Hydrodeoxygenation of anisole to benzene over an Fe2P catalyst by a direct deoxygenation pathway

Abstract

Developing economically viable and highly selective hydrodeoxygenation (HDO) catalysts for the C–O bond cleavage of lignin-derived aryl ethers is very important, but still challenging. Herein, a novel monometallic Fe₂P catalyst was synthesized by a two-stage phosphorization method under mild conditions, which showed a high arene (benzene) selectivity of 96.7% among C₆⁺ products with a turnover frequency of 8.2 × 10⁻³ mol mol_CO⁻¹ s⁻¹ in the HDO of anisole at 200 °C and ambient hydrogen pressure. Characterization results revealed that the crystal structure of the Fe₂P catalyst was stable and no phosphorus loss occurred in the reduction and reaction process. The kinetic results indicated that the coverage of anisole was higher than that of H₂ on the Fe₂P catalyst. The anisole temperature-programmed surface reaction (anisole-TPSR) and density functional theory (DFT) calculation results identified that the anisole HDO reaction mechanism is the direct cleavage of the C_aryl–O bond of anisole to form and CH₃O* without forming the C₆H₅–OH–CH₃ intermediate. These findings may contribute toward understanding the iron-based phosphide and guiding the catalyst design for the HDO of aryl ethers and related reactions.