Low-temperature Method Research Articles

Exhumation of the Cuonadong Sn–W–Be polymetallic deposit, Tethyan Himalaya: Implications for exploration

The Cuonadong Sn–W–Be polymetallic ore deposit is the first rare-metal deposit related to leucogranites with giant mineralization potential to be discovered in the Himalayan Orogen. However, the post-mineralization exhumation and preservation processes of this deposit have not yet been studied in detail, although these factors are key to the exploration and evaluation of rare-metal deposits in the Himalaya. Geophysical data have revealed that a hidden fault (i.e., the Jisong secondary fault) cuts the southern part of the Cuonadong ore deposit. In order to determine the effects of the Jisong secondary fault on the exhumation of the Cuonadong deposit, we undertook zircon and apatite (U–Th)/He dating, apatite fission-track dating, and forward and inverse thermal history modeling of the footwall and hanging wall of the Jisong secondary fault. Our results show that the Cuonadong deposit experienced two stages of rapid, post-mineralization exhumation at ca. 10–9 and ca. 5–4 Ma, separated by a period of differential exhumation at ca. 9–5 Ma. These exhumation events were likely caused successively by the arc-shaped Nading Fault, normal faulting on the Jisong secondary fault, and thrusting on the Main Himalayan Thrust, although climate-related erosion may have also had a role in the exhumation. Owing to normal displacement on the Jisong secondary fault, the Cuonadong ore deposit underwent differential exhumation of 300–700 m. This implies that the eastern part of the deposit is more favorable for exploration than its western part if the deposit has the same mineralization depth. This study demonstrates that low-temperature thermochronological methods can be useful in the exploration for rare-metal deposits in the Himalayan Orogen.

One-step synthesis of orange-red emissive carbon dots: photophysical insight into their excitation wavelength-independent and dependent luminescence.

A low-temperature method was developed to synthesize orange-red luminescence phosphor-doped carbon dots (CDs) without complicated purification procedures. These CDs showed excitation wavelength-independent narrow emission (photo-luminescence quantum yield, Φf ∼ 12 to 22%) with single exponential time-resolved decay in weakly polar/non-polar solvents, indicating the presence of one kind of chromophore. In contrast, the same CDs showed excitation wavelength-dependent broad emission (Φf ∼ 1 to 8%) with multi-exponential fluorescence decay in polar solvents. These CDs exhibited poor solubility in polar solvents, resulting in CD aggregates contributed by excitation wavelength-dependent weak luminescence. The CDs embedded in polymethyl methacrylate (PMMA) polymer film displayed bright orange-red fluorescence under UV 365 nm illumination, indicating their potential application in solid-state luminescence. Further, an analytical method was developed for the naked-eye detection of trifluoracetic acid (red emission) and triethylamine (green emission) under UV 365 nm illumination with reversible two switch-mode luminescence. Additionally, this efficient orange-red luminescence of CDs was utilized for possible bioimaging applications with negligible cytotoxicity in 3T3 mouse fibroblast cells.

Pioneering the preparation of porous PIM-1 membranes for enhanced water vapor flow.

In this study, porous polymers of intrinsic microporosity (PIM-1) membranes were prepared by non-solvent induced phase inversion (NIPS) and investigated for water vapor transport in view of their application in membrane distillation (MD). Due to the lack of high boiling point solvents for PIM-1 that are also water miscible, the mixture of tetrahydrofuran (THF) and N-methyl-2-pyrrolidone (NMP) was found to be optimal for the formation of a membrane with a developed porous system both on the membrane surface and in the bulk. PIM-1 was synthesized by using low and high temperature methods to observe how molecular weight effects the membrane structure. Low molecular weight PIM-1 was produced at low temperatures, while high molecular weight PIM-1 was obtained at high temperatures. Several membranes were prepared, including PM-6, PM-9, and PM-11 from low molecular weight PIM-1, and PM-13 from high molecular weight PIM-1. Scanning electron microscopy (SEM) was used to image the surface and cross-section of different porous PIM-1 membranes. Among all the PIM-1 membranes (PM) obtained, PM-6, PM-9, PM-11 and PM-13 showed the most developed porous structure, while PM-13 showed large voids in the bulk of the membrane. Contact angle measurements showed that all PIM-1 porous membranes are highly hydrophobic. Liquid water flux measurements showed that PM-6, PM-9 and PM-11 showed minimal water fluxes due to small surface pore size, while PM-13 showed a high water flux due to a large surface pore size. Water vapor transport measurements showed high permeance values for all membranes, demonstrating the applicability of the developed membranes for MD. In addition, a thin film composite (TFC) membrane with PIM-1 selective layer was prepared and investigated for water vapor transport to compare with porous PIM-1 membranes. The TFC membrane showed an approximately 4-fold lower vapor permeance than porous membranes. Based on these results, we postulated that the use of porous PIM-1 membranes could be promising for MD due to their hydrophobic nature and the fact that the porous membranes allow vapor permeability through the membrane but not liquid water. The TFC membrane can be used in cases where the transfer of water-soluble contaminants must be absolutely avoided.

Solution-phase synthesis of alloyed Ba(Zr1-xTix)S3 perovskite and non-perovskite nanomaterials.

Chalcogenide perovskites, especially BaZrS3 and its related alloys, present a promising alternative to lead halide perovskites for optoelectronic applications due to their reduced toxicity and enhanced stability. However, the elevated temperature conditions necessary for preparing these materials create a barrier to their incorporation into thin-film devices. In this work, we report a solution-phase synthesis of colloidal nanoparticles of titanium-alloyed BaZrS3, Ba(Zr1-xTix)S3. The titanium alloying was achieved using reactive amide precursors in oleylamine solvent, and N,N'-diethylthiourea served as the sulfur source. Our methodology allowed for the synthesis of Ba(Zr1-xTix)S3 nanomaterials at temperatures at or below 300 °C. The resulting nanocrystals exhibited a phase transition from an orthorhombic distorted perovskite structure to a hexagonal non-perovskite phase as the titanium content surpassed x = 0.11, accompanied by a morphological evolution from nanoplatelets to nanohexagons and ultimately nanobars. The UV-Vis-NIR absorption spectra of Ba(Zr1-xTix)S3 nanoparticles exhibit increasing low-energy absorption as the titanium content is increased. This work contributes to the development of low-temperature synthesis methods for Ba(Zr1-xTix)S3 nanomaterials, offering new potential pathways for materials design of chalcogenide perovskites for advanced optoelectronic applications.

Porous tremella-like NiMoP/CoP network electrodes as an efficient electrocatalyst.

The design of efficient, stable and cost-effective electrocatalysts for the hydrogen evolution reaction holds substantial significance in water electrolysis, but it remains challenging. Tremella-like nickel-molybdenum bimetal phosphide encapsulated cobalt phosphide (NiMoP/CoP) with hierarchical architectures has been effectively synthesized on nickel foam (NF) via a straightforward hydrothermal followed by low-temperature phosphating method. Based on the unique structural benefits, it significantly increases the number of redox active centers, enhances the electrical conductivity of materials, and diminishes the ion diffusion path lengths, thereby promoting efficient electrolyte penetration and reducing the inherent resistance. The as-obtained NiMoP/CoP/NF electrocatalyst exhibited remarkable catalytic activity with an ultralow overpotential of 38 mV (10 mA cm-2) and low Tafel slope of 83 mV dec-1. The straightforward synthesis process and exceptional electrocatalytic properties of NiMoP/CoP/NF demonstrate great potential for the HER to replace the precious metal catalyst.

Patterned graphene oxide via one-step thermal annealing for controlling collective cell migration.

Graphene oxide (GO) is a two-dimensional metastable nanomaterial. Interestingly, GO formed oxygen clusterings in addition to oxidized and graphitic phases during the low-temperature thermal annealing process, which could be further used for biomolecule bonding. By harnessing this property of GO, we created a bio-interface with patterned structures with a common laboratory hot plate that could tune cellular behavior by physical contact. Due to the regional distribution of oxygen clustering at the interface, we refer to it as patterned annealed graphene oxide (paGO). In addition, since the paGO was a heterogeneous interface and bonded biomolecules to varying degrees, arginine-glycine-aspartic acid (RGD) was modified on it and successfully regulated cellular-directed growth and migration. Finally, we investigated the FRET phenomenon of this heterogeneous interface and found that it has potential as a biosensor. The paGO interface has the advantages of easy regulation and fabrication, and the one-step thermal reduction method is suitable for biological applications. We believe that this low-temperature thermal annealing method would make GO interfaces more accessible, especially for the development of nano-interfacial modifications for biological applications, revealing its potential for biomedical applications.

A N-doped carbon substrate makes the Ru-Co alloy an efficient electrocatalyst for pH-universal seawater splitting.

Designing electrocatalysts for seawater splitting remains challenging. A Ru-Co alloy supported by an N-doped carbon substrate catalyst has been designed using etching and a low-temperature treatment method. Studies show that the superior performance of this catalyst is related to the hollow-structured N-doped carbon frame and surface reconstruction of the Ru-Co alloy.

Application of Aronia Melanocarpa Fruit Powder Obtained by an Innovative Low-Temperature Drying Method for Facial Care Masks

Application of Aronia Melanocarpa Fruit Powder Obtained by an Innovative Low-Temperature Drying Method for Facial Care Masks

Water-dispersible fluorescent COFs disturb lysosomal autophagy to boost cascading enzymatic chemodynamic-starvation therapy.

Cascading enzymatic therapy is a promising approach in cancer treatment. However, its effectiveness is often hindered by enzyme inactivation, limited exposure of active sites, cancer cell self-protection mechanisms such as autophagy, and non-specific toxicity, which can lead to treatment failure. To address these challenges, we used a low-temperature aqueous-phase synthesis method to create semi-crystalline, water-dispersible fluorescent COF nanospheres. These nanospheres can stably load glucose oxidase (GOx) and ultrafine Fe2O3 nanozymes, allowing for convenient coating with tumor cell membranes to form a uniform tumor-targeted cascading enzymatic nanosystem (CFGM). This system promotes a cycle of tumor glucose depletion, reactive oxygen species (ROS) generation, and oxygen production, facilitating tumor-targeted starvation therapy (ST) and chemodynamic therapy (CDT). Notably, the semi-crystalline COF carrier within this system can degrade slowly under mildly acidic conditions, forming large aggregates that damage lysosomes and disrupt lysosomal autophagy, thereby eliminating the autophagy protection of cancer cells activated by the combined ST. This synergistic approach enhances the catalytic inhibition of tumors. Our research thus provides an alternative COF-based platform and strategy for effective cancer treatment.

Photo-assisted epitaxial growth from nanoparticles to enhance multi-materialization for advanced surface functionalization.

To meet the requirements of freeform objects, a wide range of highly designable resin-based materials has been created, highlighting the need for low-temperature ceramic deposition methods for surface functionalization. Photo-assisted chemical solution deposition (PCSD), an efficient technique for low-temperature ceramic growth, is used to fabricate thin films via photochemical and photothermal effects. The hybrid-solution-incorporated PCSD (HS-PCSD), in which a hybrid-solution comprising metal-organic compounds and nanoparticles is used in PCSD, has attracted considerable interest as it enables deposition at reduced temperatures and accelerated rates. However, the crystal growth processes in the HS-PCSD remain underexplored, which hinders the design of films using this method. In this study, we quantitatively evaluated the photocrystallization of ceramic thin films that were fabricated under various HS-PCSD conditions. We determined that the laser intensity at the reaction interface must exceed a threshold for epitaxial growth through dangling bond photoactivation and photothermal atomic migration to compete with crystal nucleation growth. We also identified that the particle growth during photocrystallization occurred because of amorphous-phase crystallization and not grain boundary migration. Through these quantitative analyses, we obtained insights into ways to achieve true multi-materialization with desirable physical properties in HS-PCSD.

Nanoengineered parallelogram-NiFe2O4/rGO nanocomposite-based biosensing interface for highly efficient electrochemical detection of neurodegenerative disorders via dopamine monitoring

A low-temperature hydrothermal method for synthesis of unique parallelogram morphology based NiFe2O4 and NiFe2O4/reduced graphene oxide nanocomposite for fabricating biosensors for dopamine monitoring.

Construction of hierarchical In2O3/In2S3-ZnCdS ternary microsphere heterostructures for efficient photocatalytic nitrogen fixation.

Photocatalytic ammonia production holds immense promise as an environmentally sustainable approach to nitrogen fixation. In this study, In2O3/In2S3-ZnCdS ternary heterostructures were successfully constructed through an innovative in situ anion exchange process, coupled with a low-temperature hydrothermal method for ZnCdS (ZCS) incorporation. The resulting In2O3/In2S3-ZCS photocatalyst was proved to be highly efficient in converting N2 to NH3 under mild conditions, eliminating the need for sacrificial agents or precious metal catalysts. Notably, the NH4+ yield of In2O3/In2S3-0.5ZCS reached a significant level of 71.2 μmol g-1 h-1, which was 10.47 times higher than that of In2O3 (6.8 μmol g-1 h-1) and 3.22 times higher than that of In2O3/In2S3 (22.1 μmol g-1 h-1). This outstanding performance can be attributed to the ternary heterojunction configuration, which significantly extends the lifetime of photogenerated carriers and enhances the spatial separation of electrons and holes. The synergistic interplay between CdZnS, In2S3, and In2O3 in the heterojunction facilitates electron transport, thereby boosting the rate of the photocatalytic nitrogen fixation reaction. Our study not only validates the efficacy of ternary heterojunctions in photocatalytic nitrogen fixation but also offers valuable insights for the design and construction of such catalysts for future applications.

Carbothermal reduction assisted by hydrogenation treatment for preparing single-phase CeC2 nanoscale powders

Single-phase CeC2 powders can be successfully prepared through the carbothermal reduction assisted by hydrogenation treatment (CRHT) using 20–50 nm CeO2 as cerium source and 100–200 nm carbon black as carbon source. During the hydrogenation process, the interaction of CeO2 with H2 leads to a partial valence reduction of Ce ions, yielding a partially anoxic phase (CeO1.675) and a hydrogenated phase (CeH2). CeO1.675 can increase the oxygen vacancies required in the reaction process, while CeH2 can produce gas-phase reductant H2 at the reaction temperature, which together promotes the reduction reaction. The results show that the CRHT can obtain single-phase CeC2 powders at a temperature of 1550 °C, which is 100 °C lower than its theoretical temperature. For the preparation of CeC2 powders, the CRHT is a low-temperature and efficient method.

Facile one-step synthesis of a novel Bi2S3/BiOCl0.1Br0.9 S-scheme heterojunction photocatalyst with enhanced photocatalytic performance: function of interfacial electric field

Based on the anion exchange strategy, a novel Bi2S3/BiOCl0.1Br0.9 S-scheme heterojunction was prepared via a facile one-step low-temperature water bath method for the first time.

Enhanced Detection of Benzo[a]pyrene in Olive Oil through Low Temperature Liquid-Liquid Extraction Coupled with Constant Energy Synchronous Fluorescence Spectroscopy

Refined processed olive oil can indeed become significantly contaminated with polycyclic aromatic hydrocarbons (PAHs). To assess exposure to these contaminants, benzo[a]pyrene (B[a]P) is utilized as a marker due to its known carcinogenicity in humans. The European Commission has established a maximum limit of 2 μg kg-1 for B[a]P in edible oils. However, the analysis of trace amounts of B[a]P in a complex matrix like olive oil poses a persistent challenge. In this study, we have developed a low-temperature liquid-liquid extraction method in combination with constant energy synchronous fluorescence analysis for the determination of B[a]P in olive oil samples. The analyte was extracted from the olive oil using a mixture of acetonitrile and acetone. The performance of fluorescence measurements was evaluated by carefully considering the effects of solvent, temperature, acetone quenching, and slit width for monochromators. The proposed method demonstrates a linear range from 0.8 to 3.2 μg kg-1, with limits of detection and quantification of 0.04 and 0.80 μg kg-1, respectively. Precision and trueness assessments revealed relative standard deviations of less than 10% and recovery rates ranging from 103 to 112%. This method presents an efficient and rapid alternative to sample preparation procedure that minimizes organic solvent consumption.

Preparation of implantable drug carrier-ordered porous HA/β-TCP composite

HA/?-TCP composite with good biocompatibility and bioactivity had received attention in the field of implantable drug carrier. In order to improve its drug release performance, HA/?-TCP was prepared using low-temperature precipitation method by adjusting pH value and ordered porous morphology were designed and obtained using template method. Using IBU as the drug model, in vitro drug simulation release experiments were conducted on this materia. With increase of pH value, the IBU-loading capacity of this composite gradually decreased, and at a pH value of 6, the IBU-loading capacity could reach 101.3mg/g. The in vitro simulated IBU release experiment indicated that during the rapid release stage of IBU, the ordered porous composite improved sudden drug release phenomenon to varying degrees and all the composites showed good slow-release performance. The composite obtained at a pH of 6 exhibited the best release of IBU, with a cumulative release rate of 86.35%.

Iron-doping-induced formation of Ni-Co-O nanotubes as efficient bifunctional electrodes.

The rational design of earth-abundant and efficient electrocatalysts to replace precious metal-based materials is highly anticipated for overall water splitting. Herein, NiCo2O4 electrocatalysts with different Fe doping amounts (Fex-NCO, x = 1, 2, 3) were synthesized by a low-temperature chemical method. It was interesting to find that the doping of Fe induced the formation of NiCo2O4 nanotube arrays by modulating the Fe content. The Fe3-NCO electrode with a nanotube structure and rich oxygen vacancies exhibited exceptional electrocatalytic activities for the hydrogen evolution reaction (97 mV, 10 mA cm-2) and oxygen evolution reaction (188.4 mV, 10 mA cm-2). DFT calculations revealed that Fe promoted the modulation of the electronic structure, which played a crucial role in optimizing the reaction intermediates and altered the energy level of the d band center, and as a result, enhanced the water dissociation ability. Additionally, a low cell voltage of 1.56 V (10 mA cm-2) was realized for water splitting based on an as-fabricated Fe-doped NiCo2O4 nanotube array bifunctional electrode.

LOW TEMPERATURE ALUMINIZATION EFFECT ON MONEL 400 ALLOY PRODUCED BY PACK CEMENTATION METHOD

In this study, aluminum coating process was performed on Monel 400 alloy at a temperature of 600°C using the low-temperature pack cementation method for durations of 2, 4, and 6 hours. The mixture for the coating consisted of metallic Al powder as the aluminum source, Al2O3 as the inert filler, and Ammonium Chloride (NH4Cl) as the activator. The formed coatings were characterized using Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) analyses to examine their microstructures, and phase analyses were conducted using and X-Ray Difraction Analyses (XRD). SEM analysis revealed that the coating layers were homogeneous, compact, and pore-free, demonstrating a strong bond between the coating and the matrix. The thickness of the coating layer was measured from the surface to the matrix, and it was observed to vary between 4 µm and 10 µm. It was determined that 600°C was sufficient for the accumulation of an aluminide layer and a successful coating layer was obtained. The hardness values of the alumina layer formed on the surface were measured, and an increase in hardness values was observed with increasing process duration and temperature.

Optical and Electrical Properties of Nano Magnesium Oxide Doped with Polyvinylpyrrolidone (PVP) Thin Films

A thin film of polyvinylpyrrolidone (PVP) polymer doped with different weight ratios of magnesium oxide nanoparticles produced by using the low-temperature hydrothermal method was prepared, and the morphology of the doped thin film was verified using a scanning electron microscope and an atomic force microscope. The X-ray diffraction pattern showed that magnesium oxide has a multi cubic crystal structure with a diffraction peak of high density associated with the level (200) (at the diffraction angle of 42.69◦) and a crystal drop size of 25 nm. Measurements of the Fourier A transformation of the infrared spectrum of a polyvinylpyrrolidone polymer doped with metal oxides was carried out. It showed a clear difference from the pure polymer, where a (Mg-O-Mg) bond appeared at a wavelength of 450 cm^-1 to confirm the effect of MgO addition on the chemical bonding of polyvinylpyrrolidone. Optical properties, including absorbance, maximum wavelength, and energy gap, have been studied. Determined by ultraviolet examination. The band gap decreased when MgO was doped with PVP films, and the Hall coefficient effect was used to calculate the electrical properties, including the conductivity, kinetics of charge carriers, and their type. The highest conductivity was (0.1*10^-2 Sm), and the tainted membrane was of the n type), where it can be used in optical applications.

Impact of Low-Temperature Water Exposure and Removal on Zeolite HY.

Aqueous-phase postsynthetic modifications of the industrially important Y-type zeolite are commonly used to change overall acid site concentrations, introduce stabilizing rare-earth cations, impart bifunctional character through metal cation exchange, and tailor the distribution of Brønsted and Lewis acid sites. Zeolite Y is known to undergo framework degradation in the presence of both vapor- and liquid-phase water at temperatures exceeding 100 °C, and rare-earth exchanged and stabilized HY catalysts are commonly used for fluidized catalytic cracking due to their increased hydrothermal resilience. Here, using detailed spectroscopy, crystallography, and flow-reactor experiments, we reveal unexpected decreases in Brønsted acid site (BAS) density for zeolite HY following exposure even to room-temperature liquid water. These data indicate that aqueous-phase ion-exchange procedures commonly used to modify zeolite Y are impacted by the liquid water and its removal, even when fractional heating rates and inert conditions much less severe than standard practice are used for catalyst dehydration. X-ray diffraction, thermogravimetric, and spectroscopic analyses reveal that the majority of framework degradation occurs during the removal of a strongly bound water fraction in HY, which does not form when NH4Y is immersed in liquid water and which leads to reduced acidity in HY even when dehydration conditions much milder than those typically practiced are employed. Na+-exchanged HY prepared via room-temperature aqueous dissolution demonstrates that Brønsted acid sites are lost in excess of the theoretical maximum that is possible from sodium titration. The structural impact of low-temperature aqueous-phase ion-exchange methods complicates the interpretation of subsequent data and likely explains the wide variation in reported acid site concentrations and catalytic activity of HY zeolites with high-Al content.