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以Si O2为载体,结合浸渍法和程序升温还原法制备磷化镍催化剂,考察了不同n(Ni)/n(P)和不同Ni负载量等对催化剂的结构及异丁烷脱氢性能的影响。运用透射电镜(TEM),X射线衍射(XRD),程序升温还原(H2-TPR),氢气程序升温脱附(H2-TPD)等表征手段考察催化剂的组成与结构、还原性能及氢吸附性能。研究结果表明:Ni/P比对催化剂表面的物相有较大影响,n(Ni)/n(P)为1.0和0.5时,形成Ni2P相;n(Ni)/n(P)为1.5时,形成Ni12P5。随着Ni负载量的增加,活性组分Ni2P粒子尺寸变大,但分散度降低。磷化镍能够催化异丁烷脱氢制异丁烯,但Ni2P的催化活性要比Ni12P5高,经实验研究发现,当Ni/P比为1.0、负载量为10%、n(H2)/n(i-C4H10)=1.0、空速为800 h-1时,在460℃反应时,对异丁烯的选择性可达到80%。
Nickel phosphide catalysts were prepared by impregnation method and temperature programmed reduction method using Si O2 as carrier, and the effects of different n (Ni) / n (P) and Ni loadings on the structure and isobutane dehydrogenation influences. The composition and structure, reduction performance and hydrogen adsorption performance of the catalyst were investigated by means of TEM, X-ray diffraction (XRD), temperature-programmed reduction (H2-TPR) and hydrogen-temperature programmed desorption (H2-TPD) The results show that the Ni / P ratio has a significant effect on the phase of the catalyst, Ni2P phase is formed when n (Ni) / n (P) is 1.0 and 0.5; , Forming Ni12P5. With the increase of Ni loading, the size of Ni2P particles increased, but the dispersibility decreased. Nickel phosphide can catalyze the dehydrogenation of isobutane to isobutylene, but the catalytic activity of Ni2P is higher than that of Ni12P5. The experimental results show that when the Ni / P ratio is 1.0 and the loading is 10%, n (H2) / n (i -C4H10) = 1.0, and the space velocity is 800 h-1, the selectivity to isobutylene can reach 80% at 460 ℃.