Effects of calcination temperature on preparation and properties of europium-doped bismuth oxide as visible light catalyst

Abstract

Eu-doped bismuth oxide (Bi2O3) (optimal Eu doping ratio 1:4) was prepared via sol–gel method, and then used to carry out the precursors for 5 h calcinations at 300, 400, 500, and 600 °C separately. The as-synthesized materials were characterized using X-ray diffraction, scanning electron microscope, Brunauer–Emmett–Teller analysis, X-ray photoelectron spectroscopy, diffuse reflectance ultraviolet–visible spectroscopy and surface photovoltage spectroscopy. The results showed that the calcination temperature observably affected the photocatalytic activity, and specifically, temperature rise was favorable for crystallization of the photocatalyst. The smallest forbidden bandwidth was found in catalyst-400 (about 2.75 eV). The strongest photovoltage signal was within 550 nm. It meant the optimal calcination temperature was 400 °C. The phenol degradation efficiency of Eu-doped Bi2O3 samples were tested under visible light strength 1.8 × 105 Lux(xenon lamp), the results showed that in catalyst-400, the maximum degradation efficiency was 91.07 % with the highest photocatalytic activity.