High-performance anion exchange membrane water electrolyzer enabled by highly active oxygen evolution reaction electrocatalysts: Synergistic effect of doping and heterostructure

Anion exchange membrane water electrolyzers (AEM electrolyzers) have been demonstrated for efficient green hydrogen production. The primary advantage of AEM electrolyzers is replacing the noble metal catalysts with low-cost platinum group metal (PGM)-free catalysts. Despite some astonishing demonstrations of high-performance AEM electrolyzers [1] , [2] , [3] , [4] , most of them suffer from lower energy efficiency due to the poor catalytic activity of PGM-free catalysts. Herein, to improve the performance of AEM electrolyzers, we developed a CeO 2 /CoFeCe-layered double hydroxide (LDH) heterostructure as the OER catalyst. The Ce doping modulates the electronic structures of CoFe-LDH while creating a CeO 2 /CoFeCe LDH interface, which dramatically improves the OER activity. The Ce doping synergizes with the CeO 2 /CoFeCe LDH interface to enable a high-performance AEM electrolyzer, achieving an exceptional current density of 2.7 A/cm 2 at 1.8 V cell . This work validates that AEM electrolyzers equipped with PGM-free OER catalysts can achieve comparable energy efficiency with proton exchange membrane water electrolyzers (PEM electrolyzers). • The Ce doping improves the OER activity of CoFe LDH by modifying its electronic structure. • The CeO 2 /CoFeCe-LDH improves the OER activity by creating a new active interface between CeO 2 and CoFeCe-LDH. • The AEM electrolyzer catalyzed by CeO 2 /CoFeCe-LDH outperformed the electrolyzer with an IrO 2 benchmark electrocatalyst.