Explosion Strategy Engineering Oxygen-Functionalized Groups and Enlarged Interlayer Spacing of the Carbon Anode for Enhanced Lithium Storage.

Amorphous carbon monoliths with tunable microstructures are candidate anodes for future lithium-based energy storage. Enhancing lithium storage capability and solid-state diffusion kinetics are the precondition for practical applications. Transforming intrinsic oxygen-rich defects into active sites and engineering enlarged interlayer spacing are of great importance. Herein, a novel explosion strategy is designed based on oxalate pyrolysis producing CO and CO2 to successfully prepare lignin-derived carbon monolith (LSCM) with active carbonyl (C═O) groups and enlarged interlayer spacing. Explosion promotes the demethylation of methoxyl groups and cleavage of carboxyl groups to form C═O groups. CO2 etches carbon atoms in a short time to improve the heteroatom level, expanding the interlayer spacing. ZnC2O4 is decomposed at 400 °C, simultaneously producing CO and CO2, which constructs less C═O groups and large interlayer spacing. MgC2O4 is decomposed at 450 and 480 °C, staged-weakly producing CO and CO2, which constructs more C═O groups and larger interlayer spacing. CaC2O4 is decomposed at 480 and 700 °C, staged-uniformly producing CO and CO2, which constructs abundant C═O groups and largest interlayer spacing. The LSCM prepared by staged-uniform explosion exhibits high lithium storage capacity, superior rate capability, and cycling performance. The assembled lithium ion capacitor device achieves excellent energy/power densities of 78 Wh kg-1/100 W kg-1 and superior durability (capacitance retention of 8 4.6% after 20,000 cycles). This work gives a novel insight to engineer advanced oxygen-functionalized carbons for enhanced lithium storage.

Assessment of extraction options for a next-generation biofuel: Recovery of bio-isobutanol from aqueous solutions.

Isobutanol is a widely used platform compound and a raw material for synthesizing many high value-added compounds. It also has excellent fuel properties and is an ideal gasoline additive or substitute with a very broad development space. Isobutanol production by biological fermentation has the advantages of a comprehensive source of raw materials, low cost, environmental protection, and sustainability. However, it also has disadvantages such as many impurities, low isobutanol concentration, and difficulty separating the water + isobutanol azeotrope. Thus, it is necessary to explore an appropriate downstream separation process for the water + isobutanol azeotrope. K2CO3 with a strong salting-out effect was used as the salting-out agent, and the salting-out of isobutanol from aqueous solutions was investigated at 298.15 K. The effect of the initial salt concentration in the aqueous solution, the recovery of isobutanol, and the effect of dehydration were investigated in detail. The e-NRTL-RK model was employed to generate the binary parameters for isobutanol and water, and electrolyte pair parameters for water/isobutanol and ions to reproduce the phase diagram with high accuracy. The processes of solvent extractive distillation, and salting-out + distillation were simulated by Aspen Plus. The energy consumptions for the solvent-based and salting-out-based processes were compared. The salting-out + distillation process turned out to be more energy-saving than the solvent extraction process.

Facile synthesis of easily separated and reusable silver nanoparticles/aminated alkaline lignin composite and its catalytic ability.

Green synthesis of silver nanoparticles (AgNPs) has received increasing attention. In this study, AgNPs were prepared through in-situ reduction by aminated alkaline lignin (AAL). Compared with alkaline lignin (AL), AAL exhibited stronger reduction capacity (increased by 36%) due to the introduced amine groups and better water solubility. Moreover, the coordination effect of amine groups on AAL improved the binding force between lignin and AgNPs. The content of AgNPs in AgNPs/AAL composite were 2.4 times higher than that in AgNPs/AL, such content could be further increased through increasing the reduction pH or prolonging the heating time. The results of XPS, XRD and TEM showed that the AgNPs were spherical and monodisperse with an average particle size about 17 nm. Additionally, the size of AgNPs was affected by the amination degree of lignin. AgNPs/AAL exhibited good catalytic performance for the reduction of 4-nitrophenol to 4-aminophenol, and this compound could be easily recovered and reused for at least eight cycles.