An Insight into the Performance and Prospect of Catalysts in Biodiesel Production, with Special Emphasis on Heterogeneous Based Catalysis

Fossil fuel depletion, increased world energy demand, and the environmental crisis linked to petroleum-based energy instigated the quest for its substitute. The sustainability of biodiesel affords it a high prospect over fossil fuels. It has been receiving attention as a result of its biodegradability, renewability, low toxicity, and good transport and storage properties. The main shortcomings of biodiesel are the production cost and choice of catalyst. Three types of catalysts mainly used for biodiesel production are basic, acidic, or enzyme. Industrial production of biodiesel typically employed homogeneous catalysts due to their ability to facilitate the reaction quickly. However, catalyst separation and biodiesel purification are tormenting, requiring a large amount of water. Thus, heterogeneous catalysts, with several advantages over homogenous catalysts, have been searched. Heterogeneous catalysts can be separated from the products effortlessly, thus allowing for recycling. Furthermore, the process is simpler, cheaper, and more environmentally benign. This review aims to evaluate the performance of different types of catalysts in the transesterification reaction, with special emphasis on heterogeneous base catalysts. The review also gives insight into the key catalytic properties that need to be tailored economically and eco-friendly to reduce cost, to give better biodiesel yield/conversion. Additionally, the various conditions necessary for the optimum yield of biodiesel have also been explored. Lastly, the future challenges and prospects of heterogeneous base catalysts are proposed. Keywords: Biodiesel, Catalyst performance, Heterogeneous catalyst, Transesterification