Flexible Electrocatalyst Engineering Based on 2D Ultrathin Nanosheets and Lamellar Fern‐Like Aerogel for Water Electrolysis

Abstract Water electrolysis represents the primary method to produce green hydrogen. Nevertheless, during water electrolysis, particularly at high current densities, a large number of gas bubbles generated are difficult to detach from the electrode, triggering a series of negative effects such as active site covering, ionic conductance block, and catalyst deactivation, which in turn reduces catalyst efficiency. In recent years, flexible electrocatalysts have been developed to address this issue well, with the superior characteristics including mechanical deformability, active site optimization, high mass transfer efficiency, and structural stability. The advanced development of flexible electrocatalyst engineering for water electrolysis is urgently needed to be systematically reviewed. Here, first, the characteristics of flexible electrocatalysts are summarized to deeply understand their impact on water electrolysis performance. Second, a series of strategies to design flexible electrocatalysts based on 2D nanosheets and fern‐like structure are comprehensively introduced. Last but not least, the outlooks of flexible electrocatalyst research is presented, which will provide a preliminary theoretical basis and new ideas for the development of low‐cost, high‐performance, and long‐life electrocatalysts applied to water electrolysis.