Protonation and deprotonation of polyaniline films and powders: effects of acid and base concentrations on the surface intrinsic oxidation states

Kang, E. T.; Li, Z.F.; Neoh, K. G.; Dong, Youming; Tan, K.L.

doi:10.1016/s0379-6779(98)80107-0

Cited by 16 publications

(8 citation statements)

References 33 publications

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“…As imine/amine ratio of emeraldine film can be affected by the base concentration [25], it is known that only upon exposure to a very strong base the emeraldine can become an insulator [15]. As the weak base was used in these experiments, authors believe this attributes to the amount of imine and amine in the polymer chains.…”

Section: Resultsmentioning

confidence: 99%

Hydrogen gas sensor based on highly ordered polyaniline nanofibers☆

Arsat

et al. 2009

Sensors and Actuators B: Chemical

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Section: Resultsmentioning

confidence: 99%

Hydrogen gas sensor based on highly ordered polyaniline nanofibers☆

Arsat

et al. 2009

Sensors and Actuators B: Chemical

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“…The strong interaction resulted in the proton transfer from the secondary amine hydrogen of pPy to the intermediate. Deprotonation/protonation of pPy in aqueous solutions was reported to be reversible. − The DFT calculation suggested that at least one of the oxygen surface intermediates preferred the secondary amine hydrogen of pPy over the proton/hydrogen sources of aqueous electrolytes. Energy barriers of the proton-accepting ORR steps were compared to determine which step allowed and favored the proton transfer from pPy rather than the electrolyte (Figure S10).…”

Section: Resultsmentioning

confidence: 99%

Breaking the Linear Scaling Relationship by a Proton Donor for Improving Electrocatalytic Oxygen Reduction Kinetics

et al. 2021

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Theoretical computational studies have claimed that the catalytic activity of a family of heterogeneous catalysts (e.g., metal catalysts) is governed by a linear scaling relationship (LSR) between adsorption energy levels of intermediates on active sites of catalysts. The volcano shape of the activity versus the adsorption energy of one of the intermediates was obtained from the LSR and the Brønsted–Evans–Polanyi relationship. An improved activity can be achieved using a catalyst having optimized adsorption energy of the volcano or alternatively by circumventing or breaking the LSR. Herein, we demonstrated that the LSR of a series of transition metal terephthalates (MTPs; M = Fe, Co, Ni, Cu, or Zn) as electrocatalysts for the oxygen reduction reaction (ORR) was broken in the presence of polypyrrole (pPy) as a proton donor. The reason for the LSR breakage was that the intermediate to which the proton of pPy was delivered was different depending on the metal of MTP. Also, pPy affected the adsorption energy of the specific intermediate (the target of the proton transfer) more strongly while the other intermediates were less affected by pPy. Experimentally as well as theoretically, pPy significantly improved the ORR activity of MTPs, altering the activity volcano plot. The most significant improvement was found on CoTP: the onset potential of ORR on CoTP was shifted toward the more easy-to-be-reduced direction from 0.7 to 0.85 VRHE at 1 mA cm–2.

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“…A further variable relevant to the composition of PANI materials is the degree of oxidation (or oxidative doping level) and this can be determined by XPS by examining the oxidation states of N present, via the N 1s [28] signal. N 1s XPS for H-PANI and DB-PANI are shown in Fig.…”

Section: X-ray Photoelectron Spectroscopymentioning

confidence: 99%