Optimizing Hydrothermal Conditions for the Controlled Growth of La(OH)₃ and La₂O₃ Nanowires

Lanthanum hydroxide and oxide nanowires have been successfully synthesized using hydrothermal technique. This study systematically investigates the effects of hydrothermal aging temperature, time, and different alkaline sources (NH 3 , Na 2 CO 3 , NaOH, KOH) on the morphology and crystallinity of La(OH) 3 and La 2 O 3 nanowires. To our knowledge, this is the first comparative study examining the impact of these four alkaline sources in a controlled hydrothermal environment. The as‐prepared samples were characterized by X‐ray diffraction (XRD), field‐emission scanning electron microscopy (FE‐SEM), thermogravimetric analysis (TGA), and N 2 adsorption–desorption (BET) measurements. The results indicate that increasing hydrothermal temperature and time leads to thinner and longer La(OH) 3 nanowires, with diameters as small as 40 nm and lengths extending up to 3 µm. The average crystallite size increased from 11.6 nm to 18.9 nm with higher temperature and prolonged aging, while the BET surface area decreased from 35.4 to 17.2 m 2 /g. Ammonia‐based synthesis resulted in the highest surface area (25.8 m 2 /g) and total pore volume (0.083 cm 3 /g), whereas sodium carbonate yielded the lowest values (10.3 m 2 /g, 0.035 cm 3 /g). These findings emphasize the importance of optimizing hydrothermal conditions and selecting suitable alkaline sources to achieve the desired nanowire morphology and properties.