Publication detail

Photocatalytic H-2 generation from aqueous ammonia solution using ZnO photocatalysts prepared by different methods

Year: 2015

Type of publication: článek v odborném periodiku

Name of source: International Journal of Hydrogen Energy

Publisher name: Pergamon-Elsevier Science Ltd.

Place: Oxford

Page from-to: 8530-8538

Titles:

Language	Name	Abstract	Keywords
cze	Fotokatalytické generování H-2 z vodného roztoku amoniaku za použití ZnO fotokatalyzátoru připraveného různými metodami	Fotokatalyzátor ZnO byl připraven dvěma způsoby: a) pomocí srážení acetátu zinku s hydroxidem sodným a následného žíhání; b) pomocí srážení acetátu zinku s hydroxidem sodným v přítomnosti UV záření a následným žíháním. Připravené nanočástice byly charakterizovány pomocí termogravimetrie, rentgenové difrakce, UV-VIS DRS, fotoluminescenční spektroskopie, transmisní elektronové mikroskopie a N-2 fyzisorpce.	produkce H2; ZnO; amoniak; fotokatalýza
eng	Photocatalytic H-2 generation from aqueous ammonia solution using ZnO photocatalysts prepared by different methods	ZnO photocatalysts were prepared by thermal annealing of zinc acetate, by precipitation reaction of zinc acetate with sodium hydroxide followed by thermal annealing and by precipitation reaction of zinc acetate with sodium hydroxide in the presence of UV irradiation followed by thermal annealing. The prepared nanoparticles were characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), UV-Vis diffuse reflectance (UV-Vis DRS) and photoluminescence (PL) spectroscopy, transmission electron microscopy (TEM) and N-2 physisorption measurements. The photocatalytic performance of these materials was investigated for H-2 evolution using aqueous ammonia media under 254 nm UV light. The H-2 evolution was compared with TiO2 Evonik P25. Beside H-2 photocatalytic generation, H-2 photochemical generation was also observed. The different used synthetic procedure leading to the formation of different defects (oxygen vacancies (Vo) and oxygen excess defects (O-i/O-zn)) in the ZnO lattice were factors influencing photocatalytic production of hydrogen. Oxygen vacancy (Vo) was recognized as defect significantly decreasing photocatalyst activity. The highest yields of hydrogen were observed in ZnO prepared by thermal annealing of zinc acetate in air. This photocatalyst possesses the lowest concentration of oxygen vacancies causing efficient trapping of electrons. Consequently higher number of electrons in conduction band was available for photocatalytic reaction.	Hydrogen production; Zinc oxide; Ammonia; Photocatalysis

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