四川大学吴家刚团队揭示dx2-y2电子态在镍基氢氧化甲醇电催化剂中的关键作用。相关研究成果发表在2024年4月15日出版的《德国应用化学》。

阳极甲醇氧化反应（MOR）在与阴极析氢反应（HER）的耦合中起着至关重要的作用，并使高价值甲酸盐的可持续生产成为可能。镍基氢氧化物(Ni(OH)₂)作为MOR电催化剂引起了人们的极大关注。然而，决定本征催化活性的关键因素仍然未知，这严重阻碍了Ni(OH)₂电催化剂的进一步发展。

该文中，研究人员发现反键带内的dx2-y2电子态在整个MOR过程中起着决定性的作用。起始电势取决于去质子化能力（Ni²⁺到Ni³⁺），这与dx2-y2轨道的能带中心密切相关。dx2-y2轨道越接近费米能级，其去质子化能力越强。同时，在高电位区，dx2-y2轨道的加宽将促进电子从甲醇转移到催化剂（Ni³+到Ni²⁺），进一步提高催化性能。

该工作首次阐明了dx2-y2电子态与MOR活性之间的内在关系，为甲醇电氧化研究领域增添了新的理解。

附：英文原文

Title: Unveiling the Pivotal Role of dx2-y2 Electronic States in Nickel-based Hydroxide Electrocatalysts for Methanol Oxidation

Author: Junhua Li, Chao Wu, Zhen Wang, Haoyan Meng, Qi Zhang, Ying Tang, Anqi Zou, Yiming Zhang, Haoyin Zhong, Shibo Xi, Junmin Xue, Xiaopeng Wang, Jiagang Wu

Issue&Volume: 2024-04-15

Abstract: The anodic methanol oxidation reaction (MOR) plays a crucial role in coupling with the cathodic hydrogen evolution reaction (HER) and enables the sustainable production of the high-valued formate. Nickel-based hydroxide (Ni(OH)2) as MOR electrocatalyst has attracted enormous attention. However, the key factor determining the intrinsic catalytic activity remains unknown, which significantly hinders the further development of Ni(OH)2 electrocatalyst. Here, we found that the dx2-y2 electronic state within antibonding bands plays a decisive role in the whole MOR process. The onset potential depends on the deprotonation ability (Ni2+ to Ni3+), which was closely related to the band center of dx2-y2 orbital. The closer of dx2-y2 orbital to the Fermi level showed the stronger the deprotonation ability. Meanwhile, in the high potential region, the broadening of dx2-y2 orbital would facilitate the electron transfer from methanol to catalysts (Ni3+ to Ni2+), further enhancing the catalytic properties. Our work for the first time clarifies the intrinsic relationship between dx2-y2 electronic state and the MOR activities, which adds a new layer of understanding to the methanol electrooxidation research scene.

DOI: 10.1002/anie.202404730

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202404730