Insights on cold plasma ammonia synthesis and decomposition using alkaline earth metal-based perovskites
Insights on cold plasma ammonia synthesis and decomposition using alkaline earth metal-based perovskites
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DOI：
10.1039/d1cy00729g
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发表时间：
2021-06-08
影响因子：
5
通讯作者：
Carreon, Maria L.
中科院分区：
文献类型：
--
作者：
Gorky, Fnu;Lucero, Jolie M.;Carreon, Maria L.
固体催化剂与等离子体协同合成氨的研究近来引起了科学界的极大兴趣。在此，我们探索MgTiO 3，CaTiO 3，SrTiO 3和BaTiO 3钙钛矿作为有效的催化剂，用于通过冷等离子体合成和分解氨。MgTiO 3钙钛矿，其包含所有研究的钙钛矿中电负性最强的碱金属，导致最高的氨合成速率，其值为12.16 μ mol min（-1）m（-2），这是仅等离子体的值（0.24 μ mol min（-1））的约50倍。Mg的高电负性可以帮助三氮共价键的解离。Mg钙钛矿的这种固有性质添加到由该钙钛矿的介电常数值引起的等离子体的均匀性中，可能协同地负责观察到的高氨合成速率。有趣的是，MgTiO 3钙钛矿上的氨产量几乎是传统氧化物和一些微孔晶体性能的两倍。我们还探讨了氨分解反应，由于可逆反应的重要性，由于电子碰撞与氨分子形成的可能性。氨分解随着等离子体功率的增加而增加。这指出了在低等离子体功率下运行的好处，以及设计等离子体反应器的需要，其中新形成的氨分子可以从反应系统中去除，以避免进一步的电子碰撞。在20 W时，最高氨分解率为44.37%，对应的能量产率为5.06 g-NH3 kW·h（-1）。
The synergistic combination of solid catalysts and plasma for the synthesis of ammonia has recently attracted considerable scientific interest. Herein, we explore MgTiO3, CaTiO3, SrTiO3, and BaTiO3 perovskites as effective catalysts for the synthesis and decomposition of ammonia via cold plasma. MgTiO3 perovskite, which contains the most electronegative alkaline metal of all the studied perovskites, resulted in the highest ammonia synthesis rate with a value of 12.16 mu mol min(-1) m(-2), which is around 50 times the value of only plasma, 0.24 mu mol min(-1). The high electronegativity of Mg can be assisting the dissociation of the triple nitrogen covalent bond. This intrinsic property of Mg perovskite added to the homogeneity of the plasma arising from the dielectric constant value of this perovskite might be synergistically responsible for the high ammonia synthesis rate observed. Interestingly, ammonia production over MgTiO3 perovskite is almost double the performance of traditional oxides and some microporous crystals. We also explored the ammonia decomposition reaction due to the possibility of the importance of the reversible reaction owing to the electron collision with the ammonia molecules formed. Ammonia decomposition increased as plasma power increased. This points out the benefit of running at low plasma power and the need to design plasma reactors where the newly formed ammonia molecules can be removed from the reaction system to avoid further electron collision. The highest ammonia decomposition yield was 44.37% at 20 W corresponding to an energy yield of 5.06 g-NH3 kW h(-1).