Surface morphology and active sites of TiO2 for photoassisted catalysis

The main aim of this work is to discriminate the closely related adsorption and catalytic degradation processes that occur during a photocatalytic reaction. Very high-surface-area TiO2 and Pd-doped TiO2 were synthesized by microwave-assisted hydrothermal synthesis and used for degradation of methylene blue as a model pollutant dye. Thorough structural, morphological, and surface analyses of the synthesized catalysts were conducted to investigate key material properties that influence adsorption and catalytic performance. The adsorption capacity of the catalysts was determined by fitting adsorption data using the Langmuir isotherm model, and the photocatalytic activity of the synthesized samples was evaluated by periodically measuring the concentration of methylene blue as it was photocatalytically degraded under ultraviolet (UV) light. The results indicated that noble-metal incorporation compromised adsorption but favored catalytic performance.