Herein, a hybrid structure of hematite (α‐Fe₂O₃) nanorod arrays is designed, with surface catalyzed by Co molecular complex (Co(dca)₂, dca: dicyanamide) and then protected by TiO₂ thin overlayer, for efficient and stable photoelectrochemical (PEC) water oxidation. The obtained α‐Fe₂O₃/Co(dca)₂/TiO₂ hybrid nanorod arrays show much improved and stabilized PEC performance as compared to the pristine, and even the Co(dca)₂ or TiO₂ modified α‐Fe₂O₃, with a photocurrent density of 0.35 mA cm^–2 obtained at 1.23 V vs. reversible hydrogen electrode (RHE), and an incident photon‐to‐current conversion efficiency (IPCE) reaching 16 % at 400 nm at 1.6 V vs. RHE. It has been demonstrated that the adsorbed Co(dca)₂ molecular complex could effectively promote the interface charge transfer process and accelerate the water oxidation reaction kinetics, meanwhile the atomic layer deposited TiO₂ overlayer could passivate the surface defects of α‐Fe₂O₃ and suppress the surface charge carrier recombination. Moreover, the TiO₂ overlayer could effectively protect Co(dca)₂ from detaching from the α‐Fe₂O₃ surface and thus stabilize the PEC activity for water oxidation reaction. The present study provides some available thoughts and methods for rational design of highly efficient photoelectrodes for water splitting from the perspective of the surface and interface engineered charge carrier transfer and water oxidation processes.

中文翻译：

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具有分子复合助催化剂的受保护的赤铁矿纳米棒阵列，可实现高效，稳定的光电化学水氧化

在此，（α-铁赤铁矿的混合结构₂ ö ₃）纳米棒阵列被设计，以表面被Co分子复合物（钴（DCA）催化₂，DCA：二氰胺），然后通过二氧化钛的保护₂薄覆盖层，用于有效和稳定的光电化学（PEC）水氧化。将所得的α-Fe ₂ ö ₃ /钴（DCA）₂ /的TiO _2个混合纳米棒阵列表现出很大的提高和稳定PEC性能相比原始如，甚至钴（DCA）₂或TiO ₂改性的α-Fe ₂ ö ₃，光电流密度为0.35 mA cm ^–2相对于可逆氢电极（RHE）在1.23 V下获得的光通量，而相对于RHE在1.6 V下在400 nm处的入射光子-电流转换效率（IPCE）达到16％。已经证明的是，吸附的Co（DCA）₂分子复合物可以有效地促进界面的电荷转移过程和加速水的氧化反应动力学，同时原子层沉积的TiO ₂覆盖层可以钝化的表面缺陷的α-Fe ₂ ö ₃并抑制表面电荷载流子复合。此外，在TiO ₂覆层能有效保护的Co（DCA）₂从分离的α-Fe ₂ ö ₃表面，从而稳定了PEC的水氧化反应活性。从表面和界面工程载流子转移和水氧化过程的角度，本研究为合理设计用于水分解的高效光电电极提供了一些可行的思想和方法。