Metal-organic framework as a heterogeneous catalyst for biodiesel production: A review

Nowadays, as there is a rapid depletion of fossil fuels, the need for alternative resources has become inevitable. Biodiesel is such an alternative that is environmentally friendly and sustainable. Over the years there has been a significant amount of research done for biofuel production by converting various feedstocks such as edible and non-edible vegetable oil, animal fats, waste cooking oil, and microalgae as the feedstock which requires a highly workable and efficient catalyst for the transesterification process. Several heterogeneous catalysts have been used for the transesterification of biodiesel feedstock to biodiesel, among which metal-organic framework (MOF) has gained popularity owing to its high surface area, high pore volume, and facile tunability of the active sites. This review focuses on different types of MOFs, characterization techniques used to identify vital structurally invoked changes, and deactivation of MOFs due to leaching of various active species, blocking of active sites, and unzipping of MOFs by covering the literature from the year 2000 to till date. Finally, a brief conclusion and the author's perspective depicting several challenges and scope for future research needs in the MOF study have been provided.