CAJ | 학술논문

采用分步共沉淀法制备了不同Al2O3含量(0%-15%(w))的CuO/Fe2O3催化剂,并进行水煤气变换反应(WGSR)评价测试。制得的催化剂中含有复合物CuFe2O4,其晶粒尺寸,氧化还原性质和表面Cu分散通过相应表征手段加以研究。 X射线粉末衍射(XRD),拉曼(Raman)光谱, N2物理吸附, N2O分解和CO2程序升温脱附(CO2-TPD)等表征技术说明适量Al2O3的加入可以促进尖晶石CuFe2O4发生由四方相向立方相的转变,阻止催化剂中Cu烧结,增大表面Cu分散,增加弱碱性位点的数量。此外,采用H2程序升温还原(H2-TPR)技术探究改性的CuO/Fe2O3催化剂的还原性能。关联结果发现, Al2O3掺杂在增大铜物种的耗氢量,降低其还原温度方面起着重要的作用。即Al2O3的添加促进CuO/Fe2O3催化剂中铜铁物种之间的协同作用。结合活性测试和表征结果,适量的Al2O3(10%(w))改性的催化剂具有较小的Cu颗粒尺寸、较大的Cu分散、较强的还原性能、较多数量的弱碱性位点,因此具有更好的初始活性和热稳定性。
채용분보공침정법제비료불동Al2O3함량(0%-15%(w))적CuO/Fe2O3최화제,병진행수매기변환반응(WGSR)평개측시。제득적최화제중함유복합물CuFe2O4,기정립척촌,양화환원성질화표면Cu분산통과상응표정수단가이연구。 X사선분말연사(XRD),랍만(Raman)광보, N2물리흡부, N2O분해화CO2정서승온탈부(CO2-TPD)등표정기술설명괄량Al2O3적가입가이촉진첨정석CuFe2O4발생유사방상향립방상적전변,조지최화제중Cu소결,증대표면Cu분산,증가약감성위점적수량。차외,채용H2정서승온환원(H2-TPR)기술탐구개성적CuO/Fe2O3최화제적환원성능。관련결과발현, Al2O3참잡재증대동물충적모경량,강저기환원온도방면기착중요적작용。즉Al2O3적첨가촉진CuO/Fe2O3최화제중동철물충지간적협동작용。결합활성측시화표정결과,괄량적Al2O3(10%(w))개성적최화제구유교소적Cu과립척촌、교대적Cu분산、교강적환원성능、교다수량적약감성위점,인차구유경호적초시활성화열은정성。
The water-gas shift reaction (WGSR) has been carried out over CuO/Fe2O3 catalysts modified by different loadings of Al2O3 (0%-15%(w)), prepared by a stepwise co-precipitation method. Composite mixture CuFe2O4 was produced, and the crystal ine size, redox property, and surface metal ic Cu dispersion were manipulated. The appropriate introduction of Al2O3 can promote the phase transition of spinel CuFe2O4 from tetragonal to cubic, inhibit aggregation of Cu-crystal ite, improve Cu dispersion, and increase the amount of weak basic sites, as confirmed using powder X-ray diffraction (XRD), Raman spectroscopy, N2 physisorption, N2O decomposition, and temperature-programmed desorption of carbon dioxide (CO2-TPD) techniques. In addition, a temperature-programmed reduction of hydrogen (H2-TPR) technique was used to investigate the reducibility of the modified CuO/Fe2O3 catalysts. It was found that the Al2O3-doping plays an important role in increasing the hydrogen consumption of the copper species, and decreasing reduction temperature. This means that the Al2O3 can promote a synergistic interaction between the copper and iron species in the CuO/Fe2O3 catalysts. Overal , the Al2O3-modified catalyst (10%(w)) has a smal er Cu particle size, better Cu dispersion, greater reducibility, and larger amount of weak basic sites, resulting in a much higher initial catalytic activity and better thermal stability.