Dysprosium promotion on Co/Al2O3 catalysts towards enhanced hydrogen generation from methane dry reforming

Dysprosium (Dy) promoted Co/Al2O3 catalysts with different Dy loadings (0-3 wt%) were synthesized via an impregnation approach for methane dry reforming. Promoter addition enhanced the basicity of catalysts owing to the basic attribute of Dy2O3. Co3O4 crystallite sizes were reduced from 8.15 to 6.68 nm with 0.1-0.3 wt%Dy promotion due to the diluting effect, resulting in higher metal dispersion. Particularly, at 973 K, 0.3 wt%Dy appeared as the best promoter loading and achieved the highest CH4 conversion, as well as H-2 and CO yields of the corresponding 79.4%, 65.8% and 89.2% because of growing basic site density and the enhancing number of Co active sites. The temperature-programmed oxidation analyses also revealed that 0.3%Dy-10%Co/Al2O3 suppressed carbonaceous deposition from 12.84% to 7.76% since the extra oxygen mobility and redox cycling of Dy2O3 could effectively oxidize surface carbonaceous species to CO and H-2.