Layered double hydroxides-based nanomaterials for biodiesel production

Biodiesel synthesis via catalytic transesterification has emerged as a promising sustainable energy production process. Developing green and efficient catalysts is crucial to enable industrially biodiesel production. Recently, advanced layered double hydroxides (LDHs)-based nanomaterials have received extensive attention owing to their thermal stability, composition and alkalinity adjustability, enabled by the presence of various metal cations and interlayer anions. However, the targeted design of LDHs-based nanomaterials, including tuning the structural composition of LDHs to systematically understand the structure-activity relationships between LDHs structures and their catalytic transesterification activity, remains challenging. Additionally, the integration of LDHs-based catalysts with advanced reaction systems to improve biodiesel yield has yet to be explored. This review systematically explores the prospects of LDHs-based catalysts in biodiesel production and gives emphasis on the reaction mechanism, catalyst design principles, and reaction systems optimization. This review begins with an overview of the catalytic transesterification mechanism, detailing the preparation methods for LDHs and their derivatives, especially the advanced design strategies. The applications of LDHs-based catalysts in biodiesel production are summarized, highlighting the structure-activity relationship that govern biodiesel yield. Furthermore, we focus on the recent developments of advanced reaction systems used to improve conversion efficiency. Finally, the challenges and prospects concerning the application of LDHs-based nanomaterials for biodiesel production are also discussed. This review will provide critical guidance for designing high-efficiency LDHs-based catalysts and integrating them with advanced reaction systems, thereby advancing innovations in biodiesel production.