Design of Pt3Ni/TiO2 octahedral alloy catalysts for the production of bio-aviation fuel via photothermal catalysis under a mild condition

Bio-aviation fuel, a carbon-neutral renewable energy carrier derived from biomass, has emerged as a promising alternative to conventional fossil-derived aviation fuels. This study prepared a series of Pt3Ni/TiO2, Pt-Ni/TiO2, Pt/TiO2, Ni/TiO2 catalysts via the hydrothermal method for the production of bio-aviation fuel by photothermal coupling catalytic hydrodeoxygenation (HDO) of fats and oils under mild conditions. The Pt3Ni/TiO2 catalyst exhibited superior catalytic performance, achieving 79.1 % selectivity toward bio-aviation fuel. This enhancement is attributed to its unique octahedral crystalline structure, reduced alloy particle size, high specific surface area, and increased acidic sites. Density functional theory (DFT) calculations using propionic acid (PA) as a model probe revealed that the Pt3Ni alloy displayed stronger PA adsorption energy compared to monometallic Pt or Ni active metals. Furthermore, oxygen vacancies (Ovs) on the TiO2 support showed preferential adsorption for both H2 and PA molecules, enhancing their dissociation and activation. However, the catalytic activity of Pt3Ni/TiO2 declined significantly after five reaction cycles, with bio-aviation fuel selectivity decreasing to 17.9 %, primarily due to carbon deposition on the catalyst surface.