老化时间对Cu/ZnO/Al2O3合成甲醇催化剂性能的影响
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摘要: 并流共沉淀法制备了CuO/ZnO/Al2O3催化剂前驱体及催化剂,用XRD、TG-DTG、TPR、N2吸附及加压微反活性评价技术,考察了母料老化时间对催化剂前驱体物相组成及焙烧后物料中CuO-ZnO间的作用和物化性能的影响,提出了催化剂母料物相随老化时间的变化。研究表明,老化时间对催化剂活性的影响是通过改变催化剂比表面积及形成CuOZnO固溶体的结果。
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关键词:
- CuO/ZnO/Al2O3催化剂 /
- 合成甲醇 /
- 前驱体 /
- 老化时间
Abstract: The aging process of copperzincaluminum precursors was studied by XRD, TGDTG and TPR techniques. The catalytic activity of CuO/ZnO/Al2O3 catalyst for methanol synthesis were tested using continues flow type fixedbed reactor. For the precursors prepared at the precipitating condition of pH=8.0 and temperature=80℃, the initial phases of the precipitate was a mixture of copper nitrate hydroxide Cu2(OH)3NO3, georgeite(amorphous Cu2CO3(OH)2) and hydrozincite Zn5 (CO3)2(OH)6. By increasing duration of its aging time, the phase of Cu2(OH)3 NO3first transited to georgeite, then interdiffused with Zn5(CO3)2(OH)6, resulting in two new phases: rosasite (Cu,Zn)2CO3(OH)2 and aurichalcite (Cu,Zn)5(CO3)2(OH)6. It was found that the composition and structure of the precursors altered obviously after the colour transition point. The research results demonstrate that the BET surface area and the amounts of CuOZnO solidsolution of the catalyst increased as the aging time extending which in turn to influence the catalytic activity of the catalyst.-
Key words:
- Cu/ZnO/Al2O3catalyst /
- methanol synthesis /
- precursors /
- ageing time
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