Design of a Pd/SWCNTs/TiO₂ Photocatalyst for Enhancing Cross-Coupling Reactions by Assistance of Surface Plasmon Resonance

The environmentally friendly and economical production of pharmaceutical and quasi-pharmaceutical compounds has emerged as a significant challenge within the pharmaceutical and agricultural industries. Therefore, designing plasmonic catalysts for synthesizing these compounds under simulated solar light presents a promising approach. Herein, a photocatalyst based on a Pd/SWCNTs/TiO₂ heterostructure is described for facilitating photocatalytic Suzuki and Stille coupling reactions under visible-light irradiation. Initially, the palladium (Pd) nanostructure was created in a cubic form, as verified by transmission electron microscopy (TEM) images. Subsequently, P-25 and SWCNT nanostructures were integrated onto the surface of Pd to create a Pd/SWCNTs/TiO₂ heterostructure aimed at enhancing the plasmonic absorption within the visible spectrum. The visible plasmonic absorption of Pd/SWCNTs/TiO₂ promoted the transfer of hot carriers from SWCNTs/TiO₂ to Pd, thereby improving the catalytic reactions occurring on the surface of the Pd metal. Consequently, our proposed photocatalyst indicated outstanding efficacy in the synthesis of biaryl compounds under 20 W light-emitting diode (LED) illumination. Our research demonstrated that the suggested photocatalyst is capable of being reused for up to five cycles, which could pave the way for synthesizing pharmaceutical and quasi-pharmaceutical compounds under simulated solar light.