Co-Mn复合氧化物/SBA-15的制备与催化氧化性能

Preparation and Catalytic Oxidation Performance of Co-Mn Composite Oxide/SBA-15

为提高苯甲醇氧化为苯甲醛的选择性,先以水热法制备模板介孔SBA-15,再以纳米浇铸法引入前驱体硝酸钴和硝酸锰,制备Co-Mn复合氧化物/SBA-15(Co-Mn/SBA-15)催化剂.通过扫描电镜、X射线衍射仪、X射线光电子能谱仪等设备,探究Co-Mn/SBA-15的结构,并研究Co-Mn/SBA-15对苯甲醇的选择氧化性.XRD结果表明,金属硝酸盐以MnCo_(2)O_(4)晶体存在于模板分子筛上,而模板分子筛并未形成晶体,仍以无定型二氧化硅存在.XPS结果表明,负载复合金属氧化物后,Si的价态不发生改变,在复合金属氧化物中,Co存在2种价态,分别为Co^(3+)和Co^(2+),其中少部分Co^(2+)以X射线卫星峰的形式存在.^(1)HNMR结果表明,Co-Mn/SBA-15催化剂对苯甲醇的催化选择率为9.32%.

In order to improve the selectivity oxidation of benzyl alcohol to benzaldehyde,mesoporous SBA-15 was prepared by hydrothermal method.The composite oxide/SBA-15(Co-Mn/SBA-15)catalyst was then prepared by introducing precursor cobalt nitrate and manganese nitrate by nano-casting.The structure of supported metal oxide catalyst was investigated by scanning electron microscope,X-ray diffraction and X-ray photoelectron spectroscopy,and the selective oxidation of Co-Mn/SBA-15 to benzyl alcohol was also studied.XRD results show that the metal nitrate exists in the form of MnCo_(2)O_(4) crystals on the template molecular while the template molecular still exists in amorphous silica form.XPS results demonstrate that the valence state of Si does not change after loading composite metal oxides.There are two valence states of Co,namely Co^(3+) and CO^(2+),among which a small amount of Co^(2+) exist in the form of X-ray satellite peaks.^(1)HNMR results show that the selectivity of the catalyst to benzyl alcohol is 9.32%.