Pd Nanoparticles on Melamine Sponges for Recyclable and Scalable Solar-Thermal Catalysis in Suzuki Coupling Reactions

Solar-thermal materials directly convert sunlight into heat, enabling the heating of reaction solutions without relying on electricity or fossil fuels. Although eco-friendly solar-thermal Suzuki coupling catalysis has recently been reported, its scalability must be enhanced for practical synthesis applications. In this study, an eco-friendly and scalable Suzuki coupling catalysis system was demonstrated using Pd nanoparticle monolayer-coated sponges, which exhibit exceptional solar-thermal and catalytic activities under multiphasic reaction conditions. The product mass per illuminated area was improved significantly compared with the earlier solar-thermal catalysis system. Gram-scale Suzuki coupling catalysis with Pd nanoparticle monolayer-coated sponges under simulated 1 sun illumination over an area of 3.14 cm2 was demonstrated successfully without the use of additional energy for solvent heating. The multicycle use of solar-thermal heating and heterogeneous catalytic activities of Pd nanoparticle monolayer-coated sponges was also demonstrated.