Chem. Sci., 2025, Accepted Manuscript DOI: 10.1039/D5SC04478B, Review Article Wen-Cheng Liu, YanQing Cai, Fangxing Xiao Photoelectrochemical (PEC) water splitting represents a highly promising technology to convert solar energy into clean and renewable chemical fuels. Among the divergent strategies utilized for customizing photoelectrodes, layer-by-layer (LbL) assembly...