A Comprehensive Review on Plant-Mediated Synthesis of Molybdenum- Based Nanoparticles

Abstract

Molybdenum-based nanoparticles (Mo-based NPs) represent a versatile class of inorganic
nanomaterials with applications spanning catalysis, optoelectronics, environmental remediation, and
nanomedicine. While physical and chemical synthesis routes offer precise dimensional control, they
often require toxic reducing agents, high thermal budgets, or hazardous organic solvents. Consequently,
plant-mediated "green" synthesis using phytochemical-rich extracts has emerged as a promising
alternative. However, the literature concerning plant-mediated Mo-based NPs remains fragmented,
methodologically inconsistent, and characterized by imprecise nomenclature—frequently grouping
metallic molybdenum (Mo0), molybdenum dioxide (MoO2), molybdenum trioxide (MoO3),
substoichiometric oxides (MoO????), and molybdenum disulfide (MoS2) under the generic label
"molybdenum nanoparticles."
This review provides a critical evaluation of plant-mediated Mo-based NP synthesis. We present a
transparent search strategy, clarify precursor speciation chemistry (MoO4
2− vs. Mo7O24
6−), detail
phytochemical complexation/reduction mechanisms, and establish a rigorous characterization
framework combining X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission
electron microscopy (TEM), dynamic light scattering (DLS), and zeta potential. Furthermore,
biological activities (antimicrobial, antioxidant, seed-priming) are critically evaluated using an
evidence-level grading scheme (Levels I–V) to separate demonstrated particle-specific efficacy from
phytochemical carryover artifacts. Finally, we propose a Quality-by-Design (QbD) development
framework, toxicological guidelines, and a standardized reporting checklist to facilitate the translational
development of phytogenic molybdenum nanomaterials.