Hydrogen electrochemical sorption-desorption by multiwall carbon nanotubes (MWCNT) obtained by the catalytic pyrolysis method has been investigated. It has been shown that during cathode process execution hydrogen is adsorbed at the electrode surface in the amount corresponding to approximately one monolayer.
Using potentiodynamic and galvanostatic cycling methods the main technological parameters have been estimated which may affect the amount of hydrogen adsorbed by MWCNT and to increase the efficiency of its reversible sorption-desorption process. These parameters are: method of the nanotubes pretreatment, value of specific surface area, previous ultrasonic dispersion, the presence of catalytic centers, their nature and obtaining method, as well as the methods of preparation electrode masses and electrodes in whole. Besides above technological parameters, the processes of the hydrogen electrochemical sorption-desorption depend on the electrolyte composition, previous electrochemical activation, and electrode layer thickness.
The presence of catalytic centers formed of palladium and platinum leads to increasing of the MWCNT specific capacity and to enhancement of the electrochemical cycling. Besides high-cost metals, to form catalytic centers at the MWCNT surface one may use multinuclear bimetallic complexes of 2Сo-Ni compounds with monoethanolamine, deposition of which onto MWCNT surface has advantages over diethanolamine and triethanolamine ones.
Keywords: nanotubes, modification of the surface, electrochemical hydrogen storage