Molybdenum disulfide (MoS2)-based transition-metal chalcogenides are considered to be cost-efficient, environmentally-friendly, and stable materials in the application of electrocatalytic hydrogen production.

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Modifying non-precious metal porphyrins at the meso-position is sufficient to further improve the ability to activate O2 and the selectivity of the corresponding redox products. In this study, a crown ether-appended Fe(III) porphyrin complex (FeTC4PCl) was formed by replacing Fe(III) porphyrin (FeTPPCl) at the meso-position. The reactions of FeTPPCl and FeTC4PCl catalysed by O2 oxidation of cyclohexene under different conditions were studied, and three main products, 2-cyclohexen-1-ol (1), 2-cyclohexen-1-one (2), and 7-oxabicyclo[4.1.0]heptane (3), were obtained. The effects of reaction temperature, reaction time, and the addition of axial coordination compounds on the reactions were investigated. The conversion of cyclohexene reached 94% at 70 °C after 12 h, and the selectivity toward product 1 was 73%. The geometrical structure optimization, molecular orbital energy level analysis, atomic charge, spin density, and density of orbital states analysis of FeTPPCl, FeTC4PCl, as well as the oxygenated complexes (Fe-O2)TCPPCl and (Fe-O2)TC4PCl formed after adsorption of O2, were carried out using the DFT method. The results of thermodynamic quantity variation with reaction temperature and Gibbs free energy variation were also analysed. Finally, based on experimental and theoretical analysis, the mechanism of the cyclohexene oxidation reaction with FeTC4PCl as a catalyst and O2 as an oxidant was deduced, and the reaction mechanism was obtained as a free radical chain reaction process.

Designing interfacial structure is an essential but challenging approach to regulating electronic structures to develop favorable bifunctional oxygen electrocatalysts in Zn-air batteries (ZABs). We utilize a facile one-step sintering strategy for preparing Co2P/Co3Fe7 interfacial nanoparticles encapsulated in N-doped carbon nanotubes (Co2P/Co3Fe7@N-C). The obtained Co2P/Co3Fe7@N-C electrocatalyst exhibits significant bifunctional oxygen evolution/reduction reaction (OER/ORR) activity (ΔE = 0.61 V), better than that of Pt/C + Ir/C (ΔE = 0.69 V) and compete with other previously report electrocatalysts. The density functional theory results reveal that the synergistic coupling effect and interfacial electronic interaction between Co2P and Co3Fe7 play a key role in boosting bifunctional ORR/OER efficiency. Remarkably, Co2P/Co3Fe7@N-C-based liquid ZABs exhibit excellent performance with higher power density (152.3 mW cm− 2) and longer cycle stability (1596 cycles) than the Pt/C + Ir/C-based ZABs (105 mW cm− 2; 882 cycles). Interestingly, the connected in series of Co2P/Co3Fe7@N-C-based liquid ZABs can be powered emitting diodes (LEDs) and blue LEDs display panel, indicating the possibility of practical application. It can be predicted that our present work opens a new pathway for rationally designing superior bifunctional oxygen electrocatalysts for rechargeable metal-air batteries through interfacial engineering.