MOF-based catalysts for sustainable biodiesel production: classification, performance, and advances from 2020 to 2025.

Global energy demand and environmental concerns have intensified the search for renewable fuels, with biodiesel emerging as a sustainable substitute for petroleum diesel. Efficient catalysis remains the bottleneck for large-scale biodiesel production. While heterogeneous catalysts offer advantages of reusability and separation, their performance is limited by stability, active sites availability, and reduced activity under harsh conditions. Metal-organic frameworks (MOFs), with their high surface area, tunable porosity, and structural versatility, have recently attracted increasing attention as next-generation catalysts. This work reviewed advances in the design and application of each common MOF type for biodiesel synthesis through esterification and transesterification process. MOF composites, MOF derivatives, and MOF composite materials exhibit superior catalytic performance and recyclability compared to pristine MOFs, making them highly recommended for future research and applications. Beyond summarizing yields and reaction conditions, we highlight mechanistic insights, stability issues, and catalysis performance. Special attention is given to functionalized and composite MOFs, bifunctional systems, and enzyme-MOF hybrids, which demonstrate superior performance compared to pristine MOFs. While UiO- and ZIF-based MOFs dominate current research, emerging systems such as Ca- and Cu-MOFs remain underexplored yet promising. We analyze the key features required in MOF materials for efficient biodiesel production and provide a comprehensive review and categorization of recent advancements. By contrasting MOFs with conventional heterogeneous catalysts and positioning this review against existing literature, we provide a comprehensive and critical perspective on the opportunities and challenges of MOFs in biodiesel catalysis.