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268 results on '"Zhang, Kunfeng"'

55. Visible‐light‐driven photocatalytic degradation of antibiotics by newly molding g‐C3N4/graphitized biochar composites.

Author

Chen, Hanyu, Fang, Yanying, Duan, Peiyu, Zhang, Xueqi, and Zhang, Kunfeng

Subjects
PHOTODEGRADATION, RHODAMINE B, ANTIBIOTICS, BAND gaps, VISIBLE spectra, PHOTOCATALYSTS
Abstract

Newly molding g‐C3N4/graphitized biochar (g‐C3N4/GSBC) molding composites photocatalytic material with superior photocatalytic activity were successfully synthesized by the impregnation‐roasting process. The photocatalytic behavior of g‐C3N4/GSBC was assessed in the photocatalytic degradation of antibiotic pollutants, including sulfamethoxazole(SMZ), ciprofloxacin(CIP), and tetracycline(TC), under visible light illumination. The successful composited of g‐C3N4 with GSBC was demonstrated by various characterization results, in which the 5 : 1 mass loading ratio showed the best performance. g‐C3N4/GSBC possessed a larger specific surface area (71.09 m2/g), suitable band gap (2.66 eV), more catalytically active species, and higher utilization efficiency of visible light than powdered g‐C3N4. The removal efficiency of the new composite was higher than that of g‐C3N4 for the three antibiotics, with removal efficiencies of 87.2 %, 83.2 %, and 72.2 % for SMZ, TC, and CIP, respectively. The analysis of its photodegradation mechanism revealed that h+ and ⋅O2− are responsible for the antibiotics′ decomposition. According to the HPLC‐MS results, the possible photocatalytic mechanism and reaction pathways have been proposed. This work provided a new way for the synthesis of molding photocatalysts as an efficient photocatalyst for the degradation of organic contaminants. [ABSTRACT FROM AUTHOR]

Published
2023
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56. Enhanced photocatalytic performance of Bi4O5Br2 with three-dimensionally ordered macroporous structure for phenol removal.

Author

Zhang, Kunfeng, Chen, Hongxia, Pei, Wenbo, Dai, Hongxing, Li, Junshan, and Zhu, Yongfa

Subjects
PHENOL, VALENCE bands, PHOTOCATALYSTS, CHARGE transfer, POLLUTANTS, SURFACE structure
Abstract

Herein, a series of three-dimensionally ordered macroporous (3DOM) Bi4O5Br2 photocatalysts with different macropore sizes were successfully fabricated via a polymethyl methacrylate (PMMA) template method. The photocatalytic activity for phenol degradation over 3DOM Bi4O5Br2 first increased and then decreased with the rise in macropore size. Specifically, 3DOM Bi4O5Br2-255 (macropore diameter ca. 170 nm) exhibits the best photocatalytic activity in the static system, which is about 4.5, 7.3, and 11.9 times higher than those of bulk Bi4O5Br2, Bi2WO6, and g-C3N4, respectively. Meanwhile, high phenol conversion (75%) is also obtained over 3DOM Bi4O5Br2-255 in the flow system under full spectrum irradiation. Furthermore, 3DOM Bi4O5Br2-255 also shows strong mineralization capacity owing to the downward shift of valance band position (0.15 V) as compared with Bi4O5Br2. Total organic carbon (TOC) removal rate over 3DOM Bi4O5Br2-255 (62%) is much higher than that of Bi4O5Br2 (17%). The enhancement in photocatalytic performance of 3DOM Bi4O5Br2-255 is attributable to its better phenol adsorption, O2 activation, and charge separation and transfer abilities. This work combines the advantages of 3D structure and surface dangling bonds, providing new possibilities for designing highly efficient photocatalysts for pollutants removal. [ABSTRACT FROM AUTHOR]

Published
2023
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66. In situ formation of DNA-templated copper nanoparticles as fluorescent indicator for hydroxylamine detection

Author

Yu Wenhe, Zhang Kunfeng, Song Quanwei, Xianyuan Du, Changzhao Chen, Lixia Yang, Hongkun Chen, and Zheng Jin

Subjects
In situ, Detection limit, Chemistry, Reducing agent, General Chemical Engineering, Nanoparticle, chemistry.chemical_element, 02 engineering and technology, General Chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Fluorescence, Combinatorial chemistry, Copper, 0104 chemical sciences, chemistry.chemical_compound, Hydroxylamine, Molecule, 0210 nano-technology
Abstract

Herein, we develop a facile method for selective and sensitive detection of hydroxylamine (HA) based on the in situ formation of DNA templated copper nanoparticles (DNA-CuNPs) as fluorescent probes. It is firstly found that HA as a reducing agent can play a key role in the in situ formation of fluorescent DNA-CuNPs. This special optical property of DNA-CuNPs with (λex = 340 nm, λem = 588 nm) with a mega-Stokes shifting (248 nm) makes it applicable for the turn-on detection of HA. In addition, this fluorescent method has several advantages such as being simple, rapid, and environmentally friendly, because it avoids the traditional organic dye molecules and complex procedures. Under optimized conditions, this platform achieves a fluorescent response for HA with a detection limit of 0.022 mM. Especially, successful detection capability in tap waters and ground waters exhibits its potential to be general method.

Published
2019

71. Toluene Oxidation over the M–Al (M = Ce, La, Co, Ce–La, and Ce–Co) Catalysts Derived from the Modified “One-Pot” Evaporation-Induced Self-Assembly Method: Effects of Microwave or Ultrasound Irradiation and Noble-Metal Loading on Catalytic Activity and Stability

Author

Rastegarpanah, Ali, primary, Meshkani, Fereshteh, additional, Liu, Yuxi, additional, Deng, Jiguang, additional, Jing, Lin, additional, Pei, Wenbo, additional, Zhang, Kunfeng, additional, Hou, Zhiquan, additional, Han, Zhuo, additional, Rezaei, Mehran, additional, and Dai, Hongxing, additional

Published
2020
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86. Application of an improved harmonic detection algorithm in harmonic control of charging station

Author

Zhang Kunfeng

Subjects
Charging station, History, Harmonic control, Computer science, business.industry, Harmonic, Electrical engineering, business, Computer Science Applications, Education
Abstract

With the rapid prosperity of the electric vehicle industry, the demand for charging stations providing charging services has become increasingly strong, which followed by serious power quality problems. Because the current level of the charging station changes gradually with time, the harmonic current generated by the charging station will also change gradually with time. The influence of the low-pass filter leads to the slow start-up and tracking speed of harmonic current detection method based on ip-iq algorithm, which cannot meet the need of harmonic control in charging station. In this paper, the harmonic characteristics and basic structure of six-pulse rectifier charging pile are analyzed in detail, and the charging station model based on six-pulse rectifier charging pile is established. At the same time, in order to meet the need of harmonic suppression, a harmonic current detection algorithm based on variable step size LMS/LMF algorithm is proposed and analyzed comprehensively. The simulation and experimental results show that compared with the traditional harmonic detection algorithm, the improved harmonic detection algorithm has obvious advantages in many aspects, such as start-up and tracking speed, and has good engineering application prospects.

Published
2019

88. Ru Nanoparticles Supported on Oxygen‐Deficient 3DOM BiVO4: High‐Performance Catalysts for the Visible‐Light‐Driven Selective Oxidation of Benzyl Alcohol.

Author

Zhang, Kunfeng, Liu, Yuxi, Deng, Jiguang, Jing, Lin, Pei, Wenbo, Han, Zhuo, Zhang, Xing, and Dai, Hongxing

Subjects
*BENZYL alcohol, *BENZALDEHYDE, *ALCOHOL oxidation, *SELECTIVE catalytic oxidation, *ETHYLENE glycol, *CATALYSTS, *CATALYTIC activity, *NANOPARTICLES
Abstract

Developing novel photocatalysts for green synthesis of important organic intermediates under mild conditions is of great significance in industry. In this work, we synthesized the oxygen‐deficient three‐dimensionally ordered macroporous (3DOM) BiVO4‐supported nanosized Ru (xRu/3DOM BiVO4, x=0.24–2.16 wt %) catalysts by the polymethyl methacrylate‐templating, ethylene glycol reduction, and post‐thermal treatment methods. Physicochemical properties of the materials were characterized using the various techniques, and their catalytic activities for the visible‐light‐driven selective oxidation of benzyl alcohol to benzaldehyde were measured. It is found that the Ru nanoparticles (NPs) with a size of 1.2–1.5 nm were uniformly dispersed on the surface of 3DOM BiVO4, which gave rise to a significant enhancement in photocatalytic activity. Benzyl alcohol conversion first went up and then dropped down with the rise in loading of Ru NPs. The 0.95Ru/3DOM BiVO4−Ar‐300 sample was thermally treated in an Ar flow at 300 °C for 4 h showed the highest benzyl alcohol conversion (78 %) with a benzaldehyde selectivity of 100 % (benzaldehyde formation rate was 1380 μmol/(g h) after 6 h of illumination) and good photocatalytic stability. The high dispersion of Ru NPs and formation of oxygen vacancies in 3DOM BiVO4 improved separation and transfer efficiency of the photogenerated electrons/holes and increased the superoxide radical concentration. In addition, the possible mechanism of benzyl alcohol oxidation over 0.95Ru/3DOM BiVO4−Ar‐300 was also discussed. The oxygen‐deficient 3DOM BiVO4‐supported Ru NPs have promising applications for selective oxidation of organics. [ABSTRACT FROM AUTHOR]

Published
2019
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95. Pd/meso-CoO derived from in situ reduction of the one-step synthesized Pd/meso-Co3O4: high-performance catalysts for benzene combustion.

Author

Zhao, Xingtian, Zhang, Ran, Liu, Yuxi, Deng, Jiguang, Xu, Peng, Lv, Sijie, Li, Shuang, Pei, Wenbo, Zhang, Kunfeng, and Dai, Hongxing

Subjects
PALLADIUM catalysts, SELF-propagating high-temperature synthesis, COMBUSTION
Abstract

The chemical state of Pd plays an important role in the catalytic combustion of volatile organic compounds (VOCs). In this work, we adopted a novel one-step modified KIT-6-templating strategy with nitrates of cobalt and palladium as the metal source to successfully synthesize the three-dimensionally ordered mesoporous Co3O4-supported Pd nanoparticles (0.85 wt% Pd/meso-Co3O4, denoted as 0.85Pd/meso-Co3O4). The 0.93 wt% Pd/meso-CoO (denoted as 0.93Pd/meso-CoO) and 1.08 wt% Pd/meso-Co–CoO (denoted as 1.08Pd/meso-Co–CoO) samples were prepared via in situ reduction of 0.85Pd/meso-Co3O4 in a H2 flow at 200 and 350 °C, respectively. Among these samples, 0.93Pd/meso-CoO exhibited the highest catalytic activity for benzene combustion (T50% = 167 °C and T90% = 189 °C at a space velocity of 40 000 mL (g h)−1). The chemical state of Pd on the 0.93Pd/meso-CoO surface was metallic Pd0, which favored oxygen activation to active adsorbed oxygen (Oads) species, hence rendering this sample to possess the largest desorption of Oads species below 400 °C. The intermediates of formate, acetate, maleate, and phenolate were generated via the interaction of benzene and Oads species. We conclude that the excellent catalytic performance of 0.93Pd/meso-CoO was related to the mainly formed Pd0 species, good oxygen activation ability, and high surface area. [ABSTRACT FROM AUTHOR]

Published
2019
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98. Coupled Palladium–Tungsten Bimetallic Nanosheets/TiO2Hybrids with Enhanced Catalytic Activity and Stability for the Oxidative Removal of Benzene

Author

Liang, Yijing, Liu, Yuxi, Deng, Jiguang, Zhang, Kunfeng, Hou, Zhiquan, Zhao, Xingtian, Zhang, Xing, Zhang, Kaiyue, Wei, Rujian, and Dai, Hongxing

Abstract

Since the conventional Pd-based catalysts often suffer severe deactivation by water, development of a catalyst with good activity and moisture-resistance ability is of importance in effectively controlling emissions of volatile organic compounds (VOCs). Herein, we report the efficient synthesis of ultrathin palladium–tungsten bimetallic nanosheets with exceptionally high dispersion of tungsten species. The supported catalyst (TiO2/PdW) shows good performance for benzene oxidation, and 90% conversion is achieved at a temperature of 200 °C and a space velocity of 40 000 mL g–1h–1. The TiO2/PdW catalyst also exhibits better water-tolerant ability than the traditional Pd/TiO2catalyst. The high catalytic efficiency can be explained by the facile redox cycle of the active Pd2+/Pd0couple in the close-contact PdOx–WOx–TiO2arrangement. We propose that the reason for good tolerance to water is that the lattice oxygen of the TiO2/PdW catalyst can effectively replenish the oxygen in active PdOxsites consumed by benzene oxidation. A four-step benzene transformation mechanism promoted by the catalyst is proposed. The present work provides a useful idea for the rational design of efficient bimetallic catalysts for the removal of VOCs under the high humidity conditions.

Published
2019
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