The high-performance anodic electrocatalysts is pivotal for realizing the commercial application of the direct formic acid fuel cells.In this work,a simple polyethyleneimine-assisted galvanic replacement reaction is a...The high-performance anodic electrocatalysts is pivotal for realizing the commercial application of the direct formic acid fuel cells.In this work,a simple polyethyleneimine-assisted galvanic replacement reaction is applied to synthesize the high-quality PtTe alloy nanowires(PtTe NW)by using Te NW as an efficient sacrificial template.The existence of Te atoms separates the continuous Pt atoms,triggering a direct reaction pathway of formic acid electrooxidation reaction(FAEOR)at PtTe NW.The one-dimensional architecture and highly active sites have enabled PtTe NW to reveal outstanding electrocatalytic activity towards FAEOR with the mass/specific activities of 1091.25 mA mg^(-1)/45.34 A m^(-2)at 0.643 V potential,which are 44.72/23.16 and 20.26/11.75 times bigger than those of the commercial Pt and Pd nanoparticles,respectively.Density functional theory calculations reveal that Te atoms optimize the electronic structure of Pt atoms,which decreases the adsorption capacity of CO intermediate and simultaneously improves the durability of PtTe NW towards FAEOR.This work provides the valuable insights into the synthesis and design of efficient Pt-based alloy FAEOR electrocatalysts.展开更多
Direct methanol fuel cells (DMFCs) are very promising power source for stationary and portable miniatureelectric appliances due to its high efficiency and low emissions of pollutants. As the key material, cata-lysts...Direct methanol fuel cells (DMFCs) are very promising power source for stationary and portable miniatureelectric appliances due to its high efficiency and low emissions of pollutants. As the key material, cata-lysts for both cathode and anode face several problems which hinder the commercialization of DMFCs.In this review, we mainly focus on anode catalysts of DMFCs. The process and mechanism of methanolelectrooxidation on Pt and Pt-based catalysts in acidic medium have been introduced. The influences ofsize effect and morphology on electrocatalytic activity are discussed though whether there is a size effectin MOP, catalyst is under debate. Besides, the non Pt catalysts are also listed to emphasize though Pt isstill deemed as the indispensable element in anode catalyst of DMFCs in acidic medium. Different cata-lyst systems are compared to illustrate the level of research at present. ome debates need to be verifiedwith experimental evidences.展开更多
The factors affecting the electrooxidation of hydroxypivalaldehyde(HPAL) in an undivided cell were studied by using cyclic voltammetry(CV), linear scan voltammetry( LSV), and potentiostatic electrolysis. The ele...The factors affecting the electrooxidation of hydroxypivalaldehyde(HPAL) in an undivided cell were studied by using cyclic voltammetry(CV), linear scan voltammetry( LSV), and potentiostatic electrolysis. The electrocatalytic activity and stability of a PbO2 electrode in sulfuric acid, acetic acid, and phosphoric acid were studied. The selectivity and the current efficiency for producing hydroxypivalic acid were explored with different supporting electrolytes, concentrations of HPAL, and pH values. The results show that higher selectivity and current efficiency for producing hydroxypivalic acid can be achieved when sulfuric acid with a high concentration is used as the supporting electrolyte and the selectivity and the current efficiency can reach 80% and 60%. resvectively.展开更多
Carbon modified TiO_2 nanobelts(TiO_2-C) were synthesized using a hydrothermal growth method,as a support material for palladium(Pd) nanoparticles(Pd/TiO_2-C) to improve the electrocatalytic performance for methanol e...Carbon modified TiO_2 nanobelts(TiO_2-C) were synthesized using a hydrothermal growth method,as a support material for palladium(Pd) nanoparticles(Pd/TiO_2-C) to improve the electrocatalytic performance for methanol electrooxidation by comparison to Pd nanoparticles on bare TiO_2 nanobelts(Pd/TiO_2)and activated carbon(Pd/AC). Cyclic voltammetry characterization was conducted with respect to saturated calomel electrode(SCE) in an alkaline methanol solution, and the results indicate that the specific activity of Pd/TiO_2-C is 2.2 times that of Pd/AC and 1.5 times that of Pd/TiO_2. Chronoamperometry results revealed that the TiO_2-C support was comparable in stability to activated carbon, but possesses an enhanced current density for methanol oxidation at a potential of -0.2 V vs. SCE. The current study demonstrates the potential of Pd nanoparticle loaded on hierarchical TiO_2-C nanobelts for electrocatalytic applications such as fuel cells and batteries.展开更多
Electrocatalysts for ethanol oxidation reaction(EOR)are generally limited by their poor durability because of the catalyst poisoning induced by the reaction intermediate carbon monoxide(CO).Therefore,the rapid oxidati...Electrocatalysts for ethanol oxidation reaction(EOR)are generally limited by their poor durability because of the catalyst poisoning induced by the reaction intermediate carbon monoxide(CO).Therefore,the rapid oxidation removal of CO intermediates is crucial to the durability of EOR-based catalysts.Herein,in order to effectively avoiding the catalyst CO poisoning and improve the durability,the graphene-nickel nitride hybrids(AG-Ni_(3)N)were designed for supporting palladium nanoparticles(Pd/AG-Ni_(3)N)and then used for ethanol electrooxidation.The density functional theory(DFT)calculations demonstrated the introduction of AG-Ni_(3)N depresses the CO absorption and simultaneously promotes the adsorption of OH species for CO oxidation removal.The fabricated Pd/AG-Ni_(3)N catalyst distinctively exhibits excellent electroactivity with the mass catalytic activity of 3499.5 m A mg^(-1) on EOR in alkaline media,which is around 5.24 times higher than Pd/C(commercial catalyst).Notably,the Pd/AG-Ni_(3)N hybrids display excellent stability and durability after chronoamperometric measurements with a total operation time of 150,000 s.展开更多
The synthesis of ultrasmall metal nanoclusters(NCs) with high catalytic activities is of great importance for the development of clean and renewable energy technologies but remains a challenge. Here we report a facile...The synthesis of ultrasmall metal nanoclusters(NCs) with high catalytic activities is of great importance for the development of clean and renewable energy technologies but remains a challenge. Here we report a facile wet-chemical method to prepare ~1.0 nm Au Pd NCs supported on amine-functionalized carbon blacks. The Au Pd NCs exhibit a specific activity of 5.98 mA cm_(AuPd)^(-2)and mass activity of 5.25 A mg_(auPd)^(-1) for ethanol electrooxidation, which are far better than those of commercial Pd/C catalysts(1.74 mAcm_(AuPd)^(-2) and 0.54 A mg_(Pd)^(-1) ). For formic acid dehydrogenation, the Au Pd NCs have an initial turn over frequency of 49339 h^(-1) at 298 K without any additive, which is much higher than those obtained for most of reported Au Pd catalysts. The reported synthesis may represent a facile and low-cost approach to prepare other ultrasmall metal NCs with high catalytic activities for various applications.展开更多
A core shell structured C@MoxTi1-xO2-δnanocrystal with a functionalized interface(C@MTNC-FI)was fabricated via the hydrothermal method with subsequent annealing derived from tetrabutyl orthotitanate.The formation of ...A core shell structured C@MoxTi1-xO2-δnanocrystal with a functionalized interface(C@MTNC-FI)was fabricated via the hydrothermal method with subsequent annealing derived from tetrabutyl orthotitanate.The formation of anatase TiO2 was inhibited by the simultaneous presence of the hydrothermal etching/regrowth process,infiltration of Mo dopants and carbon coating,which endows the C@MTNC-FI with an ultrafine crystalline architecture that has a Mo-functionalized interface and carbon-coated shell.Pt Ru nanoparticles(NPs)were supported on C@MTNC-FI by employing a microwave-assisted polyol process(MAPP).The obtained Pt Ru/C@MTNC-FI catalyst has 2.68 times higher mass activity towards methanol electrooxidation than that of the un-functionalized catalyst(Pt Ru/C@TNC)and 1.65 times higher mass activity than that of Pt Ru/C catalyst with over 25%increase in durability.The improved catalytic performance is due to several aspects including ultrafine crystals of TiO2 with abundant grain boundaries,Mofunctionalized interface with enhanced electron interactions,and core shell architecture with excellent electrical transport properties.This work suggests the potential application of an interface-functionalized crystalline material as a sustainable and clean energy solution.展开更多
Carbon supported Pt(Pt/C) electrocatalysts were prepared with glucose as protection agent and NaBH 4 as reductant.The Pt nanoparticles deposited on carbon support presented reduced size and well dispersity attribute...Carbon supported Pt(Pt/C) electrocatalysts were prepared with glucose as protection agent and NaBH 4 as reductant.The Pt nanoparticles deposited on carbon support presented reduced size and well dispersity attributed to the protection effect of glucose.Glucose absorbed on the particle surface was readily removed by water washing without leading to agglomeration of the Pt nanoparticles.The as-prepared Pt/C electrocatalysts showed improved mass activity for methanol electrooxidation compared to the catalyst prepared without glucose protection.The improved performance is attributed to the larger electrochemical active surface area thus increased active sites on the Pt/C elctrocatalysts prepared under the protection of glucose.展开更多
Direct liquid fuel cells(DLFCs) have received increasing attention because of their high energy densities,instant recharging abilities, simple cell structure, and facile storage and transport. The main challenge for t...Direct liquid fuel cells(DLFCs) have received increasing attention because of their high energy densities,instant recharging abilities, simple cell structure, and facile storage and transport. The main challenge for the commercialization of DLFCs is the high loading requirement of platinum group metals(PGMs) as catalysts. Atomically dispersed catalysts(ADCs) have been brought into recent focus for DLFCs due to their well-defined active sites, high selectivity, maximal atom-utilization, and anti-poisoning property. In this review, we summarized the structure–property relationship for unveiling the underlying mechanisms of ADCs for DLFCs. More specifically, different types of fuels used in DLFCs such as methanol, formic acid,and ethanol were discussed. At last, we highlighted current challenges, research directions, and future outlooks towards the practical application of DLFCs.展开更多
In this work,three cytosine derived nitrogen doped carbonaceous materials(noble carbons,NCs)with different atomic C/N ratios and porous networks have been synthesized and used as supports for Pt Ru electrocatalysts in...In this work,three cytosine derived nitrogen doped carbonaceous materials(noble carbons,NCs)with different atomic C/N ratios and porous networks have been synthesized and used as supports for Pt Ru electrocatalysts in the ethanol oxidation reaction(EOR)for clean hydrogen production.Both,the metal phase and the carbon support play critical roles in the electrocatalysts final performance.Lower NPs size distribution was obtained over supports with low atomic C/N ratios(i.e.,4 and 6)and defined porosity(i.e.,1701 m^(2)g^(-1)for Pt Ru/CNZ and 1834 m^(2)g^(-1)for Pt Ru/CLZ,respectively).In contrast,a lower C/N ratio and poor porous network(i.e.,65 m^(2)g^(-1),Pt Ru/CLK)led to the largest particle size and fostered an increase of the alloying degree between Pt and Ru NPs(i.e.,3%for C/N~6 and 28%for C/N~3).Electrochemical active surface area was found to increase with decreasing NPs size and the alloy extent,due to a higher availability of Pt active sites.Accelerated degradation tests showed that Pt Ru/NCs outperform similar to Pt Ru NPs on commercial carbon pointing at the stabilizing effect of NCs.Pt Ru/CNZ exhibited the best electrochemical performance(i.e.,69.1 m A mgPt-1),outperforming Pt Ru/CLZ and Pt Ru/CLK by3-and 9-fold,respectively,due to a suitable compromise between particle sizes,degree of alloy,textural properties and elemental composition.Best anodes were scaled-up to a proton exchange membrane cell and Pt Ru/CNZ was proved to provide the best electrocatalytic activity(262 m A cm^(-2)and low energy requirements),matching the values obtained by the state of the art of EOR electrocatalysts.展开更多
The deactivation of nickel hydroxide to the electrooxidation of hypophosphite on anickel electrode was studied by means of in situ UV-Vis subtractive reflectance spectroscopy. Theexperimental results show that when th...The deactivation of nickel hydroxide to the electrooxidation of hypophosphite on anickel electrode was studied by means of in situ UV-Vis subtractive reflectance spectroscopy. Theexperimental results show that when the potential is lower than-1.0 V (SCE), the surfacc on nickelelectrode is free of nickel hydroxide, on which hypophosphite is active. When the potential movespositively to about-0.75V, two absorbency bands around 300 nm and 550 nm, which were ascribedto the formation of α-nickel hydroxide, were observed, nickel is oxidized to α-nickel hydroxide.Severe deactivation of the surface occurs when the nickel surface is covered with nickel hydroxide,which separates the hypophosphite ion from nickel substrate.展开更多
In an electrolytic cell with a proton exchange membrane, nicotinic acid was synthesized at the PbO2 anode. The relationship between the current density and the potential at different concentrations of 3-picoline and s...In an electrolytic cell with a proton exchange membrane, nicotinic acid was synthesized at the PbO2 anode. The relationship between the current density and the potential at different concentrations of 3-picoline and sulfuric acid as well as at different temperatures was studied with polarization curves. The effects of the concentrations of sulfuric acid and 3-picoline, the anode potential and the reaction temperature on the selectivity and the current efficiency were explored. The optimum conditions were determined by orthogonal experiments. Under optimum conditions the selectivity and the current efficiency for the synthesis of nicotinic acid might reach 89% and 65%, respectively. The, concentrations of 3-picoline and nicotinic acid were analyzed with high performance liquid chromatography and the product was characterized with elemental analysis, chromatography-mass spectrometry and IR spectrometry.展开更多
Four kinds of lanthanide ions(Sm^3+,Yb^3+,Eu^3+,La^3+)as an additive were added into the aqueous solution containing methanol,respectively,and their effects on methanol elecotrooxidation in aqueous solutions wer...Four kinds of lanthanide ions(Sm^3+,Yb^3+,Eu^3+,La^3+)as an additive were added into the aqueous solution containing methanol,respectively,and their effects on methanol elecotrooxidation in aqueous solutions were studied with cyclic voltammetry.The results show that the four kinds of ions have promotion action upon the electrooxidation of methanol to different degrees.The best additive,Sm^3+,can increase the anodic oxidation current of methanol by 80%and the peak potential shifted negatively about 50 mV.The promotion effects of the lanthanide ions were considered to be related to the extranuclear electron distribution of these ions and their adsorption on the Pt electrode surface.展开更多
In this paper In2O3nanoshells have been synthesized via a facile hydrothermal approach. The nanoshells can be completely cracked into pony-size nanocubes by annealing, which are then used as a support of Pt catalyst f...In this paper In2O3nanoshells have been synthesized via a facile hydrothermal approach. The nanoshells can be completely cracked into pony-size nanocubes by annealing, which are then used as a support of Pt catalyst for methanol and ethanol electrocatalytic oxidation. The prepared In2O3and supported Pt catalysts (Pt/In2O3) were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), field effect scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). Cyclic voltammetry (CV), linear sweep voltammetry (LSV), chronoamperometry and electrochemical impedance spectroscopy (EIS) were carried out, indicating the excellent catalytic performance for alcohol electrooxidation can be achieved on Pt/In2O3nanocatalysts due to the multiple active sites, high conductivity and a mass of microchannels and micropores for reactant diffusions arising from 3D frame structures compared with that on the Pt/C catalysts. ? 2016 Science Press展开更多
The electrooxidation of Mn(Ⅱ) on Pb Sb As alloy electrode in sulfuric acid has been investigated.In order to make the two steps of indirect electrosynthesis of benzaldehyde carried out in the same sulfuric acid conce...The electrooxidation of Mn(Ⅱ) on Pb Sb As alloy electrode in sulfuric acid has been investigated.In order to make the two steps of indirect electrosynthesis of benzaldehyde carried out in the same sulfuric acid concentration and also obtain high current efficiency of Mn(Ⅱ) to Mn(Ⅲ) and high yield of Mn(Ⅲ) oxidizing toluene to benzaldehyde in the mean time,the electrooxidation of Mn(Ⅱ) in 60% H 2SO 4 has been studied.Experimental results show that high current efficiency of Mn(Ⅲ) (about 75%) is obtained in 60%H 2SO 4 at 60℃.The reason affecting the current efficiency of Mn(Ⅲ) is discussed,and it is the coordination of sulfuric acid concentration and electrolytic temperature.The law is found that it is suitable for electrolysis at low temperature when sulfuric acid concentration is low and at high temperature when sulfuric acid concentration is high.展开更多
The electrooxidation of CO on Ru (0001) and RuO2 (100) electrode surfaces were characterized by cyclic voltammetry, AES and RHEED. The CO adlayer was first partially oxidized at 0.8 V, which is controlled by the atta...The electrooxidation of CO on Ru (0001) and RuO2 (100) electrode surfaces were characterized by cyclic voltammetry, AES and RHEED. The CO adlayer was first partially oxidized at 0.8 V, which is controlled by the attack of oxygen species toward the Ru(0001) surface. The remaining CO adlayer oxidation at 0.55 V is related to the combination of CO molecules with oxygen species already located on the surface. In contrast, successive peaks on RuO2(100) at 0.4 V and 0.72 V are observed, which shows that CO molecules can directly react with two different lattice-oxygen on the surface to carbon dioxide.展开更多
The electrooxidation of hydrogen on platinum and gold electrodes is comparatively described in this paper. The reaction is faster on platinum than on the gold surface, because the reactive diffuses inside of the gold ...The electrooxidation of hydrogen on platinum and gold electrodes is comparatively described in this paper. The reaction is faster on platinum than on the gold surface, because the reactive diffuses inside of the gold metal. This process is complicated with the lift of surface reconstruction of the (100) plane, which allows the fast penetration of the H atoms through the more open surface. The diffusion limiting current is then discontinued and the current falls. On platinum, the current fall occurs simultaneously with the metal oxide formation. It is assumed that the hydrogen helps the adsorbed OH group formation, which is the first step of metal oxidation, and it has been called “incipient hydrous oxide” (IHO). Current begins to fall slowly at the (IHO) potential. At higher potential the current falls abruptly.展开更多
Glucose fuel cells(GFCs)driven by abiotic catalysts are promising green power sources for portable or wearable devices.In this work,a CoO_(x)incorporated carbon nanofiber(CoO_(x)@CNF)catalyst with mixed valences cobal...Glucose fuel cells(GFCs)driven by abiotic catalysts are promising green power sources for portable or wearable devices.In this work,a CoO_(x)incorporated carbon nanofiber(CoO_(x)@CNF)catalyst with mixed valences cobalt oxides have been developed through partial oxidation of pyrolyzed electrospun Co^(2+)/poly acrylonitrile fibers.The cobalt valence modulating could be achieved via regulating the incorporation ratio of cobalt acetate in precursors or the oxidation temperature of the pyrolyzed fibers.Electrocatalytic analyses show that the presence of CoO in CoO_(x)@CNF will provide more active sites for glucose electrooxidation,and thus enhance the electrocatalytic performance significantly.As a result,the glucose fuel cell built with the CoO.@CNF anode containing both CoO and Co_(3)O_(4)delivered a maximum power density of 270μW cm^(-2),which is higher than that of other reported Co_(3)O_(4)based GFCs.This work provides a simple strategy to develop excellent transition metal catalysts for GFCs to expand their applications in portable and wearable energy devices.展开更多
Wormholelike mesoporous carbons (WMCs) with three different pore diameters (D-P), namely WMC-F7 (D-p = 8.5 nm), WMC-F30 (D-p =4.4 nm), and WMC-F0 (D-p =3.1 nm) are prepared via a modified sol-gel process. Then PtRu na...Wormholelike mesoporous carbons (WMCs) with three different pore diameters (D-P), namely WMC-F7 (D-p = 8.5 nm), WMC-F30 (D-p =4.4 nm), and WMC-F0 (D-p =3.1 nm) are prepared via a modified sol-gel process. Then PtRu nanoparticles with the particle size (40 of 3.2 nm supported on WMCs are synthesized with a modified pulse microwave-assisted polyol method. It is found that the pore diameter of WMCs plays an important role in the electrochemical activity of PtRu toward alcohol electrooxidation reaction. PtRu/WMC-F7 with D-p > 2d(pt) exhibits the largest electrochemical surface area (ESA) and the highest activity toward methanol electrooxidation. With the decrease in Dp, PtRu/WMC-F30 and PtRu/WMC-F0 have much lower ESA and electrochemical activity, especially for the isopropanol electrooxidation with a larger molecular size. When D-p is more than twice d(pt), the mass transfer of reactants and electrolyte are easier, and thus more PtRu nanoparticles can be utilized and the catalysts activity can be enhanced. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.展开更多
Single-atom catalysts(SACs)with high catalytic activity as well as great stability are demonstrating great promotion in electrocatalytic energy conversion,which is also a big challenge to achieve.Herein,we proposed a ...Single-atom catalysts(SACs)with high catalytic activity as well as great stability are demonstrating great promotion in electrocatalytic energy conversion,which is also a big challenge to achieve.Herein,we proposed a facile synthetic strategy to construct nickel-iron bimetallic hydroxide nanoribbon stabilized single-atom iridium catalysts(Ir-NiFe-OH),where the nickel-iron hydroxide nanoribbon not only can serve as good electronic conductor,but also can well stabilize and fully expose single-atom sites.Adopted as catalyst for urea oxidation reaction(UOR),it exhibited excellent UOR performance that it only needed a low operated potential of 1.38 V to achieve the current density of 100 mA·cm^(-2).In-situ Fourier transform infrared spectroscopy,X-ray absorption spectrum,and density functional theory calculations proved that Ir species are active centers and the existence of both Ni and Fe in the local structure of Ir atom can optimize the d-band center of Ir species,promoting the adsorption of intermediates and desorption of products for UOR.The hydrogen evolution reaction(HER)/UOR electrocatalytic cell demanded voltages of 1.46 and 1.50 V to achieve 50 and 100 mA·cm^(-2),respectively,which demonstrated a higher activity and better stability than those of conventional catalysts.This work opens a new avenue to develop catalysts for UORs with boosted activity and stability.展开更多
基金supported by the National Natural Science Foundation of China(22272103 and 52171145)the Science and Technology Innovation Team of Shaanxi Province(2023-CX-TD27)+1 种基金the Fundamental Research Funds for the Central Universities(GK202202001)the 111 Project(B14041 and D20015)。
文摘The high-performance anodic electrocatalysts is pivotal for realizing the commercial application of the direct formic acid fuel cells.In this work,a simple polyethyleneimine-assisted galvanic replacement reaction is applied to synthesize the high-quality PtTe alloy nanowires(PtTe NW)by using Te NW as an efficient sacrificial template.The existence of Te atoms separates the continuous Pt atoms,triggering a direct reaction pathway of formic acid electrooxidation reaction(FAEOR)at PtTe NW.The one-dimensional architecture and highly active sites have enabled PtTe NW to reveal outstanding electrocatalytic activity towards FAEOR with the mass/specific activities of 1091.25 mA mg^(-1)/45.34 A m^(-2)at 0.643 V potential,which are 44.72/23.16 and 20.26/11.75 times bigger than those of the commercial Pt and Pd nanoparticles,respectively.Density functional theory calculations reveal that Te atoms optimize the electronic structure of Pt atoms,which decreases the adsorption capacity of CO intermediate and simultaneously improves the durability of PtTe NW towards FAEOR.This work provides the valuable insights into the synthesis and design of efficient Pt-based alloy FAEOR electrocatalysts.
基金supported by the National Natural Science Foundation of China (21633008,21673221)the Jilin Province Science and Technology Development Program (20160622037JC,20170203003SF,and 20170520150JH)+1 种基金the Hundred Talents Program of the Chinese Academy of Sciencesthe Recruitment Program of Foreign Experts (WQ20122200077)
文摘Direct methanol fuel cells (DMFCs) are very promising power source for stationary and portable miniatureelectric appliances due to its high efficiency and low emissions of pollutants. As the key material, cata-lysts for both cathode and anode face several problems which hinder the commercialization of DMFCs.In this review, we mainly focus on anode catalysts of DMFCs. The process and mechanism of methanolelectrooxidation on Pt and Pt-based catalysts in acidic medium have been introduced. The influences ofsize effect and morphology on electrocatalytic activity are discussed though whether there is a size effectin MOP, catalyst is under debate. Besides, the non Pt catalysts are also listed to emphasize though Pt isstill deemed as the indispensable element in anode catalyst of DMFCs in acidic medium. Different cata-lyst systems are compared to illustrate the level of research at present. ome debates need to be verifiedwith experimental evidences.
基金Supported by the National Natural Science Foundation of China(No. 20373020).
文摘The factors affecting the electrooxidation of hydroxypivalaldehyde(HPAL) in an undivided cell were studied by using cyclic voltammetry(CV), linear scan voltammetry( LSV), and potentiostatic electrolysis. The electrocatalytic activity and stability of a PbO2 electrode in sulfuric acid, acetic acid, and phosphoric acid were studied. The selectivity and the current efficiency for producing hydroxypivalic acid were explored with different supporting electrolytes, concentrations of HPAL, and pH values. The results show that higher selectivity and current efficiency for producing hydroxypivalic acid can be achieved when sulfuric acid with a high concentration is used as the supporting electrolyte and the selectivity and the current efficiency can reach 80% and 60%. resvectively.
基金supported by FedDev Ontario through the Applied Research and Commercialization (ARC) Initiative and the Natural Sciences and Engineering Research Council of Canada (NSERC) programMicrobonds, Inc. for additional financial support
文摘Carbon modified TiO_2 nanobelts(TiO_2-C) were synthesized using a hydrothermal growth method,as a support material for palladium(Pd) nanoparticles(Pd/TiO_2-C) to improve the electrocatalytic performance for methanol electrooxidation by comparison to Pd nanoparticles on bare TiO_2 nanobelts(Pd/TiO_2)and activated carbon(Pd/AC). Cyclic voltammetry characterization was conducted with respect to saturated calomel electrode(SCE) in an alkaline methanol solution, and the results indicate that the specific activity of Pd/TiO_2-C is 2.2 times that of Pd/AC and 1.5 times that of Pd/TiO_2. Chronoamperometry results revealed that the TiO_2-C support was comparable in stability to activated carbon, but possesses an enhanced current density for methanol oxidation at a potential of -0.2 V vs. SCE. The current study demonstrates the potential of Pd nanoparticle loaded on hierarchical TiO_2-C nanobelts for electrocatalytic applications such as fuel cells and batteries.
基金funded by the National Natural Science Foundation of China(No.91745112)sponsored by Shanghai Rising-Star Program(No.19QA1404100)+1 种基金Financial support from the Science and Technology Commission of Shanghai Municipality(Nos.19DZ2271100 and 18020500800)the support from the Opening Project of PCOSS,Xiamen University,201910。
文摘Electrocatalysts for ethanol oxidation reaction(EOR)are generally limited by their poor durability because of the catalyst poisoning induced by the reaction intermediate carbon monoxide(CO).Therefore,the rapid oxidation removal of CO intermediates is crucial to the durability of EOR-based catalysts.Herein,in order to effectively avoiding the catalyst CO poisoning and improve the durability,the graphene-nickel nitride hybrids(AG-Ni_(3)N)were designed for supporting palladium nanoparticles(Pd/AG-Ni_(3)N)and then used for ethanol electrooxidation.The density functional theory(DFT)calculations demonstrated the introduction of AG-Ni_(3)N depresses the CO absorption and simultaneously promotes the adsorption of OH species for CO oxidation removal.The fabricated Pd/AG-Ni_(3)N catalyst distinctively exhibits excellent electroactivity with the mass catalytic activity of 3499.5 m A mg^(-1) on EOR in alkaline media,which is around 5.24 times higher than Pd/C(commercial catalyst).Notably,the Pd/AG-Ni_(3)N hybrids display excellent stability and durability after chronoamperometric measurements with a total operation time of 150,000 s.
基金supported by the National Natural Science Foundation of China (51901083)the Fundamental Research Funds for the Central Universities。
文摘The synthesis of ultrasmall metal nanoclusters(NCs) with high catalytic activities is of great importance for the development of clean and renewable energy technologies but remains a challenge. Here we report a facile wet-chemical method to prepare ~1.0 nm Au Pd NCs supported on amine-functionalized carbon blacks. The Au Pd NCs exhibit a specific activity of 5.98 mA cm_(AuPd)^(-2)and mass activity of 5.25 A mg_(auPd)^(-1) for ethanol electrooxidation, which are far better than those of commercial Pd/C catalysts(1.74 mAcm_(AuPd)^(-2) and 0.54 A mg_(Pd)^(-1) ). For formic acid dehydrogenation, the Au Pd NCs have an initial turn over frequency of 49339 h^(-1) at 298 K without any additive, which is much higher than those obtained for most of reported Au Pd catalysts. The reported synthesis may represent a facile and low-cost approach to prepare other ultrasmall metal NCs with high catalytic activities for various applications.
基金the National Natural Science Foundation of China (Grant Nos. 21273058, 21673064, 51802059 and 21503059)China Postdoctoral Science Foundation (Grant Nos. 2018M631938, 2018T110307 and 2017M621284)+1 种基金Heilongjiang Postdoctoral Fund (LBH-Z17074)Fundamental Research Funds for the Central Universities (Grant No. HIT. NSRIF. 2019040 and 2019041)
文摘A core shell structured C@MoxTi1-xO2-δnanocrystal with a functionalized interface(C@MTNC-FI)was fabricated via the hydrothermal method with subsequent annealing derived from tetrabutyl orthotitanate.The formation of anatase TiO2 was inhibited by the simultaneous presence of the hydrothermal etching/regrowth process,infiltration of Mo dopants and carbon coating,which endows the C@MTNC-FI with an ultrafine crystalline architecture that has a Mo-functionalized interface and carbon-coated shell.Pt Ru nanoparticles(NPs)were supported on C@MTNC-FI by employing a microwave-assisted polyol process(MAPP).The obtained Pt Ru/C@MTNC-FI catalyst has 2.68 times higher mass activity towards methanol electrooxidation than that of the un-functionalized catalyst(Pt Ru/C@TNC)and 1.65 times higher mass activity than that of Pt Ru/C catalyst with over 25%increase in durability.The improved catalytic performance is due to several aspects including ultrafine crystals of TiO2 with abundant grain boundaries,Mofunctionalized interface with enhanced electron interactions,and core shell architecture with excellent electrical transport properties.This work suggests the potential application of an interface-functionalized crystalline material as a sustainable and clean energy solution.
基金Supported by the National Innovative Research Program for Undergraduates,China(No.2010A33039)the Science and Technology Development Program of Jilin Province,China(No.20100420)
文摘Carbon supported Pt(Pt/C) electrocatalysts were prepared with glucose as protection agent and NaBH 4 as reductant.The Pt nanoparticles deposited on carbon support presented reduced size and well dispersity attributed to the protection effect of glucose.Glucose absorbed on the particle surface was readily removed by water washing without leading to agglomeration of the Pt nanoparticles.The as-prepared Pt/C electrocatalysts showed improved mass activity for methanol electrooxidation compared to the catalyst prepared without glucose protection.The improved performance is attributed to the larger electrochemical active surface area thus increased active sites on the Pt/C elctrocatalysts prepared under the protection of glucose.
基金financial supports from the National Science Foundation under Grant Nos. CBET-1949840 and CMMI-1851674financial support from the Preeminent Postdoctoral Program (P3) of the University of Central Florida。
文摘Direct liquid fuel cells(DLFCs) have received increasing attention because of their high energy densities,instant recharging abilities, simple cell structure, and facile storage and transport. The main challenge for the commercialization of DLFCs is the high loading requirement of platinum group metals(PGMs) as catalysts. Atomically dispersed catalysts(ADCs) have been brought into recent focus for DLFCs due to their well-defined active sites, high selectivity, maximal atom-utilization, and anti-poisoning property. In this review, we summarized the structure–property relationship for unveiling the underlying mechanisms of ADCs for DLFCs. More specifically, different types of fuels used in DLFCs such as methanol, formic acid,and ethanol were discussed. At last, we highlighted current challenges, research directions, and future outlooks towards the practical application of DLFCs.
基金the Spanish Ministry of Science and Innovation(State Research Agency.Project PID2019-107499RB100)for the financial supportThe Max Planck Society。
文摘In this work,three cytosine derived nitrogen doped carbonaceous materials(noble carbons,NCs)with different atomic C/N ratios and porous networks have been synthesized and used as supports for Pt Ru electrocatalysts in the ethanol oxidation reaction(EOR)for clean hydrogen production.Both,the metal phase and the carbon support play critical roles in the electrocatalysts final performance.Lower NPs size distribution was obtained over supports with low atomic C/N ratios(i.e.,4 and 6)and defined porosity(i.e.,1701 m^(2)g^(-1)for Pt Ru/CNZ and 1834 m^(2)g^(-1)for Pt Ru/CLZ,respectively).In contrast,a lower C/N ratio and poor porous network(i.e.,65 m^(2)g^(-1),Pt Ru/CLK)led to the largest particle size and fostered an increase of the alloying degree between Pt and Ru NPs(i.e.,3%for C/N~6 and 28%for C/N~3).Electrochemical active surface area was found to increase with decreasing NPs size and the alloy extent,due to a higher availability of Pt active sites.Accelerated degradation tests showed that Pt Ru/NCs outperform similar to Pt Ru NPs on commercial carbon pointing at the stabilizing effect of NCs.Pt Ru/CNZ exhibited the best electrochemical performance(i.e.,69.1 m A mgPt-1),outperforming Pt Ru/CLZ and Pt Ru/CLK by3-and 9-fold,respectively,due to a suitable compromise between particle sizes,degree of alloy,textural properties and elemental composition.Best anodes were scaled-up to a proton exchange membrane cell and Pt Ru/CNZ was proved to provide the best electrocatalytic activity(262 m A cm^(-2)and low energy requirements),matching the values obtained by the state of the art of EOR electrocatalysts.
文摘The deactivation of nickel hydroxide to the electrooxidation of hypophosphite on anickel electrode was studied by means of in situ UV-Vis subtractive reflectance spectroscopy. Theexperimental results show that when the potential is lower than-1.0 V (SCE), the surfacc on nickelelectrode is free of nickel hydroxide, on which hypophosphite is active. When the potential movespositively to about-0.75V, two absorbency bands around 300 nm and 550 nm, which were ascribedto the formation of α-nickel hydroxide, were observed, nickel is oxidized to α-nickel hydroxide.Severe deactivation of the surface occurs when the nickel surface is covered with nickel hydroxide,which separates the hypophosphite ion from nickel substrate.
文摘In an electrolytic cell with a proton exchange membrane, nicotinic acid was synthesized at the PbO2 anode. The relationship between the current density and the potential at different concentrations of 3-picoline and sulfuric acid as well as at different temperatures was studied with polarization curves. The effects of the concentrations of sulfuric acid and 3-picoline, the anode potential and the reaction temperature on the selectivity and the current efficiency were explored. The optimum conditions were determined by orthogonal experiments. Under optimum conditions the selectivity and the current efficiency for the synthesis of nicotinic acid might reach 89% and 65%, respectively. The, concentrations of 3-picoline and nicotinic acid were analyzed with high performance liquid chromatography and the product was characterized with elemental analysis, chromatography-mass spectrometry and IR spectrometry.
基金the National High-tech Research and Development Program of China(No.2002AA233051)the NationalNatural Science Foundation of China(No.20373019).
文摘Four kinds of lanthanide ions(Sm^3+,Yb^3+,Eu^3+,La^3+)as an additive were added into the aqueous solution containing methanol,respectively,and their effects on methanol elecotrooxidation in aqueous solutions were studied with cyclic voltammetry.The results show that the four kinds of ions have promotion action upon the electrooxidation of methanol to different degrees.The best additive,Sm^3+,can increase the anodic oxidation current of methanol by 80%and the peak potential shifted negatively about 50 mV.The promotion effects of the lanthanide ions were considered to be related to the extranuclear electron distribution of these ions and their adsorption on the Pt electrode surface.
基金sponsored by the National Basic Research Program of China(973 Program)under grant no.2015CB351905the National Natural Science Foundation of China(no.61504019)+3 种基金China Postdoctoral Science Foundation(no.2015M580783)Scientific Research Start-up Foundation of University of Electronic Science and Technology of China(Y02002010301082)the Technology Innovative Research Team of Sichuan Province of China(no.2015TD0005)the Fundamental Research Funds for the Central Universities of China(no.ZYGX2015J140)
文摘In this paper In2O3nanoshells have been synthesized via a facile hydrothermal approach. The nanoshells can be completely cracked into pony-size nanocubes by annealing, which are then used as a support of Pt catalyst for methanol and ethanol electrocatalytic oxidation. The prepared In2O3and supported Pt catalysts (Pt/In2O3) were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), field effect scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). Cyclic voltammetry (CV), linear sweep voltammetry (LSV), chronoamperometry and electrochemical impedance spectroscopy (EIS) were carried out, indicating the excellent catalytic performance for alcohol electrooxidation can be achieved on Pt/In2O3nanocatalysts due to the multiple active sites, high conductivity and a mass of microchannels and micropores for reactant diffusions arising from 3D frame structures compared with that on the Pt/C catalysts. ? 2016 Science Press
文摘The electrooxidation of Mn(Ⅱ) on Pb Sb As alloy electrode in sulfuric acid has been investigated.In order to make the two steps of indirect electrosynthesis of benzaldehyde carried out in the same sulfuric acid concentration and also obtain high current efficiency of Mn(Ⅱ) to Mn(Ⅲ) and high yield of Mn(Ⅲ) oxidizing toluene to benzaldehyde in the mean time,the electrooxidation of Mn(Ⅱ) in 60% H 2SO 4 has been studied.Experimental results show that high current efficiency of Mn(Ⅲ) (about 75%) is obtained in 60%H 2SO 4 at 60℃.The reason affecting the current efficiency of Mn(Ⅲ) is discussed,and it is the coordination of sulfuric acid concentration and electrolytic temperature.The law is found that it is suitable for electrolysis at low temperature when sulfuric acid concentration is low and at high temperature when sulfuric acid concentration is high.
文摘The electrooxidation of CO on Ru (0001) and RuO2 (100) electrode surfaces were characterized by cyclic voltammetry, AES and RHEED. The CO adlayer was first partially oxidized at 0.8 V, which is controlled by the attack of oxygen species toward the Ru(0001) surface. The remaining CO adlayer oxidation at 0.55 V is related to the combination of CO molecules with oxygen species already located on the surface. In contrast, successive peaks on RuO2(100) at 0.4 V and 0.72 V are observed, which shows that CO molecules can directly react with two different lattice-oxygen on the surface to carbon dioxide.
文摘The electrooxidation of hydrogen on platinum and gold electrodes is comparatively described in this paper. The reaction is faster on platinum than on the gold surface, because the reactive diffuses inside of the gold metal. This process is complicated with the lift of surface reconstruction of the (100) plane, which allows the fast penetration of the H atoms through the more open surface. The diffusion limiting current is then discontinued and the current falls. On platinum, the current fall occurs simultaneously with the metal oxide formation. It is assumed that the hydrogen helps the adsorbed OH group formation, which is the first step of metal oxidation, and it has been called “incipient hydrous oxide” (IHO). Current begins to fall slowly at the (IHO) potential. At higher potential the current falls abruptly.
基金We gratefully acknowledge to the financial support from the Chongqing Key Laboratory for Advanced MaterialsTechnologies of Clean Energies and Academician Station of Hainan Province(SQ2021PTZ0024).
文摘Glucose fuel cells(GFCs)driven by abiotic catalysts are promising green power sources for portable or wearable devices.In this work,a CoO_(x)incorporated carbon nanofiber(CoO_(x)@CNF)catalyst with mixed valences cobalt oxides have been developed through partial oxidation of pyrolyzed electrospun Co^(2+)/poly acrylonitrile fibers.The cobalt valence modulating could be achieved via regulating the incorporation ratio of cobalt acetate in precursors or the oxidation temperature of the pyrolyzed fibers.Electrocatalytic analyses show that the presence of CoO in CoO_(x)@CNF will provide more active sites for glucose electrooxidation,and thus enhance the electrocatalytic performance significantly.As a result,the glucose fuel cell built with the CoO.@CNF anode containing both CoO and Co_(3)O_(4)delivered a maximum power density of 270μW cm^(-2),which is higher than that of other reported Co_(3)O_(4)based GFCs.This work provides a simple strategy to develop excellent transition metal catalysts for GFCs to expand their applications in portable and wearable energy devices.
基金supported by the National Natural Science Foundation of China (no. 91434106)
文摘Wormholelike mesoporous carbons (WMCs) with three different pore diameters (D-P), namely WMC-F7 (D-p = 8.5 nm), WMC-F30 (D-p =4.4 nm), and WMC-F0 (D-p =3.1 nm) are prepared via a modified sol-gel process. Then PtRu nanoparticles with the particle size (40 of 3.2 nm supported on WMCs are synthesized with a modified pulse microwave-assisted polyol method. It is found that the pore diameter of WMCs plays an important role in the electrochemical activity of PtRu toward alcohol electrooxidation reaction. PtRu/WMC-F7 with D-p > 2d(pt) exhibits the largest electrochemical surface area (ESA) and the highest activity toward methanol electrooxidation. With the decrease in Dp, PtRu/WMC-F30 and PtRu/WMC-F0 have much lower ESA and electrochemical activity, especially for the isopropanol electrooxidation with a larger molecular size. When D-p is more than twice d(pt), the mass transfer of reactants and electrolyte are easier, and thus more PtRu nanoparticles can be utilized and the catalysts activity can be enhanced. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.
基金support from the National Natural Science Foundation of China(Nos.51932001,51872024,52022097,22293043)the National Key Research and Development Program of China(No.2018YFA0703503)the Foundation of the Youth Innovation Promotion Association of Chinese Academy of Sciences(No.2020048)。
文摘Single-atom catalysts(SACs)with high catalytic activity as well as great stability are demonstrating great promotion in electrocatalytic energy conversion,which is also a big challenge to achieve.Herein,we proposed a facile synthetic strategy to construct nickel-iron bimetallic hydroxide nanoribbon stabilized single-atom iridium catalysts(Ir-NiFe-OH),where the nickel-iron hydroxide nanoribbon not only can serve as good electronic conductor,but also can well stabilize and fully expose single-atom sites.Adopted as catalyst for urea oxidation reaction(UOR),it exhibited excellent UOR performance that it only needed a low operated potential of 1.38 V to achieve the current density of 100 mA·cm^(-2).In-situ Fourier transform infrared spectroscopy,X-ray absorption spectrum,and density functional theory calculations proved that Ir species are active centers and the existence of both Ni and Fe in the local structure of Ir atom can optimize the d-band center of Ir species,promoting the adsorption of intermediates and desorption of products for UOR.The hydrogen evolution reaction(HER)/UOR electrocatalytic cell demanded voltages of 1.46 and 1.50 V to achieve 50 and 100 mA·cm^(-2),respectively,which demonstrated a higher activity and better stability than those of conventional catalysts.This work opens a new avenue to develop catalysts for UORs with boosted activity and stability.