SnIV-containing layered double hydroxides as precursors for nano-sized ZnO/SnO2 photocatalysts

• Published in: Applied catalysis. B, Environmental Vol. 84; no. 3-4; pp. 699 - 705
• Main Authors: Seftel, E.M., Popovici, E., Mertens, M., Stefaniak, E.A., Van Grieken, R., Cool, P., Vansant, E.F.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 01.12.2008; Elsevier
• Subjects: Catalysis; Charge separation; Chemistry; Exact sciences and technology; General and physical chemistry; Methyl orange; Photocatalysis; Photochemistry; Physical chemistry of induced reactions (with radiations, particles and ultrasonics); Sn4+ containing LDHs; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; ZnO/SnO2 systems; Sn4+ containing LDHs; Methyl orange; ZnO/SnO2 systems; Photocatalysis; Charge separation; Binary compound; Heat treatment; Dyes; Precursor; Crystallites; Precipitation; Raman scattering; Tin oxide; pH; Structure; Photochemical degradation; Semiconductor materials; Transition element compounds; X ray diffraction; Dispersion; Heterogeneous catalysis; Layered double hydroxide; Catalyst; Reflectance; Environmental protection
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2008.06.006

Sn4+-containing LDH was prepared using the co-precipitation method at constant pH, and characterized using X-ray diffraction, UV–vis diffuse reflectance spectroscopy and TG/DTG methods. The obtained product was further exposed to different thermal treatments in order to obtain nano-sized coupled ZnO/SnO2 systems with enhanced photocatalytic performances than the ones obtained by mixing the two semiconductor oxides. The formation of a well-defined ZnO/SnO2 system and the crystallite size, fully investigated using XRD, micro-Raman scattering and UV–vis DR techniques, were found to be influenced by the nature of the precursors and the calcination temperature. The photocatalytic activity of the ZnO/SnO2 systems, evaluated for the photodegradation of methyl orange (MO) dye, was studied as a function of the initial pH, catalyst loading and the calcination temperature. The metal dispersion supplied by layered structures proved to be an advantage when preparing coupled ZnO/SnO2 systems, the photocatalytic activity being ∼2.3 times higher comparing with the physical mixtures performances. The maximum photocatalytic activity of the coupled ZnO/SnO2 system having a layered precursor was observed when using neutral pH, at a catalyst loading of 1g/L calcined at 600°C for 4h.