Influence of Different Fuels in the Combustion Synthesis of TiO2 Photoelectrodes Produced Using the Layer-by-Layer Technique

Titanium dioxide (TiO 2 ) particles were synthesized using combustion synthesis with different fuels and immobilized onto the ITO electrode surface using the Layer-by-Layer technique. The properties of the TiO 2 were significantly influenced by the type of fuel used during synthesis (citric acid, L -alanine, glycine, or urea) and pH due to factors such as the fuel's reducing power and its complexation with the oxotitanium(IV) cation, [Ti = O] 2+ . Citric acid and L -alanine fuels formed only the anatase phase of TiO 2 , while glycine and urea formed mixtures of the anatase and brookite phases. Complete conversion to TiO 2 at lower temperatures was observed when using urea. The band gap energy exhibited a significant decrease in the obtained materials compared to bulk TiO 2 (3.2 eV). Urea and L -alanine fuels produced materials with smaller crystallite sizes and higher specific surface areas. Urea was the fuel that yielded TiO 2 photoelectrodes with the best photoelectrocatalytic for the methylene blue discoloration reaction.