The sluggish kinetics of the oxygen reduction reaction(ORR)is the bottleneck for various electrochemical energy conversion devices.Regulating the electronic structure of electrocatalysts by ligands has received partic...The sluggish kinetics of the oxygen reduction reaction(ORR)is the bottleneck for various electrochemical energy conversion devices.Regulating the electronic structure of electrocatalysts by ligands has received particular attention in deriving valid ORR electrocatalysts.Here,the surface electronic structure of Ptbased noble metal aerogels(NMAs)was modulated by various organic ligands,among which the electron-withdrawing ligand of 4-methylphenylene effectively boosted the ORR electrocatalysis.Theoretical calculations suggested the smaller energy barrier for the transformation of O^(*) to OH^(*) and downshift the d-band center of Pt due to the interaction between 4-methylphenylene and the surface metals,thus enhancing the ORR intrinsic activity.Both Pt3Ni and Pt Pd aerogels with 4-methylphenylene decoration performed significant enhancement in ORR activity and durability in different media.Remarkably,the 4-methylphenylene modified Pt Pd aerogel exhibited the higher halfwave potential of 0.952 V and the mass activity of 10.2 times of commercial Pt/C.This work explained the effect of electronic structure on ORR electrocatalytic properties and would promote functionalized NMAs as efficient ORR electrocatalysts.展开更多
The exploitation of electrocatalysts with high activity and durability for HER is desirable for future energy systems,but it is still a challenge.NMPs have attracted increasing attentions,but the preparation process o...The exploitation of electrocatalysts with high activity and durability for HER is desirable for future energy systems,but it is still a challenge.NMPs have attracted increasing attentions,but the preparation process often needs toxic regents or dangerous reaction conditions.Herein,we develop a general green method to fabricate metal-rich NMPs anchored on NPG through pyrolyzing DNA cross-linked complexes.The obtained Ru_(2) P-NPG exhibits an ultrasmall overpotential of 7 mV at 10 mA cm^(2) and ultralow Tafel slope of 33 mV dec^(-1) in 1.0 mol L?1 KOH,even better than that of commercial Pt/C.In addition,Ru 2 P-NPG also shows low overpotentials of 29 and 78 mV in 0.5 mol L^(-1) H_(2)SO_(4) and 1.0 mol L^(-1) PBS,respectively.The superior activity can be attributed to the ultrafine dispersion of Ru 2 P nanoparticles for more accessible sites,more defects formed for abundant active sites,the two-dimensional plane structure for accelerated electron transfer and mass transport,as well as the regulation of electron distribution of the catalyst.Moreover,the synthetic method can also be applied to prepare other metal-rich noble metal phosphides(Pd_(3)P-NPG and Rh_(2)P-NPG),which also exhibits high activity for HER.This work provides an effective strategy for designing NMP-based electrocatalysts.展开更多
Highly sensitive gas sensors with remarkably low detection limits are attractive for diverse practical application fields including real-time environmental monitoring,exhaled breath diagnosis,and food freshness analys...Highly sensitive gas sensors with remarkably low detection limits are attractive for diverse practical application fields including real-time environmental monitoring,exhaled breath diagnosis,and food freshness analysis.Among various chemiresistive sensing materials,noble metal-decorated semiconducting metal oxides(SMOs)have currently aroused extensive attention by virtue of the unique electronic and catalytic properties of noble metals.This review highlights the research progress on the designs and applications of different noble metal-decorated SMOs with diverse nanostructures(e.g.,nanoparticles,nanowires,nanorods,nanosheets,nanoflowers,and microspheres)for high-performance gas sensors with higher response,faster response/recovery speed,lower operating temperature,and ultra-low detection limits.The key topics include Pt,Pd,Au,other noble metals(e.g.,Ag,Ru,and Rh.),and bimetals-decorated SMOs containing ZnO,SnO_(2),WO_(3),other SMOs(e.g.,In_(2)O_(3),Fe_(2)O_(3),and CuO),and heterostructured SMOs.In addition to conventional devices,the innovative applications like photo-assisted room temperature gas sensors and mechanically flexible smart wearable devices are also discussed.Moreover,the relevant mechanisms for the sensing performance improvement caused by noble metal decoration,including the electronic sensitization effect and the chemical sensitization effect,have also been summarized in detail.Finally,major challenges and future perspectives towards noble metal-decorated SMOs-based chemiresistive gas sensors are proposed.展开更多
Oxidative dehydrogenation of propane with carbon dioxide(CO_(2)-ODP)characterizes the tandem dehydrogenation of propane to propylene with the reduction of the greenhouse gas of CO_(2)to valuable CO.However,the existin...Oxidative dehydrogenation of propane with carbon dioxide(CO_(2)-ODP)characterizes the tandem dehydrogenation of propane to propylene with the reduction of the greenhouse gas of CO_(2)to valuable CO.However,the existing catalyst is limited due to the poor activity and stability,which hinders its industrialization.Herein,we design the finned Zn-MFI zeolite encapsulated noble metal nanoparticles(NPs)as bifunctional catalysts(NPs@Zn-MFI)for CO_(2)-ODP.Characterization results reveal that the Zn2+species are coordinated with the MFI zeolite matrix as isolated cations and the NPs of Pt,Rh,or Rh Pt are highly dispersed in the zeolite crystals.The isolated Zn2+cations are very effective for activating the propane and the small NPs are favorable for activating the CO_(2),which synergistically promote the selective transformation of propane and CO_(2)to propylene and CO.As a result,the optimal 0.25%Rh0.50%Pt@Zn-MFI catalyst shows the best propylene yield,satisfactory CO_(2)conversion,and long-term stability.Moreover,considering the tunable synergetic effects between the isolated cations and NPs,the developed approach offers a general guideline to design more efficient CO_(2)-ODP catalysts,which is validated by the improved performance of the bifunctional catalysts via simply substituting Sn4+cations for Zn2+cations in the MFI zeolite matrix.展开更多
Selective hydrogenation of phenol to cyclohexanone is intriguing in chemical industry.Though a few catalysts with promising performances have been developed in recent years,the basic principle for catalyst design is s...Selective hydrogenation of phenol to cyclohexanone is intriguing in chemical industry.Though a few catalysts with promising performances have been developed in recent years,the basic principle for catalyst design is still missing owing to the unclear catalytic mechanism.This work tries to unravel the mechanism of phenol hydro-genation and the reasons causing the selectivity discrepancy on noble metal catalysts under mild conditions.Results show that different reaction pathways always firstly converge to the formation of cyclohexanone under mild conditions.The selectivity discrepancy mainly depends on the activity for cyclohexanone sequential hy-drogenation,in which two factors are found to be responsible,i.e.the hydrogenation energy barrier and the competitive chemisorption between phenol and cyclohexanone,if the specific co-catalyzing effect of H 2 O on Ru is not considered.Based on the above results,a quantitative descriptor,E b(one/pl)/E a,in which E a can be further correlated to the d band center of the noble metal catalyst,is proposed by the first time to roughly evaluate and predict the selectivity to cyclohexanone for catalyst screening.展开更多
The photocatalytic performance of g-C_(3)N_(4) for CO_(2) conversion is still inadequate by several shortfalls including the instability,insu cient solar light absorption and rapid charge carrier's recombination r...The photocatalytic performance of g-C_(3)N_(4) for CO_(2) conversion is still inadequate by several shortfalls including the instability,insu cient solar light absorption and rapid charge carrier's recombination rate. To solve these problems,herein,noble metals(Pt and Au)decorated Sr-incorporated g-C_(3)N_(4) photocatalysts are fabricated via the simple calcination and photo-deposition methods. The Sr-incorporation remarkably reduced the g-C_(3)N_(4) band gap from 2.7 to 2.54 eV,as evidenced by the UV–visible absorption spectra and the density functional theory results. The CO_(2) conversion performance of the catalysts was evaluated under visible light irradiation. The Pt/0.15 Sr-CN sample produced 48.55 and 74.54 μmol h-1 g-1 of CH_(4) and CO,respectively.These amounts are far greater than that produced by the Au/0.15 Sr-CN,0.15 Sr-CN,and CN samples. A high quantum e ciency of 2.92% is predicted for the Pt/0.15 Sr-CN sample. Further,the stability of the photocatalyst is confirmed via the photocatalytic recyclable test. The improved CO_(2) conversion performance of the catalyst is accredited to the promoted light absorption and remarkably enhanced charge separation via the Sr-incorporated mid gap states and the localized surface plasmon resonance e ect induced by noble metal nanoparticles.This work will provide a new approach for promoting the catalytic e ciency of g-C_(3)N_(4) for e cient solar fuel production.展开更多
In the harmonic approximation, the atomic force constants are derived and the phonon dispersion curves along four major symmetry directions [00ζ], [0ζζ], [ζζζ] and [0ζ1] (or △∑, A and Z in group-theory nota...In the harmonic approximation, the atomic force constants are derived and the phonon dispersion curves along four major symmetry directions [00ζ], [0ζζ], [ζζζ] and [0ζ1] (or △∑, A and Z in group-theory notation) are calculated for four noble metals Cu, Ag, Au and Pt by combining the modified analytic embedded atom method (MAEAM) with the theory of lattice dynamics. A good agreement between calculations and measurements, especially for lower frequencies, shows that the MAEAM provides a reasonable description of lattice dynamics in noble metals.展开更多
Nanomaterials are materials in which at least one of the dimensions of the particles is 100 nm and below.There are many types of nanomaterials,but noble metal nanoparticles are of interest due to their uniquely large ...Nanomaterials are materials in which at least one of the dimensions of the particles is 100 nm and below.There are many types of nanomaterials,but noble metal nanoparticles are of interest due to their uniquely large surface-to-volume ratio,high surface area,optical and electronic properties,high stability,easy synthesis,and tunable surface functionalization.More importantly,noble metal nanoparticles are known to have excellent compatibility with bio-materials,which is why they are widely used in biological applications.The synthesis method of noble metal nanoparticles conventionally involves the reduction of the noble metal salt precursor by toxic reaction agents such as NaBH4,hydrazine,and formaldehyde.This is a major drawback for researchers involved in biological application researches.Hence,the bio-synthesis of noble metal nanoparticles(NPs)by bio-materials via bio-reduction provides an alternative method to synthesize noble metal nanoparticles which are potentially non-toxic and safer for biological application.In this review,the bio-synthesis of noble metal nanoparticle including gold nanoparticle(AuNPs),silver nanoparticle(AgNPs),platinum nanoparticle(PtNPs),and palladium nanoparticle(PdNPs)are first discussed.This is followed by a discussion of these biosynthesized noble metal in biological applications including antimicrobial,wound healing,anticancer drug,and bioimaging.Based on these,it can be concluded that the study on bio-synthesized noble metal nanoparticles will expand further involving bio-reduction by unexplored bio-materials.However,many questions remain on the feasibility of bio-synthesized noble metal nanoparticles to replace existing methods on various biological applications.Nevertheless,the current development of the biological application by bio-synthesized noble metal NPs is still intensively ongoing,and will eventually reach the goal of full commercialization.展开更多
To maximize the catalytic performance of MoS_(2) in the hydrogen evolution reaction,we investigate the electrocatalytic and photocatalytic performance of monolayer MoS_(2) doped with noble metal(Ag,Au,Cu,Pd,and Pt)usi...To maximize the catalytic performance of MoS_(2) in the hydrogen evolution reaction,we investigate the electrocatalytic and photocatalytic performance of monolayer MoS_(2) doped with noble metal(Ag,Au,Cu,Pd,and Pt)using first principles calculation combined with the climbing image nudged elastic band method.We find the band gap of the monolayer MoS_(2) is reduced significantly by the noble metal doping,which is unfavorable to improving its photocatalytic performance.The optical absorption coefficient shows that the doping does not increase the ability of the monolayer MoS_(2) to absorb visible light.The monolayer MoS_(2) doped with the noble metal is not a potential photocatalyst for the hydrogen evolution reaction because the band edge position of the conduction band minimum is lower than-4.44 eV,the reduction potential of H^(+)/H_(2).Fortunately,the band gap reduction increases the electron transport performance of the monolayer MoS_(2),and the activation energy of water splitting is greatly reduced by the noble metal doping,especially the Pt doping.On the whole,noble metal doping can enhance the electrocatalytic performance of the monolayer MoS_(2).展开更多
It is commonly known that the performance of electrocatalysts is largely influenced by the size,morphology,composition,and crystalline phase of noble metal nanocrystals.However,the limited reserves and high cost of no...It is commonly known that the performance of electrocatalysts is largely influenced by the size,morphology,composition,and crystalline phase of noble metal nanocrystals.However,the limited reserves and high cost of noble metals largely restrict their industrial applications.Along with the development of characterization techniques,theoretical calculations,and advanced material synthesis methods,modulating the electrocatalytic properties of noble metal nanocrystals at the atomic scale(e.g.,monolayer/sub-monolayer,single-atom alloy,ultrafine structure)has been flooding out.Engineering noble metal nanocrystals at the atomic level could not only immensely improve the noble metal atom utilization efficiency and lower the cost,but also boost the catalytic performance.In this review,we summarize the recent advanced progresses of regulating the noble metal nanocrystals at the atomic scale towards energy conversion application.Then,the challenges and perspectives of designing noble metal nanocrystals at the atomic scale in the future are discussed and considered.It is expected that this review will inspire scientists to further study precious metal-based materials for energy-oriented catalysis.展开更多
1.IntroductionRecently Daw and Baskes[1,2]proposed the embedded atom model(EAM)on the basisof quasi-atom concept[3]and density-function theory.It is applicable to the transition met-als as well as the simple metals.It...1.IntroductionRecently Daw and Baskes[1,2]proposed the embedded atom model(EAM)on the basisof quasi-atom concept[3]and density-function theory.It is applicable to the transition met-als as well as the simple metals.It has been widely used in point defect[4],surface[5]andthermal expansion[6].Foiles[7]made the application of the EAM to liquid transition metalsand showed that the EAM also provided a realistic description of the energetics and structure展开更多
Y zeolite supporting noble metal catalysts, as the important industrial catalysts for aromatics hydrogenation, have received increasing attention in recent years. Pd M/Y bimetallic catalysts, where M is non noble meta...Y zeolite supporting noble metal catalysts, as the important industrial catalysts for aromatics hydrogenation, have received increasing attention in recent years. Pd M/Y bimetallic catalysts, where M is non noble metal element, were prepared to investigate the effects of the addition of a second metal. Pd M/Y catalysts were evaluated under the following conditions: H 2 pressure 4.2 MPa, MHSV 4.0 h -1 , sulfur content in feed 3000 μg/g. The microreactor results indicated that the second metal remarkably affects the hydrogenation activity of Pd/Y catalysts. Among them, Cr and W improve the sulfur resistance of Pd/Y, but La, Mn, Mo and Ag make the sulfur resistance worse and the second metals have no evident influence on product selectivity and acidic properties of the catalysts.展开更多
Noble metallic nanocrystals are used in a wide variety of applications,such as catalysis,batteries,and bio-and chemical sensors.Most of the previous studies focus on the preparation of thermodynamically stable nanocry...Noble metallic nanocrystals are used in a wide variety of applications,such as catalysis,batteries,and bio-and chemical sensors.Most of the previous studies focus on the preparation of thermodynamically stable nanocrystals enclosed by low-index facets and discuss their corresponding catalytic properties.Recently,researchers have found that the nanocrystals with high-index facets(HIFs)are of more interest for electrocatalysis.Herein,we review recent key progress in the synthesis of noble metallic nanoparticles enclosed with HIFs and their facetdependent electrocatalytic behaviors.First,we introduce the concept of HIFs,and establish the correlation between their surface structure and catalytic activity.Then,we discuss various synthetic approaches for controlling the shapes and composition of the nanocrystals enclosed by HIFs.Afterwards,we showcase the enhanced electrocatalytic performance realized by HIF-based nanostructures.Finally,we provide guidance on how to improve the electrocatalysis by engineering HIFs on noble metallic nanocrystals.展开更多
This paper reports that an atomic scale study of [^-110] symmetrical tilt grain boundary (STGB) has been made with modified analytical embedded atom method (MAEAM) for 44 planes in three noble metals Au, Ag and Cu...This paper reports that an atomic scale study of [^-110] symmetrical tilt grain boundary (STGB) has been made with modified analytical embedded atom method (MAEAM) for 44 planes in three noble metals Au, Ag and Cu. For each metal, the energies of two crystals ideally joined together are unrealistically hlgh due to very short distance between atoms near the grain boundary (GB) plane. A relative slide between grains in the GB plane results in a significaut decrease in GB energy and a minimum value is obtained at specific translation distance. The minimum energy of Cu is much higher than that of Ag and Au, while the minimum energy of Ag is slightly higher than that of Au. For all the three metals, the three lowest energies correspond to identical (111), (113) and (331) boundary successively for two translations considered; from minimization of GB energy, these boundaries should be preferable in [^-110] STGB for noble metals. This is consistent with the experimental results. In addition, the minimum energy increases with increasing reciprocal planar coincidence density ∑, but decreases with increasing relative interplanar distance d/a.展开更多
A series of alumina supported cobalt oxide based catalysts doped with noble metals such as ruthenium and platinum were prepared by wet impregnation method.The variables studied were difference ratio and calcination te...A series of alumina supported cobalt oxide based catalysts doped with noble metals such as ruthenium and platinum were prepared by wet impregnation method.The variables studied were difference ratio and calcination temperatures.Pt/Co(10∶90)/Al2O3 catalyst calcined at 700 ℃ was found to be the best catalyst which able to convert 70.10% of CO2 into methane with 47% of CH4 formation at maximum temperature studied of 400 ℃.X-ray diffraction analysis showed that this catalyst possessed the active site Co3O4 in face-centered cubic and PtO2 in the orthorhombic phase with Al2O3 existed in the cubic phase.According to the FESEM micrographs,both fresh and spent Pt/Co(10∶90)/Al2O3 catalysts displayed small particle size with undefined shape.Nitrogen Adsorption analysis showed that 5.50% reduction of the total surface area for the spent Pt/Co(10∶90)/Al2O3 catalyst.Meanwhile,Energy Dispersive X-ray analysis(EDX) indicated that Co and Pt were reduced by 0.74% and 0.14% respectively on the spent Pt/Co(10∶90)/Al2O3catalyst.Characterization using FT-IR and TGA-DTA analysis revealed the existence of residual nitrate and hydroxyl compounds on the Pt/Co(10∶90)/Al2O3 catalyst.展开更多
Nanocrystalline In_2O_3 was synthesized through a controllable solvothermal process in one-step at 210℃for 24 h. Gas sensing properties were tested by mixing gas in air in static state.At 268.5℃,the nanocrystal show...Nanocrystalline In_2O_3 was synthesized through a controllable solvothermal process in one-step at 210℃for 24 h. Gas sensing properties were tested by mixing gas in air in static state.At 268.5℃,the nanocrystal showed high sensitivity to LPG but lower sensitivity to H_2 and CO.In order to enhance the sensitivities to H_2 and CO,0.5 mass % Au and Pd were doped by an impregnation process.The sensitivities to H_2 and CO were increased under different working temperature.Au-doped In_2O_3 was superior to Pd-doped In_2O_3 whatever to H_2 or CO;the sensitivity was increased with the increase of working temperature;gas sensing properties to H_2 overmatched to CO.展开更多
It is shown that the ore-forming systems (OFS) of the Vendian-Riphean Greenstone belts (GSB) in the Transbaikalia region were formed in a wide age range: from the Riphean to the Cenozoic. They are grouped into 6 metal...It is shown that the ore-forming systems (OFS) of the Vendian-Riphean Greenstone belts (GSB) in the Transbaikalia region were formed in a wide age range: from the Riphean to the Cenozoic. They are grouped into 6 metallogenic types. The noble metal type is divided into 6 metallogenic subtypes differed in time duration intervals of functioning. OFS evolution wore multistage nature inherited from the composition of the GSB primary rocks, with a tendency of the ore generating processes remobilization and regeneration (dynamometamorphism) changing over time by rejuvenation (shoshonite latite and picrobasalt magmatism, mud volcanism).展开更多
Aluminas supported noble metal nanoparticles have been synthesized by a new ionothermal process. The method used is easy to implement and allows obtaining catalysts in one step with high specific surface area. In addi...Aluminas supported noble metal nanoparticles have been synthesized by a new ionothermal process. The method used is easy to implement and allows obtaining catalysts in one step with high specific surface area. In addition, the metallic phase in the composites is highly dispersed and exhibits homogeneous size.展开更多
Breakage of the C-N bond is a structure sensitive process,and the catalyst size significantly affects its activity.On the active metal nanoparticle scale,the role of catalyst size in C-N bond cleavage has not been cle...Breakage of the C-N bond is a structure sensitive process,and the catalyst size significantly affects its activity.On the active metal nanoparticle scale,the role of catalyst size in C-N bond cleavage has not been clearly elucidated.So,Ru catalysts with variable nanoparticle sizes were obtained by modulating the reduction temperature,and the catalytic activity was evaluated using 1,2,3,4-tetrahydroquinoline and o-propylaniline with different C-N bond hybridization patterns as reactants.Results showed a 13 times higher reaction rate for sp3-hybridized C-N bond cleavage than sp2-hybridized C-N bond cleavage,while the reaction rate tended to increase first and then decrease as the catalyst nanoparticle size increased.Different concentrations of terrace,step,and corner sites were found in different sizes of Ru nanoparticles.The relationship between catalytic site variation and C-N bond cleavage activity was further investigated by calculating the turnover frequency values for each site.This analysis indicates that the variation of different sites on the catalyst is the intrinsic factor of the size dependence of C-N bond cleavage activity,and the step atoms are the active sites for the C-N bond cleavage.When Ru nanoparticles are smaller than 1.9 nm,they have a strong adsorption effect on the reactants,which will affect the catalytic performance of the Ru catalyst.Furthermore,these findings were also confirmed on other metallic Pd/Pt catalysts.The role of step sites in C-N bond cleavage was proposed using the density function theory calculations.The reactants have stronger adsorption energies on the step atoms,and step atoms have d-band center nearer to the Fermi level.In this case,the interaction with the reactant is stronger,which is beneficial for activating the C-N bond of the reactant.展开更多
Lithium-oxygen(Li-O_(2)) batteries are considered as the next generation for energy storages systems due to the higher theoretical energy density than that of Li-ion batteries. However, the high charge overpotential c...Lithium-oxygen(Li-O_(2)) batteries are considered as the next generation for energy storages systems due to the higher theoretical energy density than that of Li-ion batteries. However, the high charge overpotential caused by the insulated Li_(2)O_(2)results in low energy efficiency, side reaction from electrolyte and cathode, and therefore poor battery performance. Designing noble metal-based catalysts can be an effective strategy to develop high-performance Li-O_(2)batteries with low charge overpotentials and outstanding cycle stability. However, the charge mechanism for noble metal-based catalysts is not clear and even contradictory. Herein, several charge mechanisms of Li_(2)O_(2)are first discussed. Subsequently, the possible charge processes of Li-O_(2)batteries with noble metal-based catalysts are illustrated. In addition, the future development for noble metal-based catalysts is outlined.展开更多
基金supported by the National Natural Science Foundation of China(22374119,21902128)the China Postdoctoral Science Foundation(2021M692620)+1 种基金the Research Fund of the State Key Laboratory of Solidification Processing(NPU),China(2021-QZ-01)the Key Project of Natural Science Fund of Shaanxi Province(2023-JC-ZD-06)。
文摘The sluggish kinetics of the oxygen reduction reaction(ORR)is the bottleneck for various electrochemical energy conversion devices.Regulating the electronic structure of electrocatalysts by ligands has received particular attention in deriving valid ORR electrocatalysts.Here,the surface electronic structure of Ptbased noble metal aerogels(NMAs)was modulated by various organic ligands,among which the electron-withdrawing ligand of 4-methylphenylene effectively boosted the ORR electrocatalysis.Theoretical calculations suggested the smaller energy barrier for the transformation of O^(*) to OH^(*) and downshift the d-band center of Pt due to the interaction between 4-methylphenylene and the surface metals,thus enhancing the ORR intrinsic activity.Both Pt3Ni and Pt Pd aerogels with 4-methylphenylene decoration performed significant enhancement in ORR activity and durability in different media.Remarkably,the 4-methylphenylene modified Pt Pd aerogel exhibited the higher halfwave potential of 0.952 V and the mass activity of 10.2 times of commercial Pt/C.This work explained the effect of electronic structure on ORR electrocatalytic properties and would promote functionalized NMAs as efficient ORR electrocatalysts.
基金This work was supported by the Fundamental Research Funds for the Central Universities(No.2022XJHH02)the National Key Research and Development Program of China(No.2019YFC1907602).
文摘The exploitation of electrocatalysts with high activity and durability for HER is desirable for future energy systems,but it is still a challenge.NMPs have attracted increasing attentions,but the preparation process often needs toxic regents or dangerous reaction conditions.Herein,we develop a general green method to fabricate metal-rich NMPs anchored on NPG through pyrolyzing DNA cross-linked complexes.The obtained Ru_(2) P-NPG exhibits an ultrasmall overpotential of 7 mV at 10 mA cm^(2) and ultralow Tafel slope of 33 mV dec^(-1) in 1.0 mol L?1 KOH,even better than that of commercial Pt/C.In addition,Ru 2 P-NPG also shows low overpotentials of 29 and 78 mV in 0.5 mol L^(-1) H_(2)SO_(4) and 1.0 mol L^(-1) PBS,respectively.The superior activity can be attributed to the ultrafine dispersion of Ru 2 P nanoparticles for more accessible sites,more defects formed for abundant active sites,the two-dimensional plane structure for accelerated electron transfer and mass transport,as well as the regulation of electron distribution of the catalyst.Moreover,the synthetic method can also be applied to prepare other metal-rich noble metal phosphides(Pd_(3)P-NPG and Rh_(2)P-NPG),which also exhibits high activity for HER.This work provides an effective strategy for designing NMP-based electrocatalysts.
基金supported by the National Key R&D Program of China(No.2020YFB2008604,2021YFB3202500)the National Natural Science Foundation of China(No.61874034)the International Science and Technology Cooperation Program of Shanghai Science and Technology Innovation Action Plan(No.21520713300)。
文摘Highly sensitive gas sensors with remarkably low detection limits are attractive for diverse practical application fields including real-time environmental monitoring,exhaled breath diagnosis,and food freshness analysis.Among various chemiresistive sensing materials,noble metal-decorated semiconducting metal oxides(SMOs)have currently aroused extensive attention by virtue of the unique electronic and catalytic properties of noble metals.This review highlights the research progress on the designs and applications of different noble metal-decorated SMOs with diverse nanostructures(e.g.,nanoparticles,nanowires,nanorods,nanosheets,nanoflowers,and microspheres)for high-performance gas sensors with higher response,faster response/recovery speed,lower operating temperature,and ultra-low detection limits.The key topics include Pt,Pd,Au,other noble metals(e.g.,Ag,Ru,and Rh.),and bimetals-decorated SMOs containing ZnO,SnO_(2),WO_(3),other SMOs(e.g.,In_(2)O_(3),Fe_(2)O_(3),and CuO),and heterostructured SMOs.In addition to conventional devices,the innovative applications like photo-assisted room temperature gas sensors and mechanically flexible smart wearable devices are also discussed.Moreover,the relevant mechanisms for the sensing performance improvement caused by noble metal decoration,including the electronic sensitization effect and the chemical sensitization effect,have also been summarized in detail.Finally,major challenges and future perspectives towards noble metal-decorated SMOs-based chemiresistive gas sensors are proposed.
基金supported by the National Natural Science Foundation of China(21902097,21636006 and 21761132025)the China Postdoctoral Science Foundation(2019M653861XB)+1 种基金the Natural Science Foundation of Shaanxi Province(2020JQ-409)the Fundamental Research Funds for the Central Universities(GK201901001 and GK202003035)。
文摘Oxidative dehydrogenation of propane with carbon dioxide(CO_(2)-ODP)characterizes the tandem dehydrogenation of propane to propylene with the reduction of the greenhouse gas of CO_(2)to valuable CO.However,the existing catalyst is limited due to the poor activity and stability,which hinders its industrialization.Herein,we design the finned Zn-MFI zeolite encapsulated noble metal nanoparticles(NPs)as bifunctional catalysts(NPs@Zn-MFI)for CO_(2)-ODP.Characterization results reveal that the Zn2+species are coordinated with the MFI zeolite matrix as isolated cations and the NPs of Pt,Rh,or Rh Pt are highly dispersed in the zeolite crystals.The isolated Zn2+cations are very effective for activating the propane and the small NPs are favorable for activating the CO_(2),which synergistically promote the selective transformation of propane and CO_(2)to propylene and CO.As a result,the optimal 0.25%Rh0.50%Pt@Zn-MFI catalyst shows the best propylene yield,satisfactory CO_(2)conversion,and long-term stability.Moreover,considering the tunable synergetic effects between the isolated cations and NPs,the developed approach offers a general guideline to design more efficient CO_(2)-ODP catalysts,which is validated by the improved performance of the bifunctional catalysts via simply substituting Sn4+cations for Zn2+cations in the MFI zeolite matrix.
基金This work was supported by Financial support from the National Natural Science Foundation of China(21908189,21872121)the National Key R&D Program of China(2016YFA0202900)+1 种基金the Key Program supportedby theNaturalScience Foundationof ZhejiangProvince,China(LZ18B060002)the Key R&D Project of Zhejiang Province(2020C01133).
文摘Selective hydrogenation of phenol to cyclohexanone is intriguing in chemical industry.Though a few catalysts with promising performances have been developed in recent years,the basic principle for catalyst design is still missing owing to the unclear catalytic mechanism.This work tries to unravel the mechanism of phenol hydro-genation and the reasons causing the selectivity discrepancy on noble metal catalysts under mild conditions.Results show that different reaction pathways always firstly converge to the formation of cyclohexanone under mild conditions.The selectivity discrepancy mainly depends on the activity for cyclohexanone sequential hy-drogenation,in which two factors are found to be responsible,i.e.the hydrogenation energy barrier and the competitive chemisorption between phenol and cyclohexanone,if the specific co-catalyzing effect of H 2 O on Ru is not considered.Based on the above results,a quantitative descriptor,E b(one/pl)/E a,in which E a can be further correlated to the d band center of the noble metal catalyst,is proposed by the first time to roughly evaluate and predict the selectivity to cyclohexanone for catalyst screening.
基金financially supported by the Ministry of Science and Technology of China (Grant No. 2018YFA0702100)the National Natural Science Foundation of China (Grant No. 11874169,51972129)+4 种基金the National Key R&D Program of China (Grant No. 2017YFE0120500)the Key Research and Development Program of Hubei (Grant No. 2020BAB079)the South Xinjiang Innovation and Development Program of Key Industries of Xinjiang Production and Construction Corps (Grants No. 2020DB002)Engineering and Physical Sciences Research Council (EP/T025875/1)the Hubei “ChuTian Young Scholar” program。
文摘The photocatalytic performance of g-C_(3)N_(4) for CO_(2) conversion is still inadequate by several shortfalls including the instability,insu cient solar light absorption and rapid charge carrier's recombination rate. To solve these problems,herein,noble metals(Pt and Au)decorated Sr-incorporated g-C_(3)N_(4) photocatalysts are fabricated via the simple calcination and photo-deposition methods. The Sr-incorporation remarkably reduced the g-C_(3)N_(4) band gap from 2.7 to 2.54 eV,as evidenced by the UV–visible absorption spectra and the density functional theory results. The CO_(2) conversion performance of the catalysts was evaluated under visible light irradiation. The Pt/0.15 Sr-CN sample produced 48.55 and 74.54 μmol h-1 g-1 of CH_(4) and CO,respectively.These amounts are far greater than that produced by the Au/0.15 Sr-CN,0.15 Sr-CN,and CN samples. A high quantum e ciency of 2.92% is predicted for the Pt/0.15 Sr-CN sample. Further,the stability of the photocatalyst is confirmed via the photocatalytic recyclable test. The improved CO_(2) conversion performance of the catalyst is accredited to the promoted light absorption and remarkably enhanced charge separation via the Sr-incorporated mid gap states and the localized surface plasmon resonance e ect induced by noble metal nanoparticles.This work will provide a new approach for promoting the catalytic e ciency of g-C_(3)N_(4) for e cient solar fuel production.
基金Project supported by the State Key Program of Basic Research of China (Grant No 2004CB619302) and the National Natural Science Foundation of China (Grant No 50271038).
文摘In the harmonic approximation, the atomic force constants are derived and the phonon dispersion curves along four major symmetry directions [00ζ], [0ζζ], [ζζζ] and [0ζ1] (or △∑, A and Z in group-theory notation) are calculated for four noble metals Cu, Ag, Au and Pt by combining the modified analytic embedded atom method (MAEAM) with the theory of lattice dynamics. A good agreement between calculations and measurements, especially for lower frequencies, shows that the MAEAM provides a reasonable description of lattice dynamics in noble metals.
基金This work was financially supported by the National Natural Science Foundation of China(No.21536010).
文摘Nanomaterials are materials in which at least one of the dimensions of the particles is 100 nm and below.There are many types of nanomaterials,but noble metal nanoparticles are of interest due to their uniquely large surface-to-volume ratio,high surface area,optical and electronic properties,high stability,easy synthesis,and tunable surface functionalization.More importantly,noble metal nanoparticles are known to have excellent compatibility with bio-materials,which is why they are widely used in biological applications.The synthesis method of noble metal nanoparticles conventionally involves the reduction of the noble metal salt precursor by toxic reaction agents such as NaBH4,hydrazine,and formaldehyde.This is a major drawback for researchers involved in biological application researches.Hence,the bio-synthesis of noble metal nanoparticles(NPs)by bio-materials via bio-reduction provides an alternative method to synthesize noble metal nanoparticles which are potentially non-toxic and safer for biological application.In this review,the bio-synthesis of noble metal nanoparticle including gold nanoparticle(AuNPs),silver nanoparticle(AgNPs),platinum nanoparticle(PtNPs),and palladium nanoparticle(PdNPs)are first discussed.This is followed by a discussion of these biosynthesized noble metal in biological applications including antimicrobial,wound healing,anticancer drug,and bioimaging.Based on these,it can be concluded that the study on bio-synthesized noble metal nanoparticles will expand further involving bio-reduction by unexplored bio-materials.However,many questions remain on the feasibility of bio-synthesized noble metal nanoparticles to replace existing methods on various biological applications.Nevertheless,the current development of the biological application by bio-synthesized noble metal NPs is still intensively ongoing,and will eventually reach the goal of full commercialization.
基金the Joint Funds of the National Natural Science Foundation of China(Grant No.U1967212)the National Science and Technology Major Project of China(Grant No.2019XS06004009)the Fundamental Research Funds for the Central Universities(Grant No.2018ZD10).
文摘To maximize the catalytic performance of MoS_(2) in the hydrogen evolution reaction,we investigate the electrocatalytic and photocatalytic performance of monolayer MoS_(2) doped with noble metal(Ag,Au,Cu,Pd,and Pt)using first principles calculation combined with the climbing image nudged elastic band method.We find the band gap of the monolayer MoS_(2) is reduced significantly by the noble metal doping,which is unfavorable to improving its photocatalytic performance.The optical absorption coefficient shows that the doping does not increase the ability of the monolayer MoS_(2) to absorb visible light.The monolayer MoS_(2) doped with the noble metal is not a potential photocatalyst for the hydrogen evolution reaction because the band edge position of the conduction band minimum is lower than-4.44 eV,the reduction potential of H^(+)/H_(2).Fortunately,the band gap reduction increases the electron transport performance of the monolayer MoS_(2),and the activation energy of water splitting is greatly reduced by the noble metal doping,especially the Pt doping.On the whole,noble metal doping can enhance the electrocatalytic performance of the monolayer MoS_(2).
基金supported by the National Key R&D Program of China 2017YFA(0208300,0700104)the National Natural Science Foundation of China(21522107,21671180)+1 种基金the DNL Cooperation Fund,CAS(NDL201918)the China Postdoctoral Science Foundation(2019TQ0295,2019M662165)。
文摘It is commonly known that the performance of electrocatalysts is largely influenced by the size,morphology,composition,and crystalline phase of noble metal nanocrystals.However,the limited reserves and high cost of noble metals largely restrict their industrial applications.Along with the development of characterization techniques,theoretical calculations,and advanced material synthesis methods,modulating the electrocatalytic properties of noble metal nanocrystals at the atomic scale(e.g.,monolayer/sub-monolayer,single-atom alloy,ultrafine structure)has been flooding out.Engineering noble metal nanocrystals at the atomic level could not only immensely improve the noble metal atom utilization efficiency and lower the cost,but also boost the catalytic performance.In this review,we summarize the recent advanced progresses of regulating the noble metal nanocrystals at the atomic scale towards energy conversion application.Then,the challenges and perspectives of designing noble metal nanocrystals at the atomic scale in the future are discussed and considered.It is expected that this review will inspire scientists to further study precious metal-based materials for energy-oriented catalysis.
文摘1.IntroductionRecently Daw and Baskes[1,2]proposed the embedded atom model(EAM)on the basisof quasi-atom concept[3]and density-function theory.It is applicable to the transition met-als as well as the simple metals.It has been widely used in point defect[4],surface[5]andthermal expansion[6].Foiles[7]made the application of the EAM to liquid transition metalsand showed that the EAM also provided a realistic description of the energetics and structure
文摘Y zeolite supporting noble metal catalysts, as the important industrial catalysts for aromatics hydrogenation, have received increasing attention in recent years. Pd M/Y bimetallic catalysts, where M is non noble metal element, were prepared to investigate the effects of the addition of a second metal. Pd M/Y catalysts were evaluated under the following conditions: H 2 pressure 4.2 MPa, MHSV 4.0 h -1 , sulfur content in feed 3000 μg/g. The microreactor results indicated that the second metal remarkably affects the hydrogenation activity of Pd/Y catalysts. Among them, Cr and W improve the sulfur resistance of Pd/Y, but La, Mn, Mo and Ag make the sulfur resistance worse and the second metals have no evident influence on product selectivity and acidic properties of the catalysts.
基金This work was financially supported by the Beijing Natural Science Foundation(JQ18005)the National Natural Science Foundation of China(NSFC)(No.51671003)+2 种基金National Basic Research Program of China(No.2016YFB0100201)the China Postdoctoral Science Foundation(No.2017M620518)Open Project Foundation of State Key Laboratory of Chemical Resource Engineering,the start-up supports from Peking University and Young Thousand Talented Program.
文摘Noble metallic nanocrystals are used in a wide variety of applications,such as catalysis,batteries,and bio-and chemical sensors.Most of the previous studies focus on the preparation of thermodynamically stable nanocrystals enclosed by low-index facets and discuss their corresponding catalytic properties.Recently,researchers have found that the nanocrystals with high-index facets(HIFs)are of more interest for electrocatalysis.Herein,we review recent key progress in the synthesis of noble metallic nanoparticles enclosed with HIFs and their facetdependent electrocatalytic behaviors.First,we introduce the concept of HIFs,and establish the correlation between their surface structure and catalytic activity.Then,we discuss various synthetic approaches for controlling the shapes and composition of the nanocrystals enclosed by HIFs.Afterwards,we showcase the enhanced electrocatalytic performance realized by HIF-based nanostructures.Finally,we provide guidance on how to improve the electrocatalysis by engineering HIFs on noble metallic nanocrystals.
基金Project supported by the State Key Development for Basic Research of China (Grant No 2004CB619302) and the National Natural Science Foundation of China (Grant No 50271038).
文摘This paper reports that an atomic scale study of [^-110] symmetrical tilt grain boundary (STGB) has been made with modified analytical embedded atom method (MAEAM) for 44 planes in three noble metals Au, Ag and Cu. For each metal, the energies of two crystals ideally joined together are unrealistically hlgh due to very short distance between atoms near the grain boundary (GB) plane. A relative slide between grains in the GB plane results in a significaut decrease in GB energy and a minimum value is obtained at specific translation distance. The minimum energy of Cu is much higher than that of Ag and Au, while the minimum energy of Ag is slightly higher than that of Au. For all the three metals, the three lowest energies correspond to identical (111), (113) and (331) boundary successively for two translations considered; from minimization of GB energy, these boundaries should be preferable in [^-110] STGB for noble metals. This is consistent with the experimental results. In addition, the minimum energy increases with increasing reciprocal planar coincidence density ∑, but decreases with increasing relative interplanar distance d/a.
文摘A series of alumina supported cobalt oxide based catalysts doped with noble metals such as ruthenium and platinum were prepared by wet impregnation method.The variables studied were difference ratio and calcination temperatures.Pt/Co(10∶90)/Al2O3 catalyst calcined at 700 ℃ was found to be the best catalyst which able to convert 70.10% of CO2 into methane with 47% of CH4 formation at maximum temperature studied of 400 ℃.X-ray diffraction analysis showed that this catalyst possessed the active site Co3O4 in face-centered cubic and PtO2 in the orthorhombic phase with Al2O3 existed in the cubic phase.According to the FESEM micrographs,both fresh and spent Pt/Co(10∶90)/Al2O3 catalysts displayed small particle size with undefined shape.Nitrogen Adsorption analysis showed that 5.50% reduction of the total surface area for the spent Pt/Co(10∶90)/Al2O3 catalyst.Meanwhile,Energy Dispersive X-ray analysis(EDX) indicated that Co and Pt were reduced by 0.74% and 0.14% respectively on the spent Pt/Co(10∶90)/Al2O3catalyst.Characterization using FT-IR and TGA-DTA analysis revealed the existence of residual nitrate and hydroxyl compounds on the Pt/Co(10∶90)/Al2O3 catalyst.
文摘Nanocrystalline In_2O_3 was synthesized through a controllable solvothermal process in one-step at 210℃for 24 h. Gas sensing properties were tested by mixing gas in air in static state.At 268.5℃,the nanocrystal showed high sensitivity to LPG but lower sensitivity to H_2 and CO.In order to enhance the sensitivities to H_2 and CO,0.5 mass % Au and Pd were doped by an impregnation process.The sensitivities to H_2 and CO were increased under different working temperature.Au-doped In_2O_3 was superior to Pd-doped In_2O_3 whatever to H_2 or CO;the sensitivity was increased with the increase of working temperature;gas sensing properties to H_2 overmatched to CO.
文摘It is shown that the ore-forming systems (OFS) of the Vendian-Riphean Greenstone belts (GSB) in the Transbaikalia region were formed in a wide age range: from the Riphean to the Cenozoic. They are grouped into 6 metallogenic types. The noble metal type is divided into 6 metallogenic subtypes differed in time duration intervals of functioning. OFS evolution wore multistage nature inherited from the composition of the GSB primary rocks, with a tendency of the ore generating processes remobilization and regeneration (dynamometamorphism) changing over time by rejuvenation (shoshonite latite and picrobasalt magmatism, mud volcanism).
文摘Aluminas supported noble metal nanoparticles have been synthesized by a new ionothermal process. The method used is easy to implement and allows obtaining catalysts in one step with high specific surface area. In addition, the metallic phase in the composites is highly dispersed and exhibits homogeneous size.
基金supported by the Key Project of National Natural Science Foundation of China(Grant No.22038008)the Science and Technology Innovation Project of National Energy Group China Shenhua Coal to Oil Chemical Co.(Grant No.MZYHG-2021-01).
文摘Breakage of the C-N bond is a structure sensitive process,and the catalyst size significantly affects its activity.On the active metal nanoparticle scale,the role of catalyst size in C-N bond cleavage has not been clearly elucidated.So,Ru catalysts with variable nanoparticle sizes were obtained by modulating the reduction temperature,and the catalytic activity was evaluated using 1,2,3,4-tetrahydroquinoline and o-propylaniline with different C-N bond hybridization patterns as reactants.Results showed a 13 times higher reaction rate for sp3-hybridized C-N bond cleavage than sp2-hybridized C-N bond cleavage,while the reaction rate tended to increase first and then decrease as the catalyst nanoparticle size increased.Different concentrations of terrace,step,and corner sites were found in different sizes of Ru nanoparticles.The relationship between catalytic site variation and C-N bond cleavage activity was further investigated by calculating the turnover frequency values for each site.This analysis indicates that the variation of different sites on the catalyst is the intrinsic factor of the size dependence of C-N bond cleavage activity,and the step atoms are the active sites for the C-N bond cleavage.When Ru nanoparticles are smaller than 1.9 nm,they have a strong adsorption effect on the reactants,which will affect the catalytic performance of the Ru catalyst.Furthermore,these findings were also confirmed on other metallic Pd/Pt catalysts.The role of step sites in C-N bond cleavage was proposed using the density function theory calculations.The reactants have stronger adsorption energies on the step atoms,and step atoms have d-band center nearer to the Fermi level.In this case,the interaction with the reactant is stronger,which is beneficial for activating the C-N bond of the reactant.
基金the financial support from the National Natural Science Foundation of China (No. 12175098)Hundred Talents Sailing Project of Jiangxi Province, China。
文摘Lithium-oxygen(Li-O_(2)) batteries are considered as the next generation for energy storages systems due to the higher theoretical energy density than that of Li-ion batteries. However, the high charge overpotential caused by the insulated Li_(2)O_(2)results in low energy efficiency, side reaction from electrolyte and cathode, and therefore poor battery performance. Designing noble metal-based catalysts can be an effective strategy to develop high-performance Li-O_(2)batteries with low charge overpotentials and outstanding cycle stability. However, the charge mechanism for noble metal-based catalysts is not clear and even contradictory. Herein, several charge mechanisms of Li_(2)O_(2)are first discussed. Subsequently, the possible charge processes of Li-O_(2)batteries with noble metal-based catalysts are illustrated. In addition, the future development for noble metal-based catalysts is outlined.