Facile synthesis of H3PW12O40 supported on phenolic resin-functionalized Ti-mesoporous silica composite: Dual-acid sites and high hydrophobicity for efficient biodiesel production from methyl oleate

With the accelerated consumption of fossil fuels driven by societal development and population growth, acid-catalyzed biodiesel serves as an eco-friendly alternative that effectively enhances reaction processes and reduces pollutant emissions. This study developed a novel dual-acid catalyst, H 3 PW 12 O 40 (PW) and titanium-incorporated phenolic resin (PR) functionalized mesoporous silica (PW/Ti-SiO 2 -PR), via a one-pot hydrothermal method for efficient biodiesel production via oleic acid esterification. The composite’s structure, acidity, and hydrophobicity were systematically characterized using FT-IR, XRD, N 2 physisorption, SEM/TEM, and XPS. Results confirmed the successful integration of PW and Ti into the silica framework, creating synergistic Brønsted (PW) and Lewis (Ti 4 + ) acid sites. The inclusion of low-molecular-weight PR enhanced mesopore formation and hydrophobicity, critical for inhibiting water-induced deactivation. The optimized 0.2PW/Ti0.05-SiO 2 -PR0.25 catalyst achieved 95.2 % methyl oleate yield at 100 °C within 8 h, outperforming conventional solid acids. Notably, the catalyst retained > 90 % activity over five cycles without PW leaching or structural degradation, demonstrating exceptional stability. This work highlights the strategic design of hydrophobic, dual-acid mesoporous catalysts for sustainable biodiesel synthesis.