Thermally-induced color transformation of hematite: insight …
2.2. Synthesis procedure. Figure 1 a exhibits the illustration of the synthesis procedure. First, Fe(NO 3) 3 ·6H 2 O solution (0.05 M) was heated at 80 °C, then added ammonia solution (NH 4 OH) dropwise while stirring thoroughly at the constant temperature. Next, the solution was stirred for 3 h and cooled down until room temperature. Figure 1 b …