化工进展
化工進展
화공진전
CHEMICAL INDUSTRY AND ENGINEERING PROGRESS
2015年
3期
738-744,757
,共8页
李静%王乐%孙维周%左志军%黄伟
李靜%王樂%孫維週%左誌軍%黃偉
리정%왕악%손유주%좌지군%황위
甲烷%二氧化碳%Co-Pd/TiO2催化剂%浸渍法%溶胶-凝胶法%制备
甲烷%二氧化碳%Co-Pd/TiO2催化劑%浸漬法%溶膠-凝膠法%製備
갑완%이양화탄%Co-Pd/TiO2최화제%침지법%용효-응효법%제비
methane%carbon dioxide%Co-Pd/TiO2 catalysts%impregnation%sol-gel%preparation
以钴、钯为活性金属,分别采用浸渍法和溶胶-凝胶法制备了Co-Pd/TiO2催化剂,考察了不同制备方法制备的Co-Pd/TiO2催化剂对CH4-CO2梯阶转化直接合成C2含氧化合物的影响。利用XRD、XPS和N2-吸附-脱附对催化剂进行了表征。结果表明:两种方法制备的催化剂反应前与反应后表面织构都存在较大变化,且催化剂中均存在CoTiO3物种,这是活性金属Co与载体TiO2之间发生强相互作用,Co2+替代TiO2晶格中的Ti4+的结果;CoO和金属Pd可能是该反应的活性中心;反应前与反应后溶胶-凝胶法制备的催化剂的表面Co含量均低于浸渍法制备的催化剂,而表面Pd含量则均高于浸渍法制备的催化剂,且溶胶-凝胶法制备的催化剂各种产物的生成速率均高于浸渍法制备的催化剂,因此,与浸渍法制备的催化剂相比,溶胶-凝胶法制备的催化剂具有更好的催化活性。
以鈷、鈀為活性金屬,分彆採用浸漬法和溶膠-凝膠法製備瞭Co-Pd/TiO2催化劑,攷察瞭不同製備方法製備的Co-Pd/TiO2催化劑對CH4-CO2梯階轉化直接閤成C2含氧化閤物的影響。利用XRD、XPS和N2-吸附-脫附對催化劑進行瞭錶徵。結果錶明:兩種方法製備的催化劑反應前與反應後錶麵織構都存在較大變化,且催化劑中均存在CoTiO3物種,這是活性金屬Co與載體TiO2之間髮生彊相互作用,Co2+替代TiO2晶格中的Ti4+的結果;CoO和金屬Pd可能是該反應的活性中心;反應前與反應後溶膠-凝膠法製備的催化劑的錶麵Co含量均低于浸漬法製備的催化劑,而錶麵Pd含量則均高于浸漬法製備的催化劑,且溶膠-凝膠法製備的催化劑各種產物的生成速率均高于浸漬法製備的催化劑,因此,與浸漬法製備的催化劑相比,溶膠-凝膠法製備的催化劑具有更好的催化活性。
이고、파위활성금속,분별채용침지법화용효-응효법제비료Co-Pd/TiO2최화제,고찰료불동제비방법제비적Co-Pd/TiO2최화제대CH4-CO2제계전화직접합성C2함양화합물적영향。이용XRD、XPS화N2-흡부-탈부대최화제진행료표정。결과표명:량충방법제비적최화제반응전여반응후표면직구도존재교대변화,차최화제중균존재CoTiO3물충,저시활성금속Co여재체TiO2지간발생강상호작용,Co2+체대TiO2정격중적Ti4+적결과;CoO화금속Pd가능시해반응적활성중심;반응전여반응후용효-응효법제비적최화제적표면Co함량균저우침지법제비적최화제,이표면Pd함량칙균고우침지법제비적최화제,차용효-응효법제비적최화제각충산물적생성속솔균고우침지법제비적최화제,인차,여침지법제비적최화제상비,용효-응효법제비적최화제구유경호적최화활성。
Co-Pd/TiO2 catalysts are prepared by impregnation and sol-gel methods,separately. The effect of preparation methods on Co-Pd/TiO2 catalyst performance is investigated for the direct synthesis of C2 oxygenates from CH4 and CO2 by a step-wise reaction technology. The as-prepared catalysts are characterized by XRD,XPS and nitrogen adsorption-desorption. The results show that the surface property and texture of both impregnation catalyst and sol-gel catalyst have obvious changes after reaction. The existence of CoTiO3 species in all catalyst samples shows that there is a strong interaction between active metal Co and the carrier TiO2,and that Co2+can substitute Ti4+in the titania lattice. CoO and Pd may act as the active center for this reaction. For both fresh and used catalyst samples,surface Co contents of sol-gel catalyst samples are lower than those of impregnation catalyst samples,while surface Pd contents of sol-gel catalyst samples are higher than those of impregnation catalyst samples. For sol-gel catalyst samples,the formation rates of all products are higher than those of impregnation catalyst samples. Consequently,sol-gel catalyst performs a better catalytic activity compared with impregnation catalyst.