Visible light enhanced photosynthesis of C-C bonds using PdO/Pd@PEDOT nanocomposite

Abstract

Facile utilization of abundant and freely available solar energy in the production of fine chemicals is currently recognized as an effective strategy for sustainable chemical production. We are hereby reporting one of the best visible light active photocatalysts for C-C bond formation. The photocatalyst is a heterojunction nanocomposite of PdO/Pd with poly(3,4-ethylenedioxythiophene) (PdO/Pd@PEDOT HNC). It was synthesized via one pot chemical oxidative polymerization of EDOT with K2PdCl4. Uniform spherical morphology of the nanocomposite was achieved using a solvent assisted, and template free approach. PdO/Pd@PEDOT HNC consisted of very small Pd nanoparticles with dual oxidation states [here, Pd (II) and Pd (0)] embedded in the PEDOT matrix. It showed excellent electron-hole pair separation capabilities under visible light due to the formation of a straddling type of heterojunction between PdO and semiconducting PEDOT. PdO/Pd nanoparticles forms strong chemical interaction with PEDOT via Pd-O and Pd-S bonds in the HNC. These interactions make it a highly stable photocatalyst which can be recycled up to seven times without any significant loss of activities. Further, a novel route for the synthesis of uniform Pd4S nanostructures using a template free strategy could also be achieved.