Hollow-structured resin nanoreactor with high-loading of Ag nanoparticles and void-confinement effect for efficient catalytic hydrogenation

The noble metal-loaded hollow nanostructures, serving as a representative cell biomimetic structural material, demonstrate competitive potentials in catalysis field due to their tailorable microenvironment effects and high catalytic efficiency. Herein, we successfully synthesized a novel Ag nanoparticle (Ag NPs)-loaded hollow resin nanoreactor with unique nanostructures, referred to as Ag@TA-HAFR/Ag, through a simple ethanol chemical scissoring process in conjunction with tannin (TA) coating technology. This strategy allowed the Ag NPs to simultaneously self-embed into the inner shell and outer surfaces of the hollow resin supports due to the presence of catechol-quinone redox self-catalysis reaction system, achieving small size (9.5 nm) and high loading amount (59.4 wt%) of Ag NPs. Notably, the resulting nanoreactor exhibited remarkable catalytic efficiency and universality; for example in hydrogenating methylene blue (MB) and methyl orange (MO) models, reaction rate constants (k) of up to 1.82 and 2.48 min⁻¹, respectively, were obtained, representing a fourfold and twofold increase compared to the control. The theoretical calculations demonstrate that the prepared nanoreactor possess a strong H₂ adsorption capacity that facilitates the void-confinement effect via providing an optimal microenvironment for catalytic hydrogenation. Furthermore, the TA coating layer and the shell encapsulation impart the Ag@TA-HAFR/Ag nanoreactor with a robust metal-support interaction and void limitation, dramatically enhancing their stability and recyclability. The present study offers a novel strategy for synthesizing advanced noble metal-loaded nanostructures, representing a significant advancement in the field of catalysis.