Deactivation mechanism for water splitting: Recent advances

Abstract

Hydrogen (H₂) has been regarded as a promising alternative to fossil-fuel energy. Green H₂ produced via water electrolysis (WE) powered by renewable energy could achieve a zero-carbon footprint. Considerable attention has been focused on developing highly active catalysts to facilitate the reaction kinetics and improve the energy efficiency of WE. However, the stability of the electrocatalysts hampers the commercial viability of WE. Few studies have elucidated the origin of catalyst degradation. In this review, we first discuss the WE mechanism, including anodic oxygen evolution reaction (OER) and cathodic hydrogen evolution reaction (HER). Then, we provide strategies used to enhance the stability of electrocatalysts. After that, the deactivation mechanisms of the typical commercialized HER and OER catalysts, including Pt, Ni, RuO₂, and IrO₂, are summarized. Finally, the influence of fluctuating energy on catalyst degradation is highlighted and in situ characterization methodologies for understanding the dynamic deactivation processes are described.

Keywords

deactivation mechanism / hydrogen evolution / in situ characterization / oxygen evolution / water splitting