Efficient charge migration in TiO2@PB nanorod arrays with core–shell structure for photoelectrochemical water splitting

Herein, TiO2@Prussian-blue (PB) core–shell nanorod arrays for photoelectrochemical (PEC) applications were designed and prepared via a facile hydrothermal and electrodeposition process. Due to the combined merits of the anti-reflection structure of TiO2 nanorod arrays and broad light response of PB, the TiO2@PB film shows high light absorption efficiency. Additionally, the appropriate gradient energy gap of the core–shell heterostructure can promote photogenerated carrier separation and low electron–hole recombination rate. As a result, compared with TiO2 and PB films, the as-prepared TiO2@PB photoanode effectuates enhanced photocatalytic activity and the photocurrent density of TiO2@PB photoanode reaches 1.5 mA cm−2 at 1.23 V vs. RHE, which is approximately twice that of pristine TiO2 (0.75 mA cm−2). The introduction of the PB shell layer does not only improve light absorption ability but also enhances the photogenerated charge carrier's transfer and separation.