Pursuing an environmentally friendly alternative to the Haber–Bosch process, using density functional theory (DFT) we explore further the merit of transition metal nitride (TMN) surfaces as catalysts for the nitrogen reduction reaction (NRR). Prior studies by our group have investigated the (100) and (111) facets of these TMNs and found the (100) to be favored in all cases. Many of the (100) facets of TMNs showed promising activity for ammonia (NH₃) formation. Recent experiments investigating the polycrystalline growth of these TMNs indicated the substantial presence of the (110) facet as well, and so we explore the properties of this surface orientation and compare it to the (100) facets previously reported. The only (110) facets of TMN that showed any promise was VN, but it suffered from high activation energies for N₂ adsorption compared to the activation energy of N migration from the bulk, which would likely lead to decomposition of the catalyst. The (110) facets showed overall worse catalytic activity than the (100). The most important outcome of this study is that the presence of the (110) facet of these TMNs in the catalyst structure will be detrimental to the activity of the catalyst. Great care must be taken when investigating the performance of these catalysts by engineering the surface to only include the surface orientation of interest.

为了寻求 Haber-Bosch 工艺的环保替代方案，我们使用密度泛函理论 (DFT) 进一步探索了过渡金属氮化物 (TMN) 表面作为氮还原反应 (NRR) 催化剂的优点。我们小组之前的研究调查了这些 TMN 的 (100) 和 (111) 方面，并发现 (100) 在所有情况下都受到青睐。TMN 的许多 (100) 个方面显示出对氨 (NH ₃) 形成。最近研究这些 TMN 多晶生长的实验表明 (110) 面也大量存在，因此我们探索了这种表面取向的特性，并将其与之前报道的 (100) 面进行了比较。TMN 的唯一 (110) 个方面表现出任何希望是 VN，但它受到 N _{2 的}高活化能的影响吸附与 N 从本体迁移的活化能相比，这可能导致催化剂分解。(110) 面的催化活性总体上比 (100) 面差。该研究最重要的结果是，催化剂结构中这些 TMN 的（110）面的存在将对催化剂的活性有害。在通过将表面设计为仅包括感兴趣的表面取向来研究这些催化剂的性能时，必须非常小心。