The cobalt(II) cage complexes with terminal mercapto groups were immobilized on a surface of the working gold electrode. The clathrochelate-modified electrodes demonstrate a high electrocatalytic activity for a long time without loss of catalytic activity in range of pH from 1 to 7 and chemical stability of and an absence of the desorption or decomposition of the immobilized cobalt cage complexes. The controlled-potential electrolysis with gas chromatography analysis confirmed the production of H-2 in the high Faraday yields. In aqueous solutions, the sulfide pendants with activated alpha-hydrogen atoms in the second coordination sphere of this encapsulated metallocenter may undergo a fast deprotonation -reprotonation reaction, which leads to increased rate formation of the H-H bond. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.