化对NH3在Ru集群上的第一个N-H键激活的支持效应
Li Zhao1, Huimin Zhuang2, Yixuan Zhang1
1College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao 266580, China.
化 (BN) 支持通过降低激活能障碍,增强氨 (NH3) N-H 键在 (Ru) 集群上的激活. 这种催化支效应在更高的温度和单个Ru原子时更加明显.
科学领域:
- 不同质的催化剂.
- 表面科学是一门学科.
- 计算化学计算化学
背景情况:
- 催化支在异质催化中的作用至关重要,但往往不完全理解.
- 调查支效应提供了关于催化剂设计和反应机制的见解.
研究的目的:
- 阐明一个模型化 (BN) 支对氨 (NH3) 在小型 (Ru) 金属集群 (Ru_n,n=1-3) 上的 N-H 键激活的影响.
- 用密度函数理论 (DFT) 来计算确定BN支持对反应能量和动力学的影响.
主要方法:
- 使用了系统密度函数理论 (DFT) 的计算.
- 对中间体和过渡状态进行了几何优化和能量计算.
- 分析重点是NH3在BN支持的Ru集群上N-H债券激活的第一步.
主要成果:
- 在最有利的路径中,BN支持极小地改变了中间体和过渡状态的平衡结构.
- 支持BN显著降低了激活自由能量 (ΔG≠),从而增加了反应速率.
- 与较低温度 (298 K) 相比,在较高的温度 (673 K) 中,速度提升更为显著.
- 对单个Ru原子 (Ru1) 观察到最明显的支持效应.
- 在N-H债券激活过程中,BN支持可能影响了旋转过渡行为.
结论:
- 该研究提供了对异质催化剂的支持效应的更深入的了解,特别是对于支持的Ru催化剂上的NH3激活.
- 这些发现可以将其推广到其他支持的过渡金属催化剂上,突出显示了支持金属相互作用的重要性.
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