Rationally Designed Co₃O₄–C Nanowire Arrays on Ni Foam Derived From Metal Organic Framework as Reversible Oxygen Evolution Electrodes with Enhanced Performance for Zn–Air Batteries

Abstract

The development of high activity and stability nonprecious metal catalysts for oxygen evolution and reduction is necessary to solve energy supply issues. Here, porous nanowire arrays composed of Co 3 O 4 nanoparticles and carbon species are prepared by a facile carbonization of the metal−organic framework materials of ZIF-67 which directly grow on Ni foam. The obtained hybrid materials possess a large surface area of 345 m 2 g −1 and a high carbon content. The hierarchically interconnected nanowire arrays with porous structure strongly immobilized on Ni foam facilitate the diffusion of generated gas, shorten electrolyte diffusion distance, and enhance charge transport. As the working electrode for oxygen evolution reaction without any extra modification in 1.0 M KOH, it can provide a stable current density of 10 mA cm −2 at 1.54 V (vs RHE), along with robust durability. Additionally, the Co 3 O 4 −C hybrid materials worked as oxygen reduction catalyst exhibit a positive onset potential of 0.91 V, large limiting current density, and excellent stability. When used as the air catalysts for primary Zn−air batteries, the assembled batteries deliver a large peak power density of 118 mW cm −2 and excellent operation stability. A variety of characterization results and controlled experiments demonstrate that the efficient performance of this hybrid material toward electrocatalytic reactions originates from the unique electrode configuration, intimate distribution of active species, hierarchically porous configuration, high conductivity of Ni foam, and synergistic effect of Co 3 O 4 and carbonaceous materials.

Facile synthesis of molybdenum carbide nanoparticles in situ decorated on nitrogen-doped porous carbons for hydrogen evolution reaction

“…The commercial Pt/C exhibits a low onset potential ( E onset ) nearly zero, revealing the favorable hydrogen evolution capability. The fabricated Mo 2 C/NC possesses an onset potential at about −200 mV, evidently lower than that of other prepared electrocatalysts, especially Mo 2 C and Mo 2 N, indicating the importance of carbonaceous materials in hybrids for electrocatalytic process [18,23,42] . The overpotential at the current density of 10 mA cm −2 ( J 10 ) is a vital indicator to evaluate the catalytic capability of electrocatalysts towards HER.…”

Recent Advances in Metal‐Organic Framework Derivatives as Oxygen Catalysts for Zinc‐Air Batteries

“…In this regard, hollow and core/shell structures,,,, 1D thin rods/bars,,,,,,,,,, 2D thin sheets,,,,,,, are shown to be favorable. In addition, highly interconnected 3D structures,,,, are also beneficial to improving the long‐range electronic conductivity of the cathode.…”

“…Besides the above‐mentioned ZnO‐assisted synthesis,,,, hard‐templated synthesis with other templates such as SiO 2 , MnO 2 and metal Te have also been reported. In addition, other methods like hydrothermal and electrospinning, have also been developed to synthesize MOFs with special morphologies. The resulting catalysts demonstrated a significant improvement in the performance of Zn–air batteries.…”

Hierarchically Porous Heteroatoms‐doped Vesica‐like Carbons as Highly Efficient Bifunctional Electrocatalysts for Zn‐air Batteries

“…The electrocatalytic bifunctionality of oxygen cycle is of vital issue for rechargeable metal‐air battery, wherein the ORR and OER processes happen on the air cathode during the discharging and charging stages. As displayed in Figure a, polarization curves were collected in the region of OER and ORR to verify the reversible catalytic ability of the fabricated catalysts towards oxygen electrocatalytic reactions . In the OER region, commercially received IrO 2 reveals a more negative onset potential ( E onset ) of 1.45 V, along with drastically increased anodic current.…”

“…Currently the oxygen electrochemistry, referring to oxygen reduction/evolution reactions (ORR/OER), has been considered as the critical step for the development of some energy storage and conversion systems, such as, rechargeable metal‐air batteries and regenerative fuel cells . Nevertheless, noble metal materials, for instance, Pt and its alloys for ORR and IrO 2 /RuO 2 for OER, remain the efficient electrocatalysts to decrease the large overpotentials resulted from polarization effect and unfavorably sluggish kinetics caused by multi‐electron process . To overcome the unfavorable cost and accelerate the practical applications, an appropriate specific amount of efficient non‐precious transition metal compound materials including oxides, hydroxides, sulfides, phosphides, and phosphates, have been well‐developed for electrochemical oxygen reduction and evolution reactions, exhibiting considerable electrocatalytic performance .…”