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https://www.sciencedirect.com/science/article/pii/S0926337321000758
•Ultrathin Al2O3 nanosheet was synthesized by a phosphate-assisted dynamic hydrothermal method.
•Al2O3 nanosheet presented superior thermal stability and retained θ phase at 1200 °C.
•An intercalation-swelling-exfoliation pathway accompanied by phosphate induced dissolution-growth was proposed.
•Pd/Al2O3 nanosheet revealed high activity of propane combustion and resistance to sintering.
•Re-dispersion of Pd and SMSI via high-temperature treatment was observed.
Two-dimensional γ-Al2O3 nanosheet with rich pentacoordinate Al3+ sites which can nicely stabilize noble metals via strong interactions between metal and support has been focused. However, the synthesis of ultrathin and highly thermal-stable Al2O3 is challenging. Herein, we report an effective approach to synthesize ultrathin Al2O3 nanosheets with regular leaf-like architecture as well as high thermal-stability. A novel intercalation-swelling-exfoliation pathway was proposed to elucidate the formation of ultrathin sheet-like structure and then its morphology/thickness could be further adjusted via a dissolution-growth induced by phosphate. Meanwhile, the presence of phosphate further enhanced thermal stability of Al2O3 nanosheets due to the occupation or depletion of high-reactive sites and surface hydroxy groups. Subsequently, the thermally stable γ-Al2O3 nanosheets with moderate anchoring sites was used as a support of Pd and investigated for catalytic combustion of propane. The Pd/Al2O3 nanosheet exhibited a superior catalytic activity for propane combustion and the complete conversion was below 300 °C, more importantly, the outstanding resistance to high temperature (1000 °C) was observed, which was ascribed to the re-dispersion of Pd particles and the occurrence of strong metal-support interaction (SMSI) at high temperature.
特别感谢瞻望成教授的两个学生(吴青青、颜娇榕)的贡献
本文的主要“内容”来源于多年前的一篇文章中参比样品的制备,经过后续进一步发展而成
Qiguang Dai*, Qin Zhu; Yang Lou; Xingyi Wang*, Role of Brønsted Acid Site during Catalytic Combustion of Methane over PdO/ZSM-5: Dominant or Negligible?, Journal of Catalysis, 357, 2018, 29–40.
https://www.sciencedirect.com/science/article/pii/S002195171730355X
多年前,2017,在制备ZSM-5分子筛的对照样品SiO2和Al2O3,按照分子筛的制备方法,得到SiO2样品理所当然是纯Si-ZSM-5,但是对于纯氧化铝样品发现有点特别,表现出纳米片形貌。在文章发表之后,就做了初步的实验,进一步验证了氧化铝纳米片确实能够合成且可以调控,后续申请了专利,也顺利授权。由于平时比较忙也没学生,这个工作就放下了。
后来向詹教授“借”了个学生,把氧化铝纳米片合成的工作捡了起来,经过进一步的完善、扩展(预期后续还能成文两篇小文章),成文为本文:优化制备方法、考察更多细节、探究了合成机理、以及热稳定性方面带来的好处,负载贵金属考察丙烷催化燃烧活性、进一步确认课题组前期发现的贵金属高温再分散现象等等工作
关于本文的一点感想:有很多“成果”来自于意外,实验人的细心程度、洞察力尤为重要,导师经验丰富但如果不在“一线”很多可能有意义的东西都会被无经验的学生白白放过
本人有很多材料的合成都来自意外,后续将逐渐成文(目前至少有4种材料,有时间后都要整理出来)
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