Han, Xinru; Wen, Haojue; Hao, Yingdong; Chen, Kaifei; Zhang, Lina; Chen, Yongdong; Wei, Wei; Sun, Nannan

JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING

2025, 2,

Han, Xinru; Wen, Haojue; Hao, Yingdong; Chen, Kaifei; Zhang, Lina; Chen, Yongdong; Wei, Wei; Sun, Nannan

ZnZ5(Na)-y catalysts were prepared by loading Zn onto NaZSM-5 with different Si/Al ratios for oxidative dehydrogenation of C2H6 using CO2 as a soft oxidant. The obtained samples were comprehensively characterized, with particular emphasis on the interplay between the Si/Al ratios dictated surface acidity, the speciation of Zn species, and the catalytic performance. It was found that in samples with lower Si/Al ratios, ZnOH+ species (rather than ZnO cluster) is preferentially generated. This species is thermodynamically more favorable for C2H6 activation, and its high dispersion further enhances the reaction from a kinetic perspective. The optimum catalyst, ZnZ5(Na)-10, showed excellent performance over most of the reported systems, only insignificant formation of carbon was observed, which induced rapid deactivation during the initial stage of the reaction. After this, the deactivation slows down, and Zn leaching is attributable for the long-term deactivation. This study shed new lights on the design of effective active sites for CO2-ODH, which is a promising process for both the production of platform chemicals and CO2 mitigation.