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Incorporating metal compound nanoparticles in carbonaceous matrix is a valid strategy to fabricate highly efficient oxygen reduction electrocatalysts. Herein, N, P-codoped carbon nanotubes embedded with Fe2P nanoparticles (Fe2P/NPCt) were synthesized in this work. Results show carbon nanotubes have a large specific surface area (987 m² g−1 ) with an inner diameter of ∼60 nm. About 5.90 wt% nitrogen (35.18% pyridinic N) and 2.56 wt% phosphorus (mainly in the form of P–C and P–Fe) was doped in Fe2P/NPCt. HRTEM and XRD results confirmed the well dispersed Fe2P nanoparticles in 5 ∼10 nm on carbon nanotubes. The electrochemical performance of Fe2P/NPCt was evaluated in 0.10 M KOH using cyclic voltammetry, linear scanning voltammetry, and chronoamperometry. Fe2P/NPCt exhibits high electrocatalytic activity towards oxygen reduction with an onset potential of 1.029 V (vs RHE) and a limited current density of 6.79 mA cm−2, surpassing those of 20% Pt/C (0.950 V and 5.20 mA cm−2 ). Furthermore, Fe2P/NPCt presents outstanding durability and good methanol tolerance during long-term ORR. When assembled in a primary zinc-air battery (ZAB), the maximum power density and specific capacity of ZAB reach 175.48 mW cm−2 and 744.1 mAh g−1, respectively, outperforming ZAB equipped with 20% Pt/C. [ABSTRACT FROM AUTHOR]

Transition metal/nitrogen carbon composite (M/NC) is a highly active oxygen reduction reaction (ORR) electrocatalyst, widely used in fuel cells and zinc-air batteries. Herein, a uniform and regular PVP-assisted iron-doped nano dodecahedron (ZP0.1F/NC) is prepared by a simple and efficient one-step in-solution reaction, followed by controlled in situ pyrolysis. The synthesized electrocatalyst showed excellent electrocatalytic ORR activity in an alkaline medium. Compared with standard 20% Pt/C electrocatalyst, ZP0.1F/NC exhibited onset potential (Eonset) (0.974 V vs 0.967 V), half-wave potential (E1/2) (0.861 V vs 0.857 V) and the limiting current density (jd) was 6.373 mA cm−2 vs 5.401 mA cm−2, also better than the Fe doped ZIF-8 nitrogen composite (ZF/NC), PVP auxiliary ZIF-8 (ZP0.1/NC) and pure ZIF-8 nitrogen composite (Z/NC) synthesized by the same procedure. In addition, the zinc-air battery assembled with ZP0.1F/NC also exhibits outstanding discharge capacity, with a specific capacity and energy density of 793.3 mAh g−1 and 974.9 Wh kgZn-1 respectively, much higher than that of commercial 20% Pt/C based zinc-air battery (719.8 mAh g−1, 842.6 Wh kgZn-1 ), indicating its great potential in practical energy conversion and storage. [ABSTRACT FROM AUTHOR]