Vermiculture-based molybdenum oxide nanoparticles synthesis, optimization, characterization and its impact on seed germination and seedling characteristics in green gram (Vigna radiata)

Here, we report the biosynthesis of molybdenum oxide (Mo₅O₁₄) nanoparticles (NPs) by co-precipitation methods using various vermiculture-based extracts and their impact on seed germination in Vigna radiata. The synthesis of Mo₅O₁₄ NPs was initially characterized by a color change from yellow to white and a surface plasmon resonance (SPR) peak at 360 nm in UV–visible spectroscopic analysis. In addition, X-ray diffraction (XRD) data revealed that the Mo₅O₁₄ NPs were crystalline with a tetragonal structure and a size of 35.32–41.86 nm. Furthermore, fourier transform infrared (FTIR) analysis of NPs absorption bands revealed the presence of unique functional groups, such as -OH stretching, CH₂ stretching, and primary amide groups, providing strong evidence that the native protein served to a reduce, cap, and stabilize Mo₅O₁₄ NPs. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images revealed that the ultrastructural profile of Mo₅O₁₄ NPs formed rod particles with an average particle length of 102 nm and width of 33 nm. The energy dispersive X-ray (EDX) pattern analysis confirmed the presence of Mo and O ions. Finally, the effects of Mo₅O₁₄ NPs on Vigna radiata seed fresh and dry biomass characteristics, root and shoot length, and seed germination were investigated, and it was found that a significant increase in the seed germination rate of all seven vermiculture-based Mo₅O₁₄ NPs was observed at 200 ppm. Consequently, our work provides a step forward in the development of vermiculture-based Mo₅O₁₄ NPs as a promising green agrochemical nano-fertilizer.