Degradation of molybdenum disulfide through cascade reactions with hydrogen peroxide in aqueous system

• Published in: Journal of hazardous materials 2024-12, Vol.484, p.136794, Article 136794
• Main Authors: Xu, Dongfang, Yao, Jinhao, Chi, Yuantong, Liu, Zhuomiao, Lan, Ruyi, Wang, Meng, Su, Wenli, Liu, Xia, Dai, Yanhui, Yue, Tongtao, Zhao, Jian
• Format: Article
• Language: English
• Subjects: Degradation mechanism; Environmental fate; Fenton reaction; MoS2; Superoxide radical
• ISSN: 0304-3894; 1873-3336; 1873-3336
• DOI: 10.1016/j.jhazmat.2024.136794

Transformation is a crucial process determining the lifespan and risk of MoS2 nanomaterial during usage and after disposal. This study revealed the degradation of MoS2 in the presence of H2O2 using experimental and computational methods. Experimental results showed that MoS2 nanosheets were degraded by 45.1 % after 72-h incubation with H2O2. MoS2 decomposed H2O2 into various reactive oxygen species, among which ·O2- played a dominant role breaking MoS2 into fragments with defects and holes. Mo (IV) in MoS2 catalyzed ·O2- formation through electron transfer towards H2O2. Additionally, electrons generated from cleavage of O-O in H2O2 initiated the O2 reduction to generate ·O2-. The interaction of MoS2 with ·O2- yielded soluble MoO42– and SO42–, and 22.4 % of Mo on residual MoS2 was in the form of Mo (VI) after 72-h incubation. Density function theory calculations elucidated that·O2- is more potent than ·OH in adsorbing on MoS2 ( −2.25 eV vs. −0.14 eV) to initiate reaction. The reaction occurred preferentially from Mo and adjacent S atoms, which transferred 1.07 electrons toward ·O2- to induce O-O cleavage and formation of O-M and O-S bonds. The obtained finding on MoS2 degradation is fundamental for promoting sustainable applications and risk assessment of MoS2-based nanomaterials. [Display omitted] •MoS2 nanosheet underwent degradation in H2O2-containing aqueous system.•MoS2 was degraded by secondary ROS, and ·O2- rather than ·OH played important role.•Experiments and simulated calculation results confirmed the more stable absorption of MoS2 with O2- than ·OH.•The byproducts (MoO42-, SO42-, O2, H+) were identified during MoS2-H2O2 interaction.