Controllable synthesis and photocatalytic activity of ultrathin hematite nanosheets

Ultrathin hematite (α-Fe2O3) nanosheets with highly exposed (110) facets were prepared via hydrothermal synthesis by controlling the concentration of silicate anions and pH. With the increase in silicate anions and decrease in pH, the growth of the c-axis for α-Fe2O3 was inhibited, whereas the growth of the a-axis was facilitated, leading to the formation of ultrathin α-Fe2O3 nanosheets. The as-prepared ultrathin α-Fe2O3 nanosheets exhibited expanded surface area and increased exposed (110) facets, which can effectively adsorb the visible light and inhibit the recombination of the electron and hole pairs, leading to superior photocatalytic activity toward the degradation of p-NP. A possible mechanism was also suggested for the p-NP degradation.