Sun Yakun, Li Long, Li Xinxu, Feng Ya-Nan, Chen Fei-Fei, Li Lingyun, Yu Yan
Key Laboratory of Advanced Materials Technologies, International (HongKong Macao and Taiwan) Joint Laboratory on Advanced Materials Technologies, College of Materials Science and Engineering, Fuzhou University, Fuzhou 350108, China.
ACS Appl Mater Interfaces. 2023 Apr 5;15(13):16621-16630. doi: 10.1021/acsami.2c20402. Epub 2023 Mar 22.
Cobalt-based catalysts are ideal for CO reduction reaction (CORR) due to the strong binding and efficient activation of CO molecules on cobalt. However, cobalt-based catalysts also show low free energy of hydrogen evolution reaction (HER), making HER competitive with CORR. Therefore, how to improve the product selectivity of CORR while maintaining the catalytic efficiency is a great challenge. Here, this work demonstrates the critical roles of the rare earth (RE) compounds (ErO and ErF) in regulating the activity and selectivity of CORR on cobalt. It is found that the RE compounds not only promote charge transfer but also mediate the reaction paths of CORR and HER. Density functional theory calculations verify that the RE compounds lower the energy barrier of *CO → CO conversion. On the other hand, the RE compounds increase the free energy of HER, which leads to the suppression of HER. As a result, the RE compounds (ErO and ErF) improve the CO selectivity of cobalt from 48.8 to 69.6%, as well as significantly increase the turnover number by a factor of over 10.
由于钴对CO分子具有强吸附作用和高效活化能力，钴基催化剂是CO还原反应（CORR）的理想催化剂。然而，钴基催化剂的析氢反应（HER）自由能也较低，使得HER与CORR相互竞争。因此，如何在保持催化效率的同时提高CORR的产物选择性是一个巨大的挑战。在此，这项工作展示了稀土（RE）化合物（ErO和ErF）在调节钴上CORR的活性和选择性方面的关键作用。研究发现，RE化合物不仅促进电荷转移，还介导CORR和HER的反应路径。密度泛函理论计算证实，RE化合物降低了*CO→CO转化的能垒。另一方面，RE化合物增加了HER的自由能，从而抑制了HER。结果，RE化合物（ErO和ErF）将钴的CO选择性从48.8%提高到69.6%，同时将周转数显著提高了10倍以上。
