Integrating third phase transition and CO/CO2 contamination in microwave tailored Bi2Mo1−xWxO6 nano materials

Abstract

First layer Aurivillius Bismuth Molybdate Tungstate ceramic [Bi2Mo1−xWxO6 (BMoW); x = 0.00, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.08 and 0.10] compositions are prepared using deep penetrating microwave sintering in air. All samples show known perovskite phase formation just after 5 h calcinations at 575 °C. X-ray diffraction and transmission electron microscopy based energy dispersive spectroscopy are used to confirm the phase-purity and gross elemental concentration change besides particle size. Nearly double $$\varepsilon ^{\prime}$$ -values are obtained for investigated BMoW materials compared to earlier reported values. Silver percolation through electrodes in bismuth oxide deficient surfaces of BMoW ceramic powders induces radio wave absorption in the frequency range 2 to 4 MHz. Characteristic third phase transition ( $$\gamma \to \gamma ^{\prime\prime\prime}$$ ) of Bi2MoO6 material dissolves gradually on increasing tungsten concentration. The introduction of tungsten in BMo matrix increases the dipolar strength of MoO6 octahedrons bending against infrared absorption as evidenced from FTIR analysis. Additionally appearing FTIR peaks provide a strong indication of CO and CO2 contamination on exposed powder surfaces useful for photocatalytic applications.