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In order to facilitate widespread commercialization of proton‐exchange membrane fuel cells (PEMFCs), the synthesis of advanced catalysts toward oxygen reduction reaction with high activity and stability is essential. Here, we report the synthesis of strongly coupled porous Pt nanospheres /three‐dimensional graphene (P−Pt @3DG) hybrid materials through a facile strategy. The P−Pt @3DG displays an excellent oxygen reduction reaction (ORR) performance with the mass activity of 0.542 A/mgPt and specific activity of 0.976 mA/cm2 at 0.9 V vs. RHE, respectively, which are 4.0‐ and 3.7‐ times higher than those of commercial Pt/C catalysts. More importantly, high stability with only 5.35 % loss after 10,000 cycles is achieved. The superior performance of P−Pt @3DG is mainly attributed to the open structure of porous Pt spheres, which exposes the internal Pt atoms with an ultrahigh Pt utilization. Moreover, the 3D graphenes possess an open and interconnected porous structure and allow efficient charge and mass transfer. Besides, this synthetic method is suitable for large scale production, which is highly applicable to the commercialization of PEMFCs. [ABSTRACT FROM AUTHOR]

[Display omitted] Platinum-based alloy nanowire catalysts demonstrates great promise as electrocatalysts to facilitate the cathodic oxygen reduction reaction (ORR) of proton exchange membrane fuel cells (PEMFCs). However, it is still challenge to further improve the Pt atom utilization of Pt based nanowires featuring inherent structural stability. Herein, a new structure of PtCo nanowire with nanodendrites was developed using CO-assistance solvent thermal method. The dendrite structure with an average length of about 7 nm are characterized by a Pt-rich surface and the high-index facets of {5 3 3}, {3 3 1} and {3 1 1}, and grows from the ultra-fine wire structure with an average diameter of about 3 nm. PtCo nanowires with nanodendrites developed in this work shows outstanding performance for ORR, in which its mass activity of 1.036 A/mg Pt is 5.76 times, 1.74 times higher than that of commercial Pt/C (0.180 A/mg Pt) and PtCo nanowires without nanodendrites (0.595 A/mg Pt), and its mass activity loss is only 18% under the accelerated durability tests (ADTs) for 5k cycles. The significant improvement is attributed to high exposure of active sites induced by the dendrite structure with Pt-rich surface with the high-index facets and Pt-rich surface. This structure may provide a new idea for developing novel 1D Pt based electrocatalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • We synthesized Au@PtNiAu concave octahedral core-shell nanocatalysts (Au@PtNiAu-COCS). • The mass activity of this catalyst is 11.22 times in ORR and 4.56 times in MOR than commercial Pt/C. • It exhibits a superior power density under fuel cell operation and better performance. • Its half-wave potential displacement after 30 k cycles is only 12 mV. • It retained the 78.8% of MA after 30 k cycles in ORR and lower CO oxidation overpotential in MOR. Despite the remarkable research efforts, the lack of ideal activity and state-of-the-art electrocatalysts remains a substantial challenge for the global application of fuel cell technology. Herein, is reported the synthesis of Au@PtNiAu concave octahedral core-shell nanocatalysts (Au@PtNiAu-COCS) via solvothermal synthesis modification and optimization approach. The special structure generating a large number of step atoms, enhancing the oxygen reduction reaction (ORR) and methanol oxidation reaction (MOR) activity and stability. The superior ORR mass activity of the Au@PtNiAu-COCS is 11.22 times than the exhibited of Pt/C initially by Pt loading, and 5.11 times by Pt + Au loading. After 30 k cycles the mass activity remains 78.8% (8.83 times the initial Pt/C activity) and the half-wave potential only shifts 12 mV. Au@PtNiAu-COCS has superior half-cell activity and gives ideal membrane electrode assemblies. Furthermore, for MOR the Au@PtNiAu-COCS show enhanced anti-toxic (tolerant) ability in CO. This work provides a new strategy to develop core-shell structure nanomaterials for electrocatalysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mn-N-C catalysts were developed by a newly designed bis(imino)-pyridine precursor. • The structures of Mn-N-C are dependent on the growth of the precursor with NaCl. • The Mn-N-C nanosheets with short Mn-N length shows excellent ORR performance. • This work provides new understanding for the rational design of M−N−C. Revealing the correlation between the micro–macro structures and active sites of transition metal-nitrogen-carbon (M−N−C) for electrochemical oxygen reduction reaction (ORR) is essential to develop non-precious metal catalyzed fuel cells and metal-air batteries. Herein, Mn-N-C catalysts with various morphologies and microstructures were prepared using Mn2+ coordinated bis(imino)-pyridine-based polymer with N-rich content as a new platform of precursor, which was synthesized via a condensation reaction of 1H-1, 2, 4-Triazole-3, 5-Diamine and 2, 6-Diacetylpyridine. Results demonstrate that morphologies and fine structures (pore structure, N dopants, surface area, and atomic Mn-N bond length, etc.) of Mn-N-C catalysts are strongly dependent on the growth of the specific precursor with and without NaCl as a template and the secondary calcination temperature can further optimize the bond length of Mn-Nx moieties, resulting in significant activity differences between correspondingly derived Mn-N-C catalysts for ORR. Compared to Mn-N-C derived from the synthesized precursor without NaCl, Mn-N-C obtained by the precursor grown directly on NaCl features an ultra-thin nanosheet-like structure with a hierarchical pore distribution and a shorter Mn-N bond, presenting high ORR performance with a half-wave potential of 0.88 V in 0.1 M KOH and a tiny potential loss of 11 mV after 30 K cycles, which is also proved by high-performance practical single Zn-Air battery (139 mW·cm−2) and proton exchange membrane fuel cell (400 mW·cm−2). This work provides a new understanding of the critical role of morphology and Mn-N bonding length of M−N−C for enhancing ORR and a new route of developing non-Fe/Co-based M−N−C catalysts for electrocatalysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • A synchronous complexation-polymerization strategy of synthesizing M−N−C electrocatalysts was developed. • As-synthesized Fe-N-C exhibits excellent ORR performance in Zn-air battery and fuel cell. • This strategy provides a flexible platform to advance molecular-level design and synthesis M−N−C catalysts. Developing atomic transition metal coordinated by nitrogen doped carbon (M−N−C) eletrocatalysts for oxygen reduction reaction (ORR) is critical to achieve low cost metal-air batteries and fuel cells. Herein, a general method of synthesizing M−N−C was developed via a synchronous complexation-polymerization strategy, in which nitrogen-containing ligand was coordinated with specific transition metal ions and diamino aromatic compound was simultaneously polymerized by the metal ion as initiator; by the following pyrolysis in a molten NaCl bath, M−N−C was finally synthesized. Fe-N-C was synthesized by this strategy using 2, 4, 6-Tri (2-pyridyl)-1, 3, 5-triazine (TPTZ) as ligand for FeCl 2 , and 1, 8-Diaminonaphthalene (DAN) as monomer of polymerization. Results demonstrate that introducing DAN into TPTZ-Fe2+ significantly affect the derived carbon structure and electrochemical performance of corresponding Fe-N-C. The Fe-N-C prepared by TPTZ and DAN with the molar ratio of 1:1 shows excellent ORR activity and durability, whose initial half-wave potential is 0.90 V in 0.1 M KOH and 0.80 V in 0.5 M H 2 SO 4 respectively, after 10 K cycles, the potential is only 14 mV loss in 0.1 M KOH and 20 mV decay in 0.5 M H 2 SO 4. And the ORR performance as cathode is further proved by a single practical Zn-air battery with a maximum power density of 192 mW cm−2 and a specific capacity of 800 mAh g Zn -1, much higher than 137 mW cm−2 and 735 mAh g Zn -1 of the same loading of commercial Pt/C catalyst and proton exchange membrane fuel cell with a high power output of 640 mW cm−2. Attributed to the vast kinds of ligands, metal ions and polymerizing monomers, this strategy provides a flexible platform of synthesizing advanced M−N−C catalysts, compared with other reported methods. [ABSTRACT FROM AUTHOR]

• Newly quaternary PtCoNiMo hexapod nano-skeletons (NSs) with a novel structure, were synthesized. • Vertex-reinforced PtCoNiMo hexapod NSs possess abundant tip areas with high-index faces. • Mo-modified quaternary hexapod NSs composed of core, first- and second-layer feet show better properties. • PtCoNiMo NSs show enhanced mass activity, stability and anti-poisoning ability than commercial Pt/C. • Vertex-reinforced PtCoNiMo hexapod NSs facilitates electron transfer and mass exchange. Noble metal binary and ternary catalysts have become a new class of fuel cell electrocatalysts due to their high catalytic activity. However, improvement is still necessary to reduce the consumption of Pt and obtain the quaternary Pt-based catalyst by Mo modification. Through the introduction of Mo(CO) 6 , novel quaternary hexapod nano-skeletons with high-index facets are obtained here, which are composed of core, first-layer feet and second-layer feet. Compared with PtCoNi nano-particles (NPs), the vertex-reinforced PtCoNiMo hexapod nano-skeletons (NSs), due to abundant tip areas, can facilitate electron transfer and mass exchange. It is found that the as prepared PtCoNiMo nano-skeletons catalyst exhibits enhanced mass activity, stability and anti-poisoning ability towards methanol oxidation reaction and oxygen reduction reaction, compared to commercial Pt/C catalyst and PtCoNi nanoparticles. More importantly, the development of quaternary catalysts can create better possibilities for the performance improvement of Pt-based catalysts. [ABSTRACT FROM AUTHOR]