DFT Study of Polyaniline NH3, CO2, and CO Gas Sensors: Comparison with Recent Experimental Data

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• 作者：Habib Ullah ; Anwar-ul-Haq Ali Shah ; Salma Bilal ; Khurshid Ayub
• 刊名：Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：November 14, 2013
• 年：2013
• 卷：117
• 期：45
• 页码：23701-23711
• 全文大小：517K
• 年卷期：v.117,no.45(November 14, 2013)
• ISSN：1932-7455

文摘

Density functional theory studies (DFT) have been carried out to evaluate the ability of polyaniline emeraldine salt (PANI ES) from 2 to 8 phenyl rings as sensor for NH₃, CO₂, and CO. The sensitivity and selectivity of nPANI ES among NH₃, CO₂, and CO are studied at UB3LYP/6-31G(d) level of theory. Interaction of nPANI ES with CO is studied from both O (CO(1)) and C (CO(2)) sides of CO. Interaction energy, NBO, and Mulliken charge analysis were used to evaluate the sensing ability of PANI ES for different analytes. Interaction energies are calculated and corrected for BSSE. Large forces of attraction in nPANI ES-NH₃ complexes are observed compared to nPANI ES鈥揅O₂, nPANI ES-CO(1), and nPANI ES-CO(2) complexes. The inertness of ⁺C鈮^{鈥?/sup> in nPANI ES-CO(1) and nPANI ES-CO(2) complexes are also discussed. Frontier molecular orbitals and energies indicate that NH₃ changes the orbital energy of nPANI ES to a greater extent compared to CO₂, CO(1), and CO(2). Peaks in UV鈥搗is and UV鈥搗is鈥搉ear-IR spectra of nPANI ES are blue-shifted upon doping with NH₃, CO₂, CO(1), and CO(2) which illustrates dedoping of PANI ES to PANI emeraldine base (PANI EB). Finally, it is concluded that PANI ES has greater response selectivity toward NH₃ compared to CO₂ and CO and it is consistent with the experimental observations.}