The sulfur redox kinetics critically matters to superior lithium-sulfur (Li-S) batteries, for which single atom catalysts (SACs) take effect on promoting Li 2 S redox process and mitigating the shuttle behavior of lithium polysulfide (LiPs). However, conventional trial-and-error strategy significantly slows down the development of SACs in Li-S batteries. Here, the Li 2 S oxidation processes over MN 4 @G catalysts are fully explored and energy barrier of Li 2 S decomposition (E b ) is identified to correlate strongly with three parameters of energy difference between initial and final states of Li 2 S decomposition, reaction energy of Li 2 S oxidation and Li-S bond strength. These three parameters can serve as efficient descriptors by which two excellent SACs of MoN 4 @G and WN 4 @G are screened which give rise to E b values of 0.58 and 0.55 eV, respectively, outperforming other analogues in adsorbing LiPs and accelerating the redox kinetics of Li 2 S. This method can be extended to a wider range of SACs by coupling MN 4 moiety with heterostructures and heteroatoms beyond N where WN 4 @G/TiS 2 heterointerface is predicted to exhibit enhanced catalytic performance for Li 2 S decomposition with E b of 0.40 eV. This work will help accelerate the process of designing a wider range of efficient catalysts in Li-S batteries and even beyond, e.g. alkali-ion-Chalcogen batteries.

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Abietic acid was isolated by means of isomerization and amination reaction-crystallization coupled with ultrasonic wave. Isomerization rosin and ethanolamine were used as raw materials, 95% ethanol as recrystallization solvent, the effects of reaction temperature, reaction time, agitating velocity, ultrasound intensity and recrystallization times on the purity and yield of abietic acid were investigated. The suitable isolation conditions were obtained as follow: reaction temperature 30 °C, reaction time 40 min, agitating velocity 400 rpm, ultrasound intensity 300 W and freeze crystallization of amine salt three times. The purity and yield of abietic acid were 98.52% and 54.93% when the suitable conditions were used. And it was then characterization by its melting point, specific rotation, UV, FTIR and NMR, all evidence indicated that the purification product was abietic acid.

Electrocatalytic water splitting has recently surfaced as a promising method by transforming them into hydrogen fuel. [2] The bottleneck in the development of electrochemical water splitting technology is the oxygen evolution reaction (OER), which is the half reaction at the anode. [3] OER has very sluggish kinetics because it is a four proton-electron transfer process. [4] It is also a vital half-reaction for rechargeable metal-air batteries. [5] Therefore, efficient electrocatalysts are required to overcome the high OER overpotential. Currently, both RuO 2 and IrO 2 are regarded as the state-of-theart electrocatalysts for OER. [6][7][8] However, both of them show poor dissolution resistance under high anodic potential. [9,10] Moreover, their high price and scarcity make it vital to develop cost-effective, highly active, and durable electrocatalysts for OER. [11] Nanomaterial electrocatalysts are generally more efficient than their bulk counterparts due to larger specific surface areas and higher mass activities. Therefore, electrocatalysts with smaller size are normally desired for improved electrocatalytic performance. [12] For example, reducing the size of Cu nanoparticles can significantly increase its catalytic activity because of the increased low-coordination sites acting as active sites. [13] Likewise, size-dependent electrocatalytic activity has also been observed for Au nanoparticles. [14] However, it is still challenging Developing low-cost and efficient oxygen evolution electrocatalysts is key to decarbonization. A facile, surfactant-free, and gram-level biomass-assisted fast heating and cooling synthesis method is reported for synthesizing a series of carbon-encapsulated dense and uniform FeNi nanoalloys with a single-phase face-centered-cubic solid-solution crystalline structure and an average particle size of sub-5 nm. This method also enables precise control of both size and composition. Electrochemical measurements show that among Fe x Ni (1−x) nanoalloys, Fe 0.5 Ni 0.5 has the best performance. Density functional theory calculations support the experimental findings and reveal that the optimally positioned d-band center of O-covered Fe 0.5 Ni 0.5 renders a half-filled antibonding state, resulting in moderate binding energies of key reaction intermediates. By increasing the total metal content from 25 to 60 wt%, the 60% Fe 0.5 Ni 0.5 /40% C shows an extraordinarily low overpotential of 219 mV at 10 mA cm −2 with a small Tafel slope of 23.2 mV dec −1 for the oxygen evolution reaction, which are much lower than most other FeNi-based electrocatalysts and even the state-of-the-art RuO 2 . It also shows robust durability in an alkaline environment for at least 50 h. The gram-level fast heating and cooling synthesis method is extendable to a wide range of binary, ternary, quaternary nanoalloys, as well as quinary and denary high-entropy-alloy nanoparticles.