Enhanced photocatalytic removal of phenol from aqueous solutions using ZnO modified with Ag

Vaiano, Vincenzo; Matarangolo, Mariantonietta; Murcia, Julie J.; Rojas, Hugo; Navı́o, J.A.; Hidalgo, M.C.

doi:10.1016/j.apcatb.2017.11.075

Cited by 428 publications

(133 citation statements)

References 50 publications

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“…Pure ZnO has a strong absorption in the ultraviolet region (400 nm), in accordance with the wide band-gap feature of ZnO semiconductor. In comparison to ZnO, Ag/ZnO exhibits an extra absorption band in the visible region, which can be assigned to the strong surface plasmon resonance of the metallic Ag nanoparticle [36]. This also confirms that the as-synthesized sample is composed of metallic Ag and ZnO.…”

Section: Introductionsupporting

confidence: 71%

“…The emission band may be due to the electron transition in various kinds of defect states [37]. It can be obviously seen that Ag/ZnO has a much lower emission intensity than bare ZnO, suggesting that the recombination of photogenerated electron-hole couples is significantly suppressed [36]. This will facilitate the process involved in the participation of the photogenerated carriers in the reaction.…”

Section: Introductionmentioning

confidence: 99%

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Enhanced Photocatalytic Ozonation of Phenol by Ag/ZnO Nanocomposites

Peng

Ming

et al. 2019

Catalysts

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Ag/ZnO nanocomposites were synthesized and applied in the photocatalytic ozonation of phenol. Their crystal, textural, morphological, optical, and electrochemical properties were investigated by XRD, Raman, SEM, TEM, UV-Vis diffuse reflectance spectroscopy (DRS), X-ray photoemission spectroscopy (XPS), and photoluminescence (PL) techniques in detail. The results indicated that silver nanoparticles were well dispersed on the surface of porous ZnO and the intimate contacts were formed at the Ag/ZnO interfaces. This prominently favored the separation and transfer of photoinduced electrons from ZnO to Ag nanoparticles for the activation of ozone to produce •OH and •O 2 − . As a result, a significant enhancement in photocatalytic ozonation of phenol was achieved over Ag/ZnO catalysts. It also showed a synergistic effect between photocatalysis and ozonation.Catalysts 2019, 9, 1006 2 of 12 pairs [20][21][22][23]. In addition, the supported metal nanoparticles can work with the semiconductor to cocatalyze chemical reactions [24][25][26]. In this study, Ag nanoparticles were employed to decorate ZnO for photocatalytic ozonation of organic pollutants by means of their unique properties. Experimentally, Ag nanoparticles were deposited onto the ZnO surface via a photochemical approach and the resultant Ag/ZnO catalysts were well investigated by XRD, Brunauer-Emmett-Teller (BET), TEM, SEM, X-ray photoemission spectroscopy (XPS), and electrochemical measurement. Phenol was chosen as a model contaminant to assess the catalytic performance. Electron paramagnetic resonance (EPR), along with quenching experiments, was conducted to probe the role of active species in the phenol removal and mineralization. Furthermore, the possible reaction mechanism over Ag/ZnO nanocomposites was proposed. Results and Discussion Catalysts Characterization

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Section: Introductionsupporting

confidence: 71%

Section: Introductionmentioning

confidence: 99%

Enhanced Photocatalytic Ozonation of Phenol by Ag/ZnO Nanocomposites

Peng

Ming

et al. 2019

Catalysts

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“…Amongst various materials, Ag‐ZnO hetero‐system has been extensively studied because of its suitability to have efficient electron transfer from metal to the semiconductor ,. The photocatalytic activity of these materials can be extended to the visible‐light region, though there are issues related to the recombination and back electron transfer process within the system .…”

Section: Introductionmentioning

confidence: 99%

Controlled Assembly of a Ternary‐Component Photocatalyst: Illustrating the Importance of Interfacial‐Integration of Ag‐ZnO‐rGO in Visible‐Light‐Induced Catalytic Activity

et al. 2019

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We demonstrate a bio‐inspired multi‐component assembly method to design oriented composite structures for application as visible‐light sensitive plasmon‐induced photocatalysts. Similar to the role of polypeptides in the formation of intricately designed structures of biominerals, we utilize spermine to simultaneously mineralize and assemble the photocatalytic system consisting of ZnO, Ag nanoparticles and reduced graphene oxide under mild reaction conditions. With an appropriately assembled interfacial structure and composition, the resulted material exhibits efficient catalytic activity under visible‐light irradiation. The activity of this ternary system is higher by more than one order compared with that for the binary and the ternary systems prepared via alternative methods. These results with detailed analyses reveal the importance of the interfacial assembly in creating synergistic interactions among the components. Furthermore, this interaction allows the photocatalyst to remain active and stable in the reaction addressing the issues pertaining to the charge recombination and photo‐corrosion known in plasmon‐induced ZnO‐based catalytic systems.

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“…In addition to preventing recombination (by sequestration of the electrons from the valence band), it provides photo-generated holes for the photocatalytic reaction [24]. The addition of silver on different semiconductors and nanocomposites transforms their specific surface and improves their photocatalytic activity and the separation of the electron-hollow pair [25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Removal of an Ethoxylated Alkylphenol by Adsorption on Zeolites and Photocatalysis with TiO2/Ag

et al. 2019

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Two advanced removal methods (adsorption and photocatalysis) were compared for the elimination of an ethoxylated alkylphenol (nonylphenol polyethylene glycol, NPEG). For the adsorption process, zeolites were used in their natural state, and the process was characterized by DRX (X-ray diffraction) and SEM-EDS (Scanning electron microscopy). The analysis of the results of the adsorption kinetics was carried out using different isotherms to interpret the removal capacity of zeolites. The Temkin kinetic model better predicted the experimental data and was satisfactorily adjusted to models of pseudo-second order (PSO). On the other hand, for photocatalysis, nano-particles of Ag (silver) were deposited on titanium oxide (TiO 2 ) Degussa-P25 by photo-deposition, and the catalyst was characterized by diffuse reflectance and SEM-EDS. The data obtained using the two removal techniques were analyzed by UV-Vis (ultraviolet-visible spectrophotometry) and total organic carbon (TOC). The kinetic data were compared. The photocatalytic process showed the highest efficiency in the removal of NPEG, corresponding to >80%, while the efficiency of the adsorption process was <60%. This was attributed to the recalcitrant and surfactant nature of NPEG.

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Enhanced photocatalytic removal of phenol from aqueous solutions using ZnO modified with Ag

Cited by 428 publications

References 50 publications

Enhanced Photocatalytic Ozonation of Phenol by Ag/ZnO Nanocomposites

Enhanced Photocatalytic Ozonation of Phenol by Ag/ZnO Nanocomposites

Controlled Assembly of a Ternary‐Component Photocatalyst: Illustrating the Importance of Interfacial‐Integration of Ag‐ZnO‐rGO in Visible‐Light‐Induced Catalytic Activity

Removal of an Ethoxylated Alkylphenol by Adsorption on Zeolites and Photocatalysis with TiO2/Ag

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