摘要
碱性体系中以水玻璃和硅溶胶为双硅源,硫酸铝为铝源,在硅铝酸盐凝胶形成过程中加入氧氯化锆,用水热晶化法成功合成了Zr-ZSM-5分子筛。通过XRD、Raman、UV-VIS、BET、SEM、NH3-TPD、Py-IR等手段对其进行表征。研究结果表明:Zr成功进入ZSM-5分子筛骨架,且随着锆摩尔含量的增加,分子筛的比表面积减小,孔径和孔体积增大,势必会影响到分子筛的择形催化性能;此外,分子筛的酸类型重新分布,L酸比例增大,总酸量和酸强度有所减小,势必会影响其酸催化性能;同时分子筛的生长方式也发生了改变,晶体结构由三维棺状变为二维层片状,相对结晶度有所降低,但其骨架结构依然保持完整。
Under basic conditions, Zr-ZSM-5 molecular sieve with the MFI structure were successfully prepared adopting hydrothermal synthesis method using sodium silicate and ludox as double silica source, aluminium sulfate as alumina source and zirconium oxychloride as zirconia source. It was characterized by XRD, Raman, UV-Vis, BET, SEM, NH3-TPD, Py-IR. The results showed that Zr successfully entered the ZSM-5 molecular sieve framework and the specific surface area of molecular sieve decreased, pore size and pore volume increased with increase of the molar concentration of zirconium, which is bound to affect the shape selective catalytic performance of molecular sieve; In addition, acid type redistributed, Lewis acid ratio increased, total acidity and acid strength reduced , which are bound to influence the acid catalytic performance; The growth way of ZSM-5 molecular sieve changed from ＂coffined＂ shape to layer, the relative crystallinity decreased gradually, but framework was kept perfectly.
基金
国家自然科学基金重点项目(21306072)
关键词
双硅源
水热晶化
Zr-ZSM-5
催化性能
double silica source
hydrothermal synthesis
Zr-ZSM-5
characterization
