Single atom catalysts have been recognized as potential catalysts to fabricate electrochemical biosensors,due to their unexpected catalytic selectivity and activity.Here,we designed and fabricated an ultrasensitive do...Single atom catalysts have been recognized as potential catalysts to fabricate electrochemical biosensors,due to their unexpected catalytic selectivity and activity.Here,we designed and fabricated an ultrasensitive dopamine(DA)sensor based on the flower-like MoS_(2) embellished with single Ni site catalyst(Ni-MoS_(2)).The limit of detection could achieve 1 pM in phosphate buffer solution(PBS,pH=7.4),1 pM in bovine serum(pH=7.4),and 100 pM in artificial urine(pH=6.8).The excellent sensing performance was attributed to the Ni single atom axial anchoring on the Mo atom in the MoS_(2) basal plane with the Ni-S_(3) structure.Both the experiment and density functional theory(DFT)results certify that this structural feature is more favorable for the adsorption and electron transfer of DA on Ni atoms.The high proportion of Ni active sites on MoS_(2) basal plane effectively enhanced the intrinsic electronic conductivity and electrochemical activity toward DA.The successful establishment of this sensor gives a new guide to expand the field of single atom catalyst in the application of biosensors.展开更多
Partial oxidation of methane is a promising alternative strategy for methanol production under mild reaction conditions;however,significant challenges hinder the development of appropriate catalysts.In this study,base...Partial oxidation of methane is a promising alternative strategy for methanol production under mild reaction conditions;however,significant challenges hinder the development of appropriate catalysts.In this study,based on first-principles calculations,we demonstrate that a single Fe atom supported on anatase TiO_(2)(001)provides double active sites(Fe and Ti_(5C))to activate gas-phase O_(2)and form O-assisted intermediates.The triple state Fe-O/TiO_(2)(001)system exhibited better activity for methane activation(ΔG max=1.02 eV).Our findings offer new insights into the design of non-noble-3 d transition metal single-atom catalysts on TiO_(2)(001)for partial methane oxidation via an inexpensive O_(2)oxidant under mild reaction conditions.展开更多
Single-atom catalysts (SACs) have recently attracted broad attention in the catalysis field due to their maximized atom efficiency and unique catalytic properties.An atomic-level understanding of the interaction betwe...Single-atom catalysts (SACs) have recently attracted broad attention in the catalysis field due to their maximized atom efficiency and unique catalytic properties.An atomic-level understanding of the interaction between the metal atoms and support is vital for developing stable and high-performance SACs.In this work,Pt1 single atoms with Ioadings up to 4 wt.% were fabricated on ceria nanorods using the atomic layer deposition technique.To understand the Pt-O-Ce bond interfacial interactions,the stability of Pt1 single atoms in the hydrogen reducing environment was extensively investigated by using in situ diffuse reflectance infrared Fourier transform spectroscopy CO chemisorption measurements.It was found that ceria defect sites,metal Ioadings and high-temperature calcination are effective ways to tune the stability of Pt1 single atoms in the hydrogen environment.X-ray photoemission spectroscopy further showed that Pt1 single atoms on ceria are dominantly at a +2 valence state at the defect and step edge sites,while those on terrace sites are at a +4 state.The above tailored stability and electronic properties of Pt1 single atoms are found to be strongly correlated with the catalytic activity in the dry and water-mediated CO oxidation reactions.展开更多
Well-defined surface structures and uniformity are key factors in exploring structure–activity relationships in heterogeneous catalysts.A modified atomic layer deposition method and three well-defined CeO_(2) nanosha...Well-defined surface structures and uniformity are key factors in exploring structure–activity relationships in heterogeneous catalysts.A modified atomic layer deposition method and three well-defined CeO_(2) nanoshapes,octahedra with(111)surfaces,cubes exposing(100)facets,and rods with(100)and(110)surface facet terminations,were utilized to synthesize ultra-low loading Pt/CeO_(2) catalysts and allow investigations on the influence of ceria surface facet on isolated Pt species under reducing conditions.A mild reduction temperature(150℃)reduces the initial platinum ions present on the surfaces of the ceria support but preserves the isolated Pt atoms on all ceria surface facets.In contrast,a reduction temperature of 350°C,reveals very different interactions between the initial single Pt atoms and the various ceria surface facets,leading to dissimilar and nonuniform Pt ensembles on the three ceria shapes.To isolate facet dependent Pt–CeO_(2) interactions and avoid variations between Pt species,the Pt1/CeO_(2) catalysts after reduction at 150°C were subjected to CO oxidation conditions.The isolated Pt atoms on the CeO_(2) octahedra and cubes are less active in the CO oxidation reaction,compared with Pt on CeO_(2) rods.In the case of Pt on the CeO_(2) octahedra this is due to strongly bound CO blocking active sites together with a stable CeO_(2)(111)surface limiting the oxygen supply from the support.On the CeO_(2) cubes,some Pt is not available for reaction and CO is bound strongly on the available Pt species.In addition,the Pt catalysts supported on the CeO_(2) cubes are not stable with time on stream.The isolated Pt atoms on the CeO_(2) rods are considerably more active under these conditions and this is due to a weaker Pt–CO bond strength and more facile reverse oxygen spillover from the defect-rich(110)surfaces of the rods due to the lower energy of oxygen vacancy formation on this CeO_(2) surface.The Pt supported on the CeO_(2) rods is also remarkably stable with time on stream.This work demonstrates the importance of using ultra-low loadings of active metal and well-defined oxide supports to isolate interactions between single metal atoms and oxide supports and determine the effects of the oxide support surface facet on the active metal at the atomic level.展开更多
基金This work was supported by China Ministry of Science and Technology(No.2021YFA1500404)the Anhui Provincial Natural Science Foundation(Nos.2108085QB70 and 2108085UD06)+4 种基金the DNL Cooperation Fund,CAS(No.DNL201918)the Collaborative Innovation Program of Hefei Science Center,CAS(No.2021HSC-CIP002)the Natural Science Foundation of Hefei,China(No.2021044)the Fundamental Research Funds for the Central Universities(Nos.WK2060000004,WK2060000021,WK2060000025,KY2060000180,and KY2060000195)the Fundamental Research Funds for the Central Universities(No.WK5290000003)。
文摘Single atom catalysts have been recognized as potential catalysts to fabricate electrochemical biosensors,due to their unexpected catalytic selectivity and activity.Here,we designed and fabricated an ultrasensitive dopamine(DA)sensor based on the flower-like MoS_(2) embellished with single Ni site catalyst(Ni-MoS_(2)).The limit of detection could achieve 1 pM in phosphate buffer solution(PBS,pH=7.4),1 pM in bovine serum(pH=7.4),and 100 pM in artificial urine(pH=6.8).The excellent sensing performance was attributed to the Ni single atom axial anchoring on the Mo atom in the MoS_(2) basal plane with the Ni-S_(3) structure.Both the experiment and density functional theory(DFT)results certify that this structural feature is more favorable for the adsorption and electron transfer of DA on Ni atoms.The high proportion of Ni active sites on MoS_(2) basal plane effectively enhanced the intrinsic electronic conductivity and electrochemical activity toward DA.The successful establishment of this sensor gives a new guide to expand the field of single atom catalyst in the application of biosensors.
基金the Guangdong Innovation Research Team for Higher Education(2017KCXTD030)High-level Talents Project of Dongguan University of Technology(KCYKYQD2017017)+2 种基金Research Center of New Energy Materials(KCYCXPT2017005)Engineering Research Center of Non-food Biomass Efficient Pyrolysis and Utilization Technology of Guangdong Higher Education Institutes(2016GCZX009)Guangdong Basic and Ap-plied Basic Research Foundation(2021A1515110702).
文摘Partial oxidation of methane is a promising alternative strategy for methanol production under mild reaction conditions;however,significant challenges hinder the development of appropriate catalysts.In this study,based on first-principles calculations,we demonstrate that a single Fe atom supported on anatase TiO_(2)(001)provides double active sites(Fe and Ti_(5C))to activate gas-phase O_(2)and form O-assisted intermediates.The triple state Fe-O/TiO_(2)(001)system exhibited better activity for methane activation(ΔG max=1.02 eV).Our findings offer new insights into the design of non-noble-3 d transition metal single-atom catalysts on TiO_(2)(001)for partial methane oxidation via an inexpensive O_(2)oxidant under mild reaction conditions.
基金the National Natural Science Foundation of China (Nos.21673215 and 21473169)the Fundamental Research Funds for the Central Universities (No.WK2060030029)the Max-Planck Partner Group,Hefei Science Center,CAS,Users with Potential. The authors also gratefully thank the BL10B beamlines at National Synchrotron Radiation Laboratory (NSRL),China.
文摘Single-atom catalysts (SACs) have recently attracted broad attention in the catalysis field due to their maximized atom efficiency and unique catalytic properties.An atomic-level understanding of the interaction between the metal atoms and support is vital for developing stable and high-performance SACs.In this work,Pt1 single atoms with Ioadings up to 4 wt.% were fabricated on ceria nanorods using the atomic layer deposition technique.To understand the Pt-O-Ce bond interfacial interactions,the stability of Pt1 single atoms in the hydrogen reducing environment was extensively investigated by using in situ diffuse reflectance infrared Fourier transform spectroscopy CO chemisorption measurements.It was found that ceria defect sites,metal Ioadings and high-temperature calcination are effective ways to tune the stability of Pt1 single atoms in the hydrogen environment.X-ray photoemission spectroscopy further showed that Pt1 single atoms on ceria are dominantly at a +2 valence state at the defect and step edge sites,while those on terrace sites are at a +4 state.The above tailored stability and electronic properties of Pt1 single atoms are found to be strongly correlated with the catalytic activity in the dry and water-mediated CO oxidation reactions.
基金supported by the National Science Foundation(NSF)(CHE-1507230 and CBET-1933723)the National High Magnetic Field Laboratory,which is supported by the NSF Cooperative Agreement(DMR-1644779)and the State of Florida.Startup funding from the University of Florida is also gratefully acknowledged.
文摘Well-defined surface structures and uniformity are key factors in exploring structure–activity relationships in heterogeneous catalysts.A modified atomic layer deposition method and three well-defined CeO_(2) nanoshapes,octahedra with(111)surfaces,cubes exposing(100)facets,and rods with(100)and(110)surface facet terminations,were utilized to synthesize ultra-low loading Pt/CeO_(2) catalysts and allow investigations on the influence of ceria surface facet on isolated Pt species under reducing conditions.A mild reduction temperature(150℃)reduces the initial platinum ions present on the surfaces of the ceria support but preserves the isolated Pt atoms on all ceria surface facets.In contrast,a reduction temperature of 350°C,reveals very different interactions between the initial single Pt atoms and the various ceria surface facets,leading to dissimilar and nonuniform Pt ensembles on the three ceria shapes.To isolate facet dependent Pt–CeO_(2) interactions and avoid variations between Pt species,the Pt1/CeO_(2) catalysts after reduction at 150°C were subjected to CO oxidation conditions.The isolated Pt atoms on the CeO_(2) octahedra and cubes are less active in the CO oxidation reaction,compared with Pt on CeO_(2) rods.In the case of Pt on the CeO_(2) octahedra this is due to strongly bound CO blocking active sites together with a stable CeO_(2)(111)surface limiting the oxygen supply from the support.On the CeO_(2) cubes,some Pt is not available for reaction and CO is bound strongly on the available Pt species.In addition,the Pt catalysts supported on the CeO_(2) cubes are not stable with time on stream.The isolated Pt atoms on the CeO_(2) rods are considerably more active under these conditions and this is due to a weaker Pt–CO bond strength and more facile reverse oxygen spillover from the defect-rich(110)surfaces of the rods due to the lower energy of oxygen vacancy formation on this CeO_(2) surface.The Pt supported on the CeO_(2) rods is also remarkably stable with time on stream.This work demonstrates the importance of using ultra-low loadings of active metal and well-defined oxide supports to isolate interactions between single metal atoms and oxide supports and determine the effects of the oxide support surface facet on the active metal at the atomic level.
