Mesoporous carbon(MC) with surface area of 380 m^2/g was prepared and employed as the carbon support of Pt catalyst for counter electrode of dye-sensitized solar cells.Pt/MC samples containing 1 wt%Pt were prepared ...Mesoporous carbon(MC) with surface area of 380 m^2/g was prepared and employed as the carbon support of Pt catalyst for counter electrode of dye-sensitized solar cells.Pt/MC samples containing 1 wt%Pt were prepared by reducing chloroplatinic acid on MC using wet impregnation.It was found that Pt nanoparticles were uniform in size and highly dispersed on MC supports.The average size of Pt nanoparticles is about 3.4 nm.Pt/MC electrodes were fabricated by coating Pt/MC samples on fluorine-doped tin oxide glass.The overall conversion efficiency of dye-sensitized solar cells with Pt/MC counter electrode is 6.62%,which is higher than that of the cells with conventional Pt counter electrode in the same conditions.展开更多
Nafion-stabilized Pt nanoparticle colloidal solution is synthesized through ethylene glycol reduction.Pt/Nafion added with carbon black as electric conduction material(labeled Pt/Nafion-XC72) shows excellent electro...Nafion-stabilized Pt nanoparticle colloidal solution is synthesized through ethylene glycol reduction.Pt/Nafion added with carbon black as electric conduction material(labeled Pt/Nafion-XC72) shows excellent electrochemical property compared with Pt/C.After a 300-cycle discharging durability test,the cell performance of membrane electrode assembly(MEA) with the Pt/Nafion-XC72 and Pt/C catalysts indicates a 29.9% and 92.2% decrease,respectively.The charge transfer resistances of Pt/Nafion-XC72 and Pt/C increase by 27.2% and 101.9%,respectively.The remaining electrochemically active surface area of Pt is about 61.7% in Pt/Nafion-XC72 and about 38.1% in Pt/C after the durability test.The particle size of Pt/C increases from about 5.1 nm to about 10.8 nm but only from 3.6 nm to 5.8 nm in the case of Pt/Nafion-XC72.These data suggest that Pt/Nafion-XC72 as a catalyst can enhance the durability of PEMFCs compared with Pt/C.展开更多
Pt nanoparticles(PtNPs)as active species have always been considered as one of the best semiconductor materials for photocatalytic hydrogen production.In this study,a Schottky heterojunction has been successfully cons...Pt nanoparticles(PtNPs)as active species have always been considered as one of the best semiconductor materials for photocatalytic hydrogen production.In this study,a Schottky heterojunction has been successfully constructed by evenly loading ultrafine PtNPs onto a triazine-based covalent organic frameworks(COFs).This strategy maintained the high activity of these ultra-small PtNPs while maximizing the utilization of the Pt active sites.The fabricated PtNPs@covalent triazine-based framework-1(CTF-1)composite accomplished a significantly high rate of hydrogen evolution(20.0 mmol·g^(−1)·h^(−1),apparent quantum efficiency(AQE)=7.6%,atλ=450 nm)with 0.40 wt.%Pt loading,giving rise to a 44-fold-increase in the efficiency of the photocatalytic hydrogen production compared to the pristine CTF-1.Theoretical calculations revealed that the strong electron transfer(Q(Pt)=−0.726 qe,in the analysis of Bader charge,Q(Pt)is the charge quantity transferred from Pt cluster to CTF-1,and qe is the unit of charge transfer quantity)between PtNPs and CTF-1 triggers a strong interaction,which makes PtNPs being firmly attached to the structure of CTF-1,thereby enabling high stability and excellent hydrogen production efficiency.Importantly,the hydrogen binding free energy(ΔGH*)of PtNPs@CTF-1 is much lower than that of the unmodified CTF-1,leading to a much lower intermediate state and hence a significant improvement in photocatalytic performance.The overall findings of this work provide a new platform to incorporate metallic NPs into COFs for the design and fabrication of highly efficient photocatalysts.展开更多
Three-dimensionally(3D) ordered mesoporous carbon sphere arrays(OMCS) are explored to support high loading(60 wt%) Pt nanoparticles as electrocatalysts for the methanol oxidation reaction(MOR).The OMCS has a u...Three-dimensionally(3D) ordered mesoporous carbon sphere arrays(OMCS) are explored to support high loading(60 wt%) Pt nanoparticles as electrocatalysts for the methanol oxidation reaction(MOR).The OMCS has a unique hierarchical nanostructure with ordered large mesopores and macropores that can facilitate high dispersion of the Pt nanoparticles and fast mass transport during the reactions. The prepared Pt/OMCS exhibits uniformly dispersed Pt nanoparticles with an average size of- 2.0 nm on the mesoporous walls of the carbon spheres. The Pt/OMCS catalyst shows significantly enhanced specific electrochemically active surface area(ECSA)(73.5 m^2g^-1) and electrocatalytic activity(0.69 mA cm^-2)for the MOR compared with the commercial 60 wt% Pt/C catalyst.展开更多
The development of a new-fashioned functional nanomaterial with an outstanding photocatalytic hydrogen evolution reaction(HER)activity under visible-light irradiation is a sustainable and promising strategy to cope wi...The development of a new-fashioned functional nanomaterial with an outstanding photocatalytic hydrogen evolution reaction(HER)activity under visible-light irradiation is a sustainable and promising strategy to cope with the increasingly serious global energy crisis.Herein,an advanced ternary photocatalytic HER catalyst,in which the Pt nanoparticles and Ti_(3)C_(2)T_(x)nanosheets are synchronously anchored on the surface of CdS nanospheres(Ti_(3)C_(2)T_(x)/Pt@CdS),is elaborately constructed via acid etching,sel-freduction,and solvothermal treatment.Therein,the synergistic promoting effect between Ti_(3)C_(2)T_(x)and Pt on the charge transfer of CdS effectively hinders the backtransfer of electrons to recombine with holes,resulting in a high-effective utilization of photoexcited charges.The obtained Ti_(3)C_(2)T_(x)/Pt@CdS possesses a superior photocatalytic HER activity compared to that of single active component catalyst.This work demonstrates the great potential of MXene materials in constructing high performance photocatalysts.展开更多
Pt/WO3/C nanocomposites with parallel WO3 nanorods were synthesized and applied as the cathode catalyst for proton exchange membrane fuel cells (PEMFCs). Electrochemical results and single cell tests show that an en...Pt/WO3/C nanocomposites with parallel WO3 nanorods were synthesized and applied as the cathode catalyst for proton exchange membrane fuel cells (PEMFCs). Electrochemical results and single cell tests show that an enhanced activity for the oxygen reduction reaction (ORR) is obtained for the Pt/WO3/C catalyst compared with Pt/C. The higher catalytic activity might be ascribed to the improved Pt dispersion with smaller particle sizes. The Pt/WO3/C catalyst also exhibits a good electrochemical stability under potential cycling. Thus, the Pt/WO3/C catalyst can be used as a potential PEMFC cathode catalyst.展开更多
Alcohol fuel electro-reforming is promising for green hydrogen generation while developing efficient bifunctional catalysts for alcohol fuel electrolysis is still very tricky.Herein,we for the first time proposed the ...Alcohol fuel electro-reforming is promising for green hydrogen generation while developing efficient bifunctional catalysts for alcohol fuel electrolysis is still very tricky.Herein,we for the first time proposed the electron-enriched Pt induced by CoSe_(2)has an efficient bi-functional catalytic ability for alcohol fuels electro-reforming of hydrogen in acid electrolytes.The theoretical calculation revealed the advantages of electron-enriched Pt surface for the adsorption of intermediate,which is well supported by spectroscopic analysis and CO-stripping techniques.Largely improved catalytic performances of activity,durability,and kinetics are demonstrated compared to the conventional alloy system and commercial Pt/C catalyst,due to the efficient synergism of Pt and CoSe_(2);the peak current density of Pt/CoSe_(2)for methanol(ethanol)oxidation is 87.61(48.27)m A cm^(-2),which is about 3.3(2.0)times higher than that of Pt/C catalyst and 2.0(1.5)times that of the traditional PtCo alloy catalysts.Impressively,about 80%of the initial current was found after 1000 cycles of stability test for alcohol fuel oxidation of Pt/CoSe_(2)catalyst,higher than that of Pt/C(ca.50%)and PtCo catalyst(65%).When Pt/CoSe_(2)catalyst serviced as bi-functional catalysts for electrolyzer,a low cell potential of 0.65(0.78)V for methanol(ethanol)electrolysis was required to reach 10 m A cm^(-2),which was about 1030(900)m V less than that of conventional water electrolysis using Pt/C as the catalyst.The current result is instructive for the design of novel bifunctional catalyst and the understanding of hydrogen generation via alcohol fuel electro-reforming.展开更多
In the electrochemical process,Pt nanoparticles(NPs)in Pt-based catalysts usually agglomerate due to Oswald ripening or lack of restraint,ultimately resulting in reduction of the active sites and catalytic efficiency....In the electrochemical process,Pt nanoparticles(NPs)in Pt-based catalysts usually agglomerate due to Oswald ripening or lack of restraint,ultimately resulting in reduction of the active sites and catalytic efficiency.How to uniformly disperse and firmly fix Pt NPs on carbon matrix with suitable particle size for catalysis is still a big challenge.Herein,to prevent the agglomeration and shedding of Pt NPs,Ni species is introduced and are evenly dispersed in the surface of carbon matrix in the form of Ni-N-C active sites(Ni ZIF-NC).The Ni sites can be used to anchor Pt NPs,and then effectively limit the further growth and agglomeration of Pt NPs during the reaction process.Compared with commercial Pt/C catalyst,Pt@Ni ZIF-NC,with ultralow Pt loading(7 wt%)and ideal particle size(2.3 nm),not only increases the active center,but also promotes the catalysis kinetics,greatly improving the ORR and HER catalytic activity.Under acidic conditions,its half-wave potential(0.902 V)is superior to commercial Pt/C(0.861 V),and the mass activity(0.38 A per mg Pt)at 0.9 V is 4.7 times that of Pt/C(0.08 A per mg Pt).Besides,it also shows outstanding HER performance.At 20 and 30 mV,its mass activity is even 2 and 6 times that of Pt/C,respectively.Whether it is under ORR or HER conditions,it still shows excellent durability.These undoubtedly indicate the realization of dual-functional catalysts with low-Pt and high-efficiency properties.展开更多
Platinum nanoparticles (PtNPs)/graphene composite materials are synthesized by a controlled chemical reduction of H2PtC16 on graphene sheets. The electrocatalytic activity of a PtNPs/graphene composite counter elect...Platinum nanoparticles (PtNPs)/graphene composite materials are synthesized by a controlled chemical reduction of H2PtC16 on graphene sheets. The electrocatalytic activity of a PtNPs/graphene composite counter electrode for a dye-sensitized solar cell (DSSC) is investigated. The results demonstrate that the PtNPs/graphene composite has high electrocatalytic activity for the dye-sensitized solar cell. The cell employing PtNPs (1.6 wt%)/graphene counter electrode reaches an conversion efficiency (η) of 3.89% upon the excitation of 100 mW/cm2 AM 1.5 white light, which is comparable to that of the cell with a Pt-film counter electrode (7 = 3.76%). It suggests that one can use only 14% Pt content of the conventional Pt-film counter electrode to obtain a comparable conversion efficiency. It may be possible to obtain a high performance DSSC using the PtNPs/graphene composite with a very low Pt content as a counter electrode due to its simplicity, low cost, and large scalability.展开更多
Catalytic performance of supported metal catalysts not only depends on the reactivity of metal,but also the adsorption and diffusion properties of gas molecules which are usually affected by many factors,such as tempe...Catalytic performance of supported metal catalysts not only depends on the reactivity of metal,but also the adsorption and diffusion properties of gas molecules which are usually affected by many factors,such as temperature,pressure,properties of metal clusters and substrates,etc.To explore the impact of each of these macroscopic factors,we simulated the movement of CO molecules confined in graphene nanoslits with or without supported Pt nanoparticles.The results of molecular dynamics simulations show that the diffusion of gas molecules is accelerated with high temperature,low pressure or low surface-atom number of supported metals.Notably,the supported metal nanoparticles greatly affect the gas diffusion due to the adsorption of gas molecules.Furthermore,to bridge a quantitative relationship between microscopic simulation and macroscopic properties,a generalized formula is derived from the simulation data to calculate the diffusion coefficient.This work helps to advise the diffusion modulation of gas molecules via structural design of catalysts and regulation of reaction conditions.展开更多
Nanocollision electrochemistry is employed to evaluate the ORR’s activity of one single Pt nanoparticle,the effect of the size and ligand is investigated.The size-normalized activity of the Pt nanoparticle of 4 nm is...Nanocollision electrochemistry is employed to evaluate the ORR’s activity of one single Pt nanoparticle,the effect of the size and ligand is investigated.The size-normalized activity of the Pt nanoparticle of 4 nm is two times higher than that of 25 nm,confirming that the intrinsic activity does depend on the size of the nanoparticles.It is further found that the adsorbed ligand does yield effect on electrocatalysis,and the adsorption strength follows the order of PVP>CTAB>citrate.This work is of significance to understand the nature of the ORR’s electrocatalysis at the level of an individual entity,which makes the structure-activity correlation in a more reliable way.展开更多
Nowadays,water pollution has become more serious,greatly affecting human life and healthy.Electrochemical biosensor,a novel and rapid detection technique,plays an important role in the realtime and trace detection of ...Nowadays,water pollution has become more serious,greatly affecting human life and healthy.Electrochemical biosensor,a novel and rapid detection technique,plays an important role in the realtime and trace detection of water pollutants.However,the stability and sensitivity of electrochemical biosensors remain a great challenge for practical detections in real samples to the strong interferences derived from complex components and coagulation effects.In this work,we reported a novel threedimensional architecture of Prussian blue nanoparticles(PBNPs)/Pt nanoparticles(PtNPs)composite film,using 3 D interweaved carbon nanofibers as a supporting matrix,for the construction of screenprinted microchips-based biosensor.PtNPs with diameters of-2.5 nm was highly dispersed on the carbon nanofibers(CNFs)to build a 3 D skeleton nanostructure through a solvothermal reduction.Subsequently,uniform PBNPs were in-situ self-assembled on this skeleton to construct a 3 D architecture of PB/Pt-CNF composite film.Due to the synergistic effects derived from this special feature,the as-prepared hydroquinone(HQ)biosensor chips can synchronously promote both surface area and conductivity to greatly enhance the electrocatalysis from enzymatic reaction.This biosensor has exhibited a high sensitivity of 220.28μA·L·mmol^(-1)·cm^(-2) with an ultrawide linear range from 2.5μmol·L^(-1) to 1.45 mmol·L^(-1) at a low potential of 0.15 V,as well as the satisfactory reproducibility and usage stability.Besides,its accuracy was also verified in the assays of real water samples.It is highly expected that the 3 D PB/Pt-CNF based screen-printed microchips will have wide applications in dynamic monitoring and early warning of analytes in the various practical fields.展开更多
Photocatalytic upgrading of renewable biomass is a promising way to relieve energy crisis and environmental pollution.However,low photocatalytic efficiency and uncontrollable selectivity still limit its development.He...Photocatalytic upgrading of renewable biomass is a promising way to relieve energy crisis and environmental pollution.However,low photocatalytic efficiency and uncontrollable selectivity still limit its development.Herein,ultrathin SnNb_(2)O_(6)nanosheets with high dispersed Pt nanoparticles(Pt/SN)were successfully developed as an efficient photocatalyst for the precise hydrogenation of furfural(FUR)to furfuryl alcohol(FOL)under visible light irradiation and exhibited the high conversion of FUR(99.9%)with the high selectivity for FOL(99.9%).It was revealed that SN with only 4.1 nm thickness possess good separation ability of photo-generated carriers and abundant surface Lewis acid sites(Nb^(5+))which would selectively chemisorb and activate FUR molecules via the Nb···O=C coordination.Meanwhile,Pt nanoparticles would gather photo-generated electrons for greatly promoting the generation of active H species to support the hydrogenation of FUR to FOL.The synergistic effects between SnNb_(2)O_(6)nanosheets and Pt nanoparticles remarkably facilitate the photocatalytic performance for hydrogenation.This work not only confirms the great potential of ultrathin nanosheet photocatalyst with functional metal sites for precise upgrading of biomass but also provides an in-depth view to understand the surface/interface interaction between reactant molecules and surface sites of a photocatalyst.展开更多
The loading strategy of cocatalysts affects its activity exerting and atom utilization.Here,a novel strategy for loading precious metal(Pt)cocatalysts by means of ultrathin N-doped carbon layer is reported.The strateg...The loading strategy of cocatalysts affects its activity exerting and atom utilization.Here,a novel strategy for loading precious metal(Pt)cocatalysts by means of ultrathin N-doped carbon layer is reported.The strategy is based on a pyrolysis process of predesigned N-containing polymers and Pt complexes on hard-template surface,during which Pt can be reduced by carbon from pyrolysis at high temperatures.Finally,the hollow TiO_(2)composite with stable and dispersed Pt on its inner surface was prepared.It shows an ultrahigh photocatalytic H_(2)production activity as high as 25.7 mmol h^(-1)g^(-1)with methanol as sacrificial regent,and displays an apparent quantum yield as 13.2%.The improved photocatalytic activity and stability can be attributed to the highly dispersed and ultrafine Pt nanoparticles,enhanced interaction between Pt-species and carbon support,fast photo-excited electron transport from the high graphitization degree of NC layers,ample oxygen vacancies/defects,as well as the manipulated local charge distribution of Pt/NC-layer configuration.Additionally,the universality of the proposed strategy was demonstrated by replacing metal sources(such as,Ru and Pd).This work presented a promising strategy for the design and development of novel photocatalysts,which shows a broad application prospect.展开更多
Photo-catalytic oxidation of intracellular nicotinamide adenine dinucleotide(2'-phosphate)(NAD(P)H)has attracted much attention for cancer therapy.However,the general oxygen-dependent mechanism heavily depresses t...Photo-catalytic oxidation of intracellular nicotinamide adenine dinucleotide(2'-phosphate)(NAD(P)H)has attracted much attention for cancer therapy.However,the general oxygen-dependent mechanism heavily depresses the efficacy in hypoxic tumors.To solve this problem,herein platinum nanoparticles(Pt NPs)with catalase-like(CAT-like)and catalytic H_(2)evolution activities were introduced as a powerful assistant to enhance the photo-catalytic NAD(P)H oxidation of Ru1([Ru(phen)2(PIP-OCH_(3))]^(2+),phen=1,10-phenanthroline,PIP-OCH_(3)=2-(4-methoxy phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline)under hypoxic and even oxygen-free conditions.Firstly,Pt NPs can transform the original and in situ formed H_(2)O_(2)once again into O_(2)by the CAT-like activity,thus relieving tumor hypoxia and realizing cyclic utilization(at least in part)of the precious oxygen in hypoxia.Secondly,Pt NPs can also be served as H_(2)evolution catalysts while using Ru1 as the photosensitizer and NAD(P)H as the electron and proton donor.In this process,NAD(P)H is oxidized without the participation of oxygen,which can provide an effective way even under oxygen-free conditions.Via co-encapsulation of Rul and Pt NPs in bovine serum albumin(BSA)with tumor targeting ability,the resultant Ru/Pt@BSA could photo-catalyze intracellular NAD(P)H oxidation under hypoxic conditions(3%O_(2)),and exhibited an efficient and selective anticancer activity both in vitro and in vivo.Our results may provide new sights for efficient and targeted cancer treatment underhypoxic conditions.展开更多
This work reports a facile and efficient seed-mediated method for the synthesis of dendritic platinum (Pt) nanoparticles (NPs) at low temperatures of 55-60 ℃ in water, using L-ascorbic acid as a reducing agent an...This work reports a facile and efficient seed-mediated method for the synthesis of dendritic platinum (Pt) nanoparticles (NPs) at low temperatures of 55-60 ℃ in water, using L-ascorbic acid as a reducing agent and sodium citrate as a capping agent. It is found that the dendritic Pt NPs (10-150 nm) are composed of tiny Pt nanocrystals, which nucleate and grow through the introduced smaller Pt seeds with diameters of 3-5 nm. Further investigation shows that the dendritic Pt nanostructures display excellent catalytic performance in an aqueous-phase aromatic ketone hydrogenation reaction, including: (i) acetophenone conversion rate of 〉 90%, with smaller dendritic Pt NPs (10-46 nm) offering a higher conversion efficiency; (ii) high chemoselectivity toward carbonyl group (90.6%-91.5%), e.g., the selectivity to l-phenylethanol is -90.1% with nearly 100% acetophenone conversion for 10 nm dendritic Pt NPs within 60 rain, under mild reaction conditions (20 ℃, 1.5 bar H2 pressure, and 1.5 tool% catalyst). The high catalytic activity, selectivity and stability of the dendritic Pt nanostructures under the organic solvent-free conditions make them promising for many potential applications in green catalytic conversion of hydrophilic biomass derived compounds.展开更多
Localized surface plasmon resonance(LSPR)effects of nanoscale plasmonic metals/semiconductor composites have been extensively applied into visible light photocatalysis.However,Pt nanoparticles(NPs)with the visible LSP...Localized surface plasmon resonance(LSPR)effects of nanoscale plasmonic metals/semiconductor composites have been extensively applied into visible light photocatalysis.However,Pt nanoparticles(NPs)with the visible LSPR absorption maxima have rarely been used as a photosensitizer to facilitate photocatalytic reactions,especially the photocatalytic overall water splitting(POWS)reaction,presumably because they feature weak light absorption.Herein,we present that the increased plasmonic absorption and local field enhancement can be achieved in the wide visible range by exploiting the simulated and experimental expressions of Pt nanocuboctahedra and Pt cuboctahedra-WO_(3)nanohybrids(Pt-WO3).First,monodisperse Pt cuboctahedra with different sizes,a hierarchical WO_(3)nanoarchitecture composed of radially patterned WO_(3)nanopillars,and Pt-WO_(3)were systematically synthesized.Subsequently,visible plasmonic Pt-WO_(3)photocatalysts were employed in the POWS tests and exhibited the significant activity enhancement in the visible light region.The apparent quantum efficiency(AQE)of greater than 7%within the range of visible light has been achieved for the optimal Pt-WO3.展开更多
Based on the volcanic relationship between catalytic activity and key adsorption energies,Pt-Co alloy materials have been widely studied as cathode oxygen reduction reaction(ORR)catalysts in proton exchange membrane f...Based on the volcanic relationship between catalytic activity and key adsorption energies,Pt-Co alloy materials have been widely studied as cathode oxygen reduction reaction(ORR)catalysts in proton exchange membrane fuel cells(PEMFCs)due to their higher active surface area and adjustable D-band energy levels compared to Pt/C.However,how to balance the alloying degree and ORR performance of Pt-Co catalyst remains a great challenge.Herein,we first synthesized a well-dispersed Pt/Co/C precursor by using a mild dimethylamine borane(DMAB)as the reducing agent.The precursor was calcined at high temperature under H_(2)/Ar mixed gas by a secondary reduction strategy to obtain an ordered Pt_(3)Co intermetallic compound nanoparticle catalyst with a high degree of alloying.The optimization of elec-tronic structure due to Pt-Co alloying and the strong metal-carrier interaction ensure the high kinetic activity of the cell membrane electrode.Additionally,the high degree of graphitization increases the electrical conductivity during the reaction.As a result,the activity and stability of the catalyst were significantly improved,with a half-wave potential as high as 0.87 V,which decreased by only 20 mV after 10000 potential cycles.Single-cell tests further validate the high intrinsic activity of the ordered Pt_(3)Co catalyst with mass activity up to 0.67 A mg_(pt)^(-1),exceeding the United States Department of Energy(US DOE)standard(0.44 A mg_(pt)^(-1)),and a rated power of 5.93 W mg_(pt)^(-1).展开更多
Efficient removal of formaldehyde from indoor environments is of significance for human health.In this work,a typical binary transition metal oxide that could provide various oxidation states,β-NiMoO4,was employed as...Efficient removal of formaldehyde from indoor environments is of significance for human health.In this work,a typical binary transition metal oxide that could provide various oxidation states,β-NiMoO4,was employed as a support to immobilize the active Pt component(Pt/NiMoO4)for catalytic formaldehyde elimination at low ambient temperature(15℃).The results showed that the hydrothermal preparation temperature and time had a noticeable impact on the morphology and catalytic activity of the samples.The catalyst prepared with hydrothermal temperature of 150℃for 4 hr(Pt-150-4)exhibited superior catalytic activity and stability mainly due to its distinctly porous structure,relative abundance of adsorbed surface hydroxyls/water,and high oxidation ability,which resulted from the interaction of Pt with Ni and Mo of the bimetallic NiMoO4 support.Our results might shed light on the rational design of multifunctional catalysts for removal of indoor air pollutants at low ambient temperature.展开更多
The LaCo_(0.94)Pt_(0.06)O_(3) catalyst is reduced under 5% H_(2)/Ar at different temperatures to get Pt/LaCoO_(3) with high catalytic activity for soot oxidation.Transmission electron microscopy(TEM),scanning electron...The LaCo_(0.94)Pt_(0.06)O_(3) catalyst is reduced under 5% H_(2)/Ar at different temperatures to get Pt/LaCoO_(3) with high catalytic activity for soot oxidation.Transmission electron microscopy(TEM),scanning electron microscopy(SEM),X-ray diffraction(XRD),Brunauer-Emmett-Teller method(BET),X-ray photoelectron spectroscopy(XPS),H_(2)-temperature programmed reduction(H_(2)-TPR),O_(2)-temperature programmed desorption(O_(2)-TPD) and thermogravimetric analysis(TGA) were used to study the physicochemical properties of the catalyst.SEM and TEM results indicate that Pt nanoparticles(<10 nm) are grown homogeneously on the surface of the LaCoO_(3) matrix after in-situ reduction.XRD shows that the reduced catalyst has a high symmetrical structure.TGA results indicate that all reduced catalysts exhibit an excellent activity,especially the catalyst reduced at 350℃(T_(10)=338℃,T_(50)=393℃,T_(90)=427℃).And perovskite is the primary active component.According to XPS study,the high symmetrical structure benefits the mobility of oxygen vacancy,and Pt nanoparticles induce the oxygen vacancy to move to its adjacent situation,resulting in more adsorbed oxygen on the surface of the reduced catalyst and increasing the activity.The possible reaction principle is also proposed.展开更多
基金supported by National Natural Science Foundations of China(No.20773082)Shandong Department of Science and Technology(No.2006BS09003).
文摘Mesoporous carbon(MC) with surface area of 380 m^2/g was prepared and employed as the carbon support of Pt catalyst for counter electrode of dye-sensitized solar cells.Pt/MC samples containing 1 wt%Pt were prepared by reducing chloroplatinic acid on MC using wet impregnation.It was found that Pt nanoparticles were uniform in size and highly dispersed on MC supports.The average size of Pt nanoparticles is about 3.4 nm.Pt/MC electrodes were fabricated by coating Pt/MC samples on fluorine-doped tin oxide glass.The overall conversion efficiency of dye-sensitized solar cells with Pt/MC counter electrode is 6.62%,which is higher than that of the cells with conventional Pt counter electrode in the same conditions.
基金supported by the National Basic Research Program of China(973 Program,Grant No.2012CB215500the National High-Tech Research and Development Program of China(863 Plan)(No.2012AA052002)the National Natural Science Foundation of China(No.21406024)
文摘Nafion-stabilized Pt nanoparticle colloidal solution is synthesized through ethylene glycol reduction.Pt/Nafion added with carbon black as electric conduction material(labeled Pt/Nafion-XC72) shows excellent electrochemical property compared with Pt/C.After a 300-cycle discharging durability test,the cell performance of membrane electrode assembly(MEA) with the Pt/Nafion-XC72 and Pt/C catalysts indicates a 29.9% and 92.2% decrease,respectively.The charge transfer resistances of Pt/Nafion-XC72 and Pt/C increase by 27.2% and 101.9%,respectively.The remaining electrochemically active surface area of Pt is about 61.7% in Pt/Nafion-XC72 and about 38.1% in Pt/C after the durability test.The particle size of Pt/C increases from about 5.1 nm to about 10.8 nm but only from 3.6 nm to 5.8 nm in the case of Pt/Nafion-XC72.These data suggest that Pt/Nafion-XC72 as a catalyst can enhance the durability of PEMFCs compared with Pt/C.
基金the National Natural Science Foundation of China(Nos.22271022 and 21701016)the Science and Technology Development Planning of Jilin Province(No.YDZJ202201ZYTS342)+1 种基金the China Scholarship Council(CSC No.201802335014)Partial support from the Robert A.Welch Foundation(B-0027)(S.M.)and Researchers Supporting Program(No.RSP-2024R55)at King Saud University,Riyadh,Saudi Arabia is also acknowledged.
文摘Pt nanoparticles(PtNPs)as active species have always been considered as one of the best semiconductor materials for photocatalytic hydrogen production.In this study,a Schottky heterojunction has been successfully constructed by evenly loading ultrafine PtNPs onto a triazine-based covalent organic frameworks(COFs).This strategy maintained the high activity of these ultra-small PtNPs while maximizing the utilization of the Pt active sites.The fabricated PtNPs@covalent triazine-based framework-1(CTF-1)composite accomplished a significantly high rate of hydrogen evolution(20.0 mmol·g^(−1)·h^(−1),apparent quantum efficiency(AQE)=7.6%,atλ=450 nm)with 0.40 wt.%Pt loading,giving rise to a 44-fold-increase in the efficiency of the photocatalytic hydrogen production compared to the pristine CTF-1.Theoretical calculations revealed that the strong electron transfer(Q(Pt)=−0.726 qe,in the analysis of Bader charge,Q(Pt)is the charge quantity transferred from Pt cluster to CTF-1,and qe is the unit of charge transfer quantity)between PtNPs and CTF-1 triggers a strong interaction,which makes PtNPs being firmly attached to the structure of CTF-1,thereby enabling high stability and excellent hydrogen production efficiency.Importantly,the hydrogen binding free energy(ΔGH*)of PtNPs@CTF-1 is much lower than that of the unmodified CTF-1,leading to a much lower intermediate state and hence a significant improvement in photocatalytic performance.The overall findings of this work provide a new platform to incorporate metallic NPs into COFs for the design and fabrication of highly efficient photocatalysts.
基金financial support from the National Natural Science Foundation of China (No. 51172014)the National 973 Program of China (No. 2009CB219903)the Scientific Innovation Grant for Excellent Young Scientists of Hebei University of Technology (No. 2015001)
文摘Three-dimensionally(3D) ordered mesoporous carbon sphere arrays(OMCS) are explored to support high loading(60 wt%) Pt nanoparticles as electrocatalysts for the methanol oxidation reaction(MOR).The OMCS has a unique hierarchical nanostructure with ordered large mesopores and macropores that can facilitate high dispersion of the Pt nanoparticles and fast mass transport during the reactions. The prepared Pt/OMCS exhibits uniformly dispersed Pt nanoparticles with an average size of- 2.0 nm on the mesoporous walls of the carbon spheres. The Pt/OMCS catalyst shows significantly enhanced specific electrochemically active surface area(ECSA)(73.5 m^2g^-1) and electrocatalytic activity(0.69 mA cm^-2)for the MOR compared with the commercial 60 wt% Pt/C catalyst.
基金supported by the National Natural Science Foundation of China(Grant No.62004143)the Key R&D Program of Hubei Province(Grant No.2022BAA084)+1 种基金the Natural Science Foundation of Hubei Province(Grant No.2021CFB133)the Central Government Guided Local Science and Technology Development Special Fund Project(Grant No.2020ZYYD033)。
文摘The development of a new-fashioned functional nanomaterial with an outstanding photocatalytic hydrogen evolution reaction(HER)activity under visible-light irradiation is a sustainable and promising strategy to cope with the increasingly serious global energy crisis.Herein,an advanced ternary photocatalytic HER catalyst,in which the Pt nanoparticles and Ti_(3)C_(2)T_(x)nanosheets are synchronously anchored on the surface of CdS nanospheres(Ti_(3)C_(2)T_(x)/Pt@CdS),is elaborately constructed via acid etching,sel-freduction,and solvothermal treatment.Therein,the synergistic promoting effect between Ti_(3)C_(2)T_(x)and Pt on the charge transfer of CdS effectively hinders the backtransfer of electrons to recombine with holes,resulting in a high-effective utilization of photoexcited charges.The obtained Ti_(3)C_(2)T_(x)/Pt@CdS possesses a superior photocatalytic HER activity compared to that of single active component catalyst.This work demonstrates the great potential of MXene materials in constructing high performance photocatalysts.
基金financially supported by the National Natural Science Fundation of China(No.51125007)the National Basic Research Program(No.2012CB215500)
文摘Pt/WO3/C nanocomposites with parallel WO3 nanorods were synthesized and applied as the cathode catalyst for proton exchange membrane fuel cells (PEMFCs). Electrochemical results and single cell tests show that an enhanced activity for the oxygen reduction reaction (ORR) is obtained for the Pt/WO3/C catalyst compared with Pt/C. The higher catalytic activity might be ascribed to the improved Pt dispersion with smaller particle sizes. The Pt/WO3/C catalyst also exhibits a good electrochemical stability under potential cycling. Thus, the Pt/WO3/C catalyst can be used as a potential PEMFC cathode catalyst.
基金supported by the National Natural Science Foundation of China(21972124,22102105)a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutionthe support of the Six Talent Peaks Project of Jiangsu Province(XCL-070-2018)。
文摘Alcohol fuel electro-reforming is promising for green hydrogen generation while developing efficient bifunctional catalysts for alcohol fuel electrolysis is still very tricky.Herein,we for the first time proposed the electron-enriched Pt induced by CoSe_(2)has an efficient bi-functional catalytic ability for alcohol fuels electro-reforming of hydrogen in acid electrolytes.The theoretical calculation revealed the advantages of electron-enriched Pt surface for the adsorption of intermediate,which is well supported by spectroscopic analysis and CO-stripping techniques.Largely improved catalytic performances of activity,durability,and kinetics are demonstrated compared to the conventional alloy system and commercial Pt/C catalyst,due to the efficient synergism of Pt and CoSe_(2);the peak current density of Pt/CoSe_(2)for methanol(ethanol)oxidation is 87.61(48.27)m A cm^(-2),which is about 3.3(2.0)times higher than that of Pt/C catalyst and 2.0(1.5)times that of the traditional PtCo alloy catalysts.Impressively,about 80%of the initial current was found after 1000 cycles of stability test for alcohol fuel oxidation of Pt/CoSe_(2)catalyst,higher than that of Pt/C(ca.50%)and PtCo catalyst(65%).When Pt/CoSe_(2)catalyst serviced as bi-functional catalysts for electrolyzer,a low cell potential of 0.65(0.78)V for methanol(ethanol)electrolysis was required to reach 10 m A cm^(-2),which was about 1030(900)m V less than that of conventional water electrolysis using Pt/C as the catalyst.The current result is instructive for the design of novel bifunctional catalyst and the understanding of hydrogen generation via alcohol fuel electro-reforming.
基金supported by the National Natural Science Foundation of China(22075223,51701146)the State Key Laboratory of Advanced Technology for Materials Synthesis and Processing(Wuhan University of Technology)(2021-ZD-4)。
文摘In the electrochemical process,Pt nanoparticles(NPs)in Pt-based catalysts usually agglomerate due to Oswald ripening or lack of restraint,ultimately resulting in reduction of the active sites and catalytic efficiency.How to uniformly disperse and firmly fix Pt NPs on carbon matrix with suitable particle size for catalysis is still a big challenge.Herein,to prevent the agglomeration and shedding of Pt NPs,Ni species is introduced and are evenly dispersed in the surface of carbon matrix in the form of Ni-N-C active sites(Ni ZIF-NC).The Ni sites can be used to anchor Pt NPs,and then effectively limit the further growth and agglomeration of Pt NPs during the reaction process.Compared with commercial Pt/C catalyst,Pt@Ni ZIF-NC,with ultralow Pt loading(7 wt%)and ideal particle size(2.3 nm),not only increases the active center,but also promotes the catalysis kinetics,greatly improving the ORR and HER catalytic activity.Under acidic conditions,its half-wave potential(0.902 V)is superior to commercial Pt/C(0.861 V),and the mass activity(0.38 A per mg Pt)at 0.9 V is 4.7 times that of Pt/C(0.08 A per mg Pt).Besides,it also shows outstanding HER performance.At 20 and 30 mV,its mass activity is even 2 and 6 times that of Pt/C,respectively.Whether it is under ORR or HER conditions,it still shows excellent durability.These undoubtedly indicate the realization of dual-functional catalysts with low-Pt and high-efficiency properties.
基金Project supported by the Program for New Century Excellent Talents in University,China (Grant No. NCET-10-0291)the Fundamental Research Funds for the Central Universities,China (Grant Nos. ZYGX2009X005 and ZYGX2010J031)+1 种基金the Startup Research Project of University of Electronic Science and Technology of China (Grant No.Y02002010301041)the National Natural Science Foundation of China (Grant Nos. 50832007,11074285,and 51202022)
文摘Platinum nanoparticles (PtNPs)/graphene composite materials are synthesized by a controlled chemical reduction of H2PtC16 on graphene sheets. The electrocatalytic activity of a PtNPs/graphene composite counter electrode for a dye-sensitized solar cell (DSSC) is investigated. The results demonstrate that the PtNPs/graphene composite has high electrocatalytic activity for the dye-sensitized solar cell. The cell employing PtNPs (1.6 wt%)/graphene counter electrode reaches an conversion efficiency (η) of 3.89% upon the excitation of 100 mW/cm2 AM 1.5 white light, which is comparable to that of the cell with a Pt-film counter electrode (7 = 3.76%). It suggests that one can use only 14% Pt content of the conventional Pt-film counter electrode to obtain a comparable conversion efficiency. It may be possible to obtain a high performance DSSC using the PtNPs/graphene composite with a very low Pt content as a counter electrode due to its simplicity, low cost, and large scalability.
基金the financial support from the National Natural Science Foundation of China(NSFC-21625604,21878272,91934302 and 21706229)。
文摘Catalytic performance of supported metal catalysts not only depends on the reactivity of metal,but also the adsorption and diffusion properties of gas molecules which are usually affected by many factors,such as temperature,pressure,properties of metal clusters and substrates,etc.To explore the impact of each of these macroscopic factors,we simulated the movement of CO molecules confined in graphene nanoslits with or without supported Pt nanoparticles.The results of molecular dynamics simulations show that the diffusion of gas molecules is accelerated with high temperature,low pressure or low surface-atom number of supported metals.Notably,the supported metal nanoparticles greatly affect the gas diffusion due to the adsorption of gas molecules.Furthermore,to bridge a quantitative relationship between microscopic simulation and macroscopic properties,a generalized formula is derived from the simulation data to calculate the diffusion coefficient.This work helps to advise the diffusion modulation of gas molecules via structural design of catalysts and regulation of reaction conditions.
基金jointly supported by the National Natural Science Foundation of China(Nos.21903026,21975081,21975079,21676106)Science and Technology Program of Guangdong Province(2017A050506015)+2 种基金Science and Technology Program of Guangzhou(201704030065)China Postdoctoral Science Foundation(2019M652877)the Fundamental Research Funds for the Central Universities。
文摘Nanocollision electrochemistry is employed to evaluate the ORR’s activity of one single Pt nanoparticle,the effect of the size and ligand is investigated.The size-normalized activity of the Pt nanoparticle of 4 nm is two times higher than that of 25 nm,confirming that the intrinsic activity does depend on the size of the nanoparticles.It is further found that the adsorbed ligand does yield effect on electrocatalysis,and the adsorption strength follows the order of PVP>CTAB>citrate.This work is of significance to understand the nature of the ORR’s electrocatalysis at the level of an individual entity,which makes the structure-activity correlation in a more reliable way.
基金financially supported by the National Natural Science Foundation of China(22078148 and 21727818)the Innovative Research Team Program by the Ministry of Education of China(IRT_17R54)+3 种基金the Top-notch Academic Programs Project of Jiangsu Higher Education Institutions(TAPP)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the Key Project by Medical Science and Technology Development Foundation of Nanjing Department of Health(ZKX17014)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX20_1021)。
文摘Nowadays,water pollution has become more serious,greatly affecting human life and healthy.Electrochemical biosensor,a novel and rapid detection technique,plays an important role in the realtime and trace detection of water pollutants.However,the stability and sensitivity of electrochemical biosensors remain a great challenge for practical detections in real samples to the strong interferences derived from complex components and coagulation effects.In this work,we reported a novel threedimensional architecture of Prussian blue nanoparticles(PBNPs)/Pt nanoparticles(PtNPs)composite film,using 3 D interweaved carbon nanofibers as a supporting matrix,for the construction of screenprinted microchips-based biosensor.PtNPs with diameters of-2.5 nm was highly dispersed on the carbon nanofibers(CNFs)to build a 3 D skeleton nanostructure through a solvothermal reduction.Subsequently,uniform PBNPs were in-situ self-assembled on this skeleton to construct a 3 D architecture of PB/Pt-CNF composite film.Due to the synergistic effects derived from this special feature,the as-prepared hydroquinone(HQ)biosensor chips can synchronously promote both surface area and conductivity to greatly enhance the electrocatalysis from enzymatic reaction.This biosensor has exhibited a high sensitivity of 220.28μA·L·mmol^(-1)·cm^(-2) with an ultrawide linear range from 2.5μmol·L^(-1) to 1.45 mmol·L^(-1) at a low potential of 0.15 V,as well as the satisfactory reproducibility and usage stability.Besides,its accuracy was also verified in the assays of real water samples.It is highly expected that the 3 D PB/Pt-CNF based screen-printed microchips will have wide applications in dynamic monitoring and early warning of analytes in the various practical fields.
基金supported by the National Natural Science Foundation of China(21872032)。
文摘Photocatalytic upgrading of renewable biomass is a promising way to relieve energy crisis and environmental pollution.However,low photocatalytic efficiency and uncontrollable selectivity still limit its development.Herein,ultrathin SnNb_(2)O_(6)nanosheets with high dispersed Pt nanoparticles(Pt/SN)were successfully developed as an efficient photocatalyst for the precise hydrogenation of furfural(FUR)to furfuryl alcohol(FOL)under visible light irradiation and exhibited the high conversion of FUR(99.9%)with the high selectivity for FOL(99.9%).It was revealed that SN with only 4.1 nm thickness possess good separation ability of photo-generated carriers and abundant surface Lewis acid sites(Nb^(5+))which would selectively chemisorb and activate FUR molecules via the Nb···O=C coordination.Meanwhile,Pt nanoparticles would gather photo-generated electrons for greatly promoting the generation of active H species to support the hydrogenation of FUR to FOL.The synergistic effects between SnNb_(2)O_(6)nanosheets and Pt nanoparticles remarkably facilitate the photocatalytic performance for hydrogenation.This work not only confirms the great potential of ultrathin nanosheet photocatalyst with functional metal sites for precise upgrading of biomass but also provides an in-depth view to understand the surface/interface interaction between reactant molecules and surface sites of a photocatalyst.
基金supported by the Natural Science Foundation of the Shanxi Province of China(No.201801D121069)Graduate Education Innovation Foundation of Province Shanxi of China(No.2020SY359)。
文摘The loading strategy of cocatalysts affects its activity exerting and atom utilization.Here,a novel strategy for loading precious metal(Pt)cocatalysts by means of ultrathin N-doped carbon layer is reported.The strategy is based on a pyrolysis process of predesigned N-containing polymers and Pt complexes on hard-template surface,during which Pt can be reduced by carbon from pyrolysis at high temperatures.Finally,the hollow TiO_(2)composite with stable and dispersed Pt on its inner surface was prepared.It shows an ultrahigh photocatalytic H_(2)production activity as high as 25.7 mmol h^(-1)g^(-1)with methanol as sacrificial regent,and displays an apparent quantum yield as 13.2%.The improved photocatalytic activity and stability can be attributed to the highly dispersed and ultrafine Pt nanoparticles,enhanced interaction between Pt-species and carbon support,fast photo-excited electron transport from the high graphitization degree of NC layers,ample oxygen vacancies/defects,as well as the manipulated local charge distribution of Pt/NC-layer configuration.Additionally,the universality of the proposed strategy was demonstrated by replacing metal sources(such as,Ru and Pd).This work presented a promising strategy for the design and development of novel photocatalysts,which shows a broad application prospect.
基金financially supported by Research Equipment Development Project of Chinese Academy of Sciences(No.YJKYYQ20210014).
文摘Photo-catalytic oxidation of intracellular nicotinamide adenine dinucleotide(2'-phosphate)(NAD(P)H)has attracted much attention for cancer therapy.However,the general oxygen-dependent mechanism heavily depresses the efficacy in hypoxic tumors.To solve this problem,herein platinum nanoparticles(Pt NPs)with catalase-like(CAT-like)and catalytic H_(2)evolution activities were introduced as a powerful assistant to enhance the photo-catalytic NAD(P)H oxidation of Ru1([Ru(phen)2(PIP-OCH_(3))]^(2+),phen=1,10-phenanthroline,PIP-OCH_(3)=2-(4-methoxy phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline)under hypoxic and even oxygen-free conditions.Firstly,Pt NPs can transform the original and in situ formed H_(2)O_(2)once again into O_(2)by the CAT-like activity,thus relieving tumor hypoxia and realizing cyclic utilization(at least in part)of the precious oxygen in hypoxia.Secondly,Pt NPs can also be served as H_(2)evolution catalysts while using Ru1 as the photosensitizer and NAD(P)H as the electron and proton donor.In this process,NAD(P)H is oxidized without the participation of oxygen,which can provide an effective way even under oxygen-free conditions.Via co-encapsulation of Rul and Pt NPs in bovine serum albumin(BSA)with tumor targeting ability,the resultant Ru/Pt@BSA could photo-catalyze intracellular NAD(P)H oxidation under hypoxic conditions(3%O_(2)),and exhibited an efficient and selective anticancer activity both in vitro and in vivo.Our results may provide new sights for efficient and targeted cancer treatment underhypoxic conditions.
基金the financial support of the Australian Research Council (ARC) projectsUSyd Early Career Researcher Scheme+2 种基金Major Equipment Schemethe scholarships provided by China Scholarship Council (CSC)the Commonwealth Scientific and Industrial Research Organization (CSIRO) OCE Top-up Scholarship
文摘This work reports a facile and efficient seed-mediated method for the synthesis of dendritic platinum (Pt) nanoparticles (NPs) at low temperatures of 55-60 ℃ in water, using L-ascorbic acid as a reducing agent and sodium citrate as a capping agent. It is found that the dendritic Pt NPs (10-150 nm) are composed of tiny Pt nanocrystals, which nucleate and grow through the introduced smaller Pt seeds with diameters of 3-5 nm. Further investigation shows that the dendritic Pt nanostructures display excellent catalytic performance in an aqueous-phase aromatic ketone hydrogenation reaction, including: (i) acetophenone conversion rate of 〉 90%, with smaller dendritic Pt NPs (10-46 nm) offering a higher conversion efficiency; (ii) high chemoselectivity toward carbonyl group (90.6%-91.5%), e.g., the selectivity to l-phenylethanol is -90.1% with nearly 100% acetophenone conversion for 10 nm dendritic Pt NPs within 60 rain, under mild reaction conditions (20 ℃, 1.5 bar H2 pressure, and 1.5 tool% catalyst). The high catalytic activity, selectivity and stability of the dendritic Pt nanostructures under the organic solvent-free conditions make them promising for many potential applications in green catalytic conversion of hydrophilic biomass derived compounds.
基金supported by the Six Talent Peaks Project in Jiangsu Province(No.JNHB-043)the Research Fund of State Key Laboratory of Materials-Oriented Chemical Engineering(No.ZK201713).
文摘Localized surface plasmon resonance(LSPR)effects of nanoscale plasmonic metals/semiconductor composites have been extensively applied into visible light photocatalysis.However,Pt nanoparticles(NPs)with the visible LSPR absorption maxima have rarely been used as a photosensitizer to facilitate photocatalytic reactions,especially the photocatalytic overall water splitting(POWS)reaction,presumably because they feature weak light absorption.Herein,we present that the increased plasmonic absorption and local field enhancement can be achieved in the wide visible range by exploiting the simulated and experimental expressions of Pt nanocuboctahedra and Pt cuboctahedra-WO_(3)nanohybrids(Pt-WO3).First,monodisperse Pt cuboctahedra with different sizes,a hierarchical WO_(3)nanoarchitecture composed of radially patterned WO_(3)nanopillars,and Pt-WO_(3)were systematically synthesized.Subsequently,visible plasmonic Pt-WO_(3)photocatalysts were employed in the POWS tests and exhibited the significant activity enhancement in the visible light region.The apparent quantum efficiency(AQE)of greater than 7%within the range of visible light has been achieved for the optimal Pt-WO3.
基金supported by the National Key Research and Development Program of China(grant No.2022YFB3807500)the National Natural Science Foundation of China(grant No.21922802,22220102003)+1 种基金the Beijing Natural Science Foundation(grant No.JQ19007)“Double-First-Class”construction projects(grant No.XK180301,XK1804-02).
文摘Based on the volcanic relationship between catalytic activity and key adsorption energies,Pt-Co alloy materials have been widely studied as cathode oxygen reduction reaction(ORR)catalysts in proton exchange membrane fuel cells(PEMFCs)due to their higher active surface area and adjustable D-band energy levels compared to Pt/C.However,how to balance the alloying degree and ORR performance of Pt-Co catalyst remains a great challenge.Herein,we first synthesized a well-dispersed Pt/Co/C precursor by using a mild dimethylamine borane(DMAB)as the reducing agent.The precursor was calcined at high temperature under H_(2)/Ar mixed gas by a secondary reduction strategy to obtain an ordered Pt_(3)Co intermetallic compound nanoparticle catalyst with a high degree of alloying.The optimization of elec-tronic structure due to Pt-Co alloying and the strong metal-carrier interaction ensure the high kinetic activity of the cell membrane electrode.Additionally,the high degree of graphitization increases the electrical conductivity during the reaction.As a result,the activity and stability of the catalyst were significantly improved,with a half-wave potential as high as 0.87 V,which decreased by only 20 mV after 10000 potential cycles.Single-cell tests further validate the high intrinsic activity of the ordered Pt_(3)Co catalyst with mass activity up to 0.67 A mg_(pt)^(-1),exceeding the United States Department of Energy(US DOE)standard(0.44 A mg_(pt)^(-1)),and a rated power of 5.93 W mg_(pt)^(-1).
基金supported by the National Natural Science Foundation of China(Nos.21577046 and 21871111)Wuhan Morning Light plan of Youth Science and Technology(No.2017050304010327)
文摘Efficient removal of formaldehyde from indoor environments is of significance for human health.In this work,a typical binary transition metal oxide that could provide various oxidation states,β-NiMoO4,was employed as a support to immobilize the active Pt component(Pt/NiMoO4)for catalytic formaldehyde elimination at low ambient temperature(15℃).The results showed that the hydrothermal preparation temperature and time had a noticeable impact on the morphology and catalytic activity of the samples.The catalyst prepared with hydrothermal temperature of 150℃for 4 hr(Pt-150-4)exhibited superior catalytic activity and stability mainly due to its distinctly porous structure,relative abundance of adsorbed surface hydroxyls/water,and high oxidation ability,which resulted from the interaction of Pt with Ni and Mo of the bimetallic NiMoO4 support.Our results might shed light on the rational design of multifunctional catalysts for removal of indoor air pollutants at low ambient temperature.
基金Project supported by the Joint Funds of the National Natural Science Foundation of China(U20A20132)。
文摘The LaCo_(0.94)Pt_(0.06)O_(3) catalyst is reduced under 5% H_(2)/Ar at different temperatures to get Pt/LaCoO_(3) with high catalytic activity for soot oxidation.Transmission electron microscopy(TEM),scanning electron microscopy(SEM),X-ray diffraction(XRD),Brunauer-Emmett-Teller method(BET),X-ray photoelectron spectroscopy(XPS),H_(2)-temperature programmed reduction(H_(2)-TPR),O_(2)-temperature programmed desorption(O_(2)-TPD) and thermogravimetric analysis(TGA) were used to study the physicochemical properties of the catalyst.SEM and TEM results indicate that Pt nanoparticles(<10 nm) are grown homogeneously on the surface of the LaCoO_(3) matrix after in-situ reduction.XRD shows that the reduced catalyst has a high symmetrical structure.TGA results indicate that all reduced catalysts exhibit an excellent activity,especially the catalyst reduced at 350℃(T_(10)=338℃,T_(50)=393℃,T_(90)=427℃).And perovskite is the primary active component.According to XPS study,the high symmetrical structure benefits the mobility of oxygen vacancy,and Pt nanoparticles induce the oxygen vacancy to move to its adjacent situation,resulting in more adsorbed oxygen on the surface of the reduced catalyst and increasing the activity.The possible reaction principle is also proposed.