Ammonia synthesis via the high-temperature and -pressure Haber–Bosch (HB) process at large centralized facilities has a significant contribution to global CO₂ emissions. Radically new catalysts should be discovered to enable sustainable ammonia synthesis processes that can operate at much lower temperatures to relax the demand for high pressure in the current HB process. In this manner, the capital requirement and energy consumption for making ammonia would decrease considerably and a de-centralized production could become feasible. Herein, we present a new class of ruthenium-based catalysts promoted with metallic cesium using an in situ preparation technique. The catalysts prepared with this new technique showed up to a factor of ∼10 higher activity compared to the ones prepared by traditional ex situ promotion methods. The in situ promoted catalyst also has a smaller apparent activation energy and is less susceptible to H₂ poisoning. We systematically investigate the promotional role of in situ dosed Cs and propose a detailed model supported by extensive density functional theory calculations to explain the difference between the promotional effect of the in situ and traditionally ex situ prepared catalysts.

中文翻译：

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通过原位投加 Cs 增强对 Ru 基氨催化剂的促进作用

在大型集中设施中通过高温高压 Haber-Bosch (HB) 工艺合成氨对全球 CO ₂排放有重大贡献。应该发现全新的催化剂，以实现可持续的氨合成工艺，该工艺可以在低得多的温度下运行，从而缓解当前 HB 工艺中对高压的需求。通过这种方式，制造氨的资本需求和能源消耗将大大降低，分散生产变得可行。在此，我们提出了一种新型的金属铯促进的钌基催化剂，使用原位制备技术。与传统的非原位促进方法制备的催化剂相比，采用这种新技术制备的催化剂的活性高出 10 倍。原位促进的催化剂还具有较小的表观活化能并且对H ₂中毒不太敏感。我们系统地研究了原位投加 Cs 的促进作用，并提出了一个由广泛的密度泛函理论计算支持的详细模型，以解释原位和传统非原位制备催化剂的促进作用之间的差异。