Synergistic Effects of Morphology and Interface Engineering in WO3/TiO2 for Photocatalytic Hydrogen Generation.

Developing efficient catalysts for H2 release is significant in advancing sustainable energy systems. In particular, heterostructures based on WO3 and TiO2 stand out as promising photocatalysts owing to their tunable band structures, robust stability, and cost-effectiveness. This study investigates the impact of morphology and synthesis approach on the catalytic performance of WO3/TiO2 heterostructures for ammonia borane dehydrogenation. Two synthesis approaches, ex situ coupling of pre-synthesized WO3 with TiO2 and in situ growth of TiO2 on WO3, were systematically utilized to tailor the heterointerface and morphology. Controlled reaction conditions facilitated the formation of hexagonal-like WO3, thereby enabling the growth of distinct nanostructures. When integrated with TiO2, the morphology, heterojunction characteristics, and surface area were found to be highly dependent on the synthesis method. The in situ WO3/TiO2 heterostructure (∼0.302 µmol min-1) exhibited superior catalytic performance compared to ex situ method (∼0.258 µmol min-1). This enhancement is ascribed to the synergistic effects of increased surface area (21.81 m2g-1 for in situ sample compared with 11.33 m2g-1 for ex situ sample) and a more intimate heterointerface, which together promote effective charge separation and electron transfer. The findings highlight that not only morphology and composition but also the synthetic route play a critical role in determining catalytic efficiency.