Enhancement of NO 2 Gas Sensing Properties of Polypyrrole by Polarization Doping with DBS: Experimental and DFT Studies.

A new technique of polarization doping was adopted to improve NO 2 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 NO 2 sensing performance. Polarization of sulfonate ions to PPy enhanced the adsorption ability of NO 2 with the synergistic effect of NO 2 . The adsorption energy (-0.676 eV) and electron transfer (0.521 |e|) of PPy to NO 2 increased greatly after doping. An unoccupied electron state is observed in the valence band electron structure of PPy/DBS after the adsorption of NO 2 by calculations of Density Functional Theory (DFT). The intermolecular synergy between NO 2 and PPy/DBS causes a strong polarization, resulting in a high polarization potential, which enhances the NO 2 sensing performance of PPy sensor. It is of great significance to develop NO 2 detection device based on PPy that works at room temperature.