In recent years,studies focusing on the conversion of renewable lignin-derived oxygenates(LDOs)have emphasized their potential as alternatives to fossil-based products.However,LDOs,existing as complex aromatic mixture...In recent years,studies focusing on the conversion of renewable lignin-derived oxygenates(LDOs)have emphasized their potential as alternatives to fossil-based products.However,LDOs,existing as complex aromatic mixtures with diverse oxygen-containing functional groups,pose a challenge as they cannot be easily separated via distillation for direct utilization.A promising solution to this challenge lies in the efficient removal of oxygen-containing functional groups from LDOs through hydrodeoxygenation(HDO),aiming to yield biomass products with singular components.However,the high dissociation energy of the carbon-oxygen bond,coupled with its similarity to the hydrogenation energy of the benzene ring,creates a competition between deoxygenation and benzene ring hydrogenation.Considering hydrogen consumption and lignin properties,the preference is directed towards generating aromatic hydrocarbons rather than saturated components.Thus,the goal is to selectively remove oxygen-containing functional groups while preserving the benzene ring structure.Studies on LDOs conversion have indicated that the design of active components and optimization of reaction conditions play pivotal roles in achieving selective deoxygenation,but a summary of the correlation between these factors and the reaction mechanism is lacking.This review addresses this gap in knowledge by firstly summarizing the various reaction pathways for HDO of LDOs.It explores the impact of catalyst design strategies,including morphology modulation,elemental doping,and surface modification,on the adsorption-desorption dynamics between reactants and catalysts.Secondly,we delve into the application of advanced techniques such as spectroscopic techniques and computational modeling,aiding in uncovering the true active sites in HDO reactions and understanding the interaction of reactive reactants with catalyst surface-interfaces.Additionally,fundamental insights into selective deoxygenation obtained through these techniques are highlighted.Finally,we outline the challenges that lie ahead in the design of highly active and selective HDO catalysts.These challenges include the development of detection tools for reactive species with high activity at low concentrations,the study of reaction medium-catalyst interactions,and the development of theoretical models that more closely approximate real reaction situations.Addressing these challenges will pave the way for the development of efficient and selective HDO catalysts,thus advancing the field of renewable LDOs conversion.展开更多
Zn-air battery(ZAB)has garnered significant attention owing to its environmental friendliness and safety attributes.A critical challenge in advancing ZAB technology lies in the development of high-performance and cost...Zn-air battery(ZAB)has garnered significant attention owing to its environmental friendliness and safety attributes.A critical challenge in advancing ZAB technology lies in the development of high-performance and cost-effective electrocatalysts for oxygen redox reactions(OER and ORR).Herein,we report Co/Fe carbon-supported composites as efficient bifunctional catalyst encapsulated in oxidative ammonolysis modified lignin-derived N-doped biochar(Co Fe-Co_(x)N@NOALC).It exhibited exceptional electrochemical performance in aqueous ZAB owing to their uniform dispersed and small particle size,with a peak power density of 154 mW/cm^(2)and a specific capacity of 770 mAh/g.Most notably,it exhibited a long cycle stability,surpassing 1500 h at a current density of 10 mA/cm^(2),with a mere 11.4%decrease in the chargedischarge efficiency of the battery.This study proposes a viable strategy for enhancing the performance and reducing the cost of Zn-air batteries through the utilization of biomass-derived materials.展开更多
Molybdenum nickel alloy has been proved to be an efficient noble-metal-free catalyst for hydrogen evolution reaction(HER) in alkaline medium, but its electrocatalytic activity and stability need to be further improved...Molybdenum nickel alloy has been proved to be an efficient noble-metal-free catalyst for hydrogen evolution reaction(HER) in alkaline medium, but its electrocatalytic activity and stability need to be further improved to meet industrial requirements. In this study, carboxymethylated enzymatic hydrolysis lignin(EHL) was used as a biomacromolecule frame to coordinate with transition metal ions and reduced by pyrolysis to obtain the MoNi_(4)-NiO heterojunction(MoNi_(4)-NiO/C). The oblate sphere structure of MoNi_(4)-NiO/C exposed a large catalytic active surface to the electrolyte. As a result, the hydrogen evolution reaction of MoNi_(4)-NiO/C displayed a low overpotentials of 41 mV to achieve 10 mA cm-2and excellent stability of 100 h at 100 mA cm^(-2)in 1 mol L^(-1)KOH, which was superior to that of commercial Pt/C. Lignin assisted the formation of NiO to construct the MoNi_(4)-NiO interface and MoNi_(4)-NiO heterojunction structure, which reduced the energy barrier by forming a more favorable transition states and then promoted the formation of adsorbed hydrogen at the heterojunction interface through water dissociation in alkaline media, leading to the rapid reaction kinetics. This work provided an effective strategy for improving the electrocatalytic performance of noble-metal-free electrocatalysts encapsulated by lignin-derived carbon.展开更多
Design of a robust catalyst with high activity but the low cost for the hydrodeoxygenation(HDO) of biooils is of great importance to bring the biorefinery concept into reality.In this study,density functional theory(D...Design of a robust catalyst with high activity but the low cost for the hydrodeoxygenation(HDO) of biooils is of great importance to bring the biorefinery concept into reality.In this study,density functional theory(DFT) calculation was adopted to analyze the optimal location of Ni on MoO_(3-x) containing oxygen vacancy,and the corresponding result demonstrated that metallic Ni cluster located at the neighborhood of oxygen vacancies would significantly evoke HDO activity.Enlightened by DFT results,NiMoO_(4) was first hydrothermally synthesized and then employed to fabricate Ni-MoO_(3-x) catalyst via a low-temperature reduction,where Ni escaped from NiMoO_(4) and was reduced to its metallic state.Such an evolution of Ni species also induced the formation of oxygen vacancies around metallic Ni cluster.In the HDO of p-cresol,Ni-MoO_(3-x) exhibited high activity with a complete conversion and a methylcyclohexane selectivity of 99.4% at 150℃.Moreover,the catalyst showed good versatility in catalyzing HDO of diverse lignin-derived oxygenates and lignin oil.2D HSQC NMR,gas chromatograph and elemental analysis of the lignin oil demonstrated the high deoxygenation efficiency and saturation of the benzene ring over Ni-MoO_(3-x).In the upgrading of crude lignin oil,the deoxygenation degree was up to 99%,and the overall carbon yield of the naphthenes was as high as 69.4%.Importantly,the structures and carbon numbers of the naphthene products are similar to jet fuel-range cycloalka nes,which are expected to have a high density that can be blended into jet fuel to raise the range(or payload) of airplanes.This work demonstrates the feasibility for improving the targeted catalytic reactivity by rational tailoring the catalyst structure under the guidance of theoretical analysis,and provides an energy-efficient route for the upgrading of lignin crude oil into valuable naphthenes.展开更多
Lignin degradation is a major process in the global carbon cycle across both terrestrial and marine ecosystems.Bathyarchaeia,which are among the most abundant microorganisms in marine sediment,have been proposed to me...Lignin degradation is a major process in the global carbon cycle across both terrestrial and marine ecosystems.Bathyarchaeia,which are among the most abundant microorganisms in marine sediment,have been proposed to mediate anaerobic lignin degradation.However,the mechanism of bathyarchaeial lignin degradation remains unclear.Here,we report an enrichment culture of Bathy-archaeia,named Candidatus Baizosediminiarchaeum ligniniphilus DL1YTT001(Ca.B.ligniniphilus),from coastal sediments that can grow with lignin as the sole organic carbon source under mesophilic anoxic conditions.Ca.B.ligniniphilus possesses and highly expresses novel methyltransferase 1(MT1,mtgB)for transferring methoxyl groups from lignin monomers to cob(I)alamin.MtgBs have no homology with known microbial methyltransferases and are present only in bathyarchaeial lineages.Heterologous expression of the mtgB gene confirmed O-demethylation activity.The mtgB genes were identified in metagenomic data sets from a wide range of coastal sediments,and they were highly expressed in coastal sediments from the East China Sea.These findings suggest that Bathyarchaeia,capable of O-demethylation via their novel and specific methyltransferases,are ubiquitous in coastal sediments.展开更多
SAPO-5 zeolite supported RuMn was a highly efficient catalyst for the aqueous-phase selective hydrodeoxygenation of guaiacol to cyclohexanol.The optimal catalyst achieved a high cyclohexanol yield of 93.7%at full guai...SAPO-5 zeolite supported RuMn was a highly efficient catalyst for the aqueous-phase selective hydrodeoxygenation of guaiacol to cyclohexanol.The optimal catalyst achieved a high cyclohexanol yield of 93.7%at full guaiacol conversion under mild conditions,with a high TOF of 920 h^(-1).Moreover,the catalyst displayed remarkable performance for the hydrogenation of phenol to cyclohexanol,where a 100%yield of cyclohexanol was obtained at a phenol-to-Ru molar ratio of about 17900.In particular,the catalyst exhibited excellent recyclability and could be recycled for 20 times without obvious activity loss.The as-prepared RuMn/SAPO-5 catalyst exhibited higher performance than most of the reported Rubased catalysts.展开更多
Lignin-derived hard carbon shows potential as an anode material for sodium-ion batteries(SIBs)due to its high carbon content and aromatic structure,but its limited reversible adsorption sites and low conductivity hind...Lignin-derived hard carbon shows potential as an anode material for sodium-ion batteries(SIBs)due to its high carbon content and aromatic structure,but its limited reversible adsorption sites and low conductivity hinder performance.This study introduces a self-activation strategy to optimize carbon layer stacking and surface functional groups in microporous carbon,significantly enhancing sodium storage capacity and rate performance.By utilizing oxygen-containing functional groups in organic solvent lignin,we induce micropore formation during pyrolysis,effectively regulating graphite domains and closed pores structures without disrupting carbon layer growth.Unstacked graphene layers serve as efficient electron transport channels and expose additional adsorption sites,simultaneously increasing sodium storage capacity and intrinsic conductivity.The resultant S-OLHC demonstrates a remarkable sodium storage capacity of 358 mA h/g at 0.05 A/g after 200 cycles and maintains 231 mA h/g after 1000 cycles at 2 A/g.This strategy eliminates the need for additional pore-forming agents,offering a simpler,more efficient,and environmentally friendly approach compared to traditional activation methods.This work advances the rational design of high-performance biomass-derived hard carbon for SIBs by leveraging inherent structural characteristics and provides a sustainable low-carbon strategy for lignin valorization in renewable energy storage.展开更多
Nowadays,hierarchically macro-/meso-/microporous 3D carbon materials have been paid more attention due to their imaginative application potential in specific electrochemistry.Here,we report a dualtemplate strategy usi...Nowadays,hierarchically macro-/meso-/microporous 3D carbon materials have been paid more attention due to their imaginative application potential in specific electrochemistry.Here,we report a dualtemplate strategy using eutectic NaCl/ZnCl2 melt as airtight and swelling agent to obtain 3D mesoporous skeleton structured carbon from renewable lignin.The prepared lignin-derived biocarbon material(LN-3-1)has a high specific surface area(1289 m^2 g^-1),a large pore volume(2.80 cm^3 g^-1),and a well-connected and stable structure.LN-3-1 exhibits extremely high activity and stability in acidic medium for oxygen reduction reaction(ORR),superior to Pt/C catalyst and most non noble-metal catalysts reported in recent literatures.The prepared carbon material was used as a cathode catalyst to assemble a H2-O2 single fuel cell,and its excellent catalytic performance has been confirmed with the maximum power density of 779 mW cm^-2,which is one of the highest power densities among non-metallic catalysts so far.Density functional theory(DFT)calculations indicate that the synergy of chlorine and nitrogen reconciles the intermediate adsorption energies,leading to an appropriate theoretical ORR onset potential.We develop a cost-effective and highly efficient method to prepare biocarbon catalyst for ORR in proton-exchange membrane fuel cells.展开更多
In this study, lignin-derived phenols were used to determine the sources and distribution of sedimentary organic matter along the northern Bering Sea and Chukchi Sea of the Arctic Ocean. The lignin parameter syringyl/...In this study, lignin-derived phenols were used to determine the sources and distribution of sedimentary organic matter along the northern Bering Sea and Chukchi Sea of the Arctic Ocean. The lignin parameter syringyl/vanillyl（S/V） and cinnamyl/vanillyl（C/V） ratios are used to indicate vegetation sources; and the ratios of vanillic acid/vanillin,（Ad/Al）v and syringic acid/syringaldehyde,（Ad/Al）s are used as indicators of lignin diagenesis. Results showed the predominance of woody gymnosperm signal at the easternmost location in the northern Bering Sea, a mixture of refractory non-woody angiosperm and fresher gymnosperm tissues in the Chukchi Sea, and signal of fresher woody gymnosperm tissues in the northernmost locations in the Chukchi Sea. The lignin materials showed gradual increase in decomposition stage during transport along the northern Bering Sea. Hydrodynamic sorting process, which is the retention of coarser materials nearshore and transportation of finer particles farther offshore, most probably occurred along the east coast of the northern Bering Sea. In Chukchi Sea, the non-woody angiosperm tissues could have originated from the Canadian Arctic and gymnosperm tissues could be from the Russian Arctic side. The fresher materials in the northernmost Chukchi Sea could have been transported here via the ice-rafting process.Detection of fresh lignin materials and the occurrence of lignin decomposition mean that this region could be sensitive to the impact of climate change.展开更多
基金supported by the National Natural Science Foundation of China,Pilot Group Program of the Research Fund for International Senior Scientists(22250710676)National Natural Science Foundation of China(22078064,22378062,22304028)+1 种基金Natural Science Foundation of Fujian Province(2021J02009)Tianjin University-Fuzhou University Independent Innovation Fund Cooperation Project(TF2023-1,TF2023-8).
文摘In recent years,studies focusing on the conversion of renewable lignin-derived oxygenates(LDOs)have emphasized their potential as alternatives to fossil-based products.However,LDOs,existing as complex aromatic mixtures with diverse oxygen-containing functional groups,pose a challenge as they cannot be easily separated via distillation for direct utilization.A promising solution to this challenge lies in the efficient removal of oxygen-containing functional groups from LDOs through hydrodeoxygenation(HDO),aiming to yield biomass products with singular components.However,the high dissociation energy of the carbon-oxygen bond,coupled with its similarity to the hydrogenation energy of the benzene ring,creates a competition between deoxygenation and benzene ring hydrogenation.Considering hydrogen consumption and lignin properties,the preference is directed towards generating aromatic hydrocarbons rather than saturated components.Thus,the goal is to selectively remove oxygen-containing functional groups while preserving the benzene ring structure.Studies on LDOs conversion have indicated that the design of active components and optimization of reaction conditions play pivotal roles in achieving selective deoxygenation,but a summary of the correlation between these factors and the reaction mechanism is lacking.This review addresses this gap in knowledge by firstly summarizing the various reaction pathways for HDO of LDOs.It explores the impact of catalyst design strategies,including morphology modulation,elemental doping,and surface modification,on the adsorption-desorption dynamics between reactants and catalysts.Secondly,we delve into the application of advanced techniques such as spectroscopic techniques and computational modeling,aiding in uncovering the true active sites in HDO reactions and understanding the interaction of reactive reactants with catalyst surface-interfaces.Additionally,fundamental insights into selective deoxygenation obtained through these techniques are highlighted.Finally,we outline the challenges that lie ahead in the design of highly active and selective HDO catalysts.These challenges include the development of detection tools for reactive species with high activity at low concentrations,the study of reaction medium-catalyst interactions,and the development of theoretical models that more closely approximate real reaction situations.Addressing these challenges will pave the way for the development of efficient and selective HDO catalysts,thus advancing the field of renewable LDOs conversion.
基金sponsored by the National Natural Science Foundation of China(Nos.U23A6005 and 22178069)。
文摘Zn-air battery(ZAB)has garnered significant attention owing to its environmental friendliness and safety attributes.A critical challenge in advancing ZAB technology lies in the development of high-performance and cost-effective electrocatalysts for oxygen redox reactions(OER and ORR).Herein,we report Co/Fe carbon-supported composites as efficient bifunctional catalyst encapsulated in oxidative ammonolysis modified lignin-derived N-doped biochar(Co Fe-Co_(x)N@NOALC).It exhibited exceptional electrochemical performance in aqueous ZAB owing to their uniform dispersed and small particle size,with a peak power density of 154 mW/cm^(2)and a specific capacity of 770 mAh/g.Most notably,it exhibited a long cycle stability,surpassing 1500 h at a current density of 10 mA/cm^(2),with a mere 11.4%decrease in the chargedischarge efficiency of the battery.This study proposes a viable strategy for enhancing the performance and reducing the cost of Zn-air batteries through the utilization of biomass-derived materials.
基金the financial support of the National Natural Science Foundation of China (22038004, 22078069 and 22178069)the Guangdong Basic and Applied Basic Research Foundation (2019B151502038 and 2021A1515012354)+1 种基金Guangdong Provincial Key Research and Development Program (2020B1111380002)the Guangdong Provincial Key Laboratory of Plant Resources Biorefinery (2021GDKLPRB-K05)。
文摘Molybdenum nickel alloy has been proved to be an efficient noble-metal-free catalyst for hydrogen evolution reaction(HER) in alkaline medium, but its electrocatalytic activity and stability need to be further improved to meet industrial requirements. In this study, carboxymethylated enzymatic hydrolysis lignin(EHL) was used as a biomacromolecule frame to coordinate with transition metal ions and reduced by pyrolysis to obtain the MoNi_(4)-NiO heterojunction(MoNi_(4)-NiO/C). The oblate sphere structure of MoNi_(4)-NiO/C exposed a large catalytic active surface to the electrolyte. As a result, the hydrogen evolution reaction of MoNi_(4)-NiO/C displayed a low overpotentials of 41 mV to achieve 10 mA cm-2and excellent stability of 100 h at 100 mA cm^(-2)in 1 mol L^(-1)KOH, which was superior to that of commercial Pt/C. Lignin assisted the formation of NiO to construct the MoNi_(4)-NiO interface and MoNi_(4)-NiO heterojunction structure, which reduced the energy barrier by forming a more favorable transition states and then promoted the formation of adsorbed hydrogen at the heterojunction interface through water dissociation in alkaline media, leading to the rapid reaction kinetics. This work provided an effective strategy for improving the electrocatalytic performance of noble-metal-free electrocatalysts encapsulated by lignin-derived carbon.
基金supported by the National Key R&D Program of China (2022YFB3805401, 2019YFC1905300)the National Natural Science Foundation of China (22178297)+1 种基金the Hunan Provincial Natural Science Foundation (2022JJ40425, 2022JJ40432)the Process Intensification and Green Chemical Engineering Innovation Team of Hunan Province。
文摘Design of a robust catalyst with high activity but the low cost for the hydrodeoxygenation(HDO) of biooils is of great importance to bring the biorefinery concept into reality.In this study,density functional theory(DFT) calculation was adopted to analyze the optimal location of Ni on MoO_(3-x) containing oxygen vacancy,and the corresponding result demonstrated that metallic Ni cluster located at the neighborhood of oxygen vacancies would significantly evoke HDO activity.Enlightened by DFT results,NiMoO_(4) was first hydrothermally synthesized and then employed to fabricate Ni-MoO_(3-x) catalyst via a low-temperature reduction,where Ni escaped from NiMoO_(4) and was reduced to its metallic state.Such an evolution of Ni species also induced the formation of oxygen vacancies around metallic Ni cluster.In the HDO of p-cresol,Ni-MoO_(3-x) exhibited high activity with a complete conversion and a methylcyclohexane selectivity of 99.4% at 150℃.Moreover,the catalyst showed good versatility in catalyzing HDO of diverse lignin-derived oxygenates and lignin oil.2D HSQC NMR,gas chromatograph and elemental analysis of the lignin oil demonstrated the high deoxygenation efficiency and saturation of the benzene ring over Ni-MoO_(3-x).In the upgrading of crude lignin oil,the deoxygenation degree was up to 99%,and the overall carbon yield of the naphthenes was as high as 69.4%.Importantly,the structures and carbon numbers of the naphthene products are similar to jet fuel-range cycloalka nes,which are expected to have a high density that can be blended into jet fuel to raise the range(or payload) of airplanes.This work demonstrates the feasibility for improving the targeted catalytic reactivity by rational tailoring the catalyst structure under the guidance of theoretical analysis,and provides an energy-efficient route for the upgrading of lignin crude oil into valuable naphthenes.
基金supported financially by the Natural Science Foundation of China(Grants 42276139,42230401,42141003,41921006,92051116,91951209)2030 Project,Shanghai Jiao Tong University(Grant WH510244001)the National Postdoctoral Program for Innovative Talents(Grant No.BX20190204).
文摘Lignin degradation is a major process in the global carbon cycle across both terrestrial and marine ecosystems.Bathyarchaeia,which are among the most abundant microorganisms in marine sediment,have been proposed to mediate anaerobic lignin degradation.However,the mechanism of bathyarchaeial lignin degradation remains unclear.Here,we report an enrichment culture of Bathy-archaeia,named Candidatus Baizosediminiarchaeum ligniniphilus DL1YTT001(Ca.B.ligniniphilus),from coastal sediments that can grow with lignin as the sole organic carbon source under mesophilic anoxic conditions.Ca.B.ligniniphilus possesses and highly expresses novel methyltransferase 1(MT1,mtgB)for transferring methoxyl groups from lignin monomers to cob(I)alamin.MtgBs have no homology with known microbial methyltransferases and are present only in bathyarchaeial lineages.Heterologous expression of the mtgB gene confirmed O-demethylation activity.The mtgB genes were identified in metagenomic data sets from a wide range of coastal sediments,and they were highly expressed in coastal sediments from the East China Sea.These findings suggest that Bathyarchaeia,capable of O-demethylation via their novel and specific methyltransferases,are ubiquitous in coastal sediments.
基金supported by the Zhejiang Provincial Natural Science Foundation of China(LY23B060006 and LY18B060016).
文摘SAPO-5 zeolite supported RuMn was a highly efficient catalyst for the aqueous-phase selective hydrodeoxygenation of guaiacol to cyclohexanol.The optimal catalyst achieved a high cyclohexanol yield of 93.7%at full guaiacol conversion under mild conditions,with a high TOF of 920 h^(-1).Moreover,the catalyst displayed remarkable performance for the hydrogenation of phenol to cyclohexanol,where a 100%yield of cyclohexanol was obtained at a phenol-to-Ru molar ratio of about 17900.In particular,the catalyst exhibited excellent recyclability and could be recycled for 20 times without obvious activity loss.The as-prepared RuMn/SAPO-5 catalyst exhibited higher performance than most of the reported Rubased catalysts.
基金supported by the National Natural Science Foundation of China(22278155,U23A6005)。
文摘Lignin-derived hard carbon shows potential as an anode material for sodium-ion batteries(SIBs)due to its high carbon content and aromatic structure,but its limited reversible adsorption sites and low conductivity hinder performance.This study introduces a self-activation strategy to optimize carbon layer stacking and surface functional groups in microporous carbon,significantly enhancing sodium storage capacity and rate performance.By utilizing oxygen-containing functional groups in organic solvent lignin,we induce micropore formation during pyrolysis,effectively regulating graphite domains and closed pores structures without disrupting carbon layer growth.Unstacked graphene layers serve as efficient electron transport channels and expose additional adsorption sites,simultaneously increasing sodium storage capacity and intrinsic conductivity.The resultant S-OLHC demonstrates a remarkable sodium storage capacity of 358 mA h/g at 0.05 A/g after 200 cycles and maintains 231 mA h/g after 1000 cycles at 2 A/g.This strategy eliminates the need for additional pore-forming agents,offering a simpler,more efficient,and environmentally friendly approach compared to traditional activation methods.This work advances the rational design of high-performance biomass-derived hard carbon for SIBs by leveraging inherent structural characteristics and provides a sustainable low-carbon strategy for lignin valorization in renewable energy storage.
基金the financial support from the National Natural Science Foundation of China(No.21373091)the Science and Technology Project of Guangzhou City(No.201704030040).
文摘Nowadays,hierarchically macro-/meso-/microporous 3D carbon materials have been paid more attention due to their imaginative application potential in specific electrochemistry.Here,we report a dualtemplate strategy using eutectic NaCl/ZnCl2 melt as airtight and swelling agent to obtain 3D mesoporous skeleton structured carbon from renewable lignin.The prepared lignin-derived biocarbon material(LN-3-1)has a high specific surface area(1289 m^2 g^-1),a large pore volume(2.80 cm^3 g^-1),and a well-connected and stable structure.LN-3-1 exhibits extremely high activity and stability in acidic medium for oxygen reduction reaction(ORR),superior to Pt/C catalyst and most non noble-metal catalysts reported in recent literatures.The prepared carbon material was used as a cathode catalyst to assemble a H2-O2 single fuel cell,and its excellent catalytic performance has been confirmed with the maximum power density of 779 mW cm^-2,which is one of the highest power densities among non-metallic catalysts so far.Density functional theory(DFT)calculations indicate that the synergy of chlorine and nitrogen reconciles the intermediate adsorption energies,leading to an appropriate theoretical ORR onset potential.We develop a cost-effective and highly efficient method to prepare biocarbon catalyst for ORR in proton-exchange membrane fuel cells.
基金supported by the National Natural Science Foundation of China(Nos.41276198 and 41406217)the Chinese Polar Environmental Comprehensive Investigation&Assessment Programs(CHINARE 2014-04-01-07,CHINARE 2014-02-01-05)+1 种基金the Chinese Polar Science Strategy Research Foundation(No.20120104)the Zhejiang University Fundamental Research Funds for the Central Universities 2013QNA4037
文摘In this study, lignin-derived phenols were used to determine the sources and distribution of sedimentary organic matter along the northern Bering Sea and Chukchi Sea of the Arctic Ocean. The lignin parameter syringyl/vanillyl（S/V） and cinnamyl/vanillyl（C/V） ratios are used to indicate vegetation sources; and the ratios of vanillic acid/vanillin,（Ad/Al）v and syringic acid/syringaldehyde,（Ad/Al）s are used as indicators of lignin diagenesis. Results showed the predominance of woody gymnosperm signal at the easternmost location in the northern Bering Sea, a mixture of refractory non-woody angiosperm and fresher gymnosperm tissues in the Chukchi Sea, and signal of fresher woody gymnosperm tissues in the northernmost locations in the Chukchi Sea. The lignin materials showed gradual increase in decomposition stage during transport along the northern Bering Sea. Hydrodynamic sorting process, which is the retention of coarser materials nearshore and transportation of finer particles farther offshore, most probably occurred along the east coast of the northern Bering Sea. In Chukchi Sea, the non-woody angiosperm tissues could have originated from the Canadian Arctic and gymnosperm tissues could be from the Russian Arctic side. The fresher materials in the northernmost Chukchi Sea could have been transported here via the ice-rafting process.Detection of fresh lignin materials and the occurrence of lignin decomposition mean that this region could be sensitive to the impact of climate change.
