机器学习和实验揭示了PdAg催化剂的表面结构及其对乙烯半化的影响
Xiao-Tian Li1, Lin Chen1, Cheng Shang1
1Collaborative Innovation Center of Chemistry for Energy Material, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Key Laboratory of Computational Physical Science, Department of Chemistry, Fudan University, Shanghai 200433, China.
这项研究结合了机器学习和实验,以改进选择性化合金 (PdAg) 催化剂. 在二氧化 (TiO2) 支持的PdAg催化剂在高转化率下达到85%的选择性,优于以前的催化剂.
科学领域:
- 不同质的催化
- 材料科学
- 计算化学
背景情况:
- 银合金 (PdAg) 是在乙烯存在时选择性化的关键工业催化剂.
- 提高催化剂的选择性和性能,特别是在低温下,仍然是乙烯化的一个重大挑战.
- 在反应条件下了解PdAg合金的动态表面结构是催化剂设计的关键.
研究的目的:
- 使用机器学习和实验催化剂的组合,在反应条件下阐明PdAg合金催化剂的表面状态.
- 确定最佳的PdAg组合和结构,以提高乙烯化中的选择性和稳定性.
- 为下一代PdAg催化剂的合理设计提供基本见解.
主要方法:
- 基于机器学习的原子模拟来探索全球潜在能量表面.
- 在反应条件下确定Pd-Ag-H体积和表面相位图.
- 试验验证使用基TiO2支持的Pd1Ag3催化剂的催化剂性能.
主要成果:
- 确定了两个关键的散装成分:Pd1Ag1 (R3̅m) 和Pd1Ag3 (Pm3̅m).
- 在反应条件下具有不同Pd:Ag比率的量化表面结构.
- 证明催化剂活性取决于 (111) 表面的 PdAg 模式,而选择性则取决于 (100) 表面的 Pd 暴露.
- 在100小时的乙烯转化>96%的过程中,通过支持rutile-TiO2的Pd1Ag3催化剂实现了85%的选择性.
结论:
- 该研究澄清了PdAg合金的表面动态,揭示了不同的结构性能关系.
- 基于鲁-TiO2的Pd1Ag3组合表现出选择性乙烯化的优异性能.
- 合理的催化剂设计策略包括控制Pd:Ag比率,最小化纳米粒子大小,并利用活性支来控制面暴露.
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