Anion exchange membrane water electrolyzer with an ultra-low loading of Pt-decorated Ni electrocatalyst

•Pt-decorated Ni electrocatalysts were prepared on carbon paper (Pt-Ni/CP).•Pt-Ni/CP electrode contained 650 nm Ni particles encapsulated by 50 nm Pt dots.•Ultra-low amount catalyst of 1.85 μgPt/cm2 was loaded in Pt-Ni/CP electrode.•A MEA employing Pt-Ni/CP electrode showed a current density of 250 mA/cm2 at 1.9 V.

The particle-type electrodes with ultra-low electrocatalyst loading (<10 μg cm−2) were developed as cathodes in the anion exchange membrane water electrolyzer (AEMWE). The Pt-decorated Ni electrocatalysts were prepared on the surface of carbon paper by Ni electrodeposition and subsequent displacement of Ni by Pt; the composition and morphology were controlled by varying HCl concentration. In half cell test, the increase of hydrogen evolution reaction (HER) activity by Pt decoration was confirmed for Pt-Ni/CP-2 that has Pt ratio of 39.4% (1.85 μgPt cm−2). A membrane electrode assembly employing Pt-Ni/CP-2 as the HER electrode (total catalyst loading: 13.2 μg cm−2) exhibited a current density of 250 mA cm−2 at 1.9 Vcell (50 °C), which is comparable to the previous reports with much larger loading of 3.1 ∼ 80 mg cm−2.

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