Nitrogen-containing TiO2 photocatalysts. Part 2. Photocatalytic behavior under sunlight excitation

• Published in: Applied catalysis. B, Environmental Vol. 65; no. 3-4; pp. 309 - 314
• Main Authors: BELVER, C, BELLOD, R, STEWART, S. J, REQUEJO, F. G, FERNANDEZ-GARCIA, M
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier 06.06.2006
• Subjects: Catalysis; Chemistry; Colloidal state and disperse state; Emulsions. Microemulsions. Foams; Exact sciences and technology; General and physical chemistry; Photochemistry; Physical chemistry of induced reactions (with radiations, particles and ultrasonics); Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Anatase; Impurity; DRIFTS; Photocatalysis; Doping; Transition element compounds; Pollutant mineralization and degradation; XAS; Nitrogen; Visible light absorption; Microemulsion method; TiO2 Anatase materials; Degradation; Infrared spectrometry; Heterogeneous catalysis; Pollutant; N-doping and impurity; Mineralization; Light absorption; Microemulsion; Solar radiation; Titanium oxide; Environmental protection
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2006.02.016

A series of nanosized N-containing TiO2-based materials with Anatase-type structure and synthesized by a microemulsion method were tested in the photocatalytic degradation of methylcyclohexene, a representative example of volatile organic compound (VOC) present in urban atmospheres. A combined diffuse reflectance infrared (DRIFTS) and X-ray absorption (XAS) spectroscopic study allows to analyze the nature and number of N-containing species and other defects (particularly oxygen vacancies) present in the solid catalysts. The structural characterization was used to interpret the UV-vis spectra of the solids and the resulting joint information allows to rationalize the photocatalytic activity differences observed through the samples under sunlight-type excitation. We founded that our samples contain substitutional and interstitial N-containing impurities and a significant number of oxygen vacancies. Photocatalytic activity is correlated with an optimum of oxygen vacancies, above and below which a decrease of the steady state reaction rate is observed. The physico-chemical bases of this behavior are discussed on the light of the above mentioned experimental results.