摘要
Dry reforming of methane(DRM)has gained significant attention as a promising route to convert two major greenhouse gases(CO_(2) and CH4)to syngas.The development of efficient catalysts is critical for the engineering applications.In this study,the Ce_(x)Zr_(1-x)O_(2)/ZSM-5 composites with different oxygen vacancy concentrations were synthesized by tuning the Ce/Zr ratio,followed by the deposition of metal Ni to island-like Ce_(x)Zr_(1-x)O_(2)on ZSM-5,forming a variety of Ni-Ce_(x)Zr_(1-x)O_(2)/ZSM-5 catalysts,which were applied for the DRM reaction under 750◦C.Combined with various characterizations,it was found that the oxygen vacancy concentration illustrated the volcanic tendency with the decreased Ce/Zr ratio,and the interaction between metal Ni and Ce_(x)Zr_(1-x)O_(2)exhibited a positive relationship with oxygen vacancy concentration.The enhanced between Ni and Ce_(x)Zr_(1-x)O_(2)interaction could improve the strength and amount of Ni-O-M(M=Ce/Zr)species,making the d-band centers of catalysts closer to the Fermi energy level,which was beneficial to the CH4 and CO_(2) activation,along with the improved capacity to resist sintering and coking.Especially,the C1Z3(Ni-Ce0.25Zr0.75O_(2)/ZSM-5)catalyst with the Ce/Zr ratio of 1/3 demonstrated the optimal catalytic performance with 91.9%CH4 and 93.8%CO_(2) conversions within 50 h,accompanied by the best structural and catalytic stability after 100 h.In-situ DRIFTS was employed to study the reaction path and mechanism,discovering that significant amounts of strengthened Ni-O-M species were conducive to activating adsorbed CH4 and CO_(2),and desorbing the linear CO species.
基金
the following financial supports:National Natural Science Foundation of China(22075225 and 22038011)
Innovative Scientific Program of CNNC,State Key Laboratory of Clean and Efficient Coal Utilization,Taiyuan University of Technology(MJNYSKL202401,MJNYSKL202404).
