Synergistic effect of dendritic fibrous nanosilica and In₂O₃ photocatalysts for enhanced visible-light-driven hydrogen generation

Abstract

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^–1_cat) compared to pristine In₂O₃ (45.79 μmol h^–1 g^–1_cat). 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.