Dual-regulation charge separation strategy with the synergistic effect of 1D/0D heterostructure and inserted ferroelectric layer for boosting photoelectrochemical water oxidation

The poor visible light utilization and inferior charge separation efficiency of the TiO2 photoanode restrict its photoelectrochemical (PEC) activity for water oxidation. Therefore, herein, we report a dual-regulation charge separation strategy with a synergistic effect between a 1D/0D heterostructure and inserted ferroelectric layer in a TiO2/SrTiO3/CdS (nanorod/ferroelectric/quantum dot) composite photoanode to boost the PEC performance of TiO2. The ferroelectric SrTiO3 (STO) nanolayer exhibited a polar charge-induced electric field from the STO/CdS interface toward the TiO2/STO interface, resulting from strong and endurable spontaneous polarization. The polar charge-induced electric field, assisted by the TiO2/STO/CdS ternary heterojunction with cascade energy band alignment, simultaneously endowed persistent and rapid charge separation in the bulk and at TiO2/STO/CdS interfaces, which enhanced the charge separation efficiency by 148% compared to that of pure TiO2. Meanwhile, the obtained TiO2/STO/CdS photoanode allowed the integration of boosted charge carrier density, easier hole extraction and increased active sites from the outer CdS 0D quantum dots. Consequently, the TiO2/STO/CdS photoanode presented a prominently improved photocurrent of 1.85 mA cm−2 (at 1.23 V vs. RHE), which was 7.4 times that of TiO2. Thus, this integrated regulation strategy may open an avenue to pursue enhanced charge separation assisted by broadened light absorption for converting solar energy into fuel.