Ga2O3 Nanoparticles Research Articles

Synthesis and Characterisation of Palladium Doped Ga2O3 Nanoparticles as a Potent Microbiome Growth Inhibitor of Healthcare Waste

Synthesis and Characterisation of Palladium Doped Ga2O3 Nanoparticles as a Potent Microbiome Growth Inhibitor of Healthcare Waste

In Situ Synthesis of Liquid Metal Conductive Fibers toward Smart Cloth.

To meet the diverse needs of humans, smart cloth has become a potential research hotspot to replace traditional cloth. However, it is challenging to manufacture a flexible fabric with multiple functions. Here, we introduce a smart cloth based on liquid metal (LM) conductive fibers. Ga2O3 nanoparticles are obtained through ultrasonic pretreatment. Furthermore, a coordination bond is formed between thiol groups on the surface of protein fibers and Ga2O3 through a scraping method, allowing Ga2O3 particles to be grafted onto the surface of protein fibers in situ. Finally, LM conductive fibers are encapsulated using a photocuring adhesive. In addition, a wearable smart cloth integrated with multiple sensors has been developed based on LM conductive fibers. Users can not only monitor their movement trajectory and the surrounding environment in real time but also have their data supervised by family members through a client, achieving remote and continuous monitoring. The development of this wearable smart cloth provides strong support for future wearable, flexible electronic devices.

[formula omitted] mediated green synthesis of Ga2O3-ZnO nanocomposite for display technology and latent finger print detection

For the first time, Ga2O3-ZnO (GaZn) Nanocomposites (NCs) were synthesized by Green’s method using Aeglemarmelos fruit extract as a reducing agent via solution combustion method. Bragg’s reflection clearly confirms the formation of monoclinic and hexagonal Wurtzite structure of Ga2O3 and ZnO nanoparticles respectively. The crystallite size calculated by Scherrer’s method was found to be 21 nm. The agglomerated, irregular shape and sized NCs are observed in surface morphology. The direct band gap energy was calculated using Wood and Tauc’s plot which was found to be 3.1 eV. Photoluminescence emission spectra of GaZn NCs recorded at 350 nm consist of broad emission spectra with different sharp emission peaks overlapped over the broad spectra. CIE and CCT coordinates confirm the intense blue emission of synthesized NCs. Further, the synthesized NCs are analyzed for latent fingerprint (LPF) in the field of forensic application.

Controllable synthesis of gallium-containing MFI zeolite for bifunctionally catalyzing methanol aromatization

Ga-MFI zeolites with controllable crystal sizes were hydrothermally synthesized by using colloidal silicalite-1 as seed crystals and their catalytic performances for methanol-to-aromatics (MTA) were evaluated. It was found that the crystal size of as-made Ga-MFI zeolite became small with the adding amounts of seed crystals. Small-sized Ga-MFI zeolite with short channels shows much better coking-resistance and thus longer catalytic lifetime owning to its more favorable outward diffusion of aromatic products. In addition, the stability could be further improved by impregnating gallium species into Ga-MFI zeolite, but which slightly sacrificed its aromatic selectivity. The Ga species with different locations in zeolite play distinct roles in MTA. The weak intrinsic protonic acidity from tetrahedral framework Ga3+ could suppress hydrogen transfer reactions for light alkane formation while non-framework gallium species especially Ga2O3 nanoparticles promoted the dehydrocyclization process. The synergy between the strong Brønsted and weak Lewis acid sites contributes to the excellent aromatic yield.

PHOTOLUMINESCENCE PROPERTIES OF Nd3+, Yb3+ CODOPED Ga2O3 NANOPARTICLES

The availability of sensitive photon detectors and inexpensive lasers allowed us to explore more efficient fluorescent probes that will work in the second near-infrared optical window. In this study, the optical properties of Nd3+ and Yb3+ co-doped Ga2O3 nanoparticles were studied. In order to indicate the correlation between particle size, crystallinity, and optical property of present samples XRD, TEM, and Photoluminescence analyses were performed. Various excitation wavelengths and dopant concentrations were used to understand the energy transfer mechanism in Nd3+ and Yb3+ co-doped Ga2O3 nanoparticles. As the excitation wavelength increased from 325 nm to 477 and 515 nm, Yb3+ emission peak intensity decreased while Nd3+ emission peak intensity increased. This inverse relationship between the emission intensities of Yb3+ and Nd3+ ion showed the presence of energy transfer between them. The resulting emission peaks were broad and weak, indicating the presence of a non-radiative decay channel due to the crystal defects.

Hydrothermal preparation of oxide (Ga2O3, ZnO, TiO2) and derivative nanoparticles

A brief review of our recent research on preparation and characterization of oxide nanoparticles and their derivatives by hydrothermal growth is presented. A series of Ga2O3 , ZnO, and TiO2 nanoparticles, as well derivative nanomaterials including GaN nanowires and ZnO/TiO2 nanocompostes have been prepared. Ga2O3 and ZnO nanopowders have been produced using metal nitrate hydrates as precursors, while Titanium isopropoxide was used for preparation of TiO2 nanopowders. GaN nanowires have been produced by nitridation of Ga2O3 nanomaterials. The produced nanomaterials have been characterized scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis and Fourier transform infrared (FTIR) spectroscopy. Ga2O3 nanoparticles doped with Eu3+ ions have been characterized by photoluminescence spectroscopy in order to assess their prospects in developing nanophosphors materials.

Pomegranate-like gallium oxide nanospheres coated with nitrogen-doped carbon as an anode for lithium-ion batteries with an ultra-long cycle life

Ga-based materials have emerged as novel self-healing anodes that can spontaneously repair cracks during cycling. However, Ga-based alloying is limited by an unstable solid–electrolyte interphase (SEI) and severe aggregation resulting from the fluidity of Ga. In this study, Ga2O3 nanoparticles of ∼20 nm were synthesized. By confining and separating the Ga2O3 nanoparticles using doped carbon shells, Ga2O3@C with a pomegranate-like structure was successfully fabricated and used as an anode for ultra-long-life lithium-ion batteries. The carbon shell prevents aggregation of the lithium storage reaction product (Ga), provides better electrical conductivity, and forms a more stable SEI. The obtained Ga2O3@C anode exhibits a mixed lithium storage mechanism consisting of both diffusion-controlled and capacitive-controlled processes, with a pseudocapacitive contribution of up to 75.0 % at 1.0 mV s−1. The accelerated electrochemical reaction kinetics and high pseudocapacitive contribution of Ga2O3@C help deliver excellent cycling stability and rate properties. The Ga2O3@C anode can retain a capacity of ∼297.4 mAh g−1 within 3000 cycles at a high current density of 2 A g−1.

Partial Disproportionation Gallium-Oxygen Reaction Boosts Lithium-Oxygen Batteries

Ex-situ catalysts have been used for Li-oxygen batteries (LOBs), mostly resulting in polycrystalline Li2O2 as the discharge product, whose high energy barrier for oxygen evolution impedes the extraction of full potential of LOBs. In this study, a partial disproportionation gallium-oxygen reaction of superoxide in (Ga2O2)2+2(O2−) is subtly created prior to the lithium-oxygen one, in-situ growing Ga2O3 nanoparticles at cathode. The Ga2O3 induce the formation of poorly crystalline Li2O2, opposite to the conventional polycrystalline one. Benefitting from the crystallinity and morphology transformations of Li2O2, the chemical oxidation reaction kinetics between iodide redox mediators (RMs) and Li2O2 is significantly enhanced. In this regard, some issues related to RMs, for instance, the well-known Li-I2 side reactions and shuttle effect between the residual I3− and Li anode, can be predominantly suppressed. As a result, the cyclability of the LOBs are significantly improved with stable electrical energy efficiency. Our results lead to two conclusions: (1) non-lithium metal-oxygen reaction with higher thermodynamic potential than lithium-oxygen one is corroborated by theoretical calculations, which can in-situ produce nano-sized metal oxides particles at cathode, functioning surface growth of poorly crystalline Li2O2, and (2) acceleration of the reaction kinetics between the Li2O2 and the oxidized state of RMs is experimentally confirmed, which creates a new solid-soluble mixed catalytic mechanism.

Lenticular Ga-oxide nanostructures in thin amorphous germanosilicate layers - Size control and dimensional constraints

Gallium incorporation in silicate glasses gives rise to compounds in which the nucleation and growth of Ga-oxide nanostructures can be designer controlled so as to obtain a number of functional properties for photonic applications. However, despite planar geometry pertains to a large part of modern technology, no information is available yet on the scalability of Ga-oxide segregation mechanisms in oxide thin films. In fact, incorporated Ga-oxide nanostructures have only been obtained in bulk materials. Here we show that deposition of Ga-alkali-germanosilicate thin films by radiofrequency-plasma sputtering gives rise to Ga-oxide nanostructures incorporated in an amorphous matrix. X-ray diffraction, X-ray reflectivity, small-angle X-ray scattering, and atomic force microscopy data unveil the formation of lenticular nanoaggregates, only a few nm thick, even in as-deposited materials as a result of two-dimensional aggregation of spinel-like Ga2O3 nanoparticles. Importantly, the aggregate size distribution is controlled not only by the temperature but also by the film thickness when it is reduced from 102 nm to only a few nm. The results open the way to the design of oxide-in-oxide thin films with incorporated networks of nanostructures which can act as percolation paths for unconventional electric responses in neuromorphic functional systems.

Room-temperature synthesis of γ-Ga2O3 nanoparticles from gallium metal via ultrasound irradiation

In this study, gallium oxide (Ga2O3) nanoparticles were synthesized by sonochemical techniques at room temperature. We investigate the ultrasound irradiation conditions and the solvent type to synthesize Ga2O3 nanoparticles. γ-Ga2O3 nanoparticles were synthesized by irradiating gallium metal with ultrasound in hydrazine monohydrate solvent. The irradiation of hydrazine with ultasound suppresses the generation of ·OH, and GaOOH was not formed, and gallium metal directly oxidized. When the synthesized γ-Ga2O3 nanoparticles were heat-treated, a transition to β-Ga2O3 was observed. The heat-treated Ga2O3 nanoparticles showed excellent photocatalytic activity for the decomposition of RhB under UV irradiation.

Novel gallium oxide/reduced graphene oxide nanocomposite for ammonia gas sensing application

Gallium oxide (Ga2O3) nanoparticles was prepared by ultrasonic irradiation of gallium followed by calcination at 900 °C and Ga2O3/reduced Graphene Oxide (rGO) nanocomposites were synthesized by hydrothermal method. The Ga2O3 nanoparticles were mesoporous in nature, with crystallite size around 25 nm, whereas those of nanocomposites (Ga2O3 decorated on rGO) varies from 22 to 24 nm. The nanocomposites were coated onto fluorine doped tin oxide substrates using doctor blade technique to study ammonia sensing property at room temperature. Ammonia gas sensing response of 64% at room temperature, with excellent stability and selectivity has been achieved for the Ga2O3/rGO nanocomposite.

Dehydrogenation of propane over sugar foams templated Ga2O3 nanoparticles catalysts

Highly active Ga2O3 nanoparticles catalysts were prepared by one-step oxidative decomposition of gallium nitrate with sucrose-derived carbon foams (SCF) template. The catalysts were investigated by XRD, Ar physisorption, SEM–EDS, HRTEM, TGA, NH3-TPD and 71 Ga MAS NMR. The addition of sucrose facilitated the higher surface area of Ga2O3 nanoparticles and morphological transformation from bulk to flake due to the structure-directing role of the sucrose solution. Moreover, the weak-medium surface acid sites increased by adding sucrose properly, which was related to the larger number of tetrahedral Ga3+ cations. The optimum catalytic activity was achieved over SXCF-Ga2O3 catalysts at the sucrose/Ga2O3 molar ratio of 6 with the propane conversion of 46.63% and propene selectivity of 88.18%.

Effect of Various Nanoparticles (GaF3, ZnF2, Zn(BF4)2 and Ga2O3) Additions on the Activity of CsF-RbF-AlF3 Flux and Mechanical Behavior of Al/Steel Brazed Joints

In this study, brazing AA6061 to Q235 steel using flame brazing was performed with 70.9 wt.% CsF-0.5 wt.% RbF-28.6 wt.% AlF3 fluxes doped with GaF3, ZnF2, Zn(BF4)2 and Ga2O3 nanoparticles, matched with a Zn-15Al filler metal, and the spreadability of the filler metal and the mechanical properties of brazed joints were investigated at the same time. The results showed suitable amounts of GaF3, ZnF2, Zn(BF4)2 and Ga2O3 doped into the base flux could strengthen the filler metal in wetting and spreading on the surface of aluminum alloy and steel to different degrees. The suitable ranges of GaF3, ZnF2, Zn(BF4)2 and Ga2O3, respectively, were 0.0075–0.01 wt.%, 0.0075–0.01 wt.%, 0.0075–0.01 wt.% and 0.009–0.01 wt.%, and the maximum spreading area was obtained via doping with GaF3. The shear strength of brazed joints reached the peak at 126 MPa when 0.075 wt.% GaF3 was added. Comparative tests proved that the activity of the CsF-RbF-AlF3 flux doped with GaF3 was the best. The reason was that the CsF-RbF-AlF3-GaF3 flux was competent in removing oxides of the base metal and decreasing the interfacial tension, in virtue of the activity of Ga3+ as well as F−.

Gallium oxide nanoparticles prepared through solid-state route for efficient photocatalytic overall water splitting

Gallium oxide (Ga2O3) is one of the most efficient photocatalysts for the overall water splitting. Doping with appropriate metal cations substantially boosts the quantum yield to split water into H2 and O2. In this research, Ga2O3 nanoparticles in the β polymorph (β-Ga2O3) are successfully prepared through a solid-state route under heat treatment. The size of the photocatalyst particles is sufficiently small to shorten the migration distance of the photoexcited charge carriers from the bulk to the surface. To beneficially modify the bulk state of β-Ga2O3, doping with various metals including alkaline-earth metals and first row transition metals is performed. The alkaline-earth metal cations generally increase the water splitting activity. On the other hand, the first row transition metal cations decrease the activity, except for Zn. No systematic trend is observed on the water splitting activity of β-Ga2O3 doped with metal cations in the same group or in the same period. The oxidation state of the dopants plays a role in dictating the water splitting activity. Doping with metal cations having oxidation states lower and higher than that of Ga increases and decreases the activity, respectively. In particular, doping with Zn considerably increases the water splitting activity. At a Zn amount of 1 mol% in the presence of Rh0.5Cr1.5O3 (0.5 wt% Rh) co-catalyst, the H2 and O2 evolution rates can reach as high as 400 and 195 μmol h―1, respectively, with a H2/O2 molar ratio of 2 under UV irradiation with an average intensity of 58 mW cm−2 at 254 nm.

Photocatalytic visible-light-driven removal of the herbicide imazapyer using nanocomposites based on mesoporous TiO2 modified with Gd2O3

In this work, mesoporous Gd2O3-TiO2 nanocomposites synthetized by a sol–gel with vary Gd2O3 concentration were investigated for photo-destruction of imazapyr herbicide waste. Textural, structural and surface properties of the synthetized nanocomposites are verified by N2 physisorption, X-ray diffractometry, HRTEM and various spectroscopic techniques (FTIR, DRS UV–Vis, Raman, PL and XPS). HRTEM micrographs of the calcined Gd2O3-TiO2 revealed the existence of a mesoporous matrix consisting of homogeneously distributed TiO2 nanoparticles (NPs, 12 nm) which are decorated with Ga2O3 nanoparticles. It was found a reverse correlation between the amount of Gd2O3 concentration and the TiO2 nanoparticle size: the formation of smaller TiO2 nanoparticles was favored by the use of high Gd2O3 concentration. The photocatalytic efficiency of the synthetized Gd2O3-TiO2 nanocomposites was appraised in the photo-destruction of imazapyr herbicide below visible-light irradiation. The best herbicide destruction was achieved using 3%Gd2O3-TiO2 photocatalyst and degraded the imazapyr herbicide 20.5 and 8.2 times faster than a commercial P25 and non-promoted TiO2, respectively, indicating that modification of TiO2 with Gd2O3 led to a significant improvement of photocatalyst efficiency. This was explained as due to a lessening of the apparent optical bandgap and the formation of a large amount of surface defect states favoring the separation between electrons and holes. Besides its high efficiency, the 3%Gd2O3-TiO2 photocatalyst demonstrated to be recyclable and stable in the visible-light-driven photocatalytic destruction of imazapyr herbicide.

Comparative Study on the Activity of GaF3 and Ga2O3 Nanoparticle-Doped CsF-AlF3 Flux for Brazing 6061 Al/Q235 Steel Joints

The effect of trace amounts of GaF3 and Ga2O3 nanoparticles on the wettability and spreadability of CsF-AlF3 flux matched Zn-15Al filler metal were comparatively studied on 6061 aluminum alloy and Q235 low-carbon steel. The experimental results indicate that appropriate amounts of GaF3 and Ga2O3 added into the flux could significantly promote the Zn-15Al filler metal to wet and spread on the surface of 6061 aluminum alloy and Q235 low-carbon steel. The optimum ranges for GaF3 and Ga2O3 were 0.0075–0.01wt.% and 0.009–0.01 wt.%, respectively. Comparative analysis showed that the activity of CsF-AlF3 flux bearing GaF3 was higher than that bearing Ga2O3. The reason for this is that the former flux has a stronger ability to remove oxides of the base metal and reduce the interfacial tension of the molten filler metal and the base metal.

Optical insights of indium-doped β–Ga2O3 nanoparticles and its luminescence mechanism

Undoped and In3+ doped β–Ga2O3 nanoparticles have been synthesized at 900 °C using polyol-mediated technique. The effect of Indium dopant on structural, morphological and photoluminescence properties of β–Ga2O3 nanoparticles were investigated in detail. X-ray diffraction patterns demonstrate the monoclinic crystalline structure and indium doping leads to substantial changes in the lattice parameters of β–Ga2O3 nanoparticles. The scanning electron microscope (SEM) images showed reduction in the particle size on doping as due to grain growth inhibition effect. Observed red shift in emission maxima and is increasing with increased In3+ content. Indeed, the shift changes are due to the interactions between donors and acceptors, which are identified as donor–acceptor pair recombination. To understand the red-shift phenomena, we performed time-resolved and steady-state spectroscopic studies for the doped samples. The red shift in the emission maxima of Indium-doped samples was further confirmed with the band gap measurements using absorption spectroscopy and ab initio calculation results.

Two-Dimensional Ga2O3/C Nanosheets as Durable and High-Rate Anode Material for Lithium Ion Batteries.

The self-healing feature of gallium (Ga) is unique, making Ga-based materials attract attention for their potential to solve the anode pulverization issue of lithium ion batteries. In this work, a hierarchical two-dimensional (2D) Ga2O3/C structure has been synthesized by a facile NaCl template method. Ga2O3 nanoparticles (3.8 nm) are uniformly embedded in 2D carbon nanosheets. The long horizontal length of the carbon nanosheets (10 μm) provides long-range electron conductivity, and the thin vertical thickness (75 nm) shortens the Li ion diffusion path. Benefited from the integrated 2D structure and the high electron conductivity, the obtained 2D Ga2O3/C nanosheets exhibit excellent overall performance, including high lithium storage capacity (1026 mAh g-1 at 0.5 A g-1), high rate capability (378 mAh g-1 at 10.0 A g-1), and high cyclability (500 cycles at 0.5 A g-1). The lithiation/delithiation mechanism of 2D Ga2O3/C has been further studied with combined electrochemical and ex situ X-ray diffraction methods.

Near UV excitable warm white light emitting Zn doped γ-Ga2O3 nanoparticles for phosphor-converted white light emitting diode

Optical properties of Zn doped γ-Ga2O3 nanoparticles are investigated for the generation of white light, using near UV LED chip for phosphor-converted WLED (pc-WLED) application. Sol-gel combustion technique is adopted for the synthesis of Zn doped γ-Ga2O3 nanoparticles. The synthesized Ga2O3 nanoparticles are formed as metastable γ-phase with the face-centred cubic crystal structure. The structural stability is maintained up to 15 mol% doping of Zn ions. Formation of aggregated ultrafine particles of undoped and Zn doped γ-Ga2O3 with size less than 4 nm is found from TEM results. Doping of Zn ions has altered the optical band gap of γ-Ga2O3, and it varies from 4.13 to 3.97 eV. Broad visible emission in the wavelength range of 400–600 nm is observed and broadening of emission band increases after Zn doping. Formation of high defect concentration and smaller size of 10 mol% Zn doped γ-Ga2O3 nanoparticles resulted in higher emission intensity. Wide photoluminescence excitation band from 330 to 475 nm suggests that wide visible emission can be obtained from Zn doped γ-Ga2O3 nanoparticles with the excitation of both near UV and blue light. The bi-exponential behavior of PL decay curves of emission bands at the blue and yellow region indicated the complicate luminescence process of Zn doped γ-Ga2O3. The estimated lifetime of blue emission varies from 30 to 37 ns and of yellow emission varies from 54 to 62 ns. Under the excitation of 375 nm LED chip, warm white light emission with CIE color coordinates of (0.42, 0.33), color rendering index of ~ 87 and CCT of 2365 K is obtained for 10 mol% Zn doped γ-Ga2O3 nanoparticles which exemplifying its potential application in pc-WLED fabrication.

Sol- gel synthesis of Ga2O3 nanorods and effect of precursor chemistry on their structural and morphological properties

Synthesis of mono-crystalline Ga2O3 Nanorods was done by sol-gel transformation of gallium(III) isopropoxide (Ga(OPri)3). XRD studies were done to determine the planes and crystal structure of synthesized nanorods that showed the synthesis of β-Ga2O3(a). TEM studies of synthesized Ga2O3 confirmed the synthesis of monocrystalline β-Ga2O3 nanorods. To study the effect of precursor chemistry and to determine role of precursor structures on the crystal structure, phase and morphology of the Ga2O3, a new modified precursor complex was synthesized. The reaction of Ga(OPri)3 with N-phenylsalicylaldimine, [C6H4(OH)CH=N(C6H5)] in 1:1 M ratio yielded [{(H5C6)N = CH-C6H4O}Ga(OPri)2]. The newly synthesized complex was characterized by elemental analyses, molecular weight measurement, FT-IR and NMR (1H and 13C) spectral studies. Spectral studies of the modified complex suggest the presence of bi-dentate mode of attachment of Schiff's base in the solution state. Sol-gel transformations of [{(H5C6)N = CH-C6H4O}Ga(OPri)2] in organic medium, yielded γ-Ga2O3(b), as found by XRD studies. TEM image of the sample (a) revealed the formation of nano-rods of oxide with average diameter of ~100 nm whereas the TEM image of sample (b) showed presence of nano-sized particles of oxide with average particle size of 10 nm. Morphological and compositional studies of synthesized samples (a) and (b) were carried out using SEM and EDX. The method provides a possibility of large scale synthesis of dissimilar shaped and pure Ga2O3 nanoparticles.