(410b) Photocatalytic C-C Coupling Reactions of Terminal Alkynes Using Copper Oxide-Based Mie Resonator Photocatalysts

Carbon-carbon (C-C) coupling reactions have historically depended on palladium (Pd) catalysts in homogeneous systems.^1,2 However, the increasing demand for sustainable and scalable alternatives has shifted focus toward heterogeneous photocatalysts, particularly metal nanoparticles (e.g., Au, Ag, Cu), due to their substantial plasmonic field enhancement under light irradiation. Despite their promise, plasmonic metal nanoparticles (PMNs) face limitations such as thermal losses, short charge carrier lifetimes, and challenges in large-scale production.

This study introduces Mie resonator nanoparticles (MRNPs) as a promising alternative to plasmonic metal nanoparticles (PMNs), focusing on CuO and Cu₂O nanostructures along with their hybridized CuO-Pd and Cu₂O-Pd counterparts. These photocatalysts, incorporating catalytically active Pd within the MRNP framework, were assessed using the oxidative homocoupling of phenylacetylene (PA) as a benchmark reaction. All four catalysts - CuO-Pd, Cu₂O-Pd, CuO, and Cu₂O - exhibited significant catalytic potential. The incorporation of Pd notably accelerates the reaction, enabling complete conversion in a shorter time under broadband illumination (300 – 2000 nm), which represents the solar energy spectrum, underscoring the superior catalytic performance of CuO-Pd and Cu₂O-Pd. Meanwhile, CuO and Cu₂O serve as cost-effective and environmentally sustainable alternatives by eliminating the dependency on expensive and toxic metals such as Pd while still achieving full coxdcfnversion. Additionally, these catalysts function efficiently under base-free conditions, ensuring minimal waste production and enhancing the overall sustainability of the process.

References

(1) Addanki Tirumala, R. T. et. al Green Chem. 2019, 21 (19), 5284–5290.

(2) F. Pary, F.; Tirumala, R. T. et.al. Catalysis Science & Technology 2021, 11 (7), 2414–2421.