Effects of Cl− on Cu2O nanocubes for direct epoxidation of propylene by molecular oxygen.

Promoters have been widely used in industrial catalysis but understanding the mechanism behind their function is still a challenging subject. As ideal model catalysts, nanocrystal catalysts with well−defined exposing facets and relatively large specific surface have attracted intense attention. We explored the effect of Cl− loading on Cu 2 O nanocubes enclosed by (100) facets for the direct epoxidation of propylene by molecular oxygen. Interestingly, a volcano−type curve was obtained when the selectivity and conversion are plotted as a function of the loading amount of Cl−, indicating that optimal surface O/Cl− ratio is critical for desirable catalytic performance. Unlabelled Image • Using Cu 2 O nanocubes enclosed by (100) facets as model catalytic systems. • NH 4 Cl doping played a positive role for direct epoxidation of propylene. • The activity and selectivity critically depended on the loading amount of NH 4 Cl. [ABSTRACT FROM AUTHOR]