Search

The recycled conductive agent (left) was able to be nitrogen doped by nitrogen-cooled plasma treatment to become an effective ORR/OER bifunctional catalyst (right). [Display omitted] • ORR/OER catalyst is prepared using discarded Li batteries. • Cold plasma treatment leads to a larger specific surface area. • Enhanced catalyst for ORR and OER. • Zinc-air batteries achieve 640 mAh/g capacity and 92 mW cm−2 power density. • Aqueous zinc-air batteries are capable of stable charge/discharge cycles of 100 h. Considerable amount of high-value transition metals components can be recycled in spent ternary lithium-ion batteries. In this study, we utilized the conductive agent carbon black, obtained from the leaching waste resulting from the chemical recovery of spent lithium-nickel-manganese-cobalt (NCM) oxide cathode materials. This process allows us to create valuable bifunctional catalysts for the oxygen reduction reaction and oxygen evolution reaction (ORR/OER), facilitated by a facile cold plasma activation method, as a part of lithium batteries circular economy. The activated conductive agent (RCA-30) exhibited an ORR half-wave potential of 0.74 V (vs. RHE) in 0.1 mol/L KOH solution, and an OER overpotential of 360 mV at 10 mA cm-2 in 1 mol/L KOH electrolyte, owing to nitrogen doping of carbon black and activation of surface metal oxides. The complete zinc-air batteries incorporating the activated catalysts at the cathode exhibited an open circuit potential of up to 1.48 V and sustained cycling for 100 h at a current density of 5 mA cm-2. Additionally, the activated catalysts contributed to a power density of 92 mW cm-2 and a full discharge capacity of 640 mAh/g. [ABSTRACT FROM AUTHOR]

This work focuses on the comparison of H2 evolution in the hydrolysis of boron-containing hydrides (NaBH4, NH3BH3, and (CH2NH2BH3)2) over the Co metal catalyst and the Co3O4-based catalysts. The Co3O4 catalysts were activated in the reaction medium, and a small amount of CuO was added to activate Co3O4 under the action of weaker reducers (NH3BH3, (CH2NH2BH3)2). The high activity of Co3O4 has been previously associated with its reduced states (nanosized CoBn). The performed DFT modeling shows that activating water on the metal-like surface requires overcoming a higher energy barrier compared to hydride activation. The novelty of this study lies in its focus on understanding the impact of the remaining cobalt oxide phase. The XRD, TPR H2, TEM, Raman, and ATR FTIR confirm the formation of oxygen vacancies in the Co3O4 structure in the reaction medium, which increases the amount of adsorbed water. The kinetic isotopic effect measurements in D2O, as well as DFT modeling, reveal differences in water activation between Co and Co3O4-based catalysts. It can be assumed that the oxide phase serves not only as a precursor and support for the reduced nanosized cobalt active component but also as a key catalyst component that improves water activation. [ABSTRACT FROM AUTHOR]

The effect of metal nitrates on the activation of anthracite combustion process has been studied. Fe(NO3)2 · 9H2O and Cu(NO3)2 · 3H2O were used as nitrates in an amount of 5 wt% applied to anthracite powder (fraction less than 0.1 mm) by incipient wetness impregnation. Using scanning electron microscopy and EDX mapping, it was found that using this method of applying the additive makes it possible to achieve high dispersion and uniform distribution in the fuel composition. The characteristics of oxidation, ignition, and combustion were studied using thermal analysis methods and high-speed video recording in the combustion chamber at a temperature of 800°C. It was found that the use of metal nitrates contributes to an increase in the reactivity of anthracite as evidenced by a decrease in the temperature of the intensive oxidation beginning (ΔTi) by 23–84°C and the ignition delay time (Δti) by 0.9–2.2 seconds. The greatest effect of changing the reactivity of anthracite was recorded in the case of using copper nitrate additive. The use of nitrates also contributed to the decrease in the resulting fuel underburning (from 3.5 to 0.4 wt%) and gas-phase CO compounds (by 31–53%). At the early stages, combustion process of modified samples was accompanied by periodic formation of micro-explosions, which led to the activation and development of the particle surface. [ABSTRACT FROM AUTHOR]

The activation procedures of metals and alloys, crucial for hydrogen absorption, pose a significant challenge in the large-scale application of metal hydrides. This study introduces, for the first time, the Pulsed Laser Activation (PLA) method for hydrogen storage alloys. We demonstrated that the hydrogen storage ability of an aged (exposed to air for 30 days) Ti 11 V 30 Nb 28 Cr 31 body-centered cubic alloy can be restored by scanning the sample with a nanosecond pulsed laser for only 3 min. X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS) analyses were conducted to investigate structural features that changed in the Ti 11 V 30 Nb 28 Cr 31 samples after ageing and after the PLA treatment. Surface remelting, the formation of oxide layers, and crack formation appear to be factors influencing the hydrogen storage ability of the Ti 11 V 30 Nb 28 Cr 31 alloy activated via PLA. While the mechanisms involved in the PLA are not clear yet, this procedure paves the way for the development of activation methods based on laser-metal interactions that can be easily applied to metals and alloys for hydrogen storage systems. • The novel Pulsed Laser Activation Method (PLA) is introduced. • PLA is effective to retore the hydrogen storage ability of alloys exposed to air. • The PLA method was tested in the Ti 11 V 30 Nb 28 Cr 31 alloy exposed to air for 30 days. • The changes on the alloy surface caused by the PLA method were investigated. [ABSTRACT FROM AUTHOR]

High-level ab-initio calculations show neutral tri-coordinate pyramidal boron centers P3B and As3B that can be used to activate H2O and NH3 molecule. The acidic center and the basic center of the pyramidal species are bonded, yet due to the spatial arrangement of the respective orbitals, they are forbidden to interact with each other. This bifunctional property is utilized to carry out the activation process of water and ammonia in a metal-free approach. [ABSTRACT FROM AUTHOR]

A number of Pt-Re gasoline reforming catalysts have been synthesized, differing from each other in chemical composition and preparation method. The synthesized catalysts exhibit fairly high activity under the studied conditions (T = 480-500 °C, V = 2.0 h-1, P = 8 atm and H2/feed = 5.5). [ABSTRACT FROM AUTHOR]

The improvement in the degradation efficiency of dimethoate was achieved through the activation of UV light and metal ions. The study found that Fe(VI) was effectively activated by Cu(II), Fe(III), and Fe(II), resulting in an improved removal rate of dimethoate in water, with the activation efficiency of Cu(II) > Fe(III) > Fe(II). Under UV irradiation, the synergistic activation effects of UV-Cu(II) and UV-Fe(III) were most pronounced and positively correlated with light intensity. The mineralization rate of dimethoate by UV-Fe(III)-Fe(VI) reached up to 37 %, significantly outperforming the Cu(II)-Fe(VI) system. The main active species in the Cu(II)-Fe(VI) and Fe(III)-Fe(VI) systems were Cu(III) and Fe(IV)/Fe(V), while those in the UV-Fe(III)-Fe(VI) were ·OH and ·O 2 - radicals, respectively. In the UV-metal ions activated Fe (VI) system, the main degradation mechanisms of dimethoate were hydrolysis, cleavage, oxidation, and recombination. The impacts of water quality parameters on degradation efficiency were also investigated, finding that Cl- had almost no effect, while SO 4 2- had a slight repression effect, and HCO 3 -, CO 3 2- and NO 2 - exhibited strong inhibitory effects. Finally, the promising application of the UV-metal ion-Fe(VI) system in actual water environments was proposed, achieving effective removal with minimal environmental risks. [Display omitted] • Fe(VI) can slightly degrade dimethoate, and metal ion activation intensifies this. • Different metal ions vary in activation ability: Cu(II) > Fe(III) > Fe(II). • UV enhances Cu(II) and Fe(III) activation of Fe(VI) for dimethoate degradation. • The introduction of UV light changes the active material. • The UV-Fe(III)-Fe(VI) system may lead to more complete degradation of dimethoate. [ABSTRACT FROM AUTHOR]

Polyaromatic hydrocarbons (PAHs) are the most persistent compounds that get contaminated in the soil and water. Nearly 16 PAHs was considered to be a very toxic according US protection Agency. Though its concentration level is low in the environments but the effects due to it, is enormous. Advanced Oxidation Process (AOP) is an emergent methodology towards treating such pollutants with low and high molecular weight of complex substances. In this study, sulfate radical (SO 4 ‾•) based AOP is emphasized for purging PAH from different sources. This review essentially concentrated on the mechanism of SO 4 ‾• for the remediation of pollutants from different sources and the effects caused due to these pollutants in the environment was reduced by this mechanism is revealed in this review. It also talks about the SO 4 ‾• precursors like Peroxymonosulfate (PMS) and Persulfate (PS) and their active participation in treating the different sources of toxic pollutants. Though PS and PMS is used for removing different contaminants, the degradation of PAH due to SO 4 ‾• was presented particularly. The hydroxyl radical ( • OH) mechanism-based methods are also emphasized in this review along with their limitations. In addition to that, different activation methods of PS and PMS were discussed which highlighted the performance of transition metals in activation. Also this review opened up about the degradation efficiency of contaminants, which was mostly higher than 90% where transition metals were used for activation. Especially, on usage of nanoparticles even 100% of degradation could be able to achieve was clearly showed in this literature study. This study mainly proposed the treatment of PAH present in the soil and water using SO 4 ‾• with different activation methodologies. Particularly, it emphasized about the importance of treating the PAH to overcome the risk associated with the environment and humans due to its contamination. [ABSTRACT FROM AUTHOR]

Seven advanced oxidation processes based on sulfate radical activation of persulfate are reviewed, including electrochemical activation, transition metal ion activation, thermal activation, and photoactivation, and the research progress of this technology at home and abroad. The reaction mechanism of the advanced oxidation process based on sulfate radicals is summarized, and the effects of temperature, initial pH, persulfate concentration and degrading agent concentration on the degradation effect of this technology are analyzed. Advanced oxidation processes based on sulfate radicals have promising applications, but the technology still have limitation. This paper also points out that in the future, it is necessary to increase the sewage purification experiments based on sulfate radicals in the real environment. To establish a theoretical system for selecting activation methods, types of oxidants, and determining the ratio of oxidants to pollutants. To develop low-cost and recontamination -free activation methods. These measures promote the development and application of this technology in the degradation of actual sewage. [ABSTRACT FROM AUTHOR]

Recently geopolymer technology possesses not only great efficiency in immobilizing heavy metal wastes but also produces valuable materials that can be applied in building sectors. The aim of this study is to examine the capability of geopolymers in the immobilization and entrapping of heavy metals bearing materials. The study will focus on the evaluation of optimum ratio of heavy metal that can affect and densify the produced composite. The studied mortar's binder was made from blast furnace slag, while the used fine aggregates were air-cooled slag < 1 mm. However, the used activator was 8% sodium hydroxide. The studied heavy metals' bearing materials were barium sulfate, lead phosphate, lead slag and electric arc furnace dust used as partial replacement of blast furnace slag. The physico-mechanical characterization of each set of samples was conducted using XRD, FTIR, SEM, compressive strength and bulk density. Results demonstrated that barium sulfate can be efficiently used up to 2%, lead phosphate up to 1%, lead slag up to 5% and electric arc furnace dust up to 10%. [ABSTRACT FROM AUTHOR]

[Display omitted] • The activation mechanism of sphalerite by impurities with d10 electron configuration is studied. • The relationship between d-s orbital hybridization and metal ion activated sphalerite is revealed. • The greater the polarizability, the better the activation of sphalerite by metal ions. The activation mechanism of metal ions with d10 inert electronic configurations on sphalerite (ZnS) were studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray fluorescence (XRF), and X-ray photoelectron spectroscopy (XPS), combined with density functional theory (DFT). Flotation experiments showed that the addition of activators increased sphalerite recovery by 50–70 %. The XPS results indicated that these inert cations with d10 electronic configurations formed stable metal sulfides (Cu 2 S, CuS, Ag 2 S, CdS, and HgS) on the sphalerite surface. The FTIR results demonstrated that the activated sphalerite enhanced the adsorption stability of butyl xanthate on the sphalerite surface. DFT studies found that metal ion introduction reduced surface relaxation and decreased the band gap on the sphalerite surface, both of which increased butyl xanthate adsorption. Finally, it was suggested in this study that the energy required for the d10 to d9s1 electron transition and the polarization could be used to predict the potential sphalerite activator. [ABSTRACT FROM AUTHOR]

Activation of metal nodes in metal–organic frameworks (MOFs) has been viewed as an essential step prior to their use for various potential applications. So far, a thermal method has been most commonly employed for the activation despite its negative influence on the structural integrity of MOFs. Meanwhile, DUT‐34 has been considered as an ideal platform for the above applications due to its open‐metal sites (OMSs) at the Cu node. However, the activation of DUT‐34 has not been successful because of its fragile characteristics. In this article, we report the coordination‐chemistry‐controlled activation, namely chemical route activation, using chloromethanes. By monitoring the coordination exchangeability of chloromethanes, we demonstrate that the chloromethanes can weakly coordinate at the OMSs. Further, we demonstrate that this coordination exchange is a safe activation method to retain the framework structure of DUT‐34, based on the observation that the DUT‐34 placed in TCM remained intact over 2 months. [ABSTRACT FROM AUTHOR]

The use of earth-abundant metal-catalysed organic transformations has increased significantly in recent years. Where low-oxidation-state catalysts are required, the in situ activation of metal(II/III) salts offers an operationally simple method to access these catalysts. Here we present the development of activation strategies from the use of reducing organometallic reagents to endogenous activation. Applications in alkene and alkyne hydrofunctionalisation reactions will be used to highlight the synthetic applications of the activation methods discussed. 1 Introduction 2 In situ Activation Using Organometallic Reagents 3 In situ Activation Using Nonorganometallic Reagents 4 'Activator-Free' Systems 5 Conclusions [ABSTRACT FROM AUTHOR]

The lignin-based carbon fibers were prepared by electrospinning followed by stabilization, carbonization, and activation (i.e., steam activation, one-step KOH activation, and metal activation). The effect of carbonization temperature on prepared carbon fibers (CFs) was investigated. As a result, 800 °C is the most suitable carbonization temperature because the prepared carbon fibers possess greater specific surface area and pore volume. With the help of various characterization methods, the structural characteristics of the activated carbon fibers (ACFs) prepared by the three activation methods and the adsorption performance of toluene were compared. It was observed that the activated carbon fibers prepared by KOH one-step activation method (ACFK) exhibited higher specific surface area (1147.16 m2/g) and greater toluene adsorption (463 mg/g). Particularly, abundant microporous structures and surface functional groups play a vital role in the adsorption process. Further, the adsorption performance of toluene onto ACFK was further investigated in a gas-phase dynamic adsorption system and the results showed that ACFK has great potential application in adsorption of volatile organic compounds. [ABSTRACT FROM AUTHOR]

Potential–pH diagrams for a chalcopyrite–xanthate–H2O and chalcopyrite–NaCN–H2O systems at 298 K were constructed to predict depressing components in the flotation of depressed chalcopyrite in cyanidation tailings using xanthate as a collector. Sodium hypochlorite, hydrogen peroxide, and copper sulfate were used as activators to reduce this depression effect, and the potential–pH diagram for the activator–H2O system was constructed to predict the thermodynamic activating ability.andwere dominant in the acidic-to-alkaline region. In alkaline solution, the generation potentials ofandwere lower than that ofCuX.Therefore, they are the main depressing components that influence the flotation of chalcopyrite in cyanidation tailings. In the alkaline region, the oxidative potentials of sodium hypochlorite, hydrogen peroxide, and copper sulfate were significantly higher than that of CN–, so CN– was easily oxidized. This resulted in activation through the loss of hydrophilicity. [ABSTRACT FROM AUTHOR]

Germanium with its high carrier mobility is currently being investigated as an alternative material to silicon for advanced MOS devices. We have reviewed the literature on n-type and p-type doping of germanium and established a baseline calibration for technology process simulation. Fundamental parameters for germanium point defects have been selected and extended defect evolution has been calibrated. Models and parameters for accurate simulation of ion implantation, diffusion, and activation of the most common dopants (phosphorus and arsenic for n-type, boron for p-type) have been defined. We discuss the current accuracy and limitations of the process calibration and specify missing experimental data needed for enhancing and broaden the simulation capabilities for germanium processing. [ABSTRACT FROM AUTHOR]

• Fe3+, Mg2+, and Ca2+ exhibited strong activation ability for the spodumene flotation. • The activation ability of Ca2+ and Mg2+ to spodumene is stronger than that of Fe3+. • The metal ions provided more active sites for the adsorption of NaOL. • The colloidal complexes of metal ions and NaOL strengthened the spodumene flotation. The existence of metal ions is inevitable in the spodumene ore beneficiation and the study of their interaction mechanism with spodumene is of great significance for the spodumene flotation. In this work, the effect of Fe3+, Mg2+, and Ca2+ on the flotation behavior of spodumene with NaOL was investigated through micro-flotation experiments. The flotation results showed that Fe3+, Mg2+, and Ca2+ exhibited strong activation ability at pH 6.5, 10.9, and 12.1, respectively, and the activation ability of Mg2+ and Ca2+ toward spodumene was superior compared to that of Fe3+. The activation mechanism of metal ions was explored by the Visual MINTEQ model, in-situ attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The results of species distribution calculated by the Visual MINTEQ model and in situ ATR-FTIR demonstrated that NaOL adsorbed more strongly onto spodumene in the presence of Mg2+and Ca2+ compared with that of Fe3+, resulting in better activation of Mg2+and Ca2+. In addition, XPS and ToF-SIMS analyses revealed that the activation of spodumene by metal ions works in two ways. It not only provides more active sites for the adsorption of NaOL, but also interacts with NaOL to form the colloidal complexes and then adsorbed on the spodumene surface. [ABSTRACT FROM AUTHOR]

Keywords: activation; glycans; glycosylation; thioglycosides EN activation glycans glycosylation thioglycosides 1 1 1 03/11/22 20220307 NES 220307 Methods for transition metal mediated activation of thioglycosides have been classified and discussed. Frontispiece: Transition-Metal-Mediated Glycosylation with Thioglycosides Activation, glycans, glycosylation, thioglycosides. [Extracted from the article]

Abstract: A pyrolysis product derived from Sasol-Lurgi gasifier pitch was activated using different proportions of KOH. The increase of the amount of KOH used for activation caused the activation degree of the carbons to increase very significantly. The activated carbons obtained using lower amounts of KOH were mainly microporous, while the amount of mesopores developed in the samples progressively increased for the carbons activated with higher proportions of KOH. The gravimetric specific capacitance of samples obtained with (2:1), (3:1) and (5:1) KOH to carbon ratio were rather similar at low current densities (∼400F/g at low current densities), despite the significant differences observed in their textural characteristics. Supercapacitors built with the activated carbons obtained with (2:1) and (3:1) KOH to carbon ratio yielded the highest volumetric capacitance (higher than 200F/cm3 at low current densities), while the most activated sample yielded the lowest values, due to the significant reduction in density caused by activation. The high values of capacitance observed result from the combination of two mechanisms of energy storage: double layer formation and pseudocapacitance. [Copyright &y& Elsevier]