Synthesis, structure, and characterization of RbNdGe2O6 as a novel visible-light-driven catalyst for photodegradation methylene blue

• Published in: Journal of solid state chemistry 2020-05, Vol.285, p.121246, Article 121246
• Main Authors: Zhang, Jian-Han, Hao, Xian-Dong, Wang, Xin, Su, Zhi-Zhong, Luo, Ju-Xiang, Wu, Hong-Yan, Lin, Fu-Xing
• Format: Article
• Language: English
• Subjects: High-temperature solid-state reaction; Lanthanide germanate; Methylene blue; Photodegradation; Visible-light-driven
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2020.121246

A novel lanthanide germanate, namely RbNdGe2O6, has been successfully synthesized by high-temperature solid-state reaction in open air atmosphere for the first time. Single crystal X-ray diffraction indicates a 3D framework composed of 1D neodymium oxygen chains connected with cyclogermanate Ge3O9 units with Rb+ located in the internal space. X-ray powder diffraction coupled with Rietveld refinement reveals the sample’s phase purity we have prepared. Thermal behavior analysis shows RbNdGe2O6 is very stable, it doesn’t decomposition until heated up to 998 ​°C. UV–visible absorption and diffuse reflection spectrum feature characteristic absorption bands of f-electron transition and an optical bandgap value of 4.65 ​eV. Magnetic susceptibilities measurement gives significant antiferromagnetic interactions between magnetic centers. The photodegradation experiments were performed to evaluate photocatalytic activities of RbNdGe2O6. By using P25 as a reference, RbNdGe2O6 features to be an effective visible-light-driven catalyst in photodegrading methylene blue. Although the BET value of RbNdGe2O6 is only 3% that of P25, the photocatalytic activity reaches 0.55 times that of P25. Furthermore, the proposed photocatalytic mechanism which dominated by holes was further verified by adding ammonium oxalate as a quencher. New compound RbNdGe2O6 was reported for the first time. Its structure features a 3D framework composed of 1D neodymium oxygen chains connected with cyclogermanate Ge3O9 units with Rb+ located in the internal space. This material features an impressive visible-light-driven photodegradation methylene blue, and the proposed photocatalytic mechanism was also studied. [Display omitted]