Catalytic Hydrotreatment of Algal HTL Bio‐Oil over Phosphide, Nitride, and Sulfide Catalysts

Global energy demand and environmental concerns about limiting CO2 emissions have been growing recently. This is why fuel production from renewable resources has become a priority. In this context, microalgae represent an attractive alternative carbon source. In this work, different supported catalysts, including metal phosphide, nitride, and sulfide, were tested for the hydroconversion of bio-oil issued from the hydrothermal liquefaction of microalgae. Supported Ni phosphide catalysts promoted the decarboxylation and decarbonylation route, while NiMo nitride promoted the hydrodeoxygenation pathway. NiW sulfide catalysts were the most performant, producing a hydrotreated oil with the best higher heating value (HHV), lower aromaticity degree, and lower average molar mass. Among sulfide catalysts, NiWS/SiO2-Al2O3 was the least active, probably due to the inhibition of acid sites by the nitrogen compounds. However, NiWS/Al2O3 performed better, showing high hydrogenation performances, which contributed to the conversion of refractory compounds.