Self-healing mechanisms toward stable photoelectrochemical water splitting

Achieving stability poses a significant challenge in the practical implementation of photoelectrochemical (PEC) water splitting. The main factors affecting the long-term stability of PEC devices are chemical- and photo-corrosion of the semiconductor light absorbers, along with damage to the surface protection layer and the loss or reconstruction of the active centers of the co-catalysts. Introducing the concept of self-healing provides new strategies to enhance the stability of the semiconductor light absorbers, protection layer and co-catalysts in PEC water-splitting studies. Continuous exploration of these dynamic repair strategies is expected to promote the long-term stability of the PEC devices. This review outlines the deactivation mechanisms of different semiconductor light absorbers, protection layers, and co-catalysts under operational conditions. We further highlight corresponding regeneration and repair strategies, while addressing the challenges and prospects associated with constructing self-healing stable PEC water-splitting systems.