為了配合再生能源間歇的特性，氫能(Hydrogen energy)是一個便利且環保零排碳的潔淨能源載體，傳統上電解水(Water splitting)是快速製氫的方式，然而在陽極進行的產氧反應(Oxygen evolution reaction, OER)為整體電解水帶來較大的活化能障、並阻礙了氫能的發展；近年來研究者將目光轉向過渡金屬化合物(Transition metal compounds)，由於過渡金屬可以擁有多種價態的特性，研究這些高度多樣性的過渡金屬氧化物、氫氧化物、雜化物很有機會達到媲美或超過貴金屬催化劑的高效能與穩定性；其中，有機金屬框架材料(Metal organic frameworks, MOFs)是近幾年新興的熱門材料，由配位鍵構成的有序結構產生了孔洞性(Porosity)，同時藉由調整金屬及配位基(Ligand)可以控制其孔洞性質與反應活性，除了可以進行氣體吸附與存儲、偵測器以外，MOF的可調整性也被應用在(電)催化材料的設計上。
本研究設計出一套可於室溫下快速合成MOF的方法，以Co金屬及均苯三甲酸(Benzene-1,3,5-tricarboxylic acid, H3BTC)為主要成分，並添加少量Fe金屬以提升Co金屬之價態使其有利於吸附中間體OH-、對其進行氧化；實驗結果顯示合成出的FeCo7-MOF具有高度結晶性，並具有良好的OER效能及穩定性，經in-situ Raman光譜鑑定顯示，FeCo7-MOF在浸泡氫氧化鉀電解液後快速地轉化為羥基氧化物(Oxyhydroxide, MOOH)，並在施加電位下活化為MOO-形式進行催化，與文獻中過渡金屬施加電位後的活化結構一致，證明了活化位點的轉變。
為了進一步提升FeCo7-MOF材料的導電性，使用了Ti3C2Tx的二維材料進行複合，MXene優異的導電性使複合材料FeCo7-MOF/Ti3C2Tx在高電流密度時比FeCo7-MOF有更低的Tafel斜率，顯示出更優異的催化動力學，同時改變了速率決定步驟，而在電化學阻抗圖譜(Electrochemical impedance spectroscopy, EIS)上可得知電荷轉移電阻降低，證明此複合方式成功地藉由降低電阻提升了OER之表現。

Water splitting is composed of cathodic hydrogen evolution reaction (HER) and anodic oxygen evolution reaction (OER). However, the water splitting efficiency is hindered by a huge overpotential of 1.23 V. Recently, many efforts have been made to study OER electrocatalysts, such as metal oxide, hydroxide, or oxyhydroxide. Besides that, metal organic framework (MOF) is a novel topic in inorganic chemistry, which consists of metal node and organic linker. The framework usually collapses and transforms into OER active site when being applied with potential, making MOF become a candidate for OER electrocatalyst.
Here, we present the development of a FeCo7-MOF catalyst, which is constructed of highly connective H3BTC ligand. This catalyst can be easily and quickly prepared at room temperature using water as solvent. X-ray powder diffraction and infrared spectroscopy confirm the highly crystalline structure of the coordination network. Meanwhile, we introduce Ti3C2Tx as an additional substrate enhancing the conductivity of FeCo7-MOF.
The FeCo7-MOF/Ti3C2Tx heterostructure exhibits an overpotential of 260 mV to achieve a current density of 10 mA/cm2 and a corresponding Tafel slope of 48 mV/dec. These findings demonstrate a substantial breakthrough in OER efficiency for a bimetallic MOF heterostructure electrocatalyst system.

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