摘要
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.
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.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
1993年第4期501-508,共8页
Acta Physico-Chimica Sinica
关键词
催化剂
五氧化二钒
二氧化钛
V_2O_5
TiO_2
Interaction
Crystal structure
