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Low‐cost bifunctional nonprecious metal catalysts toward oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are critical for the commercialization of rechargeable zinc–air batteries (ZABs). However, the preparation of highly active and durable bifunctional catalysts is still challenging. Herein, an efficient catalyst is reported consisting of FeCo nanoparticles embedded in N‐doped carbon nanotubes (FeCo NPs‐N‐CNTs) by an in situ catalytic strategy. Due to the encapsulation and porous structure of N‐doped carbon nanotubes, the catalyst shows high activity toward ORR and excellent durability. Furthermore, to enhance the OER activity, CoFe‐layer double hydroxide (CoFe‐LDH) is coupled with FeCo NPs‐N‐CNTs by in situ reaction approach. As the air electrode for rechargeable ZABs, the cell with CoFe‐LDH@FeCo NPs‐N‐CNTs catalyst exhibits high open‐circuit potential (OCP) of 1.51 V, high power density of 116 mW cm−2, and remarkable durability up to 100 h, demonstrating its great promise for the practical application of the rechargeable ZABs.

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Starch laurate, a kind of high fatty acid starch ester, was directly produced by mechanical activation (MA)-assisted solid-phase synthesis (MASPS) technology with a customized stirring ball mill as reactor. The starch laurates with different degrees of substitution (0.0148−0.0412) were obtained under different reaction conditions. Fourier transform infrared spectroscopy confirmed that starch ester had been successfully produced by MASPS attributed to active hydroxy groups induced by MA. X-ray diffractometry and scanning electron microscopy showed that MA and esterification significantly disrupted the morphology and crystal structure of starch. Water absorption of starch was increased by MA but decreased by the introduction of laurate groups. Viscosity of starch was obviously reduced after both the processes of MA pretreatment and MASPS. The successful synthesis of starch laurate without the use of solvent and additives suggested that MASPS was a fast, simple, and green method for the production of high fatty acid starch esters.

Esterification is an important chemical modification for the preparation of natural cellulose-based materials.However, esterification of cellulose is commonly carried out in organic solvents, which reduces the economic and environmental feasibility of the synthetic technologies. Herein we report a novel technology for the production of cellulose esters, which combines mechanical activation (MA) and esterification in a stirring ball mill under solid phase conditions without the use of solvents. With the use of acetic anhydride as co-reactant and fatty acids as long chain esterifying agents, 1 H and 13 C NMR measurements confirmed that both acetyl and long chain fatty acyl groups were successfully grafted on cellulose by the technology of MA-assisted solid phase synthesis (MASPS). The factors which contributed to the successful preparation of cellulose esters were: the formation of highly reactive mixed acetic-long chain fatty acid anhydride, the generation of active hydroxyl groups in cellulose, the weakening of the steric effect of long chain fatty acids, and the improved contact between reagents and cellulose which were first induced by intense milling. It also showed that the reactivity of fatty acids and the degree of substitution (DS) of fatty acyls decreased with the increase in their chain length, and the long chain fatty acylium ions preferred to react with the more reactive hydroxyl group in the anhydro glucose unit of cellulose. Moreover, Fourier transform infrared spectroscopy, X-ray diffractometry, and scanning electron microscopy analyses were used to measure the changes in chemical structure, crystal structure, and surface morphology of the cellulose before and after esterification by MASPS, respectively. The results indicate that this green, simple, and efficient technology is suitable for the direct production of cellulose esters with long chain substituents.