CO_(2)injection into geological formations has been proven to be an effective approach for carbon storage.When dissolved in formation water,CO_(2)forms carbonic acid that induces mineral dissolution at pore surfaces u...CO_(2)injection into geological formations has been proven to be an effective approach for carbon storage.When dissolved in formation water,CO_(2)forms carbonic acid that induces mineral dissolution at pore surfaces under acidic conditions.Comprehensive understanding of geochemical interaction between carbonic acid and reservoir rocks is crucial for assessing environmental impact on geological formations.This study focuses on a tight oil sandstone reservoir.After characterizing basic petrophysical properties and mineral composition of rock samples,a series of carbonic acid corrosion experiments with both core and corresponding pure mineral samples were carried out,respectively.Dissolution solutions collected during the experiments were analyzed to examine the variations of ion concentrations in both core and pure mineral solutions.The carbonic acid-pure mineral corrosion kinetics were investigated.The correlations between carbonic acid with core and pure mineral corrosion scenarios were established from the sample mass,reaction rate,and ion concentration.The results show that after corrosion,the mass of calcite and dolomite in the rock sample decreased by 66.7%and 27.3%,respectively.When the corrosion was stabilized,the concentrations of Ca^(2+)and Mg^(2+)in the core solution were 72.9 and 74.4 mg/L.respectively,which was 40.5-41.3 times higher than that of Na+.The reaction kinetics analysis of carbonic acid-rock revealed a two-stage reaction in the pure mineral corrosion process,rapid reaction stage,and slow reaction stage,with different reaction rate constants and reaction orders for each ion.With the correlation between carbonic acid reaction with core and pure minerals,an effective and rapid evaluation method with pure minerals for the carbonic water-rock reaction is established,which costs a shorter time and is easier to investigate.This study provides a simple and faster method to evaluate the carbonic acid corrosion reaction during geological carbon storage.展开更多
It is crucial to understand the mechanism of low temperature CO oxidation reaction catalyzed by gold nanoparticles so as to find out the origin of the high catalytic reactivity and extend the indus‐trialization appli...It is crucial to understand the mechanism of low temperature CO oxidation reaction catalyzed by gold nanoparticles so as to find out the origin of the high catalytic reactivity and extend the indus‐trialization applications of nano gold catalysts. In this work, some theoretical works on CO adsorp‐tion, O2 adsorption, atomic oxygen adsorption, formation of surface gold oxide films, reaction mechanisms of CO oxidation involving O2 reaction with CO and O2 dissociation before reacting with CO on gold surfaces and Au/metal oxide were summarized, and the influences of coordination number, charge transfer and relativity of gold on CO oxidation reaction were briefly reviewed. It was found that CO reaction mechanism depended on the systems with or without oxide and the strong relativistic effects might play an important role in CO oxidation reaction on gold catalysts. In particular, the relativistic effects are related to the unique behaviors of CO adsorption, O adsorption, O2 activation on gold surfaces, effects of coordination number and the wide gap between the chem‐ical inertness of bulk gold and high catalytic activity of nano gold. The present work helps us to understand the CO oxidation reaction mechanism on gold catalysts and the influence of relativistic effects on gold catalysis.展开更多
Using renewable energy to drive carbon dioxide reduction reaction(CO_(2)RR)electrochemically into chemicals with high energy density is an efficient way to achieve carbon neutrality,where the effective utilization of ...Using renewable energy to drive carbon dioxide reduction reaction(CO_(2)RR)electrochemically into chemicals with high energy density is an efficient way to achieve carbon neutrality,where the effective utilization of CO_(2) and the storage of renewable energy are realized.The reactivity and selectivity of CO_(2)RR depend on the structure and composition of the catalyst,applied potential,electrolyte,and pH of the solution.Besides,multiple electron and proton transfer steps are involved in CO_(2)RR,making the reaction pathways even more complicated.In pursuit of molecular-level insights into the CO_(2)RR processes,in situ vibrational methods including infrared,Raman and sum frequency generation spectroscopies have been deployed to monitor the dynamic evolution of catalyst structure,to identify reactive intermediates as well as to investigate the effect of local reaction environment on CO_(2)RR performance.This review summarizes key findings from recent electrochemical vibrational spectrosopic studies of CO_(2)RR in addressing the following issues:the CO_(2)RR mechanisms of different pathways,the role of surface-bound CO species,the compositional and structural effects of catalysts and electrolytes on CO_(2)RR activity and selectivity.Our perspectives on developing high sensitivity wide-frequency infrared spectroscopy,coupling different spectroelectrochemical methods and implementing operando vibrational spectroscopies to tackle the CO_(2)RR process in pilot reactors are offered at the end.展开更多
Electrochemical CO2 reduction reaction(CO2RR)powered by renewable electricity has emerged as the most promising technique for CO2 conversion,making it possible to realize a carbon‐neutral cycle.Highly efficient,robus...Electrochemical CO2 reduction reaction(CO2RR)powered by renewable electricity has emerged as the most promising technique for CO2 conversion,making it possible to realize a carbon‐neutral cycle.Highly efficient,robust,and cost‐effective catalysts are highly demanded for the near‐future practical applications of CO2RR.Previous studies on atomically dispersed metal‐nitrogen(M‐Nx)sites constituted of earth abundant elements with maximum atom‐utilization efficiency have demonstrated their performance towards CO2RR.This review summarizes recent advances on a variety of M‐Nx sites‐containing transition metal‐centered macrocyclic complexes,metal organic frameworks,and M‐Nx‐doped carbon materials for efficient CO2RR,including both experimental and theoretical studies.The roles of metal centers,coordinated ligands,and conductive supports on the intrinsic activity and selectivity,together with the importance of reaction conditions for improved performance are discussed.The mechanisms of CO2RR over these M‐Nx‐containing materials are presented to provide useful guidance for the rational design of efficient catalysts towards CO2RR.展开更多
In the electro-deoxidation process,carbon parasitic reaction(CO_(3)^(2-)+4e–=C+3O^(2-))usually occurs when using carbon materials as the anode,which leads to increase of the carbon content in the final metal and decr...In the electro-deoxidation process,carbon parasitic reaction(CO_(3)^(2-)+4e–=C+3O^(2-))usually occurs when using carbon materials as the anode,which leads to increase of the carbon content in the final metal and decrease of the current efficiency of the process.The aim of this work is to reduce the negative effect of carbon parasitic reaction on the electrolysis process by adjusting anode current density.The results indicate that lower graphite anode area can achieve higher current density,which is helpful to increase the nucleation site of CO_(2) bubbles.Most of CO_(2) would be released from the anode instead of dissolution in the molten CaCl_(2) and reacting with O^(2-)to form CO_(3)^(2-),thus decreasing the carbon parasitic reaction of the process.Furthermore,the results of the compared experiments show that when the anode area decreases from 172.78 to 4.99 cm^(2),CO_(2) concentration in the released gases increases significantly,the carbon mass content in the final metal product decreased from 1.09%to 0.13%,and the current efficiency increased from 6.65%to 36.50%.This study determined a suitable anode current density range for reducing carbon parasitic reaction and provides a valuable reference for the selection of the anode in the electrolysis process.展开更多
We report the synthesis, characterisation and catalytic performance of two nature-inspired biomassderived electro-catalysts for the oxygen reduction reaction in fuel cells. The catalysts were prepared via pyrolysis of...We report the synthesis, characterisation and catalytic performance of two nature-inspired biomassderived electro-catalysts for the oxygen reduction reaction in fuel cells. The catalysts were prepared via pyrolysis of a real food waste（lobster shells） or by mimicking the composition of lobster shells using chitin and CaCO3 particles followed by acid washing. The simplified model of artificial lobster was prepared for better reproducibility. The calcium carbonate in both samples acts as a pore agent, creating increased surface area and pore volume, though considerably higher in artificial lobster samples due to the better homogeneity of the components. Various characterisation techniques revealed the presence of a considerable amount of hydroxyapatite left in the real lobster samples after acid washing and a low content of carbon（23%）, nitrogen and sulphur（〈1%）, limiting the surface area to 23 m^2/g, and consequently resulting in rather poor catalytic activity. However, artificial lobster samples, with a surface area of ≈200 m^2/g and a nitrogen doping of 2%, showed a promising onset potential, very similar to a commercially available platinum catalyst, with better methanol tolerance, though with lower stability in long time testing over 10,000 s.展开更多
Gas-involved electrochemical reactions provide feasible solutions to the worldwide energy crisis and environmental pollution.It has been recognized that various elements of the reaction system,including catalysts,inte...Gas-involved electrochemical reactions provide feasible solutions to the worldwide energy crisis and environmental pollution.It has been recognized that various elements of the reaction system,including catalysts,intermediates,and products,will undergo real-time variations during the reaction process,which are of significant meaning to the in-depth understanding of reaction mechanisms,material structure,and active sites.As judicious tools for real-time monitoring of the changes in these complex elements,in situ techniques have been exposed to the spotlight in recent years.This review aims to highlight significant progress of various advanced in situ characterization techniques,such as in situ X-ray based technologies,in situ spectrum technologies,and in situ scanning probe technologies,that enhance our understanding of heterogeneous electrocatalytic carbon dioxide reduction reaction,nitrogen reduction reaction,and hydrogen evolution reaction.We provide a summary of recent advances in the development and applications of these in situ characterization techniques,from the working principle and detection modes to detailed applications in different reactions,along with key questions that need to be addressed.Finally,in view of the unique application and limitation of different in situ characterization techniques,we conclude by putting forward some insights and perspectives on the development direction and emerging combinations in the future.展开更多
Reasonable control on CRI（coke reaction index）is one of the key factors for BF（blast furnace）low-carbon smelting.However,there are contrary opinions.One is increasing CRI to improve reaction efficiency in BF and t...Reasonable control on CRI（coke reaction index）is one of the key factors for BF（blast furnace）low-carbon smelting.However,there are contrary opinions.One is increasing CRI to improve reaction efficiency in BF and the other is decreasing CRI to suppress coke degradation in furnace.Different methods are adopted to realize effective catalysis（increasing CRI）and passivation（decreasing CRI）of coke.Simulation tests of coke in BF lumpy zone under gradual temperature rising have been done.Effect of CRI on gas composition,ore reduction,burden column permeability and heat reserve zone′s temperature under non-isothermal condition are studied.Then combined with iron making calculations,a novel BF operation suggestion is proposed as coke nut with small size be catalyzed and mixed with ore while skeletal coke with large size be passivated and separately charged into BF.展开更多
The introduction of nitrogen heteroatoms into carbon materials is a facile and efficient strategy to regulate their reactivities and facilitate their potential applications in energy conversion and storage. However,mo...The introduction of nitrogen heteroatoms into carbon materials is a facile and efficient strategy to regulate their reactivities and facilitate their potential applications in energy conversion and storage. However,most of nitrogen heteroatoms are doped into the bulk phase of carbon without site selectivity, which significantly reduces the contacts of feedstocks with the active dopants in a conductive scaffold. Herein we proposed the chemical vapor deposition of a nitrogen-doped graphene skin on the 3D porous graphene framework and donated the carbon/carbon composite as surface N-doped grapheme（SNG）. In contrast with routine N-doped graphene framework（NGF） with bulk distribution of N heteroatoms, the SNG renders a high surface N content of 1.81 at%, enhanced electrical conductivity of 31 S cm^（-1）, a large surface area of 1531 m^2 g^（-1）, a low defect density with a low I_D/I_G ratio of 1.55 calculated from Raman spectrum, and a high oxidation peak of 532.7 ℃ in oxygen atmosphere. The selective distribution of N heteroatoms on the surface of SNG affords the effective exposure of active sites at the interfaces of the electrode/electrolyte, so that more N heteroatoms are able to contact with oxygen feedstocks in oxygen reduction reaction or serve as polysulfide anchoring sites to retard the shuttle of polysulfides in a lithium–sulfur battery. This work opens a fresh viewpoint on the manipulation of active site distribution in a conductive scaffolds for multi-electron redox reaction based energy conversion and storage.展开更多
Excessive emission of carbon dioxide(CO_(2))has posed an imminent threat to human's environment and global prosperity.To achieve a sustainable future,solid oxide electrolysis cell(SOEC),which can efficiently combin...Excessive emission of carbon dioxide(CO_(2))has posed an imminent threat to human's environment and global prosperity.To achieve a sustainable future,solid oxide electrolysis cell(SOEC),which can efficiently combine CO_(2)reduction reaction(CO_(2)RR)and renewable energy storage,has become increasingly attractive owing to its unique functionalities.Additionally,symmetrical SOEC(SSOEC)has been considered as one of the most versatile cell configurations due to its simplified process,high compatibility,and low cost.However,the electrode material requirements become very demanding since efficient catalytic-activities are required for both CO_(2)RR and oxygen evolution reaction(OER).Herein,we demonstrate a novel high-entropy perovskite type symmetrical electrode Pr_(0.5)Ba_(0.5)Mn_(0.2)Fe_(0.2)Co_(0.2)Ni_(0.2)Cu_(0.2)O_(3-δ)(HE-PBM)for SSOEC.B-site doping of transition metals such as Mn,Fe,Co,Ni,and Cu in HE-PBM anode has been found to strongly accelerate the OER in the anode.Moreover,the presence of in-situ formed Fe–Co–Ni–Cu quaternary alloy nanocatalysts from HE-PBM cathode under reducing atmosphere has resulted in superior catalytic-activity towards CO_(2)RR.The faster kinetics are also reflected by the significantly low polarization resistance of 0.289Ω⋅cm^(-2)and high electrolysis current density of 1.21 A⋅cm^(-2)for CO_(2)RR at 2.0 V and 800℃.The excellent electrochemical performance and stability demonstrate that the highentropy perovskite material is a promising electrode material in SSOEC for efficient and durable CO_(2)RR.展开更多
The cyclization reaction of 2-ethynyl-N-sulfonylanilides proceeded efficiently in water with the presence of a catalytic amount of K2CO3 under transition metal-free condition to give indoles in high yields.The recover...The cyclization reaction of 2-ethynyl-N-sulfonylanilides proceeded efficiently in water with the presence of a catalytic amount of K2CO3 under transition metal-free condition to give indoles in high yields.The recovery and reusability of the present catalytic system were investigated.展开更多
Facile synthetic approaches toward the development of efficient and durable nonprecious metal catalysts for the oxygen reduction reaction （ORR） are very important for commercializing advanced electrochemical devices...Facile synthetic approaches toward the development of efficient and durable nonprecious metal catalysts for the oxygen reduction reaction （ORR） are very important for commercializing advanced electrochemical devices such as fuel cells and metal-air batteries. Here we report a novel template approach to synthesize mesoporous Fe-N-doped carbon catalysts encapsulated with Fe3C nanoparticles. In this approach, the layer-structured FeOCI was first used as a template for the synthesis of a three- dimensional polypyrrole （PPy） structure. During the removal of the FeOCI template, the Fe^3＋ can be absorbed by PPy and then converted into Fe3C nanoparticles and Fe-N-C sites during the pyrolyzing process. As a result, the as-prepared catalysts could exhibit superior electrocatalytic ORR performance to the commercial Pt/C catalyst in alkaline solutions. Furthermore, the Zn-air battery assembled using the mesoporous carbon catalyst as the air electrode could surpass the commercial Pt/C catalyst in terms of the power density and energy density.展开更多
Thermochemical sulfate reduction （TSR） is the reaction between anhydrite and petroleum fluids at elevated temperatures to produce H2S and CO2. TSR has been studied in many sedimentary basins such as China＇s Sichuan...Thermochemical sulfate reduction （TSR） is the reaction between anhydrite and petroleum fluids at elevated temperatures to produce H2S and CO2. TSR has been studied in many sedimentary basins such as China＇s Sichuan and Tarim basins because it has a profound impact on the commercial viability of petroleum resources, with HzS typically being undesirable.展开更多
In order to apply lithium hydroxide(LiOH)as a low temperature chemical heat storage material,the carbonation reaction of LiOH and the prevention method are focused in this research.The carbonation of raw LiOH at stora...In order to apply lithium hydroxide(LiOH)as a low temperature chemical heat storage material,the carbonation reaction of LiOH and the prevention method are focused in this research.The carbonation of raw LiOH at storage and hydration condition is experimentally investigated.The results show that the carbonation reaction of LiOH with carbon dioxide(CO_(2))is confirmed during the hydration reaction.The carbonation of LiOH can be easily carried out with CO_(2) at room temperature and humidity.LiOH can be carbonated at a humidity range of 10%to 20%,a normal humidity region that air can easily be reached.Furthermore,the carbonation reaction rate has not nearly affected by the increase of reaction temperature.An improved storage method by storing LiOH at a low humidity less than 1.0%can be effectively prevented the carbonation of LiOH.The hydration reaction ratio of LiOH at the improved storage method shows a better result compared to the ordinary storage method.Therefore,the humidity should be carefully controlled during the storage of LiOH before hydration and dehydration reaction when apply LiOH as a low heat chemical storage material.展开更多
Replacing platinum for catalyzing hydrogen evolution reaction （HER） in acidic medium remains great chal- lenges. Herein, we prepared few-layered MoS2 by ball milling as an efficient catalyst for HER in acidic medium...Replacing platinum for catalyzing hydrogen evolution reaction （HER） in acidic medium remains great chal- lenges. Herein, we prepared few-layered MoS2 by ball milling as an efficient catalyst for HER in acidic medium, The activity of as-prepared MoS2 had a strong dependence on the ball milling time, Furthermore, Ketjen Black EC 300J was added into the ball-milled MoS2 followed by a second ball milling, and the resultant MoS2/carbon black hybrid material showed a much higher HER activity than MoS2 and carbon black alone. The enhanced activity of the MoS2/carbon black hybrid material was attributed to the increased abundance of catalytic edge sites of MoS） and excellent electrical coupling to the underlving carbon network.展开更多
The pore structure of coke under CO2 atmosphere was investigated by the carbon solution-loss reaction experiment.The results show that the pore size distribution of coke gradually changes from dispersion to relative c...The pore structure of coke under CO2 atmosphere was investigated by the carbon solution-loss reaction experiment.The results show that the pore size distribution of coke gradually changes from dispersion to relative concentration with the increase in carbon loss rate,but it tends to be dispersed again in the late stage of the reaction,and the pore volume and specific surface area also increase first and then decrease with the increase in carbon loss rate.Scanning electron microscopy results show that the evolution of coke pores is from the formation of micropores to the expansion of micropores,and finally the micropore and mesopores collapse to form a large number of string holes.The chemical bonds and functional groups of different reacted cokes were analyzed by Fourier-transform infrared spectroscopy.Furthermore,the microstructure of reacted cokes was analyzed by optical microscopy,and then the ordering of the affinity of different microstructures with CO2 was given.The volume hypothesis which was the theory about energy size of comminution was adopted to analyze the degradation behavior of reacted cokes.The breakage energy of reacted cokes was calculated by volume hypothesis,and the power consumption coefficient CK of different reacted cokes was determined by drum experiment,and then the degradation behavior of reacted cokes under different power consumptions was predicted.展开更多
As models of 5, 10-methenyl-tetrahydrofolate coenaymes imidazolinium salts 6a. b were synthesized and their carbon transfer reactions with several types of nucleophiles were studied.
Methyl 3-trimethylsilylpropargyl carbonate reacted with dinucleophiles under the catalysis of palladium(0) complex to give the corresponding desilylated annulation products.
Thermal decomposition of formic acid on SiO2, CeO2 and γ-Al2O3 was studied as an elementary step of reverse water–gas shit reaction（RWGS） over supported Au catalysts. γ-Al2O3 showed the highest CO selectivity amo...Thermal decomposition of formic acid on SiO2, CeO2 and γ-Al2O3 was studied as an elementary step of reverse water–gas shit reaction（RWGS） over supported Au catalysts. γ-Al2O3 showed the highest CO selectivity among the tested oxides in the decomposition of formic acid. Infrared spectroscopy showed the formation of four formate species on γ-Al2O3： three η~1-type and one μ~2-type species, and these formates decomposed to CO at 473 K or higher. Au-loaded γ-Al2O3 samples were prepared by a depositionprecipitation method and used as catalysts for RWGS. The supported Au catalyst gave CO with high selectivity over 99% from CO2 and H2, which is attributed to the formation of formates on Au and subsequent decomposition to CO on γ-Al2O3.展开更多
RuO2 nanoparticles supported on multi-walled carbon nanotubes（CNTs） functionalized with oxygen（OCNTs） and nitrogen（NCNTs） were employed for the oxygen evolution reaction（OER） in 0.1 M KOH.The catalysts were sy...RuO2 nanoparticles supported on multi-walled carbon nanotubes（CNTs） functionalized with oxygen（OCNTs） and nitrogen（NCNTs） were employed for the oxygen evolution reaction（OER） in 0.1 M KOH.The catalysts were synthesized by metal-organic chemical vapor deposition using ruthenium carbonyl（Ru3（CO）（12）） as Ru precursor. The obtained RuO2/OCNT and RuO2/NCNT composites were characterized using TEM, H2-TPR, XRD and XPS in order probe structure–activity correlations, particularly, the effect of the different surface functional groups on the electrochemical OER performance. The electrocatalytic activity and stability of the catalysts with mean RuO2 particle sizes of 13–14 nm was evaluated by linear sweep voltammetry, cyclic voltammetry, and chronopotentiometry, showing that the generation of nitrogen-containing functional groups on CNTs was beneficial for both OER activity and stability. In the presence of RuO2, carbon corrosion was found to be significantly less severe.展开更多
基金the National Natural Science Foundation of China(52474073,52288101,52120105007,51804327)Shandong Provincial Natural Science Foundation(ZR2023ME016)Climb Taishan Scholar Program in Shandong Province(tspd20230605).
文摘CO_(2)injection into geological formations has been proven to be an effective approach for carbon storage.When dissolved in formation water,CO_(2)forms carbonic acid that induces mineral dissolution at pore surfaces under acidic conditions.Comprehensive understanding of geochemical interaction between carbonic acid and reservoir rocks is crucial for assessing environmental impact on geological formations.This study focuses on a tight oil sandstone reservoir.After characterizing basic petrophysical properties and mineral composition of rock samples,a series of carbonic acid corrosion experiments with both core and corresponding pure mineral samples were carried out,respectively.Dissolution solutions collected during the experiments were analyzed to examine the variations of ion concentrations in both core and pure mineral solutions.The carbonic acid-pure mineral corrosion kinetics were investigated.The correlations between carbonic acid with core and pure mineral corrosion scenarios were established from the sample mass,reaction rate,and ion concentration.The results show that after corrosion,the mass of calcite and dolomite in the rock sample decreased by 66.7%and 27.3%,respectively.When the corrosion was stabilized,the concentrations of Ca^(2+)and Mg^(2+)in the core solution were 72.9 and 74.4 mg/L.respectively,which was 40.5-41.3 times higher than that of Na+.The reaction kinetics analysis of carbonic acid-rock revealed a two-stage reaction in the pure mineral corrosion process,rapid reaction stage,and slow reaction stage,with different reaction rate constants and reaction orders for each ion.With the correlation between carbonic acid reaction with core and pure minerals,an effective and rapid evaluation method with pure minerals for the carbonic water-rock reaction is established,which costs a shorter time and is easier to investigate.This study provides a simple and faster method to evaluate the carbonic acid corrosion reaction during geological carbon storage.
基金supported by the National Natural Science Foundation of China (21103165)
文摘It is crucial to understand the mechanism of low temperature CO oxidation reaction catalyzed by gold nanoparticles so as to find out the origin of the high catalytic reactivity and extend the indus‐trialization applications of nano gold catalysts. In this work, some theoretical works on CO adsorp‐tion, O2 adsorption, atomic oxygen adsorption, formation of surface gold oxide films, reaction mechanisms of CO oxidation involving O2 reaction with CO and O2 dissociation before reacting with CO on gold surfaces and Au/metal oxide were summarized, and the influences of coordination number, charge transfer and relativity of gold on CO oxidation reaction were briefly reviewed. It was found that CO reaction mechanism depended on the systems with or without oxide and the strong relativistic effects might play an important role in CO oxidation reaction on gold catalysts. In particular, the relativistic effects are related to the unique behaviors of CO adsorption, O adsorption, O2 activation on gold surfaces, effects of coordination number and the wide gap between the chem‐ical inertness of bulk gold and high catalytic activity of nano gold. The present work helps us to understand the CO oxidation reaction mechanism on gold catalysts and the influence of relativistic effects on gold catalysis.
文摘Using renewable energy to drive carbon dioxide reduction reaction(CO_(2)RR)electrochemically into chemicals with high energy density is an efficient way to achieve carbon neutrality,where the effective utilization of CO_(2) and the storage of renewable energy are realized.The reactivity and selectivity of CO_(2)RR depend on the structure and composition of the catalyst,applied potential,electrolyte,and pH of the solution.Besides,multiple electron and proton transfer steps are involved in CO_(2)RR,making the reaction pathways even more complicated.In pursuit of molecular-level insights into the CO_(2)RR processes,in situ vibrational methods including infrared,Raman and sum frequency generation spectroscopies have been deployed to monitor the dynamic evolution of catalyst structure,to identify reactive intermediates as well as to investigate the effect of local reaction environment on CO_(2)RR performance.This review summarizes key findings from recent electrochemical vibrational spectrosopic studies of CO_(2)RR in addressing the following issues:the CO_(2)RR mechanisms of different pathways,the role of surface-bound CO species,the compositional and structural effects of catalysts and electrolytes on CO_(2)RR activity and selectivity.Our perspectives on developing high sensitivity wide-frequency infrared spectroscopy,coupling different spectroelectrochemical methods and implementing operando vibrational spectroscopies to tackle the CO_(2)RR process in pilot reactors are offered at the end.
基金supported by the National Key R&D Program of China(2017YFA0700102)the National Natural Science Foundation of China(21573222 and 91545202)+1 种基金the Outstanding Youth Talent Project of Dalian(2017RJ03)the DMTO Project of Dalian Institute of Chemical Physics,CAS(DICP DMTO201702),the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB17020200),the Youth Innovation Promotion Association,CAS(2015145)~~
文摘Electrochemical CO2 reduction reaction(CO2RR)powered by renewable electricity has emerged as the most promising technique for CO2 conversion,making it possible to realize a carbon‐neutral cycle.Highly efficient,robust,and cost‐effective catalysts are highly demanded for the near‐future practical applications of CO2RR.Previous studies on atomically dispersed metal‐nitrogen(M‐Nx)sites constituted of earth abundant elements with maximum atom‐utilization efficiency have demonstrated their performance towards CO2RR.This review summarizes recent advances on a variety of M‐Nx sites‐containing transition metal‐centered macrocyclic complexes,metal organic frameworks,and M‐Nx‐doped carbon materials for efficient CO2RR,including both experimental and theoretical studies.The roles of metal centers,coordinated ligands,and conductive supports on the intrinsic activity and selectivity,together with the importance of reaction conditions for improved performance are discussed.The mechanisms of CO2RR over these M‐Nx‐containing materials are presented to provide useful guidance for the rational design of efficient catalysts towards CO2RR.
基金the National Natural Science Foundation of China(51674054)supported by the Chongqing Key Laboratory of Vanadium-Titanium Metallurgy and New Materials,Chongqing University,China.
文摘In the electro-deoxidation process,carbon parasitic reaction(CO_(3)^(2-)+4e–=C+3O^(2-))usually occurs when using carbon materials as the anode,which leads to increase of the carbon content in the final metal and decrease of the current efficiency of the process.The aim of this work is to reduce the negative effect of carbon parasitic reaction on the electrolysis process by adjusting anode current density.The results indicate that lower graphite anode area can achieve higher current density,which is helpful to increase the nucleation site of CO_(2) bubbles.Most of CO_(2) would be released from the anode instead of dissolution in the molten CaCl_(2) and reacting with O^(2-)to form CO_(3)^(2-),thus decreasing the carbon parasitic reaction of the process.Furthermore,the results of the compared experiments show that when the anode area decreases from 172.78 to 4.99 cm^(2),CO_(2) concentration in the released gases increases significantly,the carbon mass content in the final metal product decreased from 1.09%to 0.13%,and the current efficiency increased from 6.65%to 36.50%.This study determined a suitable anode current density range for reducing carbon parasitic reaction and provides a valuable reference for the selection of the anode in the electrolysis process.
基金the EU for the Intra European Marie Curie Research Fellowship (PIEFGA-2013-623227)
文摘We report the synthesis, characterisation and catalytic performance of two nature-inspired biomassderived electro-catalysts for the oxygen reduction reaction in fuel cells. The catalysts were prepared via pyrolysis of a real food waste（lobster shells） or by mimicking the composition of lobster shells using chitin and CaCO3 particles followed by acid washing. The simplified model of artificial lobster was prepared for better reproducibility. The calcium carbonate in both samples acts as a pore agent, creating increased surface area and pore volume, though considerably higher in artificial lobster samples due to the better homogeneity of the components. Various characterisation techniques revealed the presence of a considerable amount of hydroxyapatite left in the real lobster samples after acid washing and a low content of carbon（23%）, nitrogen and sulphur（〈1%）, limiting the surface area to 23 m^2/g, and consequently resulting in rather poor catalytic activity. However, artificial lobster samples, with a surface area of ≈200 m^2/g and a nitrogen doping of 2%, showed a promising onset potential, very similar to a commercially available platinum catalyst, with better methanol tolerance, though with lower stability in long time testing over 10,000 s.
基金supported by The National Natural Science Foundation of China(Nos.U21A20332,52103226,and 52071226)The Outstanding Youth Foundation of Jiangsu Province(No.BK20220061)+2 种基金The Natural Science Foundation of Jiangsu Province(No.BK20201171)The Key Research and Development Plan of Jiangsu Province(No.BE2020003-3)The Fellowship of China Postdoctoral Science Foundation(No.2021M702382).
文摘Gas-involved electrochemical reactions provide feasible solutions to the worldwide energy crisis and environmental pollution.It has been recognized that various elements of the reaction system,including catalysts,intermediates,and products,will undergo real-time variations during the reaction process,which are of significant meaning to the in-depth understanding of reaction mechanisms,material structure,and active sites.As judicious tools for real-time monitoring of the changes in these complex elements,in situ techniques have been exposed to the spotlight in recent years.This review aims to highlight significant progress of various advanced in situ characterization techniques,such as in situ X-ray based technologies,in situ spectrum technologies,and in situ scanning probe technologies,that enhance our understanding of heterogeneous electrocatalytic carbon dioxide reduction reaction,nitrogen reduction reaction,and hydrogen evolution reaction.We provide a summary of recent advances in the development and applications of these in situ characterization techniques,from the working principle and detection modes to detailed applications in different reactions,along with key questions that need to be addressed.Finally,in view of the unique application and limitation of different in situ characterization techniques,we conclude by putting forward some insights and perspectives on the development direction and emerging combinations in the future.
基金Sponsored by National Natural Science Foundation of China(61271303)Fundamental Research Funds for CentralUniversities of China(FRF-TP-12-029A)
文摘Reasonable control on CRI（coke reaction index）is one of the key factors for BF（blast furnace）low-carbon smelting.However,there are contrary opinions.One is increasing CRI to improve reaction efficiency in BF and the other is decreasing CRI to suppress coke degradation in furnace.Different methods are adopted to realize effective catalysis（increasing CRI）and passivation（decreasing CRI）of coke.Simulation tests of coke in BF lumpy zone under gradual temperature rising have been done.Effect of CRI on gas composition,ore reduction,burden column permeability and heat reserve zone′s temperature under non-isothermal condition are studied.Then combined with iron making calculations,a novel BF operation suggestion is proposed as coke nut with small size be catalyzed and mixed with ore while skeletal coke with large size be passivated and separately charged into BF.
基金supported by the National Key Research and Development Program(2016YFA0202500 and 2016YFA0200102)the Natural Scientific Foundation of China(21776019)
文摘The introduction of nitrogen heteroatoms into carbon materials is a facile and efficient strategy to regulate their reactivities and facilitate their potential applications in energy conversion and storage. However,most of nitrogen heteroatoms are doped into the bulk phase of carbon without site selectivity, which significantly reduces the contacts of feedstocks with the active dopants in a conductive scaffold. Herein we proposed the chemical vapor deposition of a nitrogen-doped graphene skin on the 3D porous graphene framework and donated the carbon/carbon composite as surface N-doped grapheme（SNG）. In contrast with routine N-doped graphene framework（NGF） with bulk distribution of N heteroatoms, the SNG renders a high surface N content of 1.81 at%, enhanced electrical conductivity of 31 S cm^（-1）, a large surface area of 1531 m^2 g^（-1）, a low defect density with a low I_D/I_G ratio of 1.55 calculated from Raman spectrum, and a high oxidation peak of 532.7 ℃ in oxygen atmosphere. The selective distribution of N heteroatoms on the surface of SNG affords the effective exposure of active sites at the interfaces of the electrode/electrolyte, so that more N heteroatoms are able to contact with oxygen feedstocks in oxygen reduction reaction or serve as polysulfide anchoring sites to retard the shuttle of polysulfides in a lithium–sulfur battery. This work opens a fresh viewpoint on the manipulation of active site distribution in a conductive scaffolds for multi-electron redox reaction based energy conversion and storage.
基金supported by National Natural Science Foundation of China(U21A20317),the National Key Research and Development Program of China(2022YFA1504701)the Fundamental Research Funds for the Central University(2042022gf0002)the U.S.National Science Foundation(1832809)and the start-up research funds from Wuhan Institute of Technology(K202201).
文摘Excessive emission of carbon dioxide(CO_(2))has posed an imminent threat to human's environment and global prosperity.To achieve a sustainable future,solid oxide electrolysis cell(SOEC),which can efficiently combine CO_(2)reduction reaction(CO_(2)RR)and renewable energy storage,has become increasingly attractive owing to its unique functionalities.Additionally,symmetrical SOEC(SSOEC)has been considered as one of the most versatile cell configurations due to its simplified process,high compatibility,and low cost.However,the electrode material requirements become very demanding since efficient catalytic-activities are required for both CO_(2)RR and oxygen evolution reaction(OER).Herein,we demonstrate a novel high-entropy perovskite type symmetrical electrode Pr_(0.5)Ba_(0.5)Mn_(0.2)Fe_(0.2)Co_(0.2)Ni_(0.2)Cu_(0.2)O_(3-δ)(HE-PBM)for SSOEC.B-site doping of transition metals such as Mn,Fe,Co,Ni,and Cu in HE-PBM anode has been found to strongly accelerate the OER in the anode.Moreover,the presence of in-situ formed Fe–Co–Ni–Cu quaternary alloy nanocatalysts from HE-PBM cathode under reducing atmosphere has resulted in superior catalytic-activity towards CO_(2)RR.The faster kinetics are also reflected by the significantly low polarization resistance of 0.289Ω⋅cm^(-2)and high electrolysis current density of 1.21 A⋅cm^(-2)for CO_(2)RR at 2.0 V and 800℃.The excellent electrochemical performance and stability demonstrate that the highentropy perovskite material is a promising electrode material in SSOEC for efficient and durable CO_(2)RR.
基金supported by the National Natural Science Foundation of China (No. 21402137)Xinmiao Talents Program of Zhejiang Province (No. 2016R430021)
文摘The cyclization reaction of 2-ethynyl-N-sulfonylanilides proceeded efficiently in water with the presence of a catalytic amount of K2CO3 under transition metal-free condition to give indoles in high yields.The recovery and reusability of the present catalytic system were investigated.
基金supported by the National Key Basic Research Program of China (No. 2015CB351903)National Natural Science Foundation of China (No. 51402282)+1 种基金China Postdoctoral Science Foundation (No. 2016M590579)the Fundamental Research Funds for the Central Universities
文摘Facile synthetic approaches toward the development of efficient and durable nonprecious metal catalysts for the oxygen reduction reaction （ORR） are very important for commercializing advanced electrochemical devices such as fuel cells and metal-air batteries. Here we report a novel template approach to synthesize mesoporous Fe-N-doped carbon catalysts encapsulated with Fe3C nanoparticles. In this approach, the layer-structured FeOCI was first used as a template for the synthesis of a three- dimensional polypyrrole （PPy） structure. During the removal of the FeOCI template, the Fe^3＋ can be absorbed by PPy and then converted into Fe3C nanoparticles and Fe-N-C sites during the pyrolyzing process. As a result, the as-prepared catalysts could exhibit superior electrocatalytic ORR performance to the commercial Pt/C catalyst in alkaline solutions. Furthermore, the Zn-air battery assembled using the mesoporous carbon catalyst as the air electrode could surpass the commercial Pt/C catalyst in terms of the power density and energy density.
基金supported by the National Natural Science Foundation of China(grant No.41530314)Geological Survey Program(grant No.1212291313016001)
文摘Thermochemical sulfate reduction （TSR） is the reaction between anhydrite and petroleum fluids at elevated temperatures to produce H2S and CO2. TSR has been studied in many sedimentary basins such as China＇s Sichuan and Tarim basins because it has a profound impact on the commercial viability of petroleum resources, with HzS typically being undesirable.
基金This work was supported by“Knowledge Hub Aichi,”Priority Research Project from Aichi Prefectural Government,Japan,Leading Key Projects of Chinese Academy of Sciences(No.QYZDYSSW-JSC038)Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory,Guangzhou(GML2019ZD0108)Science and Technology Planning Project of Guangdong Province,China(No.2017A050501046).
文摘In order to apply lithium hydroxide(LiOH)as a low temperature chemical heat storage material,the carbonation reaction of LiOH and the prevention method are focused in this research.The carbonation of raw LiOH at storage and hydration condition is experimentally investigated.The results show that the carbonation reaction of LiOH with carbon dioxide(CO_(2))is confirmed during the hydration reaction.The carbonation of LiOH can be easily carried out with CO_(2) at room temperature and humidity.LiOH can be carbonated at a humidity range of 10%to 20%,a normal humidity region that air can easily be reached.Furthermore,the carbonation reaction rate has not nearly affected by the increase of reaction temperature.An improved storage method by storing LiOH at a low humidity less than 1.0%can be effectively prevented the carbonation of LiOH.The hydration reaction ratio of LiOH at the improved storage method shows a better result compared to the ordinary storage method.Therefore,the humidity should be carefully controlled during the storage of LiOH before hydration and dehydration reaction when apply LiOH as a low heat chemical storage material.
基金the financial support from the Ministry of Science and Technology of China (grants 2012CB215500 and 2013CB933100)the National Natural Science Foundation of China (grants 21573222 and 21103178)
文摘Replacing platinum for catalyzing hydrogen evolution reaction （HER） in acidic medium remains great chal- lenges. Herein, we prepared few-layered MoS2 by ball milling as an efficient catalyst for HER in acidic medium, The activity of as-prepared MoS2 had a strong dependence on the ball milling time, Furthermore, Ketjen Black EC 300J was added into the ball-milled MoS2 followed by a second ball milling, and the resultant MoS2/carbon black hybrid material showed a much higher HER activity than MoS2 and carbon black alone. The enhanced activity of the MoS2/carbon black hybrid material was attributed to the increased abundance of catalytic edge sites of MoS） and excellent electrical coupling to the underlving carbon network.
基金The authors would like to express their thanks for the support to this work by National Natural Science Foundation of China(51604208)Special Project of Shaanxi Provincial Department of Education(17JK0458)Natural Science Foundation of Shaanxi Province(2019JLM-34,2019JLP-15).
文摘The pore structure of coke under CO2 atmosphere was investigated by the carbon solution-loss reaction experiment.The results show that the pore size distribution of coke gradually changes from dispersion to relative concentration with the increase in carbon loss rate,but it tends to be dispersed again in the late stage of the reaction,and the pore volume and specific surface area also increase first and then decrease with the increase in carbon loss rate.Scanning electron microscopy results show that the evolution of coke pores is from the formation of micropores to the expansion of micropores,and finally the micropore and mesopores collapse to form a large number of string holes.The chemical bonds and functional groups of different reacted cokes were analyzed by Fourier-transform infrared spectroscopy.Furthermore,the microstructure of reacted cokes was analyzed by optical microscopy,and then the ordering of the affinity of different microstructures with CO2 was given.The volume hypothesis which was the theory about energy size of comminution was adopted to analyze the degradation behavior of reacted cokes.The breakage energy of reacted cokes was calculated by volume hypothesis,and the power consumption coefficient CK of different reacted cokes was determined by drum experiment,and then the degradation behavior of reacted cokes under different power consumptions was predicted.
基金This work was supported by the National Natural Science Foundation of China and Shanxi Natural Science Foundation
文摘As models of 5, 10-methenyl-tetrahydrofolate coenaymes imidazolinium salts 6a. b were synthesized and their carbon transfer reactions with several types of nucleophiles were studied.
文摘Methyl 3-trimethylsilylpropargyl carbonate reacted with dinucleophiles under the catalysis of palladium(0) complex to give the corresponding desilylated annulation products.
文摘Thermal decomposition of formic acid on SiO2, CeO2 and γ-Al2O3 was studied as an elementary step of reverse water–gas shit reaction（RWGS） over supported Au catalysts. γ-Al2O3 showed the highest CO selectivity among the tested oxides in the decomposition of formic acid. Infrared spectroscopy showed the formation of four formate species on γ-Al2O3： three η~1-type and one μ~2-type species, and these formates decomposed to CO at 473 K or higher. Au-loaded γ-Al2O3 samples were prepared by a depositionprecipitation method and used as catalysts for RWGS. The supported Au catalyst gave CO with high selectivity over 99% from CO2 and H2, which is attributed to the formation of formates on Au and subsequent decomposition to CO on γ-Al2O3.
基金the IMPRS-Sur Mat of the Max Planck Society for a research grant
文摘RuO2 nanoparticles supported on multi-walled carbon nanotubes（CNTs） functionalized with oxygen（OCNTs） and nitrogen（NCNTs） were employed for the oxygen evolution reaction（OER） in 0.1 M KOH.The catalysts were synthesized by metal-organic chemical vapor deposition using ruthenium carbonyl（Ru3（CO）（12）） as Ru precursor. The obtained RuO2/OCNT and RuO2/NCNT composites were characterized using TEM, H2-TPR, XRD and XPS in order probe structure–activity correlations, particularly, the effect of the different surface functional groups on the electrochemical OER performance. The electrocatalytic activity and stability of the catalysts with mean RuO2 particle sizes of 13–14 nm was evaluated by linear sweep voltammetry, cyclic voltammetry, and chronopotentiometry, showing that the generation of nitrogen-containing functional groups on CNTs was beneficial for both OER activity and stability. In the presence of RuO2, carbon corrosion was found to be significantly less severe.
