Electrocatalytic hydrogen production using the designed hexaphenanthrene iron, cobalt and ruthenium(II) cage complexes as cathode (pre) catalysts immobilized on carbonaceous substrates

Hexaphenanthrene iron, cobalt and ruthenium(II) macrobicyclic complexes, the molecules of which have been designed for their efficient immobilization on carbon materials, such as activated carbon (AC), reduced graphene oxide (RGO) and carbon paper (CP), were tested as the cathode electro(pre)catalysts for hydrogen production in a PEM MEA water electrolysis cell. They were found to possess the good performances of hydrogen production. The use of the suitable carbon materials of a high surface area, AC and RGO, as the substrates for their efficient immobilization, as well as the addition of Nafion (R) as a polymer electrolyte, allowed to substantially increase an electrocatalytic activity of the corresponding clathrochelate-containing CP-based cathodes. Chemical design of the above metal-encapsulating cage molecules allowed a substantial decrease in a consumption of these metals by using their adsorbed monolayers. The high adsorptive capacities of the suitable carbon materials resulted in a substantial increase in a surface concentration of their electrocatalytically active centers, and, therefore, in that of an electrocatalytic activity of the obtained hybrid clathrochelate-containing carbon-based cathode materials. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.