Nickel-based alloys have been recognized as promising catalysts for upgrading of bio-oils because of their superior deoxygenation activity. Herein, we present a density-functional theory study on hydrodeoxygenation (HDO) of catechol on three Ni-based (111) surfaces, namely Ni(111), bimetallic Fe@Ni(111) single-atom alloy and NiFe(111) homogeneous alloy. The results show that the partial hydrogenation (PH) and/or transhydrogenation (TH) followed by dehydroxylation (DO) are the dominant reaction pathways of catechol HDO towards phenol formation on the three Ni-based (111) surfaces. Specially, TH via *H-and-metal-assisted intramolecular H-transfer is identified as an effective hydrogenation route with a lowered activation barrier compared to the conventional hydrogenation mechanism catalyzed by metals. It is revealed that the deoxygenation performance in catechol HDO can be greatly enhanced by increasing the content of alloyed oxophilic Fe, which, however, could cause the side effect of difficult removal of over-bound *OH on an over-oxophilic surface. The composition of a secondary oxophilic metal in an alloyed surface should be an optimizable parameter as important as altering oxophilic metals alloyed into an active metal phase.

中文翻译：

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揭示嗜氧金属在促进镍基合金催化剂上邻苯二酚脱氧中的作用

镍基合金因其卓越的脱氧活性而被公认为是提高生物油品质的催化剂。在这里，我们提出密度泛函理论研究儿茶酚在三个镍基（111）表面上的邻苯二酚加氢脱氧（HDO），即镍（111），双金属Fe @ Ni（111）单原子合金和均匀的NiFe（111）合金。结果表明，部分氢化（PH）和/或转氢（TH）继而进行脱羟基（DO）是邻苯二酚HDO在三个镍基（111）表面上形成苯酚的主要反应途径。特别是TH通过*与金属催化的常规氢化机理相比，H和金属辅助的分子内H转移被认为是一种有效的氢化途径，其活化势垒降低。揭示了通过增加合金化的亲氧性铁的含量可以大大提高邻苯二酚HDO的脱氧性能，但是，这可能导致难以去除过氧表面上过量的* OH的副作用。合金表面中次生嗜氧金属的成分应为可优化的参数，与改变合金化为活性金属相的嗜氧金属一样重要。