在NO + H反应中 γ-Al2O3(110) 的催化活性:一项DFT研究
1Boreskov Institute of Catalysis, Akademik Lavrentiev Ave 5, Russian Federation. cholach@catalysis.ru.
Physical chemistry chemical physics : PCCP
|September 5, 2023
概括
密度函数理论计算显示,玛 (γ-Al2O3) 催化NO和H2反应. 在 γ-Al2O3 () 上的低协调位点 () 促进NO吸附和H2结合,形成N2或N2O释放的氧胺中间体.
科学领域:
- 表面科学和催化剂的研究
- 计算化学计算化学
- 材料科学 材料科学 材料科学
背景情况:
- 玛 (γ-Al2O3) 是一种广泛使用的催化剂支.
- 了解γ-Al2O3表面与NO和H2等反应性气体的相互作用对于催化应用至关重要.
- 密度函数理论 (DFT) 为研究原子层面表面反应提供了一个强大的工具.
研究的目的:
- 为了研究γ-Al2O3(110) 表面与氧化 (NO) 和 (H2) 的相互作用.
- 使用DFT阐明对g-Al2O3的NO和H2反应的催化路径 (下图) 使用DFT.
- 了解表面位点和中间体在反应机制和潜在抑制中的作用.
主要方法:
- 密度函数理论 (DFT) 的计算被用来建模 γ-Al2O3的表面.
- 计算的重点是吸附能量,结合亲和力和NO和H2的反应途径.
- 研究了共吸附物种和反应条件对催化过程的影响.
主要成果:
- γ-Al2O3(110) 表面吸附NO,并与H原子结合,但会排斥H2分子.
- 确定了一条涉及低协调OII-AlIII-OII位点的催化途径,导致氧胺的形成,随后释放N2或N2O.
- 形成NH3可以抑制主要的反应途径,而过量的O2可以减轻这种抑制. 氧化化物形成受到抑制,但不排除.
结论:
- γ-Al2O3的催化活性是由于特定的低协调位点.
- 反应机制涉及氧胺中间体的形成和转化.
- 表面过程和共吸收物种的存在显著影响反应结果和氧化化物形成的可能性,这表明带隙和催化活性之间存在联系.
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