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[Display omitted] Development of high energy density lithium-metal batteries (LMBs) is markedly hindered by the interfacial instability on lithium-metal anode side. Solid-electrolyte interphase (SEI) is a fundamental factor to regulate dendrite growth and enhance the stability of lithium-metal anodes. Here, trithiocyanuric acid, a triazine derivative with sulfhydryl groups, is used as an efficient promoter to favor the construction of a robust artificial SEI layer on the lithium metal surface, which greatly benefits the stability and efficiency of LMBs. With the assistance of trithiocyanuric acid facilely introduced on the Li surface via a one-step solution route, a highly uniform artificial SEI layer rich in Li 2 S and Li 3 N is formed, which efficiently facilitates uniform lithium deposition and suppresses lithium dendrite growth. Remarkably, the Li|Li cell displays stable lithium plating/stripping cycling over 800 h at 0.5 mA cm−2, 1 mAh cm−2, and the Li|LFP cells exhibit prolonged lifespan over 700 cycles at 3 C and superior rate performance from 2 to 20 C. This work provides a facile design strategy for constructing a superb artificial SEI layer for high-performance LMBs. [ABSTRACT FROM AUTHOR]

Converting CO2 to value‐added chemicals, e. g., CH3OH, is highly desirable in terms of the carbon cycling while reducing CO2 emission from fossil fuel combustion. Cu‐based nanocatalysts are among the most efficient for selective CO2‐to‐CH3OH transformation; this conversion, however, suffers from low reactivity especially in the thermodynamically favored low temperature range. We herein report ultrasmall copper (Cu) nanocatalysts supported on crystalline, mesoporous zinc oxide nanoplate (Cu@mZnO) with notable activity and selectivity of CO2‐to‐CH3OH in the low temperature range of 200–250 °C. Cu@mZnO nanoplates are prepared based on the crystal‐crystal transition of mixed Cu and Zn basic carbonates to mesoporous metal oxides and subsequent hydrogen reduction. Under the nanoconfinement of mesopores in crystalline ZnO frameworks, ultrasmall Cu nanoparticles with an average diameter of 2.5 nm are produced. Cu@mZnO catalysts have a peak CH3OH formation rate of 1.13 mol h−1 per 1 kg under ambient pressure at 246 °C, about 25 °C lower as compared to that of the benchmark catalyst of Cu−Zn−Al oxides. Our new synthetic strategy sheds some valuable insights into the design of porous catalysts for the important conversion of CO2‐to‐CH3OH. [ABSTRACT FROM AUTHOR]

Due to the surface inhomogeneity of the solid supports, direct growth of uniform bimetallic nanoparticles (NPs) with controllable structure and size thereon is particularly challenging. Herein, a surface‐confinement strategy is reported to directly prepare ultrafine bimetallic PtM NPs (MFe, Cu, and Co) with structure of core‐shell or intermetallic compounds on an N functionalized carbon support (NC). It is found that the N species of NC support can atomically disperse metal cations of precursors, which largely renders uniform nucleation and growth of bimetallic NPs and fine structure modulation of them. In another regard, metal transfer is confined to a narrow region on NC via N‐mediation, hence greatly favoring localized particle growth and formation of ultrafine bimetallic NPs. Remarkably, the ultrafine 3.1 ± 0.7 nm intermetallic Pt3Fe NPs on NC displayed excellent catalytic activity and durability toward electrochemical hydrogen evolution reaction. [ABSTRACT FROM AUTHOR]

It is extremely challenging to controllably synthesize rare earth‐containing nanoalloys due to the ultralow standard reduction potential of rare earth metals. Here, a surface‐confined strategy to prepare ultrafine Pt‐rare earth nanoalloys on a series of N‐functionalized supports is reported. It proves that by surface N‐metal coordination, the metal cations of precursors are atomically dispersed on support, which greatly favors uniform nucleation and growth of particles upon reduction. Moreover, the moderate metal transfer barrier from N ensures particle growth in a confined region to form ultrafine nanoalloys. Using this method, ultrafine PtLa, PtY, and PtDy nanoalloys are prepared on N‐functionalized supports such as carbon, zeolite, and Al2O3. Notably, the PtLa nanoalloys on N‐functionalized zeolite show superior activity and durability for propane oxidation. The strategy is expected to provide guidelines for preparing highly efficient rare earth‐containing nanoalloys for catalysis applications. [ABSTRACT FROM AUTHOR]

AbstractBacterial Mn(II) oxidation is believed to play a dominant role in accelerating the rate of Mn biomineralization in nature. Commonly, bacteria employ two ways involving Mn(II) oxidases and reactive oxygen species to oxidize Mn(II). In this study, a new strategy for bacterial Mn(II) oxidation involving the pyocyanin, a greenish blue phenazine pigment from Pseudomonas aeruginosa, was discovered. To begin with, a bacterial strain L3 was isolated from soils and identified as Pseudomonas aeruginosa, which exhibited the ability of Mn(II) oxidation. Next, the pyocyanin was purified from strain L3 cultures and proven to be involved in Mn(II) oxidation. Particularly, the oxidation of Mn(II) by pyocyanin was dependent on its ambient pH. In comparison with pH of 5 and 7, pyocyanin (the initial value of OD387 was 0.56 at pH of 2) showed a stronger capability of oxidizing Mn(II) at pH of 9, reaching 144.03 μg L−1 of Mn oxides after 108 h of Mn(II) oxidation, while pyocyanin ultimately produced 43.81 μg L−1 at pH of 7 and 3.32 μg L−1 at pH of 5, respectively. Further, strain L3 cultures were fractionated into three parts, i.e., the cell culture solution, fermentation supernatant, and cell suspension, and the Mn(II)-oxidizing activity was found to be distributed in the cell culture solution and fermentation supernatant, as evidenced by the formation of blackish glossy Mn oxides. Specifically, in the first half, the rate of Mn(II) oxidation by the fermentation supernatant was higher than that by the cell culture solution, whereas in the second half, the cell culture solution showed the much higher Mn(II)-oxidizing activity compared to the fermentation supernatant. Last but not least, the collective results from mineral characterization demonstrated that, the Mn oxides produced by P. aeruginosa strain L3, either by the cell culture solution or by the fermentation supernatant, were bixbyite-type Mn2O3 with poor crystallinity. [ABSTRACT FROM AUTHOR]

Density is the most important parameter determining the performance of indium-tin oxide (ITO) targets. However, the full densification of ITO ceramics is extremely difficult. Previously reported strategies are based on the addition of components such as sintering aids or significant process adjustments. In this study, we aimed to realise the full densification of an ITO target by the fine regulation of parameters involved in the conventional pressure-less sintering process. The phase transitions, BET surface area, and particle size changes of indium-tin co-precipitated nanoprecursors sintered at different temperatures were studied. Moreover, the effects of the ITO powder state and sintering temperature on the density, resistivity, and microstructural uniformity of the ITO target were investigated. The results showed that the existence of rhombohedral In 2 O 3 in the ITO powder and ceramic sintering temperature are vital to the full densification of the ITO target. Density was found to dominate ITO-target resistivity when the sintering temperature was <1585 °C. In this study, an extraordinary high-density (99.81 %), low-resistivity (1.707 × 10−4 Ω cm), and uniform-microstructured ITO target is prepared under optimised operation conditions. [ABSTRACT FROM AUTHOR]

Density is the most important parameter determining the performance of indium-tin oxide (ITO) targets. However, the full densification of ITO ceramics is extremely difficult. Previously reported strategies are based on the addition of components such as sintering aids or significant process adjustments. In this study, we aimed to realise the full densification of an ITO target by the fine regulation of parameters involved in the conventional pressure-less sintering process. The phase transitions, BET surface area, and particle size changes of indium-tin co-precipitated nanoprecursors sintered at different temperatures were studied. Moreover, the effects of the ITO powder state and sintering temperature on the density, resistivity, and microstructural uniformity of the ITO target were investigated. The results showed that the existence of rhombohedral In 2 O 3 in the ITO powder and ceramic sintering temperature are vital to the full densification of the ITO target. Density was found to dominate ITO-target resistivity when the sintering temperature was <1585 °C. In this study, an extraordinary high-density (99.81 %), low-resistivity (1.707 × 10−4 Ω cm), and uniform-microstructured ITO target is prepared under optimised operation conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • High efficiency Au/TiO 2 for CTH of 4-nitrostyrene by NH 3 BH 3 is reported. • The presence of Au-OH accelerates dehydrogenation of NH 3 BH 3. • The existence of Au-OH could promote the adsorption of 4-nitrostyrene. • Low-coordinated Au also promotes the adsorption of 4-nitrostyrene. Transfer hydrogenation of unsaturated nitro compounds by NH 3 BH 3 is an important hydrogenation reaction. Among them, Au/TiO 2 catalysts could achieve good activity for this reaction, but often have problem such as the selectivity decline. In this study, we prepare PVA-wrapped Au nanoparticles, and then load them onto TiO 2 support to obtain Au/TiO 2 catalyst. We demonstrate that the prepared catalyst after calcination has achieved high activity (>99 %) and high selectivity (99 %) in the transfer hydrogenation of 4-nitrostyrene (4-NS) within 30 min by NH 3 BH 3 under ambient temperature and pressure. In addition, the catalyst can still maintain high selectivity (>97 %) after being recycled for 5 times, showing its remarkable stability and reusability. Characterization results and density functional theory (DFT) calculations showed that the presence of Au-OH species accelerates the dehydrogenation of NH 3 BH 3 and thus enhances the catalytic activity. Meanwhile, Au-OH species and low-coordinated Au are beneficial to enhance nitro adsorption and improve the selectivity of transfer hydrogenation reaction. This study provides new ideas for the rational design of high-performance green gold catalytic transfer hydrogenation reactions. [ABSTRACT FROM AUTHOR]

Arsenopyrite is a common arsenic-containing mineral that is often closely associated with sulfide minerals, such as pyrite, chalcopyrite, pyrrhotite, galena, and sphalerite, and with precious metals, such as gold and silver. The selective inhibition of arsenopyrite is an important method used to reduce the arsenic content of processed products, the cost of arsenic removal in metallurgical processes, and its impact on the environment. In this study, we discovered a chemical sodium, m-nitrobenzoate (m-NBO), that can effectively inhibit the flotation behaviors of arsenopyrite via sodium butyl xanthate (NaBX), and these effects were studied by flotation experiments. The results showed that, using NaBX as a collector, arsenopyrite had good floatability under acidic conditions, but the floatability decreased under alkaline conditions. Furthermore, the organic inhibitor m-NBO had a significant inhibitory effect on arsenopyrite under alkaline conditions. In addition, the adsorption between m-NBO and NaBX was competitive, and a hydrophilic layer formed on the surface of arsenopyrite. The passivation film prevents dixanthogen from being adsorbed on the surface of the mineral. Due to the effect of m-NBO on arsenopyrite, the redox potential and oxide content of the arsenopyrite surface increased, the hydrophobicity of the arsenopyrite surface was reduced, and the flotation of arsenopyrite was inhibited. These results provide options for separating multimetal sulfide minerals and arsenic-containing minerals. [ABSTRACT FROM AUTHOR]

[Display omitted] • DL adsorption on sphalerite surfaces with different Fe substitutions is analyzed. • Fe substitution enhances the overall acidity and improves the reactivity. • PDOS and charge transfer analyses confirm space matching and orbital matching. • The micro-flotation and contact angle show strong adsorption of DL on marmatite. • DL is a feasible green selective depressant. Conventional flotation processes often employ cyanide as a depressant for sphalerite, posing environmental concerns. This study investigates the adsorption of 2-Amino-3-mercaptopropionic acid (also known as DL-Cysteine) on sphalerite surfaces with varying degrees of Fe substitution using density functional theory calculations. The focus encompasses electronic properties, charge transfer, and orbital coordination. The potential of DL-cysteine as a sphalerite depressant was assessed and subsequently confirmed experimentally. Our findings indicate that Fe substitution increases the acidity of the mineral surface, thereby enhancing its reactivity to readily interact with the S, O, and N atoms abundant in lone-pair electrons. The Fe-substituted sphalerite surface primarily adsorbs DL-cysteine through interactions with -SH and –NH 2 groups on Fe ions, in contrast to those on Zn ions. Analyses of the partial density of states and charge transfer confirm the spatial and orbital compatibility in the system. Moreover, micro-flotation tests, contact angle measurements, and scanning electron microscopy combined with energy-dispersive X-ray spectroscopy substantiate that DL-cysteine efficaciously adsorbs onto marmatite surfaces, thereby reducing their hydrophobicity. On the contrary, the adsorption strength of sodium diethyldithiocarbamate on the mineral surface is significantly weaker. Overall, the potent adsorption capability of DL-cysteine makes it a viable, eco-friendly depressant alternative for marmatite. [ABSTRACT FROM AUTHOR]

[Display omitted] • TA, a biodegradable plant polyphenol, was introduced as a depressant in the flotation separation of chalcopyrite and talc. • TA could be selectively adsorbed on the surface of talc to separate talc and chalcopyrite. • The interaction of TA with talc was physical rather than chemical. • The layered structure of talc and the phenolic hydroxyl structure of TA cause TA to selectively adsorb on talc surface. In this paper, the effect of Tannic acid (TA), a green, biodegradable plant polyphenol, as a talc depressant on the separation behavior of talc and chalcopyrite was investigated. The results of micro-flotation studies revealed that at a TA dosage of 20 mg/L at pH 7, talc recovery was barely 10 % whereas chalcopyrite recovery remained above 90 %, indicating that TA can selectively depress talc flotation. The results of the artificial mixed minerals test further confirmed the depressive effect of TA. The adsorption results showed that the adsorption density of TA on talc was greater than that on chalcopyrite surface. Similar conclusions were observed in zeta potential tests. It is noteworthy that the zeta potential of the chalcopyrite treated with TA and butyl xanthate sodium continued to shift negatively in comparison to the zeta potential of chalcopyrite treated with TA alone, suggesting that butyl xanthate sodium can continue to adsorb on the surface of chalcopyrite following TA treatment. Besides, X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy tests concluded that TA adsorbs on talc surface by physical (hydrophobic) interaction. Differences in the crystal structures of chalcopyrite and talc, as well as the large number of phenolic hydroxyl structures contained in TA, are the main driving forces for the selective adsorption of TA on the talc surface. This work provides an insight to the selection of inhibitors for the separation of chalcopyrite and talc, particularly from the perspective of the hydrophobic effect of the talc layered structure. [ABSTRACT FROM AUTHOR]

A novel flotation depressant with selective adsorption properties based on orbital matching was used to replace cyanide for the flotation separation of jamesonite and marmatite. The presence of characteristic groups, such as the sulfhydryl and amino groups, enhanced the adsorption of DL-cysteine on the metal ions (Zn2+ and Fe2+) on marmatite surface. The adsorption of DL-cysteine on the marmatite surface significantly enhanced the surface hydrophilicity and decreased the flotation recovery. [Display omitted] • DL-cysteine is a potential green depressant for marmatite flotation. • DL selectively depressants marmatite but has little effect on jamesonite floatability. • The adsorption between DL and marmatite hinders DDTC adsorption. • Coordination theory analysis confirmed the complexation between DL and Fe2+/Zn2+. Flotation is an effective separation technique for removing marmatite, a harmful impurity, from jamesonite. In this study, DL-cysteine (DL) was used as an eco-friendly flotation agent for the targeted separation of jamesonite from marmatite. Micro-flotation experiments, zeta potential measurement, Fourier transform infrared, and X-ray photoelectron spectroscopies show that DL can combine with metal ions on the surface of marmatite through chemical complexation, thereby selectively hindering the flotation of marmatite. The competitive adsorption of DL and sodium diethyldithiocarbamate on marmatite surface is the main factor leading to the change in marmatite floatability. The flotation coordination theory confirms that Fe2+ is the main active site on marmatite surface. π-back-bonding and σ-bonding are the main driving forces for the adsorption of DL on marmatite surface. Importantly, DL can be produced using animal hair as a raw material. It is, thus, a low-cost material with good environmental compatibility and high selectivity and a potential green depressant for marmatite flotation. [ABSTRACT FROM AUTHOR]

Due to the state transition of variable-valence ions during the solid-state reaction, the reaction mechavnism is complex. As one of the function materials in supercapacitors and catalysts, there is much research on the property and function mechanism of MnCo 2 O 4. But it's necessary to study the chemical reaction and a productive method for realizing wide application. In this paper, solid-state reaction method with high efficiency was applied to produce MnCo 2 O 4 and investigated the reaction process of oxides, the formation mechanism of MnCo 2 O 4 , respectively. Thermodynamic and roasting experiments of single metal oxides demonstrated the actual stability of MnO 2 and Co 3 O 4 in the air. Furthermore, Roasting experiments on different metal oxide systems revealed Mn 2 O 3 and Mn 3 O 4 were the effective reactants of MnCo 2 O 4 , which reacted with Co 3 O 4 respectively to produce MnCo 2 O 4. Moreover, the optimum condition of the preparation of MnCo 2 O 4 was determined to be 1150 ℃ with a 90-minute in a 3:2 molar ratio of MnO 2 and Co 3 O 4. MnCo 2 O 4 were composed of Mn2+, Mn3+, Co2+, and Co3+, the property of Mn-O and Co-O bonds at 1.50 Å and 1.54 Å all including tetrahedral and octahedral sites with a bond length of 1.9–1.92 Å and 1.93–1.94 Å, respectively. Mn and Co atoms are located at octahedral sites with two coordinated distances: Me Oh -Me Oh , Me Oh -Me Td. The migration behavior of elements in MnO 2 -Co 3 O 4 diffusion couple was found to manganese move to Co-based and generate a porous MnCo 2 O 4 at the interface. The formation mechanism of spinel-type MnCo 2 O 4 was explained: While Co 3 O 4 was activated, Mn4+ was decomposed to Mn2+ and Mn3+ in the oxidation roasting process. Further, Mn2+ and Mn3+ replaced part of tetrahedral Co2+ and octahedral Co3+ in [Co(2+)][Co(3+)] 2 O 4 to form a spinel-type [Mn(2+)Co(2+)][Mn(3+)Co(3+)] 2 O 4. [Display omitted] • Mn 2 O 3 and Mn 3 O 4 can directly react with Co 3 O 4 to produce MnCo 2 O 4 by roasting. • Mixing-valence Mn and Co atoms are located at octahedral sites with two coordinated distances: Me Oh -Me Oh , Me Oh -Me Td (Me= Mn, Co) • The process of atomic substitution is a pivotal step in the formation of MnCo 2 O 4 [ABSTRACT FROM AUTHOR]

[Display omitted] • SA selectively depressed marmatite and achieves excellent Pb-Zn separation. • SA strongly chemically complexes with metal ions on the surface of marmatite. • Fe2+ easily forms π-backbonding with SA and dominates the adsorption of SA. • SA is a low toxicity and effective alternative to traditional marmatite depressants. In this study, sodium alginate (SA) is proposed as a flotation depressant for the selective separation of galena and marmatite. The effect of SA on the flotation performance of galena and marmatite was investigated using sodium butyl xanthate (SBX) as the collector. The adsorption behavior of SA on the mineral surface was theoretically analyzed. The micro-flotation results demonstrated that the flotation of marmatite could be selectively depressed through the addition of SA before SBX at pH = 11. The contact angle, FTIR, XPS, and zeta potential results demonstrated that SA could be selectively adsorbed on the marmatite surface, thereby hindering the subsequent adsorption of the collector and affecting its flotation. A coordination theory analysis further confirmed that Fe2+ was the active site on the marmatite surface. SA can form π-backbonding with Fe2+ on the surface of the marmatite, resulting in strong adsorption but weaker interactions with Zn2+ and Pb2+. Overall, the high selectivity and environmental compatibility of SA make it an effective green depressant for the flotation separation of marmatite. [ABSTRACT FROM AUTHOR]

[Display omitted] • DFT calculations revealed the mechanism of flotation depressant by nitrobenzoates. • All positional isomers of nitrobenzoates had same reactive sites. • The unoccupied π orbitals in flotation depressant can form covalent bonds with π orbitals on the mineral surface. Nitrobenzoate can effectively depressor the flotation of arsenopyrite, making theoretical studies to elucidate the mechanism essential. This study investigates the structure-reactivity relationship of nitrobenzoate as a flotation depressant for arsenopyrite by density functional theory calculations. The results revealed that O/N heteroatoms participated in the formation of chemical bonds with the metal atoms on the mineral surface as o-nitrobenzoate, m-nitrobenzoate, and p-nitrobenzoate molecules and had significant chemical reactivities. The interaction of the flotation depressant with the mineral surface followed the order: m-nitrobenzoate > p-nitrobenzoate > o-nitrobenzoate, which was further confirmed by flotation experiments. Furthermore, the reactive sites of the three nitrobenzoate isomers were investigated, and the results revealed that all three isomers had the same reactive sites, but interacted differently with the metal atoms. [ABSTRACT FROM AUTHOR]

[Display omitted] • Study on adsorption difference of sodium alginate on galena and marmatite. • Iron atom is the main active site on the surface of marmatite. • The existence of iron enhances the bonding strength between SA and marmatite. • Fe2+ can form π-backbonding with SA by providing a pair of π electrons. • vdW, steric effects and weak covalent interactions dominate the adsorption of SA. In this study, density functional theory (DFT) was used to simulate the adsorption of sodium alginate (SA) on the surface of sphalerite, marmatite (1 1 0), and galena (1 0 0). The results showed that SA was mainly adsorbed on the surface of sphalerite by van der Waals interaction and steric hindrance without iron substitution. However, the substitution of iron on the surface of sphalerite significantly increased the adsorption energy of SA. In particular, the substitution of a large amount of iron significantly changed the surface properties of sphalerite, and the adsorption of SA on the surface of sphalerite changed from physical to chemical adsorption. The results of a density of states comparative analysis, charge transfer, and coordination theory analysis also confirmed that the adsorption of SA on a marmatite surface was easier and more stable than that on galena or sphalerite. Overall, the high selectivity of SA is expected to make it a green depressant of marmatite. [ABSTRACT FROM AUTHOR]

Electrochemical reduction of CO 2 to multi-carbon products is very attractive yet particularly challenging due to the low efficiency of C-C coupling over currently used electrocatalysts. In this work, we report a dual-atom catalyst (Cu 2 /NC) capable of selectively promoting electro-reduction of CO 2 to C 2 H 4. The Faradaic efficiency of CO 2 -to-C 2 H 4 over the Cu 2 /NC is up to ∼34.9% with a current density of 33.6 mA·cm−2. By contrast, its Cu single-atom counterpart only generates CO without forming C 2 H 4. The density functional theory (DFT) calculations reveal that the Cu-Cu sites largely promote the adsorption of *CO and reduce the energy barrier of C-C coupling between the adsorbed *CO relative to that of the single Cu sites, which accounts for the high C 2 H 4 selectivity of the Cu 2 /NC. [Display omitted] • Highly efficient Cu dual-atom catalysts were prepared to catalyze CO2RR. • Compared with Cu single-atom catalyst, dual-atom catalyst was more favorable to reduce CO2 to multi-carbon product C2H4. • DFT calculations revealed that the energy barrier of C-C coupling was largely reduced on the dual Cu catalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • The method of promoting ilmenite flotation involves adding BHA to the mill was proposed. • The BHA synergistic mechanical activation can promote ilmenite flotation significantly. • The mechanism of BHA synergistic mechanical activation on ilmenite flotation was revealed. In this paper, the effect of the benzohydroxamic acid (BHA) synergistic mechanical activation on ilmenite flotation was systematically investigated. Flotation results revealed that the flotation recovery of ilmenite significantly increased with the addition of BHA before grinding as compared to the conventional process flow. Similar trend was observed in the flotation test of artificial mixed mineral. The addition of BHA to the mill has little effect on the size distribution of ilmenite, but it can increase the content of crystal surface (1 0 4) with the lowest surface energy of ilmenite. The results of Fourier-transform infrared spectroscopy (FT-IR) analysis showed that the addition of BHA before grinding resulted in improving the intensity and kinds of characteristic absorption peaks of BHA on the ilmenite surface. The addition of BHA to the mill effectively facilitated the interaction between ilmenite and BHA. Besides, the result of flotation kinetics demonstrated that the flotation kinetics of ilmenite could be well evaluated with the first-order kinetic model. And the flotation kinetic constant was improved by adding BHA before grinding, which was conducive and beneficial for enhancing the ilmenite flotation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Effect of differently structured collectors at the gas–liquid interface was discovered. • The mechanism of the effect of DDTC/BX on froth stability was shown. • Interface analysis can be enhanced by combining simulation and experiments. • This method can help predict the influence of collector structures on frother solution. The effect of sodium diethyldithiocarbamate (DDTC)/butyl xanthate (BX) on froth stability formed by methyl isobutyl carbinol (MIBC) was investigated using experiments and molecular simulations, and the mechanism of the effect of differently structured collectors on the interfacial water at the gas–liquid interface was discovered. The froth stability indicated that DDTC and BX could considerably reduce the solution surface tension, increase the froth half-life, and maximum froth layer volume compared with MIBC solutions. Particularly, in the BX-containing system, the froth half-life reached an astonishing 160 s, and the maximum froth layer volume reached 270 ml. To explain this observation, this study used molecular simulations to provide new insights into the interactions between DDTC/BX and MIBC and water at the molecular level. The results demonstrate that the density of water molecules at the interface of the DDTC/BX solution is higher than that of the MIBC solution, the orientation of water molecules at the interface is more ordered, and the hydrogen bonds are more tightly connected. The results are consistent with the experimental data, demonstrating that DDTC/BX improves the significance of MIBC on water molecule rearrangement at the gas–liquid interface. This study can offer a reference for studying the effect of collector structure on frother performance and can offer important guidance for the design of mineral flotation reagents. [ABSTRACT FROM AUTHOR]

The selective interaction of reagents with mineral surfaces is the core basis for mineral flotation separation. Herein, the interaction mechanism of a novel depressant m-nitrobenzoate with arsenopyrite has been investigated with the help of density functional theory (DFT) simulations, supplemented by micro-flotation tests and X-ray photoelectron spectroscopy (XPS) analyses. It is found that the adsorption of m-nitrobenzoate on the surface of arsenopyrite was mainly due to the effect of –NOO– in m-nitrobenzoate. These findings provide a clear correlation between the experiments and DFT, indicating that the –NOO– in m-nitrobenzoate can adsorb on the surface of arsenopyrite via a covalent bond, thereby realizing the depress of arsenopyrite. [Display omitted] • The oxidative properties of the -NOO- exacerbate the oxidation of arsenopyrite. • The presence of π-back bonding favors the interaction between ligands and metal ions on the mineral surface. • The lone pair of electrons of the depressant gives the empty orbital of the surface metal ion to form a positive σ bond. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel additive, 2,2,2-Trifluoroethyl trifluoroacetate, was found can construct a flaky LiF-rich SEI layer. • Using additive ensures a long lifespan up to 750 h in Li|Li cell and a higher CE of 99.7% in Li|Cu cell. • A stable cycling performance and better rate capability of LMBs is achieved. As the holy grail anode, lithium (Li) metal has attracted considerable interest in developing next-generation high-energy–density batteries. However, Li dendrites due to the poorly protected solid electrolyte interphase (SEI) during the Li plating process largely limit the Li application. Here, we report an effective electrolyte additive, i.e., 2,2,2-Trifluoroethyl trifluoroacetate (2,2,2-TFTF) as highly efficient inhibitor against growth of Li dendrites by facile mediation of SEI layer. DFT calculations and a series of characterization results indicate that the additive greatly favors formation of more protective SEI layer on the Li anode and homogeneous Li deposition. Strikingly, with 4% additive, the Li|Li cell showed a long cycle life of 750 h and the Li|Cu cell afforded an ultrahigh Coulombic efficiency (CE) of 99.7%. Moreover, the Li|LFP cell with 4% additive exhibited high-capacity retention and better rate performance, especially at 5C. The additive 2,2,2-TFTF offers a nontraditional option for high-performance lithium metal batteries with simplicity and saving. [ABSTRACT FROM AUTHOR]

In this study, a novel method of promoting cassiterite flotation involves adding Pb-BHA (Pb(NO 3) 2 -benzohydroxamic acid) complexes to the cassiterite grinding process was investigated. The flotation result showed that adding Pb-BHA complexes before grinding had a marked effect on the cassiterite flotation recovery. The cassiterite flotation recovery with Pb-BHA complexes added before grinding was higher 42.80% than that of Pb-BHA complexes added after grinding. Moreover, it revealed a similar trend for artificial mixed minerals of cassiterite and quartz, in which the Sn recovery and grade of concentrate increased by 34.71% and 1.11%, respectively. The Fourier-transform infrared spectroscopy (FT-IR) analysis revealed that adding Pb-BHA complexes before grinding enhanced the adsorption of Pb-BHA complexes on the cassiterite surface. And the X-ray photoelectron spectroscopy (XPS) analysis demonstrated that the chemical environment of N in Pb-BHA complexes was changed in the grinding, making it more easily to adsorb on cassiterite surface. [Display omitted] • Adding Pb-BHA before grinding has a marked effect on the cassiterite flotation. • The Pb-BHA were chemically adsorbed on the cassiterite surface. • The chemical state of N was changed in grinding, promoting cassiterite flotation. [ABSTRACT FROM AUTHOR]

• Oxygen vacancy-enriched Co 3 O 4 nanowire arrays decorated on nickel foam is used for a dendrite-free Li metal anode. • The O vacancy -enriched metal oxides meet the ionic/electronic diffusion kinetics at the initial stage of lithium deposition. • The lithium utilization rate of red-Co 3 O 4 /NF at the current density of 1 mA cm−2 is 98.5%. [Display omitted] Lithium metal as a promising anode material has been widely applied in many advanced high-energy density batteries. However, uncontrollable Li dendrite formation and infinite volume expansion in lithium anode result in short lifespan and severe safety hazards. In this contribution, we report that utilization of oxygen vacancy-enriched Co 3 O 4 nanowire arrays as lithiophilic material is an effective strategy to obtain ultra-long stable lithium metal anode. The oxygen vacancy can serve as electronic charge carrier to facilitate electron transfer. Moreover, it can induce the generation of local electric field to accelerate lithium ions migration and enable uniform Li+ distribution, which are beneficial for homogeneous lithium nucleation. Combining the excellent ionic/electronic diffusion and the volume buffer offered by the nanowire arrays, the obtained electrode shows high coulombic efficiency of 98.5% at 1 mA cm−2 for 230 cycles. [ABSTRACT FROM AUTHOR]

• Lead - modification effectively improved the floatability of specularite. • Pb2+ and Pb(OH)+ components interacted with specularite surface to form -O-Pb and Fe-O-Pb complexes. • The -O-Pb and Fe-O-Pb complexes exhibited strong reactivity towards sodium oleate. • Modification mechanism of Pb2+ ions on the specularite surface was explained. Specularite is generally recovered by flotation, but its floatability is relatively weak. Activation is an effective method to improve the floatability of minerals. Therefore, finding an economic and effective activator to improve the recovery of specularite is an important research direction. In this study, lead nitrate as an activator was found and confirmed to improve the floatability of specularite. Its activation mechanism was further investigated by various analytical methods. The micro-flotation tests results showed that the recovery of specularite increased from 69.57% to 92.47% at a Pb2+ concentration of 3 × 10-5 mol/L, an approximately 23% increase, indicating that Pb2+ could obviously activate specularite. The SEM-EDS results illustrated that the content of Pb on the specularite surface apparently increased after specularite treatment with lead nitrate, which confirmed the adsorption of Pb species on the surface of specularite. Zeta potential results showed that the zeta potential positively shifted within the pH range from 3 to 11, which was beneficial to the occurrence of electrostatic adsorption and chemisorption between negatively charged oleate species and specularite. XPS results revealed that lead species mainly adsorbed on the O atoms of Fe-O and Fe-OH at the specularite surface, and Pb atoms became new sites to interact with sodium oleate. In addition, Pb2+ and Pb(OH)+ were the predominant components that interacted with the specularite surface and formed -O-Pb and Fe-O-Pb complexes, which considerably increased the number of reactive sites on the specularite surface. After oleate components interacted with Pb-modified specularite, a denser hydrophobic layer was generated on the surface of specularite, which intensified the floatability of specularite. [ABSTRACT FROM AUTHOR]

Recently, designing new catalysts based on topological quantum materials has attracted much research interest. Here, we have explored WTe 2 , a type-II Weyl semimetal, as an effective electrocatalyst for hydrogen evolution reaction (HER). New nanostructure am -WPO@WTe 2 has been constructed based on WTe 2 , in which the crystalline P-doped WTe 2 core is covered by amorphous phosphate species. Due to the unique core-shell structure, the HER catalytic performance of am -WPO@WTe 2 has been greatly enhanced, delivering a low overpotential of 220 mV and 280 mV at the current density of 10 mA/cm2 in acidic and alkaline electrolytes, respectively, with outstanding durability. The improved HER electrocatalytic performance could be attributed to the abundant active sites provided by the amorphous phosphate on the surface of the catalyst and the enhanced electron transfer due to the crystalline P-doped WTe 2 core. This strategy of surface modification of Weyl semimetal may open new opportunities in utilizing topological quantum materials for application in catalysis. [Display omitted] [ABSTRACT FROM AUTHOR]