Cox-Co2Mo10/Cox/SiO2 catalysts with various Co content in precursor or support are prepared. Thiophene and hexene-1 conversions increase with Co loading. HDS/HYDO selectivity increases with CoMoS promotion. HDS/HYDO selectivity decreases due to CoSx/SiO2 and H2 spillover. TPR confirms that CoSx/SiO2 facilitates the reduction of MoS2/SiO2 in separate bed. Catalyst with fully promoted edges' active sites has highest selectivity factor.