Suppressing Mo‐Species Leaching in MoO <sub>x</sub> /A‐Ni <sub>3</sub> S <sub>2</sub> Cathode for Stable Anion Exchange Membrane Water Electrolysis at Industrial‐Scale Current Density
Husileng Lee, Guoheng Ding, Linqin Wang, Yunxuan Ding, Tang Tang, Licheng Sun
Abstract
Abstract The development of non‐noble metal‐based hydrogen evolving reaction (HER) electrocatalysts operating under high current density plays a critical role in the large‐scale application of anion exchange membrane water electrolysis (AEM‐WE). Herein, a porous and hybrid MoS 2 /Ni 3 S 2 is synthesized on nickel foam (NF) via a one‐step hydrothermal method and studied its reconstruction process during alkaline HER conditions. Experimental results indicated that the MoS 2 underwent an oxidative dissolution followed by a dynamic equilibrium between dissolution and redeposition of the amorphous MoO x during HER. Meanwhile, S‐vacancy‐rich Ni 3 S 2 (A‐Ni 3 S 2 ) is exposed and acts as the real active site for HER. The obtained MoO x /A‐Ni 3 S 2 catalyst exhibited high catalytic performance in three‐electrode systems and single‐cell AEM‐WE. Finally, for a long‐term durability test in the AEM electrolyzer, a dry cathode method is applied to suppress the Mo species leaching from the MoO x /A‐Ni 3 S 2 electrode. Remarkably, the device assembled by MoO x /A‐Ni 3 S 2 as the cathode catalyst and NiFe as the anode catalyst demonstrated a high stability of 2500 h at 2 A cm −2 and 40 °C with a small aging rate of 30 µV h −1 .