负载型无铬超细铁基变换催化剂的制备和催化性能

Preparation and Performance of Supported Cr-Free Ultrafine Iron-Based Catalysts for Water-Gas Shift Reaction

以镁铝尖晶石为载体 ,以过渡金属氧化物为助剂 ,用吸附γ Fe2 O3 胶体法制备了负载型无铬铁基变换催化剂 .TEM ,XRD ,BET和活性测试结果表明 ,采用胶体负载法制备的变换催化剂 ,其活性组分Fe3 O4以分立的超细微颗粒分布在镁铝尖晶石载体表面上 ,颗粒之间存在一定的间隔 .过渡金属氧化物NiO或V2 O5能够进入Fe3 O4晶格形成固溶体 ,起到代替氧化铬的作用 ,提高催化活性 .负载型催化剂FeNi/MgAl2 O4(m(NiO) /m(Fe2 O3) =3% )在汽 /气比为 1和空速为 2 0 0 0h-1的反应条件下 ,CO转化率在 4 0 0和 35 0℃时分别为 95 %和 80 % ;在高空速和低汽 /气比条件下也具有很好的催化性能 .稳定性实验结果表明 ,该催化剂具有良好的热稳定性和一定的抗硫能力 .与非负载型催化剂相比 。

For water gas shift reaction, the supported iron based catalysts promoted by transition metal oxides (NiO, V 2O 5 and CuO) were prepared by adsorbing γ Fe 2O 3 colloid on MgAl 2O 4 spinel and investigated by means of TEM, XRD, BET and catalytic activity measurement. The results showed that Fe 3O 4 is dispersed on the surface of MgAl 2O 4 spinel as discrete ultrafine particles. Therefore the specific surface area of the catalyst and the disperson of Fe 3O 4 can be improved. NiO and V 2O 5 can enter the lattice of Fe 3O 4 and form solid solution, while CuO can be reduced. The orthogonal experiments indicated that the optimal content of Fe 2O 3 and K 2O in the catalyst is 28% and 4%, respectively. Under the conditions of V (steam) / V (gas) =1 and SV= 2?000 h -1 , the CO conversion is 95% at 400 ℃ and 80% at 350 ℃ for catalyst FeNi/MgAl 2O 4( m (NiO) / m (Fe 2O 3) =3%). The catalyst still has high catalytic activity at low V (steam) / V (gas) ratio (0 6) and high space velocity ( 3?000 h -1 ). The catalyst prepared by adsorbing γ Fe 2O 3 colloid on MgAl 2O 4 spinel has superior thermostability and resistance to sulfur poison. It is of great significance for the environment by replacing Cr 2O 3 with transition metal oxide in iron based catalysts while keeping their high catalytic performance.