Multicomponent nonprecious hydrogen evolution catalysts for high performance and durable proton exchange membrane water electrolyzer

Abstract The commercialization of proton exchange membrane water electrolysis (PEMWE) as an environmentally friendly energy storage technology requires the development of highly active non-Pt catalysts that are stable in acidic media. Nonprecious CuNiMo ternary catalysts with superior activity and durability for the hydrogen evolution are electrodeposited. A wide range of compositions, from Cu and Ni as single metals to binary and ternary alloys, are tested to identify the composition range in which the intrinsic activity is enhanced. In particular, Cu44.4Ni46Mo9.6 exhibits superior electrochemical characteristics, comparable to those of Pt group metals, with a Tafel slope of 27.7 mV dec−1 and an overpotential of 18 mV at −10 mA cm−2. Moreover, during a long-term durability test (24 h at −10 mA cm−2), the overpotential only decays by a few millivolts owing to the modified electronic structure obtained by alloying. PEMWE with Cu44.4Ni46Mo9.6 cathode exhibits 266% higher activity than the average activity of recently reported non-Pt cathode-based PEMWEs at 1.9 Vcell without degradation of performance during 48 h operation. Thus, Cu44.4Ni46Mo9.6 is a promising catalyst for the cost-efficient PEMWE.