Electrodeposited Co-Fe and Co-Fe-C Alloys for Hydrogen Evolution in a Hot 8 kmol m<SUP>-3</SUP> NaOH Solution

Abstract

Tailoring of active cobalt alloy cathodes for hydrogen evolution in a hot concentrated sodium hydroxide solution was attempted by electrodeposition. Enhancement of cathodic activity of cobalt for electrolytic hydrogen evolution has been carried out by the formation of Co-Fe and Co-Fe-C alloys containing different content of iron. The carbon addition to Co-Fe alloys was made to enhance the electrolytic hydrogen evolution activity and to prevent open circuit corrosion in 8 kmol m À3 NaOH at 363 K. The best condition for electrodeposition of Co-Fe alloy was pH 4 and the iron sulfate concentration of more than 5 kg m À3 . Under this condition the alloy was obtained with nanocrystalline bcc phase as a dominant and with the highest hydrogen evolution activity. The carbon addition slowed down preferential iron dissolution by open circuit corrosion in the hot alkaline solution but was not effective in complete prevention of the open circuit corrosion and in enhancing the hydrogen evolution.

Enabling Silicon for Solar-Fuel Production

“…As a third component, carbon is also widely used in alloy HER metal catalysts to enhance the charge transfer between metal ions. For example, carbon has been introduced to NiFe, CoFe, and NiCoFe alloys. In these works, the effects of added carbon on the activity and durability have been investigated.…”

Electrochemistry at Krakowian research institutions

“…The superhydrophobic properties of coatings are also in interest of scientists [43]. Research groups have been collaborating with international groups from Germany [44][45][46][47], Japan [48][49][50][51][52], France [53], Algeria [54] [87][88][89][90][91] is also an important issue for scientists. The topic of SOFC [92] is explored as well.…”

Intrinsic Catalytic Activity for the Alkaline Hydrogen Evolution of Layer-Expanded MoS2 Functionalized with Nanoscale Ni and Co Sulfides

“…The activity of Fe-based nanoparticles immobilized on N-doped carbon is less impressive, with the HER current density of 10 mA cm –2 (35 A g –1 ) requiring an overpotential of at least 0.33 V . Another way to improve the activities of Co and Fe for the HER is by alloying with each other and Ni or Cu. − According to theory, such combinations might provide a Gibbs free energy of the hydrogen and OH adsorption close to optimal values affording better activity. − Among multimetallic systems, classical HER molybdenum-containing alloy catalysts such as NiCoMo, NiMo, − NiMoCu are well-known for their high performance. Mixed hydroxides of the aforementioned metals, in particular NiCoMo and NiCoFe combinations, have also recently come into focus as catalysts for the alkaline HER with respectable activity …”