Morphology engineered spatial charge separation in superhydrophilic TiO₂/graphene hybrids for hydrogen production

Spatial charge separation is achieved by morphologically tuning TiO₂ nanomaterials along with graphene by a hydrothermally modified sol-gel synthetic route. Morphology engineered TiO₂ is constructed between nanocuboids with high energy {010}/{100} and {001}facets, and nanoellipsoids exposing low energy {101} facets. In situ grown titania hybridized with graphene (0.1% w/w) introduced chemical linkages as affirmed by XPS, Raman and FTIR studies. PL and TCSPC measurements greatly supported interfacial charge separation and reduced recombination rate in the hybrids. Photocatalytic studies determined that hybrids with TiO₂ nanoellipsoids favoured hydrogen production as high as 18,266.6 μL/gm/L/hr under solar light illumination. While the hybrid with shared morphology of nanoellipsoids and nanocuboids for TiO₂ exhibited comparatively less H₂ production (13,967 μL/gm/L/hr) but displayed extreme photoinduced wettability of ~0° within 10 min of light irradiation. The divergence in the performance of morphologically tuned hybrids is explained using a plausible mechanism, assisted by photoconductivity and Hall-Effect measurements.