Electrochemical carbon dioxide reduction reaction(CO_(2)RR)converts CO_(2) into valuable chemicals by consuming renewable electricity at mild conditions,making it a promising approach to achieving carbon neutrality.Ho...Electrochemical carbon dioxide reduction reaction(CO_(2)RR)converts CO_(2) into valuable chemicals by consuming renewable electricity at mild conditions,making it a promising approach to achieving carbon neutrality.However,the reaction of CO_(2) with hydroxide ions to form carbonates leads to low carbon utilization and energy efficiency in near-neutral or alkaline CO_(2)RR.The high concentration of protons in acidic media can effectively mitigate carbonate formation and deposition,thereby significantly minimizing carbon loss and energy consumption.Unfortunately,hydrogen evolution reaction(HER)is more kinetically favorable than CO_(2)RR in acidic media.Herein,we comprehensively overview recent progress in acidic CO_(2)RR and propose two strategies derived from the competing reaction pathways of HER and CO_(2)RR:one focuses on regulating the H+mass transport,while the other aims to modulate the intrinsic kinetic activity of CO_(2)RR.The two strategies are designed to compete for the limited active sites on the catalyst surface,inhibit side reactions,and enhance the activity and selectivity of CO_(2)RR.The representative approaches include modulating the interface electric field,constructing a local alkaline environment,and regulating competing adsorption sites.Finally,we also review the technical challenges and future perspectives of acidic CO_(2)RR coupled with membrane electrode assemblies(MEAs).展开更多
Hexafluoropropylene oxide(HFPO)is a crucial fluorinated chemical mainly synthesized from hexafluoropropylene(HFP)through the oxidation of oxygen.However,the reaction network and kinetic characteristics are not fully u...Hexafluoropropylene oxide(HFPO)is a crucial fluorinated chemical mainly synthesized from hexafluoropropylene(HFP)through the oxidation of oxygen.However,the reaction network and kinetic characteristics are not fully understood yet,resulting in a lack of theoretical basis for synthesis process improvement.Here,the free radical reaction mechanism and complete reaction network involved in the noncatalytic oxidation of HFP to synthesize HFPO was explored by density functional theory.Transition state theory was employed to calculate the intrinsic reaction rate constants for elementary reactions.Based on theoretical reaction rate ratios,reaction pathways were selected,and a simplified reaction network was derived.It was found that byproducts were formed owing to the decomposition of HFPO and subsequent reactions with excessive oxygen while oxygen tended to participate more in the main reaction under oxygen-deficient conditions.The variations in reaction pathways occurring at different HFP/oxygen molar ratios was well elucidated by comparing with experimental data.This research establishes a robust theoretical foundation for optimizing and regulating the synthesis of HFPO.展开更多
Photosynthesis converts solar energy into chemical energy through highly coordinated photosynthetic reactions.Inspired by natural systems,artificial photosynthesis aims to develop an efficient,sustainable,and cost-eff...Photosynthesis converts solar energy into chemical energy through highly coordinated photosynthetic reactions.Inspired by natural systems,artificial photosynthesis aims to develop an efficient,sustainable,and cost-effective pathway for solar-tochemical conversion.This review examines natural photosynthetic pathways,including retinal/rhodopsin-,bacteriochlorophyll-,and chlorophyll-based systems,highlighting their key components and mechanisms.Next,we outline reaction pathways in artificial photosynthetic systems constructed via heterogeneous,homogeneous,self-assembly,and semi-artificial strategies,focusing on water splitting,carbon fixation,and nitrogen fixation.Finally,we offer insights into future directions for artificial photosynthesis,emphasizing the importance of using self-assembly strategies and the potential of using primitive phototrophic microorganisms as models.展开更多
Hydrogen peroxide(H_(2)O_(2))is a versatile oxidant widely used in pharmaceuticals,environmental protection,and chemical manufacturing.However,conventional H_(2)O_(2)production relies on energy-intensive processes and...Hydrogen peroxide(H_(2)O_(2))is a versatile oxidant widely used in pharmaceuticals,environmental protection,and chemical manufacturing.However,conventional H_(2)O_(2)production relies on energy-intensive processes and costly metal-based catalysts,raising economic and environmental concerns.As a sustainable alternative,photocatalytic H_(2)O_(2)synthesis harnesses solar energy,water,and oxygen under mild conditions.This review summarizes recent advancements in the development of metal-free organic semiconductors for photocatalytic H_(2)O_(2)generation.Notably,it delves into novel surface reaction mechanisms,including anthraquinone(AQ)intermediate,peroxy acid intermediate,bipyridine intermediate,and dual channel synergistic mechanisms for optimizing photocatalyst performance.This review also umderscores the critical role of advanced characterization techniques,including in-situ characterizations and computational simulations,in elucidating structure-property relationships and monitoring real-time catalytic processes.By presenting novel strategies for material modification and exploring potential device-level applications,the review aims to inspire further research and facilitate the industrial implementation of photocatalytic H_(2)O_(2)production,thereby advancing sustainable chemical manufacturing.展开更多
The electrochemical reduction of carbon dioxide(CO_(2))into value-added chemicals and fuels has been extensively studied as a promising strategy for mitigating environmental issues and achieving sustainable energy con...The electrochemical reduction of carbon dioxide(CO_(2))into value-added chemicals and fuels has been extensively studied as a promising strategy for mitigating environmental issues and achieving sustainable energy conversion.Substantial efforts have been made to improve the understanding of CO_(2)reduction reaction(CO_(2)RR)mechanisms by computational and spectroscopic studies.An in-depth understanding of CO_(2)RR mechanism can provide the guidance and criteria for designing high-efficiency catalysts,and hence,steering CO_(2)RR to desired products.This review systematically discusses the formation mechanisms and reaction pathways of various CO_(2)RR products,including C_(1)products(CO,HCOOH,and CH_(4)),C_(2)products(C_(2)H_(4),C_(2)H_(5)OH,and CH_(3)COOH),and C_(3+)products(C_(3)H_(6),C_(3)H_(7)OH,and others).The reaction pathways are elucidated by analyzing the adsorption behavior,energy barriers,and intermediate coupling steps involved in the generation of each product.Particular emphasis is placed on the key intermediates,such as^(*)OCHO,^(*)COOH,^(*)CO,^(*)OCCOH,and^(*)CCO,which play crucial roles in determining the product selectivity.The effects of catalyst composition,morphology,and electronic structure on the adsorption and activation of these intermediates are also discussed.Moreover,advanced characterization techniques,including in-situ spectroscopy and isotopic labeling experiments,are highlighted for their contributions to unraveling the reaction mechanisms.The review aims to provide critical insights to reveal the activity-determining para meters and underlying CO_(2)RR mechanisms,which will guide the rational design of next-generation electrocatalysts for selective CO^(2)RR towards high-value products.展开更多
Designing catalyst to achieve ammonia synthesis at mild conditions is a meaningful challenge in catalysis community.Defective g-C_(3)N_(4)nanosheet supported single-cluster ruthenium and iron catalysts were investigat...Designing catalyst to achieve ammonia synthesis at mild conditions is a meaningful challenge in catalysis community.Defective g-C_(3)N_(4)nanosheet supported single-cluster ruthenium and iron catalysts were investigated for their ammonia synthesis performance.Based on density functional theory(DFT)calculations and microkinetic simulations,Ru_(3)single-cluster anchored on defective g-C3N4 nanosheet(Ru_(3)/Nv-g-C_(3)N_(4))has a turnover frequency(TOF)5.8 times higher than the Ru(0001)step surface at industrial reaction conditions of 673 K and 100 bar for ammonia synthesis.In other words,similar TOFs could be achieved on Ru_(3)/Nv-g-C_(3)N_(4)at much milder conditions(623 K,30 bar)than on Ru(0001)(673 K,100 bar).Our computations reveal the reaction proceeds parallelly on Ru_(3)/Nv-g-C_(3)N_(4)through both dissociative and alternative associative mechanisms at typical reaction conditions(600–700 K,10–100 bar);N–N bond cleavage of*N2 and*NNH from the two respective pathways controls the reaction collectively.With increasing temperatures or decreasing pressures,the dissociative mechanism gradually prevails and associative mechanism recedes.In comparison,Fe_(3)/Nv-g-C_(3)N_(4)catalyst shows a much lower catalytic activity than Ru3/Nv-g-C_(3)N_(4)by two orders of magnitude and the reaction occurs solely through the dissociative pathway.The finding provides a prospective candidate and deepens the mechanistic understanding for ammonia synthesis catalyzed by single-cluster catalysts(SCCs).展开更多
The electrochemical nitrogen reduction reaction(eNRR)holds significant promise as a sustainable alternative to the conventional large-scale Haber Bosch process,offering a carbon footprint-free approach for ammonia syn...The electrochemical nitrogen reduction reaction(eNRR)holds significant promise as a sustainable alternative to the conventional large-scale Haber Bosch process,offering a carbon footprint-free approach for ammonia synthesis.While the process is thermodynamically feasible at ambient temperature and pressure,challenges such as the competing hydrogen evolution reaction,low nitrogen solubility in electrolytes,and the activation of inert dinitrogen(N_(2))gas adversely affect the performance of ammonia production.These hurdles result in low Faradaic efficiency and low ammonia production rate,which pose obstacles to the commercialisation of the process.Researchers have been actively designing and proposing various electrocatalysts to address these issues,but challenges still need to be resolved.A key strategy in electrocatalyst design lies in understanding the underlying mechanisms that govern the success or failure of the electrocatalyst in driving the electrochemical reaction.Through mechanistic studies,we gain valuable insights into the factors affecting the reaction,enabling us to propose optimised designs to overcome the barriers.This review aims to provide a comprehensive understanding of the various mechanisms involved in eNRR on the electrocatalyst surface.It delves into the various mechanisms such as dissociative,associative,Mars-van Krevelen,lithium-mediated nitrogen reduction and surface hydrogenation mechanisms of nitrogen reduction.By unravelling the intricacies of eNRR mechanisms and exploring promising avenues,we can pave the way for more efficient and commercially viable ammonia synthesis through this sustainable electrochemical process by designing an efficient electrocatalyst.展开更多
The chain length and hydrocarbon type significantly affect the production of light olefins during the catalytic pyrolysis of naphtha.Herein,for a better catalyst design and operation parameters optimization,the reacti...The chain length and hydrocarbon type significantly affect the production of light olefins during the catalytic pyrolysis of naphtha.Herein,for a better catalyst design and operation parameters optimization,the reaction pathways and equilibrium yields for the catalytic pyrolysis of C_(5-8)n/iso/cyclo-paraffins were analyzed thermodynamically.The results revealed that the thermodynamically favorable reaction pathways for n/iso-paraffins and cyclo-paraffins were the protolytic and hydrogen transfer cracking pathways,respectively.However,the formation of light paraffin severely limits the maximum selectivity toward light olefins.The dehydrogenation cracking pathway of n/iso-paraffins and the protolytic cracking pathway of cyclo-paraffins demonstrated significantly improved selectivity for light olefins.The results are thus useful as a direction for future catalyst improvements,facilitating superior reaction pathways to enhance light olefins.In addition,the equilibrium yield of light olefins increased with increasing the chain length,and the introduction of cyclo-paraffin inhibits the formation of light olefins.High temperatures and low pressures favor the formation of ethylene,and moderate temperatures and low pressures favor the formation of propylene.n-Hexane and cyclohexane mixtures gave maximum ethylene and propylene yield of approximately 49.90%and 55.77%,respectively.This work provides theoretical guidance for the development of superior catalysts and the selection of proper operation parameters for the catalytic pyrolysis of C_(5-8)n/iso/cyclo-paraffins from a thermodynamic point of view.展开更多
Due to the instability of FeO at temperatures below 843 K,the fuidization reduction pathway of iron ore powder changes with the reduction temperature.Thus,the effect of temperature and reaction pathway interaction on ...Due to the instability of FeO at temperatures below 843 K,the fuidization reduction pathway of iron ore powder changes with the reduction temperature.Thus,the effect of temperature and reaction pathway interaction on the kinetics of fuidization reduction of iron ore powder under low-temperature conditions ranging from 783 to 903 K was investigated to describe the fluidization reduction rate of iron ore powder from three aspects:microstructure change,reaction limiting link,and apparent activation energy of the reaction,exploring their internal correlation.The experimental results revealed that in a temperature range of 783-813 K,the formation of a dense iron layer hindered the internal diffusion of reducing gas,resulting in relatively high gas diffusion resistance.In addition,due to the differences in limiting links and reaction pathways in the intermediate stage of reduction,the apparent activation energy of the reaction varied.The apparent activation energy of the reaction ranged from 23.36 to 89.13 kJ/mol at temperature ranging from 783 to 813 K,while it ranged from 14.30 to 68.34 kJ/mol at temperature ranging from 873 to 903 K.展开更多
Single-atom catalysts(SACs)offer a promising approach for maximizing noble metals utilization in catalytic processes.However,their performance in CO_(2)hydrogenation is often constrained by the nature of metal-support...Single-atom catalysts(SACs)offer a promising approach for maximizing noble metals utilization in catalytic processes.However,their performance in CO_(2)hydrogenation is often constrained by the nature of metal-support interactions.In this study,we synthesized TiO_(2)supported Pt SACs(Pt1/TiO_(2)),with Pt single atoms dispersed on rutile(Pt1/R)and anatase(Pt1/A)phases of TiO_(2)for the reverse water-gas shift(RWGS)reaction.While both catalysts maintained 100%CO selectivity over time,Pt1/A achieved a CO_(2)conversion of 7.5%,significantly outperforming Pt1/R(3.6%).In situ diffuse reflectance infrared Fourier-transform spectroscopy and X-ray photoelectron spectroscopy revealed distinct reaction pathways:the COOH pathway was dominant on Pt1/A,whereas the–OH+HCO pathway was more competitive on Pt1/R.Analysis of electron metal-support interactions and energy barrier calculations indicated that Pt1/A better stabilized metallic Pt species and facilitates more favorable reaction pathways with lower energy barriers.These findings provide valuable insights for the design of more efficient SAC systems in CO_(2)hydrogenation processes.展开更多
The mechanism of decomposition of calcium inosilicate(CaSiO_3) synthesized through chemical deposition method using analytical reagent NaSiO_3·9H_2O and CaCl_2 during the alkali fusion process using NaOH was inve...The mechanism of decomposition of calcium inosilicate(CaSiO_3) synthesized through chemical deposition method using analytical reagent NaSiO_3·9H_2O and CaCl_2 during the alkali fusion process using NaOH was investigated by Raman spectroscopy in situ,X-ray diffraction and Fourier transform infrared spectrometer(FTIR).The results show that the tetrahedral silica chains within CaSiO_3 are gradually disrupted and transformed into nesosilicate with the isolated SiO_4 tetrahedra at the beginning of the alkali fusion process.The three intermediates including Ca_2SiO_4,Na_2CaSiO_4 and Na_2SiO_3 appear simultaneously in the decomposition of CaSiO_3,while the final products are Ca(OH)_2 and Na_4SiO_4.It can be concluded that there exist two reaction pathways in the alkali fusion process of CaSiO_3:one is ion exchange,the other is in the main form of the framework structure change of silicate.The reaction pathway is led by silicate structure transformation in the alkali fusion process.展开更多
The function of microorganism and dissolution reaction pathway of carrollite in the bioleaching process were investigated. The results showed that both indirect and contact mechanisms influenced the leaching process. ...The function of microorganism and dissolution reaction pathway of carrollite in the bioleaching process were investigated. The results showed that both indirect and contact mechanisms influenced the leaching process. The dissolution of carrollite was significantly accelerated when bacteria were adsorbed on the mineral surface, indicating that the contact mechanism significantly affected the dissolution of carrollite. During bioleaching, the sequence of oxidation state of the sulfur moiety of carrollite was as follows： S？2→S0→S＋4→S＋6. Elemental sulfur precipitated on the mineral surface, indicating that the dissolution of carrollite occurred via the polysulfide pathway. The surface of carrollite was selectively corroded by bacteria, and oxidation pits with different sizes were observed at various sites. Elemental sulfur, sulfate and sulfite were present on the surface of carrollite during the leaching process, and may have formed a passivation layer on mineral surface.展开更多
Polymeric perylene diimide(PDI)has been evidenced as a good candidate for photocatalytic water oxidation,yet the origin of the photocatalytic oxygen evolution activity remains unclear and needs further exploration.Her...Polymeric perylene diimide(PDI)has been evidenced as a good candidate for photocatalytic water oxidation,yet the origin of the photocatalytic oxygen evolution activity remains unclear and needs further exploration.Herein,with crystal and atomic structures of the self-assembled PDI revealed from the X-ray diffraction pattern,the electronic structure is theoretically illustrated by the first-principles density functional theory calculations,suggesting the suitable band structure and the direct electronic transition for efficient photocatalytic oxygen evolution over PDI.It is confirmed that the carbonyl O atoms on the conjugation structure serve as the active sites for oxygen evolution reaction by the crystal orbital Hamiltonian group analysis.The calculations of reaction free energy changes indicate that the oxygen evolution reaction should follow the reaction pathway of H_(2)O→^(*)OH→^(*)O→^(*)OOH→^(*)O_(2)with an overpotential of 0.81 V.Through an in-depth theoretical computational analysis in the atomic and electronic structures,the origin of photocatalytic oxygen evolution activity for PDI is well illustrated,which would help the rational design and modification of polymeric photocatalysts for efficient oxygen evolution.展开更多
Density functional theory(DFT)is used to calculate the most stable structures of Zr_(n)(n=2-5)clusters as well as the adsorption energy values of Zr_(n)(n=2-5)clusters after adsorbing single water molecule.The results...Density functional theory(DFT)is used to calculate the most stable structures of Zr_(n)(n=2-5)clusters as well as the adsorption energy values of Zr_(n)(n=2-5)clusters after adsorbing single water molecule.The results reveal that there is a significant linear relationship between the adsorption energy values and the energy gaps of the Zr_(n)(n=2-5)clusters.Furthermore,the calculations of the reaction paths between Zr_(n)(n=2-5)and single water molecule show that water molecule can react with Zr_(n)(n=2-5)clusters to dissociate,producing hydrogen,and O atoms mix with the clusters to generate Zr_(n)O(n=2-5),all of which are exothermic reactions.According to the released energy,the Zr4 cluster is the most efficient in Zr_(n)(n=2-5)clusters reacting with single water molecule.The natural population analysis(NPA)and density of states(DOS)demonstrate the production of hydrogen and orbital properties in different energy ranges,respectively,jointly forecasting that Zr_(n)O(n=2-5)will probably continue to react with more water molecules.Our findings contribute to better understanding of Zr's chemical reactivity,which can conduce to the development of effective Zr-based catalysts and hydrogen-production methods.展开更多
In this study, we examined the key particles and chemical reactions that substantially influence plasma characteristics. In summarizing the chemical reaction model for the discharge process of N_(2)–O_(2)–H_(2)O(g)m...In this study, we examined the key particles and chemical reactions that substantially influence plasma characteristics. In summarizing the chemical reaction model for the discharge process of N_(2)–O_(2)–H_(2)O(g)mixed gases, 65 particle types and 673 chemical reactions were investigated. On this basis, a global model of atmospheric pressure humid air discharge plasma was developed, with a focus on the variation of charged particles densities and chemical reaction rates with time under the excitation of a 0–200 Td pulsed electric field. Particles with a density greater than 1% of the electron density were classified as key particles. For such particles, the top ranking generation or consumption reactions(i.e. where the sum of their rates was greater than 95% of the total rate of the generation or consumption reactions) were classified as key chemical reactions. On the basis of the key particles and reactions identified, a simplified global model was derived. A comparison of the global model with the simplified global model in terms of the model parameters, particle densities, reaction rates(with time), and calculation efficiencies demonstrated that both models can adequately identify the key particles and chemical reactions reflecting the chemical process of atmospheric pressure discharge plasma in humid air. Thus, by analyzing the key particles and chemical reaction pathways, the charge and substance transfer mechanism of atmospheric pressure pulse discharge plasma in humid air was revealed, and the mechanism underlying water vapor molecules’ influence on atmospheric pressure air discharge was elucidated.展开更多
Upgrading of abundant cellulosic biomass to isosorbide can reduce the dependence on limited fossil resources and provide a sustainable way to produce isosorbide,utilized for polymers,medicine and health care product s...Upgrading of abundant cellulosic biomass to isosorbide can reduce the dependence on limited fossil resources and provide a sustainable way to produce isosorbide,utilized for polymers,medicine and health care product synth-esis.This review comprehensively examines the key steps and catalytic systems involved in the conversion of cel-lulose to isosorbide.Initially,the reaction pathway from cellulose to isosorbide is elucidated,emphasizing three critical steps:cellulose hydrolysis,glucose hydrogenation,and the two-step dehydration of sorbitol to produce isosorbide.Additionally,the activation energy and acidic sites during cellulose hydrolysis,the impact of metal particle size and catalyst support on hydrogenation,and the effects of catalyst acidity,pore structure,and reaction conditions on sorbitol dehydration have been thoroughly examined.Finally,the progress made in cellulose con-version to isosorbide is summarized,current challenges are highlighted,and future development trends are pro-jected in this review.展开更多
Global interest in lithium-sulfur batteries as one of the most promising energy storage technologies has been sparked by their low sulfur cathode cost,high gravimetric,volumetric energy densities,abundant resources,an...Global interest in lithium-sulfur batteries as one of the most promising energy storage technologies has been sparked by their low sulfur cathode cost,high gravimetric,volumetric energy densities,abundant resources,and environmental friendliness.However,their practical application is significantly impeded by several serious issues that arise at the cathode-electrolyte interface,such as interface structure degradation including the uneven deposition of Li_(2)S,unstable cathode-electrolyte interphase(CEI)layer and intermediate polysulfide shuttle effect.Thus,an optimized cathode-electrolyte interface along with optimized electrodes is required for overall improvement.Herein,we comprehensively outline the challenges and corresponding strategies,including electrolyte optimization to create a dense CEI layer,regulating the Li_(2)S deposition pattern,and inhibiting the shuttle effect with regard to the solid-liquid-solid pathway,the transformation from solid-liquid-solid to solid-solid pathway,and solid-solid pathway at the cathode-electrolyte interface.In order to spur more perceptive research and hasten the widespread use of lithium-sulfur batteries,viewpoints on designing a stable interface with a deep comprehension are also put forth.展开更多
Piezocatalytic hydrogen peroxide(H_(2)O_(2))generation is a promising synthesis method that has received increasing attention;however,the reaction pathway requires further investigation.Here,Bi_(5)Ti_(3)FeO_(15)nanofi...Piezocatalytic hydrogen peroxide(H_(2)O_(2))generation is a promising synthesis method that has received increasing attention;however,the reaction pathway requires further investigation.Here,Bi_(5)Ti_(3)FeO_(15)nanofibers are used to generate H_(2)O_(2)by harvesting mechanical energy,and the reaction pathways are investigated.The H_(2)O_(2)yield over Bi_(5)Ti_(3)FeO_(15)nanofibers steadily increases from 331μmol g1 h1 in the first cycle to 746μmol g1 h1 in the tenth cycle in pure water without a sacrificial agent.Reliable reaction pathways are revealed by monitoring the pH value changes in the reaction solution during the H_(2)O_(2)generation process.In the H_(2)O_(2)generation process,the water oxidation reaction(WOR)provides a large amount of H+in the reaction solution,which promotes the oxygen reduction reaction(ORR)for H_(2)O_(2)generation.Therefore,an efficient synergistic effect between ORR and WOR achieves dual-pathway H_(2)O_(2)generation,contributing to the excellent piezocatalytic performance of Bi_(5)Ti_(3)FeO_(15)nanofibers.Furthermore,mechanistic studies indicate that the piezocatalytic H_(2)O_(2)generation follows the energy band theory.This work not only demonstrates Bi_(5)Ti_(3)FeO_(15)nanofibers as efficient piezocatalysts for H_(2)O_(2)generation but also provides a simple and effective approach to elucidate reaction pathways.This approach can be applied in photocatalytic,tribocatalytic,and electrocatalytic H_(2)O_(2)generation.展开更多
The development of highly active carbon material catalysts in catalytic wet air oxidation（CWAO）has attracted a great deal of attention. In this study different carbon material catalysts（multi-walled carbon nanotube...The development of highly active carbon material catalysts in catalytic wet air oxidation（CWAO）has attracted a great deal of attention. In this study different carbon material catalysts（multi-walled carbon nanotubes,carbon fibers and graphite） were developed to enhance the CWAO of phenol in aqueous solution. The functionalized carbon materials exhibited excellent catalytic activity in the CWAO of phenol. After 60 min reaction,the removal of phenol was nearly100% over the functionalized multi-walled carbon,while it was only 14% over the purified multi-walled carbon under the same reaction conditions. Carboxylic acid groups introduced on the surface of the functionalized carbon materials play an important role in the catalytic activity in CWAO. They can promote the production of free radicals,which act as strong oxidants in CWAO. Based on the analysis of the intermediates produced in the CWAO reactions,a new reaction pathway for the CWAO of phenol was proposed in this study. There are some differences between the proposed reaction pathway and that reported in the literature. First,maleic acid is transformed directly into malonic acid. Second,acetic acid is oxidized into an unknown intermediate,which is then oxidized into CO2 and H2O. Finally,formic acid and oxalic acid can mutually interconvert when conditions are favorable.展开更多
基金supported by the National Natural Science Foundation of China(52301259 and 22208019)the Research Fund Program for Young Scholars of Beijing Institute of Technology。
文摘Electrochemical carbon dioxide reduction reaction(CO_(2)RR)converts CO_(2) into valuable chemicals by consuming renewable electricity at mild conditions,making it a promising approach to achieving carbon neutrality.However,the reaction of CO_(2) with hydroxide ions to form carbonates leads to low carbon utilization and energy efficiency in near-neutral or alkaline CO_(2)RR.The high concentration of protons in acidic media can effectively mitigate carbonate formation and deposition,thereby significantly minimizing carbon loss and energy consumption.Unfortunately,hydrogen evolution reaction(HER)is more kinetically favorable than CO_(2)RR in acidic media.Herein,we comprehensively overview recent progress in acidic CO_(2)RR and propose two strategies derived from the competing reaction pathways of HER and CO_(2)RR:one focuses on regulating the H+mass transport,while the other aims to modulate the intrinsic kinetic activity of CO_(2)RR.The two strategies are designed to compete for the limited active sites on the catalyst surface,inhibit side reactions,and enhance the activity and selectivity of CO_(2)RR.The representative approaches include modulating the interface electric field,constructing a local alkaline environment,and regulating competing adsorption sites.Finally,we also review the technical challenges and future perspectives of acidic CO_(2)RR coupled with membrane electrode assemblies(MEAs).
基金supported by the National Key Research&Development Program of China(2021YFB3803200)the National Natural Science Foundation of China(22288102).
文摘Hexafluoropropylene oxide(HFPO)is a crucial fluorinated chemical mainly synthesized from hexafluoropropylene(HFP)through the oxidation of oxygen.However,the reaction network and kinetic characteristics are not fully understood yet,resulting in a lack of theoretical basis for synthesis process improvement.Here,the free radical reaction mechanism and complete reaction network involved in the noncatalytic oxidation of HFP to synthesize HFPO was explored by density functional theory.Transition state theory was employed to calculate the intrinsic reaction rate constants for elementary reactions.Based on theoretical reaction rate ratios,reaction pathways were selected,and a simplified reaction network was derived.It was found that byproducts were formed owing to the decomposition of HFPO and subsequent reactions with excessive oxygen while oxygen tended to participate more in the main reaction under oxygen-deficient conditions.The variations in reaction pathways occurring at different HFP/oxygen molar ratios was well elucidated by comparing with experimental data.This research establishes a robust theoretical foundation for optimizing and regulating the synthesis of HFPO.
基金support from the National Natural Science Foundation of China(22271306)the Shanghai Rising-Star Program(22QA1411200)+5 种基金the National Key Research and Development Program of China(2024YFA1510600,2022YFA1206200)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0610000)the Shanghai Institute of Organic Chemistry and the Shanghai Branch,Chinese Academy of Sciencesthe support from the Postdoctoral Fellowship Program(GZC20232861)of the China Postdoctoral Science Foundationthe Shanghai Post-doctoral Excellence Program(2024723)the support from the Postdoctoral Fellowship Program(GZC20232858)of the China Postdoctoral Science Foundation。
文摘Photosynthesis converts solar energy into chemical energy through highly coordinated photosynthetic reactions.Inspired by natural systems,artificial photosynthesis aims to develop an efficient,sustainable,and cost-effective pathway for solar-tochemical conversion.This review examines natural photosynthetic pathways,including retinal/rhodopsin-,bacteriochlorophyll-,and chlorophyll-based systems,highlighting their key components and mechanisms.Next,we outline reaction pathways in artificial photosynthetic systems constructed via heterogeneous,homogeneous,self-assembly,and semi-artificial strategies,focusing on water splitting,carbon fixation,and nitrogen fixation.Finally,we offer insights into future directions for artificial photosynthesis,emphasizing the importance of using self-assembly strategies and the potential of using primitive phototrophic microorganisms as models.
基金supported by the National Natural Science Foundation of China(22202128 and U24A20540)the Shaanxi Fundamental Science Research Project for Chemistry and Biology(23JHQ074)+1 种基金the Special Fund Project of Jiangsu Province for Scientific and Technological Innovation in Carbon Peaking and Carbon Neutrality(BK20220023)the Tian Ka Ping Scholar Program。
文摘Hydrogen peroxide(H_(2)O_(2))is a versatile oxidant widely used in pharmaceuticals,environmental protection,and chemical manufacturing.However,conventional H_(2)O_(2)production relies on energy-intensive processes and costly metal-based catalysts,raising economic and environmental concerns.As a sustainable alternative,photocatalytic H_(2)O_(2)synthesis harnesses solar energy,water,and oxygen under mild conditions.This review summarizes recent advancements in the development of metal-free organic semiconductors for photocatalytic H_(2)O_(2)generation.Notably,it delves into novel surface reaction mechanisms,including anthraquinone(AQ)intermediate,peroxy acid intermediate,bipyridine intermediate,and dual channel synergistic mechanisms for optimizing photocatalyst performance.This review also umderscores the critical role of advanced characterization techniques,including in-situ characterizations and computational simulations,in elucidating structure-property relationships and monitoring real-time catalytic processes.By presenting novel strategies for material modification and exploring potential device-level applications,the review aims to inspire further research and facilitate the industrial implementation of photocatalytic H_(2)O_(2)production,thereby advancing sustainable chemical manufacturing.
基金financially supported by the National Natural Science Foundation of China(Grants 22225901,21975237 and 51702312)the Fundamental Research Funds for the Central Universities(Grant WK2340000101)+5 种基金the USTC Research Funds of the Double First-Class Initiative(Grant YD2340002007 and YD9990002017)the Open Funds of the State Key Laboratory of Rare Earth Resource Utilization(Grant RERU2022007)the China Postdoctoral Science Foundation(Grants 2023M733371,2024M750006 and 2023T160617)Postdoctoral Fellowship Program(Grade C)of China Postdoctoral Science Foundation(GZC20230008)the Natural Science Foundation Youth Project of Anhui Province(2408085QB065)the Postdoctoral Research Funding Project of Anhui Province(2023B727)。
文摘The electrochemical reduction of carbon dioxide(CO_(2))into value-added chemicals and fuels has been extensively studied as a promising strategy for mitigating environmental issues and achieving sustainable energy conversion.Substantial efforts have been made to improve the understanding of CO_(2)reduction reaction(CO_(2)RR)mechanisms by computational and spectroscopic studies.An in-depth understanding of CO_(2)RR mechanism can provide the guidance and criteria for designing high-efficiency catalysts,and hence,steering CO_(2)RR to desired products.This review systematically discusses the formation mechanisms and reaction pathways of various CO_(2)RR products,including C_(1)products(CO,HCOOH,and CH_(4)),C_(2)products(C_(2)H_(4),C_(2)H_(5)OH,and CH_(3)COOH),and C_(3+)products(C_(3)H_(6),C_(3)H_(7)OH,and others).The reaction pathways are elucidated by analyzing the adsorption behavior,energy barriers,and intermediate coupling steps involved in the generation of each product.Particular emphasis is placed on the key intermediates,such as^(*)OCHO,^(*)COOH,^(*)CO,^(*)OCCOH,and^(*)CCO,which play crucial roles in determining the product selectivity.The effects of catalyst composition,morphology,and electronic structure on the adsorption and activation of these intermediates are also discussed.Moreover,advanced characterization techniques,including in-situ spectroscopy and isotopic labeling experiments,are highlighted for their contributions to unraveling the reaction mechanisms.The review aims to provide critical insights to reveal the activity-determining para meters and underlying CO_(2)RR mechanisms,which will guide the rational design of next-generation electrocatalysts for selective CO^(2)RR towards high-value products.
基金supported financially by the National Natural Science Foundation of China(Nos.91961125 and 22002085)supported by the“Fundamental Research Funds for the Central Universities”(No.2018JBZ107)+4 种基金Guangdong Basic and Applied Basic Research Foundation(No.2020A1515110832)“Key Program for International S&T Cooperation Projects of China”from the Ministry of Science and Technology of China(No.2018YFE0124600)Chemistry and Chemical Engineering Guangdong Laboratory(No.1932004)Science and Technology Project of Guangdong Province(No.2020B0101370001)the Project from China Petrochemical Corporation(No.S20L00151).
文摘Designing catalyst to achieve ammonia synthesis at mild conditions is a meaningful challenge in catalysis community.Defective g-C_(3)N_(4)nanosheet supported single-cluster ruthenium and iron catalysts were investigated for their ammonia synthesis performance.Based on density functional theory(DFT)calculations and microkinetic simulations,Ru_(3)single-cluster anchored on defective g-C3N4 nanosheet(Ru_(3)/Nv-g-C_(3)N_(4))has a turnover frequency(TOF)5.8 times higher than the Ru(0001)step surface at industrial reaction conditions of 673 K and 100 bar for ammonia synthesis.In other words,similar TOFs could be achieved on Ru_(3)/Nv-g-C_(3)N_(4)at much milder conditions(623 K,30 bar)than on Ru(0001)(673 K,100 bar).Our computations reveal the reaction proceeds parallelly on Ru_(3)/Nv-g-C_(3)N_(4)through both dissociative and alternative associative mechanisms at typical reaction conditions(600–700 K,10–100 bar);N–N bond cleavage of*N2 and*NNH from the two respective pathways controls the reaction collectively.With increasing temperatures or decreasing pressures,the dissociative mechanism gradually prevails and associative mechanism recedes.In comparison,Fe_(3)/Nv-g-C_(3)N_(4)catalyst shows a much lower catalytic activity than Ru3/Nv-g-C_(3)N_(4)by two orders of magnitude and the reaction occurs solely through the dissociative pathway.The finding provides a prospective candidate and deepens the mechanistic understanding for ammonia synthesis catalyzed by single-cluster catalysts(SCCs).
基金the Science and Engineering Research Board(SERB),Government of India for funding this work(Sanction No.EEQ/2021/001116)。
文摘The electrochemical nitrogen reduction reaction(eNRR)holds significant promise as a sustainable alternative to the conventional large-scale Haber Bosch process,offering a carbon footprint-free approach for ammonia synthesis.While the process is thermodynamically feasible at ambient temperature and pressure,challenges such as the competing hydrogen evolution reaction,low nitrogen solubility in electrolytes,and the activation of inert dinitrogen(N_(2))gas adversely affect the performance of ammonia production.These hurdles result in low Faradaic efficiency and low ammonia production rate,which pose obstacles to the commercialisation of the process.Researchers have been actively designing and proposing various electrocatalysts to address these issues,but challenges still need to be resolved.A key strategy in electrocatalyst design lies in understanding the underlying mechanisms that govern the success or failure of the electrocatalyst in driving the electrochemical reaction.Through mechanistic studies,we gain valuable insights into the factors affecting the reaction,enabling us to propose optimised designs to overcome the barriers.This review aims to provide a comprehensive understanding of the various mechanisms involved in eNRR on the electrocatalyst surface.It delves into the various mechanisms such as dissociative,associative,Mars-van Krevelen,lithium-mediated nitrogen reduction and surface hydrogenation mechanisms of nitrogen reduction.By unravelling the intricacies of eNRR mechanisms and exploring promising avenues,we can pave the way for more efficient and commercially viable ammonia synthesis through this sustainable electrochemical process by designing an efficient electrocatalyst.
基金The authors acknowledge the support from the National Natural Science Foundation of China(Grant No.22021004)the National Key Research and Development Program of China(Grant No.2020YFA0210900)。
文摘The chain length and hydrocarbon type significantly affect the production of light olefins during the catalytic pyrolysis of naphtha.Herein,for a better catalyst design and operation parameters optimization,the reaction pathways and equilibrium yields for the catalytic pyrolysis of C_(5-8)n/iso/cyclo-paraffins were analyzed thermodynamically.The results revealed that the thermodynamically favorable reaction pathways for n/iso-paraffins and cyclo-paraffins were the protolytic and hydrogen transfer cracking pathways,respectively.However,the formation of light paraffin severely limits the maximum selectivity toward light olefins.The dehydrogenation cracking pathway of n/iso-paraffins and the protolytic cracking pathway of cyclo-paraffins demonstrated significantly improved selectivity for light olefins.The results are thus useful as a direction for future catalyst improvements,facilitating superior reaction pathways to enhance light olefins.In addition,the equilibrium yield of light olefins increased with increasing the chain length,and the introduction of cyclo-paraffin inhibits the formation of light olefins.High temperatures and low pressures favor the formation of ethylene,and moderate temperatures and low pressures favor the formation of propylene.n-Hexane and cyclohexane mixtures gave maximum ethylene and propylene yield of approximately 49.90%and 55.77%,respectively.This work provides theoretical guidance for the development of superior catalysts and the selection of proper operation parameters for the catalytic pyrolysis of C_(5-8)n/iso/cyclo-paraffins from a thermodynamic point of view.
基金The authors gratefully acknowledge financial support by the National Natural Science Foundation of China-Xinjiang Joint Fund(U2003124)the National Natural Science Foundation of China(No.51974001)the University Outstanding Young Talents Funding Program(No.gxyq2019016).
文摘Due to the instability of FeO at temperatures below 843 K,the fuidization reduction pathway of iron ore powder changes with the reduction temperature.Thus,the effect of temperature and reaction pathway interaction on the kinetics of fuidization reduction of iron ore powder under low-temperature conditions ranging from 783 to 903 K was investigated to describe the fluidization reduction rate of iron ore powder from three aspects:microstructure change,reaction limiting link,and apparent activation energy of the reaction,exploring their internal correlation.The experimental results revealed that in a temperature range of 783-813 K,the formation of a dense iron layer hindered the internal diffusion of reducing gas,resulting in relatively high gas diffusion resistance.In addition,due to the differences in limiting links and reaction pathways in the intermediate stage of reduction,the apparent activation energy of the reaction varied.The apparent activation energy of the reaction ranged from 23.36 to 89.13 kJ/mol at temperature ranging from 783 to 813 K,while it ranged from 14.30 to 68.34 kJ/mol at temperature ranging from 873 to 903 K.
文摘Single-atom catalysts(SACs)offer a promising approach for maximizing noble metals utilization in catalytic processes.However,their performance in CO_(2)hydrogenation is often constrained by the nature of metal-support interactions.In this study,we synthesized TiO_(2)supported Pt SACs(Pt1/TiO_(2)),with Pt single atoms dispersed on rutile(Pt1/R)and anatase(Pt1/A)phases of TiO_(2)for the reverse water-gas shift(RWGS)reaction.While both catalysts maintained 100%CO selectivity over time,Pt1/A achieved a CO_(2)conversion of 7.5%,significantly outperforming Pt1/R(3.6%).In situ diffuse reflectance infrared Fourier-transform spectroscopy and X-ray photoelectron spectroscopy revealed distinct reaction pathways:the COOH pathway was dominant on Pt1/A,whereas the–OH+HCO pathway was more competitive on Pt1/R.Analysis of electron metal-support interactions and energy barrier calculations indicated that Pt1/A better stabilized metallic Pt species and facilitates more favorable reaction pathways with lower energy barriers.These findings provide valuable insights for the design of more efficient SAC systems in CO_(2)hydrogenation processes.
基金Project(20112120120003)supported by the Science and Technology Projects of Ministry of Education of ChinaProject(L2014120)supported by the Educational Commission of Liaoning Province,China
文摘The mechanism of decomposition of calcium inosilicate(CaSiO_3) synthesized through chemical deposition method using analytical reagent NaSiO_3·9H_2O and CaCl_2 during the alkali fusion process using NaOH was investigated by Raman spectroscopy in situ,X-ray diffraction and Fourier transform infrared spectrometer(FTIR).The results show that the tetrahedral silica chains within CaSiO_3 are gradually disrupted and transformed into nesosilicate with the isolated SiO_4 tetrahedra at the beginning of the alkali fusion process.The three intermediates including Ca_2SiO_4,Na_2CaSiO_4 and Na_2SiO_3 appear simultaneously in the decomposition of CaSiO_3,while the final products are Ca(OH)_2 and Na_4SiO_4.It can be concluded that there exist two reaction pathways in the alkali fusion process of CaSiO_3:one is ion exchange,the other is in the main form of the framework structure change of silicate.The reaction pathway is led by silicate structure transformation in the alkali fusion process.
基金Project(2012AA061502)supported by the National High-tech Research and Development Program of ChinaProjects(51374066,51304047)supported by the National Natural Science Foundation of ChinaProject(2012223002)supported by Industrial Research Projects in Liaoning Province,China
文摘The function of microorganism and dissolution reaction pathway of carrollite in the bioleaching process were investigated. The results showed that both indirect and contact mechanisms influenced the leaching process. The dissolution of carrollite was significantly accelerated when bacteria were adsorbed on the mineral surface, indicating that the contact mechanism significantly affected the dissolution of carrollite. During bioleaching, the sequence of oxidation state of the sulfur moiety of carrollite was as follows： S？2→S0→S＋4→S＋6. Elemental sulfur precipitated on the mineral surface, indicating that the dissolution of carrollite occurred via the polysulfide pathway. The surface of carrollite was selectively corroded by bacteria, and oxidation pits with different sizes were observed at various sites. Elemental sulfur, sulfate and sulfite were present on the surface of carrollite during the leaching process, and may have formed a passivation layer on mineral surface.
基金supported by National Natural Science Foundation of China(No.523B2070,No.52225606).
文摘Polymeric perylene diimide(PDI)has been evidenced as a good candidate for photocatalytic water oxidation,yet the origin of the photocatalytic oxygen evolution activity remains unclear and needs further exploration.Herein,with crystal and atomic structures of the self-assembled PDI revealed from the X-ray diffraction pattern,the electronic structure is theoretically illustrated by the first-principles density functional theory calculations,suggesting the suitable band structure and the direct electronic transition for efficient photocatalytic oxygen evolution over PDI.It is confirmed that the carbonyl O atoms on the conjugation structure serve as the active sites for oxygen evolution reaction by the crystal orbital Hamiltonian group analysis.The calculations of reaction free energy changes indicate that the oxygen evolution reaction should follow the reaction pathway of H_(2)O→^(*)OH→^(*)O→^(*)OOH→^(*)O_(2)with an overpotential of 0.81 V.Through an in-depth theoretical computational analysis in the atomic and electronic structures,the origin of photocatalytic oxygen evolution activity for PDI is well illustrated,which would help the rational design and modification of polymeric photocatalysts for efficient oxygen evolution.
基金Project supported by the Open Research Fund of Computational Physics Key Laboratory of Sichuan Province,Yibin University,China(Grant No.YBXYJSWL-ZD-2020-005)the Student’s Platform for Innovation and Entrepreneurship Training Program,China(Grant No.S202110616084)。
文摘Density functional theory(DFT)is used to calculate the most stable structures of Zr_(n)(n=2-5)clusters as well as the adsorption energy values of Zr_(n)(n=2-5)clusters after adsorbing single water molecule.The results reveal that there is a significant linear relationship between the adsorption energy values and the energy gaps of the Zr_(n)(n=2-5)clusters.Furthermore,the calculations of the reaction paths between Zr_(n)(n=2-5)and single water molecule show that water molecule can react with Zr_(n)(n=2-5)clusters to dissociate,producing hydrogen,and O atoms mix with the clusters to generate Zr_(n)O(n=2-5),all of which are exothermic reactions.According to the released energy,the Zr4 cluster is the most efficient in Zr_(n)(n=2-5)clusters reacting with single water molecule.The natural population analysis(NPA)and density of states(DOS)demonstrate the production of hydrogen and orbital properties in different energy ranges,respectively,jointly forecasting that Zr_(n)O(n=2-5)will probably continue to react with more water molecules.Our findings contribute to better understanding of Zr's chemical reactivity,which can conduce to the development of effective Zr-based catalysts and hydrogen-production methods.
基金supported by National Natural Science Foundation of China(No.51907145)。
文摘In this study, we examined the key particles and chemical reactions that substantially influence plasma characteristics. In summarizing the chemical reaction model for the discharge process of N_(2)–O_(2)–H_(2)O(g)mixed gases, 65 particle types and 673 chemical reactions were investigated. On this basis, a global model of atmospheric pressure humid air discharge plasma was developed, with a focus on the variation of charged particles densities and chemical reaction rates with time under the excitation of a 0–200 Td pulsed electric field. Particles with a density greater than 1% of the electron density were classified as key particles. For such particles, the top ranking generation or consumption reactions(i.e. where the sum of their rates was greater than 95% of the total rate of the generation or consumption reactions) were classified as key chemical reactions. On the basis of the key particles and reactions identified, a simplified global model was derived. A comparison of the global model with the simplified global model in terms of the model parameters, particle densities, reaction rates(with time), and calculation efficiencies demonstrated that both models can adequately identify the key particles and chemical reactions reflecting the chemical process of atmospheric pressure discharge plasma in humid air. Thus, by analyzing the key particles and chemical reaction pathways, the charge and substance transfer mechanism of atmospheric pressure pulse discharge plasma in humid air was revealed, and the mechanism underlying water vapor molecules’ influence on atmospheric pressure air discharge was elucidated.
文摘Upgrading of abundant cellulosic biomass to isosorbide can reduce the dependence on limited fossil resources and provide a sustainable way to produce isosorbide,utilized for polymers,medicine and health care product synth-esis.This review comprehensively examines the key steps and catalytic systems involved in the conversion of cel-lulose to isosorbide.Initially,the reaction pathway from cellulose to isosorbide is elucidated,emphasizing three critical steps:cellulose hydrolysis,glucose hydrogenation,and the two-step dehydration of sorbitol to produce isosorbide.Additionally,the activation energy and acidic sites during cellulose hydrolysis,the impact of metal particle size and catalyst support on hydrogenation,and the effects of catalyst acidity,pore structure,and reaction conditions on sorbitol dehydration have been thoroughly examined.Finally,the progress made in cellulose con-version to isosorbide is summarized,current challenges are highlighted,and future development trends are pro-jected in this review.
基金supported by the National Natural Science Foundation of China(Grant Nos.52102302,22409161 and 52472249)the Young Talent Support Plan of Xi’an Jiaotong University(Grant No.DQ6J011)+4 种基金the Natural Science Foundation of Shaanxi Province(2023-JC-QN-0115)the China Postdoctoral Science Foundation(2022M712499)Beilin District Science and Technology Plan(GX2328)the support from Young Elite Scientists Sponsorship Program by Chinese Association for Science and Technologythe“High-Level Talent Introduction Plan”of Shaanxi Province and Siyuan Scholar of Xi’an Jiaotong University。
文摘Global interest in lithium-sulfur batteries as one of the most promising energy storage technologies has been sparked by their low sulfur cathode cost,high gravimetric,volumetric energy densities,abundant resources,and environmental friendliness.However,their practical application is significantly impeded by several serious issues that arise at the cathode-electrolyte interface,such as interface structure degradation including the uneven deposition of Li_(2)S,unstable cathode-electrolyte interphase(CEI)layer and intermediate polysulfide shuttle effect.Thus,an optimized cathode-electrolyte interface along with optimized electrodes is required for overall improvement.Herein,we comprehensively outline the challenges and corresponding strategies,including electrolyte optimization to create a dense CEI layer,regulating the Li_(2)S deposition pattern,and inhibiting the shuttle effect with regard to the solid-liquid-solid pathway,the transformation from solid-liquid-solid to solid-solid pathway,and solid-solid pathway at the cathode-electrolyte interface.In order to spur more perceptive research and hasten the widespread use of lithium-sulfur batteries,viewpoints on designing a stable interface with a deep comprehension are also put forth.
文摘Piezocatalytic hydrogen peroxide(H_(2)O_(2))generation is a promising synthesis method that has received increasing attention;however,the reaction pathway requires further investigation.Here,Bi_(5)Ti_(3)FeO_(15)nanofibers are used to generate H_(2)O_(2)by harvesting mechanical energy,and the reaction pathways are investigated.The H_(2)O_(2)yield over Bi_(5)Ti_(3)FeO_(15)nanofibers steadily increases from 331μmol g1 h1 in the first cycle to 746μmol g1 h1 in the tenth cycle in pure water without a sacrificial agent.Reliable reaction pathways are revealed by monitoring the pH value changes in the reaction solution during the H_(2)O_(2)generation process.In the H_(2)O_(2)generation process,the water oxidation reaction(WOR)provides a large amount of H+in the reaction solution,which promotes the oxygen reduction reaction(ORR)for H_(2)O_(2)generation.Therefore,an efficient synergistic effect between ORR and WOR achieves dual-pathway H_(2)O_(2)generation,contributing to the excellent piezocatalytic performance of Bi_(5)Ti_(3)FeO_(15)nanofibers.Furthermore,mechanistic studies indicate that the piezocatalytic H_(2)O_(2)generation follows the energy band theory.This work not only demonstrates Bi_(5)Ti_(3)FeO_(15)nanofibers as efficient piezocatalysts for H_(2)O_(2)generation but also provides a simple and effective approach to elucidate reaction pathways.This approach can be applied in photocatalytic,tribocatalytic,and electrocatalytic H_(2)O_(2)generation.
基金supported by the National Natural Science Foundation of China (No.51078143)the Fundamental Research Funds for the Central Universities of China
文摘The development of highly active carbon material catalysts in catalytic wet air oxidation（CWAO）has attracted a great deal of attention. In this study different carbon material catalysts（multi-walled carbon nanotubes,carbon fibers and graphite） were developed to enhance the CWAO of phenol in aqueous solution. The functionalized carbon materials exhibited excellent catalytic activity in the CWAO of phenol. After 60 min reaction,the removal of phenol was nearly100% over the functionalized multi-walled carbon,while it was only 14% over the purified multi-walled carbon under the same reaction conditions. Carboxylic acid groups introduced on the surface of the functionalized carbon materials play an important role in the catalytic activity in CWAO. They can promote the production of free radicals,which act as strong oxidants in CWAO. Based on the analysis of the intermediates produced in the CWAO reactions,a new reaction pathway for the CWAO of phenol was proposed in this study. There are some differences between the proposed reaction pathway and that reported in the literature. First,maleic acid is transformed directly into malonic acid. Second,acetic acid is oxidized into an unknown intermediate,which is then oxidized into CO2 and H2O. Finally,formic acid and oxalic acid can mutually interconvert when conditions are favorable.
