Hematite is a strategical material for photoelectrochemical (PEC) water splitting due to their abundance, stability, non-toxicity, and outstanding electrical and optical properties. However, its limited charge transfer has been challenging towards solar energy conversion. In this work, we show an efficient and novel strategy to improve the charge transfer of hematite photoanode by the formation of a heterostructure with doped TiO₂ using metal transition ions (X = Co, Cu, Bi). The results indicated that the PEC water splitting performance of the α-Fe₂O₃-TiO₂:X photoanodes were improved according to Bi > Cu > Co metal ions. The photoconversion efficiency was increased 5.5 times in the Bi-doped sample, along with an increment in the charge separation efficiency of 2.5 times. This improvement was related to the charge carrier dynamics: a high visible light absorption, low recombination, and efficient charge separation. EIS analysis showed a higher donor density in the doped samples, which implies a high carrier concentration and conductivity, improving the electron-hole transport efficiency of the photoelectrochemical performance.

赤铁矿因其丰富，稳定，无毒以及出色的电学和光学特性而成为光化学（PEC）水分解的战略材料。然而，其有限的电荷转移一直对太阳能转换具有挑战性。在这项工作中，我们展示了一种有效且新颖的策略，可通过使用金属过渡离子（X = Co，Cu，Bi）与掺杂的TiO ₂形成异质结构来改善赤铁矿光电阳极的电荷转移。结果表明，所述的PEC水分解性能的α-Fe ₂ ö ₃ -TiO ₂根据Bi> Cu> Co金属离子改善了：X光阳极。在Bi掺杂的样品中，光转换效率提高了5.5倍，而电荷分离效率提高了2.5倍。这种改进与电荷载流子动力学有关：高可见光吸收，低重组率和有效的电荷分离。EIS分析表明掺杂样品中的供体密度更高，这意味着高的载流子浓度和电导率，提高了光电化学性能的电子-空穴传输效率。