In this work,a series of Ce-Ti composite oxides with different Ti/Ce molar ratios was prepared by coprecipitation method,and investigated for the catalytic degradation of toluene and selective catalytic reduction of N...In this work,a series of Ce-Ti composite oxides with different Ti/Ce molar ratios was prepared by coprecipitation method,and investigated for the catalytic degradation of toluene and selective catalytic reduction of NO.The phase transition process between Ce species and Ti species is limited by modulating the interaction between Ce4+and Ti4+,while a completely amorphous composite is generated with an appropriate molar ratio of Ti/Ce(1.5/1).The catalyst CeTi1.5Oxexhibits the best catalytic performance,where the values of T90and T50for deep degradation of toluene are 297 and 330℃respectively at high weight hours space velocity(WHSV=120000 mL/(g·h)).Compared with CeO_(2),T90and T50decrease by48 and 34℃respectively while declining by 67 and 70℃compared to TiO_(2).For the SCR reaction,CeTi1.5Oxreaches 100%NO conversion at 250℃with WHSV=60000 mL/(g·h),reduced by 50℃compared to pure CeO_(2).The amorphous nanostructure with highly dispersed Ce and Ti species was confirmed by transmission electron microscopy(TEM)and X-ray diffraction(XRD)characterizations.The X-ray photoelectron spectroscopy(XPS)and Raman analyses show that a large number of active Ce-O-Ti species and surface oxygen vacancies are generated due to the strong interaction between Ti^(4+)and Ce^(4+)in CeTi_(1.5)O_(x).Additionally,H_(2)-TPR and O_(2)-TPD further confirm that the interaction promotes the low-temperature reducibility and mobility of surface-active oxygen species.Meanwhile,in-situ DRIFTS study reveals that CeTi1.5Oxwith amorphous nanostructure can dramatically enhance the dissociative and complete oxidation capacity for toluene.展开更多
基金Project supported by the National Natural Science Foundation of China(22072096,22108184)。
文摘In this work,a series of Ce-Ti composite oxides with different Ti/Ce molar ratios was prepared by coprecipitation method,and investigated for the catalytic degradation of toluene and selective catalytic reduction of NO.The phase transition process between Ce species and Ti species is limited by modulating the interaction between Ce4+and Ti4+,while a completely amorphous composite is generated with an appropriate molar ratio of Ti/Ce(1.5/1).The catalyst CeTi1.5Oxexhibits the best catalytic performance,where the values of T90and T50for deep degradation of toluene are 297 and 330℃respectively at high weight hours space velocity(WHSV=120000 mL/(g·h)).Compared with CeO_(2),T90and T50decrease by48 and 34℃respectively while declining by 67 and 70℃compared to TiO_(2).For the SCR reaction,CeTi1.5Oxreaches 100%NO conversion at 250℃with WHSV=60000 mL/(g·h),reduced by 50℃compared to pure CeO_(2).The amorphous nanostructure with highly dispersed Ce and Ti species was confirmed by transmission electron microscopy(TEM)and X-ray diffraction(XRD)characterizations.The X-ray photoelectron spectroscopy(XPS)and Raman analyses show that a large number of active Ce-O-Ti species and surface oxygen vacancies are generated due to the strong interaction between Ti^(4+)and Ce^(4+)in CeTi_(1.5)O_(x).Additionally,H_(2)-TPR and O_(2)-TPD further confirm that the interaction promotes the low-temperature reducibility and mobility of surface-active oxygen species.Meanwhile,in-situ DRIFTS study reveals that CeTi1.5Oxwith amorphous nanostructure can dramatically enhance the dissociative and complete oxidation capacity for toluene.
