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• Long-range interconnected nanoporous Co/Ni/C composites for bifunctional oxygen electrocatalyst. • Co/Ni/C composites formed via etching the pyrolyzed CoNi-MOFs. • Co/Ni/C composites exhibited a comparable ORR/OER stability over 130 h/10 h. • Co/Ni/C composites exhibited long-life rechargeable zinc-air batteries exceeding 620 h at 5 mA cm−2 and 430 h at 10 mA cm−2. Zinc–air batteries are considered to be a promising candidate for use as a sustainable power source, due to their higher energy density and more economical features. However, it is necessary to design efficient and durable electrocatalysts, especially the durability, for bifunctional oxygen reduction (ORR) and oxygen evolution reactions (OER). Therefore, it is imperative to developing reliable zinc-air batteries with long-lasting cycle lifetime. Herein, we report long-range interconnected nanoporous Co/Ni/C composites in µm-length scale as highly active and stable bifunctional electrocatalysts for long-life rechargeable zinc-air batteries. The composite catalysts consist of N and S co-doped hollow carbon and carbon-encapsulated CoNi alloy nanoparticles, which serve as catalytically active sites for the ORR/OER. Meanwhile, the long-range interconnected nanoporous carbon structure in µm-length scale favors fast ion and electron transfer during the reactions, and can prevent the catalyst deterioration against nanoparticles collapse and agglomerate into large ones during the long-term battery operation. As a result, compared to the commercial precious metal-based catalysts, the Co/Ni/C composite catalysts exhibit a significantly improved stability towards the ORR/OER with small activity decay after 100 h/10 h of operation under chronoamperometric polarization. Especially, the resulting zinc-air battery demonstrates remarkable cycling stability exceeding 620 h and 430 h at 5 and 10 mA cm−2, respective. [Display omitted]. [ABSTRACT FROM AUTHOR]

The development of electrocatalyst possessing superior oxygen reduction reaction (ORR) activity is highly desirable due to the low sluggish kinetics at the cathode of fuel cell. Here, CoFe 2 O 4 nanoparticles embedded in N-doped carbon nanotubes electrocatalyst (denoted as CoFe 2 O 4 -NC) is synthesized via polymerization of pyrrole, absorbing metal ion and annealing under Ar/NH 3 atmosphere. By in situ integrating the catalytically active CoFe 2 O 4 nanoparticles with the N-doped carbon nanotubes and enhancing electrical conductivity, the as-obtained electrocatalyst exhibits excellent ORR activity and long-term stability with a half-wave potential of 0.86 V and 10 h continuous cycling, outperforming the reported similar catalysts. This work opens a new path for the expansion of low cost and efficient ORR electrocatalysts to substitute Pt-based metals for energy storage and conversion devices. [Display omitted] • In situ synthesis of CoFe 2 O 4 nanoparticles embedded in N-doped carbon nanotubes. • CoFe 2 O 4 -NC exhibits excellent ORR activity with a half-wave potential of 0.86 V and long-term stability. • The immobilization of particles on carbon tube prevents the CoFe 2 O 4 nanoparticles from dissolving or aggregating. [ABSTRACT FROM AUTHOR]

The advancement of highly-efficient, non-noble metal electrocatalysts with high active sites for oxygen evolution reaction (OER) continues to face severe challenges. In this work, a new 3D flower-like α-Co(OH) 2 catalyst with high Co–NH 2 active sites (referred to as α-Co(OH) 2 –NH 2) is prepared. The Co–NH 2 active sites are formed through the interactions between Co2+ and –NH 2 groups and exhibit higher electrocatalytic performance for OER in alkaline mediums, with a lower overpotential (300 mV at 10 mA cm−2), a flatter Tafel slope (75 mV dec−1) and a longer stability. Moreover, water splitting catalyzed by α-Co(OH) 2 –NH 2 delivers 1.62 V to reach a current density of 10 mA cm−2. The mechanism studies show that the OER electrocatalytic activity is closely related to the content of –NH 2. Density functional theory (DFT) calculations unveil that –NH 2 groups can facilitate the formation of OH∗ on the α-Co(OH) 2 surface and promote the desorption of O 2 ∗ into O 2(g). • A new type Co–NH 2 active sites in OER electrocatalyst was obtained by in-situ coordination strategy. • The electrocatalyst shows excellent OER activity and stability. • The OER electrocatalytic activity can be tuned by –NH 2 content. • Water splitting catalyzed by α-Co(OH) 2 –NH 2 delivers 1.62 V to reach a current density of 10 mA cm−2. [ABSTRACT FROM AUTHOR]

Air pollutants are important factors that contribute to the development and exacerbation of asthma, but experimental evidence still needs to be collected and the mechanisms still need to be addressed. In this study, we aimed to assess the association between PM2.5 exposure and asthma development. The effects of PM2.5 exposure on the barrier functions of airway epithelial cells were also determined. PM2.5 was collected from Nanjing, China, and its soluble extract was prepared. Human lung epithelial cells (BEAS-2B) were treated with different concentrations of soluble PM2.5 extract, and cell viability was detected by FACS using Annexin V-FITC staining. PM2.5-induced oxidative stress and inflammatory events were assessed by DCF-DA staining and qPCR. PM2.5-induced dysfunction of the airway epithelial barrier was assessed by measuring the expression of tight junction molecules. In vivo, BALB/c mice were treated with OVA in the presence or absence of PM2.5 solution, followed by exposure to OVA aerosols. Allergy-induced airway inflammation and lung injury were assessed by histopathological analyses. Soluble PM2.5 extract exposure in vitro decreased the viability and increased apoptosis of airway epithelial cells. Soluble PM2.5 extract induced oxidative stress and enhanced pro-inflammatory factor expression by activating the NF-κB and MAPK signalling pathways, which were accompanied by reduced airway barrier function. The in vivo data demonstrated that PM2.5 exposure increased the effects of allergy sensitization after respiratory exposure to allergens, which led to the development of asthma. This study suggests that exposure to soluble PM2.5 extract contributes to airway barrier dysfunction. The soluble mediators generated by airway epithelial cells in response to PM2.5 exposure orchestrate the breaking of inhalational tolerance and sensitization to allergic antigens, leading to the exacerbated development of asthma. Unlabelled Image • A method that enables the assessment of the pathological effects of soluble PM2.5 extract on asthma was developed. • Soluble PM2.5 extract impaired airway epithelial morphology and physiology. • Soluble PM2.5 extract disrupted airway mucosal barrier functions. • Soluble PM2.5 extract inhibited immunotolerance and promoted experimental asthma. [ABSTRACT FROM AUTHOR]