Polycrystalline ferroelectric BiFeO3 (BFO) films deposited on transparent indium tin oxide (ITO) electrodes have shown to be an interesting photocathode for photoelectrochemical (PEC) water splitting; however, its PEC performance and stability are far from perfection. Herein, we reported an amorphous TiO2 buffer layer, inserted between BFO and Pt catalyst, improves significantly both its PEC activity and stability. A photocathodic current density of −460 μA/cm2 at 0 V vs. reversible hydrogen electrode (RHE) and an onset potential of 1.25 V vs. RHE were obtained in ITO/BFO/TiO2/Pt photocathode under 100 mW/cm2 Xe-lamp illumination. TiO2 functions as a buffer layer to remove the upward barrier between BFO and Pt, and makes the photogenerated carriers separate efficiently. The photocathode also shows high stability in acid solution after a 10-h PEC continuous testing.

中文翻译：

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TiO2 缓冲层在 Pt 催化的 BiFeO3 光电阴极中的双重作用：提高效率和表面保护

沉积在透明氧化铟锡 (ITO) 电极上的多晶铁电 BiFeO3 (BFO) 薄膜已被证明是一种有趣的光电化学 (PEC) 水分解光电阴极；然而，其PEC性能和稳定性远非完美。在此，我们报道了一种插入在 BFO 和 Pt 催化剂之间的无定形 TiO2 缓冲层，显着提高了其 PEC 活性和稳定性。在 100 mW/cm2 氙灯下，在 ITO/BFO/TiO2/Pt 光电阴极中获得了 -460 μA/cm2 的光电阴极电流密度，相对于可逆氢电极 (RHE) 和 1.25 V 相对于 RHE 的起始电位照明。TiO2 作为缓冲层去除 BFO 和 Pt 之间的向上势垒，并使光生载流子有效分离。