Mechanism insight of dual synergistic effects of plasmonic Pd-SrTiO${}_3$ for enhanced solar energy photocatalysis

This study presents the integration of UV-active semiconductor with plasmonic noble metal nanoparticles for enhanced solar energy photocatalysis. Nanocubes strontium titanate (SrTiO${}_3$) is synthesized via a simple hydrothermal process. Then palladium (Pd) nanoparticles will be deposited onto the surface of SrTiO${}_3$ by simple photochemical deposition route. The deposition of plasmonic Pd nanoparticles significantly increased the light absorption, especially in visible and near-infrared region and enhanced charge separation efficiency. The photocatalytic performance of Pd-deposited SrTiO${}_3$ is assessed by photodegradation of bisphenol A (BPA) and 4-chlorophenol (4CP) under solar light. The results confirm that the existence of Pd nanoparticles in SrTiO${}_3$ has improved the photocatalysis efficiency compared to pure SrTiO${}_3$. The higher weight percentage of Pd loading achieved better photocatalytic performance compared to lower weight percentage of Pd loading. This improvement can be deduced from the dual localized surface plasmon resonance effects that led to higher photoresponse and generation of free electrons. Moreover, the existence of Pd nanoparticles further retards the recombination rate of electron and hole pairs. This leads to the excess presence of electrons that contributed to the formation of active radicals that enhanced the oxidation of BPA and 4CP. Thus, this study will provide a new mechanism insight and approach to modify visible and near-infrared light-driven photocatalysts in degrading various organic pollutants.