Transmittance Polyacrylamide Hydrogel Composites With TiO 2 Quantum Dots as Photo‐Initiators for Photocatalytic Pollutant Degradation

ABSTRACT In this study, we present a transparent, recyclable hydrogel composite by integrating TiO 2 quantum dots (TDQDs) into a polyacrylamide (PAM) matrix, where the TDQDs function dually as photoinitiators and photocatalysts. The TDQDs were synthesized via a simple water‐bath method and facilitated rapid photopolymerization of PAM, forming a porous hydrogel with uniformly dispersed quantum dots (2–3 nm), as confirmed by SEM and HRTEM analyses. The resulting TDQD/PAM hydrogel demonstrated efficient photocatalytic degradation of methylene blue and methyl orange within approximately 2 h, outperforming conventional P25/PAM composites due to its superior light transmittance and nanoscale distribution of photocatalysts. Importantly, the hydrogel retained stable photocatalytic activity over seven consecutive cycles without regeneration, indicating excellent durability. Mechanistic studies revealed that TDQD generated reactive oxygen species, effectively degrading dyes with a tendency toward mineralization and reduced toxicity risk. This dual‐functional hydrogel offers a sustainable and scalable platform for advanced wastewater treatment and aligns with circular economy principles.