The development of stimuli-responsive switching memory devices and the elucidation of their switching mechanisms in specific environments are crucial for advancing the field of molecular electronics.Herein,we propose ...The development of stimuli-responsive switching memory devices and the elucidation of their switching mechanisms in specific environments are crucial for advancing the field of molecular electronics.Herein,we propose two distinct two-dimensional covalent organic frameworks(COFs),namely Py-EDA and Py-BDA,incorporating acetylene(-C≡C-)or diacetylene(-C≡C-C≡C-)moieties,respectively,targeting fabricate memory devices exhibiting stimuli-responsive switching behavior.Our findings demonstrate that the incorporation of acetylene units effectively modulates the electronic band structure and enhances the degree ofπ-conjugation,resulting in devices that exhibit typical bipolar nonvolatile memory performance.Notably,upon thermal treatment,the memory behavior of the ITO/Py-BDA/Ag device transitions to a write-once-read-many-times(WORM)mode,displaying decreased SET voltage,increased ON/OFF current ratio,and remarkable retention reliability and cycle stability.This switching behavior is attributed to the occurrence of interlayer solid-state topological polymerization at 350℃,leading to the transformation of diacetylene columnar arrays into enyne chains within Py-BDA,thereby further promoting interlayer charge transfer and separation.展开更多
Transition metal-based electrocatalysts are a promising alternative to noble metal catalysts for electrochemical upgrading of biomass-derived 5-hydroxymethylfurfural(HMF)into high-value 2,5-furandicarboxylic acid(FDCA...Transition metal-based electrocatalysts are a promising alternative to noble metal catalysts for electrochemical upgrading of biomass-derived 5-hydroxymethylfurfural(HMF)into high-value 2,5-furandicarboxylic acid(FDCA).However,the rational design of efficient electrocatalysts with precisely tailored structure-activity correlations remains a critical challenge.Herein,we report a hierarchically structured self-supporting electrode(Vo-NiCo(OH)_(2)-NF)synthesized through in situ electrochemical reconstruction of NiCo-Prussian blue analogue(NiCo-PBA)precursor,in which oxygen vacancy(Vo)-rich Co-doped Ni(OH)_(2)nanosheet arrays are vertically aligned on nickel foam(NF),creating an interconnected conductive network.When evaluated for the HMF oxidation reaction(HMFOR),Vo-NiCo(OH)_(2)-NF exhibits exceptional electrochemical performance,achieving near-complete HMF conversion(99%),ultrahigh FDCA Faradaic efficiency(97.5%),and remarkable product yield(96.2%)at 1.45 V,outperforming conventional Co-doped Ni(OH)_(2)(NiCo(OH)_(2)-NF)and pristine Ni(OH)_(2)(Ni(OH)_(2)-NF)electrodes.By combining in situ spectroscopic characterization and theoretical calculations,we elucidate that the synergistic effects of Co-doping and oxygen vacancy engineering effectively modulate the electronic structure of Ni active centers,favor the formation of high-valent Ni^(3+)species,and optimize HMF adsorption,thereby improving the HMFOR performance.This work provides valuable mechanistic insights for catalyst design and may inspire the development of advanced transition metal-based electrodes for efficient biomass conversion systems.展开更多
Transition metal phosphides(TMPs)have emerged as promising alternatives to commercial noblemetal-based electrocatalysts for the hydrogen evolution reaction(HER).However,their electrocatalytic performance is still far ...Transition metal phosphides(TMPs)have emerged as promising alternatives to commercial noblemetal-based electrocatalysts for the hydrogen evolution reaction(HER).However,their electrocatalytic performance is still far from practical application.Herein,a novel self-supported CoP-based electrode(MoZn-CoP/CC)was prepared,in which Mo and Zn co-doped CoP nanosheet arrays are tightly anchored on a carbon cloth(CC)matrix.Remarkably,the as-prepared MoZn-CoP/CC electrode exhibits outstanding HER performance with exceptional pH universality.More importantly,it only requires modest overpotentials to deliver the current densities exceeding1.0 A cm^(-2)in both alkaline and acidic media,outperforming the commercial Pt catalyst.Experimental results combined with theoretical analysis reveal that co-doping of Mo and Zn can modulate the electronic structure of CoP,thereby optimizing the adsorption energy of hydrogen and ultimately improving the HER performance.This work provides an effective strategy to tune the electronic properties of TMPs via heteroatom doping for enhancing their electrocatalytic performance.展开更多
CO_(2) hydrogenation to CH3OH is of great significance for achieving carbon neutrality.Here,we show a urea-assisted grinding strategy for synthesizing Cu-Zn-Ce ternary catalysts(CZC-G)with optimized interfacial synerg...CO_(2) hydrogenation to CH3OH is of great significance for achieving carbon neutrality.Here,we show a urea-assisted grinding strategy for synthesizing Cu-Zn-Ce ternary catalysts(CZC-G)with optimized interfacial synergy,achieving superior performance in CO_(2) hydrogenation to methanol.The CZC-G catalyst demonstrated exceptional methanol selectivity(96.8%)and a space-time yield of 73.6 gMeOH·kgcat^(–1)·h^(–1) under optimized conditions.Long-term stability tests confirmed no obvious deactivation over 100 h of continuous operation.Structural and mechanistic analyses revealed that the urea-assisted grinding method promotes the formation of Cu/Zn-O_(v)-Ce ternary interfaces and inhibits the reduction of ZnO,enabling synergistic interactions for efficient CO_(2) activation and selective stabilization of formate intermediates(HCOO^(*)),which are critical for methanol synthesis.In-situ diffuse reflectance infrared Fourier transform spectra and X-ray absorption spectroscopy studies elucidated the reaction pathway dominated by the formate mechanism,while suppressing the reverse water-gas shift reaction.This work underscores the critical role of synthetic methodologies in engineering interfacial structures,offering a strategy for designing high-performance catalysts for sustainable CO_(2) resource utilization.展开更多
Elucidating the structure-property-activity relationship in fluorinated COFs is crucial for advancing the rational design of high-performance COF-based photocatalysts.Despite its significance in guiding the developmen...Elucidating the structure-property-activity relationship in fluorinated COFs is crucial for advancing the rational design of high-performance COF-based photocatalysts.Despite its significance in guiding the development of next-generation fluorinated COF photocatalysts,the interplay between the quantity,spatial distribution,and integration sites of functional groups within the COF's backbone at the molecular level remains underexplored.To address this,we propose a controlled fluorination molecular engineering strategy to systematically elucidate this relationship.By precisely tuning the number and positional arrangement of fluorine atoms,we effectively enhance carrier dynamics and interfacial reaction kinetics,thereby driving efficient photocatalytic hydrogen evolution reaction.Notably,the optimized TP-COF-F-3 exhibited an apparent quantum yield of 4.09%at 500 nm,outperforming most reported COF-based photocatalysts.These findings underscore a transformative approach to the molecular design of COF photocatalysts,providing insights for the development of advanced and sustainable photocatalytic systems.展开更多
Electrocatalytic CO_(2)reduction reaction(CO_(2)RR)driven by renewable electricity is crucial for sustainable energy cycles and carbon neutrality.Developing cost-effective and efficient electrocatalysts remains a key ...Electrocatalytic CO_(2)reduction reaction(CO_(2)RR)driven by renewable electricity is crucial for sustainable energy cycles and carbon neutrality.Developing cost-effective and efficient electrocatalysts remains a key challenge.Herein,we report a fluorine-regulated Ni single-atom catalyst(NiFN-900)prepared by self-assembly of biomass and phthalocyanine molecules,and the subsequent controllable pyrolysis process,which exhibits remarkable CO_(2)RR performance,achieving industrial-level current density(>200 mA cm^(-2))and Faradaic efficiency(>90%)toward the CO_(2)-to-CO conversion under pH-universal conditions.Detailed theoretical analysis revealed that the synergistic effectsof pyrrolic N-coordinated Ni sites and the semi-ionic C-F bonds simultaneously optimize the adsorption of ^(*)CooH intermediates by d-orbital modulation and suppress the hydrogen evolution reaction by altering surface affinity of ^(*)H species.This dual functionality enables exceptional pH-universal CO_(2)RR performance.Our low-cost,biomass-derived approach offers scalable electrocatalyst design for practical CO_(2)utilizations.展开更多
The investigation of charge carrier kinetics has long been a cornerstone of polymer photocatalysis research.However,the role of proton transport behavior in photocatalytic processes has often been underappreciated,des...The investigation of charge carrier kinetics has long been a cornerstone of polymer photocatalysis research.However,the role of proton transport behavior in photocatalytic processes has often been underappreciated,despite its fundamental importance in proton-coupled electron-transfer reactions.Addressing this gap,we present a novel BF_(2)-bridged covalent organic framework(C2-COF-BF2) that undergoes post-synthetic modification with boron trifluoride,designed to confer a dual functional advantage.Specifically,the incorporated BF_(2) moieties are engineered to induce a donor-acceptor effect and potentially serve as continuous supply sites for activated protons.This bifunctional role not only enhances charge separation and migration while suppressing electron-hole recombination but also facilitates proton transport,thereby enabling improved performance in both photocatalytic hydrogen evolution reaction(HER) and H_(2) O_(2) production.Remarkably,the photocatalytic HER performance of C2-COF-BF2(AQY_(450 nm)= 8.78%) ranks among the highest efficiencies reported for COF-based photocatalysts to date.These findings highlight an innovative pathway for advancing the rational design of COF photocatalysts,offering a synergistic optimization of charge carrier kinetics and mass transfer processes to achieve unprecedented photocatalytic efficiency.展开更多
Metal-free carbon catalysts are promising alternatives to noble-metal electrocatalysts for H_(2)O_(2) production through two electron oxygen reduction reaction(2e−ORR).Herein,a novel bioengineering approach is propose...Metal-free carbon catalysts are promising alternatives to noble-metal electrocatalysts for H_(2)O_(2) production through two electron oxygen reduction reaction(2e−ORR).Herein,a novel bioengineering approach is proposed to prepare N-doped hollow carbon nanoboxes from guanine precursor.The optimized NC-HNBs-550 exhibits an exceptional electrocatalytic performance,achieving a high H_(2)O_(2) Faradaic efficiency(FE)of over 90%across a broad potential window exceeding 0.6 V.Remarkably,when tested in a flow cell configuration,NC-HNBs-550 delivers near-unity FE for H_(2)O_(2) production at industrial-grade current densities,demonstrating its practicality for scalable applications.Impressively,the in situ electro-synthesized H_(2)O_(2) is further employed as a green oxidant for rapid degradation of various organic dyes and even tetracyclines,and high-purity benzoyl peroxide(BPO)synthesis,highlighting its versatility in environmental and chemical applications.Combining experimental and theoretical analyses,we reveal that the superior 2e−ORR activity originates from the abundance of pyrrolic-N species in NC-HNBs,which optimize the adsorption energy of*OOH intermediates and promote selective O_(2) reduction.This work not only advances the rational design of biomass-derived carbon catalysts for sustainable H_(2)O_(2) production but also provides a versatile platform for environmental remediation and value-added chemical production.展开更多
Methanol synthesis via CO_(2)conversion is a“green carbon”route for mitigating the greenhouse effect and recycling carbon resources.However,despite the widespread use of copper-based systems for methanol synthesis i...Methanol synthesis via CO_(2)conversion is a“green carbon”route for mitigating the greenhouse effect and recycling carbon resources.However,despite the widespread use of copper-based systems for methanol synthesis in recent decades,the chemical state of the active Cu species remains controversial.In this study,various Cu/ZnO/SBA-15 catalysts possessing different interfacial structures were engineered by atomic layer deposition(ALD).The optimized Cu/50c-ZnO/SBA-15 afforded the highest mass-specific methanol formation rate of 211.7 gMeOH·kgcat^(-1)·h^(-1)under the conditions of 250℃ and 3.0 MPa.In-depth characterizations indicated that the electronic state of Cu could be modulated by engineering the interfacial structures of the Cu/ZnO series catalysts,and the Cu cation sites(Cu^(δ+)and Cu^(+))are the active centers for methanol synthesis reaction rather than the Cu^(0)sites.Mechanistic analysis demonstrated that HCO_(3)^(*)and CO_(3)^(*)were slowly transformed to HCOO*and further hydrogenated to methanol following the formate-methoxy intermediate route.This work provides an improved understanding of the origin of the methanol synthesis active centers and emphasizes the potential for fabricating next-generation Cu-based catalysts via ALD.展开更多
The development of highly selective,cost-effective,and energy-efficient electrocatalysts is critical for carbon dioxide reduction reaction(CO_(2)RR)to produce high-value products.Herein,we propose a facile strategy to...The development of highly selective,cost-effective,and energy-efficient electrocatalysts is critical for carbon dioxide reduction reaction(CO_(2)RR)to produce high-value products.Herein,we propose a facile strategy to obtain F,N co-doped carbon-coated iron carbide(Fe3C)nanoparticles by using biomolecule guanine and hexadecafluorophthalocyanine iron as raw materials.Remarkably,this method involves only one-step pyrolysis and does not require any guiding agent or sacrificial template.Benefiting from the advantageous surface microenvironment adjustments achieved through graphitic N(GN)and F co-doping,Fe3C@NF-G-1000 demonstrates exceptional efficacy in the electroreduction of CO_(2)to carbon monoxide(CO)with an impressive Faradic efficiency(FEco)up to 98%at the potential of−0.55 V(vs.reversible hydrogen electrode(RHE)).Furthermore,it delivers a remarkable current density of up to−43 mA·cm^(−2)and exhibits virtually no current attenuation over a span of 20 h within the flow cell.Insights from density functional theory(DFT)calculations reveal that the composite structure of GN and F co-doped graphitic layer and Fe3C exhibits different electron density distributions from that of iron carbide nanoparticles.This is attributed to the synergistic effect of the composite structure leading to the enrichment of electrons in the graphite layer on the surface,which contributes to the stability of the key reaction intermediate*COOH,thus,resulting in an enhanced catalytic activity and efficiency.Overall,this work introduces a new and promising approach to the design of green and low-cost carbon-coated metal materials for CO_(2)reduction reactions.展开更多
基金supported by the National Natural Science Foundation of China(21972021)the Natural Science Foundation of Fujian Province(2024J01238)the 111 Project(D16008)。
文摘The development of stimuli-responsive switching memory devices and the elucidation of their switching mechanisms in specific environments are crucial for advancing the field of molecular electronics.Herein,we propose two distinct two-dimensional covalent organic frameworks(COFs),namely Py-EDA and Py-BDA,incorporating acetylene(-C≡C-)or diacetylene(-C≡C-C≡C-)moieties,respectively,targeting fabricate memory devices exhibiting stimuli-responsive switching behavior.Our findings demonstrate that the incorporation of acetylene units effectively modulates the electronic band structure and enhances the degree ofπ-conjugation,resulting in devices that exhibit typical bipolar nonvolatile memory performance.Notably,upon thermal treatment,the memory behavior of the ITO/Py-BDA/Ag device transitions to a write-once-read-many-times(WORM)mode,displaying decreased SET voltage,increased ON/OFF current ratio,and remarkable retention reliability and cycle stability.This switching behavior is attributed to the occurrence of interlayer solid-state topological polymerization at 350℃,leading to the transformation of diacetylene columnar arrays into enyne chains within Py-BDA,thereby further promoting interlayer charge transfer and separation.
基金financial support of the National Natural Science Foundation of China(NSFC)(22372039 and 22305247)the Natural Science Foundation of Fujian Province of China(2021J06010)the Fuzhou University Testing Fund of Precious Apparatus(2025T022)。
文摘Transition metal-based electrocatalysts are a promising alternative to noble metal catalysts for electrochemical upgrading of biomass-derived 5-hydroxymethylfurfural(HMF)into high-value 2,5-furandicarboxylic acid(FDCA).However,the rational design of efficient electrocatalysts with precisely tailored structure-activity correlations remains a critical challenge.Herein,we report a hierarchically structured self-supporting electrode(Vo-NiCo(OH)_(2)-NF)synthesized through in situ electrochemical reconstruction of NiCo-Prussian blue analogue(NiCo-PBA)precursor,in which oxygen vacancy(Vo)-rich Co-doped Ni(OH)_(2)nanosheet arrays are vertically aligned on nickel foam(NF),creating an interconnected conductive network.When evaluated for the HMF oxidation reaction(HMFOR),Vo-NiCo(OH)_(2)-NF exhibits exceptional electrochemical performance,achieving near-complete HMF conversion(99%),ultrahigh FDCA Faradaic efficiency(97.5%),and remarkable product yield(96.2%)at 1.45 V,outperforming conventional Co-doped Ni(OH)_(2)(NiCo(OH)_(2)-NF)and pristine Ni(OH)_(2)(Ni(OH)_(2)-NF)electrodes.By combining in situ spectroscopic characterization and theoretical calculations,we elucidate that the synergistic effects of Co-doping and oxygen vacancy engineering effectively modulate the electronic structure of Ni active centers,favor the formation of high-valent Ni^(3+)species,and optimize HMF adsorption,thereby improving the HMFOR performance.This work provides valuable mechanistic insights for catalyst design and may inspire the development of advanced transition metal-based electrodes for efficient biomass conversion systems.
基金financially supported by the National Key Research and Development Program of China(No.2024YFE0211500)the National Natural Science Foundation of China(Nos.52332007 and 22305247)the Natural Science Foundation of Fujian Province(Nos.2022L3092 and 2022J05086)
文摘Transition metal phosphides(TMPs)have emerged as promising alternatives to commercial noblemetal-based electrocatalysts for the hydrogen evolution reaction(HER).However,their electrocatalytic performance is still far from practical application.Herein,a novel self-supported CoP-based electrode(MoZn-CoP/CC)was prepared,in which Mo and Zn co-doped CoP nanosheet arrays are tightly anchored on a carbon cloth(CC)matrix.Remarkably,the as-prepared MoZn-CoP/CC electrode exhibits outstanding HER performance with exceptional pH universality.More importantly,it only requires modest overpotentials to deliver the current densities exceeding1.0 A cm^(-2)in both alkaline and acidic media,outperforming the commercial Pt catalyst.Experimental results combined with theoretical analysis reveal that co-doping of Mo and Zn can modulate the electronic structure of CoP,thereby optimizing the adsorption energy of hydrogen and ultimately improving the HER performance.This work provides an effective strategy to tune the electronic properties of TMPs via heteroatom doping for enhancing their electrocatalytic performance.
文摘CO_(2) hydrogenation to CH3OH is of great significance for achieving carbon neutrality.Here,we show a urea-assisted grinding strategy for synthesizing Cu-Zn-Ce ternary catalysts(CZC-G)with optimized interfacial synergy,achieving superior performance in CO_(2) hydrogenation to methanol.The CZC-G catalyst demonstrated exceptional methanol selectivity(96.8%)and a space-time yield of 73.6 gMeOH·kgcat^(–1)·h^(–1) under optimized conditions.Long-term stability tests confirmed no obvious deactivation over 100 h of continuous operation.Structural and mechanistic analyses revealed that the urea-assisted grinding method promotes the formation of Cu/Zn-O_(v)-Ce ternary interfaces and inhibits the reduction of ZnO,enabling synergistic interactions for efficient CO_(2) activation and selective stabilization of formate intermediates(HCOO^(*)),which are critical for methanol synthesis.In-situ diffuse reflectance infrared Fourier transform spectra and X-ray absorption spectroscopy studies elucidated the reaction pathway dominated by the formate mechanism,while suppressing the reverse water-gas shift reaction.This work underscores the critical role of synthetic methodologies in engineering interfacial structures,offering a strategy for designing high-performance catalysts for sustainable CO_(2) resource utilization.
基金supported by the National Natural Science Foundation of China(22572031)the Natural Science Foundation of Fujian Province(2024J01238)the 111 Project(D16008).
文摘Elucidating the structure-property-activity relationship in fluorinated COFs is crucial for advancing the rational design of high-performance COF-based photocatalysts.Despite its significance in guiding the development of next-generation fluorinated COF photocatalysts,the interplay between the quantity,spatial distribution,and integration sites of functional groups within the COF's backbone at the molecular level remains underexplored.To address this,we propose a controlled fluorination molecular engineering strategy to systematically elucidate this relationship.By precisely tuning the number and positional arrangement of fluorine atoms,we effectively enhance carrier dynamics and interfacial reaction kinetics,thereby driving efficient photocatalytic hydrogen evolution reaction.Notably,the optimized TP-COF-F-3 exhibited an apparent quantum yield of 4.09%at 500 nm,outperforming most reported COF-based photocatalysts.These findings underscore a transformative approach to the molecular design of COF photocatalysts,providing insights for the development of advanced and sustainable photocatalytic systems.
基金support of the National Nat-ural Science Foundation of China(NSFC)(22372039 and 22305247)the Fuzhou University Testing Fund of precious apparatus(2025T022).
文摘Electrocatalytic CO_(2)reduction reaction(CO_(2)RR)driven by renewable electricity is crucial for sustainable energy cycles and carbon neutrality.Developing cost-effective and efficient electrocatalysts remains a key challenge.Herein,we report a fluorine-regulated Ni single-atom catalyst(NiFN-900)prepared by self-assembly of biomass and phthalocyanine molecules,and the subsequent controllable pyrolysis process,which exhibits remarkable CO_(2)RR performance,achieving industrial-level current density(>200 mA cm^(-2))and Faradaic efficiency(>90%)toward the CO_(2)-to-CO conversion under pH-universal conditions.Detailed theoretical analysis revealed that the synergistic effectsof pyrrolic N-coordinated Ni sites and the semi-ionic C-F bonds simultaneously optimize the adsorption of ^(*)CooH intermediates by d-orbital modulation and suppress the hydrogen evolution reaction by altering surface affinity of ^(*)H species.This dual functionality enables exceptional pH-universal CO_(2)RR performance.Our low-cost,biomass-derived approach offers scalable electrocatalyst design for practical CO_(2)utilizations.
基金supported by the National Natural Science Foundation of China (21972021,22271281,22325109,22171263,62227815,91961115,22494633,22422508)the Natural Science Foundation of Fujian Province (2024J01238,2022J06032,2021J02017)+5 种基金the Scientific Research and Equipment Development Project of Chinese Academy of Sciences (YJKYQ20210024)the Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China (2021ZR101)the Self-deployment Project Research Program of Haixi Institutes,Chinese Academy of Sciences (CXZX-2022-GH09,CXZX-2023-GS03,CXZX-2022-JQ03)the Key Research Project of Chinese Academy of Sciences(KGFZD-145-25-21)the Strategic Priority Research Program of Chinese Academy of Sciences (XDB1170000)the 111 Project (D16008)。
文摘The investigation of charge carrier kinetics has long been a cornerstone of polymer photocatalysis research.However,the role of proton transport behavior in photocatalytic processes has often been underappreciated,despite its fundamental importance in proton-coupled electron-transfer reactions.Addressing this gap,we present a novel BF_(2)-bridged covalent organic framework(C2-COF-BF2) that undergoes post-synthetic modification with boron trifluoride,designed to confer a dual functional advantage.Specifically,the incorporated BF_(2) moieties are engineered to induce a donor-acceptor effect and potentially serve as continuous supply sites for activated protons.This bifunctional role not only enhances charge separation and migration while suppressing electron-hole recombination but also facilitates proton transport,thereby enabling improved performance in both photocatalytic hydrogen evolution reaction(HER) and H_(2) O_(2) production.Remarkably,the photocatalytic HER performance of C2-COF-BF2(AQY_(450 nm)= 8.78%) ranks among the highest efficiencies reported for COF-based photocatalysts to date.These findings highlight an innovative pathway for advancing the rational design of COF photocatalysts,offering a synergistic optimization of charge carrier kinetics and mass transfer processes to achieve unprecedented photocatalytic efficiency.
基金supported by the National Natural Science Foundation of China(Nos.22372039 and 22305247)the Natural Science Foundation of Fujian Province of China(No.2021J06010)the Fuzhou University Testing Fund of precious apparatus(No.2025T022).
文摘Metal-free carbon catalysts are promising alternatives to noble-metal electrocatalysts for H_(2)O_(2) production through two electron oxygen reduction reaction(2e−ORR).Herein,a novel bioengineering approach is proposed to prepare N-doped hollow carbon nanoboxes from guanine precursor.The optimized NC-HNBs-550 exhibits an exceptional electrocatalytic performance,achieving a high H_(2)O_(2) Faradaic efficiency(FE)of over 90%across a broad potential window exceeding 0.6 V.Remarkably,when tested in a flow cell configuration,NC-HNBs-550 delivers near-unity FE for H_(2)O_(2) production at industrial-grade current densities,demonstrating its practicality for scalable applications.Impressively,the in situ electro-synthesized H_(2)O_(2) is further employed as a green oxidant for rapid degradation of various organic dyes and even tetracyclines,and high-purity benzoyl peroxide(BPO)synthesis,highlighting its versatility in environmental and chemical applications.Combining experimental and theoretical analyses,we reveal that the superior 2e−ORR activity originates from the abundance of pyrrolic-N species in NC-HNBs,which optimize the adsorption energy of*OOH intermediates and promote selective O_(2) reduction.This work not only advances the rational design of biomass-derived carbon catalysts for sustainable H_(2)O_(2) production but also provides a versatile platform for environmental remediation and value-added chemical production.
基金supported by the National Key Research and Development Program of China(2022YFB4101800)the National Natural Science Foundation of China(22172032 and U22A20431).
文摘Methanol synthesis via CO_(2)conversion is a“green carbon”route for mitigating the greenhouse effect and recycling carbon resources.However,despite the widespread use of copper-based systems for methanol synthesis in recent decades,the chemical state of the active Cu species remains controversial.In this study,various Cu/ZnO/SBA-15 catalysts possessing different interfacial structures were engineered by atomic layer deposition(ALD).The optimized Cu/50c-ZnO/SBA-15 afforded the highest mass-specific methanol formation rate of 211.7 gMeOH·kgcat^(-1)·h^(-1)under the conditions of 250℃ and 3.0 MPa.In-depth characterizations indicated that the electronic state of Cu could be modulated by engineering the interfacial structures of the Cu/ZnO series catalysts,and the Cu cation sites(Cu^(δ+)and Cu^(+))are the active centers for methanol synthesis reaction rather than the Cu^(0)sites.Mechanistic analysis demonstrated that HCO_(3)^(*)and CO_(3)^(*)were slowly transformed to HCOO*and further hydrogenated to methanol following the formate-methoxy intermediate route.This work provides an improved understanding of the origin of the methanol synthesis active centers and emphasizes the potential for fabricating next-generation Cu-based catalysts via ALD.
基金the financial support from the National Natural Science Foundation of China(Nos.22072018 and 22372039)the Natural Science Foundation of Fujian Province of China(No.2021J06010).
文摘The development of highly selective,cost-effective,and energy-efficient electrocatalysts is critical for carbon dioxide reduction reaction(CO_(2)RR)to produce high-value products.Herein,we propose a facile strategy to obtain F,N co-doped carbon-coated iron carbide(Fe3C)nanoparticles by using biomolecule guanine and hexadecafluorophthalocyanine iron as raw materials.Remarkably,this method involves only one-step pyrolysis and does not require any guiding agent or sacrificial template.Benefiting from the advantageous surface microenvironment adjustments achieved through graphitic N(GN)and F co-doping,Fe3C@NF-G-1000 demonstrates exceptional efficacy in the electroreduction of CO_(2)to carbon monoxide(CO)with an impressive Faradic efficiency(FEco)up to 98%at the potential of−0.55 V(vs.reversible hydrogen electrode(RHE)).Furthermore,it delivers a remarkable current density of up to−43 mA·cm^(−2)and exhibits virtually no current attenuation over a span of 20 h within the flow cell.Insights from density functional theory(DFT)calculations reveal that the composite structure of GN and F co-doped graphitic layer and Fe3C exhibits different electron density distributions from that of iron carbide nanoparticles.This is attributed to the synergistic effect of the composite structure leading to the enrichment of electrons in the graphite layer on the surface,which contributes to the stability of the key reaction intermediate*COOH,thus,resulting in an enhanced catalytic activity and efficiency.Overall,this work introduces a new and promising approach to the design of green and low-cost carbon-coated metal materials for CO_(2)reduction reactions.
