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[Display omitted] • Highly porous carbon network was derived from zeolitic-imidazole frameworks. • Co-deposition on porous carbon enhanced the catalytic activity. • Co on carbon was electrochemically stable as cathode material during 520 h cycling. Porous carbon wrapped on cobalt catalyst is one of the promising candidates to replace noble metal-based catalysts for ORR. Herein, a porous carbon network (PCN) was obtained by synthesis of zeolitic-imidazole frameworks (ZIF-8) followed by pyrolysis at 1050 ℃ under a nitrogenous atmosphere and the cobalt (Co) was deposited on PCN to obtain Co-PCN by sequential reduction method. The PCN showed a relatively high specific surface area of 806.43 m2/g and decreases to 329.4 m2/g with the introduction of Co contents in PCN. The Co-PCN reveals excellent performance having a current density of 350 mA cm−2 for the ORR at 0.5 V after 20th cycles as a cathode material in rechargeable zinc-air batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fabrication of nickel-cobalt nanocage for oxygen evolution reactions. • Excellent oxygen evolution reaction performance with overpotential of 350 mV. • Synergic effect of cobalt-nickel catalyst improves the conductivity and charge transfer. The development of efficient, eco-friendly, and inexpensive electrocatalysts has become crucial and significant in water-splitting applications. Herein, we developed a nickel-cobalt nanocage (Ni/Co-NC) electrocatalyst via the solvothermal method which can boost the performances towards oxygen evolution reactions (OER) and hydrogen evolution reactions (HER). The Ni/Co-NC reveals significant performance at an onset potential of 350 mV for the OER at a delivered current density of 10 mA cm−2. The significant amount of oxygen vacancies generated by the addition of nickel in cobalt has been verified by XPS and the nanocage structure revealed by TEM and SEM images helps in effective performance for OER/HER. Furthermore, the synergistic effect between various Ni3+/Ni2+ and Co2+ could optimize the performance resulting in a smaller Tafel slope of 70 mV dec−1 for Ni/Co-NC. [ABSTRACT FROM AUTHOR]

[Display omitted] • Polyvinyl alcohol (PVA) based nanofibers were prepared via centrifugal spinning. • Scanning electron microscopy images reveled the diameter of nanofibers. • PVA based nanofibers were antibacterial against S. aureus and E. coli. In this study, three types of nanofibers, i.e. polyvinyl alcohol (PVA), alginate di-aldehyde (ADA)/PVA, and ADA-gelatin (GEL)/PVA, were fabricated via centrifugal spinning. The spinability of ADA was improved by mixing with PVA. Furthermore, GEL and sesame oil were added in the ADA solution to control the degradation kinetics and to improve the viscosity of the solution, respectively. Later, the solution was fed to a rotating spinneret (3000 rpm at 250 °C) which led to the fabrication of nanofibers. The developed nanofibers were loaded with copper-silver (Cu-Ag) doped mesoporous bioactive glass nanoparticles (MBGNs) to provide therapeutic effects (antibacterial effect). Scanning electron microscopy images showed that the nanofiber diameters were 139 ± 62 nm, 258 ± 42 nm, and 281 ± 34 nm, for PVA, ADA/PVA, and ADA-GEL/PVA respectively, with web-like morphology. Fourier transform infrared spectroscopy confirmed the presence of chemical bonds attributed to the ADA, GEL, and PVA components. The results of the inhibition halo test confirmed that the nanofibers (ADA-GEL/PVA & ADA/PVA) exhibit potent antibacterial effect against Staphylococcus aureus and Escherichia coli. [ABSTRACT FROM AUTHOR]

• Fabrication of efficient bimetallic catalysts for OER. • Nickel decoration was performed on bimetallic CNT/CoNi. • Ni/CNT/CoNi exhibited excellent electrochemical performance and cycling stability. The fabrication of efficient catalysts for the oxygen evolution reactions (OER) that are required to accelerate the sluggish kinetics of metal-air batteries has attracted significant attention for application in energy conversion devices. Metal-organic frameworks (MOFs) have been recognized as potential candidates for the formation of promising catalysts. In this study, we report the formation of Ni/CNT/CoNi using bimetallic-ZIF (CoNi-ZIF) as a precursor. Bimetallic CoNi encapsulated in carbon nanotubes (CNTs) was obtained by calcinating CoNi-ZIF-67 to yield CNT/CoNi. The resulting CNT/CoNi was highly porous with a significant specific surface area of 242 m2/g. After calcination, Ni deposition on the CNT was performed and the surface area was reduced to 168.7 m2/g. Ni/CNT/CoNi was applied as a cathode material in zinc-air batteries, exhibiting excellent electrochemical performance and cycling stability. [ABSTRACT FROM AUTHOR]

• Nickel deposited catalysts using Zeolitic-Imidazolate Frameworks-67 as a precursor were synthesized. • The catalysts exhibited higher catalytic activities for oxygen reduction and evolution reactions. • The catalysts show low overpotential and high stability. Zeolitic imidazolate framework containing cobalt and nickel (Co- and Ni-ZIF-67) were used as a precursor to perform Ni deposition, in order to obtain enhanced catalytic activity and nanocatalysts. Co or Ni embedded in the carbon nanotubes (CNTs) were obtained by the heat treatment of Co- or Ni-ZIF-67. On Co or Ni embedded CNTs, Ni-deposition was performed to obtain the Ni-deposited catalysts, Ni-CNT-(Co or Ni), which have a higher surface area of 136.7 and 259 m2/g, respectively. These catalysts exhibit superior performance, low overpotential, and high stability for both oxygen reduction and evolution reactions. The superior performance is attributed to metal deposition, which creates highly active catalytic sites and has potential application as a catalyst for the rechargeable zinc-air battery. [ABSTRACT FROM AUTHOR]