Synergy of Ni dopant and oxygen vacancies in ZnO for efficient photocatalytic depolymerization of sodium lignosulfonate

Xu, Jie; Li, Ming; Yang, Lvye; Qiu, Jianhao; Qian, Chen; Zhang, Xiongfei; Feng, Yi; Yao, Jianfeng

doi:10.1016/j.cej.2020.125050

Cited by 71 publications

(12 citation statements)

References 52 publications

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“…These results indicate that p–n heterojunctions are formed in ZnO/NiO nanoparticles. In addition, as shown in the figure, the main peak at 530.3–530.6 eV can be allocated to the lattice oxygen of ZnO, and the signal at the higher binding energy of 532.0–532.4 eV can be attributed to the formation of oxygen vacancies on the surface [ 31 ]. As can be seen from the figure, defect states also appear on the surface of pure ZnO due to its small particle size, leading to the appearance of oxygen vacancies.…”

Section: Resultsmentioning

confidence: 99%

The Oxygen Vacancy Defect of ZnO/NiO Nanomaterials Improves Photocatalytic Performance and Ammonia Sensing Performance

Zhang

2022

Nanomaterials

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In this paper, ZnO/NiO composites rich in oxygen vacancies are prepared by the solvothermal method and reduction method. In the test, through the use of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscope (TEM), diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), and electron paramagnetic resonance (EPR), we effectively prove the existence of phase, morphology and oxygen vacancies in the material. Through the photocatalysis test and gas sensitivity test, it is found that 10% Ni doped OZN-10 has the best photocatalytic activity and gas sensitivity characteristics. The degradation rate of methylene blue (MB) was 98%. The gas sensitivity test shows that OZN-10 has good selectivity, good response performance (3000 ppm, 27,887%) and excellent response recovery time (response time: 50 s, recovery time: 5–7 s) for saturated NH3 gas at standard atmospheric pressure (101.325 KPa) and room temperature (25 °C). The synergistic effect of oxygen vacancy as the center of a trap and p–n heterojunction forming an electric potential field at the interface is explained, and the mechanism of improving photocatalysis and gas sensitivity is analyzed. This work will provide an innovative vision for dual-performance oxygen vacancy modification of heterojunctions through photocatalysis.

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Section: Resultsmentioning

confidence: 99%

The Oxygen Vacancy Defect of ZnO/NiO Nanomaterials Improves Photocatalytic Performance and Ammonia Sensing Performance

Zhang

2022

Nanomaterials

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“…The crystalline cobalt oxides on the surface of the supporting material both create and stabilize surficial and/or bulk oxygen vacancies along with preventing surface passivation. These oxygen vacancies are efficient to promote the diffusion of oxygen ions and the separation of electrons and holes, further enhancing the electronic conductivity of the catalysts . Consequently, active sites are formed by the combined effects of crystalline cobalt oxides and oxygen vacancies, significantly accelerating the charge transfer of catalysts to promote catalytic performance. , Currently, the crystalline cobalt oxide-incorporated catalysts have been extensively investigated for various applications, while the amorphous cobalt-doped catalysts with excellent catalytic performance need to be further researched to fill the knowledge gaps associated with this promising AOP catalyst.…”

Section: Introductionmentioning

confidence: 99%

Uniform Mesoporous Amorphous Cobalt-Inherent Silicon Oxide as a Highly Active Heterogeneous Catalyst in the Activation of Peroxymonosulfate for Rapid Oxidation of 2,4-Dichlorophenol: The Important Role of Inherent Cobalt in the Catalytic Mechanism

Lian

Roy

Kizilkaya

et al. 2020

ACS Appl. Mater. Interfaces

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Amorphous cobalt-inherent silicon oxide (Co-SiOx) was synthesized for the first time and employed as a highly active catalyst in the activation of peroxymonosulfate (PMS) for the rapid oxidation of 2,4-dichlorophenol (2,4-DCP). The characterization results revealed that the 0.15Co-SiOx possessed a high specific surface area of 607.95 m 2 /g with a uniform mesoporous structure (24.33 nm). The X-ray diffraction patterns indicate that the substituted cobalt atoms enlarge the unit cell parameter of the original SiO 2 , and the selected area electron diffraction pattern confirmed the amorphous nature of Co-SiOx. More bulk oxygen vacancies (O v ) existing in the Co-SiOx were identified to be one of the primary contributors to the significantly enhanced catalytic activation of PMS. The cobalt substitution both creates and stabilizes the surficial O v and forms the adequately active Co(II)−O v pairs which engine the electron transfer process during the catalytic activities. The active Co(II)−O v pairs weaken the average electronegativity of Co/Si and Co/O sites, resulting in the prevalent changes in final state energy, which is the main driving cause of the binding energy shifts in the X-ray photoelectron spectroscopy (XPS) spectra of Si and O among all samples. The increase of the relative proportion of Co(III) in the spent Co-SiOx probably causes the binding energy shifts of the Co XPS spectrum compared to that of the Co-SiOx. The amorphous Co-SiOx outperforms stable and quick 2,4-DCP degradation, achieving a much higher kinetic rate of 0.7139 min −1 at pH = 7.02 than others via sulfate radical advanced oxidation processes (AOPs), photo-Fenton AOPs, H 2 O 2 reagent AOPs, and other AOP approaches. The efficient degradation performance makes the amorphous Co-SiOx as a promising catalyst in removing 2,4-DCP or organic-rich pollutants.

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“…This is mainly attributed to the effective adjustment of the dielectric constant of MnO 2 with Ni doping. Additionally, Ni doping could induce a valence state change in the material, which is likely to induce a large number of vacancy defects to balance the valence state. − It is worth mentioning that oxygen vacancies are closely related to the microwave absorption characteristics in terms of improving electrical conductivity and enhancing polarization relaxation. , Compared with the MnO 2 particles and nanosheets, MnO 2 nanorods are conducive to construct a three-dimensional conductive network, thereby enhancing the conductance loss. A previous study has found that the incorporation of MnO 2 nanorods can tune the dielectric performance of Ti 3 C 2 T x MXene to show controllable microwave absorption .…”

Section: Introductionmentioning

confidence: 99%

Ni Doping in MnO₂/MXene (Ti₃C₂T_x) Composites to Modulate the Oxygen Vacancies for Boosting Microwave Absorption

Huang

et al. 2022

ACS Appl. Electron. Mater.

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Endowing composites with defects such as oxygen vacancies is an easy and effective strategy to determine the physical and chemical properties of nanomaterials. The influence of defects on microwave absorption remains a very open question. Herein, MnO2/Ti3C2T x MXene composites are self-assembled, demonstrating the boosting of microwave absorption through Ni doping in MnO2 to modulate the oxygen vacancies. The Ni-doped MnO2 (Ni–MnO2) nanorods with diameters of about 40 nm are dispersed on the surface and interlay of MXene. As expected, the reflection loss (RL) value and effective absorption bandwidth (EAB) of Ni–MnO2/MXene composites are −55.9 dB and 6.32 GHz, which are greatly enhanced over pure MnO2/MXene with −18.8 dB and 4.56 GHz. This excellent microwave absorption is mainly attributed to the optimized impedance matching in Ni–MnO2/MXene composites. In addition, the random distribution of MnO2 nanorods and MXene layers will form a conductive network, leading to the inducing microcurrent to form conduction losses. Moreover, interfacial polarization between layered MXene and Ni–MnO2 and dipole polarization induced by oxygen defects yield a strongly dielectric loss. Thus, our work provides a novel principle of modulation in oxygen vacancies to develop efficient MXene-based multicomponent composites for electromagnetic wave absorption.

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Synergy of Ni dopant and oxygen vacancies in ZnO for efficient photocatalytic depolymerization of sodium lignosulfonate

Cited by 71 publications

References 52 publications

The Oxygen Vacancy Defect of ZnO/NiO Nanomaterials Improves Photocatalytic Performance and Ammonia Sensing Performance

The Oxygen Vacancy Defect of ZnO/NiO Nanomaterials Improves Photocatalytic Performance and Ammonia Sensing Performance

Uniform Mesoporous Amorphous Cobalt-Inherent Silicon Oxide as a Highly Active Heterogeneous Catalyst in the Activation of Peroxymonosulfate for Rapid Oxidation of 2,4-Dichlorophenol: The Important Role of Inherent Cobalt in the Catalytic Mechanism

Ni Doping in MnO₂/MXene (Ti₃C₂T_x) Composites to Modulate the Oxygen Vacancies for Boosting Microwave Absorption

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Synergy of Ni dopant and oxygen vacancies in ZnO for efficient photocatalytic depolymerization of sodium lignosulfonate

Cited by 71 publications

References 52 publications

The Oxygen Vacancy Defect of ZnO/NiO Nanomaterials Improves Photocatalytic Performance and Ammonia Sensing Performance

The Oxygen Vacancy Defect of ZnO/NiO Nanomaterials Improves Photocatalytic Performance and Ammonia Sensing Performance

Uniform Mesoporous Amorphous Cobalt-Inherent Silicon Oxide as a Highly Active Heterogeneous Catalyst in the Activation of Peroxymonosulfate for Rapid Oxidation of 2,4-Dichlorophenol: The Important Role of Inherent Cobalt in the Catalytic Mechanism

Ni Doping in MnO2/MXene (Ti3C2Tx) Composites to Modulate the Oxygen Vacancies for Boosting Microwave Absorption

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Ni Doping in MnO₂/MXene (Ti₃C₂T_x) Composites to Modulate the Oxygen Vacancies for Boosting Microwave Absorption