Synthesis of novel Ag/Ag2O heterostructures with solar full spectrum (UV, visible and near-infrared) light-driven photocatalytic activity and enhanced photoelectrochemical performance

Yang, Hongru; Tian, Jian; Li, Tong; Cui, Hongzhi

doi:10.1016/j.catcom.2016.09.013

Cited by 70 publications

(21 citation statements)

References 25 publications

(27 reference statements)

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“…XRD and XPS data indicate that Ag(I) was reduced, yielding Ag(0), during the light-induced bleaching reaction of MB in the presence of the composite TC 41. A stabilization of Ag 2 O by metallic silver, as claimed by several authors [9][10][11][12]20,29], was not observed. No XRD peaks that can be attributed Ag 2 O, were observed after two experimental runs of the composite.…”

Section: Bleaching Of Methylene Bluementioning

confidence: 62%

“…The two strongest peaks of Ag 2 O become more prominent, with the Ag 2 O mass ratio increasing from TM 14 to TM 41. The small diffraction peaks situated at 44.4 • , 64.2 • , and 77.5 • are indexed to the (200), (200), and (311) plane of metallic Ag(0) (JCPDS 04-0783) [20]. The strongest peak of Ag(111) might likely be masked by the TiO 2 peak at 2θ = 38 • .…”

Section: Characterization Of the Prepared Materialsmentioning

confidence: 99%

“…It is well known that Ag 2 O is sensitive to light and decomposes under illumination. However, it has been suggested that Ag(0) being present in Ag/Ag 2 O acts as an electron sink and accepts the conduction band electron of Ag 2 O, thus inhibiting the reduction of Ag + and stabilizing the Ag 2 O [9,10,12,20]. However, the possibility cannot be excluded that Ag + is reduced during the processes given in the Equations (2)−( 5), yielding Ag(0), since no other suitable electron acceptor is available.…”

Section: Ag2omentioning

confidence: 99%

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Ag/Ag2O as a Co-Catalyst in TiO2 Photocatalysis: Effect of the Co-Catalyst/Photocatalyst Mass Ratio

et al. 2018

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Mixtures and composites of Ag/Ag2O and TiO2 (P25) with varying mass ratios of Ag/Ag2O were prepared, employing two methods. Mechanical mixtures (TM) were obtained by the sonication of a suspension containing TiO2 and Ag/Ag2O. Composites (TC) were prepared by a precipitation method employing TiO2 and AgNO3. Powder X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) confirmed the presence of Ag(0) and Ag2O. The activity of the materials was determined employing methylene blue (MB) as the probe compound. Bleaching of MB was observed in the presence of all materials. The bleaching rate was found to increase with increasing amounts of TiO2 under UV/vis light. In contrast, the MB bleaching rate decreased with increasing TiO2 content upon visible light illumination. XRD and XPS data indicate that Ag2O acts as an electron acceptor in the light-induced reaction of MB and is transformed by reduction of Ag+, yielding Ag(0). As a second light-induced reaction, the evolution of molecular hydrogen from aqueous methanol was investigated. Significant H2 evolution rates were only determined in the presence of materials containing more than 50 mass% of TiO2. The experimental results suggest that Ag/Ag2O is not stable under the experimental conditions. Therefore, to address Ag/Ag2O as a (photo)catalytically active material does not seem appropriate.

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Section: Bleaching Of Methylene Bluementioning

confidence: 62%

Section: Characterization Of the Prepared Materialsmentioning

confidence: 99%

Section: Ag2omentioning

confidence: 99%

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Ag/Ag2O as a Co-Catalyst in TiO2 Photocatalysis: Effect of the Co-Catalyst/Photocatalyst Mass Ratio

et al. 2018

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“…According to the Mott–Schottky equation, a linear relationship of C −2 vs. V can be observed (Fig. 8a and b) and the intercepts of the straight lines with the potential axis indicate the V fb values of P25 and (NH 4 ) x WO 3 are −0.24 V vs NHE and −0.55 V vs NHE54, thus the CB of P25 and (NH 4 ) x WO 3 are −0.44 V vs NHE and −0.75 V vs NHE, respectively55. Furthermore, combining with the bandgap energy of P25 (~3.05 eV) and (NH 4 ) x WO 3 (~2.67 eV) as displayed in Fig.…”

Section: Resultsmentioning

confidence: 85%

A P25/(NH4)xWO3 hybrid photocatalyst with broad spectrum photocatalytic properties under UV, visible, and near-infrared irradiation

Yang

Liu

et al. 2017

Sci Rep

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In this study, a series of hybrid nanostructured photocatalysts P25/(NH4)xWO3 nanocomposites with the average crystallite size of P25 and (NH4)xWO3 of the sample was calculated to be about 30 nm and 130 nm, were successfully synthesized via a simple one-step hydrothermal method. The as-obtained samples was characterized by transmission electron microscopy (TEM), which implies that the P25/(NH4)xWO3 nanocomposites are fabricated with favourable nanosizd interfacial. The XPS results confirmed that the obtained sample consists of mixed chemical valences of W5+ and W6+, the low-valance W5+ sites could be the origin of NIR absorption. As revealed by optical absorption results, P25/(NH4)xWO3 nanocomposites possess high optical absorption in the whole solar spectrum of 200–2500 nm. Benefiting from this unique photo-absorption property and the synergistic effect of P25 and (NH4)xWO3, broad spectrum response photocatalytic activities covering UV, visible and near infrared regions on degradation of Rhodamine B have been realized by P25/(NH4)xWO3 nanocomposites. Meanwhile, the stability of photocatalysts was examined by the XRD and XPS of the photocatalysts after the reaction. The results show that P25/(NH4)xWO3 photocatalysts has a brilliant application prospect in the energy utilization to solve deteriorating environmental issues.

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“…The Ag 3d 5/2 peak is divided into two different peaks at 368.6 and 368.1 eV, and the Ag 3d 3/2 peak is divided into 374.6 and 374.1 eV, respectively. The peaks at 368.6 and 374.6 eV are attributed to Ag, whereas the peaks at 368.1 and 374.1 eV are attributed to Ag + in Ag 2 O, and the two pairs of separated silver peaks show a difference of D = 6 eV [21]. The molar content of the surface metallic Ag is calculated to be 11.2 wt% of the total silver element in Ag@Ag 2 O-G2 according to the areas of divided peaks (as shown in Figure 2b).…”

Section: Catalyst Characterizationmentioning

confidence: 99%

The Roles of Graphene and Ag in the Hybrid Ag@Ag2O-Graphene for Sulfamethoxazole Degradation

Zou

Deng

2018

Catalysts

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Ag@Ag 2 O-graphene (Ag@Ag 2 O-G) with different concentrations of graphene was synthesized using a facile in situ precipitation method. The photocatalysts were characterized by field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectra (DRS). The antibioticsulfamethoxazole (SMX) degradationunder simulated solar light and visible light irradiationwas investigated to evaluate photocatalytic performance. The composite photocatalyst Ag@Ag 2 O-G with 2.5 wt% graphene presented the highest activity among all the prepared composite photocatalysts. The coupling of graphene and Ag 0 increased the photocatalyticactivity and stability of pure Ag 2 O. Under higher SMX concentrations, the adsorption, not the photocatalytic ability, playeda crucial role during the SMX removal process. On the basis of the characterization and reactive oxygen species (ROS) scavenging experiments, a separation and transfer mechanism of photogenerated carriers was proposed. In the photocatalytic degradation of SMX, the major active species wereidentified as photogenerated holes; photogenerated electrons in the conduction band (CB) of Ag 2 O could not transfer to graphene through Ag 0 due to the more negative reduction potential of graphene. This is an important result regardinggraphene and Ag 0 roles which isdifferent from that for the photocatalytic degradation of dyes. This researchmay provide new insights into photocatalytic processes for the degradation of non-dye pollutants bycomposite materials to guidethe design of highly efficient reaction systems.

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Synthesis of novel Ag/Ag2O heterostructures with solar full spectrum (UV, visible and near-infrared) light-driven photocatalytic activity and enhanced photoelectrochemical performance

Cited by 70 publications

References 25 publications

Ag/Ag2O as a Co-Catalyst in TiO2 Photocatalysis: Effect of the Co-Catalyst/Photocatalyst Mass Ratio

Ag/Ag2O as a Co-Catalyst in TiO2 Photocatalysis: Effect of the Co-Catalyst/Photocatalyst Mass Ratio

A P25/(NH4)xWO3 hybrid photocatalyst with broad spectrum photocatalytic properties under UV, visible, and near-infrared irradiation

The Roles of Graphene and Ag in the Hybrid Ag@Ag2O-Graphene for Sulfamethoxazole Degradation

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