Effect of Air Annealing on Structural, Textural, Thermal, Magnetic and Photocatalytic Properties of Ag-Doped Mesoporous Amorphous Crystalline Nanopowders Bi2O3

Abstract

Abstract Ag doped Bi2O3 nanopowders (NPs) were produced by pulsed electron beam evaporation (PEBE) under vacuum. The solid phase synthesis in an electric furnace on air was used for silver doping of bismuth oxide (addition of - 1 and 5 wt% crystalline silver nitrate). Structural, textural, thermal and magnetic properties of Ag doped Bi2O3 NPs have been studied. The specific surface area of (SSA) Ag- Bi2O3 NPs was 23.7 m2/g, which was almost 2 times bigger than the SSA of the pure Bi2O3 (13.2 m2/g). Air annealing (200 °C) caused decreased crystallinity and growth of SSA in all NPs, without exception. Silver doping reduced the grain size of NPs after they were air annealed compared to the grain size of NPs annealed pure bismuth oxide. The dominant phase in not annealed/annealed Ag doped Bi2O3 NPs at 200 °C and 300 °C was β -phase Bi2O3 with a tetragonal structure. Accordingly, the photocatalytic activity of the Ag doped NPs was higher in the doped Bi2O3. The thermal stability of the pure and Ag-doped Bi2O3 NPs was maintained at 300-350 °C. The phase transition β→α occurred with a further increase in temperature. The annealing temperature could effectively change the physicochemical properties of the Bi2O3 NPs.