Three-Dimensional Carbonaceous Aerogels Embedded with Rh-SrTiO₃ for Enhanced Hydrogen Evolution Triggered by Efficient Charge Transfer and Light Absorption

Photocatalytic and photoelectrocatalytic hydrogen generation from water splitting by utilizing the visible spectrum of sunlight has been recognized as one of the promising energy conversion applications. Herein, we report the three-dimensional (3D) superstructure of g-C3N4 and reduced graphene oxide embedded with Rh-doped SrTiO3 nanoparticles as ternary aerogels for efficient hydrogen production. The optimized aerogel exhibits high competency for visible light harvesting due to the unique 3D morphology and shows excellent hydrogen evolution performance with quantum efficiencies of 51.1 and 26.9% at 450 and 600 nm monochromatic wavelengths, respectively. The 3D arrangement of integrated components helps in enhanced light absorption due to multiple reflections of incident light within the system and provides a high surface area with abundant reaction sites. Moreover, the ternary heterojunction facilitates efficient charge transfer owing to the suitable band positions of each component as evidenced by fluorescence lifetime, photocurrent, and impedance spectroscopic measurements, resulting in enhanced photocatalytic performance. In addition, the photoelectrocatalytic hydrogen evolution activity reveals the multifunctional nature of the synthesized catalysts. Thus, the hybrid design of the photocatalytic system realizes efficient hydrogen production in suspension and demonstrates the potential of aerogel-based materials as next-generation photocatalysts.