Sun Yuqi, Liu Wei, Tian Miao, Wang Liguo, Wang Zhongpeng
School of Water Conservancy and Environment, University of Jinan Jinan 250022 China
RSC Adv. 2018 Nov 23;8(68):39197-39202. doi: 10.1039/c8ra07278g. eCollection 2018 Nov 16.
Pretreatment is very important for altering the catalytic properties of the supported noble metal catalysts in many heterogeneous reactions. In this study, a simple and mild pretreatment with N has been reported to re-activate the Au-CeO catalysts that were prepared by a deposition-precipitation method followed by calcination at 600 °C. Upon N pretreatment at 200 °C, the metal-support interaction between Au nanoparticles (NPs) and CeO was observed with the evidence of particular coverage of Au nanoparticles by CeO, electronic interactions and changes in CO adsorption ability. As a result, the CO oxidation activity of the pretreated Au-CeO catalysts largely improved compared with those without any pretreatment and even with those subjected to H and O pretreatments. N pretreatment also makes the Au NPs more resistant to sintering at high temperature. Furthermore, this mild pretreatment strategy can provide a potential approach to improve the thermal stability of other supported noble metal catalysts.
预处理对于改变负载型贵金属催化剂在许多多相反应中的催化性能非常重要。在本研究中，据报道一种简单温和的氮气预处理方法可使通过沉积沉淀法制备并在600℃煅烧的金-二氧化铈催化剂重新活化。在200℃进行氮气预处理后，观察到金纳米颗粒（NPs）与二氧化铈之间的金属-载体相互作用，证据是二氧化铈对金纳米颗粒的特定覆盖、电子相互作用以及一氧化碳吸附能力的变化。结果，与未进行任何预处理的催化剂相比，甚至与经过氢气和氧气预处理的催化剂相比，预处理后的金-二氧化铈催化剂的一氧化碳氧化活性有了很大提高。氮气预处理还使金纳米颗粒在高温下更耐烧结。此外，这种温和的预处理策略可为提高其他负载型贵金属催化剂的热稳定性提供一种潜在方法。
