Palladium-containing catalysts based on mesostructured material of the cmk type in the reaction of oxygen electroreduction

• Published in: Journal of applied electrochemistry 2023-04, Vol.53 (4), p.645-659
• Main Authors: Martynenko, Evgenia A., Vostrikov, Sergey V., Shafigulin, Roman V., Vinogradov, Kirill Yu, Tokranova, Elena O., Bulanova, Andzhela V., Zhu, Hong
• Format: Article
• Language: English
• Subjects: Catalysts; Chemical reduction; Chemical synthesis; Chemistry; Chemistry and Materials Science; Diffusion; Doping; Electrocatalysts; Electrochemistry; Electrodes; Electrolytes; Electrons; Electrowinning; Industrial Chemistry/Chemical Engineering; Ionic liquids; Ions; Low temperature; Nitrogen; Oxygen reduction reactions; Palladium; Physical Chemistry; Platinum; Polyanilines; Pyrolysis; Raman spectroscopy; Research Article; Rotating disks; Thermogravimetric analysis; X ray fluorescence analysis
• ISSN: 0021-891X; 1572-8838
• DOI: 10.1007/s10800-022-01808-5

Palladium-containing ordered mesoporous carbons, such as CMK-1 and CMK-3 doped with nitrogen by pyrolysis of polyaniline and modified with an imidazolium ionic liquid ([BMIM][Br]) have been synthesized. The carriers and electrocatalysts have been studied by low-temperature nitrogen adsorption, thermogravimetric analysis, X-ray fluorescence analysis, and Raman spectroscopy. A significant decrease in the surface of CMK materials was shown upon doping with nitrogen and modifying with an ionic liquid. Moreover, the electrocatalytic activity in the oxygen reduction reaction from an alkaline electrolyte has been studied by the potentiometric method using a three-electrode cell with a rotating disk as working electrode. In addition, the diffusion currents, half-wave potentials, initial potentials, and the number of electrons participating in the reaction are calculated. The values of the electrochemical active surface of the synthesized catalysts were determined on the basis of cyclic voltammograms. Modification CMK-3_Pd with ionic liquid made it possible to increase the diffusion current, which was not observed upon doping with nitrogen. Catalysts CMK-3_Pd and CMK-3_Pd_IL showed high efficiency in the reaction under study. The number of electrons transferred during the electroreduction of oxygen on these catalysts is about 3.5; mass activity in the diffusion region at a potential of −0.8 V is about 0.7 A/mgPd; and it is almost two times higher than that of the commercial platinum Pt/C catalyst. In the kinetic region at a potential of −0.05 V, the specific activity of the platinum catalyst is significantly higher than that of CMK-3_Pd and CMK-3_Pd_IL. Mass activity in the kinetic region for CMK-3_Pd and CMK-3_Pd_IL is comparable to the activity of the Pt/C platinum catalyst. It was shown that the activity of materials based on CMK in the reaction of oxygen electroreduction from an alkaline electrolyte will depend not only on the size of the electrochemically active surface of the catalysts, but also on the textural characteristics of these materials. Graphical abstract