Synthesis and characterization of micro-/nano-α-Fe 2 O 3 for photocatalytic dye degradation.

Photocatalytic activity using micro-/nano-α-Fe 2 O 3 on a large scale was carried out using a sol-gel autocombustion method. A degradation time of 60 min was noted for 50 mg of the catalyst. Post characterization, this catalyst system showed a degradation of about 53% (rate = 2.60 × 10 -3 min -1 ) and 17% (rate = 1.38 × 10 -2 min -1 ) under sunlight and up to 45% (rate = 1.13 × 10 -3 min -1 ) and 7% (rate = 1.20 × 10 -2 min -1 ) under a 400 W UV lamp for rhodamine 6G (R6G) and crystal violet (CV), respectively. Sunlight has a broad spectrum of light; it greatly accelerates the degradation process and creates ideal conditions for the reaction to occur. The rate of photocatalytic dye degradation of α-Fe 2 O 3 without Fenton's reagent was found to be 7.84 × 10 -3 min -1 in the presence of external air provided (in the photocatalytic setup) through a bubbler and 3.23 × 10 -3 min -1 in the absence of the bubbler.