Heteropoly Acid/La-Based Solid Acid Catalysts for Extraction–Oxidative Desulfurization of Liquid Fuel Models

Abstract In this study, lanthanum phosphomolybdate (LaPMo12O40, denoted as LaPMo) was synthesized via an evaporation–crystallization strategy using phosphomolybdic acid and lanthanum nitrate as precursors. The obtained material was then used as a solid acid catalyst for the extraction–oxidative desulfurization (ECODS) of model fuels. The structural and physicochemical properties of LaPMo were systematically characterized by FT-IR, XRD, XPS, SEM, EDS, and BET analyses, which confirmed the successful formation of the catalyst and provided insights into its morphology and stability. Under the optimized conditions, a desulfurization efficiency of 96.30% was achieved at 60°C within 0.5 h using 30 wt % H2O2 as the oxidant. Moreover, the catalyst exhibited good recyclability, maintaining a desulfurization efficiency above 90% after six consecutive cycles. Thus, LaPMo demonstrated a strong catalytic activity toward thiophene oxidation and showed promise as an efficient and reusable catalyst for practical desulfurization applications.