 Residual CL ligands are found critical to the stability of amorphous TiO2 coatings by atomic layer deposition. Here, in situ water treatment is developed to remove residual CL, while preserve its uniform amorphous phase, which improves the lifetime of cyphotoanode to 600H for hydrogen production. This article was authored by Yu Tao Dong, Madad O Bossi, Zhang Meng, and others.