ZnO activation by using activated carbon as a support: Characterisation and photoreactivity

• Published in: Applied catalysis. A, General Vol. 364; no. 1; pp. 174 - 181
• Main Authors: PULIDO MELIAN, E, GONZALEZ DIAZ, O, DONA RODRIGUEZ, J. M, COLON, G, ARANA, J, HERRERA MELIAN, J, NAVIO, J. A, PEREZ PENA, J
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 31-07-2009; Elsevier
• Subjects: 2,4-Diclorophenol; Activated carbon; Adsorbents; Catalysis; Chemistry; Colloidal state and disperse state; Exact sciences and technology; General and physical chemistry; Phenol; Photocatalytic degradation; Photochemistry; Physical chemistry of induced reactions (with radiations, particles and ultrasonics); Porous materials; Surface physical chemistry; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; ZnO; Photocatalytic degradation; Phenol; ZnO; 2,4-Diclorophenol; Activated carbon; Modification; Binary compound; Support; Alcohol; Activation; Agglomeration; Decomposition; Porous material; Degradation; Particle; Hydroxyl group; Structure; Scanning electron microscopy; Vibration; Photocatalysis; Transition element compounds; Base; Infrared spectrometry; Heterogeneous catalysis; Pollutant; Acids; Pore; Laser; Phenols; Benzenic compound; Surface area; Catalyst; Electrons
• ISSN: 0926-860X; 1873-3875
• DOI: 10.1016/j.apcata.2009.05.042

Activated carbon loaded ZnO materials were synthesised, characterised and evaluated in the photocatalytic decomposition of phenol and 2,4-dichlorophenol. Changes in the FTIR vibration bands of the surface hydroxyl groups were recorded. Laser scattering studies showed that AC loading leads to smaller ZnO particles. BET and SEM analysis showed agglomeration of ZnO particle pores in the AC structure.
The effect of the mixing ZnO with different portions of activated carbon (AC) has been studied. The resulting catalysts were characterised and evaluated in the photocatalytic decomposition of aqueous pollutants. Changes in the catalyst colour and in the FTIR vibration bands of the surface hydroxyl groups were recorded.
νOH vibrations were shifted to lower wavenumbers as AC loading increased, demonstrating modification of the acid-base character of the catalysts. Laser scattering studies showed that AC loading leads to smaller ZnO particles. BET surface area measurements and scanning electron micrograph (SEM) analysis showed agglomeration of ZnO particle pores in the AC structure.
Results showed that in addition to a synergistic effect of the AC-ZnO combination, AC content modifies the ZnO particle properties and consequently photocatalytic behaviour. This was evident in phenol degradation experiments where changes in the concentration profiles of the catechol and hydroquinone degradation intermediates, were observed. However, the AC-ZnO catalysts were less efficient than pure ZnO in the degradation of 2,4-dichlorophenol (DCP). This seems to be due to the strong adsorption of the DCP molecule on AC, resulting in lower diffusion to the catalytic ZnO and thus a lower rate of photocatalysis.