Design-Directed Preparation of Cu–Cu ₂ O–CuO/Carbon Composite for Plant Protection and Growth

A design-directed process is used to prepare Cu-Cu 2 O-CuO/carbon composite particles of ∼1–2 μm in size. The composite particles are constituted by flower-petal-like features of Cu-Cu 2 O-CuO supported by carbon. They are composed of amorphous carbon (with C═O and surface-adsorbed −OH groups), as well as metallic Cu and cationic Cu (i.e., Cu in both Cu + and Cu 2+ states), which enables them to control fungal growth and nutrition in plants. The amounts of Cu and carbon in the composite particles are 20.19 at. % and 62.72 at. %, respectively. Antifungal activity and micronutrient supply of the composite particles are evaluated using a mycelial growth inhibition assay and through standard plant growth responses. Moderate zeta potential values of different test solutions of the composite particles in DI water help balance the stability and deposition of the composite particles onto fungal hyphae and seed surfaces, enabling their ultralow-dose efficacy in controlling fungal growth and stimulating plant growth.