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Growing concerns about environmental pollution and future food supplies have encouraged the development of controlled release formulation of pesticides. Porous hollow silica (PHS) is an ideal carrier to prepare pesticide microcapsule due to its hollow structure, high surface area, and biocompatibility. However, the cumbersome preparation process of pesticide microcapsule based on PHS severely restricted its extensive development and application in pesticide products. Herein, an improved soft-template method for preparing pesticide loaded PHS was developed by using newly prepared tributylhexadecylphosphonium dicyanamide [P44416][N(CN)2] as the solvent and soft-template agent. The model pesticide prochloraz (PRO) was entrapped inside PHS in situ without loading process during the preparation process and a core–shell structure sphere (PRO@PIL-PHS-PEC microcapsule) was obtained by coating PRO@PIL-PHS with pectin in solution through electrostatic adsorption. The obtained PRO@PIL-PHS-PEC microcapsules had high drug encapsulation efficiency and good photostability with pectinase and pH responsive release properties. Plate antagonism tests and pot trials indicated that the PRO@PIL-PHS-PEC had a significant long-term control efficacy against S. sclerotiorum and no adverse impact on the growth of rapeseed plant. The prepared PRO@PIL-PHS-PEC could effectively reduce the use of pesticides by significantly improving the effective utilization rate and efficacy of pesticides. The simple and green method for synthesis of PRO@PIL-PHS-PEC based on PIL would have great potential for large-scale application of controlled release formulation in the field of pesticides.

Smart core–shell nanocarriers can release pesticides in response to stimuli from the microenvironment associated with pests and the physiological behaviors of protected crops. In this work, a smart nanocarrier (MIL-101(Fe)@silica) with dual functions of site-specific delivery and plant nutrition was fabricated to deliver chlorantraniliprole (CAP) for sustainable pest management. The results showed that the developed CAP@MIL-101(Fe)@silica with a size of approximately 270 nm had a stable core–shell nanostructure with a highly crystallized regular octahedron. The photostability of the drug loaded in the carrier under UV-light irradiation was 16.5 times higher than that of technical CAP. The introduction of the silica shell prevented the premature escape of CAP from the MIL-101(Fe) core in the environment and endowed the developed nanohybrid carrier with base-triggered release properties. In a laboratory bioassay, CAP@MIL-101(Fe)@silica had favorable insecticidal activity (LC50 = 0.389 mg/L) in controlling Plutella xylostella larvae. After fourteen days of spraying in the greenhouse experiment, the mortality of the CAP@MIL-101(Fe)@silica treatment (86%) against P. xylostella larvae was significantly higher than that of the CAP suspension concentration treatment (36.7%). In addition, MIL-101(Fe)@silica was safe for crops and could enhance the crop fresh weight and dry weight by 18.6–19.6% and 4.8–17.7%, respectively. Therefore, MIL-101(Fe)@silica could be used as a biocompatible carrier for site-specific pesticide delivery and simultaneously as a fertilizer for crop growth, which would be a novel route for the development of a precise pesticide delivery nanoplatform.

Biological nitrogenases exhibit superior nitrogen fixation efficiency owing to their unique multi-iron metallocluster (Fe2+3Fe3+4M3+, M = Mo, V, Fe) coordinated by organic polypeptide. Herein, we design a kind of metal organic framework (MOF) photocatalyst, MIL-53(FeII/FeIII) (MIL = Material from Institute Lavoisier), in which the FeII and FeIII constitute the mixed-valence metalloclusters to mimic the Fe2+ active sites and high-valence metal ions in nitrogenases, respectively. Both the FeII and FeIII are coordinated by organic ligands (terephthalic acid), which afford the electron transfer chains as well as the support of monodispersed FeII active sites. The FeIII in MIL-53(FeII/FeIII) is partly in-situ reduced into FeII by ethylene glycol (EG) via one-step solvothermal method, and the FeII/FeIII ratio is regulated from 0.18:1 to 1.21:1 by varying the EG content. Our results show that the FeII/FeIII ratio can significantly affect the photocatalytic activity and structure stability, and MIL-53(FeII/FeIII)-1 with optimal FeII/FeIII ratio (1.06:1) achieves the highest ammonia evolution rate up to 306 μmol h−1 g−1, nearly 10-fold higher than that of other framework-based materials, while remaining stable after 24 h irradiation. Such nitrogenase-like design in MIL-53(FeII/FeIII) endows the efficient electron transfer, exposed active sites, and in particular rational synergy between the catalytic function and non-catalytic function. This work may open a new avenue to the rational design of nitrogen fixation photocatalysts based on framework materials.