Enhancement of NO₂ Gas Sensing Properties of Polypyrrole by Polarization Doping with DBS: Experimental and DFT Studies

Abstract

A new technique of polarization doping was adopted to improve NO2 gas sensing properties of the polypyrrole (PPy) sensor. PPy nanosheets polarization doped with sodium dodecyl benzenesulfonate (SDBS) were synthesized by low-temperature polymerization. The semiagglomerated PPy nanosheets were well-dispersed and a large specific surface areas due to the introduction of dodecyl benzenesulfonate (DBS). The DBS doped PPy sensor shows excellent NO2 sensing performance. Polarization of sulfonate ions to PPy enhanced the adsorption ability of NO2 with the synergistic effect of NO2. The adsorption energy (−0.676 eV) and electron transfer (0.521 |e|) of PPy to NO2 increased greatly after doping. An unoccupied electron state is observed in the valence band electron structure of PPy/DBS after the adsorption of NO2 by calculations of Density Functional Theory (DFT). The intermolecular synergy between NO2 and PPy/DBS causes a strong polarization, resulting in a high polarization potential, which enhances the NO2 sensing performance of PPy sensor. It is of great significance to develop NO2 detection device based on PPy that works at room temperature.

Enhancing the efficiency of polypyrrole-dodecylbenzene sulfonic acid in-tube solid-phase microextraction coating for analysis of nitrogen-containing pesticides in water environments

“…In particular, dodecylbenzene sulfonic acid (DBSA), as a surfactant, not only improves the thermal and mechanical stability of PPy upon doping but also provides additional adsorption sites through its sulfonic acid group, benzene ring, and long alkyl chain, thereby enhancing its adsorption capacity for polar nitrogen-containing pesticides. In the fields of sensors and electrocatalysis, PPy, with its conjugated double bond structure, can generate π-π interactions, dipole-dipole interactions, electrostatic interactions, and hydrophobic effects, making it an ideal adsorbent for polar and ionic compounds (Hussain et al, 2021;Du et al, 2023). However, pure PPy exhibits low thermal stability (thermal decomposition temperature of approximately 230 °C) and a small surface area, limiting its application in extraction performance (Ju et al, 2022;Wu et al, 2022).…”