CoMoS_(x)/CeO_(2)-γ-Al_(2)O_(3)催化剂的制备及其催化还原SO_(2)的性能

CoMoS_(x)/CeO_(2)-γ-Al_(2)O_(3)Catalyst:Preparation and Performance in Catalytic Reduction of SO_(2)

采用等容浸渍法引入少量CeO_(2)助剂制备了CoMoS_(x)/CeO_(2)-γ-Al_(2)O_(3)催化剂。通过X射线衍射(XRD)、高角环形暗场像-扫描催化剂的形貌结构、还原性、吸附性能及反应过程等进行了表征,利用固定床反应器研究了其催化CO还原SO_(2)的催化性能及稳定性。结果表明:少量CeO_(2)的引入可以降低反应温度,随着CeO_(2)含量的增加,CoMoS_(x)/CeO_(2)-γ-Al_(2)O_(3)催化剂的催化活性先增剂具有优异的稳定性;等容浸渍法制备的催化剂表面的金属元素分散良好;CeO_(2)的引入提高了催化剂的硫化程度和低温还原进行。

CoMoS_(x)/CeO_(2)-y-Al_(2)O_(3)catalyst was prepared by introducing a small amount of CeO_(2)by isovolume impregnation method.The morphology,reducibility,adsorotion properties and reaction process of the catalysts were characterized by X-ray diffraction(XRD),high-angle annular dark field-scanning transmission electron microscopy(HAADF-STEM),X-ray photoelectron spectroscopy(XPS),temperature programmed desorotion/temperature programmed reduction/temperature programmed surface reaction(TPD/TPR/TPSR).And the catalytic performance and stability of the catalyst for CO reduction of SO_(2)were studied using a fixed bed reactor.The results show that the introduction of a small amount of CeO_(2)can reduce the reaction temperature.With the increase of CeO_(2)content,the catalytic activity of CoMoS_(x)/CeO_(2)-γ-Al_(2)O_(3)catalyst first increased and then decreased.The catalyst with 1.5%molar fraction of CeO_(2)had the best catalytic activity.At the optimal reaction temperature of 350℃,SO_(2)was almost completely converted to S,and the catalyst had excellent stability at 300℃.The metal elements on the surface of the catalyst prepared by the isovolume impregnation method were well dispersed;the introduction of CeO_(2)improved the sulfidation degree and low-temperature reducibility of the catalyst,and increased the adsorption of SO_(2)on the catalyst surface;COS reduced the catalyst at a lower temperature,making the reaction proceed according to the synergistic mechanism of COS and oxygen vacancies.