A stable heterometallic (Co, Ni)-MOF array with a 3D hierarchical flower-like morphology was coated onto the coral-like WO/W thin film. The optimal (Co, Ni)-MOF/WO/W photoanode exhibits a high photocurrent density of 2.96 mA cm at 1.23 V in the 0.5 M NaSO solution and the photoelectrochemical (PEC) cell displays an excellent solar-to-hydrogen (STH) efficiency (2.17 %) under AM 1.5 G solar light. Moreover, the separation behavior and spatial distribution of photogenerated charges have been demonstrated by photo-assisted Kelvin probe force microscopy (KPFM). Furthermore, the shift of the -band center and the change of Gibbs free energy for oxygen evolution reaction (OER) are realized by density functional theory (DFT) calculations. Overall, the coupling effect of these ions of Co, O, Ni, and W could result in an electron delocalization in the (Co, Ni)-MOF/WO/W photoanode, boosting the OER activity and finally improving the PEC water splitting performance.

中文翻译：

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调控花状 (Co, Ni)-MOF 阵列和 WO3/W 光电阳极之间的电子离域，实现有效的光电化学水分解

将具有 3D 分层花状形态的稳定异金属 (Co, Ni)-MOF 阵列涂覆在珊瑚状 WO/W 薄膜上。最佳的 (Co, Ni)-MOF/WO/W 光阳极在 0.5 M NaSO 溶液中在 1.23 V 下表现出 2.96 mA cm 的高光电流密度，并且光电化学 (PEC) 电池表现出优异的太阳能制氢 (STH) AM 1.5 G 太阳光下的效率 (2.17 %)。此外，光辅助开尔文探针力显微镜（KPFM）已经证明了光生电荷的分离行为和空间分布。此外，通过密度泛函理论（DFT）计算实现了能带中心的移动和析氧反应（OER）吉布斯自由能的变化。总体而言，Co、O、Ni 和 W 离子的耦合效应可能导致 (Co, Ni)-MOF/WO/W 光阳极中的电子离域，从而提高 OER 活性，最终提高 PEC 水分解性能。