Pt nanoparticles entrapped in ordered mesoporous CMK-3 carbons with p6mm symmetry were prepared using a facile impregnation method, and the resulting materials were characterized using X-ray diffraction spectroscopy, ...Pt nanoparticles entrapped in ordered mesoporous CMK-3 carbons with p6mm symmetry were prepared using a facile impregnation method, and the resulting materials were characterized using X-ray diffraction spectroscopy, N2 adsorption-desorption, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The Pt nanoparticles were highly dispersed in the CMK-3 with 43.7% dispersion. The Pt/CMK-3 catalyst was an effective catalyst for the liquid-phase hydrogenation of nitrobenzene and its derivatives under the experimental conditions studied here. The Pt/CMK-3 catalyst was more active than commercial Pt/C catalyst in most cases. A highest turnover frequency of 43.8 s-1 was measured when the Pt/CMK-3 catalyst was applied for the hydrogenation of 2-methyl-nitrobenzene in ethanol under optimal conditions. It is worthy of note that the Pt/CMK-3 catalyst could be recycled easily, and could be reused at least fourteen times without any loss in activity or selectivity for the hydrogenation of nitrobenzene in ethanol.展开更多
Platinum group metals(PGMs)usually exhibit promising aerobic catalytic abilities,providing a green and feasible oxidative desulfurization method.However,often,the PGM nanoparticles(NPs)get leached,and the catalysts ar...Platinum group metals(PGMs)usually exhibit promising aerobic catalytic abilities,providing a green and feasible oxidative desulfurization method.However,often,the PGM nanoparticles(NPs)get leached,and the catalysts are deactivated.In this work,Pt NPs with particle sizes of approximately 4–5 nm were encapsulated effectively and uniformly on the surface of vanadium pentoxide(V2O5)nanosheets(with thicknesses of approximately six atomic layers)through strong metal-support interactions.The synthesized catalysts promote catalytic aerobic oxidation reactions,realizing deep desulfurization(99.1%,<5μg g^(–1))under atmospheric pressure and 110℃reaction temperature.Remarkable degrees of sulfur removal could be achieved for oils with different initial S-concentrations and substrates.Additionally,the as-prepared catalysts could be recycled for reuse at least seven times.展开更多
To accelerate the kinetics of the oxygen reduction reaction(ORR)in proton exchange membrane fuel cells,ultrafine Pt nanoparticles modified with trace amounts of cobalt were fabricated and decorated on carbon black thr...To accelerate the kinetics of the oxygen reduction reaction(ORR)in proton exchange membrane fuel cells,ultrafine Pt nanoparticles modified with trace amounts of cobalt were fabricated and decorated on carbon black through a strategy involving modified glycol reduction and chemical etching.The obtained Pt36Co/C catalyst exhibits a much larger electrochemical surface area(ECSA)and an improved ORR electrocatalytic activity compared to commercial Pt/C.Moreover,an electrode prepared with Pt36Co/C was further evaluated under H2-air single cell test conditions,and exhibited a maximum specific power density of 10.27 W mgPt^-1,which is 1.61 times higher than that of a conventional Pt/C electrode and also competitive with most state-of-the-art Pt-based architectures.In addition,the changes in ECSA,power density,and reacting resistance during the accelerated degradation process further demonstrate the enhanced durability of the Pt36Co/C electrode.The superior performance observed in this work can be attributed to the synergy between the ultrasmall size and homogeneous distribution of catalyst nanoparticles,bimetallic ligand and electronic effects,and the dissolution of unstable Co with the rearrangement of surface structure brought about by acid etching.Furthermore,the accessible raw materials and simplified operating procedures involved in the fabrication process would result in great cost-effectiveness for practical applications of PEMFCs.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
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
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
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
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
Ordered mesoporous Mn2O3 (meso‐Mn2O3) and meso‐Mn2O3‐supported Pd, Pt, and Pd‐Pt alloy x(PdyPt)/meso‐Mn2O3; x = (0.10?1.50) wt%; Pd/Pt molar ratio (y) = 4.9?5.1 nanocatalysts were prepared using KIT‐6‐templated...Ordered mesoporous Mn2O3 (meso‐Mn2O3) and meso‐Mn2O3‐supported Pd, Pt, and Pd‐Pt alloy x(PdyPt)/meso‐Mn2O3; x = (0.10?1.50) wt%; Pd/Pt molar ratio (y) = 4.9?5.1 nanocatalysts were prepared using KIT‐6‐templated and poly(vinyl alcohol)‐protected reduction methods, respectively.The meso‐Mn2O3 had a high surface area, i.e., 106 m2/g, and a cubic crystal structure. Noble‐metalnanoparticles (NPs) of size 2.1?2.8 nm were uniformly dispersed on the meso‐Mn2O3 surfaces. AlloyingPd with Pt enhanced the catalytic activity in methane combustion; 1.41(Pd5.1Pt)/meso‐Mn2O3gave the best performance; T10%, T50%, and T90% (the temperatures required for achieving methaneconversions of 10%, 50%, and 90%) were 265, 345, and 425 °C, respectively, at a space velocity of20000 mL/(g?h). The effects of SO2, CO2, H2O, and NO on methane combustion over1.41(Pd5.1Pt)/meso‐Mn2O3 were also examined. We conclude that the good catalytic performance of1.41(Pd5.1Pt)/meso‐Mn2O3 is associated with its high‐quality porous structure, high adsorbed oxygen species concentration, good low‐temperature reducibility, and strong interactions between Pd‐Pt alloy NPs and the meso‐Mn2O3 support.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
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
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
Efficacious regulation of the geometric and electronic structures of carbon nanomaterials via the introduction of defects and their synergy is essential to achieving good electrochemical performance.However,the guidel...Efficacious regulation of the geometric and electronic structures of carbon nanomaterials via the introduction of defects and their synergy is essential to achieving good electrochemical performance.However,the guidelines for designing hybrid materials with advantageous structures and the fundamental understanding of their electrocatalytic mechanisms remain unclear.Herein,superfine Pt and PtCu nanoparticles supported by novel S,N‐co‐doped multi‐walled CNT(MWCNTs)were prepared through the innovative pyrolysis of a poly(3,4‐ethylenedioxythiophene)/polyaniline copolymer as a source of S and N.The uniform wrapping of the copolymer around the MWCNTs provides a high density of evenly distributed defects on the surface after the pyrolysis treatment,facilitating the uniform distribution of ultrafine Pt and PtCu nanoparticles.Remarkably,the Pt_(1)Cu_(2)/SN‐MWCNTs show an obviously larger electroactive surface area and higher mass activity,stability,and CO poisoning resistance in methanol oxidation compared to Pt/SN‐MWCNTs,Pt/S‐MWCNTs,Pt/N‐MWCNTs,and commercial Pt/C.Density functional theory studies confirm that the co‐doping of S and N considerably deforms the CNTs and polarizes the adjacent C atoms.Consequently,both the adsorption of Pt1Cu2 onto the SN‐MWCNTs and the subsequent adsorption of methanol are enhanced;in addition,the catalytic activity of Pt_(1)Cu_(2)/SN‐MWCNTs for methanol oxidation is thermodynamically and kinetically more favorable than that of its CNT and N‐CNT counterparts.This work provides a novel method to fabricate high‐performance fuel cell electrocatalysts with highly dispersed and stable Pt‐based nanoparticles on a carbon substrate.展开更多
The heterostructured NiWO_(4)/WO_(3) nanotubes(Ni/W NTs)were synthesized by using a facile self-assembly method on the sacrificial polystyrene(PS)nanofibers templates.Then,the Pt-decorated NiWO_(4)/WO_(3)(Pt@Ni/W)comp...The heterostructured NiWO_(4)/WO_(3) nanotubes(Ni/W NTs)were synthesized by using a facile self-assembly method on the sacrificial polystyrene(PS)nanofibers templates.Then,the Pt-decorated NiWO_(4)/WO_(3)(Pt@Ni/W)composite NTs were obtained through using an ultrasonic mixing method.The experimental results display that the order of gas-sensing performance is Pt@Ni/W>Ni/W>WO_(3).The 2wt.%Pt@Ni/W-5 NTs indicate the supreme acetone-sensing response(R_(air)/R_(gas)=58.4 at 100×10^(−6))at 375℃,which is 10.6 and 1.53 times that of the WO_(3) and NiWO_(4)/WO_(3) NTs,respectively.Additionally,the 2wt.%Pt@Ni/W-5 NTs also exhibit the dramatically high selectivity toward acetone against ethanol,methanal,methanol,NH_(3) and toluene.The Pt-decorated Ni/W NTs show the excellent responsivity and stability toward acetone,which is ascribed to the construction of heterostructured NiWO_(4)/WO_(3) and the spill-over effect of Pt nanoparticles.展开更多
A facile impregnation method under mild condition is designed for synthesis of highly dispersed Pt nanoparticles with a narrow size of 4-7 nm on nitrogen-doped carbon nanotubes (CNx). CNx do not need any pre-surface...A facile impregnation method under mild condition is designed for synthesis of highly dispersed Pt nanoparticles with a narrow size of 4-7 nm on nitrogen-doped carbon nanotubes (CNx). CNx do not need any pre-surface modification due to the inherent chemical activity. The structure and nature of Pt/CNx were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and energy dispersive spectroscopy spectrum. All the experimental results revealed that the large amount of doped nitrogen atoms in CNx was virtually effective for capturing the Pt(IV) ions. The improved surface nitrogen functionalities and hydrophilicity contributed to the good dispersion and immobi- lization of Pt nanoparticles on the CNx surface. The Pt/CNx served as active and reusable catalysts in the hydrogenation of allyl alcohol. This could be attributed to high dispersion of Pt nanoparticles and stronger interaction between Pt and the supports, which prevented the Pt nanoparticles from aggregating into less active Pt black and from leaching as well.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
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
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
基金supported by the National Natural Science Foundation of China(21273076 and 21373089)the Open Research Fund of Top Key Discipline of Chemistry in Zhejiang Provincial Colleges and Key Laboratory of the Ministry of Education for Catalysis Materials(Zhejiang Normal University,ZJHX2013)Shanghai Leading Academic Discipline Project (B409)~~
文摘Pt nanoparticles entrapped in ordered mesoporous CMK-3 carbons with p6mm symmetry were prepared using a facile impregnation method, and the resulting materials were characterized using X-ray diffraction spectroscopy, N2 adsorption-desorption, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The Pt nanoparticles were highly dispersed in the CMK-3 with 43.7% dispersion. The Pt/CMK-3 catalyst was an effective catalyst for the liquid-phase hydrogenation of nitrobenzene and its derivatives under the experimental conditions studied here. The Pt/CMK-3 catalyst was more active than commercial Pt/C catalyst in most cases. A highest turnover frequency of 43.8 s-1 was measured when the Pt/CMK-3 catalyst was applied for the hydrogenation of 2-methyl-nitrobenzene in ethanol under optimal conditions. It is worthy of note that the Pt/CMK-3 catalyst could be recycled easily, and could be reused at least fourteen times without any loss in activity or selectivity for the hydrogenation of nitrobenzene in ethanol.
文摘Platinum group metals(PGMs)usually exhibit promising aerobic catalytic abilities,providing a green and feasible oxidative desulfurization method.However,often,the PGM nanoparticles(NPs)get leached,and the catalysts are deactivated.In this work,Pt NPs with particle sizes of approximately 4–5 nm were encapsulated effectively and uniformly on the surface of vanadium pentoxide(V2O5)nanosheets(with thicknesses of approximately six atomic layers)through strong metal-support interactions.The synthesized catalysts promote catalytic aerobic oxidation reactions,realizing deep desulfurization(99.1%,<5μg g^(–1))under atmospheric pressure and 110℃reaction temperature.Remarkable degrees of sulfur removal could be achieved for oils with different initial S-concentrations and substrates.Additionally,the as-prepared catalysts could be recycled for reuse at least seven times.
基金supported by the National Major Research Project(2016YFB0101208)the National Natural Science Foundation of China(21576257)+1 种基金the Natural Science Foundation-Liaoning United Fund(U1508202)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB06050303)~~
文摘To accelerate the kinetics of the oxygen reduction reaction(ORR)in proton exchange membrane fuel cells,ultrafine Pt nanoparticles modified with trace amounts of cobalt were fabricated and decorated on carbon black through a strategy involving modified glycol reduction and chemical etching.The obtained Pt36Co/C catalyst exhibits a much larger electrochemical surface area(ECSA)and an improved ORR electrocatalytic activity compared to commercial Pt/C.Moreover,an electrode prepared with Pt36Co/C was further evaluated under H2-air single cell test conditions,and exhibited a maximum specific power density of 10.27 W mgPt^-1,which is 1.61 times higher than that of a conventional Pt/C electrode and also competitive with most state-of-the-art Pt-based architectures.In addition,the changes in ECSA,power density,and reacting resistance during the accelerated degradation process further demonstrate the enhanced durability of the Pt36Co/C electrode.The superior performance observed in this work can be attributed to the synergy between the ultrasmall size and homogeneous distribution of catalyst nanoparticles,bimetallic ligand and electronic effects,and the dissolution of unstable Co with the rearrangement of surface structure brought about by acid etching.Furthermore,the accessible raw materials and simplified operating procedures involved in the fabrication process would result in great cost-effectiveness for practical applications of PEMFCs.
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supported by the Ph.D.Program Foundation of Ministry of Education of China(20131103110002)the NNSF of China(21377008)+2 种基金National High Technology Research and Development Program(863 Program,2015AA034603)Foundation on the Creative Research Team Con-struction Promotion Project of Beijing Municipal InstitutionsScientific Research Base Construction-Science and Technology Creation Plat-form-National Materials Research Base Construction~~
文摘Ordered mesoporous Mn2O3 (meso‐Mn2O3) and meso‐Mn2O3‐supported Pd, Pt, and Pd‐Pt alloy x(PdyPt)/meso‐Mn2O3; x = (0.10?1.50) wt%; Pd/Pt molar ratio (y) = 4.9?5.1 nanocatalysts were prepared using KIT‐6‐templated and poly(vinyl alcohol)‐protected reduction methods, respectively.The meso‐Mn2O3 had a high surface area, i.e., 106 m2/g, and a cubic crystal structure. Noble‐metalnanoparticles (NPs) of size 2.1?2.8 nm were uniformly dispersed on the meso‐Mn2O3 surfaces. AlloyingPd with Pt enhanced the catalytic activity in methane combustion; 1.41(Pd5.1Pt)/meso‐Mn2O3gave the best performance; T10%, T50%, and T90% (the temperatures required for achieving methaneconversions of 10%, 50%, and 90%) were 265, 345, and 425 °C, respectively, at a space velocity of20000 mL/(g?h). The effects of SO2, CO2, H2O, and NO on methane combustion over1.41(Pd5.1Pt)/meso‐Mn2O3 were also examined. We conclude that the good catalytic performance of1.41(Pd5.1Pt)/meso‐Mn2O3 is associated with its high‐quality porous structure, high adsorbed oxygen species concentration, good low‐temperature reducibility, and strong interactions between Pd‐Pt alloy NPs and the meso‐Mn2O3 support.
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.
文摘Efficacious regulation of the geometric and electronic structures of carbon nanomaterials via the introduction of defects and their synergy is essential to achieving good electrochemical performance.However,the guidelines for designing hybrid materials with advantageous structures and the fundamental understanding of their electrocatalytic mechanisms remain unclear.Herein,superfine Pt and PtCu nanoparticles supported by novel S,N‐co‐doped multi‐walled CNT(MWCNTs)were prepared through the innovative pyrolysis of a poly(3,4‐ethylenedioxythiophene)/polyaniline copolymer as a source of S and N.The uniform wrapping of the copolymer around the MWCNTs provides a high density of evenly distributed defects on the surface after the pyrolysis treatment,facilitating the uniform distribution of ultrafine Pt and PtCu nanoparticles.Remarkably,the Pt_(1)Cu_(2)/SN‐MWCNTs show an obviously larger electroactive surface area and higher mass activity,stability,and CO poisoning resistance in methanol oxidation compared to Pt/SN‐MWCNTs,Pt/S‐MWCNTs,Pt/N‐MWCNTs,and commercial Pt/C.Density functional theory studies confirm that the co‐doping of S and N considerably deforms the CNTs and polarizes the adjacent C atoms.Consequently,both the adsorption of Pt1Cu2 onto the SN‐MWCNTs and the subsequent adsorption of methanol are enhanced;in addition,the catalytic activity of Pt_(1)Cu_(2)/SN‐MWCNTs for methanol oxidation is thermodynamically and kinetically more favorable than that of its CNT and N‐CNT counterparts.This work provides a novel method to fabricate high‐performance fuel cell electrocatalysts with highly dispersed and stable Pt‐based nanoparticles on a carbon substrate.
基金supported by the National Natural Science Foundation of China (Nos. 51772130, 51972145)。
文摘The heterostructured NiWO_(4)/WO_(3) nanotubes(Ni/W NTs)were synthesized by using a facile self-assembly method on the sacrificial polystyrene(PS)nanofibers templates.Then,the Pt-decorated NiWO_(4)/WO_(3)(Pt@Ni/W)composite NTs were obtained through using an ultrasonic mixing method.The experimental results display that the order of gas-sensing performance is Pt@Ni/W>Ni/W>WO_(3).The 2wt.%Pt@Ni/W-5 NTs indicate the supreme acetone-sensing response(R_(air)/R_(gas)=58.4 at 100×10^(−6))at 375℃,which is 10.6 and 1.53 times that of the WO_(3) and NiWO_(4)/WO_(3) NTs,respectively.Additionally,the 2wt.%Pt@Ni/W-5 NTs also exhibit the dramatically high selectivity toward acetone against ethanol,methanal,methanol,NH_(3) and toluene.The Pt-decorated Ni/W NTs show the excellent responsivity and stability toward acetone,which is ascribed to the construction of heterostructured NiWO_(4)/WO_(3) and the spill-over effect of Pt nanoparticles.
基金ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China (No.21101105 and No.51174274), Innovation Program supported by Shanghai Municipal Education Commission (No.12ZZ195 and No.13YZ134), Shanghai Educational Development Foundation and the Shanghai Municipal Education Commission (No.12CG66), "Shu Guang" Project supported by Shanghai Municipal Education Commission (No.09SG54), and Shanghai Municipal Natural Science Foundation (No.13ZR1454800).
文摘A facile impregnation method under mild condition is designed for synthesis of highly dispersed Pt nanoparticles with a narrow size of 4-7 nm on nitrogen-doped carbon nanotubes (CNx). CNx do not need any pre-surface modification due to the inherent chemical activity. The structure and nature of Pt/CNx were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and energy dispersive spectroscopy spectrum. All the experimental results revealed that the large amount of doped nitrogen atoms in CNx was virtually effective for capturing the Pt(IV) ions. The improved surface nitrogen functionalities and hydrophilicity contributed to the good dispersion and immobi- lization of Pt nanoparticles on the CNx surface. The Pt/CNx served as active and reusable catalysts in the hydrogenation of allyl alcohol. This could be attributed to high dispersion of Pt nanoparticles and stronger interaction between Pt and the supports, which prevented the Pt nanoparticles from aggregating into less active Pt black and from leaching as well.
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.