely mimic real-world conditions.We believe that this review will provide innovative solutions to solve tough problems that researchers may encounter during their battery research,and ultimately contribute to the development of more efficient and sustainable energy storage devices.展开更多
Nowadays,the chemical recycling is applied for only 1%of total waste plastics,largely due to contaminants in plastic waste and difficulty in product control.As the major contaminant,polyvinyl chloride(PVC)often forms ...Nowadays,the chemical recycling is applied for only 1%of total waste plastics,largely due to contaminants in plastic waste and difficulty in product control.As the major contaminant,polyvinyl chloride(PVC)often forms corrosive hydrogen chloride(HCl)during the chemical recycling,which may cause severe catalyst deactivation and equipment damage.However,the investigation on catalytic pyrolysis(the major route for plastics chemical recycling)of the PVC containing mixed plastics has been rarely reported.Here,catalytic co-pyrolysis of PVC and polyethylene(PE)was studied over an aromatization catalyst,Pt/ZSM-5,since the basic building block aromatics are desired products from plastics chemical recycling.The poisoning effect of PVC vapor on the catalyst stability was explored by collective efforts of thorough product analysis and catalyst characterization.It was found that the HCl evolving from PVC has an autocatalytic effect that promotes the scission of dehydrochlorinated PVC,resulting in the high yield of benzene and acetylene from PVC.On the other hand,the presence of PVC suppressed the aromatics formation from PE,largely due to the poisoning effect of PVC-derived HCl on the Pt/ZSM-5.The deactivation is irreversible as evidenced by the decreased zeolite crystallinity and the loss of strong acid sites that are key to the aromatization,possibly due to the removal of framework Al upon the interaction with HCl.The modification with octadecylphosphonic acid only slightly alleviated the PVC poisoning effect.The insights on the PVC poisoning of zeolite catalysts provided in this work may guide the process design of chemical recycling of PVC containing waste plastics.展开更多
To improve the performance of traditional nucle-ation additives and their compatibility with other additives,as well as to solve complex problems in practical applications,SiO_(2) precursors were reactively grafted in...To improve the performance of traditional nucle-ation additives and their compatibility with other additives,as well as to solve complex problems in practical applications,SiO_(2) precursors were reactively grafted in situ with the sym-metrical hydroxyl groups of the nucleation agents.With this approach,the dissymmetrical part of the nucleation agents plays an important role.As a result,the prepared composite additive—the nanoparticle precursor(NPP0)—produces excellent results.The NPP0-PP composite has a transparency of over 93%,haze lower than 15%,and a heat distortion temperature(HDT)of 142℃,which is more than the 110℃ of the pure PP matrix.In addition,it maintains over 90%of the mechanical properties with a deformation coefficient less than 1%.This indicates a strong nanoeffect.展开更多
Facile design of economic-effective hydrogen evolution reaction(HER)catalysts with non-noble materials are promising for the production of renewable chemical fuels.Two-dimensional(2D)ultrathin transition metal dichalc...Facile design of economic-effective hydrogen evolution reaction(HER)catalysts with non-noble materials are promising for the production of renewable chemical fuels.Two-dimensional(2D)ultrathin transition metal dichalcogenides(TMDs)materials with large specific surface area and abundant catalytic active sites can significantly enhance their catalytic activities.Herein,we design and synthesize an atomically thin Ni-Se-S based hybrid nanosheet(NiSe1.2S0.8)via a simple solvothermal method,the thickness of NiSe1.2S0.8 nanosheets is only about 1.1 nm.Benefiting from the ultrathin nanostructure and rich defects,the optimal NiSe1.2S0.8 exhibits good electrocatalytic activity with the overpotential of 144 mV at−10 mA·cm−2,a small Tafel slope of 59 mV·dec−1,and outstanding catalytic stability in acid electrolyte for HER.The theoretical results show that hybrid electrocatalyst by S incorporation possesses the optimal adsorption free energy of hydrogen(ΔGH*).This study provides a simple method to synthesize a highperformance multicomponent electrocatalysts with the ultrathin nanostructures and abundant defects.展开更多
Electrode materials are of decisive importance in determining the performance of electrochemical energy storage(EES)devices.Typically,the electrode materials are physically mixed with polymer binders and conductive ad...Electrode materials are of decisive importance in determining the performance of electrochemical energy storage(EES)devices.Typically,the electrode materials are physically mixed with polymer binders and conductive additives,which are then loaded on the current collectors to function in real devices.Such a configuration inevitably reduces the content of active species and introduces quite some undesired interfaces that bring down the energy densities and power capabilities.One viable solution to address this issue is to construct self-supported electrodes where the active species,for example transition metal oxides(TMOs),are directly integrated with conductive substrates without polymer binders and conductive additives.In this review,the recent progress of self-supported TMO-based electrodes for EES devices including lithium-ion batteries(LIBs),sodium-ion batteries(SIBs),aluminum-ion batteries(AIBs),metal-air batteries,and supercapacitors(SCs),is discussed in great detail.The focused attention is firstly concentrated on their structural design and controllable synthesis.Then,the mechanism understanding of the enhanced electrochemical performance is presented.Finally,the challenges and prospects of self-supported TMO-based electrodes are summarized to end this review.展开更多
基金supported by National Natural Science Foundation of China(22021004).
文摘1-hexene aromatization is a promising technology to convert excess olefin in fluid catalytic cracking(FCC)gasoline to high-value benzene(B),toluene(T),and xylene.Besides,the increasing market demand of xylene has put forward higher requirements for new generation of catalyst.For increasing xylene yield in 1-hexene aromatization,the effect of mesopore structure and spatial distribution on product distribution and Zn loading was studied.Catalysts with different mesopore spatial distribution were prepared by post-treatment of parent HZSM-5 zeolite,including NaOH treatment,tetra-propylammonium hydroxide(TPAOH)treatment,and recrystallization.It was found the evenly distributed mesopore mainly prolongs the catalyst lifetime by enhancing diffusion properties but reduces the aromatics selectivity,as a result of damage of micropores close to the catalyst surface.While the selectivity of high-value xylene can be highly promoted when the mesopore is mainly distributed interior the catalyst.Besides,the state of loaded Zn was also affected by mesopores spatial distribution.On the optimized catalyst,the xylene selectivity was enhanced by 12.4%compared with conventional Zn-loaded parent HZSM-5 catalyst at conversion over 99%.It was attributed to the synergy effect of mesopores spatial distribution and optimized acid properties.This work reveals the role of mesopores in different spatial positions of 1-hexene aromatization catalysts in the reaction process and the influence on metal distribution,as well as their synergistic effect two on the improvement of xylene selectivity,which can improve our understanding of catalyst pore structure and be helpful for the rational design of high-efficient catalyst.
基金Supported by the National Natural Science Foundation of China （No.20276015） and the Natural Science Foundation of Hebei Province （No.203364）.
文摘A simulated gasoline consisting of model sulfur compounds of thiophene （C4H4S） and 3-methythiophene （3-MC4H4S） dissolved in n-heptane was tested for the oxidative desulfurization in the hydrogen peroxide （H202） and formic acid oxidative system over metal oxide-loaded molecular sieve. The effects of the oxidative system, loaded metal oxides, phase transfer catalyst, the addition of olefin and aromatics on sulfur removal were investigated in details. The results showed that the sulfur removal rate of simulated gasoline in the H202/formic acid system was higher than in other oxidative systems. The cerium oxide-loaded molecular sieve was found very active catalyst for oxidation of simulated gasoline in this system. The sulfur removal rates of C4H4S and 3-MC4H4S were enhanced when phase transfer catalyst （PTC） was added. However, the sulfur removal rate of simulated gasoline was reduced with the addition of olefin and aromatics.
基金supported by Natural Science Foundation of China(21978325)the National Key Technologies Research and Development Program of China(2017YFB0306503)+5 种基金Fundamental Research Funds for the Central Universities(18CX02130A,18CX02014A)Open Project of State Key Laboratory of Chemical Engineering(SKL-Ch E-18C04)Doctoral Start-up Foundation of Liaoning Province(2019-BS054)Program for Liaoning Innovative Talents in University(XLYC1807245)China Postdoctoral Science Foundation(2019M661409)High-level Talent Innovation and Business Project of Dalian(2017RQ085)。
文摘Hydrotreating of vacuum residue by ebullated-bed shows tremendous significance due to more stringent environmental regulations and growing demand for lighter fuels. However, enhancing the catalyst stability still remains as a challenging task. Herein, two Ni–Mo/Al_(2)O_(3) catalysts with distinct morphologies(i.e., spherical and cylindrical) were first designed, and the morphology effect on deactivation was systematically elucidated employing multi-characterizations, such as HRTEM with EDX mapping, electron microprobe analysis, FT-IR, TGA and Raman. It is found that spherical catalyst exhibits superior hydrotreating stability over 1600 h. The carbonaceous deposits on spherical catalyst with less graphite structure are lighter, and the coke weight is also smaller. In addition, the metal deposits uniformly distribute in the spherical catalyst, which is better than the concentrated distribution near the pore mouth for the cylindrical catalyst. Furthermore, the intrinsic reason for the differences was analyzed by the bed expansion experiment. Higher bed expansion rate together with the better mass transfer ability leads to the enhanced performance. This work sheds new light on the design of more efficient industrial hydrotreating catalyst based on morphology effect.
基金the National Natural Science Foundation of China (No.20276015) the Natural Science Foundation of HebeiProvince (No.203364)
文摘Thiophene C4H4S and 3-methylthiophene3-MC4H4S are typical thiophenenic sulfur compounds that exist in fluid catalytic cracking FCC gasoline. Oxidation of C4H4S and 3-MC4H4S were conducted in hydrogen peroxide H2O2 and formic acid system over a series of silica gel loaded with metal oxide. The silica gel loaded with copper and cobalt 1:1 oxide was found very active for the model compound oxidation using H2O2formic acid, while the silica gel unloaded with metal oxide was less active. The sulfur removal rate of thiophenes was dif- ferent as solvent was changed. And the conversation of C4H4S and 3-MC4H4S was improved at higher temperature, but reduced when olefin was added. The sulfur removal rate of model sulfur compounds was enhanced when the phase transfer catalyst emulsifier polyethylene glycol octyl phenyl ether or tetrabutylammonium bromideTBAB was added. The sulfur removal rate of simulated gasoline containing 524μg·ml-1 sulfur reached 90%. Interestingly, in a H2O2 and formic acid system with the addition of TBAB, a bromine substitution trend appeared in the oxidation of thiophenes, suggesting the influence of TBAB.
基金EPSRC for financial support (Grant No.:EP/E065449/1)
文摘Research on nanofluids has progressed rapidly since its enhanced thermal conductivity was first reported about a decade ago, though much controversy and inconsistency have been reported, and insufficient understanding of the formulation and mechanism of nanofluids further limits their applications. This work presents a critical review of research on heat transfer applications of nanofluids with the aim of identifying the limiting factors so as to push forward their further development.
基金the National Natural Science Foundation of Chima(Giant No.40172047) the Naional Major Fundamental Research&Development Project(Grant No.G19990433)
文摘The TSR process may be one of the reasons to result in the natural gas destruction in deep carbonate reservoirs. The work on this field has been the subject of much research in recent years. In this paper, thermal simulation experiments on the reaction of CH4-CaSO4 were carried out using autoclave at high temperature and high pressure. The products were charac-terized by some advanced analytical methods. The thermodynamics and kinetics were discussed and the reaction mechanism was investigated tentatively. It is found that the reaction can pro-ceed spontaneously to produce H2S, H2O and CaCO3 as the main products at the temperature range of 550―700℃ . The activation energy and geological reaction rate calculated from the ki-netic model can be compared with those from previous work. The results obtained in this paper can provide important information on the explanation of geochemical depth limit for natural gas and on the exploration of gas reservoirs.
基金support from the Major State Basic Research Development Program of China(973 Program,Grant No.2005CB221205)。
文摘The Speziale,Sarkar and Gatski Reynolds Stress Model(SSG RSM)is utilized to simulate the fluid dynamics in a full baffled stirred tank with a Rushton turbine impeller.Four levels of grid resolutions are chosen to determine an optimised number of grids for further simulations.CFD model data in terms of the flow field,trailing vortex,and the power number are compared with published experimental results.The comparison shows that the global fluid dynamics throughout the stirred tank and the local characteristics of trailing vortices near the blade tips can be captured by the SSG RSM.The predicted mean velocity components in axial,radial and tangential direction are also in good agreement with experiment data.The power number predicted is quite close to the designed value,which demonstrates that this model can accurately calculate the power number in the stirred tank.Therefore,the simulation by using a combination of SSG RSM and MRF impeller rotational model can accurately model turbulent fluid flow in the stirred tank,and it offers an alternative method for design and optimisation of stirred tanks.
基金China Postdoctoral Science Foundation,Grant/Award Number:2020M672166National Natural Science Foundation of China,Grant/Award Numbers:21975287,52002401+4 种基金Natural Science Foundation of Shandong Province,Grant/Award Number:ZR2018ZC1458Taishan Scholar Project of Shandong Province,Grant/Award Number:ts201712020Technological Leading Scholar of 10000 Talent Project,Grant/Award Number:W03020508Shandong Postdoctoral Program for Innovation Talents,Grant/Award Number:sdbX20190032Postdoctoral Applied Research Project of Qingdao,Grant/Award Number:qdyy20110014。
文摘Nanostructured materials afford a promising potential for many energy storage applications because of their extraordinary electrochemical properties.However,the remarkable electrochemical energy storage performance could only be harvested at a relatively low mass-loading via the traditional electrode fabrication process,and the scale of these materials into commercial-level mass-loading remains a daunting challenge because the ion diffusion kinetics deteriorates rapidly along with the increased thickness of the electrodes.Very recently,three-dimensional(3D)printing,a promising additive manufacturing technology,has been considered as an emerging method to address the aforementioned issues where the 3D printed electrodes could possess elaborately regulated architectures and rationally organized porosity.As a result,the outstanding electrochemical performance has been widely observed in energy storage devices made of 3D printed electrodes of high-mass loading.In this review,we systemically introduce the basic working principles of various 3D printing technologies and their practical applications to manufacture highmass loading electrodes for energy storage devices.Challenges and perspectives in 3D printing technologies for the construction of electrodes at the current stage are also outlined,aiming to offer some useful opinions for further development for this prosperous field.
基金the National Natural Science Foundation of China(Nos.22179145,21975287,and 22138013)Taishan Scholars Program of Shandong Province(No.tsqn20221117)+3 种基金the startup support grant from China University of Petroleum(East China)(No.27RA2204027)Shandong Provincial Natural Science Foundation(No.ZR2020ZD08)Shandong Province Postdoctoral Innovative Talent Support Program(No.SDBX2022034)Qingdao Postdoctoral Innovation Project(No.QDBSH20220202003).
文摘Electrochemical energy storage devices are pivotal in achieving“carbon neutrality”by enabling the storage of energy generated from renewable sources.To facilitate the development of these devices,it is important to gain insight into the underlying the single-/multi-electron transfer process.This can be achieved through in-time detection under operational conditions,but there are limited tools available for monitoring electron transfer under operando conditions.Electron paramagnetic resonance(EPR)is a powerful technique that can meet these expectations,as it is highly sensitive to unpaired electrons and can detect changes of paramagnetic centres.Despite the long history of in situ electrochemical EPR research,its potential has been surprisingly underutilized due to the need for strict operando cell design under special testing conditions.This review comprehensively summarizes recent efforts to understand energy storage mechanisms using in situ/operando EPR,with the aim of drawing researchers’attention to this powerful technique.After introducing the fundamental principles of EPR,we describe the critical advances made in detecting batteries using operando EPR,along with the remaining challenges and opportunities for future development of this technology in batteries.We emphasize the need for strict operando cell design and the importance of designing experiments that closely mimic real-world conditions.We believe that this review will provide innovative solutions to solve tough problems that researchers may encounter during their battery research,and ultimately contribute to the development of more efficient and sustainable energy storage devices.
基金supported by the National Natural Science Foundation of China(21991103,21991104,22008074,22378117)the Fundamental Research Funds for the Central Universities。
文摘Nowadays,the chemical recycling is applied for only 1%of total waste plastics,largely due to contaminants in plastic waste and difficulty in product control.As the major contaminant,polyvinyl chloride(PVC)often forms corrosive hydrogen chloride(HCl)during the chemical recycling,which may cause severe catalyst deactivation and equipment damage.However,the investigation on catalytic pyrolysis(the major route for plastics chemical recycling)of the PVC containing mixed plastics has been rarely reported.Here,catalytic co-pyrolysis of PVC and polyethylene(PE)was studied over an aromatization catalyst,Pt/ZSM-5,since the basic building block aromatics are desired products from plastics chemical recycling.The poisoning effect of PVC vapor on the catalyst stability was explored by collective efforts of thorough product analysis and catalyst characterization.It was found that the HCl evolving from PVC has an autocatalytic effect that promotes the scission of dehydrochlorinated PVC,resulting in the high yield of benzene and acetylene from PVC.On the other hand,the presence of PVC suppressed the aromatics formation from PE,largely due to the poisoning effect of PVC-derived HCl on the Pt/ZSM-5.The deactivation is irreversible as evidenced by the decreased zeolite crystallinity and the loss of strong acid sites that are key to the aromatization,possibly due to the removal of framework Al upon the interaction with HCl.The modification with octadecylphosphonic acid only slightly alleviated the PVC poisoning effect.The insights on the PVC poisoning of zeolite catalysts provided in this work may guide the process design of chemical recycling of PVC containing waste plastics.
文摘To improve the performance of traditional nucle-ation additives and their compatibility with other additives,as well as to solve complex problems in practical applications,SiO_(2) precursors were reactively grafted in situ with the sym-metrical hydroxyl groups of the nucleation agents.With this approach,the dissymmetrical part of the nucleation agents plays an important role.As a result,the prepared composite additive—the nanoparticle precursor(NPP0)—produces excellent results.The NPP0-PP composite has a transparency of over 93%,haze lower than 15%,and a heat distortion temperature(HDT)of 142℃,which is more than the 110℃ of the pure PP matrix.In addition,it maintains over 90%of the mechanical properties with a deformation coefficient less than 1%.This indicates a strong nanoeffect.
基金This work was supported by the National Natural Science Foundation of China(Nos.21771191 and 21875285)Taishan Scholar Foundation(No.ts201511019)+1 种基金the Shandong Natural Science Fund(No.ZR2017QB012)the Fundamental Research Funds for the Central Universities(No.19CX05001A).
文摘Facile design of economic-effective hydrogen evolution reaction(HER)catalysts with non-noble materials are promising for the production of renewable chemical fuels.Two-dimensional(2D)ultrathin transition metal dichalcogenides(TMDs)materials with large specific surface area and abundant catalytic active sites can significantly enhance their catalytic activities.Herein,we design and synthesize an atomically thin Ni-Se-S based hybrid nanosheet(NiSe1.2S0.8)via a simple solvothermal method,the thickness of NiSe1.2S0.8 nanosheets is only about 1.1 nm.Benefiting from the ultrathin nanostructure and rich defects,the optimal NiSe1.2S0.8 exhibits good electrocatalytic activity with the overpotential of 144 mV at−10 mA·cm−2,a small Tafel slope of 59 mV·dec−1,and outstanding catalytic stability in acid electrolyte for HER.The theoretical results show that hybrid electrocatalyst by S incorporation possesses the optimal adsorption free energy of hydrogen(ΔGH*).This study provides a simple method to synthesize a highperformance multicomponent electrocatalysts with the ultrathin nanostructures and abundant defects.
基金This work was finally supported by the National Nature Science Foundation of China(Grant No.21975287)the start-up funding support of China University of Petroleum(East China),Taishan Scholar Project(Grant No.ts201712020)+1 种基金Technological Leading Scholar of 10000 Talent Project(Grant No.W03020508)Shandong Provincial Natural Science Foundation(Grant No.ZR2018ZC1458).
文摘Electrode materials are of decisive importance in determining the performance of electrochemical energy storage(EES)devices.Typically,the electrode materials are physically mixed with polymer binders and conductive additives,which are then loaded on the current collectors to function in real devices.Such a configuration inevitably reduces the content of active species and introduces quite some undesired interfaces that bring down the energy densities and power capabilities.One viable solution to address this issue is to construct self-supported electrodes where the active species,for example transition metal oxides(TMOs),are directly integrated with conductive substrates without polymer binders and conductive additives.In this review,the recent progress of self-supported TMO-based electrodes for EES devices including lithium-ion batteries(LIBs),sodium-ion batteries(SIBs),aluminum-ion batteries(AIBs),metal-air batteries,and supercapacitors(SCs),is discussed in great detail.The focused attention is firstly concentrated on their structural design and controllable synthesis.Then,the mechanism understanding of the enhanced electrochemical performance is presented.Finally,the challenges and prospects of self-supported TMO-based electrodes are summarized to end this review.
