Interface Engineering of CoFe-LDH Modified Ti: α-FeO Photoanode for Enhanced Photoelectrochemical Water Oxidation.

Effectively regulating and promoting the charge separation and transfer of photoanodes is a key and challenging aspect of photoelectrochemical (PEC) water oxidation. Herein, a Ti-doped hematite photoanode with a CoFe-LDH cocatalyst loaded on the surface was prepared through a series of processes, including hydrothermal treatment, annealing and electrodeposition. The prepared CoFe-LDH/Ti:α-FeO photoanode exhibited an outstanding photocurrent density of 3.06 mA/cm at 1.23 V, which is five times higher than that of α-FeO alone. CoFe-LDH modification and Ti doping on hematite can boost the surface charge transfer efficiency, which is mainly attributed to the interface interaction between CoFe-LDH and Ti:α-FeO. Furthermore, we investigated the role of Ti doping in enhancing the PEC performance of CoFe-LDH/Ti:α-FeO. A series of characterizations and theoretical calculations revealed that, in addition to improving the electronic conductivity of the bulk material, Ti doping also further enhances the interface coupling of CoFe-LDH/α-FeO and finely regulates the interfacial electronic structure. These changes promote the rapid extraction of holes from hematite and facilitate charge separation and transfer. The informative findings presented in this work provide valuable insights for the design and construction of hematite photoanodes, offering guidance for achieving excellent performance in photoelectrochemical (PEC) water oxidation.