Stomata-inspired smart bilayer catalyst with the dual-responsive ability, capable of single/tandem catalysis

Abstract

This study is aimed at addressing the present challenges of self-controlled processes in tandem catalysis. Inspired by the opening and closing switchable behaviors of stomata in plant leaves arose by temperature, the objective is met by originally developing a “smart” tandem catalyst capable of crossing-response properties. The catalyst consisted of two unique functional layers where each may self-govern one coupled process. The first layer was fabricated with a negatively-thermosensitive imprinted polymer and encapsulated metal nanoparticles (PDEA-co-PAM/Ag) which were responsible for a catalytic reduction process. The second layer was made of a positively-thermosensitive polymer (PVI-co-PAMPS) with acidic groups, which were capable of a catalytic hydrolysis process. At low temperatures, this catalyst would conduct only catalytic reduction because of the open channel in the first layer. In middle temperatures, the catalyst would run the tandem processes from catalytic reduction to hydrolysis because of the open channels in both the two layers. At higher temperatures, the catalyst only catalyzed hydrolysis because of the closed channel in the first layer. In this way, the smart bi-layer catalyst achieved the single/tandem/single catalysis featured with a dual temperature-responsive switch. The novel protocol not only provides a new solution to complicated catalytic processes but also inspires the further application of smart polymers in a broader spectrum of areas.