Platinum supported on hydroxyl-grafted poly (3,4-ethylenedioxythiophene)-modified RuCo,N-tridoped bamboo-like carbon nanotubes for direct methanol fuel cell

The development of highly active and efficient heterogeneous catalytic oxidation system has become an attractive research field. In this paper, a catalyst (RuCo/N-CNT@PEDOT-OH/Pt) from platinum nanoparticles (Pt NPs) supported on hydroxyl-grafted poly(3,4-ethylenedioxythiophene) (PEDOT–OH)-modified RuCo, N-tridoped bamboo-like carbon nanotubes (RuCo/N-CNT) are used for direct methanol fuel cell (DMFC). The electrocatalytic activity of RuCo/N-CNT@PEDOT-OH/Pt is systematically compared with RuCo/N-CNT/Pt (Pt NPs supported on RuCo/N-CNT without PEDOT-OH) in the methanol oxidation reaction (MOR). The growth mechanism of carbon nanotubes and the role of heteroatom doping in the electrocatalytic process is explored. The catalysts show excellent electrocatalytic performance with high stability for MOR. It is found that the mass activity (MA) of the RuCo/N-CNT@PEDOT-OH/Pt (1961.3 mA mg^?1_Pt) for MOR was higher than that of RuCo/N-CNT/Pt (1470.1 mA mg^?1_Pt) and the commercial Pt/C catalysts (281.0 mA mg^?1_Pt), indicating the positive effect of the PEDOT-OH in the electrocatalytic MOR. In addition, density functional theory (DFT) calculations verify the possible mechanism pathways of the obtained RuCo/N-CNT@PEDOT-OH/Pt catalyst. This presented catalyst offers new inspiration for designing efficient electrocatalysts for methanol oxidation.     

Lattice-strained Pt nanoparticles anchored on petroleum vacuum residue derived N-doped porous carbon as highly active and durable cathode catalysts for PEMFCs

High cost and poor durability of Pt-based cathode catalysts for oxygen reduction reaction (ORR) severely hamper the popularization of proton exchange membrane fuel cells (PEMFCs). Tailoring carbon support is one of effective strategies for improving the performance of Pt-based catalysts. Herein, petroleum vacuum residue was used as carbon source, and nitrogen-doped porous carbon (N-PPC) was synthesized using a simple template-assisted and secondary calcination method. Small Pt nanoparticles (Pt NPs) with an average particles size of 1.8 nm were in-situ prepared and spread evenly on the N-PPC. Interestingly, the lattice compression (1.08%) of Pt NPs on the N-PPC (Pt/N-PPC) was clearly observed by aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), which was also verified by the shift of (111) crystal plane of Pt on N-PPC to higher angles. The X-ray photoelectron spectroscopy (XPS) results suggest that the N-PPC support had a strong effect on anchoring Pt NPs and endowing surface Pt NPs with lowered d band center. Thus, the Pt/N-PPC as a catalyst simultaneously boosted the ORR activity and durability. The specific activity (SA) and mass activity (MA) of the Pt/N-PPC at 0.9 V reached 0.83 mA cm⁻² and 0.37 A mg_Pt⁻¹, respectively, much higher than those of the commercial Pt/C (0.21 mA cm⁻² and 0.11 A mg_Pt⁻¹) in 0.1 M HClO₄. The half-wave potential (E_1/2) of Pt/N-PPC exhibited only a minimal negative shift of 7 mV after 30,000 accelerated durability tests (ADT) cycles. More importantly, an H₂–O₂ fuel cell with a Pt/N-PPC cathode achieved a power density of 866 mW cm⁻², demonstrating that the prepared catalyst has a promising application potential in working environment of PEMFCs.     

Bimetallic Pt3Mn nanowire network structures with enhanced electrocatalytic performance for methanol oxidation

Pt-based catalysts are still most attractive and could be the major driving force for facile electrochemical reactions in direct methanol fuel cells (DMFCs). In this work, a Pt₃Mn nanowire network structures (NWNs) catalyst was successfully synthesized by a soft template (CTAB) method. The morphology and elemental composition of the Pt₃Mn NWNs were investigated by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma-optical emission spectroscopy (ICP-OES). The electrocatalytic behavior of the synthesized Pt₃Mn NWNs catalyst towards methanol oxidation reaction (MOR) was studied by cyclic voltammetry (CV) and chronoamperometry (CA). The results reveal that the Pt₃Mn NWNs has superior MOR activity and durability compared to Pt NWNs and commercial Pt/C. The mass and specific activities of Pt₃Mn NWNs are 0.843 A mg⁻¹ and 1.8 mA cm⁻² respectively, which are twice that of commercial Pt/C. Additionally, the results of CA test indicate that the Pt₃Mn NWNs possesses better durability than Pt NWNs and commercial Pt/C catalysts in acidic media, which is expected to be a new alternative anode material in DMFCs.     

A general strategy for synthesizing hierarchical architectures assembled by dendritic Pt-based nanoalloys for electrochemical hydrogen evolution

The development of multimetallic Pt-based nanostructures as high-performance cathodic electrocatalysts to be used in water-splitting devices for hydrogen generation is the focus of increasing attention. In this study, a family of hierarchical architectures constructed from dendritic quaternary PtFeRuRh, ternary PtFeRh or PtFeRu and binary PtFe nanoalloys are achieved via a general liquid-phase strategy for hydrogen evolution in alkaline electrolyte. Among them, the PtFeRuRh nanoalloys exhibit the lowest overpotential (20.0 mV at 10 mA cm^?2) and Tafel slope (21.1 mV dec^?1). At a potential of ?0.07 V, the mass activity of the PtFeRuRh nanoalloy is 7.04 A mg_Pt^?1, it is 6.97 times that of commercial Pt/C. The dendritic PtFeRuRh nanoalloys exhibit a negligible decrease in activity after 20 h of continuous testing at 10 mA cm^?2/100 mA cm^?2 and 3000 cyclic voltammetry cycles. In a practical application, the cell voltage of a PtFeRhRu (?) || IrO₂ (+) couple is 1.568 V at 10 mA cm^?2 with almost 100% faradaic efficiency. The turnover frequency of the PtFeRhRu electrocatalyst at 70 mV was 78.5 s^?1, which is 11.71 times as large as that of commercial Pt/C (6.7 s^?1).     

Pt–Co nanoparticles anchored by ZrO2 for highly efficient and durable oxygen reduction reaction in H2-air fuel cells

Synthesis of Pt-based catalysts with high activity and durability for oxygen reduction reaction (ORR) remains a very challenging task in the field of fuel cells. Here, Co-doped Pt nanoparticles (NP) with surface-defect ZrO₂ are supported on the multi-walled carbon nanotubes (MWCNTs) (denoted as Pt–Co + ZrO₂/MWCNTs). The Pt–Co + ZrO₂/MWCNTs displays an ORR mass activity of 0.98 A mg_Pt^?1 at 0.9 V, which is 4.1-fold higher than that of the commercial Pt/C (0.238 A mg_Pt^?1). Further durability test shows that the Pt–Co + ZrO₂/MWCNTs remains nearly unchanged ORR mass activity after 50000 accelerated durability testings (ADTs). Based on the mass performance and surface performance, the fuel cell with Pt–Co + ZrO₂/MWCNTs cathode has far better power performance than that with commercial Pt/C. Moreover, the fuel cell with Pt–Co + ZrO₂/MWCNTs cathode undergo only a 6.1% maximum power loss after 50000 ADTs. However, that with commercial Pt/C cathode after 30000 ADTs has 39.6% maxinum power loss. More impressively, compared to the 220 mV loss of Pt/C after 30000 ADTs, the Pt–Co + ZrO₂/MWCNTs cathode also displays only 20 mV loss at 0.8 A/cm² after 50000 ADTs. The enhanced intrinsic activity of Pt–Co + ZrO₂/MWCNTs may be attributed to the Co-doped Pt NPs and interface effect of Co-doped Pt NPs and surface defect-rich ZrO₂.     

ZIF derived mesoporous carbon frameworks with numerous edges and heteroatom-doped sites to anchor nano-Pt electrocatalyst

We report the use of nitrogen-doped three-dimensional carbon frameworks (N-MCF) to promote the catalytic performance of nano-sized Pt electrocatalyst for the catalysis of oxygen reduction reaction (ORR). The N-MCF, obtained by pyrolysis of zeolitic imidazolate framework, provides abundant edges, defects, and heteroatom-doped sites to anchor Pt nanoparticles, leading to strong Pt-support interaction and excellent particle dispersion within its three-dimensional mass transport channels. Electrochemical results show only 8 mV degradation in the half-wave potential after accelerated durability test for the N-MCF supported Pt catalysts. Meanwhile, the mass activity and specific activity of Pt/N-MFC could reach 246 mA mg⁻¹_Pt and 0.276 mA cm⁻² at 0.90 V_RHE, which is better than that of commercial Pt/C. Moreover, the high Pt utilization of Pt/N-MFC (186 mg _Pt kW⁻¹) could reach 1.9 times than that of fuel cell fabricated with commercial Pt/C cathode.     

Boosting activity and stability by coupling Pt–Ni nanoparticles with La-modified flexible carbon nanofibers for hydrogen evolution reaction

Platinum (Pt) is considered as the most efficient catalyst for hydrogen evolution reaction (HER) with a nearly zero overpotential, but it is limited by the high cost and poor stability. Herein, we report an efficient electrocatalyst of Pt–Ni alloy nanoparticles (NPs) supported on the La-modified flexible carbon nanocomposite fibers (PtNi@La-CNFs) for HER. The rare earth metal oxide in the catalyst has a structure-effect relationship with the carbon fibers to form a flexible fiber membrane. Experimental results show that the macroscopic and microscopic properties of carbon nanocomposite fibers can be optimized by doping La₂O₃, and the Pt–Ni NPs can be anchored effectively. The Pt₁Ni₁@La-CNFs electrocatalyst exhibits a small overpotential of 32 mV to achieve current density of 10 mA cm^?2 with a low Tafel slope of 51 mV dec^?1 in alkaline medium, outperforming that of Pt@La-CNFs and the commercial Pt/C catalyst. This study reveals that the multiple coupling effect of rare earth compound, precious metal, and transition metal in composite catalyst can tailor its the electronic configuration, and results in an enhanced HER performance. This work opens up a novel approach to design high active and low cost Pt-based HER catalysts.     

Facile construction of 3D hyperbranched PtRh nanoassemblies: A bifunctional electrocatalyst for hydrogen evolution and polyhydric alcohol oxidation reactions

Development of highly effective and stable electrocatalysts is urgent for various energy conversion applications. Herein, a facile co-reduction approach was developed to fabricate three-dimensional (3D) hyperbranched PtRh nanoassemblies (NAs) under solvothermal conditions, where creatinine and cetyltrimethylammonium chloride (CTAC) were employed as the structure-directing agents. The as-synthesized nanocatalyst exhibited intriguing catalytic characters for hydrogen evolution reduction (HER) with a low overpotential (20 mV) at 10 mA cm⁻² and a small Tafel slope (49.01 mV dec⁻¹). Meanwhile, the catalyst showed remarkably enlarged mass activity (MA: 2.16/2.02 A mg⁻¹) and specific activity (SA: 4.16/3.88 mA cm⁻²) towards ethylene glycol and glycerol oxidation reactions (EGOR and GOR) alternative to commercial Pt black and homemade Pt₃Rh nanodendrites (NDs), PtRh₃ NDs and Pt nanoparticles (NPs). This method offers a feasible platform to fabricate bifunctional, efficient, durable and cost-effective nanocatalysts with finely engineered structures and morphologies for renewable energy devices.     

Pt and Pt–Ag nanoparticles supported on carbon nanotubes (CNT) for oxygen reduction reaction in alkaline medium

In this work, we investigated the effect of the carbon nanotubes (CNT) as alternative support of cathodes for oxygen reduction reaction (ORR) in alkaline medium. The Pt and Pt–Ag nanomaterials supported on CNT were synthesized by sonochemical method. The crystalline structure, morphology, particle size, dispersion, specific surface area, and composition were investigated by XRD, SEM-EDS, TEM, HR-TEM, N₂ adsorption-desorption and XPS characterization. The electrochemical activity for ORR was evaluated by cyclic voltammetry (CV), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS) in alkaline medium. The electrochemical stability was researched by an accelerated degradation test (ADT). Pt/CNT showed the better electrocatalytic activity towards ORR compared with Pt–Ag/CNT and Pt/C. Pt/CNT exhibited higher specific activity (1.12 mA cm^?2 _Pt) than Pt/C (0.25 mA cm^?2 _Pt) which can be attributed to smaller particle size, Pt-CNT interaction, and Pt load (5 wt%). The Pt monometallic samples supported on CNT and Vulcan showed higher electrochemical stability after ADT than Pt–Ag bimetallic. The ORR activity of all materials synthesized proceeded through a four-electron pathway. Furthermore, the EIS results showed that Pt/CNT exhibited the lower resistance to the transfer electron compared with conventional Pt/C and Pt–Ag/CNT.     

High-performance high-entropy quinary-alloys as anode catalysts for direct ethylene glycol fuel cells

Noble metals are the most commonly used electrocatalysts, but due to the high-cost and scarcity, improving their utilization has become a hot topic. As the Pt-based high-entropy alloy (HEA) can greatly increase the activity of catalyst and increase the utilization of noble metal, herein, a HEA with promising performance in ethylene glycol oxidation reaction (EGOR) is developed. The EGOR results show that, the onset potential of PtPdAuNiCo/C is 0.55 V, which is 20 mV lower than Pt/C (0.57 V) reference. Besides, the PtPdAuNiCo/C exhibits a high activity of 0.482 A mg^?1_PtPdAu, which is 2.18 times of Pt/C (0.221 A mg^?1_Pt) reference. And the current retention rate of PtPdAuNiCo/C (81.3%) is also higher than Pt/C (73.0%) reference in 500-cycle stability test. When as-obtained PtPdAuNiCo/C assembled into a direct ethylene glycol fuel cell, it exhibits a high-power density of 8.38 mW cm^?2. It is 1.40 times than that of Pt/C (6.00 mW cm^?2) reference. This work would be a good reference to HEA materials application on electrocatalysis in future.     

Surface engineering of nanotubular ferric oxyhydroxide “goethite” on platinum anodes for durable formic acid fuel cells

A peerless inexpensive electrochemical engineering of spherical Pt nanoparticles (nano-Pt: ca. 100 nm in average diameter) was achieved with intersected ferric oxyhydroxide nanotubes (α-FeOOH (goethite): ca. 20 nm in average diameter). The FeOOH@Pt catalyst exhibited ca. 2.5 and 1.94-times increases in the catalytic activity and poisoning tolerance, respectively, of the formic acid electro?oxidation (FAO) – the anodic reaction in the direct formic acid fuel cells (DFAFCs). Surprisingly, with a post-activation of the FeOOH@Pt catalyst at 0.48 V vs. reversible hydrogen electrode (RHE) in 0.2 mol L^?1 NaOH, a favorable Fe²⁺/Fe³⁺ transformation succeeded to eliminate the permanent CO poisoning of Pt that impaired the catalytic performance of DFAFCs. This was synchronized (relatively to nano-Pt) with a four-fold increase in the catalytic efficiency, ca. ?174 mV shift in the onset potential, and eightfold enhancement in the catalyst's durability for FAO. The activated FeOOH@Pt catalyst also showed a mass activity of 296 mA mg^?1_Pt (at 0.8 V), which was ca. nine times higher than that (34 mA mg^?1_Pt) of the commercial Pt/C catalyst. The ascertained improvement in the electron transfer at the FeOOH@Pt surface foresees quick industrialization for DFAFCs.     

MoO2 nanocrystals down to 5 nm as Pt electrocatalyst promoter for stable oxygen reduction reaction

The single molybdenum oxide (MoO₂) crystals down to 5 nm in diameter on carbon (denoted as C-MoO₂) are synthesized based on ion-exchange principle for the first time. The structures, morphologies, chemical and electrocatalytic performances of as-synthesized nanomaterials are characterized by physical, chemical and electrochemical methods. The results indicate that electrocatalysts made with Pt nanoparticles supporting on C-MoO₂ (denoted as Pt/C-MoO₂) are highly active and stable for oxygen reduction reaction (ORR) in fuel cells. A mass activity of 187.4 mA mg⁻¹_Pt at 0.9 V is obtained for ORR, which is much higher than that on commercial Pt/C (TKK) electrocatalyst (98.4 mA mg⁻¹_Pt). Furthermore, the electrochemical stability of Pt/C-MoO₂ is more excellent than that of Pt/C (TKK). The origin of the improvement in catalytic activity can be attributed to the synergistic or promotion effect of MoO₂ on Pt. The improvement in electrochemical stability is due to the strong interaction force between Pt and MoO₂.     

Preparation of PEDOT-modified double-layered hollow carbon spheres as Pt catalyst support for methanol oxidation

In this paper, Pt nanoparticles (Pt NPs) deposited hybrid carbon support is prepared by modifying double-layered hollow carbon spheres（DLHCs）with poly(3,4-ethylenedioxythiophene) (PEDOT) and used as anode catalyst of methanol oxidation. The structure of nanocomposites is characterized by SEM, TEM, FT-IR, XRD and XPS, confirming the greatly enhanced synergistic effect between the PEDOT and DLHCs, and illustrating the uniform distribution of Pt NPs on the PEDOT/DLHCs composite surface with a small particle size (~2.63 nm). Cyclic voltammetry, chronoamperometry and impedance spectroscopy applied to determine the electrocatalytic activity of catalysts, it is found that the synthesized PEDOT/DLHCs/Pt possesses excellent characteristics such as large electrochemically active surface area and high mass activity of 59.45 m² g⁻¹ and 807 mA mg⁻¹ in 0.5 M H₂SO₄ containing 1 M methanol solution, which is almost 1.24 and 2.8 times greater than those of commercial Pt/C, and the catalyst exhibits superior stability after 500 durability cycles. The enhanced electrocatalytic behavior can be ascribed to the excellent electronic conductivity of PEDOT-modified DLHCs and the strong binding of PEDOT/DLHCs to Pt NPs, suggesting that the PEDOT/DLHCs/Pt is a promising electrocatalyst for direct methanol fuel cell.     

Feasibility of ultra-low Pt loading electrodes for high temperature proton exchange membrane fuel cells based in phosphoric acid-doped membrane

Factors as the Pt/C ratio of the catalyst, the binder content of the electrode and the catalyst deposition method were studied within the scope of ultra-low Pt loading electrodes for high temperature proton exchange membrane fuel cells (HT-PEMFCs). The Pt/C ratio of the catalyst allowed to tune the thickness of the catalytic layer and so to minimize the detrimental effect of the phosphoric acid flooding. A membrane electrode assembly (MEA) with 0.05 mg_Ptcm⁻² at anode and 0.1 mg_Ptcm⁻² at cathode (0.150 mg_Ptcm⁻² in total) attained a peak power density of 346 mW cm⁻². It was proven that including a binder in the catalytic layer of ultra-low Pt loading electrodes lowers its performance. Electrospraying-based MEAs with ultra-low Pt loaded electrodes (0.1 mg_Ptcm⁻²) rendered the best (peak power density of 400 mW cm⁻²) compared to conventional methods (spraying or ultrasonic spraying) but with the penalty of a low catalyst deposition rate.     

Spatially confined growth of ultrathin NiFe layered double hydroxide nanosheets within carbon nanofibers network for highly efficient water oxidation

The rational design of catalysts with low cost, high efficient and robust stability toward oxygen evolution reaction (OER) is greatly desired but remains a formidable challenge. In this work, a one-pot, spatially confined strategy was reported to fabricate ultrathin NiFe layered double hydroxide (NiFe-LDH) nanosheets interconnected by ultrafine, strong carbon nanofibers (CNFs) network. The as-fabricated NiFe-LDH/CNFs catalyst exhibits enhanced OER catalytic activity in terms of low overpotential of 230 mV to obtain an OER current density of 10 mA cm^?2 and very small Tafel slope of 34 mV dec^?1, outperforming pure NiFe-LDH nanosheets assembly, commercial RuO₂, and most non-noble metal catalysts ever reported. It also delivers an excellent structural and electrocatalytic stability upon the long-term OER operation at a large current of 30 mA cm^?2 for 40 h. Furthermore, the cell assembled by using NiFe-LDH/CNFs and commercial Pt/C as anode (+) and cathode (?) ((+)NiFe-LDH/CNFs||Pt/C(?)) only requires a potential of 1.50 V to deliver the water splitting current of 10 mA cm^?2, 130 mV lower than that of (+)RuO₂||Pt/C(?) couple, demonstrating great potential for applications in cost-efficient water splitting devices.     

Cu-template-dependent synthesis of PtCu nanotubes for oxygen reduction reactions

The development of electrocatalysts with high activity and durability for oxygen reduction reaction (ORR) in acidic electrolyte environments remains a serious challenge for clean and efficient energy conversion. Synergistic effects between Pt and inexpensive metals, the d band center of Pt and catalyst morphology could adjust the adsorption and desorption of oxygen intermediates by the Pt. All the factors affect the catalytic performance of Pt-based nanocrystals. Here, we prepared Cu@PtCu₃ NWs with an average diameter of 74.9 nm for Cu and about 10 nm PtCu₃ layer. After etching, the Cu@PtCu₃ nanowires is transformed into PtCu nanotube structure, due to the removal of copper from the surface and interior. PtCu NTs for ORR shows excellent activities and durability due to the integration of structural advantages and synergistic effects. Notably, the mass activity and specific activity of PtCu NTs (0.105 A mg^?1_Pt and 0.230 mA cm^?2_Pt) are 2.0 and 3.8 times higher than that of commercial Pt/C (0.053 A mg^?1_Pt and 0.06 mA cm^?2_Pt). The etching process to change the morphology of the catalyst and alter the electronic structure of the catalyst is expected to be useful for the design of future structured Pt-based alloy nanocatalysts.     

ZrO2 anchored core-shell Pt–Co alloy particles through direct pyrolysis of mixed Pt–Co–Zr salts for improving activity and durability in proton exchange membrane fuel cells

Highly active and durable Pt-based catalysts for oxygen reduction reaction (ORR) are very important and necessary for the proton exchange membrane fuel cells (PEMFCs). In this paper, we report the preparation and performance study of ORR catalysts composed of core-shell Pt–Co alloy nanoparticles (NPs) on multi-walled carbon nanotubes (MWCNTs) anchored with ZrO₂ NPs (denoted as Pt–Co–ZrO₂/MWCNTs). Thanks to the unique three-phase structure, the mass activity of Pt–Co–ZrO₂/MWCNTs for ORR at 0.9 V versus reversible hydrogen electrode (RHE) is1577 mA mg_Pt^?1, which is ～6.6-fold higher than that of the commercial Pt/C (238 mA mg_Pt^?1). After 50,000 cycles for durability test, the mass activity of Pt–Co–ZrO₂/MWCNTs for ORR remained 88% of its initial value. In stark contrast, that of Pt/C kept only about 56.3% of its initial value. More importantly, its catalytic performance was fully observed/verified in a H₂-air PEMFC single cell test. When the Pt loading of Pt–Co–ZrO₂/MWCNTs loaded cathode was one fourth of that with commercial Pt/C as the cathode catalyst, comparable cell performance was achieved. More impressively, the MEA with Pt–Co–ZrO₂/MWCNTs underwent only 24.5% degradation in maximum power density after 30,000 accelerated durability tests (ADTs). However, the MEA with Pt/C after 30,000 ADTs exhibited 39.6% performance loss in maximum power density. The enhanced mass activity and catalytic durability of Pt–Co–ZrO₂/MWCNTs could be attributed to the core-shell Pt–Co alloy NPs with Pt-rich surface and the interface effect between Pt–Co alloy NPs and oxygen vacancy-rich ZrO₂ NPs. In addition, this research also provided a solution to the durability issue of cathodes without sacrificing ORR mass activity, which would promote practical application of PEMFCs.     

Boosting alcohol electro-oxidation reaction with bimetallic PtRu nanoalloys supported on robust Ti0.7W0.3O2 nanomaterial in direct liquid fuel cells

In this work, an anatase Ti_0.7W_0.3O₂-supported Pt₃Ru nanoparticles (NPs) were fabricated by combining the advantages of the non-carbon Ti_0.7W_0.3O₂ nanosupport and the synergistic effect of the bimetallic Pt₃Ru nanoalloy that was investigated as electrocatalyst toward alcohol electrochemical oxidation. The bimetallic Pt₃Ru nanoparticles with ~3 nm in diameter were relatively well-dispersed on the surface of the anatase Ti_0.7W_0.3O₂ nanosupport via a surfactant-free microwave-assisted polyol route that, which was attributable to the good dispersibility of ethylene glycol and the rapid, uniformity of the microwave heating. For methanol and ethanol electrochemical oxidation, the as-obtained Pt₃Ru (NPs)/Ti_0.7W_0.3O₂ electrocatalyst exhibited the low onset potential (~0.10 V vs. NHE for MOR and ~0.35 V vs. NHE for EOR) and high mass activity (~350.84 mA mg_Pt^?1 for MOR and ~274.59 mA mg_Pt^?1 for EOR) compared to the commercial Pt (NPs)/C (E-TEK) electrocatalyst. Additionally, the CO-stripping and CA results indicated the remarkably enhanced CO-tolerance of the Pt₃Ru (NPs)/Ti_0.7W_0.3O₂ catalyst. After the 5000-cycle accelerated durability test (ADT) in acidic ethanol media, the bimetallic Pt₃Ru (NPs)/Ti_0.7W_0.3O₂ catalyst only showed the mass activity loss of 19.11% of its initial mass activity, compared with the severe deterioration of 44.04% of the commercial Pt (NPs)/C (E-TEK) catalyst. The outstanding results could be interpreted due to the bifunctional mechanism of the Pt₃Ru nanoalloys combining with the synergistic effect between the bimetallic nanoalloy and the mesoporous Ti_0.7W_0.3O₂ nanosupport as well as the superior anti-corrosion of the TiO₂-based nanosupport under acidic and oxidative environments.     

Pt nanowire growth induced by Pt nanoparticles in application of the cathodes for Polymer Electrolyte Membrane Fuel Cells (PEMFCs)

Improving cathode performance at a lower Pt loading is critical in commercial PEMFC applications. A novel Pt nanowire (Pt-NW) cathode was developed by in-situ growth of Pt nanowires in carbon matrix consisting Pt nanoparticles (Pt-NPs). Characterization of TEM and XRD shows that the pre-existing Pt-NPs from Pt/C affect Pt-NW morphology and crystallinity and Pt profile crossing the matrix thickness. The cathode with Pt-NP loading of 0.005 mg_Pt-NP cm^?2 and total cathode Pt loading of 0.205 mg_Pt cm^?2 has the specific current density of 89.56 A g_Pt^?1 at 0.9 V, which is about 110% higher than that of 42.58 A g_Pt^?1 of the commercial gas diffusion layer (GDE) with Pt loading of 0.40 mg cm^?2. When cell voltage is below 0.48 V, the Pt-NW cathode has better performance than the commercial GDE. It is believed that the excellent performance of the Pt-NW cathode is attributed to Pt-NP induction, therefore producing unique Pt-NW structure and efficient Pt utilization. A Pt-NW growth mechanism was proposed that Pt precursor diffuses into the matrix consisting of pre-existent Pt-NPs by concentration driving, and Pt-NPs provide priority sites for platinum depositing at early stage and facilitate Pt-NW growth.     

Highly efficient PtCo nanoparticles on Co–N–C nanorods with hierarchical pore structure for oxygen reduction reaction

Developing platinum-based nanoparticles on carbon catalysts with high activity and stability for oxygen reduction reaction (ORR) is of great significance for the practical application of fuel cells. Herein, a synchronous strategy of preparing nano-sized PtCo supported on atomic Co and N co-doped carbon nanorods (PtCo/Co–N–C NR) was developed to replace the conventional method of impregnating Pt sources into ready-made carbon materials, in which metal-organic frameworks (MOFs) with Co and Zn ions of rhombic dodecahedron were first prepared using 2-methylimidazole as building block and then their morphology was transformed into porous nanorods via the reduction of Co ions to Co–B–O complex in the MOFs by NaBH₄; subsequently, Pt was deposited on the Co–Zn MOF nanorods through the displacement reaction of PtCl₆^2- and metallic Co and coordination between MOF and PtCl₆^2-; after pyrolysis and acid-leaching process, highly dispersed PtCo/Co–N–C NR was obtained. Attributed to its unique characteristics of hierarchical pore structure, uniform PtCo alloy nanoparticles with the average size of 7.0 nm and strong supporting interaction effect, the catalyst exhibits high ORR activity and stability with the mass activity of 577.0 mA mg^?1_Pt and specific activity of 1.4 mA cm^?2 at 0.9 V vs RHE in 0.1 M HClO₄, which is about 3.6 times and 3.5 times high than that of commercial Pt/C catalyst respectively. This strategy would provide a flexible route to develop highly active and stable ORR electrocatalysts with various morphologies for optimizing the exposure of active sites.