free (daf) basis, corresponding to a decrease in the carbon recovery from 39 to 37%. Using zeolite H-ZSM-5 mixed with alumina as support with a CoMo loading of 4.1 wt%, the condensed organics contained only 5.2 to 6.1 wt% db oxygen. The condensable organic yield was between 23.9 and 24.4 wt% db, and the carbon recovery was 39–40%. Thus using an acidic support can remove the oxygen without decreasing the carbon recovery. The latter was ascribed to alkylation of the aromatics when the zeolite support was used.
Elemental maps of the spent catalysts were obtained using STEM-EDS, showing that the CoMo phase was mainly located as monolayer MoS2 slab structures (> 93%) on the support and indicated a high dispersion of cobalt, consistent with incorporation of Co into the MoS2 structure in the CoMoS phase. Potassium was observed on all the spent catalysts, indicating transfer of alkali metal from the biomass to the catalyst. Potassium may decrease the acidity of the catalyst over time, thus reducing the positive effect of using a more acidic support.
- Molybdenum sulfide