Surface silanol structures, acid properties, and tungsten dispersion of the sol-gel-derived 7W/SiO₂–xAl₂O₃ (x = 0.2–23 wt%) were investigated by means of ²⁹Si, ²⁷Al, and ¹H MAS NMR, NH₃-TPD, in-situ NH₃-IR spectroscopy, XRD, and Raman spectroscopy. The surface silanol structure changed upon Al and tungsten loadings; however, loading of 1 wt% Al₂O₃ appeared to be the threshold for preserving the Si(OH)Al with isolated bridge after impregnation of 7 wt% W. The 7W/SiO₂–1Al₂O₃ (1 wt% Al₂O₃) was also found to exhibit the lowest ratio of Bronsted to Lewis acid with the highest amount of Lewis acid sites and the best catalyst performances in propene self-metathesis at 550 °C in terms of both propene conversion and ethylene/butene selectivity. Despite its low tungsten dispersion, the metathesis activity was correlated well with the higher amount of tungsten carbene species, which were formed on the catalysts containing higher isolated bridge silanol and the presence of higher Lewis acid sites.

通过²⁹ Si、²⁷ Al 和¹ H MAS研究了溶胶-凝胶衍生的 7W/SiO ₂ –xAl ₂ O ₃ (x = 0.2–23 wt%) 的表面硅烷醇结构、酸性质和钨分散NMR、NH ₃ -TPD、原位NH ₃ -IR光谱、XRD和拉曼光谱。表面硅烷醇结构随着铝和钨的加入而改变；然而，负载 1 wt% Al ₂ O ₃似乎是在浸渍 7 wt% W 后保留具有隔离桥的 Si(OH)Al 的阈值。7W /SiO ₂ –1Al ₂ O ₃还发现(1 wt% Al ₂ O ₃ ) 表现出最低的布朗斯台德酸与路易斯酸的比率，具有最高数量的路易斯酸位点和在 550 °C 的丙烯自复分解反应中在丙烯转化率方面的最佳催化剂性能和乙烯/丁烯选择性。尽管钨的分散性较低，但复分解活性与较高量的钨卡宾物种密切相关，后者是在含有较高分离桥硅烷醇和较高路易斯酸位点的催化剂上形成的。