Reaction induced Ni/MgTi2O5 interface promotes the resistance to sintering and oxidation in auto-thermal reforming of acetic acid

Abstract

Hydrogen can be produced from acetic acid (HAc) derived from renewable biomass oil via auto-thermal reforming (ATR), which is conducive to upgrading current energy supply in a carbon-neutral and clean way. However, deactivations caused by carbon deposition, sintering, and oxidation have been long-standing obstacles for nickel-based catalysts. To address these challenges, we synthesized a series of Ni-Mg-Ti-O catalysts by Pechini method and tested in ATR. Characterization results showed that mixed oxide of Ni1-xMgxTiO3±δ perovskite was formed after calcination and transformed into Ni0, MgTiO3 and TiO2 after hydrogen reduction, while the Ti4+/Ti3+ redox cycle promoted formation of oxygen vacancies. In addition, the in-situ evolution of MgTiO3 and TiO2 into MgTi2O5 during the ATR reaction was proved, which suppressed sintering and oxidation of Ni species. Density functional theory (DFT) study confirmed the electron transfer over the Ni/MgTi2O5 interface, as well as the enhanced metal-support interaction, which promoted adsorption and dissociation of acetic acid molecules. Consequently, the Ni0.08Mg0.10Ti0.37O0.92±δ (N10MT) catalyst with Ni/MgTi2O5 interface showed high stability and activity with hydrogen yield at 2.72 mol-H2/mol-HAc.