硫酸负载对Pt/SO_(4)^(2-)-(ZrO_(2)-Al_(2)O_(3))催化剂性能的影响

Effect of sulfuric acid loading on the properties of Pt/SO_(4)^(2-)-(ZrO_(2)-Al_(2)O_(3))

采用共沉淀-浸渍法制备了系列硫酸负载催化剂Pt/SO_(4)^(2-)-(ZrO_(2)-Al_(2)O_(3)),利用X射线衍射仪、物理吸附仪、红外光谱仪等对其进行了表征,并在固定床微型反应装置上对其催化异丁烷正构化反应性能进行了评价。结果表明:硫酸单层分散于载体表面,硫酸负载不利于四方晶相ZrO_(2)长大;随着硫酸负载量的增加,催化剂介孔结构的有序性增强且孔径减小,孔径最小降为3.41 nm,孔容可提高至0.091 cm^(3)/g,比表面积增至100 m^(2)/g以上;在反应温度为250℃的条件下,硫酸负载量为15%时,异丁烷转化率高达41.74%;硫酸负载量为2%时,正丁烷选择性最高为93.91%。

A series of Pt/SO_(4)^(2-)-(ZrO_(2)-Al_(2)O_(3))catalysts with different sulfur contents were prepared by precipitation-impregnation method and characterized by X-ray diffraction instrument,physical adsorption instrument,and infrared spectrometer.The catalysts were evaluated for isobutane isomerization reaction using a fixed bed reactor.The results showed that the sulfate species were chemically monolayer dispersed on the carrier surface and inhibited the growth of the tetragonal phase ZrO_(2).With the increase of sulfuric acid loading,the mesoporous structure became more ordered and the pore size decreased.The minimum pore size decreased to 3.41 nm,while the pore volume increased to 0.091 cm^(3)/g and the specific surface area increased to higher than 100 m^(2)/g.Under the condition of reaction temperature 250℃,the isobutane conversion reached 41.74%when 15%of sulfuric acid was loaded,the maximum selectivity to n-butane(93.91%)was obtained when the sulfuric acid loading was 2%.