Synergistic Effect of Dendritic Fibrous Nanosilica and In₂O₃ Photocatalysts for Enhanced Visible-Light-Driven Hydrogen Generation

Producing green hydrogen from water using photocatalysts and solar energy is a pivotal strategy in combating climate change by adopting renewable energy sources. Herein we report the synthesis of a novel dendritic fibrous nanosilica and In2O3 composite (DFNS/In2O3) via a solvothermal method. Comprehensive characterizations of the crystal phase, morphology, and optical absorption properties of DFNS/In2O3 were conducted using powder X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, 29Si cross-polarization magic angle spinning nuclear magnetic resonance, UV–Vis diffuse reflectance spectroscopy, Brunauer–Emmett–Teller analysis, and thermogravimetric analysis. The formation of an interface between In2O3 nanoparticles and the DFNS surface facilitates the charge separation, thereby improving the photocatalytic efficiency. The DFNS/In2O3 (30%) photocatalyst displayed a remarkable 23-fold increase in the hydrogen generation rate (1067 μmol h–1 g–1cat) compared to pristine In2O3 (45.79 μmol h–1 g–1cat). This enhancement is attributed to the superior light harvesting capability of DFNS owing to multiple light scattering events and the effective dispersion of In2O3 on the fibrous surface of DFNS, which improves water diffusion and interaction with active catalytic sites. This study presents a unique outlook on the development of new photocatalytic systems, combining In2O3 nanomaterials with an optimal band gap (2.8 eV) for photocatalytic water splitting and DFNS with its inherent high light harvesting capacity due to its fibrous nature and increased surface area.