Single-step synthesis of nanostructured γ-alumina with solvent reusability to maximise yield and morphological purity

Insights of the chemical mechanism for the hydrothermal synthesis of nanostructured alumina are elucidated for the first time, demonstrating the effect of the NaOH : Al molar ratio not only on the resulting morphology of the material but also on the product yield. Highly uniform pure gamma-Al2O3 nanorods are synthesised under acidic conditions (pH < 4), while basic medium (pH > 9) lead to gamma-Al2O3 nanoplates. Maximisation of the morphological purity leads to a decrease in the overall aluminium yield which can be overcome by successful reusability of the synthesis medium in an effort to increase efficiency (yield and productivity) and minimise waste production towards feasible large-scale manufacturing of nanostructured materials.