Electrochemical and quantum chemical studies of peculiarities of 2,5-di-Me-pyrazine-di-N-oxide oxidation in the presence of methanol at single-walled and multi-walled carbon nanotube paper electrodes

Abstract

The use of methanol (MeOH) in direct methanol fuel cells explains the interest in the search for new electrode materials and catalysts that allow the oxidation of MeOH to be...

Effect of non‐covalent interactions in 2,5‐di‐Me‐pyrazine‐di‐N‐oxide ‐ methanol – Carbon nanotube electrocatalytic system

“…Dependences of the differential double layer capacitance C of MWCNT paper electrode on potential E of 0.1 M Bu 4 ClO 4 solution in MeCN in the presence of Pyr 1 [ 20 ] : 0 (curves 1,2) and 1 mM (curves 3–5), 1 mM Pyr 1 and 0.5 M MeOH (curve 6–8). Curves 1 and 2 were recorded just after recording cyclic voltammetry curves, curves 3, 4 and 5 are settled curves…”

“…Modeling the adsorption of MeOH, Pyr 1 , MeCN, Bu 4 NClO 4 and the complex of Pyr 1 *MeOH on the CNT surface using the ωB97XD functional was carried out within the cluster approximation. [ 18,20 ] According to previous calculations, [ 18 ] the most active sites are the grooves between two CNTs, but the tendencies persist during adsorption on single nanotube; therefore, in this work, adsorption on the surface of single nanotube is investigated.…”

“…In a previous work, [ 20 ] quantum‐chemical modeling and determination of the adsorption energy of the molecules of H 2 O and acetic acid (CH 3 COOH) on CNT electrodes and comparison with the adsorption energy of solvent molecules made it possible to explain the difference in the intensity of these effects on GC and CNT electrodes. The excess of the adsorption energy of CH 3 COOH compared to the adsorption energy of MeCN (solvent) on CNT electrodes causes a stronger manifestation of the inhibitory effect on CNT electrodes compared to the GC electrode (by 2.7 times).…”

“…In this work, quantum chemical modeling of non‐covalent interactions between the components of the electrocatalytic (Pyr 1 ‐ MeOH ‐ CNT) system in complexes MeCN*MeCN, MeOH*MeOH, MeOH*MeCN, Pyr 1 *Pyr 1 , Pyr 1 *Bu 4 NClO 4 , Pyr 1 *MeOH, Pyr 1 *MeCN in 0.1 M Bu 4 NClO 4 solution in MeCN and the calculation of adsorption energy of the components of catalytic system and complex of Pyr 1 *MeOH on the CNTs surface was performed. During the study, the methods of Raman spectroscopy and electrochemical data [ 18,20 ] were used. The data obtained will allow to establish new factors determining the features of mechanism of MeOH oxidation in the presence of 2,5‐di‐Me‐pyrazine‐di‐N‐oxide (Pyr 1 ) in 0.1 M Bu 4 NClO 4 solution in acetonitrile at SWCNT and MWСNT paper electrodes.…”

“…The adsorption energy of H 2 O on CNT electrodes is much lower than the adsorption energy of MeCN, and the catalytic effect of H 2 O is less pronounced than on the GC electrode. Thus, the use of quantum chemical modeling made it possible to explain the difference in the effects of CH 3 COOH and H 2 O on the catalytic process observed in [14][15][16][17]20] on CNTs electrodes compared to GC electrode. The existence of a dependence of the catalytic current on the presence of H 2 O or CH 3 COOH in the studied solutions confirms that the catalytic process, both on the GC electrode and on the CNT electrodes, proceeds with the elimination of protons.…”