alpha-Fe2O3 quantum dots: low-cost synthesis and photocatalytic oxygen evolution capabilities

Hematite (alpha-Fe2O3) quantum dots (QDs) with an average size of 3 nm are synthesized by a facile microwave-assisted reverse micelle method without any substrate and investigated for photocatalytic oxygen evolution for the first time. The QDs show very good crystallinity and a narrow size distribution. Homogeneous microwave heating and a fast nucleation process suppress the secondary growth stage of the particles, giving rise to their quantum size. Photocatalytic measurements reveal that the as-prepared alpha-Fe2O3 QDs show enhanced activity for visible-light-driven O-2 evolution in comparison to commercial alpha-Fe2O3. Temperature dependent XRD, XPS, and Mott-Schottky plots are carried out to better understand the role of surface states and high surface curvature on the QDs photocatalytic activities.