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Due to the inherent sluggish kinetics of oxygen evolution reaction (OER), designing high-efficient and stable electrocatalysts is essential and urgent for the practical use of energy conversion devices. The transition-metal based layered double hydroxide (LDH) is considered as an alternative candidate with desired OER activity, while its catalytic performance is impeded by the limited active sites, poor conductivity and durability. Herein, the ultrafine and well-dispersed Ru nanoparticles doped NiFe LDH (Ru-NiFe-LDH) is designed as highly efficient electrocatalyst for OER. Benefiting from synergistic electronic modulation, as well as the abundant active interfaces, between Ru nanoparticles and NiFe LDH, Ru-NiFe-LDH shows superior electrocatalytic activity in alkaline electrolyte with a low overpotential of 256 mV at the current density of 50 mA cm−2. Moreover, the Ru-NiFe-LDH exhibits comparable activity toward oxygen reduction (ORR). As a concept verification, a homemade Zn-air battery assembled by Ru-NiFe LDH presents desired performance and stability under practical operating conditions. This work may broaden the family of advanced electrocatalysts for electrochemical energy conversion. The abundant active interfaces were constructed in ultrafine Ru nanoparticles doped NiFe LDH to promote electrocatalytic oxygen evolution in alkaline condition. [Display omitted] [ABSTRACT FROM AUTHOR]

Exploring metal-free, highly active and durable electrocatalysts with tunable selectivity toward oxygen reduction reaction (ORR) still remains a standing challenge. Herein, porous carbon nanotubes derived from a self-supporting hyper-cross-linked polymer with tailored selectivity for efficient ORR are reported. The sulfur-containing tubular polymer provides a versatile platform to fabricate diverse heteroatom doped porous carbon nanotubes. Attributed to the porous tubular morphology, abundant dopants and defects, the N-doped porous carbon nanotubes through pyrolysis under Ar-NH 3 show excellent 4e− ORR performance with a half-wave potential (E 1/2) of 0.85 V. It also has superior stability and methanol tolerance. Meanwhile, the O, S co-doped porous carbon nanotubes through oxygen plasma treatment show enhanced 2e− ORR performance with a selectivity up to 85.4%, which is probably ascribed to the more C=O and COOH species introduced in the carbon matrix. This work not only provides a useful strategy to design and prepare efficient ORR catalysts, but also paves the avenue for the facile tailoring of selectivity in ORR process. Diverse porous carbon nanotubes derived from a self-supporting hyper-cross-linked polymer with tailored selectivity for efficient electrocatalytic oxygen reduction reaction is reported. [Display omitted] [ABSTRACT FROM AUTHOR]

Palladium-based catalyst represents one of the most promising candidates among all non-platinum oxygen reduction reaction (ORR) catalysts. However, it is still challenging to precisely engineering their morphology and composition. Herein, highly branched core-shell PdCu@Pd nanocrystals have been fabricated via a simple one-pot synthesis that co-directed by hydrogen gas and halide ions. Such unique PdCu@Pd nanocrystals exhibit prominent ORR activity, durability and methanol-tolerance in alkaline media owing to their core-shell composition, highly-branched structure and defect-rich surface. This work elucidates a facile strategy to design highly branched core-shell nanomaterials, shedding light on the exploration and optimization of novel non-platinum ORR catalysts. A facile method for one-pot synthesis of Defect-rich PdCu@Pd Core-shell Nanobranches is developed. The as-made catalyst shows superior activity, durability and methanol-tolerance towards oxygen reduction reaction. Image 1 [ABSTRACT FROM AUTHOR]