Grey Fe-CeO2-σ for boosting photocatalytic ozonation of refractory pollutants: Roles of surface and bulk oxygen vacancies

Chen, Xixi; Zhan, Shujuan; Chen, Dingsheng; He, Chun; Tian, Shuanghong; Xiong, Ya

doi:10.1016/j.apcatb.2021.119928

Cited by 64 publications

(21 citation statements)

References 62 publications

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“…In addition to the F 2g peak, the new peak at ∼590 to 600 cm −1 corresponding to the OV-induced band (D band) was observed. 46 The peak intensity ratio of I D /I F2g increases from ∼1.26 to ∼1.86 due to the Co doping, confirming the increase of more abundant OVs in the Co-CeO 2− OV plate. 38,73 The existence of enriched OVs in samples could also be verified by the EPR spectra.…”

Section: ■ Results and Discussionmentioning

confidence: 72%

“…Concerning the light utilization and the charge flow, it was essential to tune the electronic structures of semiconductors through defect engineering. Oxygen vacancies (OVs) were one of the most commonly and widely studied defects in transition metal oxides (TMOs). − A number of OV-engineered TMOs, such as TiO 2 , SnO 2 , and WO 3 , have been demonstrated to show the effective regulation of the light absorption to a visible region. − In particular, the CeO 2 with rich OVs was widely used in photocatalysis, but its photocatalytic performance was still unsatisfactory due to severe carrier recombination. − As an effective strategy for electronic structure modulation of the catalysts, heteroatom doping offers another effective strategy to promote the catalytic performance of catalysts. − It is reported that the heterometal doping could create OVs and narrow the semiconductor electronic band gap, which could significantly broaden the light response range and also serve as reactive sites to enhance the photogenerated carrier separation efficiency. − For example, Cu was incorporated into SnS 2 and favored introducing sulfur vacancies, thus providing a wider response range of visible light . Mi et al found that Fe(III) doping could generate OVs in BiOCl ultrathin nanosheets, which extends the light absorption range and promotes the interface charge transfer .…”

Section: Introductionmentioning

confidence: 99%

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Dopant and Defect Doubly Modified CeO₂/g-C₃N₄ Nanosheets as 0D/2D Z-Scheme Heterojunctions for Photocatalytic Hydrogen Evolution: Experimental and Density Functional Theory Studies

Zhang

Guo

Zhang

et al. 2021

ACS Sustainable Chem. Eng.

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Exploring novel 2D heterojunction photocatalysts with a wide spectral response and high active site exposure has been a huge challenge. A small-sized catalyst with high dispersibility has been considered an ideal model for maximizing active sites and increasing atomic efficiency. Herein, the 0D/2D Z-scheme heterojunction was designed by in situ solvothermal and subsequent calcination in air by integrating dopant and defect doubly modified CeO2 nanodots and g-C3N4 nanosheets (CNNS). Ultrafine cobalt-doped CeO2 nanodots (≈4 to 5 nm) with enriched oxygen vacancies (Co-CeO2–OVs) were uniformly and tightly anchored on the surface of CNNS to form a heterojunction. The density functional theory (DFT) calculations confirmed that cobalt dopants and oxygen vacancies form impurity energy states at the top of a valence band, thus narrowing the band gap. The optimized 0D/2D heterojunction showed a remarkable hydrogen production rate of ∼203.6 μmol/h, which was approximately 4.9- and 30.8-fold higher than that of CNNS (∼41.2 μmol/h) and CeO2 (∼6.6 μmol/h), respectively. Moreover, a large quantum yield of ∼8.94% was achieved at 420 nm. The 0D/2D heterojunction with a larger intimate area provided abundant reactive active sites and strong electron interactions to excite photogenerated carrier dynamics, and the doping and defect engineering could expand the light response range by regulating the electronic band structure. Strong evidence provided by experimental results and DFT calculations proved the Z-scheme charge transfer pathway. This work not only provided a novel approach to integrate 0D nanodots and 2D nanosheets for the formation of intimate Z-scheme heterointerfaces but also deepened the understanding of the dopant–defect synergistic modification to optimize the band structure and electronic structures for high-efficient solar energy capture and conversion.

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Section: ■ Results and Discussionmentioning

confidence: 72%

Section: Introductionmentioning

confidence: 99%

Dopant and Defect Doubly Modified CeO₂/g-C₃N₄ Nanosheets as 0D/2D Z-Scheme Heterojunctions for Photocatalytic Hydrogen Evolution: Experimental and Density Functional Theory Studies

Zhang

Guo

Zhang

et al. 2021

ACS Sustainable Chem. Eng.

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“…Radović et al synthesised ceria materials with up to 5 mol% iron by crystallisation from aqueous ammonia solution, and optical properties were studied by spectroscopic ellipsometry [77]. Fe-substituted CeO 2 prepared from nitrate salts in aqueous ammonia was found to have a high level of oxide vacancies useful for photocatalytic ozonation [78]. Recently, Fe-substituted ceria has been examined for use in rechargeable lithium batteries: Ce 0.9 Fe 0.1 O 2 was prepared by a simple hydrothermal reaction of nitrates salts in aqueous sodium hydroxide, and its behaviour towards lithium insertion and removal was tested [79].…”

Section: Transition Metal-substituted Ceriasmentioning

confidence: 99%

Solvothermal Synthesis Routes to Substituted Cerium Dioxide Materials

et al. 2021

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We review the solution-based synthesis routes to cerium oxide materials where one or more elements are included in place of a proportion of the cerium, i.e., substitution of cerium is performed. The focus is on the solvothermal method, where reagents are heated above the boiling point of the solvent to induce crystallisation directly from the solution. This yields unusual compositions with crystal morphology often on the nanoscale. Chemical elements from all parts of the periodic table are considered, from transition metals to main group elements and the rare earths, including isovalent and aliovalent cations, and surveyed using the literature published in the past ten years. We illustrate the versatility of this synthesis method to allow the formation of functional materials with applications in contemporary applications such as heterogeneous catalysis, electrodes for solid oxide fuel cells, photocatalysis, luminescence and biomedicine. We pick out emerging trends towards control of crystal habit by use of non-aqueous solvents and solution additives and identify challenges still remaining, including in detailed structural characterisation, the understanding of crystallisation mechanisms and the scale-up of synthesis.

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“…This induces the generation of more reactive oxygen species (ROS), such as superoxide (O2 •− ) and hydroxyl radical ( • OH) (E 0 = 2.8 eV) via photo-generated holes and ozonide ion radical ( • O3 − ) ( • O3/ • O3 − , 1.6 eV) mediated pathway [2,3]. Therefore, PhOx can overcome the drawback of the slow reaction rate of photocatalysis process and the low mineralization of ozonation system to improve the removal efficiency of pollutants [4]. Recently, the development of efficient and robust bifunctional catalysts driven by solar radiation in the application of wastewater treatment has attracted considerable attention.…”

Section: Introductionmentioning

confidence: 99%

Insights into the photocatalytic ozonation over Ag2O-ZnO@g-C3N4 composite: Cooperative structure, degradation performance, and synergistic mechanisms

Liu

Shi

Sans

et al. 2022

Journal of Environmental Chemical Engineering

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Grey Fe-CeO2-σ for boosting photocatalytic ozonation of refractory pollutants: Roles of surface and bulk oxygen vacancies

Cited by 64 publications

References 62 publications

Dopant and Defect Doubly Modified CeO₂/g-C₃N₄ Nanosheets as 0D/2D Z-Scheme Heterojunctions for Photocatalytic Hydrogen Evolution: Experimental and Density Functional Theory Studies

Dopant and Defect Doubly Modified CeO₂/g-C₃N₄ Nanosheets as 0D/2D Z-Scheme Heterojunctions for Photocatalytic Hydrogen Evolution: Experimental and Density Functional Theory Studies

Solvothermal Synthesis Routes to Substituted Cerium Dioxide Materials

Insights into the photocatalytic ozonation over Ag2O-ZnO@g-C3N4 composite: Cooperative structure, degradation performance, and synergistic mechanisms

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Grey Fe-CeO2-σ for boosting photocatalytic ozonation of refractory pollutants: Roles of surface and bulk oxygen vacancies

Cited by 64 publications

References 62 publications

Dopant and Defect Doubly Modified CeO2/g-C3N4 Nanosheets as 0D/2D Z-Scheme Heterojunctions for Photocatalytic Hydrogen Evolution: Experimental and Density Functional Theory Studies

Dopant and Defect Doubly Modified CeO2/g-C3N4 Nanosheets as 0D/2D Z-Scheme Heterojunctions for Photocatalytic Hydrogen Evolution: Experimental and Density Functional Theory Studies

Solvothermal Synthesis Routes to Substituted Cerium Dioxide Materials

Insights into the photocatalytic ozonation over Ag2O-ZnO@g-C3N4 composite: Cooperative structure, degradation performance, and synergistic mechanisms

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Dopant and Defect Doubly Modified CeO₂/g-C₃N₄ Nanosheets as 0D/2D Z-Scheme Heterojunctions for Photocatalytic Hydrogen Evolution: Experimental and Density Functional Theory Studies

Dopant and Defect Doubly Modified CeO₂/g-C₃N₄ Nanosheets as 0D/2D Z-Scheme Heterojunctions for Photocatalytic Hydrogen Evolution: Experimental and Density Functional Theory Studies