Collapsing the Bottleneck by Interfacial Effect of Ni/CeO 2 for Long‐Term Hydrogen Production using Waste Alkaline Water in Practical‐Scale Anion Exchange Membrane Water Electrolyzer

Abstract The demand for hydrogen production compels the development of various strategies for water splitting. Among these strategies, the Anion Exchange Membrane Water Electrolyzer (AEMWE) offers the advantages such as low cost and the production of high‐purity hydrogen. Waste alkaline water generated from various industries can be directly used in the AEMWE system, due to its appropriate pH range of 13–14. While various nickel‐based hydrogen evolution reaction (HER) electrocatalysts have demonstrated adequate performance, their long‐term stability remains a concern. To ensure long‐term stability of AEMWE, it is crucial to address the potential poisoning effects of impurities present in waste alkaline water on nickel‐based HER electrocatalysts. In this study, the Ni‐CeO₂/Carbon (NCC) catalyst is employed for HER in waste alkaline water containing Li, Mo, and W ions. NCC exhibited an overpotential of 31 mV, showing ≈3 times less overpotential compared to the Ni/C. The XPS results and DFT calculations demonstrated the electrons transferring from CeO 2 to Ni, inducing the Electronic Metal‐Support Interactions (EMSI) effects. The NCC shows 1 A cm −2 at 2.03 V in AEMWE while Ni/C needed 2.33 V to achieve the same current densities. The NCC maintaines long‐term stability over 2000 h, with a degradation rate of 4.95%.