Simple Ion Research Articles

Facilely Direct Construction, White-Light Emission, and Color-Adjustable Luminescence of LaF3 :Pr3+ @SiO2 Yolk-Shell Nanospheres with Moisture Resistance.

Poor water stability and single luminous color are the major drawbacks of the most phosphors reported. Therefore, it is important to realize multicolor luminescence in a phosphor with single host and single activator as well as moisture resistance. LaF3 :Pr3+ @SiO2 yolk-shell nanospheres are facilely obtained by a designing new technology of a simple and cost-effective electrospray ionization combined with a dicrucible fluorating technique without using protective gas. In addition, tunable photoluminescence, especially white-light emission, is successfully obtained in LaF3 :Pr3+ @SiO2 yolk-shell nanospheres by adjusting Pr3+ ion concentrations, and the luminescence mechanism of Pr3+ ion is advanced. Compared with the counterpart LaF3 :Pr3+ nanospheres, the water stability of LaF3 :Pr3+ @SiO2 yolk-shell nanospheres is improved by 15% after immersion in water for 72h, and the fluorescence intensity can be maintained at 86% of the initial intensity. Furthermore, by treating the yolk-shell nanospheres with hydrofluoric acid, it is not only demonstrated that the shell-layer is SiO2 but also core-LaF3 :Pr3+ nanospheres are obtained. Particularly, only fluorination procedure among the halogenation can produce such special yolk-shell nanospheres, the formation mechanism of yolk-shell nanospheres is proposed detailedly based on the sound experiments and a corresponding new technology is built. These findings broaden practical applications of LaF3 :Pr3+ @SiO2 yolk-shell nanospheres.

Implications of Cation-Dependent Proton Affinity on Electrocatalytic Nitrate Reduction

Perturbation of the nitrogen cycle via Haber-Bosch nitrogen fixation and concomitant fertilizer amendment has manifested in alarmingly increased groundwater nitrate concentrations, with global human-health and ecological ramifications. Correspondingly, the denitrification of drinking water resources represents a growing area of energy consumption, though is still outpaced by the carbon-intensive Haber-Bosch process. Electrocatalytic nitrate reduction therefore offers a competitive and distributable green alternative to traditional ammonia production approaches, using renewably-sourced electrons and protons sourced from water as reducing agents without the need for added chemicals or elevated temperatures and pressures.While considerable progress has been made in understanding the effects of electrocatalyst material parameters on nitrate reduction activity and ammonium selectivity, these studies are conducted in well-controlled and highly purified electrolytes that lack the complexity typical of expected nitrate-rich waste source streams. Recent literature on other electrocatalytic hydrogenation reactions (hydrogen evolution and carbon dioxide reduction reactions) has identified cation-dependent activity and selectivity, indicating the significance of these nominally simple ions in facilitating proton abstraction from water—of particular importance in the proton-hungry conversion of nitrate to ammonium (10 H+ per nitrate converted). Here, we investigate cation-dependent (Li+, Na+, K+) nitrate reduction activity and selectivity in (phosphate) buffered neutral electrolytes across a series of transition metals known to exhibit varying ammonium selectivities (Ag, Cu, Co). We frame our discussion of observed cation-dependent activity and selectivity within empirical literature on cation hydration free energy to understand the role of cations in mediating proton transfer during electrocatalytic hydrogenation reactions.

Determination of mass-dependent chromium isotopic compositions in geological samples by double spike-total evaporation-thermal ionization mass spectrometry (DS-TE-TIMS)

BackgroundChromium isotopes have been used to trace geochemical and cosmochemical processes in the past. However, the presence of multivalent Cr species has made it difficult to isolate Cr from geological samples, particularly for samples with a low Cr mass fraction. ResultsHere, a simple three-step ion exchange chromatography procedure is presented to separate Cr from various sample matrices, ranging from ultramafic to felsic rocks. Throughout each of the column chromatography step, 1 mL of cation exchange resin AG50W-X8 (200–400 mesh) was used as the stationary phase and oxalic acid as a chelating agent, was used in addition to the inorganic acids. This method yielded high recoveries of Cr [93 ± 8% (2SD, N = 7)] regardless of the lithology. The total procedural blank of Cr was <0.5 ng. We also developed a double spike-total evaporation-thermal ionization mass spectrometry (DS-TE-TIMS) technique that significantly reduced sample consumption to ∼20 ng of Cr per each measurement of mass-dependent 53Cr/52Cr. SignificanceThis study achieved a 2SD external precision of 0.02‰ for the analysis of NIST NBS3112a and of 0.01–0.07‰ for the geological samples. This study enabled high-precision Cr isotope analysis in geological samples with various matrix and Cr compositions using relatively small sample volumes.

Fabrication of a GUMBOS-based ratiometric organo nanosensor for selective and sensitive detection of perchlorate ions that works in 100% water

This work intends to develop sensitive and easily applicable ionic liquids (ILs)-based fluorimetric sensors for detecting the explosive perchlorate (ClO4-) anions in the presence of other hazards and interferents. We have designed and developed an IL-compromising pyrene butyrate anion-based fluorophoric group of uniform materials based on organic salts (GUMBOS), PBIL, from sodium pyrene butyrate and trihexyltetradecylphosphonium chloride (P66614Cl) by simple ion exchange mechanism. Using reprecipitation methods, pyrene-based water-suspended nano-GUMBOS, nPBIL, has been fabricated and characterized by numerous analytical methods. The fabricated nano-GUMBOS display bright cyan color photoluminescence due to the excimer-like emission confirmed from the color chromaticity diagram. Interestingly, due to the addition of ClO4- ions, there is a blue shift in the UV–visible absorption spectrum of the nPBIL solution with a simultaneous decrease in Mie-scattering. Consequently, there is a continuous decrease in the excimer-like emission of nPBIL with the synchronized increase in monomeric emission. We can conclude from both UV–visible absorption and emission spectra that the ClO4- ion displaces the anionic pyrene butyrate moiety of our nPBIL due to its high polarizability. The limit of detection (LOD) of the as-fabricated sensor is estimated to be 7.17 nM which is very much lower than the US Environmental Protection Agency (USEPA) predicted permeable level of perchlorate in drinking water (15 μgL−1). An efficient test kit has been fabricated and demonstrated for on-site detection of ClO4- ions in remote areas. This ion exchange-mediated substance release from such nano-GUMBOS systems is a distinctive and innovative way to design and develop efficient sensors for precisely detecting and quantifying ClO4- ions.

A simple and robust LC-ESI single quadrupole MS-based method to analyze polyphenols in plant extracts using deep eutectic solvents

Currently, the interest in polyphenols is increasing due to their significant properties in health. Polyphenols exist in a range of natural products, however their extraction as well as their characterization are important issues as they are mainly present in complex matrices. Therefore, sensitive and selective analytical methods based on liquid chromatography coupled to tandem mass spectrometry are essential. Nevertheless, access to such high-resolution techniques is quite rare. Thus, in this work we present a simple, selective and robust method based on a single-quadrupole (Q) MS technique) for the analysis of a wide range of polyphenols such as flavonoids, phenolic acids and anthocyanins.Specifically, we present:•A simple liquid chromatography electro-spray ionization (LC-ESI) single-quadrupole mass selective (MS) method for the analysis of 18 different polyphenols.•Application of the method to three plant-based extracts that are derived after green extraction methods.

Ionic liquids-based organo nano-fluorosensor for fast and selective detection of sarin gas surrogate, diethylchlorophosphate

This work intends to develop a sensitive and easily applicable ionic liquid (IL) based fluorimetric sensor for detecting sarin surrogate, diethylchlorophosphate (DCP) in solution and gas phases, respectively. We have designed and synthesized a pyrene butyrate anion-based IL (PBIL) from the sodium salt of pyrene butyrate and trihexyltetradecylphosphonium chloride (P66614Cl) by a simple ion exchange mechanism. By utilizing reprecipitation methods, PBIL-based nanoparticles, nPBIL, has been fabricated. Various conventional analytical techniques have confirmed the formations of PBIL and nPBIL. The as-prepared nPBIL shows a structured emission band from 300 to 420 nm along with an excimer-like emission range from 420 nm to 600 nm and displays bright cyan color photoluminescence because of the stacking of pyrene moieties in a nanocrystalline fashion. Interestingly, due to the introduction of DCP in the water-suspended nPBIL, there is a slight (6 nm) blue shift in the UV–visible absorption spectra with an immediate reduction in Mie-scattering. Simultaneously, there is a gradual decrease in excimer-like emission with a synchronized increase in monomeric emission with the steady introduction of DCP in the water-suspended solution of nPBIL due to the formation of a phosphorylated product. The limit of detection (LOD) utilizing our as-fabricated organo nanosensor, nPBIL, towards the detection of DCP is estimated to be 7.32 µM and found to be superior to many chemosensors available in the literature. An nPBIL-stained test kit experiment has also been demonstrated as a carriable and visible photonic device for the on-site detection of DCP within the assembly of other analogous harmful analytes. Also, a dip-stick analysis has been performed for selective recognization of DCP vapor. The effectiveness of nPBIL in identifying and quantifying DCP demonstrated its potential for usage as a photonic device for practical sample investigation.

Fabrication of a re-useable ionic liquid-based colorimetric organo nanosensor for detection of nerve agents’ stimulants

Nerve agents are highly poisonous organophosphorus chemicals, and the possibility of being used in terrorist attacks seriously threatens public safety. Thus, developing quick and straightforward detection techniques for these dangerous substances is paramount for the scientific communities. In this contribution, we have fabricated a sensitive and easily applicable ionic liquids (ILs) based colorimetric sensor for detecting various nerve agents' stimulants in solution and gas phases, respectively, based on methyl orange (MO)-based IL ([P66614]+[MO]-) derived from MO dye and trihexyltetradecylphosphonium chloride (P66614Cl) by a simple ion exchange mechanism. The developed [P66614]+[MO]- and water-suspended [P66614]+[MO]- nanoparticles are found to be very much sensitive to detecting various nerve agents' stimulants having detection limits in the μM range in any medium and could be identified based on the response times which is found to be superior to many chemosensors available in the literature. The naked eye observed a distinct color change from yellow to fuchsia in the presence of nerve agents' stimulants, which shows better sensitivity than the free organic indicator. Furthermore, a facile test strip with [P66614]+[MO]- and water-suspended [P66614]+[MO]- NPs has been fabricated that can achieve visual detection of various nerve agents' stimulants within the stockpiles of other analogous harmful analytes. Also, a dip-stick experiment has been performed to detect harmful toxic analytes vapor. The effectiveness of [P66614]+[MO]- and water-suspended [P66614]+[MO]- NPs in identifying and quantifying various nerve agents’ stimulants demonstrated its potential for usage as a signal tool for real sample analysis.

Does the Sign of Charge Affect the Surface Affinity of Simple Ions?

The role the charge sign of simple ions plays in determining their surface affinity in aqueous solutions is investigated by computer simulation methods. For this purpose, the free surface of aqueous solutions of fictitious salts is simulated at finite concentration both with nonpolarizable point-charge and polarizable Gaussian-charge potential models. The salts consist of monovalent cations and anions that are, apart from the sign of their charge, identical to each other. In particular, we consider the small Na+ and the large I- ions together with their charge-inverted counterparts. In an attempt to avoid the interference even between the behavior of cations and anions, we also simulate systems containing only one of the above ions, and determine the free energy profile of these ions across the liquid-vapor interface of water at infinite dilution by potential of mean force (PMF) calculations. The obtained results reveal that, in the case of small ions, the anion is hydrated considerably stronger than the cation due to the close approach of water H atoms, bearing a positive fractional charge. As a consequence, the surface affinity of a small anion is even smaller than that of its cationic counterpart. However, considering that small ions are effectively repelled from the water surface, the importance of this difference is negligible. Further, a change in the hydration energy trends of the two oppositely charged ions is observed with their increasing size. This change is largely attributed to the fact that, with increasing ion size, the factor of 2 in the magnitude of the fractional charge of the closely approaching water atoms (i.e., O around cations and H around anions) outweighs the closer approach of the H than the O atom in the hydration energy. Thus, for large ions, being already surface active themselves, the surface affinity of the anion is larger than that of its positively charged counterpart. Further, such a difference is seen even in the case when the sign of the surface potential favors the adsorption of cations.

PENGARUH EFEKTIVITAS PROGRAM KARTU TANI TERHADAP KESEJAHTERAAN MASYARAKAT DI DESA BULO KECAMATAN PANCA RIJANG KABUPATEN SIDENRENG RAPPANG

The farmer card is a card specifically designed to allocate subsidized fertilizers to farmers. This study aims to determine the level of community welfare towards the farmer card program in Bolu Village, Panca Rinjang District, Sidenreng Rappang Regency. The benefit of this research is that it can provide input, and information, and become material for policymakers related to organizational culture in the performance of village apparatus so that they can optimize good relations and become a consideration for further strategic steps. This research uses quantitative methods, the population in this study is the people of Bulo Village, Panca Rijang District, Sidenreng Rappang Regency who are registered as recipients of the Farmer Card Program as many as 600 farmers who are members of 28 farmer groups. Data analysis will be carried out using the SPSS program. The research data were analyzed using statistical tools consisting of measurement scale instruments, data quality tests, simple linear regression, ion and hypothesis testing. Hypothesis Ha: The effectiveness of the program has a significant effect on the welfare of the community in Bulo Village, Panca Rijang Distriand ct, Sidenreng Rappang Regency. Tcotable blof value or 10.087 1.66320 then Ha is accepted, meaning it is significant. So, Effectiveness influences/significantly affects Community Welfare in Bulo Village, Panca Rijang District, Sidenreng Rappang Regency. The percentage value of the indicator for the level of community welfare for the Farmer Program in Bulo Village, Panca Rijang District, Sidenreng Rappang Regency is 58% which is in the unfavorable category.

#5565 USEFULNESS OF URINARY BIOCHEMISTRY IN THE FOLLOW-UP OF PATIENTS WITH CHRONIC KIDNEY DISEASE STAGES 3B-5NOD

Abstract Background and Aims Ion and protein determinations in a simple urine sample are simple and inexpensive laboratory tests that reflect well ion balance and proteinuria. However, they are underused. Evidence of their usefulness in estimating 24-hour urine biochemistry in patients with chronic kidney disease (CKD) would allow widespread use of these tests and would help to optimize therapies. It would also avoid 24-hour urine collections. To evaluate In CKD stages G3b-5noD the accuracy of equations that estimate, through simple urine sampling, creatinine, protein, and ions in 24-hour urines. Method Retrospective observational study in incident adult patients with CKD G3b-5noD from the nephrology outpatient clinic in a Madrid university hospital, with a follow-up of at least two years and with at least one simultaneous determination of biochemistry in a simple urine sample and in 24-hour urine. The 24-hour urine analyses were restricted to those that were estimated to be well collected because urinary creatinine was between 15–25 mg/kg in men and 10–20 mg/kg in women. Correlation, bias (mean differences between estimated and measured analyte), accuracy (percentage of samples estimated at 15–30 or 50% of the measured value - P15, P30, P50) and agreement by the Bland-Altman method were analyzed. CKD progression was defined by the mean annual and percentage decrease in eGFR and the renal event at follow-up as loss of more than 40% of eGFR or entry into renal replacement therapy or conservative-palliative renal treatment. Kawasaki, Tanaka and CKD-epi (Table 1) equations were used. Results The analyzed cohort was made up of 300 patients with a median follow-up of 72 (25) months. Mean eGFR was 32.8 (9.2) ml/min/1.73m2 and mean protein/creatinine ratio was 1,180 (1,740) mg/g. During follow-up 30.7% started renal replacement therapy or conservative and palliative treatment. Twenty-one patients (7%) died. The estimation of 24-hour urine creatinine by CKD-EPI equation showed excellent correlation and accuracy with measured urinary creatinine (r = 0.887; P30: 96.1% in 464 urines). Accuracy was maintained regardless of age and CKD stage. Formulas that, using single urine samples, estimate 24-hour urine elimination of Na and K correlated well with 24-hour urine measurements, but with high dispersion, especially with Na. For Na, the Tanaka and CKD-EPI formulas had the highest performance (r = 0.540; 0.532; P30: 52.6; 54.5%; bias: -14.4; -16.1 mmol, Tanaka and CKD-EPI respectively for 464 urines). These values make them useful for population studies but not for individualized analysis. For K, the Kawasaki and CKD-EPI formulas were the most suitable (r = 0.712; 0.612; P30 = 74.6; 72.4%; bias: 4.2; 5.5 mmol; Kawasaki and CKD-EPI respectively for 464 urines). These results make them useful for both population-based studies and individualized analyses. Patients with Nao &amp;lt; 87 mmol/day (salt-poor diet) estimated by CKD-EPI, Kawasaki or Tanaka and/or Na/K ratio &amp;lt; 2 directly measured had less eGFR loss at follow-up and fewer renal events. Urinary K elimination measured or estimated did not influence renal prognosis. Proteinuria measured in 24-hour urine correlated much better with proteinuria estimated by CKD-EPI in a single urine sample than with the protein/creatinine ratio (r: 0.900 vs. 0.801; mean bias: 92.2 vs. 486 mg; P30: 72.0 vs. 42.7%; CKD-EPI vs. Proto/Cro in 464 24-hour urine samples). Conclusion Urinary biochemistry in a single urine sample in patients with advanced CKD (stages G3b-5noD) is a useful tool for estimating 24-hour urine biochemistry and to identify scenarios of increased progression of renal disease.

Discrimination of the Enantiotopic Faces of Structurally Unbiased Carbenium Ions Employing a Cyclohexadiene-Based Chiral Hydride Source.

An enantioselective reduction of simple carbenium ions with cyclohexadienes containing a hydridic C-H bond at an asymmetrically substituted carbon atom is disclosed. The net reaction is a transfer hydrogenation of alkenes (styrenes) only employing chiral cyclohexadienes as dihydrogen surrogates. The trityl cation is used to initiate a Brønsted acid-promoted process, in which a delicate intermolecular capture of a carbenium-ion intermediate by the aforementioned chiral hydride source is enantioselectivity determining. Exclusively non-covalent interactions are rendering one of the transition states energetically more favored, giving the reduction products in good enantiomeric ratios. The computed reaction mechanism supports the present findings as well as previous results obtained from studies on other transfer-hydrogenation methods involving the cyclohexadiene platform.

Unterscheidung der enantiotopen Seiten von strukturell unvoreingenommenen Carbeniumionen unter Verwendung einer cyclohexadienbasierten, chiralen Hydridquelle

AbstractEs wird eine enantioselektive Reduktion von einfachen Carbeniumionen mit Cyclohexadienen, die eine hydridische C‐H‐Bindung an einem asymmetrisch substituierten Kohlenstoffatom tragen, vorgestellt. Die grundlegende Reaktion ist eine Transferhydrierung von Alkenen (Styrolen), bei der ausschließlich chirale Cyclohexadiene als Diwasserstoffsurrogate Anwendung finden. Das Tritylkation wird als Initiator dieses Brønsted‐Säure‐katalysierten Verfahrens eingesetzt, bei dem ein schwieriges intermolekulares Abfangen einer Carbeniumionenzwischenstufe durch die bereits erwähnte Hydridquelle enantioselektivitätsbestimmend ist. Lediglich nichtkovalente Wechselwirkungen begünstigen einen der Übergangszustände energetisch, was zu guten Enantiomerenverhältnissen der Hydrierungsprodukte führt. Der berechnete Reaktionsmechanismus sowie frühere Erkenntnisse aus Studien zu anderen Transferhydrierungsmethoden auf der Grundlage der Cyclohexadienplattform stützen die vorliegenden Ergebnisse.

The magnetic field design of a solenoid for the cold-cathode Penning ion source of a miniature neutron tube

A high-yield and beam-stable neutron tube can be applied in many fields. It is of great significance to the optimal external magnetic field intensity of the cold-cathode Penning ion source (PIS) and precisely controls the movement of deuterium (D), tritium (T) ions and electrons in the source of the neutron tubes. A cold-cathode PIS is designed based on the solenoidal magnetic field to obtain better uniformity of the magnetic field and higher yield of the neutron tube. The degree of magnetic field uniformity among the magnetic block, double magnetic rings and solenoidal ion sources is compared using finite element simulation methods. Using drift diffusion approximation and a magnetic field coupling method, the plasma distribution of hydrogen and the relationship between plasma density and magnetic field intensity at 0.06 Pa pressure and a solenoid magnetic field are obtained. The results show that the solenoidal ion source has the most uniform magnetic field distribution. The optimum magnetic field strength of about 0.1 T is obtained in the ion source at an excitation voltage of 1 V. The maximum average number density of monatomic hydrogen ions (H+) is 1 × 108 m−3, and an ion-beam current of about 14.51 μA is formed under the −5000 V extraction field. The study of the solenoidal magnetic field contributes to the understanding of the particle dynamics within the PIS and provides a reference for the further improvement of the source performance of the neutron tube in the future.

Photoluminescent pyrene-based ionic liquid derived ratiometric organo nanosensor for rapid and selective detection of picric acid

Due to the rising menace of illicit actions and pollution aroused by explosive nitroaromatic compounds (NACs), the growth of an adept sensor for detecting these NACs is highly essential. Herein, in this communication, a photoluminescent IL-assimilated group of uniform materials based on organic salt (GUMBOS) and nano-GUMBOS has been fabricated by integrating pyrene butyrate with a quaternary phosphonium IL (PbIL) via a simple ion exchange process. Neat PbIL shows a bright cyan color photoluminescence under a 365 nm UV lamp irradiation and is employed as photoluminescence security ink and picric acid (PA) detection among the tested NACs. By simple reprecipitation method, we have developed water-suspended crystalline pyrene assimilated nanoparticles, nPbIL, characterized by various analytical techniques. The PbIL-derived water-suspended nanomaterials, nPbIL, display a robust cyan color excimer-like emission, which turns blue (monomeric) due to adding PA over the other related NACs. This ratiometric cyan to blue photoluminesce change is due to the displacement of the anionic pyrene moiety of the nPbIL by the picrate anion. The fabricated organo nanosensor is enormously discerning and responsive towards PA with a detection limit of 0.77 nM and is found to be superior to many available in the literature. Additionally, a fluorogenic paper strip-based test kit experiment has been demonstrated to detect and quantify PA selectively in aqueous solvents amongst the other tested NACs. The present contribution evokes a novel approach to developing different IL-based chemosensors for detecting and quantifying various target analytes.

Highly Selective Photocatalytic Conversion of 5‐Hydroxymethyl‐2‐furfural to 2,5‐Diformylfuran over Gold Ion Exchanged Cadmium Sulfide Nanowire

Abstract5‐Hydroxymethyl furfural (HMF) obtained from biomass can be converted to 2,5‐diformylfuran (DFF), a valuable chemical intermediate. However, the typical HMF oxidation process requires energy consumption such as high temperature and oxygen pressure. Herein, Au2S decorated CdS nanowires (denoted as Au2S@CdS NWs) are fabricated by a simple ion exchange method and applied as a heterostructure photocatalyst system for HMF oxidation under mild conditions. Under visible light irradiation, the photocatalytic performance of Au2S@CdS NWs is significantly enhanced compared with pristine CdS NWs, in which Au2S (0.25%)@CdS NWs achieve the high DFF yield (≈95%) for 4 h reaction time. This result means that the heterogeneous interface formed between CdS NWs and Au2S promotes the separation efficiency of photogenerated charges, which leads to high catalytic activity. Moreover, Au2S (0.25%)@CdS NWs work well for HMF conversion to DFF under anaerobic and aerobic conditions. Control experiments and characterization are conducted to investigate each reaction mechanism. Consequently, it is found that the photogenerated hole directly oxidizes HMF to DFF under anaerobic conditions and the1O2produced from oxygen is the active species for HMF conversion to DFF under aerobic conditions.

Understanding the mechanism of saturated and mono-/tri-lacunary Keggin SiWx doped in Bi2WO6 and BiOBr for efficient photocatalytic CO2 reduction

Different from the doping of common simple ions, polyoxometalates (POMs) with the ability to regulate electron transfer as a large dopant and their doping mechanism is rarely studied. In this work, saturated and mono-/tri-lacunary Keggin SiWx (x = 9, 11, 12) have been successfully doped in Bi2WO6 and BiOBr through a two-step hydrothermal method, respectively, in which SiWx respectively replaced WO42− of Bi2WO6 and Br− of BiOBr, and are denoted as SiWx-Bi2WO6 and SiWx-BiOBr. As a shallow electron trap, SiWx inhibits photoinduced carrier recombination of Bi2WO6 and BiOBr. Besides, SiWx-Bi2WO6 and SiWx-BiOBr behave differently in photocatalytic CO2 reduction, which the CO yields of SiW9-Bi2WO6, SiW11-Bi2WO6 and SiW12-Bi2WO6 are 1.5, 3.3 and 6.2 times higher than Bi2WO6, while the CO yields of SiW9-BiOBr, SiW11-BiOBr and SiW12-BiOBr are 1.6, 2 and 2.6 times that of BiOBr. The corresponding reasons for the different performances can be attributed to the different hydrophobicity of the materials, reduction of the Bi2WO6 and BiOBr nanosheet stacking thickness and inhibition of carrier recombination. The deep insights into the influences of saturated and lacunary POMs on photocatalytic performances provide more ideas for the rational design of photocatalytic materials for CO2 reduction to high-valuable products.

A simple ion chromatography-mass spectrometry method for amino acid analysis in beer.

The amino acid footprint of different beer samples was analyzed using ion chromatography coupled with electrospray ionization mass spectrometry. A tailor-made polymer-based cation-exchange resin was operated with a mass spectrometry-compatible eluent under isocratic conditions on a standard high-performance liquid chromatography system coupled to a single quadrupole mass spectrometer using formic acid as a volatile eluent ion source. The partially separated peaks of the isomeric pair isoleucine/leucine were processed according to their area response ratio using vertical peak splitting or Gaussian fit. Additionally, the chromatographic resolution of the isomers was optimized with an adjusted, solely aqueous mobile phase from 0.85 to 2.92. Ion suppression in the electrospray ion source was investigated for the derivatization-free method and found to be insignificant (recovery value 100±15%) for 15 out of the 20 analytes. Quantitative results for various beer and mixed-beer beverages were found to be in high agreement with existing methods. Simultaneous photometric detection demonstrated the method's ability to successfully remove most of the interfering matrix compounds.

Prebiotic Synthesis of Aspartate Using Life's Metabolism as a Guide.

A protometabolic approach to the origins of life assumes that the conserved biochemistry of metabolism has direct continuity with prebiotic chemistry. One of the most important amino acids in modern biology is aspartic acid, serving as a nodal metabolite for the synthesis of many other essential biomolecules. Aspartate's prebiotic synthesis is complicated by the instability of its precursor, oxaloacetate. In this paper, we show that the use of the biologically relevant cofactor pyridoxamine, supported by metal ion catalysis, is sufficiently fast to offset oxaloacetate's degradation. Cu2+-catalysed transamination of oxaloacetate by pyridoxamine achieves around a 5% yield within 1 h, and can operate across a broad range of pH, temperature, and pressure. In addition, the synthesis of the downstream product β-alanine may also take place in the same reaction system at very low yields, directly mimicking an archaeal synthesis route. Amino group transfer supported by pyridoxal is shown to take place from aspartate to alanine, but the reverse reaction (alanine to aspartate) shows a poor yield. Overall, our results show that the nodal metabolite aspartate and related amino acids can indeed be synthesised via protometabolic pathways that foreshadow modern metabolism in the presence of the simple cofactor pyridoxamine and metal ions.

Phase interface manipulation by adjusting atomic ordering in metal-organic framework to facilitate microwave absorption

Metal-organic frames (MOFs) have been a suitable template for high-performance microwave absorbing materials. However, there has been a lack of effective solutions for the agglomeration and inadequate graphitization transformation of metal nanoparticles after annealing of MOFs. In this work, a simple and safe metal ion exchange method for the experimental process is proposed to etch the surface of Fe MOF (MIL-88) template using nickel metal salts, and the subsequent heat treatment to synthesize Fe-Ni/C nanorods. These fine and uniform metal particles and carefully designed phase engineering have excellent electromagnetic attenuation and good impedance matching. In particular, suitable defects and rich heterogeneous interfaces cause polarization loss to increase, and more obviously, hysteresis loss and natural resonance increase magnetic loss. The experimental results show that the materials have good broadband absorption (6.13 GHz) and high-efficiency loss (−35 dB) microwave absorbing (MA) performance. This work provides a generalized phase interface engineering approach for polymetallic nanorods and provides a useful reference for microwave absorbing materials.

Electrochemical-Shock Synthesis of Nanoparticles from Sub-femtoliter Nanodroplets

ConspectusNanoparticles have witnessed immense development in the past several decades due to their intriguing physicochemical properties. The modern chemist is interested not only in methods of synthesizing nanoparticles with tunable properties but also in the chemistry that nanoparticles can drive. While several methods exist to synthesize nanoparticles, it is often advantageous to put nanoparticles on a variety of conductive substrates for multiple applications (such as energy storage and conversion). Despite enjoying over 200 years of development, electrodeposition of nanoparticles suffers from a lack of control over nanoparticle size and morphology. There have been heroic efforts to address these issues over time. With an understanding that structure-function studies are imperative to understand the chemistry of nanoparticles, new methods are necessary to electrodeposit a variety of nanoparticles with control over macromorphology and also microstructure.This Account details our group's efforts in overcoming challenges of classical nanoparticle electrodeposition by electrodepositing nanoparticles from water nanodroplets. When a nanodroplet full of metal salt precursor is incident on the electrode biased sufficiently negative to drive electroplating, nanoparticles form at a fast rate (on the order of microseconds to milliseconds). We start with the general nuts-and-bolts of the experiment (nanodroplet formation and methods for electrodeposition). The deposition of new nanomaterials often requires one to develop new methods of measurement, and we detail new measurement tools for quantifying nanoparticle porosity and nanopore tortuosity within single nanoparticles. We achieve nanopore characterization by using Focused Ion Beam milling and Scanning Electron Microscopy. Owing to the small size of the nanodroplets and fast mass transfer (the contents of a femtoliter droplet can be electrolyzed in only a few milliseconds), the use of nanodroplets also allows the electrodeposition of high entropy alloy nanoparticles at room temperature.We detail how a deep understanding of ion transfer mechanisms can be used to expand the library of possible metals that can be deposited. Furthermore, simple ion changes in the dispersed droplet phase can decrease the cost per experiment by orders of magnitude. Finally, electrodeposition in aqueous nanodroplets can also be combined with stochastic electrochemistry for a variety of interesting studies. We detail the quantification of the growth kinetics of single nanoparticles in single aqueous nanodroplets. Nanodroplets can also be used as tiny reactors to trap only a few molecules of a metal salt precursor. Upon reduction to the zerovalent metal, electrocatalysis at very small metal clusters can be probed and evaluated with time using steady-state electrochemical measurements. Overall, this burgeoning synthetic tool is providing unexpected avenues of tunability of metal nanoparticles on conductive substrates.