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

Abstract

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-C 3 N 4 and reduced graphene oxide embedded with Rh-doped SrTiO 3 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.

Vacancy Engineering in Semiconductor Photocatalysts: Implications in Hydrogen Evolution and Nitrogen Fixation Applications

“…Depending on the bandgap ( E g ) of the semiconductor material, the light of different energies can be harvested from the sunlight irradiations and utilized for several photocatalytic reactions. [ 56 ] In this process, the absorption of light by the photocatalytic material takes place, provided the energy of incident photons should be equal to or greater than the bandgap of the material, i.e., E g ≥ hν . This absorption of light results in the excitation of electrons (e − ) from the valence band (VB) of the semiconductor photocatalyst to its conduction band (CB), leaving behind the holes (h + ) in VB as shown in Equation (1).…”

Photocatalysis and perovskite oxide-based materials: a remedy for a clean and sustainable future

“…, introduces the intra-band local states, making the doped SrTiO 3 a suitable photocatalyst. 100 The Ru doping introduces the intra-band energy state between conduction band (Ti 3d) and valence band (O 2p, Sr 4p). The ionic radius of Ru is greater than Sr and nearly equals Ti; therefore, the Ru substitutes Ti atom in SrTiO 3 .…”

Construction and investigation on perovskite-type SrTiO3@ reduced graphene oxide hybrid nanocomposite for enhanced photocatalytic performance

“…Among various photocatalysts, SrTiO 3 has garnered attention with compelling properties in photocatalysis [18]. Moreover, SrTiO 3 has been one of the potentials and well-known semiconductor photocatalysts owing to its low cost, high chemical stability, biocompatibility and comparable optical property with the standard TiO 2 photocatalyst [19,20]. However, the reported investigations showed a wide band gap of SrTiO 3 which respond only in the ultraviolet (UV) solar spectrum and consequently showed its limitations in practical applications.…”