Mn/O co-doped Bi2S3 bimetal oxysulfide catalyst for highly efficient reduction of organic and hexavalent chromium pollutants in the dark

• Published in: Materials today chemistry 2023-10, Vol.33, p.101697, Article 101697
• Main Authors: Wu, Binghong, Su, Zhengjie, Wu, Qinhan, Kuo, Dong-Hau, Zhang, Pengkun, Chen, Longyan, Abdeta, Adugna Boke, Mosisa, Mengistu Tadesse, Lin, Jinguo, Chen, Xiaoyun, Liu, Xueshen
• Format: Article
• Language: English
• Subjects: Bi2S3 phase; Bimetal oxysulfide; Mn/O co-doping; Organic reduction; Under the dark
• ISSN: 2468-5194; 2468-5194
• DOI: 10.1016/j.mtchem.2023.101697

Mn and O co-doped Bi2S3 (labeled as BiMnOS) catalyst was synthesized using different amounts of Mn precursor (MnCl2.4H2O) by a simple and feasible method and characterized by various techniques. The doped Mn and O improve the energy band structure and morphology, reduce the charge transfer resistance, increase the electrochemically active surface sites, and the heterovalent Mn3+/Mn2+ states in Mn/O–Bi2S3 enhances the electron lifetime and facilitates fast electron transfer, which accelerates the pollutants reduction reaction. The BiMnOS-3 at n(Mn): n(Bi): n(C2H5NS) = 4: 1: 4 has the best-reducing properties. 10 mg BiMnOS-3 ultimately reduced the 20 ppm 100 mL 4-aminophenol (4-NP) solution in the presence of NaBH4 within 14 min, and the reduction rate constant of 0.3514 min−1 was 12.5 times that of BiOS and 11.7 times that of MnOS. The reduction reactions of methyl orange (MO), methylene blue (MB), Rhodamine B (RhB), and Cr (VI) were also completed within 8, 10, 28, and 24 min, respectively. The catalytic activity of BiMnOS-3 remained above 90.6% after 6 repeated tests for the reduction of 4-NP, which showed good cycling stability. Therefore, this study verified that the suitable ratio of the metal precursors plays a vital role in designing novel, efficient, and synergistically defect-attired bimetal oxysulfide catalysts. •Mn/O co-doped Bi2S3 bimetal oxysulfide catalyst was prepared by a facile method.•The Mn3+/Mn2+ in BiMnOS affected its electron transport and catalytic activity.•BiMnOS catalyst exhibited fast reduction of organic pollutants and heavy metal ions.•Kinetic mechanism is proposed to explain the fast reduction of pollutant in the dark.