Au-Loaded Resorcinol–Formaldehyde Resin Photocatalysts: Hollow Sphere Structure Design and Localized Surface Plasmon Resonance Effect Synergistically Promote Efficient Nicotinamide Adenine Dinucleotide (NADH) Regeneration

For industrial enzymatic catalysis, efficient regeneration of nicotinamide adenine dinucleotide (NADH) is necessary. Herein, hollow resorcinol-formaldehyde resin nanospheres loaded with Au nanoparticles (HRF-Au) with shape-controllable nanostructures for photocatalysis were successfully prepared via the hard template method and photodeposition. As a novel photocatalyst, HRF-Au efficiently achieved a high NADH yield of 80.39% with a total reaction rate of 0.6 mmol·gcatalyst–1·h–1 under visible light illumination, which was four times higher than pure resorcinol–formaldehyde resin nanospheres (RF). Also, the photocatalytic system achieved high operational stability and faster rates of NADH production to the partial traditional enzymatic regeneration systems. This exceedingly good activity is partly due to the improvement of photoelectric properties of HRF-Au, which was confirmed by a series of characterization. More importantly, by finite element simulations and energy band structure determination, the hollow sphere structure and localized surface plasmon resonance effect induces the bending of the RF energy band to form a Schottky junction. These were conducive to the generation, separation, and migration of carriers, so as to improve the performance of photocatalytic regeneration of NADH. Our study will contribute to the development of materials with efficient photocatalytic NADH regeneration performance. Meanwhile, the photocatalytic NADH regeneration system could operate continuously and stably, and the significant reduction in byproducts and costs make this sustainable green technology have great potential in the future under both ecological and economical concerns.