在环境压力下对Cu{100}和Cu{111}的二氧化碳吸附和形态变化
Baran Eren, Robert S Weatherup, Nikos Liakakos
1Department of Chemistry, University of California , Berkeley, California 94720, United States.
Journal of the American Chemical Society
|June 10, 2016
概括
铜催化剂表面对二氧化碳 (CO2) 分离的反应性不同. 100) 表面更活跃,但通过氧气自我中毒限制了二氧化碳吸附,解释了工业甲醇合成中需要的二氧化碳.
科学领域:
- 表面科学
- 催化剂
- 材料化学
背景情况:
- 了解二氧化碳 (CO2) 在金属催化剂上的吸附和解离对于开发高效的催化过程至关重要.
- 铜催化剂广泛用于工业应用,包括从二氧化碳合成甲醇.
- 表面结构和反应条件在二氧化碳激活中的作用仍然是一个活跃的研究领域.
研究的目的:
- 在二氧化碳吸附和解离过程中研究Cu100和Cu111表面的结构和化学成分.
- 阐明二氧化碳解离的机制,并确定影响催化剂活性和稳定性的因素.
- 提供关于二氧化碳转化反应中观察到的自我中毒效应的见解.
主要方法:
- 使用环境压力X射线光电子光谱 (APXPS) 来分析表面化学.
- 使用高压扫描道显微镜 (HPSTM) 探测表面结构和形态.
- 在不同的二氧化碳压力下研究的模型Cu100和Cu111) 催化剂表面.
主要成果:
- 与Cu111表面相比,Cu100表面显示出较高的二氧化碳解离活性.
- 发现二氧化碳解离的产物原子氧会毒害催化剂表面,抑制进一步的二氧化碳吸附.
- HPSTM 发现Cu(100) 表面在 20 Torr 或更高的 CO2 压力下经历纳米聚合,形成活跃的步骤和扭曲点,由预先吸收的氧气抑制.
结论:
- 在铜表面观察到的原子氧自毒机制解释了为甲醇生产添加CO的工业原料的必要性.
- 在二氧化碳下将表面重组为Cu 100) 的纳米集群,通过创建更具反应性的位点来增强催化活性.
- 控制表面的氧气覆盖对于优化二氧化碳解离和铜的催化性能至关重要.
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