Pyrocatalysis-driven dye degradation by Zn Doped NBT-BT: A comparative analysis between powder and bulk

Abstract

The present work investigates pyrocatalytic degradation of methylene blue (MB) dye in water using 0.94Na1/2Bi1/2TiO3-0.06BaTiO3 (NBT-6BT). The poled NBT-6BT degraded MB dye 7 % more (81 %) than the unpoled NBT-6BT (74 %). The degradation is enhanced by doping ZnO in NBT-6BT-xZnO (where x = 0.005, 0.01 and 0.02) from 81.5 % to 87 % with increasing Zn doping from 0.5 mol % to 2 mol %, respectively. The dye concentration and powder amount is varied to understand the effect on dye degradation. Scavengers test and fluorescence experiment ensured the presence of ·OH radical in the pyrocatalysis process. The repeatability test is performed to analyze the feasibility of 0.94Na1/2Bi1/2TiO3-0.06BaTiO3-0.02ZnO (NBT-6BT-0.02ZnO) for practical application. The limitation of powder for pyrocatalysis is overcome by studying the poled bulk pellets of NBT-6BT and NBT-6BT-0.02ZnO. The quantity of MB dyes (2.5–15 mL) and pellet surface area (30–240 mm2) with a fixed dye concentration of 5 mg L−1 are varied to understand the effect on pyrocatalytic degradation. It was found that with increasing pellet surface area, degradation increases.