A timing self-cleaning nanoherbicide: Design of triple-structure nanovectors for weed control and pesticide residues treatment

Pesticide residues treatment is a crucial issue for both agricultural production and environmental protection. In recent years, designing self-cleaning nanoformulations has emerged as a promising strategy for reducing pesticide residues in a convenient and cost-effective manner. However, traditional physical blending methods of photodegradation reagents with nanocarriers have limitations in terms of pesticide residue degradation efficiency and active ingredient efficacy. Here, a new type of timing self-cleaning nanoherbicide dicamba@mSiO2/ATA/TiO2 with a triple structure was fabricated. Dicamba, a widely used herbicide that was attracting increasing concern over its high efficiency and broad spectrum, was selected as the model herbicide and loaded on the mSiO2 shell. In the stage of pesticide release, the TiO2 and dicamba were separated by the timing-barrier. Therefore, the efficacy of dicamba was not affected by the photocatalyst. During the release process, the ATA layer continuously absorbed the reactive oxygen species (ROS) produced by TiO2 and was gradually degraded. Finally, the barrier was destroyed, and the residual dicamba in the carrier was degraded by TiO2. Compared with the traditional physical blending method, this triple structure avoided the degradation of active ingredients by photocatalysts during the pesticide release period. The experimental results suggested that this nanoformulation improved the efficacy of the herbicide, and reduced the pesticide residues, providing a new approach for self-cleaning nanopesticides research.