Achieving High-Quality Biofuel from Catalytic Upgrading of Sewage Sludge Hydrothermal Liquified Biocrude on Ceria-Supported Cobalt Catalysts

Co/CeO₂ catalysts with different morphologies of polyhedrons (Co/CeO₂-P), rods (Co/CeO₂-R), sheets (Co/CeO₂-S) and cubes (Co/CeO₂-C) were prepared and compared on the catalytic upgrading of hydrothermal liquefied (HTL) biocrude derived from municipal sewage sludge (MSS) to biofuel. The best quality biofuel was achieved on Co/CeO₂-C with a higher heating value (HHV) of 39.10 MJ/kg, where the sulfur and oxygen contents were reduced to 0.007 and 9.19 wt %, while the carbon and hydrogen contents were elevated to 77.5 and 10.1 wt %, respectively. In contrast, the pure ceria support presented a slight improvement for the upgrading of biocrude. Overall, this work provides a feasible solution for high-value utilization of MSS to produce high-grade biofuel.