CAJ | 학술논문

固定铜铁的总质量不变,采用共浸渍法制备铜铁双金属催化剂.为了更好地了解催化剂的性质,分别用N2吸附-脱附、H2-程序升温还原(H2-TPR)、NH3-程序升温脱附(NH3-TPD)、X射线衍射(XRD)和X射线光电子能谱(XPS)方法对制备的催化剂进行表征.研究发现在100000 h-1空速下,铜铁双金属催化剂呈现出好的活性和氮气选择性.在低温区,随着铜含量的增加,活性和氮气的选择性增加,然而在高温区氮气的选择性直接和铁的含量相关.其中催化剂Fe0.25Cu0.75/ZSM-5,在350° C氨的转化率达到最高,在300° C氮气的选择性上升到97%. Fe0.75Cu0.25/ZSM-5在500°C有很高的氮气选择性甚至可以达到98%.并且所有的催化剂均产生很少的N2O副产物.表征结果显示催化剂的酸量和铜物种的含量可以影响催化剂的活性,并且高的还原能力和铁含量有助于高温氮气选择性的提高.
고정동철적총질량불변,채용공침지법제비동철쌍금속최화제.위료경호지료해최화제적성질,분별용N2흡부-탈부、H2-정서승온환원(H2-TPR)、NH3-정서승온탈부(NH3-TPD)、X사선연사(XRD)화X사선광전자능보(XPS)방법대제비적최화제진행표정.연구발현재100000 h-1공속하,동철쌍금속최화제정현출호적활성화담기선택성.재저온구,수착동함량적증가,활성화담기적선택성증가,연이재고온구담기적선택성직접화철적함량상관.기중최화제Fe0.25Cu0.75/ZSM-5,재350° C안적전화솔체도최고,재300° C담기적선택성상승도97%. Fe0.75Cu0.25/ZSM-5재500°C유흔고적담기선택성심지가이체도98%.병차소유적최화제균산생흔소적N2O부산물.표정결과현시최화제적산량화동물충적함량가이영향최화제적활성,병차고적환원능력화철함량유조우고온담기선택성적제고.
Iron and copper bimetal ic catalysts with fixed total contents of copper and iron were prepared by a co-impregnation method, and then used for selective catalytic oxidation of ammonia to nitrogen. The properties of the catalysts were characterized by N2 adsorption-desorption, H2 temperature-programmed reduction (H2-TPR), NH3 temperature-programmed desorption (NH3-TPD), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The iron and copper bimetal ic catalysts exhibited good activity and high selectivity of N2 at the gas hourly space velocity (GHSV) of 100000 h-1. The activity and N2 selectivity in the low temperature range increased with increasing Cu loading, whereas in the high temperature range (above 400 ° C) the selectivity of N2 was directly related to the content of iron. The highest NH3 conversion was achieved at about 350 °C for Fe0.25Cu0.75/ZSM-5, and the N2 selectivity was up to 97%at 300 °C. On the other hand, the extremely high N2 selectivity about 98%was obtained over Fe0.75Cu0.25/ZSM-5 at 500 °C. In addition, N2O as the by-product and greenhouse gas was obtained in very low amounts for al the catalysts. The characterization results showed that the activity was influenced by the acid content and the amounts of copper species. Moreover, the highly reducing capacity could improve the N2 selectivity.