Membrane capacitive deionization (MCDI) is a promising Li-extraction technology from salty brine to meet the growing demand for lithium sources. In this work, a Li+-selective quaternized poly(ether sulfone) coupled LiMn1.9Cr0.1O4@carbon cloth (LMC@CC/QPES) is fabricated via a rapid UV-curing method and used as the flexible Li-extraction electrode in the MCDI system. The Li-extraction results for old brine from West Taijinar confirm that the optimal capacity can reach 28.57 mgg(-1) with a retention rate of 82.36% after 200 cycles. This is ascribed to the stereoscopic carbon cloth as a current collector improving the active loading and charge transfer and the UV-curing polymer binder as a buffer layer repressing the initial manganese dissolution of spinel LiMn1.9Cr0.1O4. Importantly, the LMC@CC/QPES electrode exhibits an enhanced Li+ selectivity (Li+/Mg2+ separation coefficient > 280) through ion sieving by the spinel lattice with electrostatic repulsion by the quaternized membrane. Considering the green preparation of the Li-extraction electrode, the assembled MCDI system using QPES assisting the LMC@CC electrode can provide considerable economic benefits for lithium recovery from old brine.

In order to further boost the electrocatalytic performances of small organic molecule oxidation and maintain the structure stability of Pd-based catalyst during long cycle, a new ligand compound (i.e. propanethiol) was introduced into the Pd/C anode catalyst to prepared Pd/C-SH catalyst by two main steps of propanethiol adsorbed on Vulcan XC-72 carbon (C-SH) by water bath impregnation method and Pd nanoparticles anchored on the functionalized C-SH support by improved liquid reduction method. Results showed that the Pd nanoparticles with high dispersion in Pd/C-SH catalyst were obtained and their particle size distribution was in the range of 1.6-4.8nm. Moreover, Pd particle size became smaller with the modification of propanethiol, indicating that propanethiol could facilitate the formation of smaller Pd. Electrochemical measurements showed that the mass activity of Pd/C-SH (1229mAmg-1) was 4.6 times that of Pd/C (267mAmg-1) towards formic acid oxidation. Higher stability (30 times higher than Pd/C) and more faster charge transfer kinetics of oxidation reaction were also recorded for Pd/C-SH catalyst. The enhancement of electrochemical performances of Pd/C-SH catalyst might be related to highly dispersed Pd with reduced particle size, adjusted electronic structure of Pd as well as maintained stable Pd structure and particle size.

CoFe layered double hydroxide (CoFe LDH) can serve as a cost-effective and active electrocatalyst for oxygen evolution reaction (OER). Unfortunately, it still faces the challenges of low electrical conductivity, stability and limited active sites to achieve the threshold current density with low overpotential. In this study, the strategy of Ru doped together with air plasma treatment was proposed to improve the OER performances of CoFe LDH. The doping of Ru and air plasma process could induce electronic interaction and the oxygen defects to regulate the electronic structure. Significantly, the air plasma treated Ru doped CoFe LDH (P-Ru-CoFe LDH) catalyst achieved superior catalytic properties to the CoFe LDH and RuO2 benchmarks, which was demonstrated by a relatively smaller overpotential of 275 mV at 10 mA cm(-2) and a lower Tafel slope of 107 mV dec(-1) for OER. In addition, it also maintained an excellent stability in long-term chronoamperometry test. In general, P-Ru-CoFe LDH catalyst could boost the OER performance through intrinsic electronic structure adjustment with Ru doped and air plasma process. These findings provide an effective pathway to design/develop OER electrocatalysts with high performances by internal electron coupling effects.

Black phosphorus (P(black)) shows impressive physicochemical features for electrocatalysis including adjustable bandgap and high charge carrier mobility. However, the existence of solitary electron pairs in exfoliated P(black) nanosheets (EP(black)) leads to rapid surface degradation, resulting in unfavorable durability. Herein, a P–O bridge was created in the heterostructure EP(black)/vanadium-doped cobalt hydroxide with oxygen vacancy (EP(black)/V–CoO2-xH2) to stabilize and expedite oxygen evolution reaction (OER) activity. By bonding the solitary electron pairs of EP(black) and oxygen species (OH*) of V–CoO2-xH2, the distinctive P–O bridge resulted in important ligand effects that improved not merely the stability of EP(black) but effectively regulated the electron configuration of V–CoO2-xH2. DFT simulations revealed that directional interfacial electron migration from V–CoO2-xH2 to EP(black) facilitated the formation of pivotal OER intermediates and hence boosted OER activities. This study proposes a novel strategy to enhance the electrochemical properties of EP(black), which could be extended to a wide range of high-performance electrocatalyst systems.

Designing cost-effective and durable bifunctional electrocatalysts with high activity for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is crucial for large-scale hydrogen production through water splitting. However, many electrocatalysts undergo surface or bulk reconstruction, leading to an unstable catalytic activity. In this study, we present a facile N-2 plasma strategy to enhance the electrocatalytic activity of cobalt-fluoride-oxide (CoFO, herein NCoFO) nanosheets while maintaining reasonably stable performance. The optimized NCoFO nanosheets grown on carbon cloth through a 60 s N-2 plasma treatment (NCoFO/CC-60) exhibit remarkable performance with low overpotentials of 203 mV and 230 mV at 10 mA cm(-2) for the HER and the OER, respectively. Density functional theory calculations revealed that the enhanced catalytic performance is attributed to the regulated local electronic configuration resulting from plasma treatment. Furthermore, the assembled alkaline electrolyzer NCoFO/CC-60||NCoFO/CC-60 requires an extremely low voltage of 1.48 V to attain 10 mA cm(-2) for over a 150 h operation, which is superior to the values obtained for Pt/C||RuO2 (1.50 V) and CoFO/CC||CoFO/CC (1.55 V).

Hybrid sodium-air batteries (HSABs) offer a possible solution for large-scale energy storage due to high theoretical energy density and abundant sodium resource. However, ORR suffers from sluggish kinetics with multielectron transfer step, resulting in high overpotential. Herein, we demonstrated electronic agglomeration effect on CoO/CNT to controllably activate catalytic active species to boost ORR by atomic surface engineering. By virtues of superior electron transfer ability and optimal adsorption energy of reactive species, activities of F- surface-decorated electrode could be greatly improved. DFT revealed that F- induced electronic agglomeration on Co -O sites, resulting in high electron density of Co and intense combination with OH* in the first step. Surprisingly, the F-CoO/CNT showed favorable ORR activity and enabled advanced HSAB with low overpotential gap of 0.14 V. This work provides a new view about atomic and electronic structure engineering for activating active species, which will pave a new way for designing electrode materials.

In order to determine the polarizability and hyperpolarizability of a molecule, several key parameters need to be known, including the excitation energy of the ground and excited states, the transition dipole moment, and the difference of dipole moment between the ground and excited states. In this study, a machine-learning model was developed and trained to predict the molecular polarizability and second-order hyperpolarizability on a subset of QM9 data set. The density of states was employed as input to the model. The results demonstrated that the machine-learning model effectively estimated both polarizability and the order of magnitude of second-order hyperpolarizability. However, the model was unable to predict the dipole moment and first-order hyperpolarizability, suggesting limitations in its ability to predict the difference of dipole moment between the ground and excited states. The computational efficiency of machine-learning models compared to traditional quantum mechanical calculations enables the possibility of large-scale screening of molecules that satisfy specific requirements using existing databases. This work presents a potential solution for the efficient exploration and analysis of molecules on a larger scale.

Hybrid solid electrolytes (HSEs) with satisfactory ionic conductivities, good flexibilities, and ideal interface compatibilities are crucial for the development of all‐solid‐state lithium‐metal batteries. However, Li dendrites and sluggish interfacial Li+ transfer dynamics between the Li metal and HSEs restrict practical applications. Herein, a facile strategy is proposed to promote homogeneous interfacial Li+ migration by modifying HSEs by using nitrogen plasma. N2 plasma not only decreases the crystallinity and glass transition temperature of HSE but also in‐situ generates an ultra‐stable and conductive Li3N layer on the HSE surface. This conductive layer promotes interfacial Li+ migration and favorable wettability, thus effectively improving Li+ transfer dynamics and homogeneous deposition. Therefore, a HSE modified by N2 plasma for 10 s exhibits a low interfacial impedance of 26.5 Ω cm−2 and a high Li+ conductivity of 7.35 × 10−5 S cm−1 at 30 °C. Moreover, a symmetric Li|HSE|Li battery exhibits a stable plating/stripping capability without Li dendrite growth at a current density of 0.1 mA cm−2 during continuous operation over 1000 h. In addition, an all‐solid‐state Li|HSE|LiFePO4 battery exhibits an initial specific capacity of 145.0 mAh g−1 at 1 C with a high capacity retention of 92.4% (134.0 mAh g−1) after 140 cycles.

In this study, with the assistance of quaternary ammonium salts we have successfully prepared a new family of salicylate-stabilized heterobimetallic Pb-Ti-oxo clusters, including H(TEA)[Pb2Ti6(μ2-O)2(μ3-O)2(OiPr)4(PA)2(Sal)6(NO3)2] (PTC-321; TEA = tetraethylammonium; HOiPr = isopropanol; H2PA = phenylphosphonic acid; H2Sal = salicylic acid), {PbTi3(μ2-O)(μ3-O)(OiPr)2(PA)(Sal)3(DMF)·CH3CN}n (PTC-322; DMF = dimethylformamide), {PbTi5(μ3-O)6(Sal)3(CH3COO)2(DMF)(OiPr)2}n (PTC-323), [Pb2Ti4(Sal)6(EtO)2(OiPr)6(HOiPr)2]·CH3NH2 (PTC-324; EtOH = CH3CH2OH), H[Pb4Ti9(μ2-O)2(μ3-O)(μ4-O)6(Sal)7(OiPr)13] (PTC-325), and Pb2Ti12(μ2-O)3(μ3-O)3(μ4-O)4(Sal)4(OEt)24 (PTC-326). Single-crystal X-ray diffraction studies demonstrate that the {Ti3Pb(Sal)3} unit acts as the building block to constitute the diverse assembly of PTC-321-PTC-323. Thereinto, the clusters in PTC-322 and PTC-323 are connected into infinite one-dimensional chains. Furthermore, the solvent effects have facilitated the heterobimetallic Pb-Ti-oxo clusters into various configurations in PTC-323-PTC-326. Solid-state ultraviolet-visible spectroscopy analysis indicates that the optical absorption bands of these compounds shift effectively toward the visible-light region, and they were also employed as electrode precursors to investigate their visible-light-driven photocurrent response.

As the quantity of waste tires increases, more pyrolysis carbon black(CBp), a type of low value-added carbon black, is being produced. However, the application of CBp has been limited. Therefore, it is necessary to identify and expand applications of CBp. This work focuses on the preparation of activated carbon(AC) from CBp using the physicochemical activation of carbon dioxide(CO 2 ) and potassium hydroxide(KOH). Thereafter, AC is applied to the electrode of the electrical double-layer capacitor(EDLC). The AC prepared by CO 2 /KOH activation exhibited a hierarchical pore structure. The specific surface area increased from 415 to 733 m 2 g -1 , and in combination with low ash content of 1.51%, ensured abundant ion diffusion channels and active sites to store charge. The EDLC comprising the AC(AC-2) electrode prepared by excitation of CO 2 (300 sccm) and KOH had a reasonable gravimetric specific capacitance of 192 F g -1 at 0.5 A g -1 , and exhibited a good rate capability of 73% at 50 A g -1 in a three-electrode system. Moreover, the EDLC device comprising the AC-2 electrode delivered excellent cycling stability(capacitance retention of 106% after 10000 cycles at 2 A g -1 in a two-electrode system). Furthermore, a symmetric supercapacitor based on an AC electrode that exhibits a supreme energy density of 4.7 Wh kg -1 and a maximum power density of 6362.6 W kg -1 is demonstrated.

Designing catalytic cathodes with excellent electrocatalytic activities and durability for Na-CO2 batteries has captured considerable attention so far. Here, a series of morphologically controlled low-crystalline CuCo2O4 was prepared by thermal oxidation of self-assembled Cu-Co precursors (p-CCO). One-dimensional (1D) rod-like of CuCo2O4 was subsequently encapsulated in polypyrrole shell (PPy) by in-situ polymerization of pyrrole monomers as an advanced catalyst (CCO/PPy) for high-performance Na-CO2 batteries. It was demonstrated that ammonia solution exerts an important influence on the surface morphology and size of the p-CCO crystallites by the rate of nucleation and growth. Particle size and 1D architecture modulation, associated with the encapsulation of conductive PPy effectively improve the directional transfer rate of ions and the conductivity of the electrode. More importantly, PPy introduction not only induces interfacial reconstruction of CuCo2O4, arousing more oxygen vacancies and catalytic active sites, but also contributes to the corrosion protection of the active material from the electrolyte during long-term operation. Bestowed by these advantages, the fabricated hybrid Na-CO2 battery manifested prominent electrochemical performance with a superior areal discharge capacity of 31.3 mAh cm-2, low discharge-charge voltage gap of 0.6 V, over 400 cycles.

As an important refractory metal, tungsten (W) has unique physical-chemical properties, and the applications of high-quality tungsten NPs with uniform particle size, high purity, and good particle dispersion in industrial fields are highly desirable. Herein, the integration of tungsten metallurgical purification and nanoparticle preparation is achieved by the hydrogen arc plasma method. In the process of purification, on the condition of arc current of 250 A, hydrogen concentrations of 30 vol%, purification time of 40 min, and gas pressure of 60 kPa, the highest impurity removal rate is achieved. The active H+ is able to react with impurities to generate metal hydride (MH, M = Al, Cr, Mg, and Fe), which promotes the removal rate of impurity elements. During the preparation of nanoparticles (NPs), the as-prepared tungsten NPs with an average particle size of 44.1 nm have a regular spherical structure, high purity, and a relatively uniform particle size distribution. When the hydrogen con-centration is controlled at 50 vol%, the extremely high temperature promotes the evaporation of tungsten. Meanwhile, the active H+ reacts with tungsten to form tungsten hydride (WH), further increasing the evapo-ration rate of tungsten. According to the above results, the hydrogen arc plasma promotes the simplification of the production process steps of high purity tungsten NPs and reduces the industrialized production cost of high-quality refractory metal NPs.

Developing low-cost, efficient electrocatalysts for the air electrode of high-performance rechargeable hybrid sodium-air batteries (HSABs) remains challenging. Herein, efficient bimetallic nanoparticles encapsulated in nitrogen-doped carbon (Co-Fe@NC) were developed for the oxygen reduction and evolution reactions in HSABs. The bimetallic Co-Fc@NC catalyst outperformed its monometallic counterparts in the oxygen reduction reaction (ORR)/oxygen evolution reaction (OER) activity. The assembled HSAB, utilizing the Co-Fe@NC in the air electrode, exhibited a smaller voltage gap of 0.27 V and a higher power density of 5.39 mW/cm(2) compared with the air electrode utilizing Pt/C + RuO2 (0.55 V, 4.79 mW/cm(2)). Furthermore, the round-trip efficiency of the assembled HSAB is up to 75.37% after 700 h of cycling at 0.1 mA/cm(2), outperforming the benchmark HSAB with Pt/C + RuO2 (65.76% after 400 h). This work presents a promising strategy to prepare low-cost, efficient electrocatalysts to substitute the precious catalyst Pt/C + RuO2 in HSABs or other metal-air batteries for practical applications.

Nickel cobalt phosphide (NiCoP) is emerging as a potential electrocatalyst towards oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). However, its ORR/OER activities are sluggish. Here, we investigated the roles of iron dopants in the Fe-doped NiCoP (Fe-NiCoP) in order to boost its ORR/OER kinetics. The density functional theory (DFT) calculations reveal that the Fe dopant effectively modulates the electron conductivity of NiCoP and reduces binding energies of the reaction intermediates towards rate-determining steps of ORR and OER. A binder-free 3D microflowers morphology of the Fe-NiCoP embedded in the amorphous carbon layer (Fe-NiCoP@C) catalyst on the nickel foam was prepared as the air cathode for the hybrid sodium-air battery (HSAB). The HSAB displays a discharge voltage of 2.74 V at 0.01 mA cm(-2) with excellent round trip efficiency of 93.26 % at the 500th cycle and state-of-the-art power density of 621 mW g(-1).

Significant challenges remain for developing efficient catalysts in an electrochemical multielectron CO2 reduction reaction (CO2RR), which usually suffers from poor activity and selectivity. Motivated by the recent experimental progress in fabricating dual-metal atom catalysts (DMACs) in N-doped graphene materials (graphene-N6V4; N: nitrogen and V: vacancy), we sampled eight types of homonuclear (N6V4-M-2, M = Cr, Mn, Fe, Co, Ni, Cu, Pd, and Ag) catalysts and 28 types of heteronuclear (N6V4-M1M2) catalysts to study CO2RR activity via first-principles high-throughput screening. Using stability, activity, and selectivity as indicators along with the broken conventional scaling relationship, N6V4-AgCr was selected as a promising candidate for deep CO2 reduction to methane with a low overpotential of 0.55 V after two screening rounds. Further analysis showed that a frustrated Lewis pair, formed between metal and the para-N, owing to the difference in the electronic arrangement of the d orbitals of various transition metals, caused a difference in the spin polarization of the systems and affected the catalytic performance of each DMAC. Our work not only provides a solid strategy for screening potential catalysts but also demonstrates that their CO2 reduction activities originate from the various atomic and electronic structures of DMACs.

We investigated the hydrolysis of TiIV along with naturally abundant AlIII ions and reported the formation of a stable and semiconducting nanocluster. Interestingly, this compound exhibits an unusual odd-membered ring structure and also represents the largest Al-containing polyoxotitanium cluster (PTC) observed thus far. The presence of a shell of organic ligands as well as the incorporation of hetero-AlIII ions endowed the nanocluster with high air, thermal, and pH stabilities. The present compound exhibited a record photocatalytic hydrogen evolution of 402.88 μmol g−1 h−1 among PTC materials. This work not only paves the way towards stable PTC materials but also provides new insights into the design of novel photocatalysts.

High-performance and low-cost catalysts are particularly desirable for the exploitation of practical low-overpotential Na-CO2 batteries with protracted cyclability. Herein, a well-defined morphology of nitrogen-rich graphitic carbon frameworks with dense bimetallic active sites (Fe-Cu-N-C) was facilely prepared by introducing Fe3+ and Cu2+ to regulate in situ grown carbon nanotubes as an advanced catalyst toward hybrid Na-CO2 batteries. Through metal content tuning and carbon architecture altering, Fe-Cu-N-C proved to be dramatically more effective than Cu-N-C and Fe-N-C. As the cathodic catalyst of a hybrid Na-CO2 battery, Fe-Cu-N-C can facilitate the fast evolution and degradation of flocculent discharge products and achieve an excellent long-term cyclability with up to 1550 cycles (over 600 h), which makes it one of the greatest catalysts for hybrid Na-CO2/air batteries that have been reported to date. The observed outstanding battery performance is attributable to the cross-linked conductive framework affording a "highway" for accelerated electron transport and Na+/CO2 diffusion. Besides, the synergistic effects among defect-rich interfaces, Fe/Fe3C nanocrystals, and Fe-N-x and Cu-N-x sites derived from nitrogen atom doping enhance the catalytic activity. In addition, the possible growth and decomposition mechanisms of NaHCO3 products with different morphologies on Fe-N-C, Cu-N-C, and Fe-Cu-N-C electrodes were presented and discussed.

The aqueous solution chemistry of Al(III) is an important subject in the fields of environmental chemistry, geochemistry and coordination chemistry. However, aluminum oxo clusters were generally isolated by the onestep synthesis method. In this paper, we developed a stepwise assembly synthesis strategy and successfully prepared two heterometallic aluminum oxo clusters. [Al4(L)4(Cat)2]center dot 2[Zn(Im)4]center dot 2Im (AlOC-121, H3L = 2,3-dihydroxybenzoic acid, Cat = catechol Im = imidazole) and [Al4(L)4(Cat)2]center dot 2[Fe(Im)6]center dot 2Im (AlOC-122). Single crystal structure analysis shows that they are unprecedented structure types, where aluminum oxo cluster precursor, metal complexes and guests co-crystallizing in one structure. These compounds were fully characterized and magnetic properties were also studied.

High-performance and low-cost catalysts are particularly desirable for the exploitation of practical low-overpotential Na-CO2 batteries with protracted cyclability. Herein, a well-defined morphology of nitrogen-rich graphitic carbon framework with dense bimetallic...