A treatment unit packed by granular adsorbent of Fe-Mn binary oxide incorporated into diatomite （FMBO（1：1）-diatomite） was studied to remove arsenic from anaerobic groundwater without any pre-treatment or post-tre...A treatment unit packed by granular adsorbent of Fe-Mn binary oxide incorporated into diatomite （FMBO（1：1）-diatomite） was studied to remove arsenic from anaerobic groundwater without any pre-treatment or post-treatment. The raw anaerobic groundwater containing 35-45 μg/L of arsenic was collected from suburb of Beijing. Arsenic（Ⅲ） constituted roughly 60%-80% of the total arsenic content. Approximately 7,000 bed volumes （ratio of effluent volume to adsorbent volume） treated water with arsenic concentration below 10 μg/L were produced in the operation period of four months. The regeneration of FMBO（1：1）-diatomite had been operated for 15 times. In the first stage, the regeneration process significantly improved the adsorption capacity of FMBO（1：1 ）-diatomite. With increased loading amount of Fe-Mn binary oxide, the adsorption capacity for arsenic decreased 20%-40%. Iron and manganese in anaerobic groundwater were oxidized and adsorptive filtrated by FMBO（1 ： 1）-diatomite efficiently. The final concentrations of iron and manganese in effluents were nearly zero. The continued safe performance of the treatment units proved that adsorbent FMBO（1：1）- diatomite had high oxidation ability and exhibited strong adsorptive filtration.展开更多
A rational integration of multiple reactive centers into a combined unit to facilitate their cooperative effects is a smart approach for accelerating the catalytic activity.Here,to achieve this goal,linear imidazolium...A rational integration of multiple reactive centers into a combined unit to facilitate their cooperative effects is a smart approach for accelerating the catalytic activity.Here,to achieve this goal,linear imidazolium-based ionic polymers were confined into the nanopores of mesoporous silica nanospheres anchored with homogeneously distributed zinc salts.Owing to the flexible character and the reinforced cooperative effects of the ionic liquid(nucleophile)and zinc species(Lewis acid)in the confined mesoporous structure,the resultant composite exhibited dramatically improved catalytic performance in the cycloaddition of CO2 with epoxides to form cyclic carbonates.This was in contrast to that observed for the individual catalytic components.Moreover,such a solid catalyst could be easily recovered and reused four times without a significant loss of activity.展开更多
Electrochemical CO_(2) reduction reaction(CO_(2)RR)offers a promising strategy for CO_(2) conversion into value-added C2+products and facilitates the storage of renewable resources under comparatively mild conditions,...Electrochemical CO_(2) reduction reaction(CO_(2)RR)offers a promising strategy for CO_(2) conversion into value-added C2+products and facilitates the storage of renewable resources under comparatively mild conditions,but still remains a challenge.Herein,we propose the strategy of surface reconstruction and interface integration engineering to construct tuneable Cu^(0)-Cu^(+)-Cu^(2+)sites and oxygen vacancy oxide derived from CeO_(2)/CuO nanosheets(OD-CeO_(2)/CuO NSs)heterojunction catalysts and promote the activity and selectivity of CO_(2)RR.The optimized OD-CeO_(2)/CuO electrocatalyst shows the maximum Faradic efficiencies for C2+products in the H-type cell,which reaches 69.8%at−1.25 V versus a reversible hydrogen electrode(RHE).Advanced characterization analysis and density functional theory(DFT)calculations further confirm the fact that the existence of oxygen vacancies and Cu^(0)-Cu^(+)-Cu^(2+)sites modified with CeO_(2) is conducive to CO_(2) adsorption and activation,enhances the hydrogenation of^(*)CO to^(*)CHO,and further promotes the dimerization of^(*)CHO,thus promoting the selectivity of C2+generation.This facile interface integration and surface reconstruction strategy provides an ideal strategy to guide the design of CO_(2)RR electrocatalysts.展开更多
Pt-Au alloy nanowires have been controllably electrodeposited on microelectrodes by applying an al- ternating current and were used as the electrocatalyst for formic acid oxidation. The frequency and voltage of the al...Pt-Au alloy nanowires have been controllably electrodeposited on microelectrodes by applying an al- ternating current and were used as the electrocatalyst for formic acid oxidation. The frequency and voltage of the alternating current and the electrolyte composition were adjusted to precisely control the mor- phologies, alloying structures and composition. The characteristics of Pt-Au alloy nanowires were analyzed by scanning electron microscopy, X-ray diffraction and transmission electron spectroscopy. Electrocatalytic performance of formic acid oxidation at Pt-Au alloy nanowires electrode was investigated by cyclic voltammetry and chronoamperometry. The results showed that the Pt-Au alloy nanowires possessed highly- crystalline morphologies, the controllable bimetallic composition and single-phase alloy structures, which mainly grow in the 〈111〉 crystal orientation. The electrocatalytic activity of formic acid oxidation strongly depended on the bimetallic Pt/Au composition. The PtjsAu6s alloy nanowires displayed superior electrocatalytic performance and high stability toward the electrooxidation of formic acid in acidic so- lution, owing to the ensemble effect of the Pt and Au components. These findings provided insights into the design of the Pt-Au bimetallic nanomaterials as electrocatalvsts for formic acid oxidation.展开更多
The development of carbon materials with high electrochemical performance for next-generation energy device is emerging, especially N, S co-doped carbon materials have sparked intensive attention. However,the explorat...The development of carbon materials with high electrochemical performance for next-generation energy device is emerging, especially N, S co-doped carbon materials have sparked intensive attention. However,the exploration of N, S co-doped carbon with well-defined active sites and hierarchical porous structures are still limited. In this study, we prepared a series of edge-enriched N, S co-doped carbon materials through pyrolysis of thiourea(TU) encapsulated in zeolitic imidazolate frameworks(TU@ZIF) composites,which delivered very good oxygen reduction reaction(ORR) performance in alkaline medium with onset potential of 0.94 V vs. reversible hydrogen electrode(RHE), good stability and methanol tolerance. Density functional theory(DFT) calculations suggested that carbon atoms adjacent to N and S are probable active sites for ORR intermediates in edge-enriched N, S co-doped carbon materials because higher electron density can enhance O_(2)adsorption, lower formation barriers of intermediates, improving the ORR performance comparing to intact N, S co-doped carbon materials. This study might provide a new pathway for improving ORR activity by the integration engineering of edge sites, and electronic structure of heteroatom doped carbon electrocatalysts.展开更多
Dear Editor,Omicron(B.1.1.529)was designated a variant of concern(VOC)on November 26,2021(Callaway,2021),and its subvariants BA.1,BA.2,and BA.3 emerged and circulated almost simultaneously(Desingu et al.,2022).BA.2 wa...Dear Editor,Omicron(B.1.1.529)was designated a variant of concern(VOC)on November 26,2021(Callaway,2021),and its subvariants BA.1,BA.2,and BA.3 emerged and circulated almost simultaneously(Desingu et al.,2022).BA.2 was more efficient in transmission and quickly overtook BA.1 to become the variant most frequently detected worldwide(Yamasoba et al.,2022a).Compared to the prototype SARS-CoV-2 spike protein(S),the BA.1 and BA.2 spike proteins harbor more than 30 mutations,of which 21 are identical between the two subvariants,while the BA.3 spike differs from BA.1 and BA.2 by 3 mutations in the receptor binding domain(RBD)(Fig.1A).More recently,BA.4 and BA.5(hereafter BA.4/5)emerged,sharing the same spike sequence and containing four additional mutations,Del69–70,L452R,F486V,and R493Q,compared with BA.2.BA.4/5 were detected first in South Africa and evolved independently of BA.2;they have spread widely and replaced BA.2 as the predominant VOC(Gruell et al.,2022b;Tegally et al.,2022).In addition,BA.2.75,derived from the BA.2 subvariant,harbors nine additional mutations in the spike protein compared with BA.2(Fig.1A).BA.4/5 and BA.2.75 have led to the continuous emergence of novel Omicron subvariants,including BF.7 and BQ.1.These new subvariants may be driving waves of pandemics.展开更多
Electrochemical conversion of carbon dioxide into fuel and chemicals with added value represents an appealing approach to reduce the greenhouse effect and realize a carbon-neutral cycle,which has great potential in mi...Electrochemical conversion of carbon dioxide into fuel and chemicals with added value represents an appealing approach to reduce the greenhouse effect and realize a carbon-neutral cycle,which has great potential in mitigating global warming and effectively storing renewable energy.The electrochemical CO_(2) reduction reaction(CO_(2)RR)usually involves multiproton coupling and multielectron transfer in aqueous electrolytes to form multicarbon products(C_(2+) products),but it competes with the hydrogen evolution reaction(HER),which results in intrinsically sluggish kinetics and a complex reaction mechanism and places higher requirements on the design of catalysts.In this review,the advantages of electrochemical CO_(2) reduction are briefly introduced,and then,different categories of Cu-based catalysts,including monometallic Cu catalysts,bimetallic catalysts,metal-organic frameworks(MOFs)along with MOF-derived catalysts and other catalysts,are summarized in terms of their synthesis method and conversion of CO_(2) to C2+products in aqueous solution.The catalytic mechanisms of these catalysts are subsequently discussed for rational design of more efficient catalysts.In response to the mechanisms,several material strategies to enhance the catalytic behaviors are proposed,including surface facet engineering,interface engineering,utilization of strong metal-support interactions and surface modification.Based on the above strategies,challenges and prospects are proposed for the future development of CO_(2)RR catalysts for industrial applications.展开更多
Long-term humoral immunity to SARS-CoV-2 is essential for preventing reinfection. The production of neutralizing antibody (nAb)and B cell differentiation are tightly regulated by T follicular help (T_(FH)) cells. Howe...Long-term humoral immunity to SARS-CoV-2 is essential for preventing reinfection. The production of neutralizing antibody (nAb)and B cell differentiation are tightly regulated by T follicular help (T_(FH)) cells. However, the longevity and functional role of T_(FH) cellsubsets in COVID-19 convalescents and vaccine recipients remain poorly defined. Here, we show that SARS-CoV-2 infection andinactivated vaccine elicited both spike-specific CXCR3^(+) T_(FH) cell and CXCR3^(-) T_(FH) cell responses, which showed distinct responsepatterns. Spike- specific CXCR3^(+) T_(FH) cells exhibit a dominant and more durable response than CXCR3^(-) T_(FH) cells that positivelycorrelated with antibody responses. A third booster dose preferentially expands the spike-specific CXCR3^(+) T_(FH) cell subset inducedby two doses of inactivated vaccine, contributing to antibody maturation and potency. Functionally, spike-specific CXCR3^(+) T_(FH) cellshave a greater ability to induce spike-specific antibody secreting cells (ASCs) differentiation compared to spike-specific CXCR3^(-) T_(FH)cells. In conclusion, the persistent and functional role of spike-specific CXCR3^(+) T_(FH) cells following SARS-CoV-2 infection andvaccination may play an important role in antibody maintenance and recall response, thereby conferring long-term protection. Thefindings from this study will inform the development of SARS-CoV-2 vaccines aiming to induce long-term protective immunememory.展开更多
Fe-Mn binary oxide incorporated into porous diatomite(FMBO-diatomite)was prepared in situ and regenerated in a fixed-bed column for arsenite[As(III)]and arsenate[As(V)]removal.Four consecutive adsorption cycles were o...Fe-Mn binary oxide incorporated into porous diatomite(FMBO-diatomite)was prepared in situ and regenerated in a fixed-bed column for arsenite[As(III)]and arsenate[As(V)]removal.Four consecutive adsorption cycles were operated under the following conditions:Initial arsenic concentration of 0.1 mg·L^(-1),empty bed contact time of 5 min,and pH 7.0.About 3000,3300,3800,and 4500 bed volumes of eligible effluent(arsenic concentration≤0.01 mg·L^(-1))were obtained in four As(III)adsorption cycles;while about 2000,2300,2500,and 3100 bed volumes of eligible effluent were obtained in four As(V)adsorption cycles.The dissection results of FMBOdiatomite fixed-bed exhibited that small amounts of manganese and iron were transferred from the top of the fixed-bed to the bottom of the fixed-bed during As(III)removal process.Compared to the extremely low concentration of iron(<0.01 mg·L^(-1)),the fluctuation concentration of Mn2+in effluent of the As(III)removal column was in a range of 0.01-0.08 mg·L^(-1).The release of manganese suggested that manganese oxides played an important role in As(III)oxidation.Determined with the US EPA toxicity characteristic leaching procedure(TCLP),the leaching risk of As(III)on exhausted FMBO-diatomite was lower than that of As(V).展开更多
The ability to adjust the composition and surface structure of Cu-based nanomaterials is important for designing catalysts to effectively convert CO_(2) into multi-carbon products via electrocatalytic reduction.Herein...The ability to adjust the composition and surface structure of Cu-based nanomaterials is important for designing catalysts to effectively convert CO_(2) into multi-carbon products via electrocatalytic reduction.Herein we report a potential-driven in situ forming Cu/Cu_(2)O catalyst featuring interface and tensile strain characteristics from the partial reduction of Cu_(2)O nanocubes for electrocatalytic enhancement of the electrochemical CO_(2) reduction reaction(CO_(2)RR).The results revealed interesting catalytic relationships between Cu^(+)–Cu^(0) compositions and tensile strain,exhibiting maximum faradaic efficiencies for C2 products in the H-type cell at a Cu^(0):Cu^(+)ratio of∼46:54.As revealed by operando X-ray diffraction analysis,Cu/Cu_(2)O in this ratio exhibits a clear tensile strain in Cu during the CO_(2)RR.The outstanding performance of this composition is attributed to the tensile strain and interface of the surface,in addition to the composition synergy due to the Cu^(0) sites decorating the surface in an electron-rich state and being conducive to CO_(2) adsorption and activation and the Cu^(+) sites enhancing the carbon–carbon coupling to adsorbed ^(*)CO,which were also supported by density functional theory(DFT)calculations and in situ ATR-FTIR.The findings open up a new pathway for the rational design of Cu-based catalysts with enhanced activity and selectivity to boost the CO_(2)RR.展开更多
Electrocatalytic CO_(2) reduction reactions(CO_(2)RRs),an efficient method of converting carbon dioxide into valuable fuels and chemicals,are attractive as well as challenging.In this work,Cu_(2)O nanostructures with ...Electrocatalytic CO_(2) reduction reactions(CO_(2)RRs),an efficient method of converting carbon dioxide into valuable fuels and chemicals,are attractive as well as challenging.In this work,Cu_(2)O nanostructures with active facets(face-raised cubic structures(F-Cu_(2)O)with the(100)facet,octahedral structures(O-Cu_(2)O)with the(111)facet and edge-and corner-truncated octahedral structures(T-Cu_(2)O)with both the(100)and(111)facets)were synthesized by a wet chemical reduction method.The surface of Cu_(2)O nanostructures was reconstructed in situ to form Cu_(2)O/Cu with a highly active interface during the conversion of CO_(2) into C_(2)H_(4),which is named F-Cu_(2)O/Cu,O-Cu_(2)O/Cu and T-Cu_(2)O/Cu.The C_(2)H_(4) selectivity on Cu_(2)O/Cu catalysts follows the order of O-Cu_(2)O/Cu<F-Cu_(2)O/Cu<T-Cu_(2)O/Cu,and the faradaic efficiencies of C_(2)H_(4) are 11.2%,24.9%,and 58.0% at -1.1 V versus the reversible hydrogen electrode,respectively.The experimental results combined with operando surface-enhanced Raman spectroscopy reveal that the Cu_(2)O/Cu interface enhances *CO adsorption and decreases the activation energy of C-C coupling,which is also supported by density functional theory(DFT)calculations.This study will pave a feasible pathway for electrochemical energy storage and convention by crystal facet engineering and interface engineering.展开更多
The ability to manipulate Pt-based alloy catalysts with controllable compositions and the type of surface facet is important for advancing direct alcohol fuel cells(DAFEs).Pt_(x)Pd_(100−x) alloy nanowires(NWs)with tun...The ability to manipulate Pt-based alloy catalysts with controllable compositions and the type of surface facet is important for advancing direct alcohol fuel cells(DAFEs).Pt_(x)Pd_(100−x) alloy nanowires(NWs)with tunable compositions and(111)facets show a Boerdijk–Coxeter helix type morphology and a slightly strained lattice,and were synthesized by a single-phase and surfactant-free method.X-ray diffraction results show that the alloy compositions can be used to tune the shrinking or expanding lattice parameter of Pt_(x)Pd_(100−x) NWs.XPS analysis reveals that the alloy effect induced by d-band electron modulation changes the electronic structure and weakens the chemisorption strength of Pt by poisoning species and originally enhances the catalytic activity.The result that the electrocatalytic performance of Pt_(x)Pd_(100−x) NWs for methanol and ethanol oxidation reactions reveals the high catalytic activity correlated with the exposed facet,strained lattice and alloy compositions.The dominant(111)facets of Pt_(62)Pd_(38) NWs show the maximum catalytic activity,which is consistent with the XPS result.This finding will open a new way to design highly active and stable alloy nanocatalysts with controllable compositions for enhancing direct alcohol fuel cells.展开更多
The electrocatalytic activity of nanoalloy catalysts could be effectively manipulated by tuning their intrinsic physical and chemical properties(e.g.,compositions,facets,lattice strain,morphologies,etc.).However,it st...The electrocatalytic activity of nanoalloy catalysts could be effectively manipulated by tuning their intrinsic physical and chemical properties(e.g.,compositions,facets,lattice strain,morphologies,etc.).However,it still remains a challenge how to integrate these beneficial physical and chemical properties to promote the electrocatalytic performances for anode and cathode reactions in fuel cells.Herein,highly catalytic Pt_(n)Cu_(100−n)catalysts with many active sites were synthesized through optimizing the compositions of precursors and reaction conditions and a surfactant-free thermal solvent method,which showed a subtle lattice strain.Transmission electron microscopy and X-ray diffraction results revealed that the lattice strain of Pt_(n)Cu_(100−n)alloy nanostellates could be modulated by the alloy compositions.Electrochemical results showed that the high catalytic activity of Pt_(n)Cu_(100−n)alloy nanostellate catalysts for both the oxygen reduction and alcohol oxidation reactions was related to lattice shrinkage,facets and bimetallic compositions.Interestingly,Pt_(69)Cu_(31)/C nanostellate catalysts with lattice shrinking revealed the maximum activity and stability compared with other compositions and commercial Pt/C,which was also supported by DFT results.This study will provide a new path for the design of robust and active nanoalloy catalysts with lattice mismatch and dominant active facets for both the cathode and anode reactions in fuel cells.展开更多
基金supported by the National Natural Science Foundation of China (No.50608067)the Foundation for Creative Research Groups of China (No.50621804)
文摘A treatment unit packed by granular adsorbent of Fe-Mn binary oxide incorporated into diatomite （FMBO（1：1）-diatomite） was studied to remove arsenic from anaerobic groundwater without any pre-treatment or post-treatment. The raw anaerobic groundwater containing 35-45 μg/L of arsenic was collected from suburb of Beijing. Arsenic（Ⅲ） constituted roughly 60%-80% of the total arsenic content. Approximately 7,000 bed volumes （ratio of effluent volume to adsorbent volume） treated water with arsenic concentration below 10 μg/L were produced in the operation period of four months. The regeneration of FMBO（1：1）-diatomite had been operated for 15 times. In the first stage, the regeneration process significantly improved the adsorption capacity of FMBO（1：1 ）-diatomite. With increased loading amount of Fe-Mn binary oxide, the adsorption capacity for arsenic decreased 20%-40%. Iron and manganese in anaerobic groundwater were oxidized and adsorptive filtrated by FMBO（1 ： 1）-diatomite efficiently. The final concentrations of iron and manganese in effluents were nearly zero. The continued safe performance of the treatment units proved that adsorbent FMBO（1：1）- diatomite had high oxidation ability and exhibited strong adsorptive filtration.
基金supported by the National Natural Science Foundation of China(201573136,21603128,U1510105)the Natural Science Foundation for Young Scientists of Shanxi Province(2016021034)the Scientific Research Start-up Funds of Shanxi University(RSC723)~~
文摘A rational integration of multiple reactive centers into a combined unit to facilitate their cooperative effects is a smart approach for accelerating the catalytic activity.Here,to achieve this goal,linear imidazolium-based ionic polymers were confined into the nanopores of mesoporous silica nanospheres anchored with homogeneously distributed zinc salts.Owing to the flexible character and the reinforced cooperative effects of the ionic liquid(nucleophile)and zinc species(Lewis acid)in the confined mesoporous structure,the resultant composite exhibited dramatically improved catalytic performance in the cycloaddition of CO2 with epoxides to form cyclic carbonates.This was in contrast to that observed for the individual catalytic components.Moreover,such a solid catalyst could be easily recovered and reused four times without a significant loss of activity.
基金Key Specialized Research and Development-International Science and Technology Cooperation Program in Henan Province,Grant/Award Number:231111520500Program for Science&Technology Innovation Talents in Universities of Henan Province,Grant/Award Number:24HASTIT009+2 种基金The 111 Project,Grant/Award Number:D17007National Natural Science Foundation of China,Grant/Award Numbers:52072114,52271176Henan Center for Outstanding Overseas Scientists,Grant/Award Number:GZS2022017。
文摘Electrochemical CO_(2) reduction reaction(CO_(2)RR)offers a promising strategy for CO_(2) conversion into value-added C2+products and facilitates the storage of renewable resources under comparatively mild conditions,but still remains a challenge.Herein,we propose the strategy of surface reconstruction and interface integration engineering to construct tuneable Cu^(0)-Cu^(+)-Cu^(2+)sites and oxygen vacancy oxide derived from CeO_(2)/CuO nanosheets(OD-CeO_(2)/CuO NSs)heterojunction catalysts and promote the activity and selectivity of CO_(2)RR.The optimized OD-CeO_(2)/CuO electrocatalyst shows the maximum Faradic efficiencies for C2+products in the H-type cell,which reaches 69.8%at−1.25 V versus a reversible hydrogen electrode(RHE).Advanced characterization analysis and density functional theory(DFT)calculations further confirm the fact that the existence of oxygen vacancies and Cu^(0)-Cu^(+)-Cu^(2+)sites modified with CeO_(2) is conducive to CO_(2) adsorption and activation,enhances the hydrogenation of^(*)CO to^(*)CHO,and further promotes the dimerization of^(*)CHO,thus promoting the selectivity of C2+generation.This facile interface integration and surface reconstruction strategy provides an ideal strategy to guide the design of CO_(2)RR electrocatalysts.
基金supported by the National Natural Science Foundation of China(No.51271074)the Key Project of Hunan provincial Education Department of China(No.15A146)
文摘Pt-Au alloy nanowires have been controllably electrodeposited on microelectrodes by applying an al- ternating current and were used as the electrocatalyst for formic acid oxidation. The frequency and voltage of the alternating current and the electrolyte composition were adjusted to precisely control the mor- phologies, alloying structures and composition. The characteristics of Pt-Au alloy nanowires were analyzed by scanning electron microscopy, X-ray diffraction and transmission electron spectroscopy. Electrocatalytic performance of formic acid oxidation at Pt-Au alloy nanowires electrode was investigated by cyclic voltammetry and chronoamperometry. The results showed that the Pt-Au alloy nanowires possessed highly- crystalline morphologies, the controllable bimetallic composition and single-phase alloy structures, which mainly grow in the 〈111〉 crystal orientation. The electrocatalytic activity of formic acid oxidation strongly depended on the bimetallic Pt/Au composition. The PtjsAu6s alloy nanowires displayed superior electrocatalytic performance and high stability toward the electrooxidation of formic acid in acidic so- lution, owing to the ensemble effect of the Pt and Au components. These findings provided insights into the design of the Pt-Au bimetallic nanomaterials as electrocatalvsts for formic acid oxidation.
基金supported financially by the National Natural Science Foundation of China (No. 21905271)Liaoning Natural Science Foundation (No. 20180510029)the Dalian National Laboratory for Clean Energy (DNL), DNL Cooperation Fund, Chinese Academy of Sciences (No. DNL180402)。
文摘The development of carbon materials with high electrochemical performance for next-generation energy device is emerging, especially N, S co-doped carbon materials have sparked intensive attention. However,the exploration of N, S co-doped carbon with well-defined active sites and hierarchical porous structures are still limited. In this study, we prepared a series of edge-enriched N, S co-doped carbon materials through pyrolysis of thiourea(TU) encapsulated in zeolitic imidazolate frameworks(TU@ZIF) composites,which delivered very good oxygen reduction reaction(ORR) performance in alkaline medium with onset potential of 0.94 V vs. reversible hydrogen electrode(RHE), good stability and methanol tolerance. Density functional theory(DFT) calculations suggested that carbon atoms adjacent to N and S are probable active sites for ORR intermediates in edge-enriched N, S co-doped carbon materials because higher electron density can enhance O_(2)adsorption, lower formation barriers of intermediates, improving the ORR performance comparing to intact N, S co-doped carbon materials. This study might provide a new pathway for improving ORR activity by the integration engineering of edge sites, and electronic structure of heteroatom doped carbon electrocatalysts.
基金supported by the National Natural Science Foundation of China(82061138020,32270996,82102365)The Science and Technology Innovation Program of Hunan Province of China(2022RC3079)+5 种基金the Educational Commission of Hunan Province of China(21A0529)the Natural Science Foundation of Hunan Province of China(2021JJ40006,2022JJ30095)the Clinical Medical Innovation Technology Guide Project of Hunan Province(2021SK50304,2021SK50306 and 2021SK50312)“SC1-PHE-CORONAVIRUS-2020:Advancing knowledge for the clinical and public health response to the 2019-nCoV epidemic”from the European Commission(CORONADX,no.101003562)(to Y-P.L.)approved by the Institutional Ethical Review Board of The Central Hospital of Shaoyang,Hunan Province,China(V.1.0,20200301)The First People's Hospital of Chenzhou,Hunan Province,China(V.3.0,2021001).
文摘Dear Editor,Omicron(B.1.1.529)was designated a variant of concern(VOC)on November 26,2021(Callaway,2021),and its subvariants BA.1,BA.2,and BA.3 emerged and circulated almost simultaneously(Desingu et al.,2022).BA.2 was more efficient in transmission and quickly overtook BA.1 to become the variant most frequently detected worldwide(Yamasoba et al.,2022a).Compared to the prototype SARS-CoV-2 spike protein(S),the BA.1 and BA.2 spike proteins harbor more than 30 mutations,of which 21 are identical between the two subvariants,while the BA.3 spike differs from BA.1 and BA.2 by 3 mutations in the receptor binding domain(RBD)(Fig.1A).More recently,BA.4 and BA.5(hereafter BA.4/5)emerged,sharing the same spike sequence and containing four additional mutations,Del69–70,L452R,F486V,and R493Q,compared with BA.2.BA.4/5 were detected first in South Africa and evolved independently of BA.2;they have spread widely and replaced BA.2 as the predominant VOC(Gruell et al.,2022b;Tegally et al.,2022).In addition,BA.2.75,derived from the BA.2 subvariant,harbors nine additional mutations in the spike protein compared with BA.2(Fig.1A).BA.4/5 and BA.2.75 have led to the continuous emergence of novel Omicron subvariants,including BF.7 and BQ.1.These new subvariants may be driving waves of pandemics.
基金supported by the Higher Education Discipline Innovation Project(Grant No.D17007)Henan Center for Outstanding Overseas Scientists(Grant No.GZS2022017)+2 种基金National Science Foundation of China(Grant Nos.21908045,51922008,52072114 and 51872075)China Postdoctoral Science Foundation(Grant No.2018M642754)Talent Postdoctoral Program for Henan Province(Grant No.ZYQR201810170).
文摘Electrochemical conversion of carbon dioxide into fuel and chemicals with added value represents an appealing approach to reduce the greenhouse effect and realize a carbon-neutral cycle,which has great potential in mitigating global warming and effectively storing renewable energy.The electrochemical CO_(2) reduction reaction(CO_(2)RR)usually involves multiproton coupling and multielectron transfer in aqueous electrolytes to form multicarbon products(C_(2+) products),but it competes with the hydrogen evolution reaction(HER),which results in intrinsically sluggish kinetics and a complex reaction mechanism and places higher requirements on the design of catalysts.In this review,the advantages of electrochemical CO_(2) reduction are briefly introduced,and then,different categories of Cu-based catalysts,including monometallic Cu catalysts,bimetallic catalysts,metal-organic frameworks(MOFs)along with MOF-derived catalysts and other catalysts,are summarized in terms of their synthesis method and conversion of CO_(2) to C2+products in aqueous solution.The catalytic mechanisms of these catalysts are subsequently discussed for rational design of more efficient catalysts.In response to the mechanisms,several material strategies to enhance the catalytic behaviors are proposed,including surface facet engineering,interface engineering,utilization of strong metal-support interactions and surface modification.Based on the above strategies,challenges and prospects are proposed for the future development of CO_(2)RR catalysts for industrial applications.
基金the National Natural Science Foundation of China(92269115,82061138020,32270996,82102365)The Science and Technology Innovation Program of Hunan Province of China(2022RC3079)+5 种基金Natural Science Foundation of Hunan Province of China(2021JJ40006,2022JJ30095)Educational Commission of Hunan Province of China(21A0529)The Clinical Medical Innovation Technology Guide Project of Hunan Province(2021SK50304,2021SK50306 and 2021SK50312)General Project of Health Commission of Hunan Province(B202303087545,D202302076189)SC1-PHE-CORONAVIRUS-2020:"Advancing knowledge for the clinical and public health response to the 2019-nCoV epidemic"from the European Commission(CORONADX,no.101003562)(Y.-P.L)NSF KP-06-DK-3/2(2020),Republic of Bulgaria.
文摘Long-term humoral immunity to SARS-CoV-2 is essential for preventing reinfection. The production of neutralizing antibody (nAb)and B cell differentiation are tightly regulated by T follicular help (T_(FH)) cells. However, the longevity and functional role of T_(FH) cellsubsets in COVID-19 convalescents and vaccine recipients remain poorly defined. Here, we show that SARS-CoV-2 infection andinactivated vaccine elicited both spike-specific CXCR3^(+) T_(FH) cell and CXCR3^(-) T_(FH) cell responses, which showed distinct responsepatterns. Spike- specific CXCR3^(+) T_(FH) cells exhibit a dominant and more durable response than CXCR3^(-) T_(FH) cells that positivelycorrelated with antibody responses. A third booster dose preferentially expands the spike-specific CXCR3^(+) T_(FH) cell subset inducedby two doses of inactivated vaccine, contributing to antibody maturation and potency. Functionally, spike-specific CXCR3^(+) T_(FH) cellshave a greater ability to induce spike-specific antibody secreting cells (ASCs) differentiation compared to spike-specific CXCR3^(-) T_(FH)cells. In conclusion, the persistent and functional role of spike-specific CXCR3^(+) T_(FH) cells following SARS-CoV-2 infection andvaccination may play an important role in antibody maintenance and recall response, thereby conferring long-term protection. Thefindings from this study will inform the development of SARS-CoV-2 vaccines aiming to induce long-term protective immunememory.
基金This research was supported by the National Natural Science Foundation of China(Grant No.50608067)the Funds for Creative Research Groups of China(Grant No.50621804).
文摘Fe-Mn binary oxide incorporated into porous diatomite(FMBO-diatomite)was prepared in situ and regenerated in a fixed-bed column for arsenite[As(III)]and arsenate[As(V)]removal.Four consecutive adsorption cycles were operated under the following conditions:Initial arsenic concentration of 0.1 mg·L^(-1),empty bed contact time of 5 min,and pH 7.0.About 3000,3300,3800,and 4500 bed volumes of eligible effluent(arsenic concentration≤0.01 mg·L^(-1))were obtained in four As(III)adsorption cycles;while about 2000,2300,2500,and 3100 bed volumes of eligible effluent were obtained in four As(V)adsorption cycles.The dissection results of FMBOdiatomite fixed-bed exhibited that small amounts of manganese and iron were transferred from the top of the fixed-bed to the bottom of the fixed-bed during As(III)removal process.Compared to the extremely low concentration of iron(<0.01 mg·L^(-1)),the fluctuation concentration of Mn2+in effluent of the As(III)removal column was in a range of 0.01-0.08 mg·L^(-1).The release of manganese suggested that manganese oxides played an important role in As(III)oxidation.Determined with the US EPA toxicity characteristic leaching procedure(TCLP),the leaching risk of As(III)on exhausted FMBO-diatomite was lower than that of As(V).
基金support the findings of this study are available in the ESI†of this article.
文摘The ability to adjust the composition and surface structure of Cu-based nanomaterials is important for designing catalysts to effectively convert CO_(2) into multi-carbon products via electrocatalytic reduction.Herein we report a potential-driven in situ forming Cu/Cu_(2)O catalyst featuring interface and tensile strain characteristics from the partial reduction of Cu_(2)O nanocubes for electrocatalytic enhancement of the electrochemical CO_(2) reduction reaction(CO_(2)RR).The results revealed interesting catalytic relationships between Cu^(+)–Cu^(0) compositions and tensile strain,exhibiting maximum faradaic efficiencies for C2 products in the H-type cell at a Cu^(0):Cu^(+)ratio of∼46:54.As revealed by operando X-ray diffraction analysis,Cu/Cu_(2)O in this ratio exhibits a clear tensile strain in Cu during the CO_(2)RR.The outstanding performance of this composition is attributed to the tensile strain and interface of the surface,in addition to the composition synergy due to the Cu^(0) sites decorating the surface in an electron-rich state and being conducive to CO_(2) adsorption and activation and the Cu^(+) sites enhancing the carbon–carbon coupling to adsorbed ^(*)CO,which were also supported by density functional theory(DFT)calculations and in situ ATR-FTIR.The findings open up a new pathway for the rational design of Cu-based catalysts with enhanced activity and selectivity to boost the CO_(2)RR.
基金supported by the 111 Project(Grant No.D17007)Henan Center for Outstanding Overseas Scientists(Grant No.GZS2022017)the National Science Foundation of China(Grant No.21908045,52072114,51922008 and 51872075).
文摘Electrocatalytic CO_(2) reduction reactions(CO_(2)RRs),an efficient method of converting carbon dioxide into valuable fuels and chemicals,are attractive as well as challenging.In this work,Cu_(2)O nanostructures with active facets(face-raised cubic structures(F-Cu_(2)O)with the(100)facet,octahedral structures(O-Cu_(2)O)with the(111)facet and edge-and corner-truncated octahedral structures(T-Cu_(2)O)with both the(100)and(111)facets)were synthesized by a wet chemical reduction method.The surface of Cu_(2)O nanostructures was reconstructed in situ to form Cu_(2)O/Cu with a highly active interface during the conversion of CO_(2) into C_(2)H_(4),which is named F-Cu_(2)O/Cu,O-Cu_(2)O/Cu and T-Cu_(2)O/Cu.The C_(2)H_(4) selectivity on Cu_(2)O/Cu catalysts follows the order of O-Cu_(2)O/Cu<F-Cu_(2)O/Cu<T-Cu_(2)O/Cu,and the faradaic efficiencies of C_(2)H_(4) are 11.2%,24.9%,and 58.0% at -1.1 V versus the reversible hydrogen electrode,respectively.The experimental results combined with operando surface-enhanced Raman spectroscopy reveal that the Cu_(2)O/Cu interface enhances *CO adsorption and decreases the activation energy of C-C coupling,which is also supported by density functional theory(DFT)calculations.This study will pave a feasible pathway for electrochemical energy storage and convention by crystal facet engineering and interface engineering.
基金supported by the 111 Project(Grant No.D17007)Henan Center for Outstanding Overseas Scientists(Grant No.GZS2018003)+2 种基金the National Science Foundation of China(Grant No.21908045,51922008 and 51872075)the China Postdoctoral Science Foundation(Grant No.2018M642754)Talent Postdoctoral Program for Henan Province(Grant No.ZYQR201810170).
文摘The ability to manipulate Pt-based alloy catalysts with controllable compositions and the type of surface facet is important for advancing direct alcohol fuel cells(DAFEs).Pt_(x)Pd_(100−x) alloy nanowires(NWs)with tunable compositions and(111)facets show a Boerdijk–Coxeter helix type morphology and a slightly strained lattice,and were synthesized by a single-phase and surfactant-free method.X-ray diffraction results show that the alloy compositions can be used to tune the shrinking or expanding lattice parameter of Pt_(x)Pd_(100−x) NWs.XPS analysis reveals that the alloy effect induced by d-band electron modulation changes the electronic structure and weakens the chemisorption strength of Pt by poisoning species and originally enhances the catalytic activity.The result that the electrocatalytic performance of Pt_(x)Pd_(100−x) NWs for methanol and ethanol oxidation reactions reveals the high catalytic activity correlated with the exposed facet,strained lattice and alloy compositions.The dominant(111)facets of Pt_(62)Pd_(38) NWs show the maximum catalytic activity,which is consistent with the XPS result.This finding will open a new way to design highly active and stable alloy nanocatalysts with controllable compositions for enhancing direct alcohol fuel cells.
基金supported by the 111 Project(Grant No.D17007)Henan Center for Outstanding Overseas Scientists(Grant No.GZS2018003)+2 种基金the National Science Foundation of China(Grant No.21908045,51922008 and 51872075)the China Postdoctoral Science Foundation(Grant No.2018M642754)the Talent postdoctoral program for Henan province(Grant No.ZYQR201810170).
文摘The electrocatalytic activity of nanoalloy catalysts could be effectively manipulated by tuning their intrinsic physical and chemical properties(e.g.,compositions,facets,lattice strain,morphologies,etc.).However,it still remains a challenge how to integrate these beneficial physical and chemical properties to promote the electrocatalytic performances for anode and cathode reactions in fuel cells.Herein,highly catalytic Pt_(n)Cu_(100−n)catalysts with many active sites were synthesized through optimizing the compositions of precursors and reaction conditions and a surfactant-free thermal solvent method,which showed a subtle lattice strain.Transmission electron microscopy and X-ray diffraction results revealed that the lattice strain of Pt_(n)Cu_(100−n)alloy nanostellates could be modulated by the alloy compositions.Electrochemical results showed that the high catalytic activity of Pt_(n)Cu_(100−n)alloy nanostellate catalysts for both the oxygen reduction and alcohol oxidation reactions was related to lattice shrinkage,facets and bimetallic compositions.Interestingly,Pt_(69)Cu_(31)/C nanostellate catalysts with lattice shrinking revealed the maximum activity and stability compared with other compositions and commercial Pt/C,which was also supported by DFT results.This study will provide a new path for the design of robust and active nanoalloy catalysts with lattice mismatch and dominant active facets for both the cathode and anode reactions in fuel cells.
