Abstract:
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The polymer electrolyte membrane (PEM)-based electrolysis technology is a promising mean to
split water and store renewable energy in the form of clean fuel, hydrogen. However, its high
price due to the use of platinum group metals (PGMs) as catalyst materials generally makes the
technology cost-restrictive. Herein we present the performance evaluation of cobalt oxide in
PEM electrolysis as cathode catalyst where hydrogen evolution reaction (HER) takes place.
Performance comparison of non-PGM catalysts (CoO, Co3O4 and MoS2) revealed that better
performance was attained with Co3O4 and it was further improved by mixing with an electrically
conducting carbon material (Vulcan). An optimum amount of the carbon additive was found, and
the best performance was recorded at 47wt% Co3O4 over the total amount. At 2.05 V, 47wt%
Co3O4-based catalyst (0.55 A/cm2) outperformed 47wt% MoS2-based one (0.51 A/cm2). More
importantly, the performance of the former at 2.3 V (1.12 A/cm2) surpassed even that of Pt-black
(1.11 A/cm2). In situ XAS study of the Co3O4-based material under PEM electrolysis conditions
revealed dynamic interchange of Co3+ and Co2+ fractions, which was attributed to ultimately
boost the HER performance. |