Silica beta synthesized under alkaline conditions
Silica beta synthesized under alkaline conditions
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DOI：
10.1016/j.micromeso.2018.02.049
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发表时间：
2018-08
影响因子：
5.2
通讯作者：
Baorong Wang;Min Lin;Jianming Yang;Xinxin Peng;Bin Zhu;Yao Zhang;Changjiu Xia;W. Liao
中科院分区：
文献类型：
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作者：
Baorong Wang;Min Lin;Jianming Yang;Xinxin Peng;Bin Zhu;Yao Zhang;Changjiu Xia;W. Liao
β沸石是一种重要的催化材料，但硅铝摩尔比超过200的材料很难合成。通常，纯二氧化硅 β 和杂原子沸石 β 是在接近中性 pH 值下使用 HF 作为矿化剂制备的。但HF具有剧毒和腐蚀性，形成的沸石通常大于10μm。本文采用碱性盐和含氟盐，由碱性前驱体水热合成纯二氧化硅β。前驱体中的二氧化硅源和碱金属阳离子会影响结晶过程，优选原硅酸四乙酯和钠阳离子。纯二氧化硅β为片状，第三天形成的晶体约为50×300×300nm，并随时间不断增长，一周后合成了尺寸均匀的约200×700×700nm的纯二氧化硅β沸石。更重要的是，纯二氧化硅β没有缺陷，并且具有高度疏水性。
Zeolite β is an important material in catalysis, however the material with molar ration of silicon and aluminum more than 200 is difficult to synthesize. Typically, the pure silica β and heteroatom zeolite β are prepared at near neutral pH using HF as the mineralization agent. However, the HF is highly toxic and corrosive, and the zeolites formed are usually more than 10 μm. In this paper, alkaline and fluorine-containing salts was applied, and pure silica β was hydrothermally synthesized from a basic precursor. The silica resource and alkali metal cations in the precursor would influence the crystallization process, tetraethyl orthosilicate and sodium cations are preferred. The pure silica β is plate-like, the crystals formed on the third day are about 50 × 300 × 300 nm, which keep growing with the time, and pure silica zeolite β with uniform size of about 200 × 700 × 700 nm are synthesized in a week. More importantly, the pure silica β is defects-free, and it's highly hydrophobic.