Ultrathin sillenite nanosheets with wide-spectrum response and high photocatalytic oxidation performance

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2024-02, Vol.12 (7), p.4268-4277
• Main Authors: Sun, Hao, Wang, Chen, Zhang, Yaning, Shao, Yunhang, Bian, Gaoming, Wang, Zhenlin, Chen, Chaofeng, Liu, Hongyan, Dou, Shuai, Xu, Jing, Zhang, Ying, Lou, Yang, Zhu, Yongfa, Pan, Chengsi
• Format: Article
• Language: English
• Subjects: Absorption; Bilayers; Bismuth trioxide; Catalysts; Catalytic activity; Ciprofloxacin; Electrostatic properties; Evolution; Nanoparticles; Nanosheets; Oxidation; Oxygen; Phase transitions; Photocatalysis; Photooxidation; Titanium dioxide
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d3ta06783a

Herein, we present a novel approach to synthesize ultrathin sillenite nanosheets (Bi 12 (MO 4 ) x O 16 , M = Bi 3+ , Si 4+ , Mn 4+ , Ti 4+ , and (Bi V 0.5 Fe III 0.5 ) 4+ ) by employing a phase-switched oriented attachment method in the presence of [CrO 2 ] − . [CrO 2 ] − and its hydrolyzed counterpart, CrOOH, are demonstrated to have a strong electrostatic interaction with the Bi-layer of an α-Bi 2 O 3 -phased precursor, inducing the formation of Cr-species coated α-Bi 2 O 3 nanosheets. The subsequent phase transition from α-Bi 2 O 3 to sillenite is found to weaken the interaction and release the Cr species, resulting in the formation of uncoated sillenite nanosheets. The nanosheets are ca. 1.5 nm thick and exhibit broad solar spectrum absorption above 600 nm. The photocatalytic activity on γ-Bi 2 O 3 sillenite nanosheets is investigated by degrading ciprofloxacin pollutants. Remarkably, we observe a 16 times enhancement in photocatalytic performance compared to the particles and a 4.6-fold improvement over the well-known P25-TiO 2 catalyst. This enhancement is attributed to the sillenite nanosheet structure facilitating photogenerated charge separation and, consequently, boosting photocatalytic activity. In addition, it was found that γ-Bi 2 O 3 nanosheets exhibited photocatalytic oxygen evolution performance, while γ-Bi 2 O 3 nanoparticles did not exhibit oxygen evolution activity. Our discovery of these wide-spectrum-absorption sillenite nanosheets presents a promising avenue for the development of highly efficient photocatalysts, poised to harness sunlight for various applications in the future. γ-Bi 2 O 3 nanosheets effectively promote charge separation and enhance antibiotic degradation and oxygen evolution activity.