Structural disorder controlled oxygen vacancy and photocatalytic activity of spinel-type minerals: A case study of ZnFe2O4

Li, Yanzhang; Xu, Xiaoming; Ding, Cong; Chen, Ning; Ding, Haiyang; Lu, Anhuai

doi:10.1016/j.chemgeo.2018.11.022

Cited by 69 publications

(47 citation statements)

References 85 publications

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“…Indeed, it is well‐known that the presence of oxygen vacancies cause the appearance of trap states that lie inside the band gap which are actively involved in the emission characteristics of ZFO and related oxides. [ 43,44 ] Note that commonly oxygen vacancies are artificially induced in ZFO to improve the electron doping density. [ 18,20 ] In addition, the PL deactivation kinetics were further assessed by monitoring the PL decay at 575 nm.…”

Section: Resultsmentioning

confidence: 99%

Spectroelectrochemical and Chemical Evidence of Surface Passivation at Zinc Ferrite (ZnFe₂O₄) Photoanodes for Solar Water Oxidation

Liu

Meng

Yao

et al. 2021

Adv Funct Materials

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Recent advances in low‐cost manufacturing as well as in bulk/interface engineering have positioned zinc ferrite (ZnFe2O4, ZFO) in the spotlight as a candidate material for solar water oxidation. However, the severe recombination at the reactive interface remains as the main source of the poor onset potential. Although catalytic overlayers have shown to override, at least partially, the surface recombination, passivating‐only coatings are barely explored despite holding the key to specifically suppress the recombination. Here, a sub‐nanometer Al2O3 layer is conformally deposited onto nanostructured ZFO, leading to a 100 mV shift in the onset potential reaching 0.80 V versus reversible hydrogen electrode (RHE) and a fourfold photocurrent increase at 1.0 V versus RHE. The passivation‐only effect of Al2O3 is confirmed by the slowing down of the surface recombination detected by intensity‐modulated photocurrent spectroscopy and by the transient photovoltage and photoluminescence experiments. Further characterization of the chemical states at the reactive interface reveals that the partial filling of the surface oxygen vacancies and the formation of a Zn2+–Al3+ Lewis adduct are potentially involved in the surface passivation. This study not only demonstrates that Al2O3 improves ZFO's onset potential but also sheds light on the up until now unknown surface passivation mechanism.

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Section: Resultsmentioning

confidence: 99%

Spectroelectrochemical and Chemical Evidence of Surface Passivation at Zinc Ferrite (ZnFe₂O₄) Photoanodes for Solar Water Oxidation

Liu

Meng

Yao

et al. 2021

Adv Funct Materials

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“…The signal at g = 2.232 for Fe 3+ ion in the octahedral site of spinel ferrite was not observed. The signal was masked by the signal at g = 2.001, which could be due to the effect of calcination of ferrite photocatalyst at 700 °C 31 .…”

Section: Resultsmentioning

confidence: 99%

Photocatalytic Degradation of Organic Pollutants over MFe2O4 (M = Co, Ni, Cu, Zn) Nanoparticles at Neutral pH

Gupta

Ghaffari

Kim

et al. 2020

Sci Rep

160

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in this study, we report a surfactant-mediated synthesis of ferrites (Mfe 2 o 4 : M = co, ni, cu, Zn) using the co-precipitation-oxidation method. The band gap calculated from UV-Visible diffuse reflectance spectra were found in the range of 1.11-1.81 eV. These ferrite nanocatalysts were studied for the photocatalytic degradation of multiple organic dyes in a 32 W UV-C/H 2 o 2 system. All the four ferrites showed an excellent dye degradation rate in the range of 2.065-2.417 min −1 at neutral pH. in the optimized condition, NiF was found to degrade 89%, 92%, 93%, and 78% of methylene blue, methyl orange, bromo green, and methyl red, respectively within 1 min of UV-irradiation. A 40% TOC removal was recorded after 5 min of degradation reaction, which increased to 60% after 50 min. Mechanism elucidated by scavenger studies and fluorescence spectroscopy revealed that • oH and holes were the primary reactive radicals responsible for the degradation process. ferrite photocatalysts showed an insignificant performance loss in seven consecutive cycles. The photocatalyst was found efficient in the presence of a high concentration of salts. thus, it was concluded that these photocatalysts are highly suitable for the remediation of dye-contaminated wastewater. The ever-increasing population, coupled with rapid urbanization and industrialization, have deteriorated the quality of life. Excessive contamination of water bodies could be a severe threat to both human beings and other life forms. Organic dyes are considered as one of the major pollutants discharged into the environment by textile, printing, food, and leather industries 1. Though a large segment of these synthetic dyes is non-toxic or less toxic, their presence in water increases the oxygen demand, which in turn affects aquatic animals 2. Among the dyes consumed in industries, up to 70% belong to azo dye family (those with azo-functional group "-N = N-"). Azo dyes have genotoxic, mutagenic, and carcinogenic effects on living beings 3. Some of the azo dyes are known to be carcinogenic in the non-cleaved state, and for many of the azo dyes, their cleaved products such as benzidine are known to induce tumors 4. Conventional biological, chemical, and physical methods like adsorption 5,6 , chemical precipitation 7 , and microbial degradation 8 have been established for the remediation of dye-contaminated wastewater. The practical application of these processes suffers due to high operational cost, sludge production, or formation of secondary pollutants. For a complete or partial degradation of organic dyes (into non-toxic byproducts), degradation by adopting the photocatalytic process is one of the viable options. In recent years, advanced oxidation processes based on the generation of highly reactive hydroxyl radicals have gained momentum for the degradation of toxic organic pollutants 9. Though the Fenton process is easier to operate, it suffers badly due to a slow regeneration of Fe 2+ ions 10. Thus, the ultraviolet radiation or electrochemical method is generally cou...

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“…Note that the peaks at 530 and 532 eV are assigned to lattice oxygen (O L , O 2− ) and non‐lattice oxygen (O NL ) (Li et al ., 2019). The O NL may be attributed to adsorbed O species, including OH − , CO, and OCO (Li et al ., 2019). O 1s XPS spectra (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Furthermore, since the single OO bond in H 2 O 2 is much weaker than the OO double bond in O 2 , back‐donation of localized electrons after the adsorption of H 2 O 2 on O NL seems to induce the catalytic dissociation of H 2 O 2 to generate HO • (Li et al ., 2017). The association of Vo + with the splitting of H 2 O 2 is the result of it being occupied by adsorbed adventitious O species (e.g., OH − ) (Li et al ., 2019; Wang et al ., 2019). The hydroxylated surface inevitably benefits the following reactions (Eqs and ) and increases the yield of HO • :

{Vo}^{+} + e^{-} = Vo

Vo ((), {normalh}^{+}) + {OH}^{-} = {HO}^{•}

Thus, the peroxidase‐like catalytic activity of the Fe‐bearing nanoparticles may reside in the presence of Vo that can serve as electron acceptors and donors to facilitate charge transfer in H 2 O 2 (Li et al ., 2017):…”

Section: Discussionmentioning

confidence: 99%

“…Recent studies have shown that the catalytic activity of biogenic iron minerals may be attributable to the chemistry of either Fe (Melton et al ., 2014; Du et al ., 2019; Yu et al ., 2019) or surface oxygen anions (Mueller et al ., 2015; Li et al ., 2019; Wang et al ., 2019). Iron is the fourth most abundant element in the Earth's crust and occurs primarily as the ferrous [Fe(II)] or ferric [Fe(III)] forms (Melton et al ., 2014; Kappler et al ., 2015; Winkler et al ., 2018).…”

Section: Introductionmentioning

confidence: 99%

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Intrinsic enzyme‐like activity of magnetite particles is enhanced by cultivation with Trichoderma guizhouense

Chi

Zhao

Chen

et al. 2020

Environmental Microbiology

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Summary Fungal–mineral interactions can produce large amounts of biogenic nano‐size (~ 1–100 nm) minerals, yet their influence on fungal physiology and growth remains largely unexplored. Using Trichoderma guizhouense NJAU4742 and magnetite (Mt) as a model fungus and mineral system, we have shown for the first time that biogenic Mt nanoparticles formed during fungal–mineral cultivation exhibit intrinsic peroxidase‐like activity. Specifically, the average peroxidase‐like activity of Mt nanoparticles after 72 h cultivation was ~ 2.4 times higher than that of the original Mt. Evidence from high resolution X‐ray photoelectron spectroscopy analyses indicated that the unique properties of magnetite nanoparticles largely stemmed from their high proportion of surface non‐lattice oxygen, through occupying surface oxygen‐vacant sites, rather than Fe redox chemistry, which challenges conventional Fenton reaction theories that assume iron to be the sole redox‐active centre. Nanoscale secondary ion mass spectrometry with a resolution down to 50 nm demonstrated that a thin (< 1 μm) oxygen‐film was present on the surface of fungal hyphae. Furthermore, synchrotron radiation‐based micro‐FTIR spectra revealed that surface oxygen groups corresponded mainly to organic OH, mineral OH and carbonyl groups. Together, these findings highlight an important, but unrecognized, catalytic activity of mineral nanoparticles produced by fungal–mineral interactions and contribute substantially to our understanding of mineral nanoparticles in natural ecosystems.

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Structural disorder controlled oxygen vacancy and photocatalytic activity of spinel-type minerals: A case study of ZnFe2O4

Cited by 69 publications

References 85 publications

Spectroelectrochemical and Chemical Evidence of Surface Passivation at Zinc Ferrite (ZnFe₂O₄) Photoanodes for Solar Water Oxidation

Spectroelectrochemical and Chemical Evidence of Surface Passivation at Zinc Ferrite (ZnFe₂O₄) Photoanodes for Solar Water Oxidation

Photocatalytic Degradation of Organic Pollutants over MFe2O4 (M = Co, Ni, Cu, Zn) Nanoparticles at Neutral pH

Intrinsic enzyme‐like activity of magnetite particles is enhanced by cultivation with Trichoderma guizhouense

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Structural disorder controlled oxygen vacancy and photocatalytic activity of spinel-type minerals: A case study of ZnFe2O4

Cited by 69 publications

References 85 publications

Spectroelectrochemical and Chemical Evidence of Surface Passivation at Zinc Ferrite (ZnFe2O4) Photoanodes for Solar Water Oxidation

Spectroelectrochemical and Chemical Evidence of Surface Passivation at Zinc Ferrite (ZnFe2O4) Photoanodes for Solar Water Oxidation

Photocatalytic Degradation of Organic Pollutants over MFe2O4 (M = Co, Ni, Cu, Zn) Nanoparticles at Neutral pH

Intrinsic enzyme‐like activity of magnetite particles is enhanced by cultivation with Trichoderma guizhouense

Contact Info

Product

Resources

About

Spectroelectrochemical and Chemical Evidence of Surface Passivation at Zinc Ferrite (ZnFe₂O₄) Photoanodes for Solar Water Oxidation

Spectroelectrochemical and Chemical Evidence of Surface Passivation at Zinc Ferrite (ZnFe₂O₄) Photoanodes for Solar Water Oxidation