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用XPS和XAES(X光激发歇电子能谱)研究了Pt/ZnO催化剂的金属与担体间的相互作用。X射线照射、真空加热、尤其是不同温度下的H_2处理都能不同程度地使 ZnO还原,而担载Pt原子簇的存在明显地促进了ZnO的还原;实验结果表明:由H_2处理引起的Pt与ZnO间的相互作用在较宽温度范围内经历两个不同的阶段:低温氢处理(室温和 150℃)使Pt4f电子结合能产生负化学位移,表明电荷从部分还原的担体转移给了担载的金属Pt原子;而高温(300℃)则引起担载金属与担体间界面原子重排,只有经过400℃空气氧化才会破坏这种作用,使体系恢复到初始状态。
The interaction between metal and support of Pt / ZnO catalyst was investigated by XPS and XAES (X-ray photoelectron spectroscopy). X-ray irradiation and vacuum heating, especially H 2 treatment at different temperatures, can all reduce ZnO to some extent. However, the presence of Pt clusters promotes the reduction of ZnO significantly. The experimental results show that the Pt The interaction with ZnO goes through two distinct phases over a wide temperature range: low temperature hydrogen treatment (room temperature and 150 ° C) produces a negative chemical shift of the Pt4f electron binding energy, indicating the transfer of charge from the partially reduced support to the support Of the metal Pt atoms; and high temperature (300 ℃) is caused by the bearing metal and the interface between the rearrangement of the carrier body, only after 400 ℃ air oxidation will destroy this effect, the system returned to its original state.