Monometallic nanoparticles decorated and rare earth ions doped KTaO3/K2Ta2O6 photocatalysts with enhanced pollutant decomposition and improved H2 generation
Anna Krukowska , Grzegorz Trykowski , Wojciech Lisowski , Tomasz Klimczuk , Michał Jerzy Winiarski , Adriana Zaleska-Medynska
AbstractNew, monometallic nanoparticles (MNPs) decorated surface and rare earth (RE) ions doped lattice of perovskite-type (KTaO3)/pyrochlore-type (K2Ta2O6) photocatalysts were successfully prepared by facile hydrothermal incorporation of RE ions into KTaO3/K2Ta2O6 lattices followed by photodeposition of MNPs. The impact of noble metal type (MNPs = Au, Pt, Rh) and rare earth dopant type (RE = Er, Pr) on the physicochemical properties correlated with photoactivity of MNPs/RE-KTaO3 and MNPs/RE-K2Ta2O6 has been examined. All as-prepared photocatalysts were systematically characterized by UV–vis diffuse reflectance spectroscopy, photoluminescence emission spectroscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, fast Fourier transform, powder X-ray diffraction, and X-ray photoelectron spectroscopy. The crystal structure was presented using VESTA software. Photocatalytic activity of samples under visible light irradiation was determined by pollutant decomposition, while UV–vis induced activity was estimated by H2 generation efficiency. The experimental results suggested a synergistic effect between MNPs and RE-ions-modified KTaO3/K2Ta2O6, which resulted in greatly improved photocatalytic performance compared with that of pristine KTaO3/K2Ta2O6. Inclusion of RE ions into KTaO3/K2Ta2O6 lattices probably leads to formation of RE4f states below the conduction band levels to electron transition by lower photon excitation energy, while photoreduction of MNPs on the RE-KTaO3/RE-K2Ta2O6 surface causes localized surface plasmon resonance and activates surface by adsorption for both O2 and H2O molecules. The highest visible-light-induced photoactivity was observed for the Au/Er-KTaO3 sample (16.48%) in phenol solution degradation and for the Pt/Pr-K2Ta2O6 photocatalyst (36.13%) in gaseous toluene removal, respectively. Active species-trapping tests indicate that O2radical dot− radicals are meaningfully involved in phenol oxidation under visible light irradiation. The largest amount of H2 evaluation was observed for the Pt/Pr-K2Ta2O6 sample (93.16 µmol/min) under UV–vis irradiation, which also showed a relatively good lifetime in recycling. The present study describes noble- and rare-earth-metal-modified KTaO3/K2Ta2O6 as an advanced material in photocatalysis.
|Journal series||Journal of Catalysis, ISSN 0021-9517|
|Publication size in sheets||0.5|
|Keywords in English||perovskite KTaO3/pyrochlore K2Ta2O6, rare earth ions doping, metal nanoparticles photodeposition, vis/UV–vis photocatalytic activity, pollutant degradation/H2 generation|
|Score|| = 40.0, 02-07-2018, ArticleFromJournal|
= 45.0, 02-07-2018, ArticleFromJournal
|Publication indicators||: 2016 = 6.844 (2) - 2016=7.61 (5)|
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