Solid Grinding Method Research Articles

Carbon Dots: A Multifunctional Nano‐Sized Giant Tool for the Detection Probe and Physical Reformation of NiMoO4 in Solid‐State for Enriched Energy Storage Application

AbstractDesigning low‐cost, effective and greener materials via a non‐sophisticated strategy is most important for future research. Here, they made a new dual endeavor using carbon dots (CDs) as an environment protection probe for selective detection of environmental toxins, followed by the solid‐state structural reformer to prepare NiMoO4 (NM) via mechanochemical‐based solid grinding method. The prepared CDs, NM and NM‐CDs combination is examined through various techniques. The prepared CDs selectively detect Cr6+, Ru3+, and Doxycycline independently. Also, in this work, a groundbreaking strategy is found to prepare morphology‐tailored NM using CDs through a solid‐state grinding method without adding any other toxic solvents or reagents. The CDs‐induced NM‐CDs (15) look like a 2D nano‐sheet with enriched surface area compared to its bare NM. The fabricated electrode provides the highest capacitance value of 1947 F g−1, almost three times grander than the bare 1D rod‐like electrode. Then, fabricated asymmetric supercapacitor NM‐CDs (15)//AC system delivers a high energy density of 43.9 Wh Kg−1 at a power density of 684 W Kg−1. Overall, a single CDs serve multiple roles in the environment and energy applications with a greener structure tailoring agent and a better booster for re energy storage properties.

Supported gold nanoparticles prepared from NHC-Au complex precursors as reusable heterogeneous catalysts

Gold nanoparticles supported on SiO2, Al2O3, TiO2, and carbon (Maxsorb, Ketjen black and Shirasagi New Gold) were prepared by impregnation and solid grinding methods using N-heterocyclic carbene (NHC)-Au complexes as precursors. A total of nine NHC-Au complex precursors were tested by impregnation and solid grinding method, and [Au(OH)(IPr)] (IPr = 1,3-bis(2,6-diisopropylphenyl)1,3-dihydro-2H-imidazol-2-ylidene) complex led to (1–2 nm) particle sizes by both methods. The prepared catalysts were characterized by XRD (X-ray diffraction), HAADF-STEM (high-angle annular dark-field scanning transmission electron microscopy), in situ XAFS (X-ray absorption fine structure), etc. In addition, [Au(OH)(IPr)] and its impregnated [Au(OH)(IPr)]/SiO2 were subjected to TG-DTA (thermogravimetry analysis-differential thermal analysis) and in situ XAFS analysis under calcination conditions, respectively. Moreover, the obtained supported Au nanoparticles (NPs) were effective as catalysts for low-temperature CO oxidation, intramolecular cyclization of alkynyl carboxylic acids, and isomerization of allylic esters. Their results suggested that the reduction of [Au(OH)(IPr)] proceeds rapidly from around 300°C, and the residual ligands should be attached to the surface of the Au NPs and protect them from drastic agglutination. These results reveal that properly designed NHC-Au complexes can facilitate the preparation of supported Au NP catalysts with small particle sizes and high activities.

Direct Z-scheme heterojunction rutile-TiO2/g-C3N4 catalyst constructed by solid grinding method for photocatalysis degradation

Schematic illustration of RhB photocatalytic reaction mechanism over the rutile-TiO 2 /g-C 3 N 4 photocatalyst. • The rutile-TiO 2 /g-C 3 N 4 photocatalyst is constructed by a simple solid grinding method. • The optimized rutile-TiO 2 /g-C 3 N 4 photocatalyst has more excellent photocatalytic performance than the pure rutile-TiO 2 and g-C 3 N 4 . • The direct Z-scheme heterojunction mechanism is proposed over the rutile-TiO 2 /g-C 3 N 4 photocatalyst. Constructing a direct Z-scheme heterojunction is an effective method to improve the catalytic performance of photocatalyst. Here, the direct Z-scheme heterojunction rutile-TiO 2 /g-C 3 N 4 photocatalyst was constructed by a simple solid grinding method. This method can not only avoid the weak activity of rutile-TiO 2 in high synthesized temperature condition, but also precisely control the amount of g-C 3 N 4 . The evaluation of photodegradation reaction suggests that the rutile-TiO 2 /g-C 3 N 4 photocatalyst exhibits higher photodegradation efficiency than the pure rutile-TiO 2 and the pure g-C 3 N 4 under simulated sunlight irradiation, and the optimal photocatalytic performance is achieved when the mass ratio of rutile-TiO 2 to g-C 3 N 4 is 2:5. The experimental results prove that a direct Z-scheme heterojunction is formed over the rutile-TiO 2 /g-C 3 N 4 photocatalyst, which promotes the effective electron-hole separation and the higher redox potential over the rutile-TiO 2 /g-C 3 N 4 photocatalyst. This work provides an attractive strategy to construct the direct Z-scheme photocatalyst consisted of rutile-TiO 2 and g-C 3 N 4 .

Solvent-Free Green Synthesis of Cu0.5Ti2(PO4)3 and Cu0.5TiO(PO4) NASICON-Type Compounds from Ilmenite Mineral Sand

Ilmenite is a naturally available black or steel-gray color mineral, called titanium iron oxide, FeTiO3.This valuable mineral comprises a significant amount of titanium that can be utilized as a titanium source to synthesize various materials. This study focused on synthesizing copper titanium phosphate compounds via an eco-friendly solid-state reaction route. α-titanium bismonohydrogen orthophosphate monohydrate (α-Ti(HPO4)2.H2O/α-TiP), derived from beach sand ilmenite used as the starting material for the synthesis. α-TiP was obtained by digesting ilmenite with 85 wt% phosphoric acid under reflux conditions. The XRD pattern of the obtained white powder confirmed the formation of α-TiP. The synthesized α-TiP and copper (Ⅱ) acetate were ground with different molar ratios (1:2, 1:1, and 2:1) until it forms a fine powder following a solvent-free solid grinding method. These powder mixtures were calcined at 800 °C for 4 hours utilizing a muffle furnace. The obtained solid solutions developed green and two different shades of yellow color. The samples werecharacterized by XRD, Thermogravimetry (DSC/TGA) techniques, and Raman spectroscopy. The XRD results revealed the formation of solid solutions containing copper titanium phosphate (Cu0.5Ti2(PO4)3) at 1:1 and 2:1 molar ratios of α-TiP to copper (Ⅱ) acetate while the products obtained at 1:2 and 1:1 molar ratios confirmed the formation of copper titanium oxyphosphate (Cu0.5TiOPO4). Moreover, TGA results confirm the development of these mixed metal phosphates which can be further analyzed for applications in the ceramic industry. Therefore, calcination of the reaction mixtures by changing the molar ratios produced different colored stable compounds that can potentially be used as ceramic pigments, coatings, and electrode materials.
 Keywords: Copper titanium phosphate, α-titanium bismonohydrogen orthophosphate monohydrate, Solid-state reaction route

Gold Nanoparticles Supported on Nb2O5 for Low-Temperature CO Oxidation and as Cathode Materials for Li-ion Batteries

We prepared a series of Nb2O5 polymorphs by the sol-gel method and the sol-gel hydrothermal method. Gold nanoparticles supported on Nb2O5 were prepared by solid grinding method. Au on pseudohexagonal (TT-phase) Nb2O5 containing an amorphous phase exhibited higher catalytic activity for CO oxidation than did other Au/Nb2O5 polymorphs. For the electrochemical properties for cathode materials of Li-ion batteries, Nb2O5 (TT) exhibited high capacity of 208 mA h g-1, and the deposition of Au onto Nb2O5 (TT) improved the capacity to 232 mA h g-1. Capacity and CO oxidation activity were related; the higher the catalytic activity Au/Nb2O5 shows, the higher is the discharging capacity. From the characterization results, Nb2O5 (TT) contains oxygen vacancies (Nb4+ sites), and the oxygen vacancies of Nb2O5 (TT) would play an important role for CO oxidation and the performance for Li-ion batteries.

Pharmaceutical Cocrystal Development of TAK-020 with Enhanced Oral Absorption

The objective of this study was to improve the solubility of poorly water-soluble drugs by pharmaceutical cocrystal engineering techniques and select the best pharmaceutical forms with high solubility and solubilized formulations for progress from the early discovery stage toward the clinical stage. Several pharmaceutical cocrystals of TAK-020, a Bruton tyrosine kinase inhibitor, were newly discovered in the screening based on the solid grinding method and the slurry method, considering thermodynamic factors that dominate cocrystal formation. TAK-020/gentisic acid cocrystal (TAK-020/GA CC) was selected based on a physicochemical property of enhanced dissolution rate. TAK-020/GA CC was proven to be a reliable cocrystal formation with a definitive stoichiometric ratio by a variety of analytical techniques—pKa calculation, solid-state nuclear magnetic resonance, and single X-ray structure analysis from the view of regulation. Furthermore, its absorption was remarkable and beyond those achieved in currently existing solubilized formulation techniques, such as nanocrystal, amorphous solid dispersion, and lipid-based formulation, in dog pharmacokinetic studies. TAK-020/GA CC was the best drug form, which might lead to good pharmacological effects with regard to enhanced absorption and development by physicochemical characterization. Through the trials of solid-state optimization from early drug discovery to pharmaceutical drug development, the cocrystals can be an effective option for achieving solubilization applicable in the pharmaceutical industry.

A novel UiO-66 encapsulated 12-silicotungstic acid catalyst for dimethyl ether synthesis from syngas

Abstract Dimethyl ether (DME) has received great attention as a promising clean fuel and industrially important intermediate. Tremendous efforts have been made to develop highly active and stable catalysts for DME production. Here, we present the first example of the application of metal-organic framework (MOF) catalyst in DME synthesis from syngas. A Zr-MOF (UiO-66) was selected as the catalyst host and support owing to its exceptionally high stability and porosity. UiO-66 was firstly functionalized by silicotungstic acid (H4SiW12O40, STA) via a one-pot synthesis method and then loaded with Cu by a facile solid grinding method. The prepared catalysts were characterized using XRD, TGA, FT-IR, N2 adsorption and TEM. The high porosity and thermal stability of acidified UiO-66 were maintained after 15% wt STA incorporation without any destruction of the Keggin structure of STA. The catalyst was tested for one step DME synthesis from syngas, showing higher DME selectivity and space-time yield than control catalysts. The superior activity of Cu/STA-UiO was attributed to the uniform dispersion of active centres with close intimacy and high density of Bronsted acid sites, as well as strong metal support interaction between Cu and Zr oxide SBU evidenced by XPS analysis.

Activation of solid grinding-derived Au/TiO2 photocatalysts for solar H2 production from water-methanol mixtures with low alcohol content

Au/TiO2 nanocomposites are prepared by the solventless solid grinding method, which consists in mechanically mixing AuPPh3Cl and titania P25 and applying a mild heat treatment to reduce Au (I) into Au (0) nanoparticles (Au NP). Given that gold oxides are not thermally stable, both air and hydrogen can be considered for such treatment. Air however leads to much more efficient photocatalysts than hydrogen, due to a more efficient degradation of the gold complex, as shown by X-ray photoelectron spectroscopy, and a more effective Au-TiO2 interface. Amongst the investigated gold loadings, the composite containing 0.5wt.% Au 0.5Au/TiO2[air] appears as the most active, yielding about 500μmolH2h−1g−1 under simulated solar light in the presence of 1vol.% methanol. This represents a marked improvement in terms of noble metal utilization, as compared with the 2wt.% Au/TiO2 benchmarks. The yet highest efficiency (in terms of Au-normalized H2 production) of 0.1Au/TiO2[air] (54h−1), and the different trend observed with higher surface area titania, highlights the key role of the Au NP density in the photocatalytic process.

A Simultaneous Solid Grinding Method for the Preparation of Gold Catalysts

Au–Ag bimetallic catalysts on SiO2 were prepared using a simultaneous solid grinding (simul-SG) method, in which multiple kinds of organometallic complexes are ground with a support powder. After optimizing the Ag/Au ratio, the obtained catalysts exhibited remarkably high activity for low-temperature CO oxidation compared with that of Au/SiO2 or Ag/SiO2 catalysts. A detailed structural analysis using electron microscopy revealed that a higher ratio of Ag prevents growth of the particles via sintering and induces high densities of active Au–Ag contacts. Our simul-SG method is a promising tool for the easy preparation of multicomponent catalysts on various supports.

Ni–M–O (M = Sn, Ti, W) Catalysts Prepared by a Dry Mixing Method for Oxidative Dehydrogenation of Ethane

A new generation of Ni–Sn–O, Ni–Ti–O, and Ni–W–O catalysts has been prepared by a solid-state grinding method. In each case the doping metal varied from 2.5% to 20%. These catalysts exhibited higher activity and selectivity for ethane oxidative dehydrogenation (ODH) than conventionally prepared mixed oxides. Detailed characterization was achieved using XRD, N2 adsorption, H2-TPR, SEM, TEM, and HAADF-STEM in order to study the detailed atomic structure and textural properties of the synthesized catalysts. Two kinds of typical structures are found in these mixed oxides, which are (major) “NixMyO” (M = Sn, Ti, W) solid solution phases (NiO crystalline structure with doping atom incorporated in the lattice) and (minor) secondary phases (SnO2, TiO2, or WO3). The secondary phase exists as a thin layer around small “NixMyO” particles, lowering the aggregation of nanoparticles during the synthesis. DFT calculations on the formation energies of M-doped NiO structures (M = Sn, Ti, W) clearly confirm the thermodynamic feasibility of incorporating these doping metals into the NiO struture. The incorporation of doping metals into the NiO lattice decreases the number of holes (h+) localized on lattice oxygen (O2– + h+ → O•–) , which is the main reason for the improved catalytic performance (O•– is known to favor complete ethane oxidation to CO2). The high efficiency of ethylene production achieved in these particularly prepared mixed oxide catalysts indicates that the solid grinding method could serve as a general and practical approach for the preparation of doped NiO-based catalysts.

High Activity of Gold/Tin-Dioxide Catalysts for Low-Temperature CO Oxidation: Application of a Reducible Metal Oxide to a Catalyst Support

Au/SnO2 catalysts were prepared by both the solid grinding (SG) method and the deposition precipitation (DP) method. Compared to samples prepared by the DP method, the SG samples showed remarkably high activity for low-temperature CO oxidation, because of a more efficient Au deposition on SnO2 by the SG method. Detailed analysis revealed that the perimeter interface between Au and SnO2 is the active site for catalysis. The present results suggest that the activity of Au/oxide catalysts is associated with the reducibility of the metal oxide supports at the perimeter interface.

Aerobic oxidation of glucose over gold nanoparticles deposited on cellulose

Gold nanoparticles (NPs) with mean diameters of around 2 nm could be deposited directly onto a bio-polymer, cellulose, by the solid grinding method with volatile dimethyl Au(III)acetylacetonate followed by the reduction with H 2. Gold NPs on cellulose showed appreciably high catalytic activity with a turnover frequency (TOF) of 11 s −1 for the aerobic oxidation of glucose to produce sodium gluconate at 60 °C and at pH 9.5. The catalytic activity of Au/cellulose was comparable to that of Au/C provided the size of the Au particles was similar.

One-potN-alkylation of primary amines to secondary amines by gold clusters supported on porous coordination polymers

Gold clusters and nanoparticles were deposited on the three kinds of porous coordination polymers (PCP5), MOF-5, CPL-2, and AI-MIL53 by the solid grinding method. The size of Au particles depended on the kinds of PCPs and increased in the order of AI-MIL53 < CPL-2 < MOF-5. The mean diameter of Au particles supported on AI-MIL53 was estimated to be 1.6 nm by HAADFSTEM. Such small Au clusters on AI-MIL53 can catalyze one-pot synthesis of secondary amines from primary amines by sequential oxidation/hydrogenation owing to the remarkable improvement of hydrogenation efficiency of imine. Gold clusters deposited on AI-MIL53 can also promoteN-alkylation of amine with alcohol to form a secondary amine under N2 atmosphere without using O2 and H2.

Deposition of gold nanoparticles on carbons for aerobic glucose oxidation

Carbon materials such as activated carbon and carbon black have long been used as adsorbents, electrodes, and supports for metal catalysts. However, no attempt has yet been reported to deposit Au as small nanoparticles (NPs) on these carbon materials directly from Au precursor compounds. Until now, the most effective way to support Au NPs on activated carbon was to physically mix a carbon support with Au colloids prepared beforehand. Here we report that Au could be deposited as NPs on carbon materials directly from gold precursor compounds by deposition reduction method and by solid grinding method. In particular, the solid grinding of carbons with dimethyl Au(III) acetylacetonate, which has a certain degree of vapor pressure at room temperature, is a simple technique but surprisingly effective to deposit Au NPs with a mean diameter as small as 1.9 nm. These highly dispersed Au NPs on carbon supports were tested for glucose oxidation in water with molecular oxygen. A Au/nanoporous carbon (NPC) catalyst which exhibited relatively high catalytic activity has been kinetically studied for comparison with Au/metal oxides catalysts.

Au@ZIF-8: CO Oxidation over Gold Nanoparticles Deposited to Metal−Organic Framework

Gold nanoparticles (NPs) were deposited to a zeolite-type metal-organic framework (MOF) by a simple solid grinding method. A catalyst, Au@ZIF-8, represents the first example of an active catalyst in CO oxidation by using a MOF as a novel support for noble metal NPs. The catalytic activity for CO oxidation is improved along with increasing Au loadings, and the highest catalytic activity is obtained for 5.0 wt % Au@ZIF-8, which presents half conversion of CO at approximately 170 degrees C. Gold NPs are close to being monodisperse and have no aggregation during catalytic reaction, and the catalytic activity is reproducible.

Creating the adsorptive sites with high performance toward nitrosamines in mesoporous silica MCM-41 by alumina modifier

Toward the aim of matching to zeolite in adsorption of small pollutant molecules such as volatile nitrosamines in environment, MCM-41, the mesoporous silica with the relative small pore size, was chosen to be modified with alumina through one-pot synthesis, solvent-free solid grinding and gel-mixing methods, in order to optimize the adsorptive capability of mesoporous composite. To study how the preparative method affects the structure and function of the modified MCM-41 in detail, XRD, N 2 adsorption–desorption, 27Al MAS NMR, FTIR and NH 3-TPD techniques were employed to characterize the resulting composites, and the adsorption of NPYR ( N-nitrosopyrrolidine) and NNN ( N-nitrosonornicotine) was employed to assess the adsorptive capability of Al-containing MCM-41. Modification with alumina significantly increased the ability of MCM-41 to trap NPYR, and among various preparations the solvent-free solid grinding method was able to disperse alumina guest with high accessibility and to reserve surface silanol groups on MCM-41. Typically, the Al 2O 3/MCM-41 composite synthesized by solvent-free method with 12 wt.% alumina exhibited a capacity comparable to zeolite NaY for trapping NPYR in airflow but four times superior to NaY for adsorbing bulky nitrosamine NNN in solution. Finally, a proposal how to establish high adsorption performance in mesoporous silica was suggested.