Controlled fabrication of novel zirconia nanoparticles with tailored size, morphology, crystal phases, surface properties, and acidity via Indonesian Boehmeria virgata-mediated eco-friendly synthesis

Green synthesis of ZrO₂ NPs from plant sources has gained significant attention due to its advantages, such as eco-friendly and low-cost production compared to chemical synthesis methods. The objectives of this work were to study the characteristics of green synthesized ZrO₂ NPs using three types of Boehmeria virgata leaf extracts in n-hexane (ZrO₂–H), methanol (ZrO₂-M), and water (ZrO₂–W) at various calcination temperatures (500, 700, and 900 °C). ZrO₂ NPs with different structures, morphologies, surface properties, and acidity were fabricated through an eco-friendly synthesis method using three types of Indonesian B. virgata leaf extract at various calcination temperatures. The resulting ZrO₂ NPs exhibited monoclinic and tetragonal phases, while a tetragonal-dominated structure was detected on ZrO₂–H 700, ZrO₂-M 700, and ZrO₂-M 900 NPs. SEM images showed that ZrO₂–H and ZrO₂-M NPs possessed homogenous nanospheres shape, whereas the combination of nanoflakes and nanospheres was observed in ZrO₂–W NPs. Based on the analysis of TEM micrographs, the average nanoparticle sizes of ZrO₂–H, ZrO₂-M, and ZrO₂–W at calcination temperatures of 900 °C were determined to be 16.02 nm, 34.63 nm, and 17.63 nm respectively. The formed ZrO₂ NPs prepared using BVLEs, exhibited a specific surface area ranging from 11.32 to 58.86 m²/g, a pore volume ranging from 0.058 to 0.183 cm³/g, and a pore diameter ranging from 9.85 to 58.65 nm. The acidity of ZrO₂ NPs ranged from 0.0397 mmol/g up to 1.6045 mmol/g. The calcination temperature influenced the XRD crystallite size, surface texture (specific area and porosity), and acidity of ZrO₂ NPs mediated by BVLEs. This green and simple synthesis method offers an alternative technique for forming highly valuable ZrO₂ NPs compared to chemical synthesis methods.