Synergistic Effect\nof Dendritic Fibrous Nanosilica\nand In<sub>2</sub>O<sub>3</sub> Photocatalysts for Enhanced Visible-Light-Driven\nHydrogen Generation

Producing green hydrogen from water using photocatalysts\nand solar\nenergy is a pivotal strategy in combating climate change by adopting\nrenewable energy sources. Herein we report the synthesis of a novel\ndendritic fibrous nanosilica and In<sub>2</sub>O<sub>3</sub> composite\n(DFNS/In<sub>2</sub>O<sub>3</sub>) via a solvothermal method. Comprehensive\ncharacterizations of the crystal phase, morphology, and optical absorption\nproperties of DFNS/In<sub>2</sub>O<sub>3</sub> were conducted using\npowder X-ray diffraction, field emission scanning electron microscopy,\ntransmission electron microscopy, <sup>29</sup>Si cross-polarization\nmagic angle spinning nuclear magnetic resonance, UV–Vis diffuse\nreflectance spectroscopy, Brunauer–Emmett–Teller analysis,\nand thermogravimetric analysis. The formation of an interface between\nIn<sub>2</sub>O<sub>3</sub> nanoparticles and the DFNS surface facilitates\nthe charge separation, thereby improving the photocatalytic efficiency.\nThe DFNS/In<sub>2</sub>O<sub>3</sub> (30%) photocatalyst displayed\na remarkable 23-fold increase in the hydrogen generation rate (1067\nμmol h<sup>–1</sup> g<sup>–1</sup><sub>cat</sub>) compared to pristine In<sub>2</sub>O<sub>3</sub> (45.79 μmol\nh<sup>–1</sup> g<sup>–1</sup><sub>cat</sub>). This enhancement\nis attributed to the superior light harvesting capability of DFNS\nowing to multiple light scattering events and the effective dispersion\nof In<sub>2</sub>O<sub>3</sub> on the fibrous surface of DFNS, which\nimproves water diffusion and interaction with active catalytic sites.\nThis study presents a unique outlook on the development of new photocatalytic\nsystems, combining In<sub>2</sub>O<sub>3</sub> nanomaterials with\nan optimal band gap (2.8 eV) for photocatalytic water splitting and\nDFNS with its inherent high light harvesting capacity due to its fibrous\nnature and increased surface area.