淀粉改性SiO2载体的预处理温度 对其负载的铜基催化剂甲醇转化性能的影响

以淀粉为改性剂制备了淀粉改性的SiO₂载体(SSi),经不同温度(T)焙烧处理后再负载活性铜组分(10%,质量分数),获得一系列铜基催化剂(Cu/SSi-T);采用TG、FT-IR、XRD、H₂-TPR、SEM和氮气吸附等技术对载体和催化剂进行了表征,并考察了其对甲醇低温转化反应催化性能。结果显示,淀粉的存在可以减缓载体表面硅羟基的脱除速度;载体表面硅羟基有利于铜物种的分散,从而提高催化剂的活性。不同预处理温度能调变载体表面硅羟基浓度、比表面积和孔结构,并对催化剂上铜物种的晶粒大小及其催化性能有显著的影响。

Effect of calcination temperature of starch-modified silica on the performance of silica supported Cu catalyst in methanol conversion

A series of starch-modified SiO₂ (SSi-T) were obtained by calcining the extrudate of SiO₂ and starch at different temperatures (T) and used as the support to prepare Cu catalysts (Cu/SSi-T, 10%) by the impregnation method. The Cu catalysts were characterized by N₂ sorption, FT-IR, TG, XRD, SEM and H₂-TPR; their catalytic performance in methanol conversion was investigated in a fixed bed reactor. The results indicated that starch can reduce the removal rate of silanol groups (Si-OH) from the surface of the support during calcination and the surface silanol groups are beneficial to the dispersion of Cu species. The calcination temperature of starch-modified SiO₂ exhibits a significant influence on the surface silanol (Si-OH) concentration, the surface area and porous structure of the support; as a result, it may be used to adjust the size of supported CuO crystal grains and dispersion of Cu species, which determine the performance of the silica supported Cu catalysts in methanol conversion.