Synthesis of Heterogeneous Metal Oxide Nanocatalysts and Their Applications in Biodiesel Production from Algal Oil: A Review

The need for sustainable and renewable energy sources is being given more attention to alternative sources of energy, such as those that do not rely on fossil fuels. Algal oil, derived from microalgae, is a required feedstock due to its high lipid content and extended growth rate. This review focuses on the synthesis of nano-heterogeneous catalysts and their application in biodiesel production from algal oil. Nano-catalysts provide enhanced surface area, superior activity, and recyclability, making them highly efficient for transesterification processes. The review explores different methods in synthesis of nano-catalysts by coprecipitation, hydrothermal, sol-gel, green method, impregnation method and combustion techniques. The Sol-gel method was found better for heterogeneous nano-catalyst synthesis. The role of different metal oxides like CaO, MgO, as well as metal oxide-supported nanostructures and functionalized materials in catalysis is critically analysed. The development of nano-heterogeneous catalysts in biodiesel production from algal oil offers a green and efficient route toward future energy solutions. This review uniquely highlights that sustainability and future energies align well with current global priorities. The previous reviews were lacking in such aspect.