Ultralow-Loading Pt Clusters Synergizing with P–OH Sites for Efficient Hydrodeoxygenation of Fatty Acids/Methyl Esters

Highly dispersed Pt nanoclusters uniformly anchored on a mesoporous NbOPO4 were designed for efficient hydrodeoxygenation of fatty acids/methyl esters. This high activity stems from a P-induced electronic synergy: electron-deficient Nb5+ sites polarize carboxyl groups, while Ptδ+ clusters dissociate H2, with spillover hydrogen transported via P–OH bridges. This concerted mechanism drives direct dehydration-hydrogenation of a gem-diol/alkenol intermediate, bypassing aldehyde formation and suppressing decarboxylation. The catalyst demonstrates generality, affording near-theoretical yields of Cn alkanes from C12–C18 feedstocks (acids, esters, triglycerides) with a productivity of 415 gCn-alkane·gPt–1·h–1, rendering it highly competitive among those reported for sulfur-free hydroprocessed esters and fatty acid (HEFA) catalysts. The 0.1 wt % Pt/NbOPO4(0.3P) catalyst achieves quantitative, >99% yield conversion of palmitic acid to C16 alkanes under 3 MPa initial H2 pressure with required reaction times spanning from 4 to 12 h depending on feedstock complexity, significantly outperforming an impregnated 1 wt % Pt analog. DFT calculations confirm Nb5+ adsorption and polarization of the −COOH group and further demonstrate that the energy landscape is lower for Brønsted acid-mediated hydrogen spillover, which facilitates H migration to −COOH. This work elucidates the Brønsted acid and spillover effects that maximize noble-metal efficiency and establishes a scalable route for carbon-conservative HEFA.