CRYSTENGCOMM
·
2019
·Vol. 21
·期 32
·4740-4746
·
IF 3.382
Jingbo He,Bo Sun,Yong Sun,Chengxin Wang
Although more than 250 polytypes of silicon carbide (SiC) crystals have been discovered, only very limited types of nanowires can be synthesized in a controllable manner. Both experimental and theoretical investigation reveal that 3C-SiC is the most stable form, which is the primary product of nanowires synthesized via various methods in thousands of reports. Although hexagonal phases, particularly the wurtzite structure with a bandgap of 3.33 eV is promising in optoelectronic applications, the fabrication of nanowires with theses phases is still rare. Herein, in this study, by precisely regulating the atmospheric conditions, we revealed that the CH4 supply resulted in the phase-selective growth between 3C- and 2H-SiC nanowires. As the CH4 flow rate increased, it was possible to fabricate 3C-SiC, hybrid 3C-/2H-SiC and 2H-SiC nanowires in a controllable manner. The possible mechanism is demonstrated accordingly. We believe this progress benefits the structural design and optoelectronic application of SiC nanowires.
研究领域:
材料科学
·
纳米技术
·
半导体物理
·
光电材料
·
晶体生长
✓ 已验证
DOI
高影响因子
CHEMISTRY OF MATERIALS
·
2013
·
IF 8.238
Shuijin Lei,Chunying Wang,Lei Liu,Donghai Guo,Chuanning Wang,Qingliu Tang,Baochang Cheng,Yanhe Xiao,Lang Zhou
Group I–III–VI ternary chalcogenides have attracted extensive attention as important functional semiconductors. Among them, Cu–In–S compounds have seen strong research interest due to their potential applications in high-efficiency solar cells. However, the controllable synthesis of Cu–In–S nanostructures with different phases is always difficult. In this research, zinc-blende CuInS2, wurtzite CuInS2, and spinel CuIn5S8 could be selectively synthesized using spinel In3–xS4 as the precursor by a simple solvothermal method. X-ray powder diffraction was used to determine the phase and crystal structure, and transmission electron microscopy was employed to characterize the morphologies of the as-prepared samples. Experiments showed that the acidity–basicity of the reaction system and the coordination and reducibility of the capping ligands were crucial to the final phases of the products. The UV–vis–NIR spectra of the three phases all exhibited a broad-band absorption over the entire visible light and extending into the near-infrared region, and the zinc-blende, wurtzite, and spinel Cu–In–S nanocrystals showed band gaps of 1.55, 1.54, and 1.51 eV, respectively, which indicates their potential applications in thin-film solar cells.
研究领域:
材料科学
·
半导体物理
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
CRYSTENGCOMM
·
2017
·Vol. 19
·期 45
·6736-6743
·
IF 3.474
Chunwei Dong,Rui Ge,Dong Yao,Zhennan Wu,Zidong Wang,Yi Liu,Bai Yang,Hao Zhang
Although significant progress has been achieved in the synthesis of hollow nanoparticles (NPs), research on copper-based multinary chalcogenide (CMC) semiconductor NPs with hollow structures is still less developed. In this work, we demonstrate an effective method for the phase-selective synthesis of cubic Cu2GeS3 hollow NPs (HNPs) with huge cavities and thin shells. This method includes the nucleation of Cu2−xS seeds, followed by unequal diffusion between Cu+ and Ge4+. A common rule for the phase-selective growth of CMC NPs has been revealed: the nucleation step is the crystal phase-determining step in the growth process of CMC NPs, and the sulfur sources govern the crystal phase of the nucleus. Because of their huge cavities, the as-prepared large Cu2GeS3 HNPs are proved to be macroporous materials with a specific surface area of 22.1 m2 g−1. Besides, cubic Cu2GeS3 HNPs with small cavities are also synthesized, following the same method with little modification. By integrating the advantages of the large Cu2GeS3 HNPs (high surface-to-volume area) and the small Cu2GeS3 HNPs (good dispersibility and monodispersity), a new kind of two-layer photoelectrode is prepared. Compared with the photoelectrodes prepared using pure large and small Cu2GeS3 HNPs, the two-layer photoelectrode exhibits superior performance for photoelectrochemistry due to the high interface area of the upper layer and the ideal compactness of the bottom layer.
研究领域:
纳米材料科学
·
半导体材料
·
光电子化学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2017
·Vol. 7
·期 86
·54861-54865
·
IF 3.108
Kun Liu,Houkun Long,Guangyi Wang,Yongbin Sun,Chao Hou,Jian Dong,Xiaoqun Cao
The catalyst Cu3Pt1–Cu2O/SiC was facilely prepared via the in situ reaction of the corresponding compounds supported on SiC in the reaction stream. Cu3Pt1–Cu2O/SiC exhibits excellent catalytic activity for the oxidation of alcohols (conversion of benzyl alcohol and selectivity of benzyl aldehyde are 93% and 98% respectively). The reduction of active Cu2O to inactive Cu0 is the cause behind the deactivation of Cu/SiC. For Cu3Pt1–Cu2O-7/SiC, a Cu2O–Cu3Pt1 alloy formed under the reaction conditions plays an important role in the reaction. Active 5 nm Cu2O nanoparticles are stabilized by the inactive Cu3Pt1 alloy, which was confirmed by control experiments, characterization results and a three-step experiment.
研究领域:
催化化学
·
材料科学
·
表面化学
✓ 已验证
产品关联
DOI
高影响因子
Reaction Kinetics Mechanisms and Catalysis
·
2015
·Vol. 116
·期 2
·451-466
·
IF 1.17
Jiang Dahao,Mao Jun,Fang Zheng,Ni Jun,Zhang Qunfeng,Li Xiaonian
In this paper, the deactivation causes of the Pd/SiO 2 catalyst for continuous liquid-phase selective hydrogenation of 6,10,14-trimethylpentadeca-13-en-2-one in 2000 h of pilot plant test were systematically investigated by N 2 adsorption–desorption, thermogravimetric and differential thermal analyses, scanning electron microscope, transmission electron microscope, X-ray diffraction, X-ray fluorescence, experiments of CO poisoning and regeneration, and laboratory retests of the deactivated catalyst samples. The pore textures of Pd/SiO 2 catalysts were not destructed during the pilot test, while there were no obvious carbonaceous deposits appearing on the deactivated catalyst samples. The sintering and crystallization of Pd metal nanoparticles were found, which could be partially accountable for the deactivation of Pd/SiO 2 catalysts. Though Pd leaching did not take place in the pilot test, the Pd active phase could be slightly poisoned by sulfur impurities from feedstock hydrogen. Combining the results of CO poisoning and regeneration experiments with those of compositional analyses of fresh and circulating hydrogen in the pilot test, it could be concluded that CO poisoning should be another important reason for the deactivation of the Pd/SiO 2 catalyst due to high concentration of CO in the reaction system of pilot test and relatively low reaction temperature in the middle and at the bottom of the catalyst bed. Fortunately, the CO poisoned Pd/SiO 2 catalyst in the pilot test could be in situ regenerated by installing a purifier for CO elimination from the circulating hydrogen and increasing the temperature of the whole catalyst bed to slightly higher than 383 K.
研究领域:
催化化学
·
材料科学
·
工业化学
✓ 已验证
产品关联
DOI
高影响因子
SCRIPTA MATERIALIA
·
2025
·
IF 5.6
Yilong Yang,Xuan Ge,Jianguo Li,Qiaodan Hu
Extreme solidification processes in advanced manufacturing (e.g., laser additive manufacturing and in space fabrication) amplify challenges in predicting phase selection under severe thermodynamic non-equilibrium. Using aerodynamic levitation containerless processing, we investigate the solidification behavior of pseudo-binary MgTiO 3 -TiO 2 system. Our experiments reveal an anomalous trans-phase-regime selection phenomenon in which the thermodynamically stable MgTi 2 O 5 phase is kinetically suppressed from precipitation. This selection arises from nucleation kinetic barriers of MgTi 2 O 5 , where coupled undercooling and compositional fluctuations destabilize critical nuclei formation. By integrating composition- and temperature-dependent interfacial energy dynamics into classical nucleation theory , we develop a predictive framework that quantitatively maps anomalous phase selection regions. This approach establishes the first non-equilibrium kinetic phase diagram of this system with experimental validation, resolving long-standing discrepancies between equilibrium predictions and non-equilibrium experimental outcomes. The proposed methodology establishes a generalized paradigm for phase selection prediction, offering transformative insights into microstructure and phase control under extreme non-equilibrium solidification conditions.
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）