Catalytic purification of sulphur-containing malodorous gases has attracted wide attention because of its advantages of high purification efficiency,low energy consumption and lack of secondary pollution.The selection...Catalytic purification of sulphur-containing malodorous gases has attracted wide attention because of its advantages of high purification efficiency,low energy consumption and lack of secondary pollution.The selection of efficient catalysts is the key to the problem,while the preparation and optimisation of catalysts depend on the analysis of experimental results and in-depth mechanistic analysis.By analysing the published literature,bibliometric analysis can identify existing research hotspots,the areas of interest and predict development trends,which can help to identify hot catalysts in the catalytic purification of sulphurcontaining odours and to investigate their catalytic purification mechanisms.Therefore,this paper uses bibliometric analysis,based on Web Of Science and CNKI databases,CiteSpace and VOS viewer software to collate and analyse the literature on the purification of sulphurcontaining odour pollutants,to identify the current research hotspots,to summarise the progress of research on the catalytic purification of different types of sulphur-containing odours,and to analyse their reaction mechanisms and kinetics.On this basis,the research progress of catalytic purification of different kinds of sulfur odour is summarized,and the reaction mechanism and dynamics are summarized.展开更多
Zeolite-loaded noble metal catalysts have demonstrated excellent performance in addressing cold-start automotive exhaust NOx emissions and catalytic oxidation of VOCs applications.Pd and Pt are the most commonly used ...Zeolite-loaded noble metal catalysts have demonstrated excellent performance in addressing cold-start automotive exhaust NOx emissions and catalytic oxidation of VOCs applications.Pd and Pt are the most commonly used active metals in PNA and VOC catalysts,respectively.However,despite the same metal/zeolite composition,the efficient active sites for PNA and VOC catalysts have been viewed as mainly Pd^(2+) and Pt^(0),respectively,both of which are different from each other.As a result,various methods need to be applied to dope Pd and Pt in zeolitic support respectively for different usages.No matter which type of metal species is needed,the common requirement for both PNA and VOC catalysts is that the metal species should be highly dispersed in zeolite support and stay stable.The purpose of this paper is to review the progress of synthetic means of zeolite-coated noble metals(Pd,Pt,etc.)as effective PNA or VOC catalysts.To give a better understanding of the relationship between efficient metal species and the introduced methods,the species that contributed to the NOx adsorption(PNA)and VOCs deep catalytic oxidation were first summarized and compared.Then,based on the above discussion,the detailed construction strategies for different active sites in PNA and VOC catalysts,respectively,were elaborated in terms of synthetic routes,precursor selection,and zeolite carrier requirements.It is hoped that this will contribute to a better understanding of noble metal adsorption/catalysis in zeolites and provide promising strategies for the design of adsorption/catalysts with high activity,selectivity and stability.展开更多
Ammonia selective catalytic reduction(NH_(3)-SCR)is the most widely used technology in thefield of industrialflue gas denitrification.However,the presence of heavy metals influe gas can seriously affect the performance of...Ammonia selective catalytic reduction(NH_(3)-SCR)is the most widely used technology in thefield of industrialflue gas denitrification.However,the presence of heavy metals influe gas can seriously affect the performance of SCR catalysts,leading to their deactivation or even failure.Therefore,it is of great significance to deeply study the poisoning mechanism of SCR catalysts under the action of heavy metals and how to enhance their resistance to poisoning.This article reviews the reaction mechanism of NH_(3)-SCR technology,compares the impact of heavy metals on the activity of different SCR catalysts,and then discusses in detail the poisoning mechanism of SCR catalysts by heavy metals,including pore blockage,reduction of specific surface area,and destruction of active centers caused by heavy metal deposition,all of which jointly lead to the physical or chemical poisoning of the catalyst.Meanwhile,the mechanism of action when multiple toxicants coexist was analyzed.To effectively address these challenges,the article further summarizes various methods to improve the catalyst's resistance to heavy metal poisoning,such as element doping,structural optimization,and carrier addition,which significantly enhance the heavy metal resistance of the catalyst.Finally,the article provides a prospective analysis of the challenges faced by NH_(3)-SCR catalysts in anti-heavy metal poisoning technology,emphasizing the necessity of in-depth research on the poisoning mechanism,exploration of the mechanism of synergistic action of multiple pollutants,development of comprehensive anti-poisoning strategies,and research on catalyst regeneration technology,in order to promote the development of efficient anti-heavy metal poisoning NH_(3)-SCR catalysts.展开更多
Hierarchical ZSM-11 microspheres with intercrystalline mesoporous properties and rod-like crystals intergrowth morphology have been synthesized using a spot of tetrabutylammonium as a single template.XRD,FTIR,SEM,TEM ...Hierarchical ZSM-11 microspheres with intercrystalline mesoporous properties and rod-like crystals intergrowth morphology have been synthesized using a spot of tetrabutylammonium as a single template.XRD,FTIR,SEM,TEM and N2 adsorption analysis revealed that each individual particle was composed of nanosized rod crystals inserting each other and the intercrystalline voids existing among rods gave a significant mesopore size distribution.Steam treatment result demonstrated the excellent hydrothermal stability of samples.Various crystallization modes including constant temperature crystallization (one-stage crystallization) and two-stage temperature-varying crystallization with different 1st stage durations were investigated.The results suggested that the crystallization modes were mainly responsible for the adjustable particle size and textural properties of samples while the small amount of tetrabutylammonium bromide was mainly used to direct the formation of both ZSM-11 framework and its intergrowth morphology.Furthermore,the performance of optimal ZSM-11 as an active component for the catalytic pyrolysis of heavy oil was also investigated.Compared with the commercial pyrolysis catalyst,the hierarchical ZSM-11 catalyst exhibited a high selectivity to desired products(LPG+gasoline+diesel),as well as a much lower dry gas and coke yield,plus a high selectivity and yield of light olefins(C=3 C=4)and very poor selectivity to benzene.Therefore,fully open micropore-mesopore connectivity would make such hierarchically porous ZSM-11 zeolites very attractive for applications in clean petrochemical catalysis field.展开更多
As the main contributor of the formation of particulate matter as well as ozone, volatile organic compounds(VOCs) greatly affect human health and the environmental quality. Catalytic combustion/oxidation has been view...As the main contributor of the formation of particulate matter as well as ozone, volatile organic compounds(VOCs) greatly affect human health and the environmental quality. Catalytic combustion/oxidation has been viewed as an efficient, economically feasible and environmentally friendly way for the elimination of VOCs. Supported metal catalyst is the preferred type of catalysts applied for VOCs catalytic combustion because of the synergy between active components and support as well as its flexibility in the composition. The presence of support not only plays the role of keeping the catalyst with good stability and mechanical strength, but also provides a large specific surface for the good dispersion of active components, which could effectively improve the performance of catalyst as well as decrease the usage of active components, especially the noble metal amount. Mesoporous molecular sieves, owing to their large surface area, unique porous structures, large pore size as well as uniform pore-size distribution, were viewed as superior support for dispersing active components. This review focuses on the recent development of mesoporous molecular sieve supported metal catalysts and their application in catalytic oxidation of VOCs. The effect of active component types, support structure, preparation method, precursors, etc. on the valence state, dispersion as well as the loading of active species were also discussed and summarized. Moreover, the corresponding conversion route of VOCs was also addressed.This review aims to provide some enlightment for designing the supported metal catalysts with superior activity and stability for VOCs removal.展开更多
Cu-Co multiple-oxides modified on HNO_3-pretreated activated coke(AC_(N))were optimized for the simultaneous removal of gaseous CO and elemental mercury(Hg^(0))at low temperature(<200℃).It was found that 2%CuOx-10...Cu-Co multiple-oxides modified on HNO_3-pretreated activated coke(AC_(N))were optimized for the simultaneous removal of gaseous CO and elemental mercury(Hg^(0))at low temperature(<200℃).It was found that 2%CuOx-10%CoOx/AC_(N)catalyst calcined at 400℃resulted in the coexistence of complex oxides including CuO,Cu_2 O,Co_(3)O_(4,Co_(2)O_(3)and CoO phases,which might be good for the simultaneous catalytic oxidation of CO by Co-species and removal of Hg^(0)by Cu-species,benefiting from the synergistic catalysis during the electrointeraction between Go and Cu cations(CoO■Co_(3)O_(4)and Cu_(2)O■CuO).The catalysis removal of CO oxidation was obviously depended on the reaction temperature obtaining94.7%at 200℃,while no obvious promoting effect on the Hg^(0)removal(68.3%-78.7%).These materials were very substitute for the removal of CO and Hg^(0)from the flue gas with the conditions of 8-20 vol.%O_(2)and flue-gas temperature below 200℃.The removal of Hg^(0)followed the combination processes of adsorption and catalytic oxidation reaction via LangmuirHinshelwood mechanism,while the catalysis of CO abided by the Mars-van Krevelen mechanism with lattice oxygen species.展开更多
Mn-Si-MEL zeolite was developed as a bi-functional adsorption-catalytic oxidation material for volatile organic compounds(VOCs)elimination due to its good hydrophobicity&good organophileproperty brought by the sub...Mn-Si-MEL zeolite was developed as a bi-functional adsorption-catalytic oxidation material for volatile organic compounds(VOCs)elimination due to its good hydrophobicity&good organophileproperty brought by the substitution of Mn for Al in zeolite and the superior catalytic oxidation property endowed by the existence of Mn species.Various Mn-Si-MEL samples were obtained by introducing Mn to MEL crystallization system via different ways.It was found the incorporated Mn ways have a significant effect on the behavior of Mn being involved in the crystallization of MEL and finally influenced the distribution of Mn in zeolite as well the physicochemical properties of product zeolite.The seeding method(MnS2(Seed))is favorable for the good incorporation and uniform distribution of Mn in zeolite while both recrystallization method(Mn-S2(RC))and direct synthesis method(Mn-S2(DH))are favorable for obtaining more reducible Mn species and surface adsorbed oxygen species.The Mn amount incorporated into zeolite follows Mn-S2(RC)(1.96 wt%)>Mn-S2(Seed)(1.07 wt%)≈Mn-S2(DH)(0.97 wt%),the adsorption capacity of various samples follows Mn-S2(Seed)(83.3μmol/g)≈Mn-S2(RC)(82.1μmol/g)>Mn-S2(DH)(76.1μmol/g),while the catalytic oxidation ability of three samples follows Mn-S2(RC)≈Mn-S2(DH)>Mn-S2(Seed).Furthermore,Mn-S2(RC)which exhibits both superior adsorption capacity and catalytic oxidation ability shows good hydrophobicity and superior recyclability,demonstrating its great potential to be applied in the VOCs elimination by an enrichment-degradation route.展开更多
Ammonia(NH3)serves as a critical component in the fertilizer industry and fume gas denitrification.However,the conventional NH3production process,namely the Haber-Bosch process,leads to considerable energy consumption...Ammonia(NH3)serves as a critical component in the fertilizer industry and fume gas denitrification.However,the conventional NH3production process,namely the Haber-Bosch process,leads to considerable energy consumption and waste gas emissions.To address this,electrocatalytic nitric oxide reduction reaction(NORR)has emerged as a promising strategy to bridge NH3consumption to NH3production,harnessing renewable electricity for a sustainable future.Copper(Cu)stands out as a prominent electrocatalyst for NO reduction,given its exceptional NH3yield and selectivity.However,a crucial aspect that remains insufficiently explored is the effects of morphology and valence states of Cu on the NORR performance.In this investigation,we synthesized CuO nanowires(CuO-NF)and Cu nanocubes(Cu-NF)as cathodes through an in situ growth method.Remarkably,CuO-NF exhibited an impressive NH3yield of 0.50±0.02 mg cm^(-2)h^(-1)at-0.6 V vs.reversible hydrogen electrode(RHE)with faradaic efficiency of29,68%±1,35%,surpassing that of Cu-NF(0.17±0.01 mg cm^(-2)h^(-1),16.18%±1.40%).Throughout the electroreduction process,secondary cubes were generated on the CuO-NF surface,preserving their nanosheet cluster morphology,sustained by an abundant supply of subsurface oxygen(s-O)even after an extended duration of 10 h,until s-O depletion ensued.Conversely,Cu-NF exhibited inadequate s-O content,leading to rapid crystal collapse within the same timeframe.The distinctive current-potential relationship,akin to a volcano-type curve,was attributed to distinct NO hydrogenation mechanisms.Further Tafel analysis revealed the exchange current density(i0)and standard heterogeneous rate constant(k0)for CuO-NF,yielding 3.44×10^(-6)A cm^(-2)and 3.77×10^(-6)cm^(-2)s^(-1)when NORR was driven by overpotentials.These findings revealed the potential of CuO-NF for NO reduction and provided insights into the intricate interplay between crystal morphology,valence states,and electrochemical performance.展开更多
Energy-saving and efficient monolithic catalysts are hotspots of catalytic purification of industrial gaseous pollutants.Here,we have developed an electrothermal catalytic mode,in which the ignition temperature requir...Energy-saving and efficient monolithic catalysts are hotspots of catalytic purification of industrial gaseous pollutants.Here,we have developed an electrothermal catalytic mode,in which the ignition temperature required for the reaction is provided by Joule heat generated when the current flows through the catalyst.In this paper,Mn/NiAl/NF,Mn/NiFe/NF and Mn/NF metal-based monolithic catalysts were prepared using nickel foam (NF) as the carrier for thermal and electrothermal catalysis of n-heptane.The results indicated that Mn-based monolithic catalysts exhibit high activity in thermal and electrothermal catalysis.Mn/NiFe/NF achieve conversion of n-heptane more than 99%in electrothermal catalysis under a direct-current (DC) power of 6 W,and energy-saving is 54% compared with thermal catalysis.In addition,the results indicated that the introduction of NiAl (or NiFe) greatly enhanced the catalytic activity of Mn/NF,which attributed to the higher specific surface area,Mn3+/Mn4+,Ni3+/Ni^(2+),adsorbed oxygen species (Oads)/lattice oxygen species (Olatt),redox performance of the catalyst.Electrothermal catalytic activity was significantly higher than thermal catalytic activity before complete conversion,which may be related to electronic effects.Besides,Mn/NiFe/NF has good cyclic and long-term stability in electrothermal catalysis.This paper provided a theoretical basis for applying electrothermal catalysis in the field of VOCs elimination.展开更多
基金supported by the National Natural Science Foundation of China(Nos.21677010 and 51808037)the National Key R&D Program of China(No.2021YFB3500702)the Special fund of Beijing Key Laboratory of Indoor Air Quality Evaluation and Control(No.BZ0344KF21-04).
文摘Catalytic purification of sulphur-containing malodorous gases has attracted wide attention because of its advantages of high purification efficiency,low energy consumption and lack of secondary pollution.The selection of efficient catalysts is the key to the problem,while the preparation and optimisation of catalysts depend on the analysis of experimental results and in-depth mechanistic analysis.By analysing the published literature,bibliometric analysis can identify existing research hotspots,the areas of interest and predict development trends,which can help to identify hot catalysts in the catalytic purification of sulphurcontaining odours and to investigate their catalytic purification mechanisms.Therefore,this paper uses bibliometric analysis,based on Web Of Science and CNKI databases,CiteSpace and VOS viewer software to collate and analyse the literature on the purification of sulphurcontaining odour pollutants,to identify the current research hotspots,to summarise the progress of research on the catalytic purification of different types of sulphur-containing odours,and to analyse their reaction mechanisms and kinetics.On this basis,the research progress of catalytic purification of different kinds of sulfur odour is summarized,and the reaction mechanism and dynamics are summarized.
基金supported by Zhongtian Iron and Steel-University of Science and Technology Beijing Youth Science and Technology Innovation Fund(No.FZTNTC2024050005)National Engineering Laboratory for Mobile Source Emission Control Technology,China(No.NELMS2020A07)The Fundamental Research Funds for the Central Universities,China(No.FRF-AT-20-12)。
文摘Zeolite-loaded noble metal catalysts have demonstrated excellent performance in addressing cold-start automotive exhaust NOx emissions and catalytic oxidation of VOCs applications.Pd and Pt are the most commonly used active metals in PNA and VOC catalysts,respectively.However,despite the same metal/zeolite composition,the efficient active sites for PNA and VOC catalysts have been viewed as mainly Pd^(2+) and Pt^(0),respectively,both of which are different from each other.As a result,various methods need to be applied to dope Pd and Pt in zeolitic support respectively for different usages.No matter which type of metal species is needed,the common requirement for both PNA and VOC catalysts is that the metal species should be highly dispersed in zeolite support and stay stable.The purpose of this paper is to review the progress of synthetic means of zeolite-coated noble metals(Pd,Pt,etc.)as effective PNA or VOC catalysts.To give a better understanding of the relationship between efficient metal species and the introduced methods,the species that contributed to the NOx adsorption(PNA)and VOCs deep catalytic oxidation were first summarized and compared.Then,based on the above discussion,the detailed construction strategies for different active sites in PNA and VOC catalysts,respectively,were elaborated in terms of synthetic routes,precursor selection,and zeolite carrier requirements.It is hoped that this will contribute to a better understanding of noble metal adsorption/catalysis in zeolites and provide promising strategies for the design of adsorption/catalysts with high activity,selectivity and stability.
基金supported by National Natural Science Foundation of China(U20A20130)Fundamental Research Funds for the Central Universities(FRF-EYIT-23-07).
文摘Ammonia selective catalytic reduction(NH_(3)-SCR)is the most widely used technology in thefield of industrialflue gas denitrification.However,the presence of heavy metals influe gas can seriously affect the performance of SCR catalysts,leading to their deactivation or even failure.Therefore,it is of great significance to deeply study the poisoning mechanism of SCR catalysts under the action of heavy metals and how to enhance their resistance to poisoning.This article reviews the reaction mechanism of NH_(3)-SCR technology,compares the impact of heavy metals on the activity of different SCR catalysts,and then discusses in detail the poisoning mechanism of SCR catalysts by heavy metals,including pore blockage,reduction of specific surface area,and destruction of active centers caused by heavy metal deposition,all of which jointly lead to the physical or chemical poisoning of the catalyst.Meanwhile,the mechanism of action when multiple toxicants coexist was analyzed.To effectively address these challenges,the article further summarizes various methods to improve the catalyst's resistance to heavy metal poisoning,such as element doping,structural optimization,and carrier addition,which significantly enhance the heavy metal resistance of the catalyst.Finally,the article provides a prospective analysis of the challenges faced by NH_(3)-SCR catalysts in anti-heavy metal poisoning technology,emphasizing the necessity of in-depth research on the poisoning mechanism,exploration of the mechanism of synergistic action of multiple pollutants,development of comprehensive anti-poisoning strategies,and research on catalyst regeneration technology,in order to promote the development of efficient anti-heavy metal poisoning NH_(3)-SCR catalysts.
基金supported by the National Program on Key Basic Research Project(973 Program)(Grant No.2012CB215000)the financial support from Fundamental Research Funds for the Central Universities
文摘Hierarchical ZSM-11 microspheres with intercrystalline mesoporous properties and rod-like crystals intergrowth morphology have been synthesized using a spot of tetrabutylammonium as a single template.XRD,FTIR,SEM,TEM and N2 adsorption analysis revealed that each individual particle was composed of nanosized rod crystals inserting each other and the intercrystalline voids existing among rods gave a significant mesopore size distribution.Steam treatment result demonstrated the excellent hydrothermal stability of samples.Various crystallization modes including constant temperature crystallization (one-stage crystallization) and two-stage temperature-varying crystallization with different 1st stage durations were investigated.The results suggested that the crystallization modes were mainly responsible for the adjustable particle size and textural properties of samples while the small amount of tetrabutylammonium bromide was mainly used to direct the formation of both ZSM-11 framework and its intergrowth morphology.Furthermore,the performance of optimal ZSM-11 as an active component for the catalytic pyrolysis of heavy oil was also investigated.Compared with the commercial pyrolysis catalyst,the hierarchical ZSM-11 catalyst exhibited a high selectivity to desired products(LPG+gasoline+diesel),as well as a much lower dry gas and coke yield,plus a high selectivity and yield of light olefins(C=3 C=4)and very poor selectivity to benzene.Therefore,fully open micropore-mesopore connectivity would make such hierarchically porous ZSM-11 zeolites very attractive for applications in clean petrochemical catalysis field.
基金supported by the Open Research Fund Program of State Environmental Protection Key Laboratory of Food Chain Pollution Control (No. FC_(2)021YB05)the Opening Fund of State Key Laboratory of Heavy Oil Processing (No. SKLOP202002001)+1 种基金Fundamental Research Funds for the Central Universities (No. FRF-IDRY-20-004)National Natural Science Foundation of China (No. U20A20130)。
文摘As the main contributor of the formation of particulate matter as well as ozone, volatile organic compounds(VOCs) greatly affect human health and the environmental quality. Catalytic combustion/oxidation has been viewed as an efficient, economically feasible and environmentally friendly way for the elimination of VOCs. Supported metal catalyst is the preferred type of catalysts applied for VOCs catalytic combustion because of the synergy between active components and support as well as its flexibility in the composition. The presence of support not only plays the role of keeping the catalyst with good stability and mechanical strength, but also provides a large specific surface for the good dispersion of active components, which could effectively improve the performance of catalyst as well as decrease the usage of active components, especially the noble metal amount. Mesoporous molecular sieves, owing to their large surface area, unique porous structures, large pore size as well as uniform pore-size distribution, were viewed as superior support for dispersing active components. This review focuses on the recent development of mesoporous molecular sieve supported metal catalysts and their application in catalytic oxidation of VOCs. The effect of active component types, support structure, preparation method, precursors, etc. on the valence state, dispersion as well as the loading of active species were also discussed and summarized. Moreover, the corresponding conversion route of VOCs was also addressed.This review aims to provide some enlightment for designing the supported metal catalysts with superior activity and stability for VOCs removal.
基金financially supported by the National Key R&D Program of China(No.2017YFC0210303)the National Natural Science Foundation of China(Nos.21806009,21677010)+1 种基金the China Postdoctoral Science Foundation(No.2018M631344)。
文摘Cu-Co multiple-oxides modified on HNO_3-pretreated activated coke(AC_(N))were optimized for the simultaneous removal of gaseous CO and elemental mercury(Hg^(0))at low temperature(<200℃).It was found that 2%CuOx-10%CoOx/AC_(N)catalyst calcined at 400℃resulted in the coexistence of complex oxides including CuO,Cu_2 O,Co_(3)O_(4,Co_(2)O_(3)and CoO phases,which might be good for the simultaneous catalytic oxidation of CO by Co-species and removal of Hg^(0)by Cu-species,benefiting from the synergistic catalysis during the electrointeraction between Go and Cu cations(CoO■Co_(3)O_(4)and Cu_(2)O■CuO).The catalysis removal of CO oxidation was obviously depended on the reaction temperature obtaining94.7%at 200℃,while no obvious promoting effect on the Hg^(0)removal(68.3%-78.7%).These materials were very substitute for the removal of CO and Hg^(0)from the flue gas with the conditions of 8-20 vol.%O_(2)and flue-gas temperature below 200℃.The removal of Hg^(0)followed the combination processes of adsorption and catalytic oxidation reaction via LangmuirHinshelwood mechanism,while the catalysis of CO abided by the Mars-van Krevelen mechanism with lattice oxygen species.
基金the finance supported by the Opening Fund of State Key Laboratory of Heavy Oil Processing(No.SKLOP202002001)the Program for Fundamental Research Funds for the Central Universities(No.FRF-AT-20-12)National Natural Science Foundation of China(No.U20A20130).
文摘Mn-Si-MEL zeolite was developed as a bi-functional adsorption-catalytic oxidation material for volatile organic compounds(VOCs)elimination due to its good hydrophobicity&good organophileproperty brought by the substitution of Mn for Al in zeolite and the superior catalytic oxidation property endowed by the existence of Mn species.Various Mn-Si-MEL samples were obtained by introducing Mn to MEL crystallization system via different ways.It was found the incorporated Mn ways have a significant effect on the behavior of Mn being involved in the crystallization of MEL and finally influenced the distribution of Mn in zeolite as well the physicochemical properties of product zeolite.The seeding method(MnS2(Seed))is favorable for the good incorporation and uniform distribution of Mn in zeolite while both recrystallization method(Mn-S2(RC))and direct synthesis method(Mn-S2(DH))are favorable for obtaining more reducible Mn species and surface adsorbed oxygen species.The Mn amount incorporated into zeolite follows Mn-S2(RC)(1.96 wt%)>Mn-S2(Seed)(1.07 wt%)≈Mn-S2(DH)(0.97 wt%),the adsorption capacity of various samples follows Mn-S2(Seed)(83.3μmol/g)≈Mn-S2(RC)(82.1μmol/g)>Mn-S2(DH)(76.1μmol/g),while the catalytic oxidation ability of three samples follows Mn-S2(RC)≈Mn-S2(DH)>Mn-S2(Seed).Furthermore,Mn-S2(RC)which exhibits both superior adsorption capacity and catalytic oxidation ability shows good hydrophobicity and superior recyclability,demonstrating its great potential to be applied in the VOCs elimination by an enrichment-degradation route.
基金supported by the Fundamental Research Funds for the Central Universities(FRF-EYIT-23-07)。
文摘Ammonia(NH3)serves as a critical component in the fertilizer industry and fume gas denitrification.However,the conventional NH3production process,namely the Haber-Bosch process,leads to considerable energy consumption and waste gas emissions.To address this,electrocatalytic nitric oxide reduction reaction(NORR)has emerged as a promising strategy to bridge NH3consumption to NH3production,harnessing renewable electricity for a sustainable future.Copper(Cu)stands out as a prominent electrocatalyst for NO reduction,given its exceptional NH3yield and selectivity.However,a crucial aspect that remains insufficiently explored is the effects of morphology and valence states of Cu on the NORR performance.In this investigation,we synthesized CuO nanowires(CuO-NF)and Cu nanocubes(Cu-NF)as cathodes through an in situ growth method.Remarkably,CuO-NF exhibited an impressive NH3yield of 0.50±0.02 mg cm^(-2)h^(-1)at-0.6 V vs.reversible hydrogen electrode(RHE)with faradaic efficiency of29,68%±1,35%,surpassing that of Cu-NF(0.17±0.01 mg cm^(-2)h^(-1),16.18%±1.40%).Throughout the electroreduction process,secondary cubes were generated on the CuO-NF surface,preserving their nanosheet cluster morphology,sustained by an abundant supply of subsurface oxygen(s-O)even after an extended duration of 10 h,until s-O depletion ensued.Conversely,Cu-NF exhibited inadequate s-O content,leading to rapid crystal collapse within the same timeframe.The distinctive current-potential relationship,akin to a volcano-type curve,was attributed to distinct NO hydrogenation mechanisms.Further Tafel analysis revealed the exchange current density(i0)and standard heterogeneous rate constant(k0)for CuO-NF,yielding 3.44×10^(-6)A cm^(-2)and 3.77×10^(-6)cm^(-2)s^(-1)when NORR was driven by overpotentials.These findings revealed the potential of CuO-NF for NO reduction and provided insights into the intricate interplay between crystal morphology,valence states,and electrochemical performance.
基金financially supported by National Natural Science Foundation of China (Nos. 51808037 and 21876010)Fundamental Research Funds for the Central Universities, China (No. FRF-IDRY-20–018)+1 种基金China Postdoctoral Science Foundation (No. 2020M680903)Natural Science Foundation of Guangdong Province, China (No. 2020A1515011197)。
文摘Energy-saving and efficient monolithic catalysts are hotspots of catalytic purification of industrial gaseous pollutants.Here,we have developed an electrothermal catalytic mode,in which the ignition temperature required for the reaction is provided by Joule heat generated when the current flows through the catalyst.In this paper,Mn/NiAl/NF,Mn/NiFe/NF and Mn/NF metal-based monolithic catalysts were prepared using nickel foam (NF) as the carrier for thermal and electrothermal catalysis of n-heptane.The results indicated that Mn-based monolithic catalysts exhibit high activity in thermal and electrothermal catalysis.Mn/NiFe/NF achieve conversion of n-heptane more than 99%in electrothermal catalysis under a direct-current (DC) power of 6 W,and energy-saving is 54% compared with thermal catalysis.In addition,the results indicated that the introduction of NiAl (or NiFe) greatly enhanced the catalytic activity of Mn/NF,which attributed to the higher specific surface area,Mn3+/Mn4+,Ni3+/Ni^(2+),adsorbed oxygen species (Oads)/lattice oxygen species (Olatt),redox performance of the catalyst.Electrothermal catalytic activity was significantly higher than thermal catalytic activity before complete conversion,which may be related to electronic effects.Besides,Mn/NiFe/NF has good cyclic and long-term stability in electrothermal catalysis.This paper provided a theoretical basis for applying electrothermal catalysis in the field of VOCs elimination.
