Recent progresses on Janus electrocatalysts for water electrolysis: A critical review

Newly emerged Janus materials showed the vast potential for catalysis and photocatalysis owing to their multifunctional properties, attracting attention as next-generation functional materials. This Review focuses on various synthesis processes for developing a novel class of Janus materials for applications in electrocatalysis and photo-electrocatalysis via water electrolysis. Starting with summarizing the different designs and preparation of Janus particles, this Review analyzed the compositions and categories of Janus materials. Furthermore, this Review discusses various synthesis processes of Janus materials, followed by classifications of different synthesis routes for Janus materials with a detailed review of the respective process parameters, multifunctional properties, and present status of their development. This Review also summarizes the comprehensive properties of the Janus material, subjected to their applications toward catalytic hydrogen evolution reactions, oxygen evolution reactions, and photo-electrocatalysis. Finally, a thorough summary is presented on the synthesis and applications of Janus particle, while the respective challenges and outlooks are also discussed.