Formic acid oxidation reaction(FAOR),as the anodic reaction in direct formic acid fuel cells,has attracted much attention but increasing the mass activity and stability of catalysts still face a bottleneck to meet the...Formic acid oxidation reaction(FAOR),as the anodic reaction in direct formic acid fuel cells,has attracted much attention but increasing the mass activity and stability of catalysts still face a bottleneck to meet the requirements of practical applications.In the past decades,researchers developed many strategies to fix these issues by improving the structure of catalysts and the newly raised single atom catalysts(SACs)show the high mass activity and stability in FAOR.This review first summarized the reaction mechanism involved in FAOR.The mass activity as well as stability of catalysts reported in the past five years have been outlined.Moreover,the synthetic strategies to improve the catalytic performance of catalysts are also reviewed in this work.Finally,we proposed the research directions to guide the rational design of new FAOR catalysts in the future.展开更多
Nanoporous Pd and binary Pd-Cu particles were prepared by a hydrothermal method using ethylene glycol as a reduction agent and they were directly immobilized on Ti substrates named as Ti-supported Pd-based catalysts. ...Nanoporous Pd and binary Pd-Cu particles were prepared by a hydrothermal method using ethylene glycol as a reduction agent and they were directly immobilized on Ti substrates named as Ti-supported Pd-based catalysts. Their electrocatalytic activity for formic acid oxidation and oxygen reduction reaction （ORR） in alkaline media was examined by voltammetric techniques. Among the as-prepared catalysts, nanoPdslCu19/Ti catalyst presents the highest current density of 39.8 mA/cm2 at -0.5 V or 66.4 mA/cm2 at -0.3 V for formic acid oxidation. The onset potential of ORR on the nanoPdslCU19/Ti catalyst presents an about 70 mV positive shift compared to that on the nanoPd/Ti, and the current density of ORR at -0.3 V is 2.12 mA/cm2, which is 3.7 times larger than that on the nanoPd/Ti.展开更多
A carbon supported Pd（Pd/C） catalyst used as the anodic catalyst in the direct formic acid fuel cells（DFAFC） was prepared via the improved complex reduction method with sodium ethylenediamine tetracetate（EDTA） a...A carbon supported Pd（Pd/C） catalyst used as the anodic catalyst in the direct formic acid fuel cells（DFAFC） was prepared via the improved complex reduction method with sodium ethylenediamine tetracetate（EDTA） as stabilizer and complexing agent. This method is very simple. The average size of the Pd particles in the Pd/C catalyst prepared with the improved complex reduction method is as small as about 2.1 nm and the Pd particles in the Pd/C catalyst possess an excellent uniformity. The Pd/C catalyst shows a high electrocatalytic activity and stability for the formic acid oxidation.展开更多
Rational synthesis of a new class of electrocatalysts with high-performance and low-cost is of great significance for future fuel cell devices. Herein, we demonstrate a general one-step simultaneous reduction method t...Rational synthesis of a new class of electrocatalysts with high-performance and low-cost is of great significance for future fuel cell devices. Herein, we demonstrate a general one-step simultaneous reduction method to prepare carbon-supported Pd M（M = Co, Fe, Ni） alloyed nanodendrites with the assistance of oleylamine and octadecylene. The morphology, structure and composition of the obtained Pd M nanodendrites/C catalysts have been fully characterized. The combination of the dendritic structural feature and alloyed synergy offer higher atomic utilization efficiency, excellent catalytic activity and enhanced stability for the formic acid oxidation reaction（FAOR）. Strikingly, the as-synthesized Pd Co nanodendrites/C catalyst could afford a mass current density of 2467.7 A g, which is almost 3.53 and 10.4 times higher than those of lab-made Pd/C sample(698.3 A g) and commercial Pd/C catalyst(237.6 A g), respectively. Furthermore, the PdC o nanodendrites/C catalyst also exhibit superior stability relative to the Pd/C catalysts, make it a promising anodic electrocatalyst in practical fuel cells in the future. Additionally, the present feasible synthetic approach is anticipated to provide a versatile strategy toward the preparation of other metal alloy nanodendrites/carbon nanohybrids.展开更多
Highly active and durable electrocatalytic materials towards small molecules electro-oxidation reaction are critical to the large-scale commercial applications of direct liquid fuel cells.Unfortunately,current nanocry...Highly active and durable electrocatalytic materials towards small molecules electro-oxidation reaction are critical to the large-scale commercial applications of direct liquid fuel cells.Unfortunately,current nanocrystalline electrocatalysts normally suffer from low catalytic efficiency,severe CO poisoning and rapid activity decay.Herein,we report a novel amorphous Pd Ni Cu P catalyst synthesized with laser liquid ablation as a potential settlement to this issue.The as-obtained amorphous Pd Ni Cu P catalyst exhibits enhanced electrocatalytic performance with the mass activity of 1.61 A mg^(-1)and 737.8 m A mg^(-1)towards methanol oxidation reaction(MOR)and formic acid oxidation reaction(FAOR),respectively.Moreover,amorphous Pd Ni Cu P displays excellent operation stability and CO-poisoning resistance in both alkaline and acidic medium.P was proposed to play the decisive role for forming the amorphous structure and maintaining the catalytic stability in MOR and FAOR processes.This work provided insights for the ration design of active and durable amorphous electrocatalysts applied in direct liquid fuel cells.展开更多
Concave nanostructures may be developed to improve the specific mass activity of a catalyst for formic acid and methanol electro-oxidation. In this work, we report the elctrocatalytic oxidation of methanol and formic ...Concave nanostructures may be developed to improve the specific mass activity of a catalyst for formic acid and methanol electro-oxidation. In this work, we report the elctrocatalytic oxidation of methanol and formic acid in acid medium over concave Pt-Cu-Fe ternary nanocubes（NCs）, obtained by the galvanic exchange of Pt and Fe on Cu NCs. The concave Pt-Cu-Fe NCs exhibited improved electrooxidation performance contrasted to Pt-Cu NCs and purchased commercial Pt/C as demonstrated by their improved durability, lower onset potential, and more preferable anti-poisoning properties. These properties are believed to originate from the tailored concave structure of the catalyst and possible synergetic effects among the components of the Pt-Cu-Fe NCs.展开更多
The kinetics of formic acid oxidation (FAO) on Pd(111) in 0.1 mol/L H2SO4+0.1 mol/L HCOOH with and without addition of Na2SO4 is studied using cyclic voltammetry and potential step method, which is compared with that ...The kinetics of formic acid oxidation (FAO) on Pd(111) in 0.1 mol/L H2SO4+0.1 mol/L HCOOH with and without addition of Na2SO4 is studied using cyclic voltammetry and potential step method, which is compared with that in 0.1 mol/L HClO4. It is found that adsorbed sulfate has significant inhibition effect on FAO kinetics. After addition of 0.05 mol/L or 0.1 mol/L Na2SO4, FAO current in the negative-going scan is found to be significantly smaller than that at the same potential in the positive-going scan. We speculate that at potentials positive of the phase transition potential for the (SO4*ad)m+[(H2O)n-H3O+] or(SO4*ad)m+[Na+(H2O)n-H3O+] adlayer, the adlayer structure probably becomes denser and more stable with the increase of potential or with the addition of Na2SO4. The formation of connected adlayer network greatly enhance the stability of the adlayer, and the insertion of positive-charged H+ or Na+ into the adlayer network further reduces the electrostatic repulsion between partially charged sulfates. As a result, the destruction/desorption of compact sulfate adlayer becomes more difficult, which leaves much less free sites on the surface for FAO, and thus FAO kinetics at higher potentials and in the subsequent negative-going potential scan is significantly inhibited.展开更多
A novel ternary nanocomposite, Pd nanoparticles（NPs）/polyoxometalates（POMs）/reduced graphene oxide（rGO）, was prepared by a green, mild, electrochemical-reductionassisted assembly. It is worth noting that the Keg...A novel ternary nanocomposite, Pd nanoparticles（NPs）/polyoxometalates（POMs）/reduced graphene oxide（rGO）, was prepared by a green, mild, electrochemical-reductionassisted assembly. It is worth noting that the Keggin-type POM acts as an electrocatalyst as well as a bridging molecule. During the reduction process, POMs transfer the electrons from the electrode to GO, leading to a deep reduction of GO and the content of oxygen-containing groups is decreased to around 6.1%. Meanwhile, the strong adsorption effect between the POM clusters and rGO nanosheets induces the spontaneous assembly of POM on r GO in a uniformly dispersed state, forming a nanocomposite. The ternary Pd NPs/POMs/rGO nanocomposite exhibits higher electrocatalytic activities, better electrochemical stability, and higher resistance to CO poisoning than the Pd/C catalyst towards the formic acid oxidation（FAOR）. Especially, the Pd/PW（12）/rGO exhibits the best electrocatalytic performance among three Pd/POMs/rGO composites（POMs = PW（12）, SiW（12）, PMo（12））.展开更多
Crystallographic defects in noble metal nanocrystals are recognized as highly active catalytic sites,significantly enhancing activities in many important reactions.Despite their importance,synthesizing noble metal nan...Crystallographic defects in noble metal nanocrystals are recognized as highly active catalytic sites,significantly enhancing activities in many important reactions.Despite their importance,synthesizing noble metal nanocrystals with a high density of defects poses a considerable synthetic challenge.Here,we present a novel lattice mismatch-induced formation mechanism to create high-density defects in noble metal nanocrystals.This approach takes advantage of lattice mismatch to enable nonepitaxial nucleation and growth of a noble metal on a foreign metal substrate,forming abundant noble metal crystallites with random lattice orientations not dictated by the substrate lattice.As these crystallites grow extensively,they merge,forming numerous grain boundaries and yielding defect-rich noble metal nanocrystals.Defect-rich alloy nanocrystals can also be synthesized through a subsequent vacancy-diffusion alloying process.We take defective PdCu alloy nanocages as an example and demonstrate the effectiveness of crystallographic defects in enhancing catalytic performance of noble metal nanocrystals.The nanocages exhibit superior activity in the electrocatalytic formic acid oxidation reaction,which is 1.6 times greater than their defect-free counterparts.Our strategy offers a new avenue for creating defect-rich noble metal nanocrystals as highly efficient catalysts for a wide array of catalytic applications.展开更多
To efficiently diminish the Pt consumption while concurrently enhancing the anodic reaction kinetics,a straightforward synthesis for PtPdAg nanotrees(NTs)with exceedingly low Pt content is presented,utilizing the galv...To efficiently diminish the Pt consumption while concurrently enhancing the anodic reaction kinetics,a straightforward synthesis for PtPdAg nanotrees(NTs)with exceedingly low Pt content is presented,utilizing the galvanic replacement reaction between the initially prepared PdAg NTs and Pt ions.Due to the multilevel porous tree-like structure and the incorporation of low amounts of Pt,the electrocatalytic activity and stability of PtPdAg NTs are markedly enhanced,achieving 1.65 and 1.69 A·mg^(-1)Pt+Pd for the anodic reactions of formic acid oxidation(FAOR)and methanol oxidation(MOR)within DLFCs,surpassing the performance of PdAg NTs,as well as that of commercial Pt and Pd black.Density functional theory(DFT)calculations reveal that the addition of low amounts of Pt leads to an increase in the d-band center of PtPdAg NTs and lower the COads adsorption energy to-1.23 eV,enhancing the anti-CO toxicity properties optimally.This approach offers an effective means for designing low Pt catalysts as exceptional anodic electrocatalysts for direct liquid fuel cells.展开更多
Direct formic acid fuel cells are promising energy devices with advantages of low working temperature and high safety in fuel storage and transport.They have been expected to be a future power source for portable elec...Direct formic acid fuel cells are promising energy devices with advantages of low working temperature and high safety in fuel storage and transport.They have been expected to be a future power source for portable electronic devices.The technology has been developed rapidly to overcome the high cost and low power performance that hinder its practical application,which mainly originated from the slow reaction kinetics of the formic acid oxidation and complex mass transfer within the fuel cell electrodes.Here,we provide a comprehensive review of the progress around this technology,in particular for addressing multiscale challenges from catalytic mechanism understanding at the atomic scale,to catalyst design at the nanoscale,electrode structure at the micro scale and design at the millimeter scale,and finally to device fabrication at the meter scale.The gap between the highly active electrocatalysts and the poor electrode performance in practical devices is highlighted.Finally,perspectives and opportunities are proposed to potentially bridge this gap for further development of this technology.展开更多
The mechanism and kinetics of electrocatalytic oxidation of formic acid at Pt electrodes is discussed in detail based on previous electrochemical in-situ ATR-FTIRS data [Langmuir 22, 10399 （2006）and Angewa. Chem. In...The mechanism and kinetics of electrocatalytic oxidation of formic acid at Pt electrodes is discussed in detail based on previous electrochemical in-situ ATR-FTIRS data [Langmuir 22, 10399 （2006）and Angewa. Chem. Int. Ed. 50, 1159 （2011）]. A kinetic model with formic acid adsorption （and probably the simultaneous C-H bond activation） as the rate determining step, which contributes to the majority of reaction current for formic acid oxi- dation, was proposed for the direct pathway. The model simulates well the IR spectroscopic results obtained under conditions where the poisoning effect of carbon monoxide （CO） is negligible and formic acid concentration is below 0.1 mol/L. The kinetic simulation predicts that in the direct pathway formic acid oxidation probably only needs one Pt atom as active site, formate is the site blocking species instead of being the active intermediate. We review in detail the conclusion that formate pathway （with either 1st or 2nd order reaction kinetics） is the direct pathway, possible origins for the discrepancies are pointed out.展开更多
To address the insufficient electrocatalytic activity and stability of formic acid oxidation reaction （FAOR） electrocatalysts, as well as their high cost, we herein demonstrate the facile hydrothermal synthesis of u...To address the insufficient electrocatalytic activity and stability of formic acid oxidation reaction （FAOR） electrocatalysts, as well as their high cost, we herein demonstrate the facile hydrothermal synthesis of ultrathin AgPt alloy nanowires using amine-terminated poly（N-isopropylacrylamide） （PNIPAM-NH2） as a structure-directing agent. The initial generation of AgC1 precipitates, subsequent formation of AgPt nanoparticles, and their oriented attachment account for the formation of ultrathin AgPt alloy nanowires. Benefiting from their unique one-dimensional （1D） anisotropy and alloyed composition, the prepared ultrathin AgPt nanowires exhibit a superior electrocatalytic activity and better CO tolerance for the FAOR, reaching a 1.6-fold and 3.7-fold higher specific current density than AgPt nanoparticles and a commercial Pt black catalyst, respectively. Additionally, the ultrathin AgPt alloy nanowires manifest a superior electrochemical stability and structural robustness during electrocatalysis, making them a promising FAOR electrocatalyst. This work not only provides a reliable strategy for the synthesis of noble metal-based ultrathin nanowires, but also opens an avenue towards the rational des ign of efficient electrocatalysts for fuel cell systems.展开更多
A novel carbon-supported cyanogel （C@cyanogel）-derived strategy is used to synthesize an intermetallic Pd3Fe/C compound of the desired ordered Pd3Fe phase with a small particle size. The novelty of this work lies in...A novel carbon-supported cyanogel （C@cyanogel）-derived strategy is used to synthesize an intermetallic Pd3Fe/C compound of the desired ordered Pd3Fe phase with a small particle size. The novelty of this work lies in using carbon- supported K2PdHCl4/K4Fe^Ⅱ（CN）6 cyanogel as a reaction precursor, generated through the substitution of two chloride ligands by the nitrogen ends of the cyanide ligands on the metal center. The inherent nature of cyanogels can effectively suppress the movement of Pd^0 and Fe^0 nuclei in the crystal, benefiting the formation of the intermetallic, which is otherwise challenging via traditional synthesis techniques. The ordered Pd3Fe/C catalyst exhibits excellent catalytic activity and good cycle stability for the formic acid oxidation （FAO） reaction relative to the properties of disordered Pd3Fe/C and commercial Pd/C catalysts, dernonstrating that the ordered Pd3Fe/C is a promising replacement for commercial Pd-based catalysts. The outstanding performance can be ascribed to the full isolation of active sites in the ordered Pd3Fe structure and the modified electronic structure of the active components. This work provides an effective and novel route to obtain Pd-based intermetallic compounds with potential applications in a wide range of electrocatalysis.展开更多
The development of an efficient catalyst for formic acid electrocatalytic oxidation reaction(FAEOR)is of great significance to accelerate the commercial application of direct formic acid fuel cells(DFAFC).Herein,palla...The development of an efficient catalyst for formic acid electrocatalytic oxidation reaction(FAEOR)is of great significance to accelerate the commercial application of direct formic acid fuel cells(DFAFC).Herein,palladium phosphide(PdxPy)porous nanotubes(PNTs)with different phosphide content(i.e.,Pd3P and Pd5P2)are prepared by combining the self-template reduction method of dimethylglyoxime-Pd(II)complex nanorods and succedent phosphating treatment.During the reduction process,the self-removal of the template and the continual inside-outside Ostwald ripening phenomenon are responsible for the generation of the one-dimensional hollow and porous architecture.On the basis of the unique synthetic procedure and structural advantages,Pd3P PNTs with optimized phos phide content show outstanding electroactivity and stability for FAEOR.Im portantly,the strong electronic effect between Pd and P promotes the direct pathway of FAEOR and inhibits the occurrence of the formic acid decomposition reaction,which effectively enhances the FAEOR electroactivity of Pd3P PNTs.In view of the facial synthesis,excellent electroactivity,high stability,and unordinary selectivity,Pd3P PNTs have the potential to be an efficient anode electrocatalyst for DFAFC.展开更多
Anti-CO poisoning ability is significant in formic acid oxidation in the fuel cell technique.Herein,Pd Ni alloy supported on N-doped graphene aerogel(Pd Ni/GA-N)was found to have catalytic ability toward formic acid e...Anti-CO poisoning ability is significant in formic acid oxidation in the fuel cell technique.Herein,Pd Ni alloy supported on N-doped graphene aerogel(Pd Ni/GA-N)was found to have catalytic ability toward formic acid electrooxidation over a wide potential range because of the improved anti-CO poisoning ability.This catalyst was fabricated by simple freeze-drying of mixture solution of graphene aerogel,polyvinylpyrrolidone,Pd^(2+)and Ni^(2+)and the subsequent thermal annealing reduction approach in the N2/H2 atmosphere.Pd-Ni alloy particles anchored over the folding N-doped graphene surface with a porous hierarchical architecture structure in the 3 D directions.It showed the catalytic performance of its maximum mass activity of 836 m A mg^(-1)in a broad potential range(0.2-0.6 V)for formic acid oxidation.The CO stripping experiment demonstrated its largely improved anti-CO poisoning ability with the peak potential of 0.67 V,approximately 60 and 40 m V less compared to those of Pd/GA-N and Pd/C samples.The high anti-CO poisoning ability and strong electronic effect resulting from the interaction between the3 D GA-N support and the Pd-Ni alloy makes it a promising catalyst for application in direct formic acid fuel cells.展开更多
Combinations of graphene(Gr)and carbon black(C)were employed as binary carbon supports to fabricate Pd‐based electrocatalysts via one‐pot co‐reduction with Pd2+.The electrocatalytic performance of the resulting Pd...Combinations of graphene(Gr)and carbon black(C)were employed as binary carbon supports to fabricate Pd‐based electrocatalysts via one‐pot co‐reduction with Pd2+.The electrocatalytic performance of the resulting Pd/Gr‐C catalysts during the electrooxidation of formic acid was assessed.A Pd/Gr0.3C0.7(Gr oxide:C=3:7,based on the precursor mass ratio)electrocatalyst exhibited better catalytic performance than both Pd/C and Pd/Gr catalysts.The current density generated by the Pd/Gr0.3C0.7catalyst was as high as102.14mA mgPd?1,a value that is approximately3times that obtained from the Pd/C(34.40mA mgPd?1)and2.6times that of the Pd/Gr material(38.50mA mgPd?1).The anodic peak potential of the Pd/Gr0.3C0.7was120mV more negative than that of the Pd/C and70mV more negative than that of the Pd/Gr.Scanning electron microscopy images indicated that the spherical C particles accumulated on the wrinkled graphene surfaces to form C cluster/Gr hybrids having three‐dimensional nanostructures.X‐ray photoelectron spectroscopy data confirmed the interaction between the Pd metal and the binary Gr‐C support.The Pd/Gr0.3C0.7also exhibited high stability,and so is a promising candidate for the fabrication of anodes for direct formic acid fuel cells.This work demonstrates a simple and cost‐effective method for improving the performance of Pd‐based electrocatalysts,which should have potential industrial applications.展开更多
Pt：Pd：Co ternary alloy nanoparticles were synthesized by sodium borohydride reduction under nitrogen, and were supported on carbon black as catalysts for methanol and formic acid electro-oxidation. Compared with Pt0...Pt：Pd：Co ternary alloy nanoparticles were synthesized by sodium borohydride reduction under nitrogen, and were supported on carbon black as catalysts for methanol and formic acid electro-oxidation. Compared with Pt0.65C00.35/C, Pt/C, Pd0.65C00.35/C, and Pd/C catalyst, Pt0.35Pd0.35Co0.30/C exhibited relatively high durability and strong poisoning resistance, and the Pt-mass activity was 3.6 times higher than that of Pt/C in methanol oxidation reaction. Meanwhile, the Pt0.35Pd0.35Co0.30/C exhibited excellent activity with higher current density and higher CO tolerance than that of Pt0.6sCo0.35/C, Pt/C, Pd0.65C00.35/ C, and Pd/C in formic acid electro-oxidation.展开更多
Direct formic acid fuel cell(DFAFC) is an important research project in clean energy field.However,commercialization of DFAFC is still largely limited by the available catalysts with unsatisfied activity,durability an...Direct formic acid fuel cell(DFAFC) is an important research project in clean energy field.However,commercialization of DFAFC is still largely limited by the available catalysts with unsatisfied activity,durability and cost for formic acid electrooxidation(FAEO).Using Pt-and Pd-based nanoclusters as electrocatalysts is a particularly promising strategy to solve the above problem,but two attendant problems need to be solved firstly.(Ⅰ) The controllable synthesis of practicable and stable sub-2 nm clusters remains challenging.(Ⅱ) The catalyzing mechanism of sub-2 nm metal clusters for FAEO has not yet completely understood.Herein,different from traditional solution synthesis,by designing a novel supporting material containing electron-rich and electron-deficient functional groups,size-and dispersioncontrollable synthesis of ~1 nm PtPd nanoclusters is realized by an electrochemical process.The electrocatalytic properties and reaction mechanism of the PtPd nanoclusters for the FAEO were studied by different electrochemical techniques,in-situ fourier transform infrared(FTIR) spectra and density functional theory(DFT) calculations.The tiny PtPd nanoclusters have much higher catalytic activity and durability than commercial Pt/C,Pd/C and 3.5 nm PtPd nanoparticles.The present study shows that the metalreactant interaction plays a decisive role in determining the catalytic activity and cluster-support interaction plays a decisive role in enhancing the durability of electrocatalyst.The ratio and arrangement of Pt and Pd atoms on the surface of 1 nm PtPd cluster as well as the overall valence state,d-band center and specific surface area make them exhibit different catalytic performance and reaction mechanism from nanoparticle catalysts.In addition,in situ FTIR and DFT calculations showed that on the surface of PtPd clusters,the generation of CO_(2)through trans-COOH intermediate is the most optimal reaction pathway for the FAEO.展开更多
Formic acid oxidation(FAO)is a typical anode reaction in fuel cells that can be facilitated by modulating its direct and indirect reaction pathways.Herein,PtAu bimetallic nanoparticles loaded onto Co and N co-doping c...Formic acid oxidation(FAO)is a typical anode reaction in fuel cells that can be facilitated by modulating its direct and indirect reaction pathways.Herein,PtAu bimetallic nanoparticles loaded onto Co and N co-doping carbon nanoframes(CoNC NFs)were designed to improve the selectivity of the direct reaction pathway for efficient FAO.Based on these subtle nanomaterials,the influences of elemental composition and carbon-support materials on the two pathways of FAO were investigated in detail.The results of fuel cell tests verified that the appropriate amount of Au in PtAu/CoNC can promote a direct reaction pathway for FAO,which is crucial for enhancing the oxidation efficiency of formic acid.In particular,the obtained PtAu/CoNC with an optimal Pt/Au atomic ratio of 1:1(PtAu/CoNC-3)manifests the best catalytic performance among the analogous obtained Pt-based electrocatalysts.The FAO mass activity of the PtAu/CoNC-3 sample reached 0.88 A·mg_(Pt)^(-1),which is 26.0 times higher than that of Pt/C.The results of first-principles calculation and CO stripping jointly demonstrate that the CO adsorption of PtAu/CoNC is considerably lower than that of Pt/CoNC and PtAu/C,which indicates that the synergistic effect of Pt,Au,and CoNC NFs is critical for the resistance of Pt to CO poisoning.This work is of great significance for a deeper understanding of the oxidation mechanism of formic acid and provides a feasible and promising strategy for enhancing the catalytic performance of the catalyst by improving the direct reaction pathway for FAO.展开更多
基金Project(22102218)supported by the National Natural Science Foundation of ChinaProject(2022RC1110)supported by the Science and Technology Innovation Program of Hunan Province,ChinaProject(2022QNRC001)supported by the Young Elite Scientists Sponsorship Program by CAST,China。
文摘Formic acid oxidation reaction(FAOR),as the anodic reaction in direct formic acid fuel cells,has attracted much attention but increasing the mass activity and stability of catalysts still face a bottleneck to meet the requirements of practical applications.In the past decades,researchers developed many strategies to fix these issues by improving the structure of catalysts and the newly raised single atom catalysts(SACs)show the high mass activity and stability in FAOR.This review first summarized the reaction mechanism involved in FAOR.The mass activity as well as stability of catalysts reported in the past five years have been outlined.Moreover,the synthetic strategies to improve the catalytic performance of catalysts are also reviewed in this work.Finally,we proposed the research directions to guide the rational design of new FAOR catalysts in the future.
基金Project(10JJ9003) supported by Hunan Provincial Natural Science Foundation and Xiangtan Natural Science United Foundation,China Project(11K023) supported by Scientific Research Fund of Hunan Provincial Education Department,China
文摘Nanoporous Pd and binary Pd-Cu particles were prepared by a hydrothermal method using ethylene glycol as a reduction agent and they were directly immobilized on Ti substrates named as Ti-supported Pd-based catalysts. Their electrocatalytic activity for formic acid oxidation and oxygen reduction reaction （ORR） in alkaline media was examined by voltammetric techniques. Among the as-prepared catalysts, nanoPdslCu19/Ti catalyst presents the highest current density of 39.8 mA/cm2 at -0.5 V or 66.4 mA/cm2 at -0.3 V for formic acid oxidation. The onset potential of ORR on the nanoPdslCU19/Ti catalyst presents an about 70 mV positive shift compared to that on the nanoPd/Ti, and the current density of ORR at -0.3 V is 2.12 mA/cm2, which is 3.7 times larger than that on the nanoPd/Ti.
基金Supported by the "863" Program of Science and Technology Ministry of China(Nos.2006AA05Z137, 2007AA05Z143 and 2007AA05Z159)National Natural Science Foundation of China(Nos.20433060, 20473038, 20573057 and 20703043)the Natural Science Foundation of Jiangsu Province, China(No.BK2006224).
文摘A carbon supported Pd（Pd/C） catalyst used as the anodic catalyst in the direct formic acid fuel cells（DFAFC） was prepared via the improved complex reduction method with sodium ethylenediamine tetracetate（EDTA） as stabilizer and complexing agent. This method is very simple. The average size of the Pd particles in the Pd/C catalyst prepared with the improved complex reduction method is as small as about 2.1 nm and the Pd particles in the Pd/C catalyst possess an excellent uniformity. The Pd/C catalyst shows a high electrocatalytic activity and stability for the formic acid oxidation.
基金financial supports from NSFC(no.21576139,21503111 and 21376122)Natural Science Foundation of Jiangsu Province(BK20171473)+2 种基金Natural Science Foundation of Jiangsu Higher Education Institutions of China(16KJB150020)National and Local Joint Engineering Research Center of Biomedical Functional Materialsa project sponsored by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Rational synthesis of a new class of electrocatalysts with high-performance and low-cost is of great significance for future fuel cell devices. Herein, we demonstrate a general one-step simultaneous reduction method to prepare carbon-supported Pd M（M = Co, Fe, Ni） alloyed nanodendrites with the assistance of oleylamine and octadecylene. The morphology, structure and composition of the obtained Pd M nanodendrites/C catalysts have been fully characterized. The combination of the dendritic structural feature and alloyed synergy offer higher atomic utilization efficiency, excellent catalytic activity and enhanced stability for the formic acid oxidation reaction（FAOR）. Strikingly, the as-synthesized Pd Co nanodendrites/C catalyst could afford a mass current density of 2467.7 A g, which is almost 3.53 and 10.4 times higher than those of lab-made Pd/C sample(698.3 A g) and commercial Pd/C catalyst(237.6 A g), respectively. Furthermore, the PdC o nanodendrites/C catalyst also exhibit superior stability relative to the Pd/C catalysts, make it a promising anodic electrocatalyst in practical fuel cells in the future. Additionally, the present feasible synthetic approach is anticipated to provide a versatile strategy toward the preparation of other metal alloy nanodendrites/carbon nanohybrids.
基金supported by the National Natural Science Foundation of China(Nos.52177220,52001219 and U1601216)。
文摘Highly active and durable electrocatalytic materials towards small molecules electro-oxidation reaction are critical to the large-scale commercial applications of direct liquid fuel cells.Unfortunately,current nanocrystalline electrocatalysts normally suffer from low catalytic efficiency,severe CO poisoning and rapid activity decay.Herein,we report a novel amorphous Pd Ni Cu P catalyst synthesized with laser liquid ablation as a potential settlement to this issue.The as-obtained amorphous Pd Ni Cu P catalyst exhibits enhanced electrocatalytic performance with the mass activity of 1.61 A mg^(-1)and 737.8 m A mg^(-1)towards methanol oxidation reaction(MOR)and formic acid oxidation reaction(FAOR),respectively.Moreover,amorphous Pd Ni Cu P displays excellent operation stability and CO-poisoning resistance in both alkaline and acidic medium.P was proposed to play the decisive role for forming the amorphous structure and maintaining the catalytic stability in MOR and FAOR processes.This work provided insights for the ration design of active and durable amorphous electrocatalysts applied in direct liquid fuel cells.
文摘Concave nanostructures may be developed to improve the specific mass activity of a catalyst for formic acid and methanol electro-oxidation. In this work, we report the elctrocatalytic oxidation of methanol and formic acid in acid medium over concave Pt-Cu-Fe ternary nanocubes（NCs）, obtained by the galvanic exchange of Pt and Fe on Cu NCs. The concave Pt-Cu-Fe NCs exhibited improved electrooxidation performance contrasted to Pt-Cu NCs and purchased commercial Pt/C as demonstrated by their improved durability, lower onset potential, and more preferable anti-poisoning properties. These properties are believed to originate from the tailored concave structure of the catalyst and possible synergetic effects among the components of the Pt-Cu-Fe NCs.
基金supported by the National Natural Science Foundation of China(No.21872132 and No.21832004)973 Program from the Ministry of Science and Technology of China(No.201503932301)
文摘The kinetics of formic acid oxidation (FAO) on Pd(111) in 0.1 mol/L H2SO4+0.1 mol/L HCOOH with and without addition of Na2SO4 is studied using cyclic voltammetry and potential step method, which is compared with that in 0.1 mol/L HClO4. It is found that adsorbed sulfate has significant inhibition effect on FAO kinetics. After addition of 0.05 mol/L or 0.1 mol/L Na2SO4, FAO current in the negative-going scan is found to be significantly smaller than that at the same potential in the positive-going scan. We speculate that at potentials positive of the phase transition potential for the (SO4*ad)m+[(H2O)n-H3O+] or(SO4*ad)m+[Na+(H2O)n-H3O+] adlayer, the adlayer structure probably becomes denser and more stable with the increase of potential or with the addition of Na2SO4. The formation of connected adlayer network greatly enhance the stability of the adlayer, and the insertion of positive-charged H+ or Na+ into the adlayer network further reduces the electrostatic repulsion between partially charged sulfates. As a result, the destruction/desorption of compact sulfate adlayer becomes more difficult, which leaves much less free sites on the surface for FAO, and thus FAO kinetics at higher potentials and in the subsequent negative-going potential scan is significantly inhibited.
基金financially supported by the National Natural Science Foundation of China(No.21571034)the Natural Science Foundation of Fujian Province(No.2014J01033)a Key Item of Education Department of Fujian Province(No.JA13085)
文摘A novel ternary nanocomposite, Pd nanoparticles（NPs）/polyoxometalates（POMs）/reduced graphene oxide（rGO）, was prepared by a green, mild, electrochemical-reductionassisted assembly. It is worth noting that the Keggin-type POM acts as an electrocatalyst as well as a bridging molecule. During the reduction process, POMs transfer the electrons from the electrode to GO, leading to a deep reduction of GO and the content of oxygen-containing groups is decreased to around 6.1%. Meanwhile, the strong adsorption effect between the POM clusters and rGO nanosheets induces the spontaneous assembly of POM on r GO in a uniformly dispersed state, forming a nanocomposite. The ternary Pd NPs/POMs/rGO nanocomposite exhibits higher electrocatalytic activities, better electrochemical stability, and higher resistance to CO poisoning than the Pd/C catalyst towards the formic acid oxidation（FAOR）. Especially, the Pd/PW（12）/rGO exhibits the best electrocatalytic performance among three Pd/POMs/rGO composites（POMs = PW（12）, SiW（12）, PMo（12））.
基金support of the National Natural Science Foundation of China(22371222)the Science Fund for Distinguished Young Scholars of Shaanxi Province(2024JC-JCQN-14)+4 种基金the Key Research and Development Projects of Shaanxi Province(2021GXLHZ-022)the Fundamental Research Funds for Central Universities.Z.L.acknowledges the support from the China Postdoctoral Science Foundation(2023TQ0263)the National Postdoctoral Research Program of China(GZC20232091)the Postdoctoral Research Project of Shaanxi Province(2023BSHYDZZ49)the Fundamental Research Funds for the Central Universities(XZY012023026).
文摘Crystallographic defects in noble metal nanocrystals are recognized as highly active catalytic sites,significantly enhancing activities in many important reactions.Despite their importance,synthesizing noble metal nanocrystals with a high density of defects poses a considerable synthetic challenge.Here,we present a novel lattice mismatch-induced formation mechanism to create high-density defects in noble metal nanocrystals.This approach takes advantage of lattice mismatch to enable nonepitaxial nucleation and growth of a noble metal on a foreign metal substrate,forming abundant noble metal crystallites with random lattice orientations not dictated by the substrate lattice.As these crystallites grow extensively,they merge,forming numerous grain boundaries and yielding defect-rich noble metal nanocrystals.Defect-rich alloy nanocrystals can also be synthesized through a subsequent vacancy-diffusion alloying process.We take defective PdCu alloy nanocages as an example and demonstrate the effectiveness of crystallographic defects in enhancing catalytic performance of noble metal nanocrystals.The nanocages exhibit superior activity in the electrocatalytic formic acid oxidation reaction,which is 1.6 times greater than their defect-free counterparts.Our strategy offers a new avenue for creating defect-rich noble metal nanocrystals as highly efficient catalysts for a wide array of catalytic applications.
基金supported by the National Natural Science Foundation of China(Nos.22202104,22279062,22232004 and 22072067)the Natural Science Foundation of Jiangsu Province(No.BK20220933)Shuangchuang Doctor Plan of Jiangsu Province(No.JSSCBS20220273).
文摘To efficiently diminish the Pt consumption while concurrently enhancing the anodic reaction kinetics,a straightforward synthesis for PtPdAg nanotrees(NTs)with exceedingly low Pt content is presented,utilizing the galvanic replacement reaction between the initially prepared PdAg NTs and Pt ions.Due to the multilevel porous tree-like structure and the incorporation of low amounts of Pt,the electrocatalytic activity and stability of PtPdAg NTs are markedly enhanced,achieving 1.65 and 1.69 A·mg^(-1)Pt+Pd for the anodic reactions of formic acid oxidation(FAOR)and methanol oxidation(MOR)within DLFCs,surpassing the performance of PdAg NTs,as well as that of commercial Pt and Pd black.Density functional theory(DFT)calculations reveal that the addition of low amounts of Pt leads to an increase in the d-band center of PtPdAg NTs and lower the COads adsorption energy to-1.23 eV,enhancing the anti-CO toxicity properties optimally.This approach offers an effective means for designing low Pt catalysts as exceptional anodic electrocatalysts for direct liquid fuel cells.
基金sponsored by a PhD Scholarship from the School of Chemical Engineering at the University of Birminghamsupported by EU H2020-MSCAIF-2019 project EconCell 898486
文摘Direct formic acid fuel cells are promising energy devices with advantages of low working temperature and high safety in fuel storage and transport.They have been expected to be a future power source for portable electronic devices.The technology has been developed rapidly to overcome the high cost and low power performance that hinder its practical application,which mainly originated from the slow reaction kinetics of the formic acid oxidation and complex mass transfer within the fuel cell electrodes.Here,we provide a comprehensive review of the progress around this technology,in particular for addressing multiscale challenges from catalytic mechanism understanding at the atomic scale,to catalyst design at the nanoscale,electrode structure at the micro scale and design at the millimeter scale,and finally to device fabrication at the meter scale.The gap between the highly active electrocatalysts and the poor electrode performance in practical devices is highlighted.Finally,perspectives and opportunities are proposed to potentially bridge this gap for further development of this technology.
基金This work was supported by one hundred Tal- ents＇ Program of the Chinese Academy of Science, the National Natural Science Foundation of China （No.21273215）, 973 program from the Ministry of Sci- ence and Technology of China （No.2010CB923302）.
文摘The mechanism and kinetics of electrocatalytic oxidation of formic acid at Pt electrodes is discussed in detail based on previous electrochemical in-situ ATR-FTIRS data [Langmuir 22, 10399 （2006）and Angewa. Chem. Int. Ed. 50, 1159 （2011）]. A kinetic model with formic acid adsorption （and probably the simultaneous C-H bond activation） as the rate determining step, which contributes to the majority of reaction current for formic acid oxi- dation, was proposed for the direct pathway. The model simulates well the IR spectroscopic results obtained under conditions where the poisoning effect of carbon monoxide （CO） is negligible and formic acid concentration is below 0.1 mol/L. The kinetic simulation predicts that in the direct pathway formic acid oxidation probably only needs one Pt atom as active site, formate is the site blocking species instead of being the active intermediate. We review in detail the conclusion that formate pathway （with either 1st or 2nd order reaction kinetics） is the direct pathway, possible origins for the discrepancies are pointed out.
文摘To address the insufficient electrocatalytic activity and stability of formic acid oxidation reaction （FAOR） electrocatalysts, as well as their high cost, we herein demonstrate the facile hydrothermal synthesis of ultrathin AgPt alloy nanowires using amine-terminated poly（N-isopropylacrylamide） （PNIPAM-NH2） as a structure-directing agent. The initial generation of AgC1 precipitates, subsequent formation of AgPt nanoparticles, and their oriented attachment account for the formation of ultrathin AgPt alloy nanowires. Benefiting from their unique one-dimensional （1D） anisotropy and alloyed composition, the prepared ultrathin AgPt nanowires exhibit a superior electrocatalytic activity and better CO tolerance for the FAOR, reaching a 1.6-fold and 3.7-fold higher specific current density than AgPt nanoparticles and a commercial Pt black catalyst, respectively. Additionally, the ultrathin AgPt alloy nanowires manifest a superior electrochemical stability and structural robustness during electrocatalysis, making them a promising FAOR electrocatalyst. This work not only provides a reliable strategy for the synthesis of noble metal-based ultrathin nanowires, but also opens an avenue towards the rational des ign of efficient electrocatalysts for fuel cell systems.
文摘A novel carbon-supported cyanogel （C@cyanogel）-derived strategy is used to synthesize an intermetallic Pd3Fe/C compound of the desired ordered Pd3Fe phase with a small particle size. The novelty of this work lies in using carbon- supported K2PdHCl4/K4Fe^Ⅱ（CN）6 cyanogel as a reaction precursor, generated through the substitution of two chloride ligands by the nitrogen ends of the cyanide ligands on the metal center. The inherent nature of cyanogels can effectively suppress the movement of Pd^0 and Fe^0 nuclei in the crystal, benefiting the formation of the intermetallic, which is otherwise challenging via traditional synthesis techniques. The ordered Pd3Fe/C catalyst exhibits excellent catalytic activity and good cycle stability for the formic acid oxidation （FAO） reaction relative to the properties of disordered Pd3Fe/C and commercial Pd/C catalysts, dernonstrating that the ordered Pd3Fe/C is a promising replacement for commercial Pd-based catalysts. The outstanding performance can be ascribed to the full isolation of active sites in the ordered Pd3Fe structure and the modified electronic structure of the active components. This work provides an effective and novel route to obtain Pd-based intermetallic compounds with potential applications in a wide range of electrocatalysis.
基金supported by the National Natural Science Foundation of China(21875133 and 51873100)Natural Science Foundation of Shaanxi Province(2020JZ-23)+2 种基金the National Training Program of Innovation and Entrepreneurship for Undergraduates(S202010718130)Fundamental Research Funds for the Central Universities(GK202101005,GK202103062,and 2021CBLZ004)the 111 Project(B14041).
文摘The development of an efficient catalyst for formic acid electrocatalytic oxidation reaction(FAEOR)is of great significance to accelerate the commercial application of direct formic acid fuel cells(DFAFC).Herein,palladium phosphide(PdxPy)porous nanotubes(PNTs)with different phosphide content(i.e.,Pd3P and Pd5P2)are prepared by combining the self-template reduction method of dimethylglyoxime-Pd(II)complex nanorods and succedent phosphating treatment.During the reduction process,the self-removal of the template and the continual inside-outside Ostwald ripening phenomenon are responsible for the generation of the one-dimensional hollow and porous architecture.On the basis of the unique synthetic procedure and structural advantages,Pd3P PNTs with optimized phos phide content show outstanding electroactivity and stability for FAEOR.Im portantly,the strong electronic effect between Pd and P promotes the direct pathway of FAEOR and inhibits the occurrence of the formic acid decomposition reaction,which effectively enhances the FAEOR electroactivity of Pd3P PNTs.In view of the facial synthesis,excellent electroactivity,high stability,and unordinary selectivity,Pd3P PNTs have the potential to be an efficient anode electrocatalyst for DFAFC.
基金supported by the National Natural Science Foundation of China(21972124,21603041)a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institution+1 种基金the Double Tops Joint Fund of the Yunnan Science and Technology Bureau and Yunnan University(2019FY003025)the Research Foundation of Department of Education of Yunnan Province(2020Y0018)。
文摘Anti-CO poisoning ability is significant in formic acid oxidation in the fuel cell technique.Herein,Pd Ni alloy supported on N-doped graphene aerogel(Pd Ni/GA-N)was found to have catalytic ability toward formic acid electrooxidation over a wide potential range because of the improved anti-CO poisoning ability.This catalyst was fabricated by simple freeze-drying of mixture solution of graphene aerogel,polyvinylpyrrolidone,Pd^(2+)and Ni^(2+)and the subsequent thermal annealing reduction approach in the N2/H2 atmosphere.Pd-Ni alloy particles anchored over the folding N-doped graphene surface with a porous hierarchical architecture structure in the 3 D directions.It showed the catalytic performance of its maximum mass activity of 836 m A mg^(-1)in a broad potential range(0.2-0.6 V)for formic acid oxidation.The CO stripping experiment demonstrated its largely improved anti-CO poisoning ability with the peak potential of 0.67 V,approximately 60 and 40 m V less compared to those of Pd/GA-N and Pd/C samples.The high anti-CO poisoning ability and strong electronic effect resulting from the interaction between the3 D GA-N support and the Pd-Ni alloy makes it a promising catalyst for application in direct formic acid fuel cells.
基金supported by the Natural Science Foundation of Shandong Province(ZR2016BM31)the Science and Technology Foundation of Jinan City(201311035)~~
文摘Combinations of graphene(Gr)and carbon black(C)were employed as binary carbon supports to fabricate Pd‐based electrocatalysts via one‐pot co‐reduction with Pd2+.The electrocatalytic performance of the resulting Pd/Gr‐C catalysts during the electrooxidation of formic acid was assessed.A Pd/Gr0.3C0.7(Gr oxide:C=3:7,based on the precursor mass ratio)electrocatalyst exhibited better catalytic performance than both Pd/C and Pd/Gr catalysts.The current density generated by the Pd/Gr0.3C0.7catalyst was as high as102.14mA mgPd?1,a value that is approximately3times that obtained from the Pd/C(34.40mA mgPd?1)and2.6times that of the Pd/Gr material(38.50mA mgPd?1).The anodic peak potential of the Pd/Gr0.3C0.7was120mV more negative than that of the Pd/C and70mV more negative than that of the Pd/Gr.Scanning electron microscopy images indicated that the spherical C particles accumulated on the wrinkled graphene surfaces to form C cluster/Gr hybrids having three‐dimensional nanostructures.X‐ray photoelectron spectroscopy data confirmed the interaction between the Pd metal and the binary Gr‐C support.The Pd/Gr0.3C0.7also exhibited high stability,and so is a promising candidate for the fabrication of anodes for direct formic acid fuel cells.This work demonstrates a simple and cost‐effective method for improving the performance of Pd‐based electrocatalysts,which should have potential industrial applications.
基金supported by NSFC(No.21373116)Tianjin Natural Science Research Fund(No.13JCYBJC18300)+1 种基金RFDP(No. 20120031110005)MOE Innovation Team of China(No. IRT13022)
文摘Pt：Pd：Co ternary alloy nanoparticles were synthesized by sodium borohydride reduction under nitrogen, and were supported on carbon black as catalysts for methanol and formic acid electro-oxidation. Compared with Pt0.65C00.35/C, Pt/C, Pd0.65C00.35/C, and Pd/C catalyst, Pt0.35Pd0.35Co0.30/C exhibited relatively high durability and strong poisoning resistance, and the Pt-mass activity was 3.6 times higher than that of Pt/C in methanol oxidation reaction. Meanwhile, the Pt0.35Pd0.35Co0.30/C exhibited excellent activity with higher current density and higher CO tolerance than that of Pt0.6sCo0.35/C, Pt/C, Pd0.65C00.35/ C, and Pd/C in formic acid electro-oxidation.
基金supported by the National Key Research and Development Plan(2020YFB1506001)the Natural Science Foundation of Guangxi Province(2019GXNSFGA245003)+1 种基金the National Natural Science Foundation of China(Nos.22272036,21575134,21773224)the Guangxi Normal University Research Grant(2022TD)。
文摘Direct formic acid fuel cell(DFAFC) is an important research project in clean energy field.However,commercialization of DFAFC is still largely limited by the available catalysts with unsatisfied activity,durability and cost for formic acid electrooxidation(FAEO).Using Pt-and Pd-based nanoclusters as electrocatalysts is a particularly promising strategy to solve the above problem,but two attendant problems need to be solved firstly.(Ⅰ) The controllable synthesis of practicable and stable sub-2 nm clusters remains challenging.(Ⅱ) The catalyzing mechanism of sub-2 nm metal clusters for FAEO has not yet completely understood.Herein,different from traditional solution synthesis,by designing a novel supporting material containing electron-rich and electron-deficient functional groups,size-and dispersioncontrollable synthesis of ~1 nm PtPd nanoclusters is realized by an electrochemical process.The electrocatalytic properties and reaction mechanism of the PtPd nanoclusters for the FAEO were studied by different electrochemical techniques,in-situ fourier transform infrared(FTIR) spectra and density functional theory(DFT) calculations.The tiny PtPd nanoclusters have much higher catalytic activity and durability than commercial Pt/C,Pd/C and 3.5 nm PtPd nanoparticles.The present study shows that the metalreactant interaction plays a decisive role in determining the catalytic activity and cluster-support interaction plays a decisive role in enhancing the durability of electrocatalyst.The ratio and arrangement of Pt and Pd atoms on the surface of 1 nm PtPd cluster as well as the overall valence state,d-band center and specific surface area make them exhibit different catalytic performance and reaction mechanism from nanoparticle catalysts.In addition,in situ FTIR and DFT calculations showed that on the surface of PtPd clusters,the generation of CO_(2)through trans-COOH intermediate is the most optimal reaction pathway for the FAEO.
基金support from the National Natural Science Foundation of China(Nos.51801188,12034002,and 51971025)the China Postdoctoral Science Foundation(No.2018M632792)+3 种基金program for the Innovation Team of Science and Technology in University of Henan(No.20IRTSTHN014)Excellent Youth Foundation of Henan Scientific Committee(No.202300410356)the CAS Interdisciplinary Innovation Team(No.JCTD-2019-01)Beijing Natural Science Foundation(No.2204085)。
文摘Formic acid oxidation(FAO)is a typical anode reaction in fuel cells that can be facilitated by modulating its direct and indirect reaction pathways.Herein,PtAu bimetallic nanoparticles loaded onto Co and N co-doping carbon nanoframes(CoNC NFs)were designed to improve the selectivity of the direct reaction pathway for efficient FAO.Based on these subtle nanomaterials,the influences of elemental composition and carbon-support materials on the two pathways of FAO were investigated in detail.The results of fuel cell tests verified that the appropriate amount of Au in PtAu/CoNC can promote a direct reaction pathway for FAO,which is crucial for enhancing the oxidation efficiency of formic acid.In particular,the obtained PtAu/CoNC with an optimal Pt/Au atomic ratio of 1:1(PtAu/CoNC-3)manifests the best catalytic performance among the analogous obtained Pt-based electrocatalysts.The FAO mass activity of the PtAu/CoNC-3 sample reached 0.88 A·mg_(Pt)^(-1),which is 26.0 times higher than that of Pt/C.The results of first-principles calculation and CO stripping jointly demonstrate that the CO adsorption of PtAu/CoNC is considerably lower than that of Pt/CoNC and PtAu/C,which indicates that the synergistic effect of Pt,Au,and CoNC NFs is critical for the resistance of Pt to CO poisoning.This work is of great significance for a deeper understanding of the oxidation mechanism of formic acid and provides a feasible and promising strategy for enhancing the catalytic performance of the catalyst by improving the direct reaction pathway for FAO.
