Hybrid Organometallic Nanostructured Catalysts for One-Pot Esterification–Transesterification of High-FFA Feedstocks

Biodiesel production from high free fatty acid (FFA) algal oils presents both a sustainable energy solution and a catalytic challenge due to the need for simultaneous esterification and transesterification. Conventional catalysts often lack the bifunctionality required to process such complex feedstocks effectively. This study addresses this limitation by engineering a novel hybrid nanocatalyst, Co-salen@MoS₂, which combines the Lewis acidity of cobalt–salen complexes with the high surface area and stability of MoS₂ nanosheets. The synthesis involved hydrothermal fabrication of MoS₂ followed by reflux-based Co-salen complexation and mechanochemical anchoring. Comprehensive characterizations, including XRD, FTIR, BET, TEM, and TGA, validated the hybrid’s structural integrity and porosity. Catalytic performance was assessed through biodiesel production from Nannochloropsis sp. oil, yielding more than 93% at a 1 wt% catalyst dosage. The catalyst demonstrated 97% activity retention after five cycles and outperformed carbonyl@WS₂ and bipyridyl@MoSe₂ in both yield and thermal stability, reducing activation energy by up to 50%. These results underscore the synergistic effect of organometallic coordination and 2D nanostructuring in enhancing reaction kinetics and durability. The study confirms Co-salen@MoS₂ as a promising candidate for industrial biodiesel applications and lays the groundwork for future exploration of multifunctional nanocatalyst systems in green energy production.