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以H2O2为氧化剂,分别以传统沉淀法(以氨水为沉淀剂)和碳酸铵水解法制备了CeO2材料。采用傅里叶变换红外(FTIR)、拉曼光谱(Raman)、热重-差示扫描分析(TG-DTA)及X光电子能谱(XPS)等手段对沉淀前躯体及其分解过程进行了研究。结果表明,在碳酸铵水解法制备的前躯体中含有O22-,CO32-和OH-物种,而在水解过程中,碳酸根会逐渐被氢氧根取代。虽然两者方法制备的沉淀的化学成分基本一样,但碳酸铵水解法改变了沉淀颗粒的堆积方式,因此制备的CeO2具有更好的抗高温老化性能和还原性能。经过900℃焙烧3 h后,比表面仍有27 m2·g-1。
Using H2O2 as oxidant, CeO2 material was prepared by the traditional precipitation method (using ammonia water as precipitating agent) and ammonium carbonate hydrolysis method respectively. The precursors and their decomposition processes were studied by Fourier transform infrared (FTIR), Raman spectroscopy, TG-DTA and X-ray photoelectron spectroscopy (XPS) . The results showed that O22-, CO32- and OH- species were formed in the precursors prepared by hydrolysis of ammonium carbonate, and carbonate was gradually replaced by hydroxide during the hydrolysis. Although the chemical compositions of the precipitates prepared by the two methods are basically the same, the hydrolysis of ammonium carbonate changes the deposition mode of the precipitated particles. Therefore, the prepared CeO2 has better anti-aging properties and reducing properties. After calcination at 900 ℃ for 3 h, the specific surface area was still 27 m2 · g-1.