The performance of proton exchange membrane fuel cells is heavily dependent on the microstructure of electrode catalyst especially at low catalyst loadings.This work shows a hybrid electrocatalyst consisting of PtNi-W...The performance of proton exchange membrane fuel cells is heavily dependent on the microstructure of electrode catalyst especially at low catalyst loadings.This work shows a hybrid electrocatalyst consisting of PtNi-W alloy nanocrystals loaded on carbon surface with atomically dispersed W sites by a two-step straightforward method.Single-atomic W can be found on the carbon surface,which can form protonic acid sites and establish an extended proton transport network at the catalyst surface.When implemented in membrane electrode assembly as cathode at ultra-low loading of 0.05 mgPt cm^(−2),the peak power density of the cell is enhanced by 64.4%compared to that with the commercial Pt/C catalyst.The theoretical calculation suggests that the single-atomic W possesses a favorable energetics toward the formation of*OOH whereby the intermediates can be efficiently converted and further reduced to water,revealing a interfacial cascade catalysis facilitated by the single-atomic W.This work highlights a novel functional hybrid electrocatalyst design from the atomic level that enables to solve the bottle-neck issues at device level.展开更多
Energy transformation is imminent,and hydrogen energy is one of the important new energy sources.One of the keys to increasing the rate of hydrogen evolution during electrolysis is the use of high-performance catalyst...Energy transformation is imminent,and hydrogen energy is one of the important new energy sources.One of the keys to increasing the rate of hydrogen evolution during electrolysis is the use of high-performance catalysts for oxygen evolution reactions(OER).Single-atom alloys(SAAs)have garnered significant attention because they partially reduce costs and combine the advantages of both single-atom catalysts(SACs)and alloy catalysts.Herein,an efficient pyrolysis strategy based on a mixing and drying process is designed to anchor ultra-small Co cluster particles,combined with Ru single atoms dispersed on nitrogen-doped ultra-thin carbon nanosheets(Ru_(1)Co SAA/NC).The prepared electrocatalyst exhibits superior OER activity and superb stability,demonstrating an overpotential of 238 mV for OER with a current density of 10 mA·cm^(-2) in 0.5 mol/L H_(2)SO_(4).And we also utilized in-situ XAS to detect the oxidation state of Ru sites during OER.All in all,this method achieves cost reductions and efficiency improvements through the design of SAAs,offering new prospects for the structural transformation of clean energy.展开更多
The development of high-efficient and low-cost oxygen reduction reaction(ORR)electrocatalysts is crucial for the practical applications of metal-air batteries.One promising way is to develop Fe single-atom catalysts.H...The development of high-efficient and low-cost oxygen reduction reaction(ORR)electrocatalysts is crucial for the practical applications of metal-air batteries.One promising way is to develop Fe single-atom catalysts.However,the single active center and inherent electronic structure of Fe single-atom catalysts lead to the undesirable adsorption of multiple ORR intermediates.Herein,a charge-asymmetry single-atom alloy(SAA)catalyst with Fe-Cu dual sites supported on nitrogen-doped carbon nanosheet(Fe_(1)Cu SAA/NC)was constructed.Various characterizations manifest the existence of electron interaction between Fe and Cu in Fe_(1)Cu SAA/NC,which facilitates the adsorption of ORR intermediate for fast kinetics.Consequently,the charge-asymmetry Fe_(1)Cu SAA/NC exhibits much faster ORR kinetics with a half-wave potential of 0.917 V vs.reversible hydrogen electrode(RHE),outperforming its counterparts in the references.Furthermore,Fe_(1)Cu SAA/NC still maintains a high half-wave potential with only a drop of 5 mV after 5000 cycles,indicating excellent stability.This work provides a new strategy to design highly active and non-noble metal ORR electrocatalysts,which hold great potential for various catalytic applications.展开更多
Electrochemical coupling hydrogen evolution with biomass reforming reaction(named electrochemical hydrogen and chemical cogeneration(EHCC)),which realizes green hydrogen production and chemical upgrading simultaneousl...Electrochemical coupling hydrogen evolution with biomass reforming reaction(named electrochemical hydrogen and chemical cogeneration(EHCC)),which realizes green hydrogen production and chemical upgrading simultaneously,is a promising method to build a carbon-neutral society.Herein,we analyze the EHCC process by considering the market assessment.The ethanol to acetic acid and hydrogen approach is the most feasible for large-scale hydrogen production.We develop AuCu nanocatalysts,which can selectively oxidize ethanol to acetic acid(>97%)with high long-term activity.The isotopic and in-situ infrared experiments reveal that the promoted water dissociation step by alloying contributes to the enhanced activity of the partial oxidation reaction path.A flow-cell electrolyzer equipped with the AuCu anodic catalyst achieves the steady production of hydrogen and acetic acid simultaneously in both high selectivity(>90%),demonstrating the potential scalable application for green hydrogen production with low energy consumption and high profitability.展开更多
The electrochemical CO_(2) reduction reaction(CO_(2)RR)has received widespread attention as a promising method for producing sustainable chemicals and mitigating the global warming.Here,we demonstrate a general and fa...The electrochemical CO_(2) reduction reaction(CO_(2)RR)has received widespread attention as a promising method for producing sustainable chemicals and mitigating the global warming.Here,we demonstrate a general and facile synthetic route for the metal-nitrogen-carbon(M-N-C)type catalyst by simply calcinating metal acetate and urea with commercial carbon black,which have potential application in CO_(2)RR.The synthesized Ni-NC-600 catalyst has the structure of single Ni atom coordinated with one N atom and three C atoms(Ni-N_(1)C_(3)),which is suggested by X-ray absorption spectroscopy.The Ni-NC-600 catalyst exhibits high CO_(2)RR catalytic performance and a high CO Faraday efficiency above 98%in a wide potential range from-0.7 to-1.3 V(vs.reversible hydrogen electrode(RHE)),superior to most of the reported Ni-N-C catalysts.This work has developed a facile strategy to synthesize high performance CO_(2)RR catalyst.展开更多
The revelation of thermal energy exchange mechanism of human body is challenging yet worthwhile,because it can clearly explain the changes in human symptoms and health status.Understanding,the heat transfer of the ski...The revelation of thermal energy exchange mechanism of human body is challenging yet worthwhile,because it can clearly explain the changes in human symptoms and health status.Understanding,the heat transfer of the skin is significant because the skin is the foremost organ for the energy exchange between the human body and the environment.In order to diagnose the physiological conditions of human skin without causing any damage,it is necessary to use a non-invasive measurement technique by means of a conformal flexible sensor.The harmonic method can minimize the thermal-induced injury to the skin due to its low heat generating properties.A novel type of computational theory assessing skin thermal conductivity,blood perfusion rate of capillaries in the dermis,and superficial subcutaneous tissues was formed by combining the multi-medium thermal diffusion model and the bio-thermal model(Pennes equation).The skins of the hand back of six healthy subjects were measured.It was found that the results revealed no consistent changes in thermal conductivity were observed across genders and ages.The measured blood perfusion rates were within the range of human capillary flow.It was found that female subjects had a higher perfusion rate range(0.0058-0.0061 s^(-1))than male subjects(0.0032-0.0049 s^(-1)),which is consistent with invasive medical studies about the gender difference in blood flow rates and stimulated effects in relaxation situations.展开更多
For electrocatalytic reduction of CO2 to CO,the stabilization of intermediate COOH^* and the desorption of CO^* are two key steps.Pd can easily stabilize COOH^*,whereas the strong CO^* binding to Pd surface results in...For electrocatalytic reduction of CO2 to CO,the stabilization of intermediate COOH^* and the desorption of CO^* are two key steps.Pd can easily stabilize COOH^*,whereas the strong CO^* binding to Pd surface results in severe poisoning,thus lowering catalytic activity and stability for CO2 reduction.On Ag surface,CO^* desorbs readily,while COOH^* requires a relatively high formation energy,leading to a high overpotential.In light of the above issues,we successfully designed the PdAg bimetallic catalyst to circumvent the drawbacks of sole Pd and Ag.The PdAg catalyst with Ag-terminated surface not only shows a much lower overpotential(-0.55 V with CO current density of 1 mA/cm^2)than Ag(−0.76 V),but also delivers a CO/H2 ratio 18 times as high as that for Pd at the potential of-0.75 V vs.RHE.The issue of CO poisoning is significantly alleviated on Ag-terminated PdAg surface,with the stability well retained after 4h electrolysis at-0.75 V vs.RHE.Density functional theory(DFT)calculations reveal that the Ag-terminated PdAg surface features a lowered formation energy for COOH^* and weakened adsorption for CO^*,which both contribute to the enhanced performance for CO2 reduction.展开更多
Doped phosphide is promising in earthabundant element based catalysts for hydrogen evolution reaction(HER). Here we employ ammonium hypophosphite(NH4H2PO2) to synthesize a novel parallel doped catalyst,nitrogen doped ...Doped phosphide is promising in earthabundant element based catalysts for hydrogen evolution reaction(HER). Here we employ ammonium hypophosphite(NH4H2PO2) to synthesize a novel parallel doped catalyst,nitrogen doped molybdenum phosphide nanoparticles(NPs)supported on nitrogen doped carbon nanotubes(N-MoP/N-CNTs). The NH4H2PO2 as a bifunctional agent severs as both phosphidation agent and nitrogen source, which makes the synthetic route simple and efficient. The as-obtained parallel doped N-MoP/N-CNTs show an overpotential of 103±5 mV at 10 mA cm-2, which is 140 mV lower than that of MoP NPs. The enhanced HER performance is attributed to the electronic effect by doped MoP and CNTs supports. This work provides a facile route to synthesize doped phosphides for the potential applications in hydrogen energy.展开更多
Ag is a potential low-cost oxygen reduction reaction(ORR)catalyst in alkaline condition,which is important for the zinc-air batteries.Here,we report that an Ag based single atom catalyst with heteroatom coordination.A...Ag is a potential low-cost oxygen reduction reaction(ORR)catalyst in alkaline condition,which is important for the zinc-air batteries.Here,we report that an Ag based single atom catalyst with heteroatom coordination.Ag1-h-NPClSC,has been synthesized and shown much improved performance towards ORR by manipulating the coordination environment of the Ag center.It shows a high half wave potential(0.896 V)and a high turnover frequency(TOF)(5.9 s^(−1))at 0.85 V,which are higher than the previously reported Ag based catalysts and commercial Pt/C.A zinc-air battery with high peak power density of 270 mW·cm^(−2)is fabricated by using the Ag1-h-NPClSC as air electrode.The high performance is attributed to(1)the hollow structure providing good mass transfer;(2)the single atom metal center structure providing high utility of the Ag;(3)heteroatom coordination environment providing the adjusted binding to the ORR intermediates.Density functional theory(DFT)calculations show that the energy barrier for the formation of OOH*,which is considered as the rate determine step for ORR on Ag nanoparticles,is lowered on Ag1-h-NPClSC,thus improving the ORR activity.This work demonstrates that the well manipulated Ag based single atom catalysts are promising in electrocatalysis.展开更多
Single atom catalysts(SACs)have attracted great attention,yet the quest for highly-efficient catalysts is driven by the current obstacles of ambiguous structure-performance relationship.Here,we report a nature keratin...Single atom catalysts(SACs)have attracted great attention,yet the quest for highly-efficient catalysts is driven by the current obstacles of ambiguous structure-performance relationship.Here,we report a nature keratin-based Fe-S_(1)N_(3)SACs with ultrathin two-dimensional(2D)porous carbon nanosheets structure,by controlling the active center through the precise coordination of sulfur and nitrogen.Compared with natural silk-based Fe-N_(4) catalyst,the Fe-S_(1)N_(3)SACs exhibit excellent Fenton-like oxidation degradation ability.X-ray absorption fine structure(XAFS)and electron paramagnetic resonance(EPR)results confirm that S doping is conducive to electron transfer,to accurately generate·OH with high oxidative degradation capacity at the active site.Therefore,the optimized Fe-S_(1)N_(3)catalyst showed higher oxidation degradation activity for organic pollutant substrates(methylene blue(MB),Rhodamine B(RhB)and phenol),significantly superior to Fe-N_(4) samples.This work is devoted to the treatment and application of natural fibers,which provides a novel method for the synthesis of SACs and the regulation of atomic coordination environment.展开更多
Nanocrystals(NCs)of cesium lead halide perovskites are optically unstable,which prevents their use in optical sensors.The combination of perovskite NCs and metal single atoms(SAs)may be a good solution to this issue.U...Nanocrystals(NCs)of cesium lead halide perovskites are optically unstable,which prevents their use in optical sensors.The combination of perovskite NCs and metal single atoms(SAs)may be a good solution to this issue.Unfortunately,depositing metal SAs on perovskite NCs remains a challenge due to relative weak metal-halide bonds.Herein,we present that,via a photo assisted method using cesium lead halide perovskite NCs as host material to anchor Y single atoms,we successfully synthesize Y SA anchored CsPbBr_(3)NCs(Y-SA/CsPbBr_(3)NCs)with outstanding fluorescence stability through the formation of two Y-O bonds and two Y-Br bonds.In comparison to bare CsPbBr_(3)NCs,Y-SA/CsPbBr_(3)NCs possess more stable optical characteristics.The as-synthesized Y-SA/CsPbBr_(3)NCs can be employed as a colorimetric platform to perform rapid CH_(3)I sensing.Detection limit of 0.044 ppm is exhibited in this approach with excellent anti-interference performance.The YSA/CsPbBr_(3)NCs-based system has been applied to the detection of CH_(3)I in sweet potato samples with satisfying results.展开更多
基金Y.Li acknowledges the financial support from the National Natural Science Foundation of China(No.52171199)X.Ke acknowledges the financial support from the National Natural Science Foundation of China(No.12074017).
文摘The performance of proton exchange membrane fuel cells is heavily dependent on the microstructure of electrode catalyst especially at low catalyst loadings.This work shows a hybrid electrocatalyst consisting of PtNi-W alloy nanocrystals loaded on carbon surface with atomically dispersed W sites by a two-step straightforward method.Single-atomic W can be found on the carbon surface,which can form protonic acid sites and establish an extended proton transport network at the catalyst surface.When implemented in membrane electrode assembly as cathode at ultra-low loading of 0.05 mgPt cm^(−2),the peak power density of the cell is enhanced by 64.4%compared to that with the commercial Pt/C catalyst.The theoretical calculation suggests that the single-atomic W possesses a favorable energetics toward the formation of*OOH whereby the intermediates can be efficiently converted and further reduced to water,revealing a interfacial cascade catalysis facilitated by the single-atomic W.This work highlights a novel functional hybrid electrocatalyst design from the atomic level that enables to solve the bottle-neck issues at device level.
基金supported by the National Natural Science Foundation of China(22375019)Beijing Natural Science Foundation(Grant No.2212018)Beijing Institute of Technology Research Fund Program for Young Scholars(2022CX01011).
文摘Energy transformation is imminent,and hydrogen energy is one of the important new energy sources.One of the keys to increasing the rate of hydrogen evolution during electrolysis is the use of high-performance catalysts for oxygen evolution reactions(OER).Single-atom alloys(SAAs)have garnered significant attention because they partially reduce costs and combine the advantages of both single-atom catalysts(SACs)and alloy catalysts.Herein,an efficient pyrolysis strategy based on a mixing and drying process is designed to anchor ultra-small Co cluster particles,combined with Ru single atoms dispersed on nitrogen-doped ultra-thin carbon nanosheets(Ru_(1)Co SAA/NC).The prepared electrocatalyst exhibits superior OER activity and superb stability,demonstrating an overpotential of 238 mV for OER with a current density of 10 mA·cm^(-2) in 0.5 mol/L H_(2)SO_(4).And we also utilized in-situ XAS to detect the oxidation state of Ru sites during OER.All in all,this method achieves cost reductions and efficiency improvements through the design of SAAs,offering new prospects for the structural transformation of clean energy.
基金National Natural Science Foundation of China(No.51902013).
文摘The development of high-efficient and low-cost oxygen reduction reaction(ORR)electrocatalysts is crucial for the practical applications of metal-air batteries.One promising way is to develop Fe single-atom catalysts.However,the single active center and inherent electronic structure of Fe single-atom catalysts lead to the undesirable adsorption of multiple ORR intermediates.Herein,a charge-asymmetry single-atom alloy(SAA)catalyst with Fe-Cu dual sites supported on nitrogen-doped carbon nanosheet(Fe_(1)Cu SAA/NC)was constructed.Various characterizations manifest the existence of electron interaction between Fe and Cu in Fe_(1)Cu SAA/NC,which facilitates the adsorption of ORR intermediate for fast kinetics.Consequently,the charge-asymmetry Fe_(1)Cu SAA/NC exhibits much faster ORR kinetics with a half-wave potential of 0.917 V vs.reversible hydrogen electrode(RHE),outperforming its counterparts in the references.Furthermore,Fe_(1)Cu SAA/NC still maintains a high half-wave potential with only a drop of 5 mV after 5000 cycles,indicating excellent stability.This work provides a new strategy to design highly active and non-noble metal ORR electrocatalysts,which hold great potential for various catalytic applications.
基金supported by the National Natural Science Foundation of China(Nos.21971008 and 22279004)Beijing Natural Science Foundation(No.Z210016)Fundamental Research Funds for the Central Universities(No.buctrc201916).
文摘Electrochemical coupling hydrogen evolution with biomass reforming reaction(named electrochemical hydrogen and chemical cogeneration(EHCC)),which realizes green hydrogen production and chemical upgrading simultaneously,is a promising method to build a carbon-neutral society.Herein,we analyze the EHCC process by considering the market assessment.The ethanol to acetic acid and hydrogen approach is the most feasible for large-scale hydrogen production.We develop AuCu nanocatalysts,which can selectively oxidize ethanol to acetic acid(>97%)with high long-term activity.The isotopic and in-situ infrared experiments reveal that the promoted water dissociation step by alloying contributes to the enhanced activity of the partial oxidation reaction path.A flow-cell electrolyzer equipped with the AuCu anodic catalyst achieves the steady production of hydrogen and acetic acid simultaneously in both high selectivity(>90%),demonstrating the potential scalable application for green hydrogen production with low energy consumption and high profitability.
基金supported by the National Natural Science Foundation of China(No.21971008).
文摘The electrochemical CO_(2) reduction reaction(CO_(2)RR)has received widespread attention as a promising method for producing sustainable chemicals and mitigating the global warming.Here,we demonstrate a general and facile synthetic route for the metal-nitrogen-carbon(M-N-C)type catalyst by simply calcinating metal acetate and urea with commercial carbon black,which have potential application in CO_(2)RR.The synthesized Ni-NC-600 catalyst has the structure of single Ni atom coordinated with one N atom and three C atoms(Ni-N_(1)C_(3)),which is suggested by X-ray absorption spectroscopy.The Ni-NC-600 catalyst exhibits high CO_(2)RR catalytic performance and a high CO Faraday efficiency above 98%in a wide potential range from-0.7 to-1.3 V(vs.reversible hydrogen electrode(RHE)),superior to most of the reported Ni-N-C catalysts.This work has developed a facile strategy to synthesize high performance CO_(2)RR catalyst.
基金support from the National Natural Science Foundation of China(Nos.52222602,52201261)Beijing Nova Program(No.20220484170)+1 种基金Ningbo 3315 Innovative Teams Program(No.2019A-14-C)Fundamental Research Funds for the Central Universities(Nos.FRF-TP-22-001C1,FRF-EYIT-23-05).
文摘The revelation of thermal energy exchange mechanism of human body is challenging yet worthwhile,because it can clearly explain the changes in human symptoms and health status.Understanding,the heat transfer of the skin is significant because the skin is the foremost organ for the energy exchange between the human body and the environment.In order to diagnose the physiological conditions of human skin without causing any damage,it is necessary to use a non-invasive measurement technique by means of a conformal flexible sensor.The harmonic method can minimize the thermal-induced injury to the skin due to its low heat generating properties.A novel type of computational theory assessing skin thermal conductivity,blood perfusion rate of capillaries in the dermis,and superficial subcutaneous tissues was formed by combining the multi-medium thermal diffusion model and the bio-thermal model(Pennes equation).The skins of the hand back of six healthy subjects were measured.It was found that the results revealed no consistent changes in thermal conductivity were observed across genders and ages.The measured blood perfusion rates were within the range of human capillary flow.It was found that female subjects had a higher perfusion rate range(0.0058-0.0061 s^(-1))than male subjects(0.0032-0.0049 s^(-1)),which is consistent with invasive medical studies about the gender difference in blood flow rates and stimulated effects in relaxation situations.
基金This work was supported by the National Key R&D Program of China(Nos.2016YFA0202801 and 2017YFA0700101)the National Natural Science Foundation of China(Nos.21872076,21573119,21590792,21890383,and 91645203)+1 种基金Beijing Natural Science Foundation(No.JQ18007)The aberration-corrected TEM studies were conducted at the National Center for Electron Microscopy in Beijing for Information Science and Technology.
文摘For electrocatalytic reduction of CO2 to CO,the stabilization of intermediate COOH^* and the desorption of CO^* are two key steps.Pd can easily stabilize COOH^*,whereas the strong CO^* binding to Pd surface results in severe poisoning,thus lowering catalytic activity and stability for CO2 reduction.On Ag surface,CO^* desorbs readily,while COOH^* requires a relatively high formation energy,leading to a high overpotential.In light of the above issues,we successfully designed the PdAg bimetallic catalyst to circumvent the drawbacks of sole Pd and Ag.The PdAg catalyst with Ag-terminated surface not only shows a much lower overpotential(-0.55 V with CO current density of 1 mA/cm^2)than Ag(−0.76 V),but also delivers a CO/H2 ratio 18 times as high as that for Pd at the potential of-0.75 V vs.RHE.The issue of CO poisoning is significantly alleviated on Ag-terminated PdAg surface,with the stability well retained after 4h electrolysis at-0.75 V vs.RHE.Density functional theory(DFT)calculations reveal that the Ag-terminated PdAg surface features a lowered formation energy for COOH^* and weakened adsorption for CO^*,which both contribute to the enhanced performance for CO2 reduction.
基金supported by the National Key Research and Development Program of China (2017YFA0206500)the National Natural Science Foundation of China (21671014)the Fundamental Research Funds for the Central Universities (buctrc201522)
文摘Doped phosphide is promising in earthabundant element based catalysts for hydrogen evolution reaction(HER). Here we employ ammonium hypophosphite(NH4H2PO2) to synthesize a novel parallel doped catalyst,nitrogen doped molybdenum phosphide nanoparticles(NPs)supported on nitrogen doped carbon nanotubes(N-MoP/N-CNTs). The NH4H2PO2 as a bifunctional agent severs as both phosphidation agent and nitrogen source, which makes the synthetic route simple and efficient. The as-obtained parallel doped N-MoP/N-CNTs show an overpotential of 103±5 mV at 10 mA cm-2, which is 140 mV lower than that of MoP NPs. The enhanced HER performance is attributed to the electronic effect by doped MoP and CNTs supports. This work provides a facile route to synthesize doped phosphides for the potential applications in hydrogen energy.
基金the National Key Research and Development Program of China(No.2019YFA0210300)the National Natural Science Foundation of China(No.21971008)Fundamental Research Funds for the Central Universities(Nos.buctrc201916 and buctrc201823).
文摘Ag is a potential low-cost oxygen reduction reaction(ORR)catalyst in alkaline condition,which is important for the zinc-air batteries.Here,we report that an Ag based single atom catalyst with heteroatom coordination.Ag1-h-NPClSC,has been synthesized and shown much improved performance towards ORR by manipulating the coordination environment of the Ag center.It shows a high half wave potential(0.896 V)and a high turnover frequency(TOF)(5.9 s^(−1))at 0.85 V,which are higher than the previously reported Ag based catalysts and commercial Pt/C.A zinc-air battery with high peak power density of 270 mW·cm^(−2)is fabricated by using the Ag1-h-NPClSC as air electrode.The high performance is attributed to(1)the hollow structure providing good mass transfer;(2)the single atom metal center structure providing high utility of the Ag;(3)heteroatom coordination environment providing the adjusted binding to the ORR intermediates.Density functional theory(DFT)calculations show that the energy barrier for the formation of OOH*,which is considered as the rate determine step for ORR on Ag nanoparticles,is lowered on Ag1-h-NPClSC,thus improving the ORR activity.This work demonstrates that the well manipulated Ag based single atom catalysts are promising in electrocatalysis.
基金This work was supported by the Beijing Natural Science Foundation(No.2212018)the National Natural Science Foundation of China(No.22105116)+2 种基金Natural Science Foundation of Hebei Province(No.B2021208001)Key Research and Development Program of Shijiazhuang(No.221070361A)the Beijing Institute of Technology Research Fund Program for Young Scholars。
文摘Single atom catalysts(SACs)have attracted great attention,yet the quest for highly-efficient catalysts is driven by the current obstacles of ambiguous structure-performance relationship.Here,we report a nature keratin-based Fe-S_(1)N_(3)SACs with ultrathin two-dimensional(2D)porous carbon nanosheets structure,by controlling the active center through the precise coordination of sulfur and nitrogen.Compared with natural silk-based Fe-N_(4) catalyst,the Fe-S_(1)N_(3)SACs exhibit excellent Fenton-like oxidation degradation ability.X-ray absorption fine structure(XAFS)and electron paramagnetic resonance(EPR)results confirm that S doping is conducive to electron transfer,to accurately generate·OH with high oxidative degradation capacity at the active site.Therefore,the optimized Fe-S_(1)N_(3)catalyst showed higher oxidation degradation activity for organic pollutant substrates(methylene blue(MB),Rhodamine B(RhB)and phenol),significantly superior to Fe-N_(4) samples.This work is devoted to the treatment and application of natural fibers,which provides a novel method for the synthesis of SACs and the regulation of atomic coordination environment.
基金This work was supported by the Scientific Research Project of Beijing Educational Committee(No.KM202010028007)。
文摘Nanocrystals(NCs)of cesium lead halide perovskites are optically unstable,which prevents their use in optical sensors.The combination of perovskite NCs and metal single atoms(SAs)may be a good solution to this issue.Unfortunately,depositing metal SAs on perovskite NCs remains a challenge due to relative weak metal-halide bonds.Herein,we present that,via a photo assisted method using cesium lead halide perovskite NCs as host material to anchor Y single atoms,we successfully synthesize Y SA anchored CsPbBr_(3)NCs(Y-SA/CsPbBr_(3)NCs)with outstanding fluorescence stability through the formation of two Y-O bonds and two Y-Br bonds.In comparison to bare CsPbBr_(3)NCs,Y-SA/CsPbBr_(3)NCs possess more stable optical characteristics.The as-synthesized Y-SA/CsPbBr_(3)NCs can be employed as a colorimetric platform to perform rapid CH_(3)I sensing.Detection limit of 0.044 ppm is exhibited in this approach with excellent anti-interference performance.The YSA/CsPbBr_(3)NCs-based system has been applied to the detection of CH_(3)I in sweet potato samples with satisfying results.
