Polyaniline Functionalization of Defective 1T-MoS2 Nanosheets for Improved Electron and Mass Transfer: Implications for Electrochemical Sensors

• Published in: ACS applied nano materials Vol. 6; no. 13; pp. 11725 - 11736
• Main Authors: Gan, Xiaorong, Zhang, Jianlin, Liu, Jiabei, Bai, Yuanhe, Su, Xinyi, Wang, Weiqing, Cao, Zhuang, Zhao, Huimin, Ao, Yanhui, Wang, Peifang
• Format: Journal Article
• Language: English
• Published: American Chemical Society 14-07-2023
• Subjects: two-dimensional nanomaterials; electrochemical sensors; heavy metal ions; conductive polymers; electroactivity; density functional theory (DFT); analytical chemistry
• ISSN: 2574-0970; 2574-0970
• DOI: 10.1021/acsanm.3c01679

Simultaneously improving electron and mass transfer processes is full of challenges for electrode material design. To this end, three-dimensional (3D) porous electrode materials were obtained via covalent combination between defective 1T-MoS2 nanosheets and polyaniline (PANI) through hydrothermal/solvothermal processes and surface polymerization reactions. Our experimental results and density functional theory calculations jointly reveal that PANI molecules can not only intercalate into van der Waals (vdW) gaps of 1T-MoS2 nanosheets but also chemically adsorb onto S-vacancy clusters (via Mo–N covalent bonds), rather than single atomic S-vacancies due to steric effects. Similarly, the geometric structure of PANI in the vdW gaps of 1T-MoS2 nanosheets possesses a flat-lying configuration for better stability. Compared to surface functionalization, interlayer intercalation has more profound effects on electronic structures for improving electrochemical properties, including reduced band gaps, small effective electron masses, and high mobility. As a proof-of-concept application, the 1T-MoS2–PANI nanocomposites were used to construct an electrochemical sensor for trace Cu2+, which exhibits high sensitivity and selectivity with a wide linear range from 3 to 450 nM and a low detection limit because of excellent conductivity, a low contact barrier against electron transfer, high mass transfer, and strong coordination interactions between PANI and Cu2+.