Nitrogen gas seeding is considered as an effective strategy to reduce the edge plasma temperature. The tungsten nitride compounds, which could form on the top of tungsten (W) first wall due to nitrogen gas seeding, may act as a barrier to hinder the diffusion of hydrogen (H) from the tungsten nitride layer to W first wall. By performing first-principles calculations, we investigate the dissolution, diffusion and retention behaviors of H in W₂N₁, W₁N₁ and W₂N₃, respectively. It is found that a H atom prefers to dissolve in tungsten nitride compounds than in W crystal. Hence the compounds can act as a barrier against H diffusion to W first wall, and probably reducing the hydrogen retention in W first wall. All of these behaviors are essentially correlated with the formation of strong N-H bonding in the compounds once H atoms dissolve in them. Moreover, our calculations indcate that H atoms do not form hydrogen molecules even within a vacancy, but stay separately from each other due to the formation of strong N-H bonding. Our work not only proposes that tungsten nitride compounds can significantly reduce hydrogen retention in W first wall, but provides a fundamental insight in understanding the interactions of H with tungsten nitride compounds.

氮气播种被认为是降低边缘等离子体温度的有效策略。由于氮气注入而可能在钨（W）第一壁的顶部上形成的氮化钨化合物可以充当阻挡层，以阻止氢（H）从氮化钨层扩散到钨（W）第一壁。通过进行第一性原理计算，我们研究了H在W ₂ N ₁，W ₁ N ₁和W ₂ N _3中的溶解，扩散和保留行为。， 分别。发现H原子比W晶体更优选溶解在氮化钨化合物中。因此，这些化合物可以充当阻止H扩散到W第一壁的屏障，并可能减少氢在W第一壁中的保留。一旦H原子溶解在化合物中，所有这些行为基本上都与化合物中牢固的NH键形成有关。此外，我们的计算表明，即使在空位内，H原子也不会形成氢分子，而是由于形成牢固的NH键而彼此分开。我们的工作不仅提出氮化钨化合物可以显着减少W第一壁中的氢保留，而且为理解H与氮化钨化合物的相互作用提供了基本的见识。