Controllable decoration of Ni-MOF on TiO2: Understanding the role of coordination state on photoelectrochemical performance

Decoration of metal-organic framework (MOF) has been considered as an effective route to improve the photoelectrochemical (PEC) performance of TiO 2 , but there is still a lack of understanding of the regulatory structure. Herein, Ni-MOF was rationally introduced by in-situ etching method, which helps for artificially regulating the coordination state of Ni sites. The photocurrent density (0.81 mA/cm 2 ) and IPCE value (33.1%) of TiO 2 -MOF-2 are about twice higher than that of pristine TiO 2 due to the rich unsaturated sites of Ni-MOF. Meanwhile, the saturated coordination has caused the decline of PEC performance because of the obvious steric hindrance . Therefore, this work presents an insight for the effect of coordination state on PEC activity especially in MOF system.