用于CH_4/CO_2重整反应Ni/ZrO_2-Al_2O_3催化剂的结构和抗积炭性能

Structure and Anti-carbon Capacity of ZrO_2-Al_2O_3 Mixed Oxides in Ni-Based Catalyst for CH_4/CO_2 Reforming

在表面活性剂P123作用下,通过无机盐的双水解反应制备了介孔ZrO2-Al2O3复合氧化物.研究发现,所得样品具有较大的比表面积和可调变的孔结构.ZrO2可嵌入到Al2O3骨架中形成固溶体,因而热稳定性增加;与Al2O3相比,适量ZrO2加入使ZrO2-Al2O3的酸密度和酸强度增加.在CH4/CO2干气重整反应中,Ni/ZrO2-Al2O3催化剂活性略低于Ni/Al2O3,但表现出优良的抗积炭性能.这不仅与Ni分散度有关,而且与因氧化物载体缺陷位和小晶粒而造成的电子效应密切相关.

In the presence of P123 surfactant,mesoporous ZrO2-Al2O3 mixed oxides were prepared using inorganic salts as precursors by a bihydrolysis route.The results showed that the mixed oxides bear high surface area and controlling pore structure.Some solid solution can be formed through the incorporation of zirconium to the alumina framework.The introduction of a proper amount of zirconia to alumina increased the acid sites number and acidic strength of the mixed oxides as compared with pure alumina.Methane reforming with CO2 was used to detect the activity and stability of the Ni-based catalysts.The Ni/ZrO2-Al2O3 catalysts exhibit higher anti-carbon capacity than Ni/Al2O3,but possess slightly low activity.The improvement of anti-carbon capacity is ascribed to the dispersion of the active component and support effect induced by deficiencies and fine crystal size of the support.