The practical application of the most promising α-Fe₂O₃ photoanode in solar hydrogen generation is facing an awkward challenge arising from its poor bulk carrier transport. Present work demonstrates the acceleration of the carrier transport via embedding the p-type Ti-defected TiO₂ (TiO₂-V_Ti) nanocrystals in the n-type Fe₂O₃ photoanode matrix, which results in significantly improved photoelectrochemical performance. By embedding sub-5 nm TiO₂-V_Ti nanocrystals in the bulk of α-Fe₂O₃ photoanode, numerous p-n nano-heterointerfaces were constructed for the first time in Fe₂O₃ photoanode matrix. The formed p-n nano-heterointerfaces lead to 10 times enhancement of charge transfer rate constant (k_tran), and 1.5 times reduction of the charge recombination rate constant (k_rec), which is due to the formation of the built-in electric fields and effective carrier transport and separation at the p-n nano-heterointerfaces of TiO₂-V_Ti/Fe₂O₃. Such strategy leads to the Fe₂O₃ photoanode with a reduction of photogenerated carrier transport time by 3 times, resulting in an excellent photocurrent density as high as 1.45 mA cm⁻² at 1.23 V_RHE, 5 times higher than that of pristine hematite (0.27 mA cm⁻²). We thus believe that our study opens up a route to regulate hematite or even metal-oxide semiconductor chemical/physical features via p-n nano-heterostructure embedding.

最有前途的α-Fe ₂ O ₃光阳极在太阳能制氢中的实际应用面临着由于其较差的载流子传输而产生的尴尬挑战。目前的工作表明，通过将p型Ti缺陷TiO ₂ (TiO ₂ -V _Ti )纳米晶体嵌入n型Fe ₂ O ₃光阳极基质中，可以加速载流子传输，从而显着提高光电化学性能。通过将亚 5 nm TiO ₂ -V _{Ti纳米晶体嵌入 α-Fe 2} O ₃块体中光阳极方面，首次在Fe ₂ O ₃光阳极基质中构建了多个pn纳米异质界面。形成的pn纳米异质界面导致电荷转移速率常数（k _{tran ）提高10倍，电荷复合速率常数（} k _rec ）降低1.5倍，这是由于内建电场和TiO ₂ -V _Ti /Fe ₂ O ₃的pn纳米异质界面处的有效载流子传输和分离。这种策略导致 Fe ₂ O ₃光阳极的光生载流子传输时间减少了3倍，在1.23 V _RHE下产生高达1.45 mA cm ^-2的优异光电流密度，比原始赤铁矿（0.27 mA cm ^-2）高5倍。因此，我们相信我们的研究开辟了一条通过 pn 纳米异质结构嵌入来调节赤铁矿甚至金属氧化物半导体化学/物理特征的途径。