-proline assisted solvothermal preparation of Cu-rich rhombic dodecahedral PtCu nanoframes as advanced electrocatalysts for oxygen reduction and hydrogen evolution reactions

Solvothermal Fabrication of Mesoporous Pd Nano-Corals at Mild Temperature for Alkaline Hydrogen Evolution Reaction

Porous metallic nanomaterials exhibit interesting physical and chemical properties, and are widely used in various fields. Traditional fabrication techniques are limited to metallurgy, sintering, electrodeposition, etc., which limit the control of pore size and distribution, and make it difficult to achieve materials with high surface areas. On the other hand, the chemical preparation of metallic nanoparticles is usually carried out with strong reducing agents or at high temperature, resulting in the formation of dispersed particles which cannot evolve into porous metal. In this study, we reported the simple fabrication of coral-like mesoporous Pd nanomaterial (Pd NC) with a ligament size of 4.1 nm. The fabrication was carried out by simple solvothermal reduction at a mild temperature of 135 °C, without using any templates. The control experiments suggested that tetrabutylammonium bromide (TBAB) played a critical role in the Pd(II) reduction into Pd nanoclusters and their subsequent aggregation to form Pd NC, and another key point for the formation of Pd NC is not to use a strong reducing agent. In alkaline water electrolysis, the Pd NC outperforms the monodisperse Pd NPs and the state-of-the-art Pt (under large potentials) for H2 evolution reaction, probably due to its mesoporous structure and large surface area. This work reports a simple and novel method for producing porous metallic nanomaterials with a high utilization efficiency of metal atoms, and it is expected to contribute to the practical preparation of porous metallic nanomaterials by solvothermal reductions.

New Approach to Synthesizing Cathode PtCo/C Catalysts for Low-Temperature Fuel Cells

The presented study is concerned with a new multi-step method to synthesize PtCo/C materials based on composite CoxOy/C that combines the advantages of different liquid-phase synthesis methods. Based on the results of studying the materials at each stage of synthesis with the TG, XRD, TEM, SEI, TXRF, CV and LSV methods, a detailed overview of the sequential changes in catalyst composition and structure at each stage of the synthesis is presented. The PtCo/C catalyst synthesized with the multi-step method is characterized by a uniform distribution of bimetallic nanoparticles of about 3 nm in size over the surface of the support, which result in its high ESA and ORR activity. The activity study for the synthesized PtCo/C catalyst in an MEA showed better current-voltage characteristics and a higher maximum specific power compared with an MEA based on a commercial Pt/C catalyst. Therefore, the results of the presented study demonstrate high prospects for the developed approach to the multi-step synthesis of PtM/C catalysts, which may enhance the characteristics of proton-exchange membrane fuel cells (PEMFCs).

Transition metal-based electrocatalysts for alkaline overall water splitting: advancements, challenges, and perspectives

Water electrolysis is a promising method for efficiently producing hydrogen and oxygen, crucial for renewable energy conversion and fuel cell technologies. The hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are two key electrocatalytic reactions occurring during water splitting, necessitating the development of active, stable, and low-cost electrocatalysts. Transition metal (TM)-based electrocatalysts, spanning noble metals and TM oxides, phosphides, nitrides, carbides, borides, chalcogenides, and dichalcogenides, have garnered significant attention due to their outstanding characteristics, including high electronic conductivity, tunable valence electron configuration, high stability, and cost-effectiveness. This timely review discusses developments in TM-based electrocatalysts for the HER and OER in alkaline media in the last 10 years, revealing that the exposure of more accessible surface-active sites, specific electronic effects, and string effects are essential for the development of efficient electrocatalysts towards electrochemical water splitting application. This comprehensive review serves as a guide for designing and constructing state-of-the-art, high-performance bifunctional electrocatalysts based on TMs, particularly for applications in water splitting.

Progress in electrocatalytic hydrogen evolution of transition metal alloys: synthesis, structure, and mechanism analysis

At present, the problems of high energy consumption and low efficiency in electrocatalytic hydrogen production have limited the large-scale industrial application of this technology. Constructing effective catalysts has become the way to solve these problems. Transition metal alloys have been proved to be very promising materials in hydrogen evaluation reaction (HER). In this study, the related theories and characterization methods of electrocatalysis are summarized, and the latest progress in the application of binary, ternary, and high entropy alloys to HER in recent years is analyzed and studied. The synthesis methods and optimization strategies of transition metal alloys, including composition regulation, hybrid engineering, phase engineering, and morphological engineering were emphatically discussed, and the principles and performance mechanism analysis of these strategies were discussed in detail. Although great progress has been made in alloy catalysts, there is still considerable room for applications. Finally, the challenges, prospects, and research directions of transition metal alloys in the future were predicted.

Nucleation and growth mechanism of dendrite-free Ni–Cu catalysts by magneto-electrodeposition for the hydrogen evolution reaction

A controllable preparation strategy for high-efficiency Ni–Cu catalysts with specific morphology.

Evolution of PtCu tripod nanocrystals to dendritic triangular nanocrystals and study of the electrochemical performance to alcohol electrooxidation

In the field of catalysis, the design and construction of nanomaterials is an efficient way to optimize the catalytic activity of catalysts. This study presents the synthesis of PtCu tripod nanocrystals with branching structures and high purity prepared using a simple hydrothermal method. The dendritic PtCu triangular nanocrystals were successfully synthesized by regulating the amount of I^- ions to achieve different degrees of branching on PtCu nanocrystals, and the process was systematically studied and analyzed. Meanwhile, dumbbell nanocrystals of PtCu were successfully synthesized through slight adjustments to synthesis conditions. In electrochemical tests, the obtained dendritic PtCu triangular nanocrystals exhibited prominent electrocatalytic activity and long-term stability for ethylene glycol, methanol, and ethanol oxidation reactions due to the unique nanostructures as well as alloyed virtue, and were much better than commercial Pt/C. In addition, this study provides a general strategy for designing novel branched Pt-based nanomaterials with high electrocatalytic performance.

A facile strategy synthesized PtRhNi truncated triangle nanoflakes with PtRh-rich surface as highly active and stable bifunctional catalysts for direct methanol fuel cells

Committed to improving the utilization efficiency of Pt atoms and accurately controlling the morphology and composition of nanocatalysts to boost the Pt-based catalyst performance has become the focus of research. Herein, the PtRhNi truncated triangular nanoflakes (TA-NFs) catalyst with a unique PtRh-rich surface structure was successfully prepared by an effective one-pot synthetic method based on the galvanic replace reaction. The freestanding 2D nanostructure of PtRhNi TA-NFs, intrinsically possessing much high specific surface area and surface atomic, and the PtRh-rich characteristics of the surface is undoubtedly the most feasible model to simultaneously achieve high atom utilization. Benefiting from this novel structure, the as-obtained PtRhNi TA-NFs nanocatalyst exhibits excellent performance for ORR and MOR, delivering a mass activity of 0.92 A mg_pt^-1 for ORR, which is 2.03, 1.64, and 6.9-fold higher than that of PtRhNi nanoparticls (NPs), PtNi truncated triangle nanoflakes (TA-NFs) and commercial Pt/C, respectively. In addition, after 20 k cycles ADT test, PtRhNi TA-NFs show only 10 mV negative shift of half-wave potential and retain 70% of initial value of mass activity. Furthermore, a mass activity is 1.28 A mg_pt^-1 is achieved after applying this unique nanocatalyst for MOR, which is 1.28,1.5, and 2.6 times higher than that of PtRhNi NPs, PtNi TA-NFs and Pt/C, respectively. Impressively, the PtRhNi TA-NFs nanocatalyst shows an ultrahigh stability even after 2 k cycles ADT measurement in acid solution, and the mass activity is only drop 2% of initial value. This work provides a new strategy to synthesis high-performance of bifunction Pt-based electrocatalyst for ORR and MOR fuel cells.

Recent Advances in Amino-Based Molecules Assisted Control of Noble-Metal Electrocatalysts

Morphology-control synthesis is an effective means to tailor surface structure of noble-metal nanocrystals, which offers a sensitive knob for tuning their electrocatalytic properties. The functional molecules are often indispensable in the morphology-control synthesis through preferential adsorption on specific crystal facets, or controlling certain crystal growth directions. In this review, the recent progress in morphology-control synthesis of noble-metal nanocrystals assisted by amino-based functional molecules for electrocatalytic applications are focused on. Although a mass of noble-metal nanocrystals with different morphologies have been reported, few review studies have been published related to amino-based molecules assisted control strategy. A full understanding for the key roles of amino-based molecules in the morphology-control synthesis is still necessary. As a result, the explicit roles and mechanisms of various types of amino-based molecules, including amino-based small molecules and amino-based polymers, in morphology-control of noble-metal nanocrystals are summarized and discussed in detail. Also presented in this progress are unique electrocatalytic properties of various shaped noble-metal nanocrystals. Particularly, the optimization of electrocatalytic selectivity induced by specific amino-based functional molecules (e.g., polyallylamine and polyethyleneimine) is highlighted. At the end, some critical prospects, and challenges in terms of amino-based molecules-controlled synthesis and electrocatalytic applications are proposed.

A monodispersed CuPt alloy: synthesis and its superior catalytic performance in the hydrogen evolution reaction over a full pH range

The high cost and low stability of electrocatalysts are the major challenges for the commercialization of hydrogen generation in water. In this study, we demonstrated a one-pot synthesis of a monodispersed CuPt alloy with the diameter range of 20–30 nm by a hydrothermal method. Benefiting from the more available active sites and preferable d-band structure, the CuPt alloy exhibited a superior catalytic performance than pure Pt nanoparticles (Pt NPs) in the hydrogen evolution reaction (HER). In acidic media, the CuPt alloy achieved a low overpotential of 39 mV at a current density of 10 mA cm⁻² for HER, which was by 22 mV lower than that for pure Pt NPs. In a neutral solution, the stability of the CuPt alloy is ca. 100-fold as compared to pure Pt NPs. Accounting by the dissolution of Cu in the alloy phase, the performance of the CuPt alloy was elevated after yielding hydrogen for 1.2 × 10⁵ s in alkaline media. The superior catalytic activity can also be applied in other applications. In the reduction of 4-nitro-phenol (4-NP), the CuPt alloy showed 12.84-fold catalytic activity higher than pure Pt NPs. This study designed a low-cost electrocatalyst with an efficient and durable catalytic performance for HER over the full pH range, which provides an environmentally friendly strategy to cope with the challenges of hydrogen generation.

An effective approach to achieve the low cost and high stability of electro-catalysts for HER.

Potentiostatic electrodeposition of Ni-Se-Cu on nickel foam as an electrocatalyst for hydrogen evolution reaction

Development of cost-effective and efficient earth-abundant catalysts for hydrogen evolution reaction (HER) is a great challenge. In this study, by one-step potentiostatic electrodeposition, the Ni-Se-Cu electrocatalyst on nickel foam was fabricated as a binder-free HER electrocatalyst. As compared with Ni-Se electrocatalysts, such fabricated Ni-Se-Cu electrocatalyst exhibited prominent electrocatalytic activity to the HER in alkaline electrolyte. This Ni-Se-Cu electrocatalyst exhibits a small overpotential of 136 mV to achieve a current density of 10 mA·cm^-2 and high electrochemical stability. The remarkable HER properties of Ni-Se-Cu electrocatalyst mainly originate from high electronic conductivity induced by Cu-doping. This work shows a cheap and simple avenue to develop high efficient non-noble electrochemical electrocatalysts for HER.

Ultrafast and surfactant-free synthesis of Sub-3 nm nanoalloys by shear-assisted liquid-metal reduction

The uniform and surfactant-free synthesis of ultrafine alloy nanoparticles (NPs) still remains an ongoing challenge. Here, we developed a general route for synthesizing sub-3 nm nanoalloys on a carbon support via a shear-assisted liquid-metal reduction (SA-LMR) strategy. The utilization of shearing treatment resulted in the rapid release of electrons from the liquid sodium-potassium (NaK) alloy, which enabled the ultrafast reduction of precursor metal ions to metallic nanoalloys at room temperature. As a model system, Pt-Cu NPs with uniform distribution were synthesized and characterized by spectroscopic and microscopic techniques. The size, composition and structure of the Pt-Cu NPs could be tuned by controlling the volume of liquid NaK alloy and the reaction time. To prove the universality and utility of our method, the binary Pt-M (Fe, Co, Ni, and Cu) and ternary Pt-Cu-Fe nanoalloys deposited on a carbon support were prepared as hydrogen evolution reaction (HER) catalysts. This facile, rapid and universal synthesis technique has the potential to be employed in the large-scale production of nanomaterials and suggests a new direction for nanoalloys.

Catalytic Nanoframes and Beyond

The ever-increasing need for the production and expenditure of sustainable energy is a result of the astonishing rate of consumption of fossil fuels and the accompanying environmental problems. Emphasis is being directed to the generation of sustainable energy by the fuel cell and water splitting technologies. Accordingly, the development of highly efficient electrocatalysts has attracted significant interest, as the fuel cell and water splitting technologies are critically dependent on their performance. Among numerous catalyst designs under investigation, nanoframe catalysts have an intrinsically large surface area per volume and a tunable composition, which impacts the number of catalytically active sites and their intrinsic catalytic activity, respectively. Nevertheless, the structural integrity of the nanoframe during electrochemical operation is an ongoing concern. Some significant advances in the field of nanoframe catalysts have been recently accomplished, specifically geared to resolving the catalytic stability concerns and significantly boosting the intrinsic catalytic activity of the active sites. Herein, general synthetic concepts of nanoframe structures and their structure-dependent catalytic performance are summarized, along with recent notable advances in this field. A discussion on the remaining challenges and future directions, addressing the limitations of nanoframe catalysts, are also provided.

Tiny Ir doping of sub-one-nanometer PtMn nanowires: highly active and stable catalysts for alcohol electrooxidation

One-dimensional (1D) Pt-based nanowires (NWs) materials serve as efficient catalysts for alcohol electrocatalysis. However, precisely tailoring their size towards sub-one-nanometer scale has been verified as an effective method for enhancing electrocatalytic properties, which is rarely studied. In this work, we developed a one-pot simple yet efficient method for synthesizing a kind of sub-one-nanometer tiny Ir-doped PtMn NWs. The prepared PtMnIr NWs have an ultrathin structure with a mean diameter of around only 0.97 nm (about 3-5 atomic thickness), which display large surface areas and promote superficial Pt atom utilization. With the robust tiny Ir incorporation, the composition-optimized Pt74Mn21Ir5 NWs showed enhanced mass activity, which was 1.51 and 1.53 times higher than those of non-Ir-doped Pt79Mn21 NWs for acidic ethanol oxidation reaction (EOR) and methanol oxidation reaction (MOR). Moreover, benefiting from the atom-level ultrathin size and well-tuned ligand effect from Ir to PtMn, the EOR/MOR mass activities of sub-nanometric Pt74Mn21Ir5 NWs were 3.99- and 3.98-fold higher than those of Pt/C catalysts. More importantly, after successive EOR and MOR CV tests, the Ir-doped PtMn NWs still maintained 85.6% and 73.4% of the initial mass activity, which were much better than those of Pt79Mn21 NWs, Pt NWs, and Pt/C catalysts. This work could be extended to engineering other advanced materials with super sub-one-nanometer structure, which is beneficial for largely improving the catalytic performance.

Segmentation and Re-encapsulation of Porous PtCu Nanoparticles by Generated Carbon Shell for Enhanced Ethylene Glycol Oxidation and Oxygen-Reduction Reaction

Hierarchical porous carbon-encapsulated ultrasmall PtCu (UsPtCu@C) nanoparticles (NPs) were constructed based on segmentation and re-encapsulation of porous PtCu NPs by using glucose as a green biomass carbon source. The synergistic electronic effect from the bimetallic elements can enhance the catalytic activity by adjusting the surface electronic structure of Pt. Most importantly, the generated porous carbon shell provided a large contact surface area, excellent electrical conductivity, and structural stability, and the ultrasmall PtCu NPs exhibited an increased electrochemical performance compared with their PtCu matrix because of the exposure of more catalytically active centers. This synergistic relationship between the components resulted in enhanced catalytic activity and better stability of the obtained UsPtCu@C for ethylene glycol oxidation reaction and the oxygen-reduction reaction in alkaline electrolyte, which was higher than the PtCu NPs and commercial Pt/C (20 wt % Pt on Vulcan XC-72). The electrochemically active surface areas of the UsPtCu@C, PtCu NPs, and commercial Pt/C were calculated to be approximately 230.2, 32.8, and 64.0 m²/g_Pt, respectively; the mass activity of the UsPtCu@C for the ethylene glycol oxidation reaction was 8.5 A/mg_Pt, which was 14.2 and 8.5 times that of PtCu NPs and commercial Pt/C, respectively. The specific activity of UsPtCu@C was 3.7 mA/cm_pt², which was 2.1 and 2.3 times that of PtCu NPs and commercial Pt/C, respectively. The onset potential (E_on-set) of UsPtCu@C for the oxygen-reduction reaction was 0.96 V (vs reversible hydrogen electrode, RHE), which was 110 and 60 mV higher than PtCu and commercial Pt/C, respectively. The half-wave potentials (E_1/2) of UsPtCu@C, PtCu, and Pt/C were 0.88, 0.56, and 0.82 V (vs RHE), respectively, which indicated that the UsPtCu@C catalyst had an excellent bifunctional electrocatalytic activity.

Facile Synthesis Of Composition-Controllable PtPdAuTe Nanowires As Superior Electrocatalysts For Direct Methanol Fuel Cells

Multicomponent Pt-based nanowires (NWs) have attracted widespread attention as eletrocatalysts toward direct alcohol fuel cells because of their unique one-dimensional structure and high reaction dynamics. Quaternary PtPdAuTe NWs are designed via a facile template method, and NWs with a different composition are obtained by adjusting the feed ratio of metal precursors. The direct displacement reaction of metal precursors with Te NWs and the partial oxidation of Te lead to the formation of quaternary NWs. The rough surface and abundant reactive sites deriving from the rearrangement of metal atoms on the Te NWs surface endow the PtPdAuTe NWs with a superior electrocatalytic property and durability for methanol oxidation. The Pt₂₀ Pd₂₀ Au₁₀ Te₅₀ NWs display the largest mass activity and best stability among all catalysts. The preparation of PtPdAuTe NWs could provide a viable strategy for the preparation of other multicomponent NWs.

PtMn/PtCo alloy nanofascicles: robust electrocatalysts for electrocatalytic hydrogen evolution reaction under both acidic and alkaline conditions

Herein, PtMn and PtCo nanofascicles were prepared by ultrathin nanofibers using a versatile method, and can be employed as effective electrocatalysts toward the HER under both acidic and alkaline conditions.

Ultrathin PdFePb nanowires: One-pot aqueous synthesis and efficient electrocatalysis for polyhydric alcohol oxidation reaction

Synthesis of high-efficiency catalysts for alcohol oxidation reaction caused great interest in direct alcohol fuel cells (DAFCs). Ultrathin PdFePb nanowires (NWs) with an average diameter of 2.3 nm were synthesized by a simple and fast one-pot aqueous synthesis, using octylphenoxypolyethoxyethanol (NP-40) as the structure-directing agent. The as-prepared PdFePb NWs displayed an increscent electrochemically active surface area (ECSA, 121.18 m² g^-1 _Pd). For ethylene glycol oxidation reaction (EGOR) and glycerol oxidation reaction (GOR), PdFePb NWs exhibited much higher activity and superior stability, outperforming those of homemade PdFe NWs, PdPb NWs, commercial Pd black and Pd/C (20 wt%). These results reveal dramatically high catalytic activity and durability of ultrathin PdFePb NWs in enhancing polyols electrooxidation.

Graphene wrapped Fe7C3 nanoparticles supported on N-doped graphene nanosheets for efficient and highly methanol-tolerant oxygen reduction reaction

Green and efficient non-precious metal electrocatalysts for oxygen reduction reaction (ORR) are prepared to meet the increasing demand for clean, secure and sustainable energy. Herein, we report a novel and environmentally friendly strategy for synthesis of graphene-wrapped iron carbide (Fe₇C₃) nanoparticles supported on hierarchical fibrous N-doped graphene with open-mesoporous structures (Fe₇C₃/NG) by simply annealing the mixture of melamine, iron (II) phthalocyanine (FePc) and Fe₂O₃. The effects of the pyrolysis temperature and the molar ratio of FePc to melamine were critically examined in the controls. Remarkably, the Fe₇C₃/NG obtained at 800 °C (i.e. Fe₇C₃/NG-800) manifested the forward shifts in the onset potential (0.98 V) and half-wave potential (0.85 V) with respective to commercial Pt/C (50 wt%) in 0.1 M KOH, coupled with the great enhancement in the durability (still remained 92.11% of its initial current density even after 40,000 s) and strong methanol tolerance. This research presents a promising strategy for developing Pt-free non-precious efficient ORR electrocatalysts in fuel cells.

Highly dispersive NiCo2S4 nanoparticles anchored on nitrogen-doped carbon nanofibers for efficient hydrogen evolution reaction

To solve the energy crisis problem, many efforts have been devoted to develop clean and sustainable alternatives to fossil fuels. Among varieties of pathways to obtain clean energy, electrochemical water splitting is a promising approach. Herein, we had successfully synthesized the NiCo₂S₄@porous nitrogen-doped carbon nanofibers (NiCo₂S₄@NCNF) nanocomposite via three successive steps consisted of in-situ oxidative polymerization, calcination, and solvothermal sulfuration reaction processes. The effect of controlled molar ratios to electrocatalytic performance was studied in detail. The optimized NiCo₂S₄@NCNF nanocomposite exhibits superior electrocatalytic activity for hydrogen evolution reaction with a small overpotential of 117 mV to drive a current density of 10 mA cm^-2. More importantly, it exhibits similar electrocatalytic activity to the initial state even after successive cyclic voltammetry scan for 3000 cycles, indicating its excellent long-term stability. The superior electrochemical performance is attributed to the developed three-dimensional (3D) network nanostructure derived from bacterial cellulose nanofibers, the highly conductive porous nitrogen-doped carbon nanofibers, and the synergistic effect between metal Ni and Co of NiCo₂S₄. This study permits a new pathway to design efficient electrocatalysts based on eco-friendly materials for the production of clean hydrogen energy.

3D highly branched PtCoRh nanoassemblies: Glycine-assisted solvothermal synthesis and superior catalytic activity for alcohol oxidation

Advanced Pt-based ternary nanocatalysts display dramatically enhanced utilization efficiency of Pt alternative to mono- and bi-counterparts, owing to the synergistic effects of the tri-metals. Herein, multicomponent uniform 3D PtCoRh highly branched nanoassemblies (HBNAs) were prepared by glycine-assisted one-pot solvothermal method in oleylamine (OAm). The effects of the precursor types, reaction time and amount of glycine were critically investigated in this synthesis. The as-prepared PtCoRh HBNAs displayed outstanding electrocatalytic activity and improved stability towards ethanol oxidation reaction (EOR) and methanol oxidation reaction (MOR) in 1 M KOH electrolyte, whose mass/specific activities were 1.75 A mg^-1/4.03 mA cm^-2 and 0.98 A mg^-1/2.34 mA cm^-2, respectively, which were remarkably higher than commercial Pt/C (0.85 A mg^-1/4.03 mA cm^-2 and 0.47 A mg^-1/0.89 mA cm^-2). This study provides some novel guidelines to fabricate advanced multimetallic electrocatalysts for practical applications in direct alcohol fuel cells (DAFCs).

Noble Metal Based Alloy Nanoframes: Syntheses and Applications in Fuel Cells

Noble metal nanostructures are being used broadly as catalysts for energy conversion in fuel cells. To overcome the future energy crises, fuel cells are anticipated as clean energy sources because they can be operated at low temperature, their energy conversion is high and their carbon release is almost zero. However, an active and stable electrocatalyst is essential for the electrochemical reactions in fuel cells. Therefore, properties of the nanostructures greatly depend on the shape of the nanostructures. Individual as well as interaction properties are greatly affected by changes in the surface area of the nanostructures. By shape controlled synthesis, properties of the nanostructures could be further enhanced by increasing the surface area or active sites for electrocatalysts. Therefore, an efficient approach is needed for the fabrication of nanostructures to increase their efficiency, activity, or durability in fuel cells by reducing the usage of noble metals. Different types of hollow nanostructures until now have been prepared including nanoboxes, nanocages, nanoshells, nanoframes (NFs), etc. NFs are the hollow unique three-dimensional structure which have no walls-they only contain corners or edges so they have large surface area. In electrocatalytic reactions, the molecules involved in the reaction can easily reach the inner surface of the nanoframes, thus noble metals' utilization efficiency increases. NFs usually have high surface area, greater morphological and compositional stabilities, allowing them to withstand harsh environmental conditions. By considering the current challenges in fabrication of noble metal based alloy NFs as electrocatalysts, this review paper will highlight recent progress, design, and fabrication of noble metal alloy NFs through different strategies-mainly photocatalytic template, electrodeposition, Kirkendall effect, galvanic replacement, chemical/oxidative etching, combination of both and other methods. Then, electrochemical applications of NFs in fuel cells toward formic acid, methanol, ethanol, oxygen reduction reaction as well as bifunctional catalyst will also be highlighted. Finally, we will summarize different challenges in the fabrication of highly proficient nanocatalysts for the fuel cells with low cost, high efficiency and high durability, which are the major issues for the highly commercial use of fuel cells in the future.