Ni/Ce_(θ)M_(1-θ)O_(x)催化剂催化二苯并呋喃加氢脱氧性能研究

Study on hydrodeoxygenation performance of dibenzofuran by Ni/Ce_(θ)M_(1-θ)O_(x)catalysts

中低温煤焦油中杂原子氧的含量较高,会造成油品热值低和稳定性差的问题,而加氢脱氧是煤焦油加氢精制最有效的方法之一。采用水热法制备了掺杂金属离子的CeO_(2)的Ni/Ce_(θ)M_(1-θ)O_(x)催化剂(M=Fe,Ga,Zr),研究了催化剂表面氧空位相对含量对二苯并呋喃加氢脱氧反应的影响。采用透射电子显微镜(TEM)、X-射线衍射(XRD)对催化剂形貌和结构进行了分析,采用拉曼光谱和X射线光电子能谱(XPS)对催化剂表面氧空位进行了研究。利用高压反应釜对具有不同氧空位相对含量的Ni/Ce_(θ)M_(1-θ)O_(x)催化剂上二苯并呋喃的加氢脱氧活性进行了评价。结果表明,CeO_(2)掺杂Ga、Zr和Fe后,Ga、Zr和Fe进入CeO_(2)晶格形成了固溶体结构,导致CeO_(2)晶格畸变,促进了催化剂表面氧空位的产生。其中,Ni/CeθFe1-θOx催化剂的氧空位相对含量最高,具备最高的脱氧活性。反应180 min时,Ni/CeθFe1-θOx催化剂的含氧中间产物的选择性降低至40.03%,脱氧产物的选择性增加至59.81%,说明催化剂表面氧空位相对含量增多有利于提高其活性。

The high content of heteroatomic oxygen in medium-low temperature coal tar can cause the problems of low calorific value and poor oil stability.Hydrodeoxygenation is one of the most effective methods for coal tar hydrodeoxygenation.Ni/Ce_(θ)M_(1-θ)O_(x)catalysts(M=Fe,Ga,Zr)doped with metal ions of CeO_(2)were prepared by hydrothermal method.The effect of the relative content of oxygen vacancies of catalysts on hydrodeoxygenation of the dibenzofuran was studied.The morphology and structure of catalysts were characterized by transmission electron microscope(TEM)and X-ray diffraction(XRD),and the oxygen vacancies on the catalyst surface were studied by Raman spectroscopy and X-ray photoelectron spectroscopy(XPS).The hydrodeoxygenation performance of dibenzofuran of Ni/Ce_(θ)M_(1-θ)O_(x)catalysts with different amounts of oxygen vacancies was evaluated in a high-pressure reactor.The results show that after doping Ga,Zr and Fe with CeO_(2),Ga,Zr and Fe enter the CeO_(2)lattice to form a solid solution structure,which leads to the distortion of CeO_(2)lattice and promotes the formation of oxygen vacancies.Ni/CeθFe1-θOx catalysts have the highest relative content of oxygen vacancies and the highest deoxygenation activity.After reaction for 180 min,the selectivity of oxygen-containing intermediates on Ni/CeθFe1-θOx catalysts reduces to 40.03%and the selectivity of deoxygenation products increases to 59.81%,indicating that the relative content of oxygen vacancies of catalysts improves their activity.