Quantum Dot-Embedded Hybrid Photocatalytic Nanoreactors for Visible Light Photocatalysis and Dye Degradation

Utilization of visible light to drive chemical transformations is a fascinating field of research and particularly important in the current socioeconomic context. However, bare photocatalysts often undergo photodegradation or agglomeration, which limits their recyclability. In this regard, designing robust and flexible artificial photocatalytic nanoreactors with embedded catalytic units finds tremendous importance in recent times. Herein, we utilized quantum dot (QD)-embedded coacervate nanodroplets (NDs) as photocatalytic nanoreactors for model chemical transformations, which are otherwise inefficient with bare QDs in bulk aqueous solution. Hybrid NDs fabricated from negatively charged CdTe QDs and positively charged poly(diallyldimethyl) ammonium chloride (PDADMAC) have been exploited as a confined host toward efficient visible light-driven photoredox transformation of ferricyanide (Fe3+) to ferrocyanide (Fe2+) and photocatalytic dye degradation of rhodamine B and methylene blue. The present NDs display excellent recyclability without any appreciable decrease in the conversion yield and reaction kinetics. Our findings suggest the involvement of individual QDs embedded within these NDs as the active photocatalytic site for these transformations. The observed photocatalytic activity of the QD-embedded NDs arises due to the combined effect of surface charge modulation of embedded QDs and nanoconfinement inside the nanoreactor. The present study paves the way for designing next-generation photocatalytic nanoreactors toward a vast array of photochemical conversions involving semiconductor nanoparticles.