A Step Forward: Hydrogen Production on Cobalt Molybdenum Sulfide Electrocatalyst in Anion Exchange Membrane Water Electrolyzer

Abstract

Cobalt molybdenum sulfide (Co0.5Mo0.5S x ) was evaluated, as an alternative cathode catalyst for hydrogen large scale production in an anion exchange membrane water electrolyzer (AEMWE). Performance testing in a Co0.5Mo0.5S x //Ir single cell fed with 0.1 mol L–1 KOH exhibited the best activity reported to date for transition metal sulfide cathodes in alkaline media. The aforementioned cell presented good stability during 40 h of operation at 2 V; in addition, it has most of its current density degradation recovered in the beginning of the subsequent 10 h interval.

Key components and design strategy of the membrane electrode assembly for alkaline water electrolysis

“…The morphology, composition and performance of self-supported electrodes can be effectively regulated via the electrodeposition solution (by varying the composition, pH, and temperature) and electrochemical operation (by varying time, current and potential). 289 Most transition-metal-based materials such as oxides, 216 hydroxides, 287 sulfides, 223 selenides, phosphides, 76 and alloys 290 can be electrodeposited on a conducting LGDL. Ahn et al developed a MEA by potentiostatic deposition of nickel on CP for alkaline water electrolysis.…”

“…(c): 1,26 2,180 3,204 4,93 5,205 6,54 7,206 8,86 9,207 10,183 11,74 12,29 13,208 14,181 15,184 16,185 17,186 18,187 19,209 20,36 21,94 22,210 23,188 24,211 25,190 26,191 27 212. (d): 1,26 2,59 3,213 4,214 5,215 6,216 7,217 8,218 9,219 10,147 11,220 12,221 13,222 14,223 15,29 16,67 17,185 18,94 19,224 20,210 21,225 22,226 23,227 24,228 ...…”

HER activity of nickel molybdenum sulfide electrocatalyst as function of the ionomer in the ink formulation

“…While many catalysts produced from earth-abundant elements are not stable in acidic environment, many researchers have been devoting their attention to the development of water electrolysis in alkaline media [6][7][8][9]. However, the hydrogen evolution in high pH's has some drawbacks as the additional energy-consuming step called water dissociation, besides the interaction of generated hydroxyl groups with active sites that can play a negative role in the reaction [7,8,10].…”

“…Many articles show the evaluation and comparison of different membranes [15][16][17] and catalysts [4,5,9,18] performances as main topic, however, lower attention has been addressed to the ionomer or even the interaction between the ionomer and the catalyst [14], although there are manuscripts that report its impact on catalysts activity [19][20][21]. Nafion® is the unanimous ionomer for applications in acidic media and, although it has its efficiency decreased in alkaline conditions [4], it is still widely used in analysis at high pH's [10,22,23].…”