Gaseous Detonation Method Research Articles

Characterization and Mechanism Elucidation of Nano-TiO2 Composites Prepared by Gaseous Detonation Method.

In this study, a series of nano-TiO2 composite materials, including nano-TiO2, nano-SnO2/TiO2, nano-SiO2/TiO2, and nano-Fe2O3/TiO2, were successfully synthesized via the gaseous detonation method. Comprehensive characterization of the synthesized samples was carried out through X-ray diffraction (XRD), transmission electron microscopy/high-resolution TEM (TEM/HRTEM), scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS), Brunauer-Emmett-Teller (BET) method, and Fourier transform infrared (FTIR) analysis, which unveiled the significant influence of precursor types on the microstructure of the composite materials. Specifically, the incorporation of Sn4+ promoted the transformation of TiO2 to the rutile phase, reducing particle sizes from 25 to 19 nm and increasing the specific surface area from 44 to 86 m2/g. In contrast, the introduction of SiO2 impeded the rutile phase formation, leading to a marked reduction in particle size to 14 nm and an enhancement of the specific surface area to 104 m2/g. Furthermore, the presence of Fe3+ promoted the formation of the rutile phase and enabled particle growth to 44 nm. These findings not only deepen the understanding of structural control in the synthesis of nano-TiO2 composite materials via the gaseous detonation method but also highlight the critical role of precursor selection in determining the properties of the resulting materials.

Correction to: One-pot rapid preparation of carbon-coated Co–Cu alloy composites via the gaseous detonation method

Correction to: One-pot rapid preparation of carbon-coated Co–Cu alloy composites via the gaseous detonation method

Wave Absorption Properties of Co–C Nanoparticles Prepared by the Gaseous Detonation Method

Wave Absorption Properties of Co–C Nanoparticles Prepared by the Gaseous Detonation Method

Wave Absorption Properties of Co-C Nanoparticles Prepared by the Gaseous Detonation Method

Wave Absorption Properties of Co-C Nanoparticles Prepared by the Gaseous Detonation Method

One-pot millisecond preparation of carbon-coated SiO2 nanoparticles

Carbon-coated SiO2 nanoparticles (SiO2@C NPs) as a promising anode for lithium-ion batteries have been reported to further improve lithium-storage performance and possess more outstanding electrochemical performance. However, it is still a challenge to fabricate SiO2@C NPs using a facile, rapid and efficient strategy. In this work, SiO2@C NPs on a gram scale are produced by a facile and one-pot gaseous detonation method in 3–5 ms without any post-treatment using benzoic acid (BA) and silicon tetrachloride (ST) as the carbon and silicon sources respectively as well as hydrogen and oxygen as explosion sources. The results indicate that the molar ratio of BA and ST plays a crucial role in the formation of SiO2@C NPs. The as-prepared SiO2@C NPs with an average size of 83.5 nm are quasi-spherical and possess obvious core-shell structure. Additionally, on the basis of our experimental results and the characteristics of gaseous detonation, we speculate the formation mechanism of SiO2@C NPs.

One-pot millisecond preparation of quench-resistant solid-state fluorescence carbon dots toward an efficient lubrication additive

Currently, the investigation on preparation, photoluminescence (PL) mechanism and application of solid state fluorescent CDs (SSFCDs) is still in the preliminary stage. It is particularly urgent to research on this issue. Herein, a one-pot gaseous detonation method is employed to directly synthesize SSFCDs within milliseconds using citric acid (CA) and urea as precursors for the first time. The SSFCDs exhibit dependent emission with the excitation/emission maximum of 370/452 nm. On the basis of studying the structural and optical characteristics of the SSFCDs and thermal annealing SSFCDs (A-CDs) as well as the properties of gaseous detonation, we speculate the PL mechanism and formation mechanism of SSFCDs. More importantly, the prepared SSFCDs without any purification as additives for poly(ethylene glycol) (PEG) obtain a super-low mean friction coefficient of 0.024 and wear scar diameter of 0.57 mm under 600 N at optimal concentration of 0.5 wt%, reducing by 60.7% and 19.7% respectively in comparison with that of pure PEG. The SSFCDs-based additives reported here display excellent friction-reducing and antiwear performance for PEG.

Gaseous detonation synthesis of Co@C nanoparticles/CNTs materials

Co@C/CNTs magnetic carbon nanomaterials were fabricated by a gaseous detonation method with cobalt (III) acetylacetonate (Co(acac)3) as precursor and a mixture gas of hydrogen and oxygen as explosion source. The current work investigates how proportion of oxygen in the mixture gas affects the morphologies, phases, and degree of graphitization of Co@C/CNTs nanomaterials. The characterization of transmission electron microscopy indicates that the samples were consisted of core-shell nanoparticles and nanotubes, and the proportion of oxygen had little influence on the morphologies of the samples. X-ray diffraction and Raman spectra analysis demonstrate that the core-shell particles and nanotubes were Co@C and CNTs, respectively. The cobalt nanoparticles generated from the decomposition of Co(acac)3 would be oxidized to CoO when the proportion of oxygen was greater than 50% in the mixture gas. Though the degree of graphitization of Co@C/CNTs nanomaterials was little affected by the proportion of oxygen, the particle size of Co@C increased with the increase of the proportion of oxygen in the mixture gas, simultaneously, the carbon matrix was decreased.

Graphene quantum dots prepared by gaseous detonation toward excellent friction-reducing and antiwear additives

A great deal of research has been focused on the photoluminescence (PL) behaviors of graphene quantum dots (GQDs), but tribological characteristics against GQDs still remain an open issue. Herein, four kinds of powdery GQDs are successfully synthesized via a one-pot gaseous detonation method without any post-treatment or purification. The tribological properties of GQDs serving as lubricant additives for 150SN mineral oil are investigated in detail using a four-ball tester by altering the concentration and types of GQDs. The results demonstrate that GQDs can act as excellent performance additives. In particular, the mean friction coefficient, wear scar diameter and depth of lower balls lubricated by 150SN mineral oil under 392 N correspondingly reduce by 65.2%, 43.5% and 90.9%, when appropriate types of GQDs at optimal additive concentration of 0.8 wt% are introduced. Finally, on the basis of microstructures, compositions and tribological properties of four kinds of GQDs, a reasonable lubricating mechanism of GQDs-based additives is proposed and illustrated that excellent friction-reducing and antiwear properties may be attributed to the synergetic effects, including polishing effect and mending effect.

A solvent-free gaseous detonation approach for converting benzoic acid into graphene quantum dots within milliseconds

Graphene quantum dots (GQDs) in high reproducibility are synthesized by a gaseous detonation method which converts untreated benzoic acid (BA) precursor into powdered GODs without complicated post-treatment in 3–5 ms. The as-prepared GQDs resulting in an absolute photoluminescence quantum yield (PLQY) of 21.5% exhibit dual-wavelength-independent emission with the maximum PL emission at 431 nm and 460 nm under excitation maximum at 300 nm dispersed in ethyl alcohol. Based on surface structure, photoluminescence (PL) behaviors of GQDs and the characteristics of gaseous detonation, the formation mechanism of GQDs is speculated. Moreover, further study regarding the optical properties of reducing GQDs (R-GQDs) and thermal annealing GQDs (A-GQDs), it is possible to reveal PL mechanism of GQDs. This research not only provides a one-pot solvent-free route to rapid and large-scale preparation of GQDs, but also accounts for the hypothetic formation and PL mechanism of the obtained GQDs.

Growth mechanism and wave-absorption properties of multiwalled carbon nanotubes fabricated using a gaseous detonation method

Multiwalled carbon nanotubes (MWCNTs) were fabricated via the detonation of a mixed gas consisting of ferrocene vapor, methane, and oxygen. The samples were characterized using transmission electron microscopy, X-ray diffraction, Raman spectroscopy, vibrating sample magnetometry, and a vector network analyzer. The results indicate that the samples were MWCNTs that were about 30 nm in external diameter, about 15 nm in inner diameter. The ferrocene dosage had an obvious effect on the morphology, degree of graphitization, and magnetic property of the MWCNTs. The growth mechanism of the MWCNTs in the gaseous detonation process was discussed using the detonation Zeldovich-von Neumann-Döring model and a vapor-liquid-solid growth model. The minimum reflection loss of the MWCNTs was −6.1 dB at 11.2 GHz with a thickness of 2 mm, which is lower than that of the MWCNTs prepared via other methods, and the reasons for this result are analyzed in the paper.

Characterization and photocatalytic properties of SiO 2 –TiO 2 nanocomposites prepared through gaseous detonation method

Characterization and photocatalytic properties of SiO 2 –TiO 2 nanocomposites prepared through gaseous detonation method

Characterization and photocatalytic properties of nano-Fe2O3–TiO2 composites prepared through the gaseous detonation method

Abstract Nano-Fe 2 O 3 –TiO 2 composite was prepared through the gaseous detonation method. The effects of Fe 3+ contents on the morphology, properties, and photocatalysis of nano-Fe 2 O 3 –TiO 2 composite were also studied. Sample structures, components, particle size, morphology, and optical properties were characterized by X-ray diffraction, transmission electron microscopy, energy dispersive spectroscopy, UV–vis spectroscopy, and Fourier transform infrared spectroscopy. Photocatalytic activity was tested through a UV-based methyl orange solution degradation experiment. Results demonstrated that high Fe 3+ content can promote the conversion of TiO 2 from the anatase phase to the rutile phase, reduce the energy gap of samples, increase the photoresponse range, form Fe 2 O 3 –TiO 2 heterojunctions, and increase the photocatalytic activity of TiO 2 . When the Fe:Ti molar ratio of the precursor was 1%, the sample exhibited an anatase–rutile mixed crystal structure. The average particle size was approximately 20 nm, and the energy gap was 3.1 eV. The method achieved the highest photocatalysis at an apparent reaction rate constant of 0.142 min −1 .

Optimal Design and Preparation of Nano-TiO2 Photocatalyst Using Gaseous Detonation Method

Optimal Design and Preparation of Nano-TiO₂ Photocatalyst Using Gaseous Detonation Method

Characterization and photocatalytic properties of SnO2–TiO2 nanocomposites prepared through gaseous detonation method

SnO2-TiO2 nanocomposites were prepared by gaseous detonation method. The effects of SnO2 content on morphology, properties and photocatalytic properties of SnO2-TiO2 nanocomposites were explored. Structure, components, grain size, morphology and optical properties of samples were characterized by X-ray diffractometer (XRD), Transmission electron microscope (TEM), Energy Dispersive Spectrometer (EDS), UV–vis spectroscopy, and Infrared spectroscopy (FIIR). Photocatalytic properties were measured by methyl orange solution removal experiments under UV irradiation at an initial concentration of 10mg/L. Results demonstrated that SnO2 content is negatively related to the grain size of samples. The TiO2 content in the rutile phase is positively correlated with the photocatalytic properties of samples. The samples were anatase-rutile mixed crystal when the molar ratio of Sn:Ti is 1:4. The grain size of mixed crystal in anatase-rutile phase ranged between 8nm and 40nm and the energy gap was 3.03eV. This phase demonstrated the highest photocatalytic properties. The methyl orange solution was degraded completely at 25min at a constant reaction rate of 0.146min−1. The rate of photocatalytic reaction was 46% higher than that of the prepared TiO2 and about 13% higher than that of P25.

Influence of TiCl4 concentration on the photocatalytic performance of nano-TiO2 synthesized by gaseous detonation

TiO2 photocatalyst is prepared via the gaseous detonation method. The structure and properties of the samples are investigated by using x-ray diffractometer, transmission electron microscope, UV–vis spectroscopy, and Infrared spectroscopy, and the photocatalytic performance of the products is measured by methyl orange solution removal experiments under UV irradiation. Results indicate that the initial concentration of TiCl4 exerts a significant impact on the particle size of the resultant samples. The average particle size of the samples decreases significantly as the TiCl4 concentration decreases. When the TiCl4 initial concentration is 2.09 mol m−3, the prepared sample shows the highest photocatalytic activity, an average particle size of 18.8 nm, and anatase content of 87%. Furthermore, the band gap of the sample is 3.18 eV, and its rate constant k is 0.1 min−1. Photocatalytic activity of this sample is much higher than other products obtained in this work and slightly lower than commercial P25.

Influence Factors of Preparing Carbon-encapsulated Iron Nanoparticles by Gaseous Detonation Method

Effects of molar ratio of hydrogen to oxygen and ferrocene mass on synthesis of carbon-encapsulated iron nanoparticles (Fe@C) were studied. Fe@C were prepared by using ferrocene as material resource, which decomposed by high temperature and high speed caused by hydrogen and oxygen detonation in homemade detonation tube. The samples were characterized by X-ray diffraction, transmission electron microscope and high resolution transmission electron microscope and it can be found that the molar ratio of hydrogen to oxygen, and ferrocene mass interact each other in the preparation of Fe@C. The molar ratio of hydrogen to oxygen mainly influences the morphology, particle size and dispersion of Fe@C, while ferrocene mass has a great affect on the synthesis of Fe@C. Part of iron element will be oxidized at small dosage of ferrocene, on the contrary, ferrocene couldn’t be decomposed completely. When the molar ratio of hydrogen to oxygen is 2:1, ferrocene mass ranges in 2.5–3.5 g, spherical or ellipsoidal like Fe@C is prepared with a clear core-shell structure, and thickness of carbon shell at about 10 nm. In consideration of particle size uniformity, morphology structure and dispersion, the best condition for preparing Fe@C is, the molar ratio of hydrogen to oxygen at 2:1, ferrocene mass at 3.5 g. 第 5期 闫鸿浩, 等: 气相爆轰合成碳包铁的影响因素 543

Gaseous detonation synthesis and characterization of nano-oxide

Gaseous detonation is a new method of heating the precursor of nanomaterials into gas, and integrating it with combustible gas as mixture to be detonated for the synthesis of nanomaterials. In this paper, the mixed gas of oxygen and hydrogen is used as the source for detonation, to synthesize nano TiO2, nano SiO2 and nano SnO2 through gaseous detonation method, characterization and analysis of the products, it was found that the products from gaseous detonation method were of high purity, good dispersion, smaller particle size and even distribution. It also shows that for the synthesis of nano-oxides, gaseous detonation is universal.

Preparation and characterization of nanosized TiO 2 powders by gaseous detonation method

Nanosized TiO 2 powders were prepared for the first time by gaseous detonation method. The structure, composition and size distribution of the detonation product were systematically characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results indicate the powders are a mixed crystal of rutile and anatase exhibiting non-spherical grains, and the average size of particles was between 20 and 40 nm. The results of detonation pressure measurement show that the reaction took place under a deflagration-to-detonation transition (DDT) course.