The mesoporous hydroxyapatite (HA) was synthesized by hydrothermal method utilizing cationic surfactant cetyltrimethylammonium bromide (CTAB) as template. The crystalline phase, morphology and porous structure wer...The mesoporous hydroxyapatite (HA) was synthesized by hydrothermal method utilizing cationic surfactant cetyltrimethylammonium bromide (CTAB) as template. The crystalline phase, morphology and porous structure were characterized respectively by different detecting techniques. The results reveal that the particles are highly crystalline hydroxyapatite phase. The surfactant has little influence on the morphology of the crystals, but affects the porous structure obviously. The sample without CTAB has a low surface area not exceeding 33 m^2/g, and no distinct pores can be observed by TEM. While the samples obtained with the surfactant get better parameters. Numerous open-ended pores centered at 2-7 nm spread unequally on the surface of the hydroxyapatite nanorods. The N2 adsorption-desorption experiments show type IV isotherms with distinct hysteresis loops, illustrating the presence of mesoporous structure. When the mole ratio of CTAB to HA is 1:2, the sample has the largest surface area of 97.1 m^2/g and pore volume of 0.466 cm^3/g.展开更多
Lithium-sulfur batteries(LSBs)have drawn significant attention owing to their high theoretical discharge capacity and energy density.However,the dissolution of long-chain polysulfides into the electrolyte during the c...Lithium-sulfur batteries(LSBs)have drawn significant attention owing to their high theoretical discharge capacity and energy density.However,the dissolution of long-chain polysulfides into the electrolyte during the charge and discharge process(“shuttle effect”)results in fast capacity fading and inferior electrochemical performance.In this study,Mn_(2)O_(3)with an ordered mesoporous structure(OM-Mn_(2)O_(3))was designed as a cathode host for LSBs via KIT-6 hard templating,to effectively inhibit the polysulfide shuttle effect.OM-Mn_(2)O_(3)offers numerous pores to confine sulfur and tightly anchor the dissolved polysulfides through the combined effects of strong polar-polar interactions,polysulfides,and sulfur chain catenation.The OM-Mn_(2)O_(3)/S composite electrode delivered a discharge capacity of 561 mAh g^(-1) after 250 cycles at 0.5 C owing to the excellent performance of OM-Mn_(2)O_(3).Furthermore,it retained a discharge capacity of 628mA h g^(-1) even at a rate of 2 C,which was significantly higher than that of a pristine sulfur electrode(206mA h g^(-1)).These findings provide a prospective strategy for designing cathode materials for high-performance LSBs.展开更多
Developing cost-effective,robust and stable non-precious metal catalysts for oxygen reduction reaction(ORR) is of paramount importance for electrochemical energy conversion devices such as fuel cells and metal-air bat...Developing cost-effective,robust and stable non-precious metal catalysts for oxygen reduction reaction(ORR) is of paramount importance for electrochemical energy conversion devices such as fuel cells and metal-air batteries.Although Fe-N-C single atom catalysts(SACs) have been hailed as the most promising candidate due to the optimal binding strength of ORR intermediates on the Fe-N_(4) sites,they suffer from serious mass transport limitations as microporous templates/substrates,i.e.,zeolitic imidazolate frameworks(ZIFs),are usually employed to host the active sites.Motivated by this challenge,we herein develop a hydrogen-bonded organic framework(HOF)-assisted pyrolysis strategy to construct hierarchical micro/mesoporous carbon nanoplates for the deposition of atomically dispersed Fe-N_(4) sites.Such a design is accomplished by employing HOF nanoplates assembled from 2-aminoterephthalic acid(NH_(2)-BDC) and p-phenylenediamine(PDA) as both soft templates and C,N precursors.Benefitting from the structural merits inherited from HOF templates,the optimized catalyst(denoted as Fe-N-C SAC-950) displays outstanding ORR activity with a high half-wave potential of 0.895 V(vs.reversible hydrogen electrode(RHE)) and a small overpotential of 356 mV at 10 mA cm^(-2) for the oxygen evolution reaction(OER).More excitingly,its application potential is further verified by delivering superb rechargeability and cycling stability with a nearly unfading charge-discharge gap of 0.72 V after 160 h.Molecular dynamics(MD) simulations reveal that micro/mesoporous structure is conducive to the rapid mass transfer of O_(2),thus enhancing the ORR performance.In situ Raman results further indicate that the conversion of O_(2) to~*O_(2)-the rate-determining step(RDS) for Fe-N-C SAC-950.This work will provide a versatile strategy to construct single atom catalysts with desirable catalytic properties.展开更多
To achieve high energy density in lithium batteries,the construction of lithium-ion/metal hybrid anodes is a promising strategy.In particular,because of the anisotropy of graphite,hybrid anode formed by graphite/Li me...To achieve high energy density in lithium batteries,the construction of lithium-ion/metal hybrid anodes is a promising strategy.In particular,because of the anisotropy of graphite,hybrid anode formed by graphite/Li metal has low transport kinetics and is easy to causes the growth of lithium dendrites and accumulation of dead Li,which seriously affects the cycle life of batteries and even causes safety problems.Here,by comparing graphite with two types of hard carbon,it was found that hybrid anode formed by hard carbon and lithium metal,possessing more disordered mesoporous structure and lithophilic groups,presents better performance.Results indicate that the mesoporous structure provides abundant active site and storage space for dead lithium.With the synergistic effect of this structure and lithophilic functional groups(–COOH),the reversibility of hard carbon/lithium metal hybrid anode is maintained,promoting uniform deposition of lithium metal and alleviating formation of lithium dendrites.The hybrid anode maintains a 99.5%Coulombic efficiency(CE)after 260 cycles at a specific capacity of 500 m Ah/g.This work provides new insights into the hybrid anodes formed by carbon-based materials and lithium metal with high specific energy and fast charging ability.展开更多
A Y-zeolite-containing composite material with micro/mesoporous structure had been synthesized from kaolin by means of the in-situ crystallization method. The obtained samples were investigated by XRD and BET methods....A Y-zeolite-containing composite material with micro/mesoporous structure had been synthesized from kaolin by means of the in-situ crystallization method. The obtained samples were investigated by XRD and BET methods. Evaluation of catalytic activity of both the commercial Y-zeolite and the novel Y-zeolite-containing composite material was carried out in the pulse micro-chromatography platform with two probe molecules of different molecular sizes: VGO feedstock and 1,3,5 tri-isopropyl benzene. It was found that the Y-zeolite-containing composite material was richer in external surface and meso-/macro-pores; the Y-zeolite-containing composite material demonstrated a smaller rate of deactivation compared to the commercial Y-zeolite.展开更多
FeF3·0.33H2O crystallizes in hexagonal tungsten bronze structure with more opened hexagonal cavities are considered as next generation electrode materials of both lithium ion battery and sodium ion battery.In thi...FeF3·0.33H2O crystallizes in hexagonal tungsten bronze structure with more opened hexagonal cavities are considered as next generation electrode materials of both lithium ion battery and sodium ion battery.In this paper the mesoporous spherical FeF3·0.33H2O/MWCNTs nanocomposite was successfully synthesized via a one-step solvothermal approach. Galvanostatic measurement showed that the performances of sodium ion batteries(SIBs) using FeF3·0.33H2O/MWCNTs as cathode material were highly dependent on the morphology and size of the as-prepared materials. Benefitting from the special mesoporous structure features, FeF3·0.33H2O/MWCNTs nanocomposite exhibits much better electrochemical performances in terms of initial discharge capacity(350.4 mAh g-1) and cycle performance(123.5 mAh g-1 after 50 cycles at 0.1 C range from 1.0 V to 4.0 V) as well as rate capacity(123.8 mAh g-1 after 25 cycles back to 0.1 C). The excellent electrochemical performance enhancement can be attributed to the synergistic effect of the mesoporous structure and the MWCNTs conductive network, which can effectively increase the contact area between the active materials and the electrolyte, shorten the Na+ diffusion pathway,buffer the volume change during cycling/discharge process and improve the structure stability of the FeF3·0.33H2O/MWCNTs nanocomposite.展开更多
Sphere-like mesoporous CdS nanocrystals with high crystallinity and big surface area were successfully fabricated by ultrasound irradiation at room temperature. The as-synthesized CdS with and without ultrasound irra ...Sphere-like mesoporous CdS nanocrystals with high crystallinity and big surface area were successfully fabricated by ultrasound irradiation at room temperature. The as-synthesized CdS with and without ultrasound irra diation was investigated by the characterizations of X-ray diffraction(XRD), scanning electron microscopy(SEM), transmission electron microscopy(TEM), and Brunauer-Emmett-Teller(BET) surface areas. The photocatalytic acti vity of the CdS was evaluated by photocatalytic degradation of methyl orange under visible light(λ〉420 nm) irradia tion. A possible mechanism for the formation of the CdS nanocrystals with mesoporous structure under ultrasound irradiation was proposed. The results show that both the template role of the triblock copolymer of P123 and the effect of ultrasound-induced aggregation are mainly responsible for the formation of mesoporous structure. On the other hand, the energy generated from acoustic cavitation can effectively accelerate the crystallization process of the amorphous CdS.展开更多
Mixture formed from sonicating TiCl4 and Si(OEt)4 in the absence of water is used as precursor and hydrolyzed by using a long-chain organic ammonium bromide as a structure-directing agent. The product, titania-silica,...Mixture formed from sonicating TiCl4 and Si(OEt)4 in the absence of water is used as precursor and hydrolyzed by using a long-chain organic ammonium bromide as a structure-directing agent. The product, titania-silica, is of mesoporous structure and characterized with SEM, FT-IR, BET, XRD and so on.展开更多
Mesoporous La0.8Sr0.2MnO3+σ/z SBA-15(z = 1, 2, 4) perovskite oxides were synthesized via hard-templating with ordered mesoporous silica SBA-15 as the template. The as-prepared samples were characterized by XRD, SE...Mesoporous La0.8Sr0.2MnO3+σ/z SBA-15(z = 1, 2, 4) perovskite oxides were synthesized via hard-templating with ordered mesoporous silica SBA-15 as the template. The as-prepared samples were characterized by XRD, SEM, AFM, BET, and XPS and the catalytic activity was tested for CO oxidation. The wide-angle XRD patterns showed that La0.8Sr0.2MnO3+σ perovskite was formed. The SEM and AFM analyses exhibited that La0.8Sr0.2MnO3+σ by hard-templating method had much smaller particle size(18 nm) than that(40 nm) by the sol-gel method. The perovskite-type oxides La0.8Sr0.2MnO3+σ/z SBA-15(z = 1, 2, 4) also displayed a higher BET surface area from 70 to 143.7 m^2/g and a disordered mesostructure from nitrogen sorption analysis, as well as a small-angle XRD pattern. Moreover, the La0.8Sr0.2MnO3+σ/z SBA-15(z = 1, 2, 4) perovskite exhibited a much higher activity in CO oxidation than the conventional La0.8Sr0.2MnO3+σ perovskite. Further analysis by the means of XPS techniques indicated that the existence of high content of Oads/Olatt species contributed to the high activity.展开更多
Photocatalytic activity of doped polyaniline nanopowders with different molar ratio of An/O (aniline^oxidizer) has been studied in the process of photocatalytic decolorization of aqueous solutions of methylene blue....Photocatalytic activity of doped polyaniline nanopowders with different molar ratio of An/O (aniline^oxidizer) has been studied in the process of photocatalytic decolorization of aqueous solutions of methylene blue. By means of scanning electron microscopy and low-temperature N2 adsorption method, it was found that doped PANI (polyaniline) nanopowders have the particles size of 30-50 nm with the specific surface area of 20-35 m2.g"~. It was found that PANI photocatalytic activity essentially depends on molar ratio of An/O and adsorption interactions between the dye molecules and catalytic active centers on PANI surface and these interactions are greatly affected by pH of the solution 9.2. An optimum of the synergetic effect is found for an initial molar ratio of aniline to oxidizer equal to 0.8.展开更多
Herein,Pd nanoparticles loaded Co_(3)O_(4)catalysts(Pd@Co_(3)O_(4))are constructed from zeolitic imidazolate framework-67(ZIF-67)for the ethanol oxidation reaction(EOR).It is demonstrated for the first time that the e...Herein,Pd nanoparticles loaded Co_(3)O_(4)catalysts(Pd@Co_(3)O_(4))are constructed from zeolitic imidazolate framework-67(ZIF-67)for the ethanol oxidation reaction(EOR).It is demonstrated for the first time that the electrochemical conversion of Co_(3)O_(4)support would result in the charge distribution alignment at the Pd/Co_(3)O_(4)interface and induce the formation of highly reactive Pd-O species(PdO^(*)),which can further catalyze the consequent reactions of the intermediates of the ethanol oxidation.The catalyst,Pd@Co_(3)O_(4)-450,obtained under the optimized conditions exhibits excellent EOR performance with a high mass activity of 590 mA mg-1,prominent operational stability,and extraordinary capability for the electro-oxidation of acetaldehyde intermediates.Importantly,the detailed mechanism investigation reveals that Pd@Co_(3)O_(4)-450 could be benefit to the C-C bond cleavage to promote the desirable C1 pathway for the ethanol oxidation reaction.The present strategy based on the metal-support interaction of the catalyst might provide valuable inspiration for the design of high-performing catalysts for the ethanol oxidation reaction.展开更多
As high-energy cathode materials,conversion-type metal fluorides provide a prospective pathway for developing next-generation lithium-ion batteries.However,they suffer from severe performance decay owing to continuous...As high-energy cathode materials,conversion-type metal fluorides provide a prospective pathway for developing next-generation lithium-ion batteries.However,they suffer from severe performance decay owing to continuous structural destruction and active material dissolution upon cycling,which worsen at elevated temperatures.Here,we design a novel FeF2 cathode with in situ polymerized solid-state electrolyte systems to enhance the cycling ability of metal fluorides at 60 C.Novel FeF2 with a mesoporous structure(meso-FeF2)improves Liþdiffusion and relieves the volume change that typically occurs during the alternating conversion reactions.The structural stability of the meso-FeF2 cathode is strengthened by an in situ polymerized solid-state electrolyte,which prevents the pulverization and ion dissolution that are inevitable for conventional liquid electrolytes.Under the double action of this in situ polymerized solid-state electrolyte and the meso-FeF2's mesoporous structure,the active material maintains an intact SEI layer and part of the mesoporous structure after long charge–discharge cycling,showing excellent cycling stability at high temperatures.展开更多
Three-dimensional(3D)ordered mesoporous MnO2 was prepared using KIT-6 mesoporous molecular sieves as a hard template.The material was used for catalytic oxidation of HCHO.The material has high surface areas and the ...Three-dimensional(3D)ordered mesoporous MnO2 was prepared using KIT-6 mesoporous molecular sieves as a hard template.The material was used for catalytic oxidation of HCHO.The material has high surface areas and the mesoporous characteristics of the template,with cubic symmetry(ia3d).It consists of a β-MnO2 crystalline phase corresponding to pyrolusite,with a rutile structure.Transmission electron microscopy and X-ray photoelectron spectroscopy showed that the 3D-MnO2 catalyst has a large number of exposed Mn4+ ions on the(110)crystal plane surfaces,with a lattice spacing of 0.311 nm; this enhances oxidation of HCHO.Complete conversion of HCHO to CO2 and H2O was achieved at 130 °C on 3D-MnO2; the same conversions on α-MnO2 and β-MnO2 nanorods were obtained at 140 and 180 °C,respectively,under the same conditions.The specific mesoporous structure,high specific surface area,and large number of surface Mn4+ ions are responsible for the catalytic activity of 3D-MnO2 in HCHO oxidation.展开更多
Li3V2(PO4)3 precursor was obtained with V2Os.nH2O , LiOH'H2O, NH4H2PO4 and sucrose as starting materials by grinding-sol-gel method, and then the monoclinic-typed Li3Vz(PO4)3 cathode material was prepared by sint...Li3V2(PO4)3 precursor was obtained with V2Os.nH2O , LiOH'H2O, NH4H2PO4 and sucrose as starting materials by grinding-sol-gel method, and then the monoclinic-typed Li3Vz(PO4)3 cathode material was prepared by sintering the amorphous Li3V2(PO4)3. The as-sintered samples were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption-desorption and electrochemical measurement. It is found that Li3Vz(PO4)3 sintered at 700 ℃ possesses good wormhole-like mesoporous structure with the largest specific surface area of 188 cmZ/g, and the smallest pore size of 9.3 nm. Electrochemical test reveals that the initial discharge capacity of the 700 ℃ sintered sample is 155.9 mA.h/g at the rate of 0.2C, and the capacity retains 154 mA.h/g after 50 cycles, exhibiting a stable discharge capacity at room temperature.展开更多
An Fe/TiO2catalyst with uniform mesopores was synthesized using Pluronic F127as a structuredirecting agent.This catalyst was used for selective catalytic reduction of NO with NH3.The catalytic activity and resistance ...An Fe/TiO2catalyst with uniform mesopores was synthesized using Pluronic F127as a structuredirecting agent.This catalyst was used for selective catalytic reduction of NO with NH3.The catalytic activity and resistance to H2O and SO2of Fe/TiO2prepared by a template method were better than those of catalysts synthesized using impregnation and coprecipitation.The samples were characterized using N2‐physisorption,transmission electron microscopy,ultraviolet‐visibl spectroscopy,X‐ray photoelectron spectroscopy,and in situ diffuse reflectance infrared Fouriertransform spectroscopy.The results showed that Pluronic F127acted as a structural and chemical promoter;it not only promoted the formation of a uniform mesoporous structure,leading to a higher surface area,but also improved dispersion of the active phase.In addition,the larger number of Lewis acidic sites,indicated by the presence of coordinated NH3species(1188cm-1)and the N–H stretching modes of coordinated NH3(3242and3388cm-1),were beneficial to mid‐temperature selective catalytic reduction reactions.展开更多
Highly ordered mesoporous NiMoO4 material was successfully synthesized using mesoporous silica KIT-6 as hard template via vacuum nanocasting method. The structure was characterized by means of XRD, TEM, N2 adsorption-...Highly ordered mesoporous NiMoO4 material was successfully synthesized using mesoporous silica KIT-6 as hard template via vacuum nanocasting method. The structure was characterized by means of XRD, TEM, N2 adsorption-desorption, Raman and FT-IR. The mesoporous NiMoO4 with the coexistence of a-NiMoO4 and fl-NiMoO4 showed well-ordered mesoporous structure, a bimodal pore size distribution and crystalline framework. The catalytic performance of NiMoOa was investigated for oxidative dehydrogenation of propane. It is demonstrated that the mesoporous NiMoO4 catalyst with more surface active oxygen species showed better catalytic performance in oxidative dehydrogena- tion of propane in comparison with bulk NiMoO4.展开更多
A carbon-based sulfonated catalyst was prepared by direct sulfonation and carbonization (in moderate conditions:200 °C, 12 h) of red liquor solids, a by-product of paper-making process. The prepared sulfonate...A carbon-based sulfonated catalyst was prepared by direct sulfonation and carbonization (in moderate conditions:200 °C, 12 h) of red liquor solids, a by-product of paper-making process. The prepared sulfonated cata-lyst (SC) had aromatic structure, composed of carbon enriched inner core, and oxygen-containing (SO3H, COOH, OH) groups enriched surface. The SO3H, COOH, OH groups amounted to 0.74 mmol·g^-1, 0.78 mmol·g^-1, 2.18 mmol·g^-1, respectively. The fresh SC showed much higher catalytic activity than that of the traditional solid acid catalysts (strong-acid 732 cation exchange resin, hydrogen type zeolite socony mobile-five (HZSM-5), sulfated zir-conia) in esterification of oleic acid. SC was deactivated during the reactions, through the mechanisms of leaching of sulfonated species and formation of sulfonate esters. Two regeneration methods were developed, and the catalytic activity can be mostly regenerated by regeneration Method 1 and be fully regenerated by regeneration Method 2, respectively.展开更多
Perovskite solar cells(PSCs) have emerged as one of the most promising candidates for photovoltaic applications. Low-cost, low-temperature solution processes including coating and printing techniques makes PSCs promis...Perovskite solar cells(PSCs) have emerged as one of the most promising candidates for photovoltaic applications. Low-cost, low-temperature solution processes including coating and printing techniques makes PSCs promising for the greatly potential commercialization due to the scalability and compatibility with large-scale, roll-to-roll manufacturing processes. In this review, we focus on the solution deposition of charge transport layers and perovskite absorption layer in both mesoporous and planar structural PSC devices. Furthermore, the most recent design strategies via solution deposition are presented as well, which have been explored to enlarge the active area, enhance the crystallization and passivate the defects, leading to the performance improvement of PSC devices.展开更多
Improving catalytic performance is a yet still challenge in thermal catalytic oxidation.Herein,uniform mesoporous MnO_(2) nanospheresupported bimetallic Pt–Pd nanoparticles were successfully fabricated via a SiO_(2) ...Improving catalytic performance is a yet still challenge in thermal catalytic oxidation.Herein,uniform mesoporous MnO_(2) nanospheresupported bimetallic Pt–Pd nanoparticles were successfully fabricated via a SiO_(2) template strategy for the total catalytic degradation of volatile organic compounds at low temperature.The introduction of mesopores into the MnO_(2) support induces a large specific surface area and pore size,thus providing numerous accessible active sites and enhanced diffusion properties.Moreover,the addition of a secondary noble metal can adjust the O_(ads)/O_(latt) molar ratios,resulting in high catalytic activity.Among them,the catalyst having a Pt/Pd molar ratio of 7:3 exhibits optimized catalytic activity at a weight hourly space velocity of 36,000 mL g^(-1) h^(-1),reaching 100%toluene oxidation at 175℃ with a lower activation energy(57.0 kJ mol^(-1))than the corresponding monometallic Pt or non-Pt-based catalysts(93.8 kJ mol^(-1) and 214.2 kJ mol^(-1)).Our findings demonstrate that the uniform mesoporous MnO_(2) nanosphere-supported bimetallic Pt–Pd nanoparticles catalyst is an effective candidate for application in elimination of toluene.展开更多
CaO-based sorbent is considered to be a promising candidate for capturing CO_2 at high temperature. However,the adsorption capacity of CaO decreases sharply with the increase of the carbonation/calcination cycles. In ...CaO-based sorbent is considered to be a promising candidate for capturing CO_2 at high temperature. However,the adsorption capacity of CaO decreases sharply with the increase of the carbonation/calcination cycles. In this study, CaO was derived from calcium acetate(CaAc_2), which was doped with different elements(Mg, Al,Ce, Zr and La) to improve the cyclic stability. The carbonation conversion and cyclic stability of sorbents were tested by thermogravimetric analyzer(TGA). The sorbents were characterized by N_2 isothermal adsorption measurements, scanning electron microscopy(SEM) and X-ray diffraction(XRD). The results showed that the cyclic stabilities of all modified sorbents were improved by doping elements, while the carbonation conversions of sorbents in the 1st cycle were not increased by doping different elements. After 22 cycles, the cyclic stabilities of CaO–Al, CaO–Ce and CaO–La were above 96.2%. After 110 cycles, the cyclic stability of CaO–Al was still as high as 87.1%. Furthermore, the carbonation conversion was closely related to the critical time and specific surface area.展开更多
基金Projects(51102285,81170912)supported by the National Natural Science Foundation of ChinaProject supported by the Open Foundation of State Key Laboratory of Powder Metallurgy,China
文摘The mesoporous hydroxyapatite (HA) was synthesized by hydrothermal method utilizing cationic surfactant cetyltrimethylammonium bromide (CTAB) as template. The crystalline phase, morphology and porous structure were characterized respectively by different detecting techniques. The results reveal that the particles are highly crystalline hydroxyapatite phase. The surfactant has little influence on the morphology of the crystals, but affects the porous structure obviously. The sample without CTAB has a low surface area not exceeding 33 m^2/g, and no distinct pores can be observed by TEM. While the samples obtained with the surfactant get better parameters. Numerous open-ended pores centered at 2-7 nm spread unequally on the surface of the hydroxyapatite nanorods. The N2 adsorption-desorption experiments show type IV isotherms with distinct hysteresis loops, illustrating the presence of mesoporous structure. When the mole ratio of CTAB to HA is 1:2, the sample has the largest surface area of 97.1 m^2/g and pore volume of 0.466 cm^3/g.
基金Ministry of Trade,Industry and Energy,Grant/Award Number:20010095Korea Evaluation Institute of Industrial Technology,Grant/Award Number:20012341。
文摘Lithium-sulfur batteries(LSBs)have drawn significant attention owing to their high theoretical discharge capacity and energy density.However,the dissolution of long-chain polysulfides into the electrolyte during the charge and discharge process(“shuttle effect”)results in fast capacity fading and inferior electrochemical performance.In this study,Mn_(2)O_(3)with an ordered mesoporous structure(OM-Mn_(2)O_(3))was designed as a cathode host for LSBs via KIT-6 hard templating,to effectively inhibit the polysulfide shuttle effect.OM-Mn_(2)O_(3)offers numerous pores to confine sulfur and tightly anchor the dissolved polysulfides through the combined effects of strong polar-polar interactions,polysulfides,and sulfur chain catenation.The OM-Mn_(2)O_(3)/S composite electrode delivered a discharge capacity of 561 mAh g^(-1) after 250 cycles at 0.5 C owing to the excellent performance of OM-Mn_(2)O_(3).Furthermore,it retained a discharge capacity of 628mA h g^(-1) even at a rate of 2 C,which was significantly higher than that of a pristine sulfur electrode(206mA h g^(-1)).These findings provide a prospective strategy for designing cathode materials for high-performance LSBs.
基金financially supported by the National Key R&D Program of China(2022YFB4004100)the National Natural Science Foundation of China(22272161)+6 种基金the Jilin Province Science and Technology Development Program(20230101367JC)financially supported by the National Natural Science Foundation of China(22073094)the Science and Technology Development Program of Jilin Province(20210402059GH)the Science and Technology Plan Projects of Yunnan Province(202101BC070001–007)the Major Science and Technology Projects for Independent Innovation of China FAW Group Co.,Ltd(20220301018GX)the essential support of the Network and Computing Center,CIAC,CASthe Computing Center of Jilin Province。
文摘Developing cost-effective,robust and stable non-precious metal catalysts for oxygen reduction reaction(ORR) is of paramount importance for electrochemical energy conversion devices such as fuel cells and metal-air batteries.Although Fe-N-C single atom catalysts(SACs) have been hailed as the most promising candidate due to the optimal binding strength of ORR intermediates on the Fe-N_(4) sites,they suffer from serious mass transport limitations as microporous templates/substrates,i.e.,zeolitic imidazolate frameworks(ZIFs),are usually employed to host the active sites.Motivated by this challenge,we herein develop a hydrogen-bonded organic framework(HOF)-assisted pyrolysis strategy to construct hierarchical micro/mesoporous carbon nanoplates for the deposition of atomically dispersed Fe-N_(4) sites.Such a design is accomplished by employing HOF nanoplates assembled from 2-aminoterephthalic acid(NH_(2)-BDC) and p-phenylenediamine(PDA) as both soft templates and C,N precursors.Benefitting from the structural merits inherited from HOF templates,the optimized catalyst(denoted as Fe-N-C SAC-950) displays outstanding ORR activity with a high half-wave potential of 0.895 V(vs.reversible hydrogen electrode(RHE)) and a small overpotential of 356 mV at 10 mA cm^(-2) for the oxygen evolution reaction(OER).More excitingly,its application potential is further verified by delivering superb rechargeability and cycling stability with a nearly unfading charge-discharge gap of 0.72 V after 160 h.Molecular dynamics(MD) simulations reveal that micro/mesoporous structure is conducive to the rapid mass transfer of O_(2),thus enhancing the ORR performance.In situ Raman results further indicate that the conversion of O_(2) to~*O_(2)-the rate-determining step(RDS) for Fe-N-C SAC-950.This work will provide a versatile strategy to construct single atom catalysts with desirable catalytic properties.
基金Financial support from the National Natural Science Foundation of China (22075320)。
文摘To achieve high energy density in lithium batteries,the construction of lithium-ion/metal hybrid anodes is a promising strategy.In particular,because of the anisotropy of graphite,hybrid anode formed by graphite/Li metal has low transport kinetics and is easy to causes the growth of lithium dendrites and accumulation of dead Li,which seriously affects the cycle life of batteries and even causes safety problems.Here,by comparing graphite with two types of hard carbon,it was found that hybrid anode formed by hard carbon and lithium metal,possessing more disordered mesoporous structure and lithophilic groups,presents better performance.Results indicate that the mesoporous structure provides abundant active site and storage space for dead lithium.With the synergistic effect of this structure and lithophilic functional groups(–COOH),the reversibility of hard carbon/lithium metal hybrid anode is maintained,promoting uniform deposition of lithium metal and alleviating formation of lithium dendrites.The hybrid anode maintains a 99.5%Coulombic efficiency(CE)after 260 cycles at a specific capacity of 500 m Ah/g.This work provides new insights into the hybrid anodes formed by carbon-based materials and lithium metal with high specific energy and fast charging ability.
文摘A Y-zeolite-containing composite material with micro/mesoporous structure had been synthesized from kaolin by means of the in-situ crystallization method. The obtained samples were investigated by XRD and BET methods. Evaluation of catalytic activity of both the commercial Y-zeolite and the novel Y-zeolite-containing composite material was carried out in the pulse micro-chromatography platform with two probe molecules of different molecular sizes: VGO feedstock and 1,3,5 tri-isopropyl benzene. It was found that the Y-zeolite-containing composite material was richer in external surface and meso-/macro-pores; the Y-zeolite-containing composite material demonstrated a smaller rate of deactivation compared to the commercial Y-zeolite.
基金supported financially by the National Natural Science Foundation of China under project (no. 51272221)the Key Project of Strategic New Industry of Hunan Province under project (nos. 2016GK4005 and 2016GK4030)
文摘FeF3·0.33H2O crystallizes in hexagonal tungsten bronze structure with more opened hexagonal cavities are considered as next generation electrode materials of both lithium ion battery and sodium ion battery.In this paper the mesoporous spherical FeF3·0.33H2O/MWCNTs nanocomposite was successfully synthesized via a one-step solvothermal approach. Galvanostatic measurement showed that the performances of sodium ion batteries(SIBs) using FeF3·0.33H2O/MWCNTs as cathode material were highly dependent on the morphology and size of the as-prepared materials. Benefitting from the special mesoporous structure features, FeF3·0.33H2O/MWCNTs nanocomposite exhibits much better electrochemical performances in terms of initial discharge capacity(350.4 mAh g-1) and cycle performance(123.5 mAh g-1 after 50 cycles at 0.1 C range from 1.0 V to 4.0 V) as well as rate capacity(123.8 mAh g-1 after 25 cycles back to 0.1 C). The excellent electrochemical performance enhancement can be attributed to the synergistic effect of the mesoporous structure and the MWCNTs conductive network, which can effectively increase the contact area between the active materials and the electrolyte, shorten the Na+ diffusion pathway,buffer the volume change during cycling/discharge process and improve the structure stability of the FeF3·0.33H2O/MWCNTs nanocomposite.
基金Supported by the National Natural Science Foundation of China(No.21067004)the Natural Science Foundation of Jiangxi Province, China(No.2010GZH0048)the Open Foundation of State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, China(No.200906)
文摘Sphere-like mesoporous CdS nanocrystals with high crystallinity and big surface area were successfully fabricated by ultrasound irradiation at room temperature. The as-synthesized CdS with and without ultrasound irra diation was investigated by the characterizations of X-ray diffraction(XRD), scanning electron microscopy(SEM), transmission electron microscopy(TEM), and Brunauer-Emmett-Teller(BET) surface areas. The photocatalytic acti vity of the CdS was evaluated by photocatalytic degradation of methyl orange under visible light(λ〉420 nm) irradia tion. A possible mechanism for the formation of the CdS nanocrystals with mesoporous structure under ultrasound irradiation was proposed. The results show that both the template role of the triblock copolymer of P123 and the effect of ultrasound-induced aggregation are mainly responsible for the formation of mesoporous structure. On the other hand, the energy generated from acoustic cavitation can effectively accelerate the crystallization process of the amorphous CdS.
文摘Mixture formed from sonicating TiCl4 and Si(OEt)4 in the absence of water is used as precursor and hydrolyzed by using a long-chain organic ammonium bromide as a structure-directing agent. The product, titania-silica, is of mesoporous structure and characterized with SEM, FT-IR, BET, XRD and so on.
文摘Mesoporous La0.8Sr0.2MnO3+σ/z SBA-15(z = 1, 2, 4) perovskite oxides were synthesized via hard-templating with ordered mesoporous silica SBA-15 as the template. The as-prepared samples were characterized by XRD, SEM, AFM, BET, and XPS and the catalytic activity was tested for CO oxidation. The wide-angle XRD patterns showed that La0.8Sr0.2MnO3+σ perovskite was formed. The SEM and AFM analyses exhibited that La0.8Sr0.2MnO3+σ by hard-templating method had much smaller particle size(18 nm) than that(40 nm) by the sol-gel method. The perovskite-type oxides La0.8Sr0.2MnO3+σ/z SBA-15(z = 1, 2, 4) also displayed a higher BET surface area from 70 to 143.7 m^2/g and a disordered mesostructure from nitrogen sorption analysis, as well as a small-angle XRD pattern. Moreover, the La0.8Sr0.2MnO3+σ/z SBA-15(z = 1, 2, 4) perovskite exhibited a much higher activity in CO oxidation than the conventional La0.8Sr0.2MnO3+σ perovskite. Further analysis by the means of XPS techniques indicated that the existence of high content of Oads/Olatt species contributed to the high activity.
文摘Photocatalytic activity of doped polyaniline nanopowders with different molar ratio of An/O (aniline^oxidizer) has been studied in the process of photocatalytic decolorization of aqueous solutions of methylene blue. By means of scanning electron microscopy and low-temperature N2 adsorption method, it was found that doped PANI (polyaniline) nanopowders have the particles size of 30-50 nm with the specific surface area of 20-35 m2.g"~. It was found that PANI photocatalytic activity essentially depends on molar ratio of An/O and adsorption interactions between the dye molecules and catalytic active centers on PANI surface and these interactions are greatly affected by pH of the solution 9.2. An optimum of the synergetic effect is found for an initial molar ratio of aniline to oxidizer equal to 0.8.
基金supported by the National Natural Science Foundation of China(21336005)the Ministry of Science and Technology of China(2014EG111224)+1 种基金the National Key R&D Program of China(2021YFB4001200)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX22_3185)。
文摘Herein,Pd nanoparticles loaded Co_(3)O_(4)catalysts(Pd@Co_(3)O_(4))are constructed from zeolitic imidazolate framework-67(ZIF-67)for the ethanol oxidation reaction(EOR).It is demonstrated for the first time that the electrochemical conversion of Co_(3)O_(4)support would result in the charge distribution alignment at the Pd/Co_(3)O_(4)interface and induce the formation of highly reactive Pd-O species(PdO^(*)),which can further catalyze the consequent reactions of the intermediates of the ethanol oxidation.The catalyst,Pd@Co_(3)O_(4)-450,obtained under the optimized conditions exhibits excellent EOR performance with a high mass activity of 590 mA mg-1,prominent operational stability,and extraordinary capability for the electro-oxidation of acetaldehyde intermediates.Importantly,the detailed mechanism investigation reveals that Pd@Co_(3)O_(4)-450 could be benefit to the C-C bond cleavage to promote the desirable C1 pathway for the ethanol oxidation reaction.The present strategy based on the metal-support interaction of the catalyst might provide valuable inspiration for the design of high-performing catalysts for the ethanol oxidation reaction.
基金financially supported by the National Key R&D Program of China(No.2022YFB3805702)the State Key Program of the National Natural Science Foundation of China(No.52130303)the National Natural Science Foundation of China(Nos.51973152,51973119,52103093,and 52173078).
文摘As high-energy cathode materials,conversion-type metal fluorides provide a prospective pathway for developing next-generation lithium-ion batteries.However,they suffer from severe performance decay owing to continuous structural destruction and active material dissolution upon cycling,which worsen at elevated temperatures.Here,we design a novel FeF2 cathode with in situ polymerized solid-state electrolyte systems to enhance the cycling ability of metal fluorides at 60 C.Novel FeF2 with a mesoporous structure(meso-FeF2)improves Liþdiffusion and relieves the volume change that typically occurs during the alternating conversion reactions.The structural stability of the meso-FeF2 cathode is strengthened by an in situ polymerized solid-state electrolyte,which prevents the pulverization and ion dissolution that are inevitable for conventional liquid electrolytes.Under the double action of this in situ polymerized solid-state electrolyte and the meso-FeF2's mesoporous structure,the active material maintains an intact SEI layer and part of the mesoporous structure after long charge–discharge cycling,showing excellent cycling stability at high temperatures.
基金supported by the National Natural Science Foundation of China(21325731,21221004 and 51478241)~~
文摘Three-dimensional(3D)ordered mesoporous MnO2 was prepared using KIT-6 mesoporous molecular sieves as a hard template.The material was used for catalytic oxidation of HCHO.The material has high surface areas and the mesoporous characteristics of the template,with cubic symmetry(ia3d).It consists of a β-MnO2 crystalline phase corresponding to pyrolusite,with a rutile structure.Transmission electron microscopy and X-ray photoelectron spectroscopy showed that the 3D-MnO2 catalyst has a large number of exposed Mn4+ ions on the(110)crystal plane surfaces,with a lattice spacing of 0.311 nm; this enhances oxidation of HCHO.Complete conversion of HCHO to CO2 and H2O was achieved at 130 °C on 3D-MnO2; the same conversions on α-MnO2 and β-MnO2 nanorods were obtained at 140 and 180 °C,respectively,under the same conditions.The specific mesoporous structure,high specific surface area,and large number of surface Mn4+ ions are responsible for the catalytic activity of 3D-MnO2 in HCHO oxidation.
基金Project (51162026) supported by the National Natural Science Foundation of ChinaProjects (20100480949, 201104509) supported by China Postdoctoral Science FoundationProject (133274341015501) supported by Postdoctoral Science Foundation of Central South University, China
文摘Li3V2(PO4)3 precursor was obtained with V2Os.nH2O , LiOH'H2O, NH4H2PO4 and sucrose as starting materials by grinding-sol-gel method, and then the monoclinic-typed Li3Vz(PO4)3 cathode material was prepared by sintering the amorphous Li3V2(PO4)3. The as-sintered samples were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption-desorption and electrochemical measurement. It is found that Li3Vz(PO4)3 sintered at 700 ℃ possesses good wormhole-like mesoporous structure with the largest specific surface area of 188 cmZ/g, and the smallest pore size of 9.3 nm. Electrochemical test reveals that the initial discharge capacity of the 700 ℃ sintered sample is 155.9 mA.h/g at the rate of 0.2C, and the capacity retains 154 mA.h/g after 50 cycles, exhibiting a stable discharge capacity at room temperature.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA07030300)~~
文摘An Fe/TiO2catalyst with uniform mesopores was synthesized using Pluronic F127as a structuredirecting agent.This catalyst was used for selective catalytic reduction of NO with NH3.The catalytic activity and resistance to H2O and SO2of Fe/TiO2prepared by a template method were better than those of catalysts synthesized using impregnation and coprecipitation.The samples were characterized using N2‐physisorption,transmission electron microscopy,ultraviolet‐visibl spectroscopy,X‐ray photoelectron spectroscopy,and in situ diffuse reflectance infrared Fouriertransform spectroscopy.The results showed that Pluronic F127acted as a structural and chemical promoter;it not only promoted the formation of a uniform mesoporous structure,leading to a higher surface area,but also improved dispersion of the active phase.In addition,the larger number of Lewis acidic sites,indicated by the presence of coordinated NH3species(1188cm-1)and the N–H stretching modes of coordinated NH3(3242and3388cm-1),were beneficial to mid‐temperature selective catalytic reduction reactions.
基金supported by NSFC(21073235,21173270,21177160,21376261)863 Program(2013AA065302)PetroChina Innovation Foundation(2011D-5006-0403)
文摘Highly ordered mesoporous NiMoO4 material was successfully synthesized using mesoporous silica KIT-6 as hard template via vacuum nanocasting method. The structure was characterized by means of XRD, TEM, N2 adsorption-desorption, Raman and FT-IR. The mesoporous NiMoO4 with the coexistence of a-NiMoO4 and fl-NiMoO4 showed well-ordered mesoporous structure, a bimodal pore size distribution and crystalline framework. The catalytic performance of NiMoOa was investigated for oxidative dehydrogenation of propane. It is demonstrated that the mesoporous NiMoO4 catalyst with more surface active oxygen species showed better catalytic performance in oxidative dehydrogena- tion of propane in comparison with bulk NiMoO4.
基金Supported by the National Natural Science Foundation of China(21276076)the Fundamental Research Funds for the Central Universities of China(WA1014003)State Key Laboratory of Chemical Engineering(SKL-ChE-10C06)
文摘A carbon-based sulfonated catalyst was prepared by direct sulfonation and carbonization (in moderate conditions:200 °C, 12 h) of red liquor solids, a by-product of paper-making process. The prepared sulfonated cata-lyst (SC) had aromatic structure, composed of carbon enriched inner core, and oxygen-containing (SO3H, COOH, OH) groups enriched surface. The SO3H, COOH, OH groups amounted to 0.74 mmol·g^-1, 0.78 mmol·g^-1, 2.18 mmol·g^-1, respectively. The fresh SC showed much higher catalytic activity than that of the traditional solid acid catalysts (strong-acid 732 cation exchange resin, hydrogen type zeolite socony mobile-five (HZSM-5), sulfated zir-conia) in esterification of oleic acid. SC was deactivated during the reactions, through the mechanisms of leaching of sulfonated species and formation of sulfonate esters. Two regeneration methods were developed, and the catalytic activity can be mostly regenerated by regeneration Method 1 and be fully regenerated by regeneration Method 2, respectively.
基金Projects(51673214,51673218,61774170)supported by the National Natural Science Foundation of ChinaProject(2017YFA0206600)supported by the National Key Research and Development Program of China。
文摘Perovskite solar cells(PSCs) have emerged as one of the most promising candidates for photovoltaic applications. Low-cost, low-temperature solution processes including coating and printing techniques makes PSCs promising for the greatly potential commercialization due to the scalability and compatibility with large-scale, roll-to-roll manufacturing processes. In this review, we focus on the solution deposition of charge transport layers and perovskite absorption layer in both mesoporous and planar structural PSC devices. Furthermore, the most recent design strategies via solution deposition are presented as well, which have been explored to enlarge the active area, enhance the crystallization and passivate the defects, leading to the performance improvement of PSC devices.
基金financial support provided by the National Key R&D Program of China(2017YFC0210901,2017YFC0210906)National Natural Science Foundation of China(51573122,21722607,21776190)+2 种基金Natural Science Foundation of the Jiangsu Higher Education Institutions of China(17KJA430014,17KJA150009)the Science and Technology Program for Social Development of Jiangsu(BE2015637)the project supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Improving catalytic performance is a yet still challenge in thermal catalytic oxidation.Herein,uniform mesoporous MnO_(2) nanospheresupported bimetallic Pt–Pd nanoparticles were successfully fabricated via a SiO_(2) template strategy for the total catalytic degradation of volatile organic compounds at low temperature.The introduction of mesopores into the MnO_(2) support induces a large specific surface area and pore size,thus providing numerous accessible active sites and enhanced diffusion properties.Moreover,the addition of a secondary noble metal can adjust the O_(ads)/O_(latt) molar ratios,resulting in high catalytic activity.Among them,the catalyst having a Pt/Pd molar ratio of 7:3 exhibits optimized catalytic activity at a weight hourly space velocity of 36,000 mL g^(-1) h^(-1),reaching 100%toluene oxidation at 175℃ with a lower activation energy(57.0 kJ mol^(-1))than the corresponding monometallic Pt or non-Pt-based catalysts(93.8 kJ mol^(-1) and 214.2 kJ mol^(-1)).Our findings demonstrate that the uniform mesoporous MnO_(2) nanosphere-supported bimetallic Pt–Pd nanoparticles catalyst is an effective candidate for application in elimination of toluene.
基金Supported by Capture CO_2 and Storage Technology Jointly Studied by USA and China(2013DFB60140-04)Northwest University Graduate Innovative Talent Training Project(YZZ12036)
文摘CaO-based sorbent is considered to be a promising candidate for capturing CO_2 at high temperature. However,the adsorption capacity of CaO decreases sharply with the increase of the carbonation/calcination cycles. In this study, CaO was derived from calcium acetate(CaAc_2), which was doped with different elements(Mg, Al,Ce, Zr and La) to improve the cyclic stability. The carbonation conversion and cyclic stability of sorbents were tested by thermogravimetric analyzer(TGA). The sorbents were characterized by N_2 isothermal adsorption measurements, scanning electron microscopy(SEM) and X-ray diffraction(XRD). The results showed that the cyclic stabilities of all modified sorbents were improved by doping elements, while the carbonation conversions of sorbents in the 1st cycle were not increased by doping different elements. After 22 cycles, the cyclic stabilities of CaO–Al, CaO–Ce and CaO–La were above 96.2%. After 110 cycles, the cyclic stability of CaO–Al was still as high as 87.1%. Furthermore, the carbonation conversion was closely related to the critical time and specific surface area.