Multi-metal layer deposited carbon paper electrodes explored for stability enhancement of PEM water electrolysis

Proton exchange membrane water electrolysis (PEMWE) is a promising device for producing hydrogen due to its outstanding advantages. However, its strong acidic environment is still remaining problem. To overcome the issue, noble metals such as titanium porous transport layer (PTL) are mainly used. However, they have still problems in cost and scale up. To alleviate the issues, this study suggests multiple metal layer (MML) coated carbon as both PTL and electrode. With adoption of this MML consisting of nickel, gold and iridium (Ir), carbon durability is improved and noble metal usage is reduced. Additionally, the new MML coated carbon adopted in anode promotes excellent oxygen evolution reaction (OER) activity of 68.3 ± 4.8 mA cm⁻² at 1.7 V vs. RHE. This is because Ir deposited on outer surface of MML coated carbon is used as catalyst increasing OER activity. When PEMWEs including this MML coated carbon are operated, they are stably operated for 460 h at 100 mA cm⁻², while their degradation rate is very low as 0.194 mV/h over 100 h under 40mA cm⁻². This is because a new MML coated carbon provides more active sites for OER and better resistance of carbon corrosion. With the benefits, performance and stability of PEMWEs including this MML coated carbon are improved, reducing the amount of noble metal consumed and relieving economic drawback of conventional PEMWEs.