Plasmon Induced Nano Au Particle Decorated over S,N-Modified TiO₂ for Exceptional Photocatalytic Hydrogen Evolution under Visible Light

Nano Au deposited mesoporous S,N-TiO2 (SNT) nanocomposites have been fabricated through deposition precipitation technique by employing urea as the hydrolyzing agent. To investigate the structural, optical, and electronic properties, the photocatalysts are characterized through X-ray diffraction (XRD), UV-vis diffuse reflectance spectra, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and photoelectrochemical measurements. Here in addition to the co-catalyst nature of nano Au particles, surface plasmon resonance (SPR) effect in visible region enhances the light harvestation ability as well as transfer electrons to the conduction band of SNT. Furthermore, easy channelization of photogenerated charge carriers through sulfate facilitated redox couple makes the system more potential towards H2 evolution. TEM study exhibits well interconnective morphology in the matrix which helps easy channelization of electrons in the SNT nanocomposites. The photocatalytic activities have been evaluated for hydrogen generation under the irradiation of visible light and an enhanced activity has been observed for the Au promoted SNT due to the presence of nano Au particles, that is, 3.5 nm. The hydrogen generation activity of 3Au-SNT is nearly 9 times higher than that of neat SNT, and the energy conversion efficiency was found to be 17.6 %.