Highly efficient aqueous-phase hydrogenation of biomass-derived levulinic acid to γ-valerolactone over Ni3P/MCM-41 catalyst: The critical role of phosphorus modification and reaction pathways

The aqueous-phase hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL) is crucial for biomass valorization. To address the need for efficient and stable catalysts, we developed P-modified Ni/MCM-41 catalysts.  Importantly, precise control of the Ni:P ratio governs the formation of specific Ni-P phases, which directly determines catalytic activity. The optimal Ni₃P phase (Ni:P = 3:1) achieved 100 % GVL yield under mild conditions (80 °C, 10 h), significantly outperforming the inactive Ni₂P formed with excess P. Comprehensive characterization revealed that P enhances Ni dispersion and induces an electron-deficient state (Ni^δ+) via Ni → P charge transfer. In situ FTIR and adsorption studies demonstrated preferential LA adsorption on Ni₃P and identified angelica lactones as key intermediates,  thereby elucidating the reaction pathway that promotes selective hydrogenation over side reactions. The Ni₃P/MCM-41 catalyst-maintained its activity over four cycles. This work establishes fundamental structure–activity relationships and highlights precise Ni–P phase control as a critical design strategy for sustainable catalysis.