Recent advances in biodiesel production using functional carbon materials as acid/base catalysts

Biodiesel is regarded as an excellent substitute or additive to fossil diesel. Carbon materials are favorable platform to synthesize acid and/or base catalysts for transformation of renewable oil into biodiesel owing to their remarkable merits, including structural diversity, controlled surface properties, excellent stability, and no toxicity. Due to the fast-growing development of this subject matter, it is high time to summarize the recent progress. Consequently, this review systematically summarized the most up-to-date advances on the application of functionalized carbon-based catalysts for upgrading renewable oil into biodiesel, including (1) summary of the common feedstocks for producing biodiesel; (2) synthesis methods of carbonaceous materials; (3) synthesis methods and catalytic activities of various carbon-based solid acid and base catalysts; and (4) the reusability and deactivation of the catalyst. Meanwhile, effect of physicochemical properties, including acidity/basicity, hydrophilicity/hydrophobicity, and porosity of catalysts on their catalytic activity was analyzed. Finally, a brief conclusion of this review, and challenges and future perspectives towards this subject matter were also proposed. Combination of multiple outstanding properties in a carbon-based catalyst is feasible to obtain excellent catalytic performance in production of biodiesel. We believe this review will be meaningful for developing state-of-the-art carbon-based catalyst for biodiesel production.