Metal–organic frameworks (MOFs) have recently been reported as promising catalysts for the oxygen evolution reaction (OER). Hence, we chose hydroxyl-rich 2,5-dihydroxyterephthalic acid as the ligand to prepare a novel MIL-100 and wrapped it on the NiCo-ZIF-67 surface to obtain an amorphous hollow material (NiCo-ZIF-67@Fe-MIL-100, denoted as NiCo-ZIF@MIL). The composite material presents a low overpotential (η ≈ 139 mV @ 10 mA cm⁻²), a small Tafel slope (119 mV dec⁻¹) and great stability for the OER in 1 M KOH solution. Density Functional Theory (DFT) calculations show that the hydroxyl-rich structure, which accelerates OH⁻ transfer and promotes the formation of the Co–O–Fe bridge, effectively reduces the reaction energy barrier (from 2.67 eV for NiCo-ZIF-67 to 2.08 eV for NiCo-ZIF@MIL). This work provides an important reference for the development of double-MOF materials.

中文翻译：

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新型非晶态 NiCo-ZIF@MIL-100 中的界面 Co-O-Fe 键合作为有效的活性位点，实现电催化水氧化

最近有报道称金属有机框架（MOF）是有前途的析氧反应（OER）催化剂。因此，我们选择富含羟基的2,5-二羟基对苯二甲酸作为配体，制备了新型MIL-100，并将其包裹在NiCo-ZIF-67表面，得到非晶中空材料（NiCo-ZIF-67@Fe-MIL） -100，表示为 NiCo-ZIF@MIL)。该复合材料在 1 M KOH 溶液中具有较低的过电势（η ≈ 139 mV @ 10 mA cm ^-2）、较小的塔菲尔斜率（119 mV dec ^-1）和出色的 OER 稳定性。密度泛函理论（DFT）计算表明，富含羟基的结构加速了OH ^-转移并促进Co-O-Fe桥的形成，有效降低了反应能垒（从NiCo-ZIF-67的2.67 eV到NiCo-ZIF@MIL 为 2.08 eV)。该工作为双MOF材料的开发提供了重要参考。