Towards sustainable catalysts in hydrodeoxygenation of algae-derived oils: A critical review

Sequel to the future challenges identified in the energy indicators, the exploration of algae-biomass resources increasingly becoming an issue of interest. Algae-derived oils are accordingly considered as alternative fuels with great future prospects. However, their direct utilization is scientifically difficult due to associated complex compositions. So far, hydrodeoxygenation (HDO) of the oils is increasingly viewed as the reliable upgrading process for deriving high quality fuels. The paper therefore explored and critically examined substantial literature on the updates related to catalyst design and testing for HDO, the influence of oil production techniques on its susceptibility to HDO, effects of parameters such as catalyst sulfidation, modification to phosphides, nature of support systems and preparation versus reaction conditions. In addition to highlights on reaction mechanisms, the paper also discussed the effect of hydrothermal treatment on HDO catalyst stability and provided insights into areas for further investigations.