One-Step Synthesis of Cu_xO_y/TiO₂ Photocatalysts by Laser Pyrolysis for Selective Ethylene Production from Propionic...

In an effort to produce alkenes in an energy-saving way, this study presents for the first time a photocatalytic process that allows for the obtention of ethylene with high selectivity from propionic acid (PA) degradation. To this end, TiO₂ nanoparticles (NPs) modified with copper oxides (Cu_xO_y/TiO₂) were synthetised via laser pyrolysis. The atmosphere of synthesis (He or Ar) strongly affects the morphology of photocatalysts and therefore their selectivity towards hydrocarbons (C₂H₄, C₂H₆, C₄H₁₀) and H₂ products. Specifically, Cu_xO_y/TiO₂ elaborated under He environment presents highly dispersed copper species and favours the production of C₂H₆ and H₂. On the contrary, Cu_xO_y/TiO₂ synthetised under Ar involves copper oxides organised into distinct NPs of ~2 nm diameter and promotes C₂H₄ as the major hydrocarbon product, with selectivity, i.e., C₂H₄/CO₂ as high as 85% versus 1% obtained with pure TiO₂.