RSC Advances
·
2016
·Vol. 6
·期 53
·47813-47819
·
IF 3.289
Yuyu Bu,Zhiwei Chen,Tian Xie,Weibing Li,Jin-Ping Ao
In this paper, we prepared a large-sized multilayer C3N4 ultrathin flake photocatalyst with an approximately 90% yield rate by a facile wet mechanical grinding method. The blue shift phenomenon of the UV-Vis diffuse reflectance spectrum and photoluminescence spectrum indicated that a quantum effect was formed with the thickness of g-C3N4 (g-CN) when decreased to ultrathin flakes. The photocatalysis water reduction for hydrogen evolution performance of ultrathin flake C3N4 (UF-CN) was approximate 3.2 times higher than that of g-CN. In addition, the photoelectrochemical (PEC) property of UF-CN was increased more dramatically than that of g-CN. There are two possible reasons for photocatalysis and PEC performances of UF-CN promotion. First, the valence band (VB) potential of UF-CN was 1.59 eV, which was 0.25 eV more positive than that of g-CN, thus the oxidation capacity of UF-CN photogenerated holes would be stronger than the bulk counterpart. Secondly, the electrons transfer capacity on the horizontal plane of UF-CN was increased with the layered structure of the g-CN exfoliated to an ultrathin structure, thus prolonging the life time of the photogenerated electrons.
研究领域:
材料科学
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光催化技术
·
纳米材料
✓ 已验证
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2019
·Vol. 43
·期 47
·18860-18867
·
IF 3.069
Xu Tang,Yang Yu,Changchang Ma,Guosheng Zhou,Xinlin Liu,Minshan Song,Ziyang Lu,Lei Liu
A novel biomass carbon quantum dots@Bi2WO6 (BC-QDs@Bi2WO6) photocatalyst with uniform dispersivity was prepared via a dialysis-assisted hydrothermal process. Multiple techniques including HR-TEM, XPS, UV-Vis, PL, photocurrent analysis, and electrochemical impedance spectroscopy were employed to investigate the morphology and structures as well as the optical and electronic properties of the as-prepared samples. The photocatalytic activity of BC-QDs@Bi2WO6 was assessed by the degradation of antibiotics (tetracycline, ciprofloxacin, and gatifloxacin). The improved photocatalytic activity was attributed to the quantum effect of BC-QDs, which acted as the light harvesting center, electron reservoir, and reaction center for degrading the pollutants. Furthermore, a plausible mechanism for photocatalysis was put forward according to the ESR and quenching experiments. The present work can have significant advantages in the construction of biomass carbon-based photocatalysts in pollutant degradation and improved light utilization.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
Catalysis Science & Technology
·
2022
·Vol. 12
·期 21
·6384-6397
·
IF 6.177
Zhi Zhu,Reeti Kumar,Liwen Luo,Sunita Varjani,Pengwei Huo,Jonathan Woon-Chung Wong,Jun Zhao
Photocatalytic degradation of pharmaceuticals in the aquatic environment is considered a promising strategy to address water pollution. In this study, a novel photocatalyst was constructed by decorating g-C3N4 (CN) with α-MoC1−x quantum dots (α-MoC1−x-QDs) through a facile calcination method. The catalyst showed enhanced tetracycline (TC) degradation performance under visible light. The unique Mo–N surface bonding states and quantum effect leading to superior TC degradation activity (89.1%) compared to pure CN (21.8%) were reported and revealed. More importantly, the mechanism for the significant enhancement of photocatalytic activity of the catalyst was investigated by DFT (density functional theory) calculations and photo-electrochemistry measurements. The results confirmed that the effect of α-MoC1−x-QDs on CN improved the light absorption capacity obviously, and the Mo–N surface bonding states accelerated the charge migration from CN to α-MoC1−x-QDs. Moreover, the TC degradation pathway, intermediates and photogenerated carrier transfer behaviors were also discussed in depth. This research provides a new strategy for the construction of noble-metal-free co-catalyst/semiconductor composite materials in the photocatalytic degradation of antibiotics.
研究领域:
环境科学
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材料科学
·
化学
✓ 已验证
DOI
高影响因子
CRYSTAL RESEARCH AND TECHNOLOGY
·
2017
·Vol. 52
·期 5
·1700009
·
IF 1
Tianxiang Xu,Yicheng Wang,Dazhi Lu,Zhongben Pan,Haohai Yu,Huaijin Zhang,Jiyang Wang
Barium calcium titanate (Ba 1-x Ca x TiO 3 , BCT), which can be used as a three-dimensional nonlinear photonic crystal, is an anomalous ferroelectric with tremendous electromechanical response. Its phase transition behavior depends closely on the Ca content. In particular, the rhombohedral-orthorhombic and orthorhombic-tetragonal transitions can disappear at two contents: x = 0.18 and 0.23, respectively, which is important to study a wide range of physical phenomena including the alluring quantum effects. In this work, based on the natural differences of the affinity of oxygen atoms on Ba and Ca atoms, we developed a growth atmosphere modulating mechanism to control the Ca content in BCT crystals aiming at achievement of the desired compositions (x = 0.18 and 0.23). With the same polycrystalline material (Ba 0.773 Ca 0.227 TiO 3 ), BCT single crystals with x = 0.189 and x = 0.225 were obtained under N 2 and air atmospheres, respectively. The structural and dielectric properties of the as-grown crystals were investigated and the differences were discussed. Besides, the influence of Ti 3+ imperfections on the diffused phase transition was studied, and the specific heats and transition enthalpies were also measured for characterizing the different phase transition properties.
研究领域:
材料科学
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物理学
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DOI
高影响因子
Nanoscale
·
2017
·Vol. 9
·期 6
·2376-2384
·
IF 7.367
Tao Yang,Wenna Liu,Lidong Li,Junhong Chen,Xinmei Hou,Kuo-Chih Chou
Aiming to achieve the synergistic enhancement of the surface-enhanced Raman scattering (SERS) and photoelectrocatalytic (PEC) performance on a noble metal–semiconductor, such as Au nanoparticles (NPs)–TiO2 nanotube arrays (TiO2 NTAs@hybrid Au NPs), theoretical calculation and experiments are performed. Theoretical calculation indicates that both the SERS and PEC performance can be enhanced by coupling different sized Au NPs on TiO2 NTAs based on synergizing the multiple plasmon resonance coupling and quantum effects. To further verify this mechanism, TiO2 NTAs@hybrid Au NPs are assembled via synthesis of TiO2 NTAs through the anodic oxidation process, followed by the deposition of different sized Au NPs onto the TiO2 surface simultaneously using physical vapor deposition (PVD) in this work. Such substrates exhibit excellent detection sensitivity towards organic dyes including Rhodamine B (RhB), the organic herbicide dichlorophenoxyacetic acid (2,4-D) and the organophosphate pesticide methyl-parathion (MP) with high reproducibility, stability and reusability. Meanwhile the PEC performance based on this substrate remains efficient compared with the reported results in the literature. The efficient PEC performance mainly originates from both the quantum effect of Au nanoparticles and the formation of a metal–semiconductor heterojunction. It is proposed that other noble metal–semiconductor complex nanomaterials can also obtain both enhanced SERS and PEC performance based on the above mechanism.
研究领域:
材料科学
·
化学
✓ 已验证
DOI
高影响因子
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