Mixed-phase electrodeposited MoS2 quantum dots for solar-driven dye removal

We present a pulsed electrodeposition strategy for synthesizing mixed-phase 1 T/2H-MoS 2 quantum dots (QDs), yielding nanostructured films with remarkable catalytic performance. At an ultralow catalyst loading of 8 mg·L −1 , the MoS 2 QDs achieved 98 % degradation of methylene blue dye under solar simulator illumination, with a high reaction rate of 2 × 10 −2 min −1 . The QDs demonstrated strong visible-light activity and maintained 78 % efficiency after four consecutive cycles, confirming their long-term operational stability. The enhanced catalytic activity is attributed to the synergistic interplay of 1 T-MoS 2 and 2H-MoS 2 phases and the quantum confinement, which facilitates efficient charge separation and extends light absorption. Mechanistic insights highlight the key roles of reactive oxygen species and charge-transfer processes in the degradation pathway. These findings position electrodeposited mixed-phase 1 T/2H-MoS 2 QDs as promising, scalable photocatalysts for solar-driven wastewater remediation. • MoS 2 quantum dots (QDs) were synthesized using pulsed electrodeposition technique at ambient. • QDs achieved 98.4 % methylene blue degradation at 2 × 10 −2 min −1 rate and 8 mg/L catalyst loading. • Photodegradation performance improved with thinner films under solar-simulated light. • Degradation is driven by superoxide radicals ●O₂ − and holes as main reactive oxygen species.