Zang Yijing, Cai Jun, Han Yong, Wu Huanyang, Zhu Wen, Shi Shucheng, Zhang Hui, Ran Yihua, Yang Fan, Ye Mao, Yang Bo, Li Yimin, Liu Zhi
State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
J Phys Chem Lett. 2023 May 18;14(19):4381-4387. doi: 10.1021/acs.jpclett.3c00790. Epub 2023 May 4.
The structure sensitivity of CO activation in the presence of H has been identified by ambient-pressure X-ray photoelectron spectroscopy (APXPS) on Ni(111) and Ni(110) surfaces under identical reaction conditions. Based on the APXPS results and computer simulations, we propose that, around room temperature, the hydrogen-assisted activation of CO is the major reaction path on Ni(111), while the redox pathway of CO prevails on Ni(110). With increasing temperature, the two activation pathways are activated in parallel. While the Ni(111) surface is fully reduced to the metallic state at elevated temperatures, two stable Ni oxide species can be observed on Ni(110). Turnover frequency measurements indicate that the low-coordinated sites on Ni(110) promote the activity and selectivity of CO hydrogenation to methane. Our findings provide insights into the role of low-coordinated Ni sites in nanoparticle catalysts for CO methanation.
在相同反应条件下，通过常压X射线光电子能谱（APXPS）对Ni(111)和Ni(110)表面进行研究，确定了H存在时CO活化的结构敏感性。基于APXPS结果和计算机模拟，我们提出，在室温附近，CO的氢辅助活化是Ni(111)上的主要反应路径，而CO的氧化还原途径在Ni(110)上占主导地位。随着温度升高，两种活化途径同时被激活。虽然在高温下Ni(111)表面完全还原为金属态，但在Ni(110)上可以观察到两种稳定的Ni氧化物物种。周转频率测量表明，Ni(110)上低配位位点促进了CO加氢生成甲烷的活性和选择性。我们的研究结果为低配位Ni位点在用于CO甲烷化的纳米颗粒催化剂中的作用提供了见解。
