Yu Zhou, Li Jian-Ping, Xu Xian-Kun, Ding Zhong-Chen, Peng Xiao-Hui, Gao Yi-Jing, Wan Qiang, Zheng Ju-Fang, Zhou Xiao-Shun, Wang Ya-Hao
Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Institute of Physical Chemistry, College of Chemistry and Materials Science, Zhejiang Normal University, Jinhua, 321004, P. R. China.
Zhejiang Engineering Laboratory for Green Syntheses and Applications of Fluorine-Containing Specialty Chemicals, Institute of Advanced Fluorine-Containing Materials, Zhejiang Normal University, Jinhua, 321004, P. R. China.
Adv Sci (Weinh). 2025 Jun;12(22):e2417607. doi: 10.1002/advs.202417607. Epub 2025 Mar 30.
The success of different heterogeneous strategies of organometallic catalysts has been demonstrated to achieve high selectivity and activity in photo/electrocatalysis. However, yielding their catalytic mechanisms at complex molecule-electrode and electrochemical interfaces remains a great challenge. Herein, shell-isolated nanoparticle-enhanced Raman spectroscopy is employed to elucidate the dynamic process, interfacial structure, and intermediates of copper hydroxide-2-2' bipyridine on Au electrode ((bpy)Cu(OH)/Au) during the oxygen evolution reaction (OER). Direct Raman molecular evidences reveal that the interfacial (bpy)Cu(OH) oxidizes into Cu(III) and bridges to Au atoms via oxygenated species, forming (bpy)Cu(III)O-Au with oxygen-bridged binuclear metal centers of Cu(III)-O-Au for the OER. As the potential further increases, Cu(III)-O-Au combines with surface hydroxyl groups (*OH) to form the important intermediate of Cu(III)-OOH-Au, which then turns into Cu(III)-OO-Au to release O. Furthermore, in situ electrochemical impedance spectroscopy proves that the Cu(III)-O-Au has lower resistance and faster mass transport of hydroxy to enhance OER. Theoretical calculations reveal that the formation of Cu(III)-O-Au significantly modify the elementary reaction steps of the OER, resulting in a lower potential-determining step of ≈0.58 V than that of bare Au. This work provides new insights into the OER mechanism of immobilized-molecule catalysts for the development and application of renewable energy conversion devices.
已证明有机金属催化剂的不同异质策略在光催化/电催化中能够实现高选择性和活性。然而，要揭示其在复杂分子-电极和电化学界面处的催化机制仍然是一项巨大的挑战。在此，采用壳层隔离纳米颗粒增强拉曼光谱来阐明氢氧化铜-2,2'-联吡啶在金电极（(bpy)Cu(OH)/Au）上析氧反应（OER）过程中的动态过程、界面结构和中间体。直接的拉曼分子证据表明，界面处的(bpy)Cu(OH)氧化为Cu(III)，并通过含氧物种与金原子桥连，形成具有Cu(III)-O-Au氧桥双核金属中心的(bpy)Cu(III)O-Au用于OER。随着电位进一步升高，Cu(III)-O-Au与表面羟基（*OH）结合形成重要中间体Cu(III)-OOH-Au，然后转变为Cu(III)-OO-Au以释放O。此外，原位电化学阻抗谱证明Cu(III)-O-Au具有更低的电阻和更快的羟基传质速率以增强OER。理论计算表明，Cu(III)-O-Au的形成显著改变了OER的基元反应步骤，导致其电位决定步骤比裸金的电位决定步骤低约0.58V。这项工作为固定化分子催化剂的OER机制提供了新的见解，有助于可再生能源转换装置的开发和应用。
