Dual‐Functional β‐Ga 2 O 3 Nanostuctures: Morphology‐Driven Advances in Photocatalysis and Cold Cathode Emission

ABSTRACT Dimensional shrinkage and morphology modulation of nanostructured β‐Ga 2 O 3 play a crucial role in regulating its photocatalytic and cold‐emission performances. In this work, β‐Ga 2 O 3 nanostructures were synthesized via calcination of gallium oxyhydroxide, prepared through a simple chemical route. Morphological control was achieved using polyvinylpyrrolidone (PVP) as a shape‐directing agent, which suppresses particle agglomeration and promotes controlled growth along specific crystallographic facets. In addition to conventional structural and morphological characterizations, the photocatalytic performance of Ga 2 O 3 systems was evaluated by time‐resolved UV–Vis absorption spectroscopy during degradation of eosin B (EB) dye under UV irradiation. The porous β‐Ga 2 O 3 nanoflakes exhibited a significantly larger effective surface area and enhanced UV–Vis light absorption compared to irregularly shaped, agglomerated Ga 2 O 3 . Consequently, the nanoflake‐based β‐Ga 2 O 3 achieved a photodegradation efficiency of ∼99% within 30 min of UV‐exposure, markedly superior to that of the agglomerated Ga 2 O 3 counterpart (∼30%). Furthermore, the β‐Ga 2 O 3 nanoflakes demonstrated enhanced cold emission characteristics, attributed to their high aspect ratio, porous morphology, and increased density of emission sites. Overall, this study presents a facile, low‐cost, and environmentally benign strategy for tailoring the morphology of Ga‐based oxide nanostructures, enabling superior photocatalytic activity for wastewater remediation and improved cold‐cathode emission performance compared to commercially available gallium oxide.