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Facile electrochemical preparation of nonprecious Co‐Cu alloy catalysts for hydrogen production in proton exchange membrane water electrolysis
Author(s) -
Kim Hoyoung,
Park Hyanjoo,
Oh Seonhwa,
Kim SooKil
Publication year - 2019
Publication title -
international journal of energy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.808
H-Index - 95
eISSN - 1099-114X
pISSN - 0363-907X
DOI - 10.1002/er.5099
Subject(s) - overpotential , catalysis , proton exchange membrane fuel cell , materials science , electrochemistry , exchange current density , alloy , hydrogen production , chemical engineering , electrolysis , electrolysis of water , electrocatalyst , transition metal , inorganic chemistry , metallurgy , tafel equation , chemistry , electrode , electrolyte , engineering , biochemistry
Summary To realize nonprecious‐metal catalysts with practical applicability for the hydrogen evolution reaction (HER), improved corrosion resistance and catalytic activity are required. In this study, composition‐controlled Co‐Cu alloys were fabricated by electrodeposition for use as HER catalysts in proton exchange membrane water electrolyzers (PEMWEs). As the Cu content in the alloy increased, the morphology changed from needle‐shaped particles to small round particles. Furthermore, a phase transition from a hexagonal close‐packed structure to a face‐centered cubic structure occurs because the latter structure is stabilized by adding Cu to Co. The optimum catalyst composition for the HER was found to be Co 59 Cu 41 , which had an overpotential of 342 mV at −10 mA cm −2 . This catalyst exhibited excellent durability, showing a potential reduction of approximately 100 mV over 12 hours under a constant current density. This superior performance was attributed to the increase in the electrochemical surface area resulting from the addition of Cu, as confirmed by electrochemical double layer capacitance measurements, in addition to a counterbalance between the hydrogen adsorption energies of Co and Cu. Finally, the application of the Co‐Cu alloy catalyst as a cathode catalyst in a PEMWE resulted in excellent performance of 1.2 A cm −2 at 2.0 V cell .