Cellulose as an Inert Scaffold in Plasmon-Assisted Photoregeneration of Cofactor Molecules.

Plasmonic nanoparticles exhibit excellent light-harvesting properties in the visible spectral range, which makes them convenient material for the conversion of light into useful chemical fuel. However, the need for using surface ligands to ensure colloidal stability of nanoparticles inhibits their photochemical performance, due to the insulating molecular shell hindering the carrier transport. We show that cellulose fibers, abundant in chemical functional groups, can serve as a robust substrate for the immobilization of gold nanorods, thus also providing a facile way to remove the surfactant molecules. The resulting functional composite was implemented in a bioinspired photocatalytic process involving dehydrogenation of sodium formate and simultaneous photoregeneration of cofactor molecules (NADH - nicotinamide adenine dinucleotide) using visible light as an energy source. By systematic screening of experimental parameters, we compare photocatalytic and thermocatalytic properties of the composite and evaluate the role of palladium co-catalyst.