Evaluation of SnO2 for sunlight photocatalytic decontamination of water

Aslam, Muhammad; Qamar, Muhammad Tariq; Ali, Shahid; Rehman, Ateeq Ur; Soomro, M. Tahir; Ahmed, Ikram; Ismail, Iqbal M.I.; Hameed, Abdul

doi:10.1016/j.jenvman.2018.04.042

Cited by 47 publications

(17 citation statements)

References 51 publications

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“…If the surface defect formation in the metal oxide layer is assisted by an oxygen release, such mechanisms may include oxygen-generated degradation in the perovskite layer. Alternatively, or in addition, the formation of superoxide radical anions, a well-known contribution to irreversible degradation, may arise due to the electron-transfer processes from SnO 2 . − This may be supported by an applied positive bias, which from the simulations also show a further increase in bulk defect states that do not recover even after t22h (Table ). The defects at the Spiro-OMeTAD recover at a much slower rate, which could be explained by the lack of repelling the cations back into the perovskite layer, which is otherwise supported by the applied negative bias in the OC condition.…”

Section: Results and Discussionmentioning

confidence: 94%

Bias-Dependent Dynamics of Degradation and Recovery in Perovskite Solar Cells

Prete

Khenkin

Głowienka

et al. 2021

ACS Appl. Energy Mater.

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Degradation of perovskite solar cells (PSCs) is often found to be partially or fully reversible when the cells are allowed to recover in the dark. Unlike the dynamics of degradation, knowledge about the dynamics of PSC cell recovery is very limited. Here, we demonstrate that the PSC recovery strongly depends on the electrical bias conditions during the light-induced degradation and that it can be manipulated by applying an external electrical bias during the recovery phase. Investigation of the recovery dynamics allows us to analyze the degradation mechanisms in detail. More specifically, we aged a mixed-cation mixed-halide PSC with a n-i-p structure under illumination in open-circuit (OC) or short-circuit (SC) conditions, and periodically measured their characteristics during the recovery. PSCs aged in SC degrade faster and fully recover after the light is switched off, while the performance of the cells aged in OC does not recover but instead further decreases after the light is switched off (“drop-in-dark” effect). With the use of transient photoluminescence, secondary ion mass spectrometry, and drift-diffusion-based simulations, we hypothesize that extrinsic ion migration causes the drop-in-dark effect, by forming an electron extraction barrier at the metal oxide electron transport layer. The applied bias alleviates this effect. Our results are relevant for gaining a deeper understanding of the multiple degradation mechanisms present in perovskite solar cells, and for finding a practical way to assist their recovery.

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Section: Results and Discussionmentioning

confidence: 94%

Bias-Dependent Dynamics of Degradation and Recovery in Perovskite Solar Cells

Prete

Khenkin

Głowienka

et al. 2021

ACS Appl. Energy Mater.

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“…Degradation and mineralization can occur simultaneously, thanks to the presence of superoxide radicals, accompanied by a minor route of hydroxyl radicals, which can be associated with the rapid disappearance of total organic carbon [56,57].…”

Section: Possible Routes Of 246-trichlorophenol Degradationmentioning

confidence: 99%

Activated Hydrotalcites Obtained by Coprecipitation as Photocatalysts for the Degradation of 2,4,6‐Trichlorophenol

Ramos-Ramírez

Ortega

Tzompantzi

et al. 2018

Advances in Materials Science and Engineering

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A gallery of hydrotalcite-type mesoporous materials with different Mg/Al molar ratios were synthesized by the coprecipitation method. The materials were activated by heat treatment to test their activity in the photodegradation of 2,4,6-trichlorophenol under UV light irradiation. The physicochemical properties of the different synthesized and activated materials were determined using XRD, physical adsorption/desorption of N2, FTIR, SEM, DTA, and TGA. Their banned band energy was determined by UV-Vis to identify their potential to be used as a semiconductor in catalytic photodegradation processes. The results of photodegradation tests of 2,4,6-trichlorophenol showed that hydrotalcites have a high degradation capacity, up to 100% for the catalyst of Mg/Al ratio = 2, with a high mineralization capacity of 80%. The degradation capacity of most of the catalysts tested is mainly due to the presence of holes and the formation of superoxide free radicals, which are the determining species within the degradation mechanism.

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“…The Fermi level is located near the conduction band (CB) of the catalysts in the n-type semiconductors, so that the V FB can be approximated to the CB. [36,37] Based on the evaluated band gap of 3.48 eV for SnO 2 by UV-vis result (Figure 1c), the VB of the SnO 2 appeared at 3.05 V. In the same way, the evaluated band gap for SnO 2 -Hf is 3.80 eV, the VB of the SnO 2 -Hf appeared at 3.18 V (Figure 1d). Importantly, the evaluated CB and VB professed the capacity of SnO 2 -Hf for the generation both hydroxyl ( • OH) and superoxide ( • O 2 -) radicals.…”

Section: Photocatalysts Fabrication and Characterizationsmentioning

confidence: 79%

Enhanced Reactant Activation and Transformation for Efficient Photocatalytic Acetone Degradation on SnO₂ via Hf Doping

Zhang

et al. 2021

Advanced Sustainable Systems

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Intensified photocatalytic performance through reducing the recombination of electron–hole pairs and enhancing the oxidation capacity is a key challenge in the field of photocatalytic removal of volatile organic compounds (VOCs). Acetone, as one of the emblematical contaminants VOCs, is a general solvent and widely applied in the pharmaceutical industry, contributing severely to air pollution. Most studies of photocatalysis have focused on the photocatalyst efficiency toward pollutant degradation, but the detailed mechanisms of charge separation as well as transfer and photocatalytic acetone oxidation pathways are not revealed clearly. In this work, it is found that hafnium metal doping on the n‐type semiconductor SnO2 can modify the electronic structures, restrain the recombination of electron–hole pairs, where the hafnium metal ion acts as the activation site, leading to improved oxidation ability to realize efficient acetone degradation. In addition, the specific path toward the acetone degradation is revealed by closely combined active radical detection, in situ diffuse reflectance infrared Fourier transform spectroscopy and theoretical calculation methods. It provides a new perspective about the detailed and comprehensive reaction mechanism of photocatalytic acetone degradation and carriers transfer between pollutants and photocatalysts, which is expected to promote the practical usage of photocatalytic technology for the expeditious removal VOCs.

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Evaluation of SnO2 for sunlight photocatalytic decontamination of water

Cited by 47 publications

References 51 publications

Bias-Dependent Dynamics of Degradation and Recovery in Perovskite Solar Cells

Bias-Dependent Dynamics of Degradation and Recovery in Perovskite Solar Cells

Activated Hydrotalcites Obtained by Coprecipitation as Photocatalysts for the Degradation of 2,4,6‐Trichlorophenol

Enhanced Reactant Activation and Transformation for Efficient Photocatalytic Acetone Degradation on SnO₂ via Hf Doping

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Evaluation of SnO2 for sunlight photocatalytic decontamination of water

Cited by 47 publications

References 51 publications

Bias-Dependent Dynamics of Degradation and Recovery in Perovskite Solar Cells

Bias-Dependent Dynamics of Degradation and Recovery in Perovskite Solar Cells

Activated Hydrotalcites Obtained by Coprecipitation as Photocatalysts for the Degradation of 2,4,6‐Trichlorophenol

Enhanced Reactant Activation and Transformation for Efficient Photocatalytic Acetone Degradation on SnO2 via Hf Doping

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Enhanced Reactant Activation and Transformation for Efficient Photocatalytic Acetone Degradation on SnO₂ via Hf Doping