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In this paper, quantum chemical calculations and Gaussian 09 software were used to investigate the similarities and differences in the reactive sites of different fatty acids. The molecule structures of linoleic acid (LA) and four conjugated linoleic acid (CLA) were analyzed at the level of density functional theory. Molecular geometries and energies, frontline molecular orbitals, and surface electrostatic potentials were also analyzed. The results showed that the reactive of LA and CLA among the five fatty acids were all near the –C = C– structure and the carboxyl hydrogen atom, 9c, 11t CLA and 10t, 12c CLA were more reactive compared with 9t, 11t CLA, 10t, 12t CLA. This study can provide a theoretical basis for revealing the relationship between different structures and properties of fatty acids and also provide a guidance for the selection of fatty acids in the oil and fat industry. Practical Applications: This experiment compares the differences between the reactive sites of CLA and the four CLAs at the molecular structure level, which can be used to deepen the understanding of the structure‐property relationship of different fatty acids and also provides a theoretical basis for the selection of fatty acids in the food and oil industry. [ABSTRACT FROM AUTHOR]

• Single atom catalyst with Co-N 4 coordination has been precisely synthesized. • The interconnected 2D network can alleviate the formation of Li-dendrites. • Co-N 4 center suppress the shuttle effect and reduce the reaction energy barrier. • The correlation between the Co-N 4 sites and catalytic activity is deciphered. • The batteries exhibit superior electrochemical performance. Developing electrocatalyst to ameliorate the shuttling effect of lithium polysulfides (LiPSs), sluggish sulfur redox reaction kinetics and the rampant dendrite growth is of paramount importance for lithium-sulfur (Li-S) batteries. Yet still, the utilization of the most mainstream traditional metal electrocatalytic nanoparticles is far below expectation. Herein, we engineer an exclusive single-atom catalyst with planar Co-N 4 coupling of nitrogen-doped graphene mesh (SA-Co/NGM) to achieve exceptional atom utilization efficiency for catalytic conversion of LiPSs. High surface area and ultra-thin two-dimensional texture can not only accommodate high concentration monodispersed lithiophilic atomic Co sites, but also guarantee homogenize high-flux Li ion transport, alleviating the formation of Li-dendrites. Critically, the maximized exposure of Co-N 4 as a regulator in sulfur electrochemistry can conspicuously suppress the shuttle effect and accelerate bidirectional sulfur redox kinetics via electron delocalization, as demonstrated by a judicious combination of electro-kinetic analysis, in situ spectroscopy and density functional theory (DFT) computations. As expected, the batteries based on a SA-Co/NGM modified separator achieve an ultrahigh rate capability, exceptionally long cycle life and a distinguished favorable areal capacity under high sulfur loading. This work provides a rational design of single-atom catalysts for kinetics-boosted electrocatalysis towards long-lasting Li-S batteries. [ABSTRACT FROM AUTHOR]

• A three-dimensional Ni,Co-embedded CNT-coated N-doped hollow porous carbon (Ni/Co-CNT/NHPC) cathode has been designed and prepared for lithium-sulfur battery. • The Ni/Co-CNT/NHPC-S cathode possesses a high specific capacity of 1352 mA h g-1 and an excellent cycle stability at 1 C with low capacity decay of 0.094% per cycle over 500 cycles. • The mechanism of suppressing the shuttle effect on the cathode materials is discussed by analyzing adsorption experiments and density functional theory（DFT）calculation. Lithium-sulfur (Li-S) batteries have attracted great attentions due to their high specific capacity. However, the poor cycle stability caused by polysulfide shuttles, volume expansion and formation of lithium dendrites limit their practical applications. In the present work, to tackle the poor stability and unstable rate capability, a MOF-doping strategy is developed to construct a hollow porous carbon framework，which consists of Ni, Co particles and CNT on a N-doped shell surface (Ni/Co-CNT/NHPC). This hollow framework increases the load of S, slows down the volume changes, and can physically entrap soluble polysulfide. It is found that the CNT-coated network structure is beneficial for optimizing the conductivity and wettability of the material, which accelerates the reaction kinetics. Moreover, synergistic effect of abundant defects and Ni, Co nanoparticles strengthens the chemisorption of polysulfides, which suppresses the shuttle effect. As a consequence, the Ni/Co-CNT/NHPC-S cathode harvests a high specific capacity (1352 mA h g-1), and shows an excellent cycling stability at 1 C with low capacity decay of 0.094% over 500 cycles. [ABSTRACT FROM AUTHOR]

The fabricated VS 4 /Ni 3 S 2 /NF NBs was prepared by self-templated strategy, with exposed abundant hetero-interfaces and high active disulfide (S 2 2-) sites. The density functional theory revealed the reversible conversion catalysis mechanism of bridge S 2 2- during HER process, jointly promoting the HER performance. [Display omitted] • A novel VS 4 nanoparticle decorated Ni 3 S 2 nanobelt array was synthesized via one-step organic ligand-assisted solvothermal method. • The abundant disulfide (S 2 2-) moieties grafted on the hetero-interfaces of VS 4 /Ni 3 S 2 led to strong electronic interaction and promote the chemisorption of H-containing intermediates. • The density functional theory reveals the reversible conversion catalysis mechanism about disulfide (S 2 2-) sites during HER process. • The findings provide fresh insights for developing potential polysulfides as high-performance hydrogen-evolving electrocatalysts from water splitting. Elaborate and rational design of cost-effective and high-efficiency non-noble metal electrocatalysts for pushing forward the sustainable hydrogen fuel production is of great significance. Herein, a novel VS 4 nanoparticle decorated Ni 3 S 2 nanobelt array in-situ grown on nickel foam (VS 4 /Ni 3 S 2 /NF NBs) was prepared by a self-templated synthesis strategy. Benefitting from the unique nanobelt array structure, abundant highly active bridge S 2 2- sites and strong electronic interaction between VS 4 and Ni 3 S 2 on the heterointerface, the integrated VS 4 /Ni 3 S 2 /NF NBs exhibited excellent electrocatalytic hydrogen evolution activity and robust stability. The density functional theory (DFT) further revealed the reversible conversion catalysis mechanism of bridging S 2 2- sites in VS 4 /Ni 3 S 2 /NF NBs during HER process. Notably, bidentate bridging S S bonds as the predominant catalytically active centers can spontaneously open once H adsorbed its surface, leading to the aggregation of negative charges on S atoms and thus facilitating the generation of H* intermediates, and spontaneously close when H* desorption is going to form H 2. Our work provides fresh insights for developing potential polysulfides as high-performance hydrogen-evolving electrocatalysts for prospective clean energy production from water splitting. [ABSTRACT FROM AUTHOR]