Title : Conventional precipitation synthesis of Ca2Bi2O5 pure crystalline phase and its catalytic properties
Abstract:
The Ca-Bi-O materials have gained increasing interest within the scientific community due to their semiconductor and photocatalytic properties which were exploited for the degradation of different classes of substances such as antibiotics and organic dyes. The synthesis of these materials has been approached through the impregnation-calcination method, soft chemical method, flame spray method, sol-gel method, and others resulting in good photocatalytic properties in the visible range and high efficiencies for substances degradation. This work focuses on obtaining the Ca2Bi2O5 system by a simple, conventional method - precipitation with environmental application in dye degradation from water.
The material obtained was investigated by X-ray diffraction to identify the crystalline phase and complementary analysis with Raman spectroscopy. Fourier transform infrared spectroscopy, UV-VIS spectroscopy, and thermogravimetry completed the characterization of the obtained material, based on which the specific bands of the molecular bonds, mass loss, and diffuse reflectance were determined. The hybrid HSE06 functional was used in a first-principles calculation for this material to determine the energy band gap. The results highlighted a bandgap of 3.5 eV, similar to the bandgap obtained by diffuse reflectance recorded via UV-VIS spectroscopy on Ca2Bi2O5. To determine the catalyst efficiency for purification, the obtained material was tested for the degradation of the dye at different pH values of the solution and dye concentration. The influence of parameters was studied on the adsorption and photocatalytic stages. Based on the time-dependent absorbance for RhB solution, the RhB degradation efficiency was calculated to be greater than 50%.
Audience Takeaway:
- Novel and easy synthesis – coprecipitation – to obtain Ca2Bi2O5
- Characterization and identification of pure crystalline phase by Raman and XRD diffraction
- Analysis of RhB degradation as a response of Ca2Bi2O5 activation to light
- Different behavior of Ca2Bi2O5 activity depending on the parameters
Acknowledgement: This work was carried out through the Nucleu Program within the National Research Development and Innovation Plan 2022–2027, carried out with the support of MCID, project no PN 23 27 02 01, contract no. 29N/2023.
