School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, 510641, P. R. China.
School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou, 510006, P. R. China.
Chemphyschem. 2023 Jun 1;24(11):e202300047. doi: 10.1002/cphc.202300047. Epub 2023 Mar 13.
Cu O is an attractive catalyst for the selective reduction of CO to methanol. However, the mechanism of the reaction and the role of the Cu species in different oxidation states are not well understood yet. In this work, by first-principles calculations, we investigate the mechanism of the reaction on the Cu O(110) surface, which is the most selective for methanol, in different degrees of reduction: ideal surface, slightly reduced surface (SRS), and partially reduced surface (PRS). The most favorable reaction pathways on the three surfaces were identified. We found that Cu(I) on the ideal surface is not capable of chemisorbing CO , but surface oxygen serves as the active site which selectively converts CO to CH OH with a limiting potential of -0.77 V. The Cu(0) on the SRS and PRS promotes the adsorption and reduction of CO , while the removal of the residue O* becomes potential/rate limiting with a more negative limiting potential than the ideal surface. The SRS is selective to methanol while the PRS becomes selective to methane. The result suggests that the key to high methanol selectivity is to avoid the reduction of Cu(I), which provides a new strategy for the design of more efficient catalysts for selective CO reduction to methanol.
氧化铜是一种很有吸引力的甲醇合成催化剂，用于选择性还原 CO。然而，反应的机理以及不同价态的铜物种的作用仍不清楚。在这项工作中，我们通过第一性原理计算，研究了在三种不同还原程度下（理想表面、轻度还原表面（SRS）和部分还原表面（PRS））对最具选择性的甲醇合成的 CuO(110)表面的反应机制。确定了三种表面上最有利的反应途径。我们发现理想表面上的 Cu(I)不能化学吸附 CO，而表面氧则是作为活性位，以 -0.77 V 的极限电势选择性地将 CO 转化为 CH3OH。SRS 和 PRS 上的 Cu(0)促进了 CO 的吸附和还原，而残留 O*的去除则成为势垒/速率限制步骤，具有比理想表面更负的极限电势。SRS 对甲醇具有选择性，而 PRS 则对甲烷具有选择性。结果表明，高甲醇选择性的关键是避免 Cu(I)的还原，这为设计更有效的 CO 选择性还原为甲醇的催化剂提供了新的策略。
