物理化学学报
物理化學學報
물이화학학보
ACTA PHYSICO-CHIMICA SINICA
2013年
4期
799-805
,共7页
陈傲昂%许响生%华焱祥%顾辉子%严新焕*
陳傲昂%許響生%華焱祥%顧輝子%嚴新煥*
진오앙%허향생%화염상%고휘자%엄신환*
钌%四氧化三铁%催化剂稳定性%3,4-二氯硝基苯%原位液相加氢%CO中毒失活
釕%四氧化三鐵%催化劑穩定性%3,4-二氯硝基苯%原位液相加氫%CO中毒失活
조%사양화삼철%최화제은정성%3,4-이록초기분%원위액상가경%CO중독실활
Ruthenium%Iron oxide%Catalytic stability%3,4-Dichloronitrobenzene%In-situ liquid phase hydrogenation%CO poisoning deactivation
采用分步浸渍法制备负载型Ru-Fe3O4/γ-Al2O3催化剂,并利用透射电子显微镜(TEM)、X射线衍射(XRD)、N2吸附-脱附(BET)、傅里叶变换红外(FTIR)光谱与X射线光电子能谱(XPS)表征催化剂的纳米颗粒粒径分布、晶相组成、表面结构及吸附物种等性质.将Ru-Fe3O4/γ-Al2O3催化剂用于3,4-二氯硝基苯选择性原位液相加氢反应,考察了反应条件对催化活性的影响,并讨论了不同制备条件下催化剂的稳定性能.结果表明,在473 K、液压3 MPa、原料质量分数2%,乙醇/水体积比75:25的反应条件下,3,4-二氯硝基苯的转化率为100%,3,4-二氯苯胺的选择性高达96.4%. Fe3O4含量对催化剂稳定性能有显著影响,当Ru和Fe的质量分数分别为2%和6%时,催化剂可稳定200 h以上.表面吸附CO与积碳是导致催化剂失活的主要原因,以Fe3O4作为高效的助剂,进行水汽转换(WGS)反应与费托合成(FTS)可移除CO,而采用煅烧法去除表面积碳.晶相变化与纳米颗粒的聚集可能导致催化剂部分失活,其原因以及再生方法需进一步考察.
採用分步浸漬法製備負載型Ru-Fe3O4/γ-Al2O3催化劑,併利用透射電子顯微鏡(TEM)、X射線衍射(XRD)、N2吸附-脫附(BET)、傅裏葉變換紅外(FTIR)光譜與X射線光電子能譜(XPS)錶徵催化劑的納米顆粒粒徑分佈、晶相組成、錶麵結構及吸附物種等性質.將Ru-Fe3O4/γ-Al2O3催化劑用于3,4-二氯硝基苯選擇性原位液相加氫反應,攷察瞭反應條件對催化活性的影響,併討論瞭不同製備條件下催化劑的穩定性能.結果錶明,在473 K、液壓3 MPa、原料質量分數2%,乙醇/水體積比75:25的反應條件下,3,4-二氯硝基苯的轉化率為100%,3,4-二氯苯胺的選擇性高達96.4%. Fe3O4含量對催化劑穩定性能有顯著影響,噹Ru和Fe的質量分數分彆為2%和6%時,催化劑可穩定200 h以上.錶麵吸附CO與積碳是導緻催化劑失活的主要原因,以Fe3O4作為高效的助劑,進行水汽轉換(WGS)反應與費託閤成(FTS)可移除CO,而採用煅燒法去除錶麵積碳.晶相變化與納米顆粒的聚集可能導緻催化劑部分失活,其原因以及再生方法需進一步攷察.
채용분보침지법제비부재형Ru-Fe3O4/γ-Al2O3최화제,병이용투사전자현미경(TEM)、X사선연사(XRD)、N2흡부-탈부(BET)、부리협변환홍외(FTIR)광보여X사선광전자능보(XPS)표정최화제적납미과립립경분포、정상조성、표면결구급흡부물충등성질.장Ru-Fe3O4/γ-Al2O3최화제용우3,4-이록초기분선택성원위액상가경반응,고찰료반응조건대최화활성적영향,병토론료불동제비조건하최화제적은정성능.결과표명,재473 K、액압3 MPa、원료질량분수2%,을순/수체적비75:25적반응조건하,3,4-이록초기분적전화솔위100%,3,4-이록분알적선택성고체96.4%. Fe3O4함량대최화제은정성능유현저영향,당Ru화Fe적질량분수분별위2%화6%시,최화제가은정200 h이상.표면흡부CO여적탄시도치최화제실활적주요원인,이Fe3O4작위고효적조제,진행수기전환(WGS)반응여비탁합성(FTS)가이제CO,이채용단소법거제표면적탄.정상변화여납미과립적취집가능도치최화제부분실활,기원인이급재생방법수진일보고찰.
@@@@Ru-Fe3O4/γ-Al2O3 was synthesized by stepwise impregnation method and applied to the in-situ liquid phase selective hydrogenation of 3,4-dichloronitrobenzene (3,4-DCNB). The nanoparticle size and distribution, metal ic crystal ine constitution, surface structure parameters, and adsorption species were systematical y characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, N2 adsorption-desorption (BET), and X-ray photoelectron spectroscopy (XPS). The Ru-Fe3O4/γ-Al2O3 catalyst was investigated using the in-situ liquid phase hydrogenation of 3,4-DCNB as probe reaction, the effect of different reaction conditions and different synthetic factors on the catalytic properties was studied. Experimental results showed that the catalytic properties of the Ru-Fe3O4/γ-Al2O3 catalyst were significantly influenced by its Fe3O4 content, under the optimum condition of 473 K, 3.0 MPa, 2%(w) 3,4-DCNB concentration with 75%ethanol and 25%water, the Ru-Fe3O4/γ-Al2O3 catalyst with Ru and Fe mass fractions of 2% and 6% exhibited the highest activity and stability, with 100%conversion of 3,4-DCNB, 96.4%selectivity of 3,4-dichloroaniline (3,4-DCAN), and this catalyst could be stabilized for more than 200 h. The main reason for the deactivation of the catalyst is CO coverage on active centers, and the poisoning-deactivated catalysts were regenerated by water-gas-shift (WGS) reaction and Fischer-Tropsch synthesis (FTS), which employ Fe3O4 modified Ru/Al2O3 as catalyst due to its high efficiency of CO transformation. Carbon deposition on the catalyst surface is the reason second only to carbon monoxide poisoning, and this could be removed through calcination. Crystal ine phase change and nanoparticles aggregation may cause partial deactivation, and investigation of the mechanism and catalyst regeneration are in progress.
