V2O5/TiO2催化剂活性组分与载体相互作用研究

制备了一系列负载型V-Ti-O催化剂, 运用现代分析测试手段如BET、TPD、NARP、XRD等进行表征. 研究发现负载于TiO_2上的V_2O_5由于相互作用而使其表面V=O物种选择外露, 载体TiO_2的晶体结构是决定它们之间相互作用的关键因素. 锐铁矿型TiO_2上获得最大V=O暴露的表面V_2O_5浓度显著低于金红石TiO_2载体上获得最大V=O暴露时的表面V_2O_5浓度. 而具有较大比表面及较强酸中心的TiO_2载体导致较强的相互作用. 即可获得较大的表面V=O暴露度.

STUDY ON THE INTERACTION BETWEEN THE ACTIVE PHASE AND SUPPORT ON V_2O_5/TiO_2 CATALYST

V_2O_5 supported on various TiO_2 including anatase,rutile and mixture of bothtypes have been investigated with various physicochemical measurements such as BET,TPD,NARP,XRD and so on.It has been found that the V=O species or the(010)plane of V_2O_5 on all the TiO_2 supports with large BET surface area are selectivelyexposed to the surface,though different modifications of TiO_2 results in differentcharacteristics of exposure of(010)plane.For anatase,the maximum exposure ofthe V=O species is obtained at the surface concentration of V_2O_5 significantly lowerthan that for rutile.For the mixture,two maxima are obtained in the surface con-centration of V_2O_5 corresponding to those for anatase and rutile respectively.Thus,itis concluded that crystal structure of the TiO_2 support determines the maximum ex-posure of(010)plane.The chemical activity of TiO_2 surface also seems to have aneffect on the exposure of(010)plane.That is,the higher surface area and thestronger acidic property resulted in the high exposure of(010)plane.