摘要
The thermal stability of Ce_(2) nanomaterials can directly impact both the uniformity of the supported catalysts and the catalytic behavior of Ce_(2) itself.However,knowledge about the thermal stability of Ce_(2) is still deficient.Here,we conduct in-situ transmission electron microscopy experiments and theoretical calculations to elucidate the thermal stability of Ce_(2) nanomaterials under different environments.A sinter(<700℃)and a structural decomposition(>700℃)are observed within Ce_(2) nanoflowers under O_(2).The sinter firstly occurs among the nanoflowers’monomers and then the sintered nanoparticles structurally decompose to tiny nanoparticles from the strain interface.Under a vacuum environment,the Ce_(2) nanoflowers firstly undergo a transition from cubic fluorite Ce_(2) to hexagonal Ce_(2)O_(3),accompanied by the oxygen release.The Ce_(2)O_(3) nanoparticles further atomically sublimate from the edges to the center under high temperatures.Theoretical calculation results reveal a considerably lower energy barrier for the structural decomposition under O_(2) and for the sublimation under vacuum.This work provides a perspective on the structural design and performance optimization of Ce_(2)-based catalysts.
基金
supported by the National Key R&D Program of China(No.2017YFA0204800)
the National Natural Science Foundation of China(Nos.11674052,11525415,and 21975042)
the Project of Six Talents Climax Foundation of Jiangsu(Nos.XNL-044 and XCL-082).
