Chen Long, Jiang Li-Wen, Wang Jian-Jun
State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China.
Shenzhen Research Institute, Shandong University, Shenzhen 518057, China.
Molecules. 2023 Oct 9;28(19):6986. doi: 10.3390/molecules28196986.
Transition metal alloys have emerged as promising electrocatalysts due to their ability to modulate key parameters, such as d-band electron filling, Fermi level energy, and interatomic spacing, thereby influencing their affinity towards reaction intermediates. However, the structural stability of alloy electrocatalysts during the alkaline hydrogen evolution reaction (HER) remains a subject of debate. In this study, we systematically investigated the structural evolution and catalytic activity of the -Co/CoMo electrocatalyst under alkaline HER conditions. Our findings reveal that the CoMo alloy and HMoO exhibit instability during alkaline HER, leading to the breakdown of the crystal structure. As a result, the cubic phase -Co undergoes a conversion to the hexagonal phase -Co, which exhibits strong catalytic activity. Additionally, we identified hexagonal phase Co(OH) as an intermediate product of this conversion process. Furthermore, we explored the readsorption and surface coordination of the Mo element, which contribute to the enhanced catalytic activity of the -Co/CoMo catalyst in alkaline HER. This work provides valuable insights into the dynamic behavior of alloy-based electrocatalysts, shedding light on their structural stability and catalytic activity during electrochemical reduction processes.
过渡金属合金因其能够调节诸如d带电子填充、费米能级能量和原子间距等关键参数，从而影响其对反应中间体的亲和力，已成为有前景的电催化剂。然而，合金电催化剂在碱性析氢反应（HER）过程中的结构稳定性仍是一个有争议的话题。在本研究中，我们系统地研究了-Co/CoMo电催化剂在碱性HER条件下的结构演变和催化活性。我们的研究结果表明，CoMo合金和HMoO在碱性HER过程中表现出不稳定性，导致晶体结构的破坏。结果，立方相-Co转变为具有强催化活性的六方相-Co。此外，我们确定六方相Co(OH)是该转变过程的中间产物。此外，我们还探索了Mo元素的再吸附和表面配位，这有助于增强-Co/CoMo催化剂在碱性HER中的催化活性。这项工作为基于合金的电催化剂的动态行为提供了有价值的见解，揭示了它们在电化学还原过程中的结构稳定性和催化活性。
