Li Jisi, Zheng Caiyan, Zhao Erling, Mao Jing, Cheng Yahui, Liu Hui, Hu Zhenpeng, Ling Tao
School of Materials Science and Engineering, Tianjin University, Tianjin 300072, China.
School of Physics, Nankai University, Tianjin 300071, China.
Proc Natl Acad Sci U S A. 2023 Oct 24;120(43):e2307901120. doi: 10.1073/pnas.2307901120. Epub 2023 Oct 16.
The efficiency of transition-metal oxide materials toward oxygen-related electrochemical reactions is classically controlled by metal-oxygen hybridization. Recently, the unique magnetic exchange interactions in transition-metal oxides are proposed to facilitate charge transfer and reduce activation barrier in electrochemical reactions. Such spin/magnetism-related effects offer a new and rich playground to engineer oxide electrocatalysts, but their connection with the classical metal-oxygen hybridization theory remains an open question. Here, using the MnVO family as a platform, we show that ferromagnetic (FM) ordering is intrinsically correlated with the strong manganese (Mn)-oxygen (O) hybridization of Mn oxides, thus significantly increasing the oxygen reduction reaction (ORR) activity. We demonstrate that this enhanced Mn-O hybridization in FM Mn oxides is closely associated with the generation of active Mn sites on the oxide surface and obtaining favorable reaction thermodynamics under operating conditions. As a result, FM-MnVO with a high degree of Mn-O hybridization achieves a record high ORR activity. Our work highlights the potential applications of magnetic oxide materials with strong metal-oxygen hybridization in energy devices.
过渡金属氧化物材料对与氧相关的电化学反应的效率传统上由金属 - 氧杂化控制。最近，有人提出过渡金属氧化物中独特的磁交换相互作用有助于电荷转移并降低电化学反应中的活化能垒。这种与自旋/磁性相关的效应为设计氧化物电催化剂提供了一个新的、丰富的领域，但它们与经典的金属 - 氧杂化理论的联系仍然是一个悬而未决的问题。在这里，以MnVO族为平台，我们表明铁磁（FM）有序与Mn氧化物中强的锰（Mn） - 氧（O）杂化本质上相关，从而显著提高氧还原反应（ORR）活性。我们证明，FM Mn氧化物中这种增强的Mn - O杂化与氧化物表面活性Mn位点的产生以及在操作条件下获得有利的反应热力学密切相关。结果，具有高度Mn - O杂化的FM - MnVO实现了创纪录的高ORR活性。我们的工作突出了具有强金属 - 氧杂化的磁性氧化物材料在能量装置中的潜在应用。
