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Hydrogen peroxide (H2O2) is widely used as a green oxidant for varying applications. Electrosynthesis is an economical and environmentally-friendly strategy to directly produce H2O2. Its practical production is hindered, however, by the lack of highly efficient and selective as well as low-cost electrocatalysts. Transition metal chalcogenide materials have been proved to be good catalysts for the oxygen evolution reaction, but their selectivity towards conversion of O2 to H2O2 remains unsatisfactory. In this work, 3 atomic-layer defect-rich CoSe2 nanosheets have been successfully grown on carbon cloth as a high performance electrocatalyst. The morphology of CoSe2 can be tuned by regulating the wettability of the growth substrate. The atomic-layer CoSe2 nanosheets showed unprecedented 92% selectivity towards H2O2 production in alkaline solutions, and the yields of H2O2 in alkaline and acidic solutions were 1227.7 mg L−1 h−1 and 894 mg L−1 h−1, respectively. The high efficiency and selectivity originate from the rich defects in the atomic-layer CoSe2 nanosheets, which can accelerate the adsorption of OOH by the exposed Co defect sites.

Metal–organic frameworks (MOFs) are increasingly being investigated as electrocatalysts for the oxygen evolution reaction (OER). Despite their promising catalytic activity, many fundamental questions concerning their structure−performance relationships—especially those regarding the roles of active species—remain to be answered. Here we show the structural transformation of a Ni0.5Co0.5-MOF-74 during the OER by operando X-ray absorption spectroscopy analysis and high-resolution transmission electron microscopy imaging. We suggest that Ni0.5Co0.5OOH0.75, with abundant oxygen vacancies and high oxidation states, forms in situ and is responsible for the high OER activity observed. The ratio of Ni to Co in the bimetallic centres alters the geometric and electronic structure of as-formed active species and in turn the catalytic activity. Based on our understanding of this system, we fabricate a Ni0.9Fe0.1-MOF that delivers low overpotentials of 198 mV and 231 mV at 10 mA cm−2 and 20 mA cm−2, respectively. Metal–organic frameworks (MOFs) are increasingly being explored for electrocatalytic oxygen evolution, which is half of the water splitting reaction. Here the authors show that, under reaction conditions, mixed metal oxyhydroxides form at the nodes of bimetallic MOFs, which are highly catalytically active.

BackgroundIntravenous immunoglobulin (IVIG) showed its therapeutic efficacy on Kawasaki disease (KD). However, the mechanisms by which it reduces systemic inflammation are not completely understood. Dendritic cells (DCs) and T cells play critical roles in the pathogenic processes of immune disorders. Assessing the quantity of DC subsets and T cells and identifying functional molecules present on these cells, which provide information about KD, in the peripheral blood may provide new insights into the mechanisms of immunoglobulin therapy.MethodsIn total, 54 patients with KD and 27 age-matched healthy controls (HCs) were included in this study. The number, percentage, and phenotype of DC subsets and CD4+ T cells in peripheral blood were analyzed through flow cytometry.ResultsPatients with KD exhibited fewer peripheral DC subsets and CD4+ T cells than HCs. Human leucocyte antigen-DR (HLA-DR) expression was reduced on CD1c+ myeloid DCs (CD1c+ mDCs), whereas that on plasmacytoid DCs (pDCs) did not change significantly. Both pDCs and CD1c+ mDCs displayed significantly reduced expression of co-stimulatory molecules, including CD40, CD86. pDCs and CD1c+ mDCs presented an immature or tolerant phenotype in acute stages of KD. Number of circulating pDC and CD1c+ mDC significantly inversely correlated with plasma interleukin-6 (IL-6) levels in KD patients pre-IVIG treatment. No significant differences were found concerning the DC subsets and CD4+ T cells in patients with KD with and without coronary artery lesions. Importantly, these altered quantity and phenotypes on DC subsets and CD4+ T cells were restored to a great extent post-IVIG treatment. T helper (Th) subsets including Th1 and Th2 among CD4+ T cells did not show alteration pre- and post-IVIG treatment, although the Th1-related cytokine IFN-γ level in plasma increased dramatically in patients with KD pre-IVIG treatment.ConclusionspDCs and CD1c+ mDCs presented an immature or tolerant phenotype in acute stages of KD, IVIG treatment restored the quantity and functional molecules of DCs and CD4+ T cells to distinct levels in vivo, indicating the involvement of DCs and CD4+ T cells in the inflammation in KD. The findings provide insights into the immunomodulatory actions of IVIG in KD.

To reach a closed-loop material system and meet the urgent requirement of sustainable energy storage technologies, it is essential to incorporate efficient waste management into designing new energy storage materials. Here, a “two birds with one stone” strategy to transform rusty iron products into Prussian blue as high-performance cathode materials, and recover the rusty iron products to their original status, is reported. Owing to the high crystalline and Na+ content, the rusty iron derived Prussian blue shows a high specific capacity of 145 mAh g−1 and excellent cycling stability over 3500 cycles. Through the in situ X-ray diffraction and in situ Raman spectra, it is found that the impressive ion storage capability and stability are strongly related to the suppressed structure distortion during the charge/discharge process. The ion migration mechanism and the possibility to serve as a universal host for other kinds of ions are further illuminated by density functional theory calculations. This work provides a new strategy for recycling wasted materials into high value-added materials for sustainable battery systems, and is adaptable in the nanomedicine, catalysis, sensors, and gas storage applications.

Intravenous immunoglobulin (IVIG) showed its therapeutic efficacy on Kawasaki disease (KD). However, the mechanisms by which it reduces systemic inflammation are not completely understood. Dendritic cells (DCs) and T cells play critical roles in the pathogenic processes of immune disorders. Assessing the quantity of DC subsets and T cells and identifying functional molecules present on these cells, which provide information about KD, in the peripheral blood may provide new insights into the mechanisms of immunoglobulin therapy.In total, 54 patients with KD and 27 age-matched healthy controls (HCs) were included in this study. The number, percentage, and phenotype of DC subsets and CD4Patients with KD exhibited fewer peripheral DC subsets and CD4pDCs and CD1c

Summary Room-temperature sodium-sulfur batteries have significant potential for large-scale applications due to the low cost and high energy density of both sulfur and sodium. Nevertheless, the insulating nature of sulfur and the shuttle effect are impeding their practical application. Here we report that dispersed single-atom Fe sites anchored on a nitrogen-doped carbon matrix present an atomic-level strategy for the development of sulfur hosts. The electronic structure of sulfur is modified by the atomically dispersed Fe-N4 sites, which can transfer the electron to sulfur, thereby enhancing its reactivity. The S@Fe1-NMC cathode delivers a high reversible capacity of 1,650 mAh g−1 initially and 540 mAh g−1 after 500 cycles at 100 mA g−1. A dual function mechanism is observed on S-Fe-N4 sites, which can activate the polysulfides by weakening the S-S bonds and accelerate Na+ diffusion into Na-poor regions to engender a high driving force for Na2Sx decomposition, thus inhibiting the shuttle effect.

Both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) are crucial to water splitting, but require alternative active sites. Now, a general π-electron-assisted strategy to anchor single-atom sites (M=Ir, Pt, Ru, Pd, Fe, Ni) on a heterogeneous support is reported. The M atoms can simultaneously anchor on two distinct domains of the hybrid support, four-fold N/C atoms (M@NC), and centers of Co octahedra (M@Co), which are expected to serve as bifunctional electrocatalysts towards the HER and the OER. The Ir catalyst exhibits the best water-splitting performance, showing a low applied potential of 1.603 V to achieve 10 mA cm in 1.0 m KOH solution with cycling over 5 h. DFT calculations indicate that the Ir@Co (Ir) sites can accelerate the OER, while the Ir@NC sites are responsible for the enhanced HER, clarifying the unprecedented performance of this bifunctional catalyst towards full water splitting.

Symmetric full-cells, which employ two identical electrodes as both the cathode and anode, attract great research attention, because it has high safety, facial fabrication and lower costs. Unfortunately, the practical utilization of full symmetric energy storage systems, especially the symmetric potassium ion batteries (KIBs), is hindered by the limited choice of the available electrode materials. In this work, a novel NASICON-type K 3 V 2 (PO 4 ) 3 is prepared and first employed for the symmetric KIBs. Through in-situ measurement, a highly lattice reversibility is found during the K + insertion/extraction process. KV 2 (PO 4 ) 3 and K 5 V 2 (PO 4 ) 3 was generated after the depotassiation and potassiation process at about 4.0 V and below 1.0 V, respectively. The reversible capacity of the full symmetric KIBs is about 90 mAh g −1 between 0.01 and 3.0 V at 25 mA g −1 , corresponding to an initial coulombic efficiency of 91.7% which is the highest one among all the previous reported symmetric energy storage systems (including the symmetric lithium/sodium ion batteries). 88.6% reversible capacity was maintained even after 500 cycling test. More importantly, a largest working potential at about 2.3 V was obtained in this work, benefiting the output energy of this symmetric energy storage system. The outstanding cycling stability, large working potential and the highest initial coulombic efficiency endow this work with promising advantages for the future development of the novel energy storage system.

Room-temperature sodium-sulfur (RT-Na/S) batteries hold significant promise for large-scale application because of low cost of both sodium and sulfur. However, the dissolution of polysulfides into the electrolyte limits practical application. Now, the design and testing of a new class of sulfur hosts as transition-metal (Fe, Cu, and Ni) nanoclusters (ca. 1.2 nm) wreathed on hollow carbon nanospheres (S@M-HC) for RT-Na/S batteries is reported. A chemical couple between the metal nanoclusters and sulfur is hypothesized to assist in immobilization of sulfur and to enhance conductivity and activity. S@Fe-HC exhibited an unprecedented reversible capacity of 394 mAh g-1 despite 1000 cycles at 100 mA g-1 , together with a rate capability of 220 mAh g-1 at a high current density of 5 A g-1 . DFT calculations underscore that these metal nanoclusters serve as electrocatalysts to rapidly reduce Na2 S4 into short-chain sulfides and thereby obviate the shuttle effect.

The ethanol oxidation reaction is extensively explored, but electrocatalysts that could achieve a complete oxidation pathway to CO2/CO32− are much less reported. Here, we synthesize a monatomic Pt layer (Pt-skin) on ordered intermetallic PtBi clusters (PtBi@Pt) supported on graphene via a single atom self-assembling (SAS) method to form a superior catalyst. The PtBi@Pt with an ultrafine size (∼2 nm) delivers an extremely high mass activity of 9.01 mA μgPt−1, which is 8-fold more active than the commercial Pt/C; significantly, in situ Fourier transform infrared spectroscopy indicates that ethanol is completely oxidized to CO32− on the PtBi@Pt, accompanied by 12 electron transfer, as is further demonstrated by the density functional theory results.

Highlights A new heteronuclear bi-atom electrocatalyst has been proposed by Ma and his co-workers. The FeV@C2N bi-atom electrocatalyst achieved excellent electrochemical NRR performance. The FeV@C2N bi-atom electrocatalyst could effectively suppress the side and competing HER reaction, and thus possess better electrochemical NRR selectivity., The electrochemical nitrogen reduction reaction (NRR) to directly produce NH3 from N2 and H2O under ambient conditions has attracted significant attention due to its ecofriendliness. Nevertheless, the electrochemical NRR presents several practical challenges, including sluggish reaction and low selectivity. Here, bi-atom catalysts have been proposed to achieve excellent activity and high selectivity toward the electrochemical NRR by Ma and his co-workers. It could accelerate the kinetics of N2-to-NH3 electrochemical conversion and possess better electrochemical NRR selectivity. This work sheds light on the introduction of bi-atom catalysts to enhance the performance of the electrochemical NRR.

To reach a closed-loop material system and meet the urgent requirement of sustainable energy storage technologies, it is essential to incorporate efficient waste management into designing new energy storage materials. Here, we reported a “two birds with one stone” strategy to transform rusty iron products into Prussian blue as high-performance cathode materials and recover the rusty iron products to their original status. Owing to the high crystalline and Na+ content, the rusty iron derived Prussian blue shows a high specific capacity of 145 mAh g− 1 and excellent cycling stability over 3500 cycles. Through the in situ X-ray diffraction and in situ Raman spectra, it is found that the impressive ion storage capability and stability are greatly related to the suppressed structure distortion during the charge/discharge process. The ions migration mechanism and possibility as universal host of other kinds of ions are further illuminated by density functional theory calculations. This work provides a new strategy for recycling wasted materials into high value-added materials for sustainable battery systems, and is adaptable in the nanomedicine, catalysis, sensors, and gas storage applications.

In order to solve the problems of slope strength reduction and stability risks caused by excessive surface water in mountain tunnels, the influence of surface pore water on slope stability is deeply studied. This article first analyzes the seepage field of unsaturated soil. Taking the transient seepage field as the object, the distribution of the soil seepage field during the two-stage precipitation process is studied. Secondly, the existing dimensionless second-order partial differential equation is solved by Laplace transform to calculate the distribution of transient seepage field. A finite element model of rock and soil seepage field under different rainfall intensities was established, and the influence of pore water content on slope stability was quantitatively analyzed. The results show that as the anti-sliding force decreases, the pore water content increases, the pressure increases, the suction force of the matrix decreases, the shear strength decreases, and the slope safety factor decreases, which leads to the plastic deformation of the slope.

All‐solid‐state sodium batteries (ASSBs) are regarded as the next generation of sustainable energy storage systems due to the advantages of abundant sodium resources, and their exceptional and high energy density. Nevertheless, there are still grand challenges to realize their practical applications, such as the limited types of solid‐state electrolytes (SEs), low ionic conductivity of SEs, high charge‐transfer impedance, interfacial issues, and Na dendrite growth. Herein, the recent progress and challenges of various SEs for ASSBs are summarized, including solid polymer electrolytes, inorganic solid electrolytes (including oxides, sulfides, and boron hydrides), and their combinations. Furthermore, recent reports on various cathodes materials and corresponding cathode/SE interfacial issues are comprehensively reviewed. Current trends and future perspectives on sodium metal anodes are discussed in detail with an emphasis on the anode interface protection and innovative SEs with good Na compatibility. Finally, future opportunities for the development of ASSBs are outlined.

This work presents fundamental understanding of the correlation between nanoindentation hardness and practical scratch resistance for mechanically tunable anti-reflective (AR) hardcoatings. These coatings exhibit a unique design freedom, allowing quasi-continuous variation in the thickness of a central hardcoat layer in the multilayer design, with minimal impact on anti-reflective optical performance. This allows detailed study of anti-reflection coating durability based on variations in hardness vs. depth profiles, without the durability results being confounded by variations in optics. Finite element modeling is shown to be a useful tool for the design and analysis of hardness vs. depth profiles in these multilayer films. Using samples fabricated by reactive sputtering, nanoindentation hardness depth profiles were correlated with practical scratch resistance using three different scratch and abrasion test methods, simulating real world scratch events. Scratch depths from these experiments are shown to correlate to scratches observed in the field from consumer electronics devices with chemically strengthened glass covers. For high practical scratch resistance, coating designs with hardness &gt, 15 GPa maintained over depths of 200–800 nm were found to be particularly excellent, which is a substantially greater depth of high hardness than can be achieved using previously common AR coating designs.

Anti-reflection coatings are widely used throughout the field of optical technology such as in corrective eyeglasses, camera lenses, and microscope optics, to improve the transmittance and reduce the reflectance of glass and other transparent materials. To date, these coatings have suffered from relatively poor scratch resistance and high scratch visibility compared to standard glasses. This has limited their use in applications requiring high mechanical durability such as on the chemically strengthened glasses widely used in modern touch screen devices. Here extremely scratch-resistant anti-reflection coatings are fabricated using industrially scalable reactive sputtering processes. These coatings provide a combination of surface reflectance below 0.7%, low color shifts, nanoindentation hardness as high as 18 GPa, and levels of scratch resistance which dramatically exceed commercial chemically strengthened glasses. An interdisciplinary opto-mechanical design approach has enabled a significant paradigm shift in the use of high-precision optical coatings for mechanically demanding applications. As a direct outcome of the work reported in this Letter, similar coating designs have been successfully deployed on millions of consumer electronics devices with very robust field performance.

The low-cost room-temperature sodium-sulfur battery system is arousing extensive interest owing to its promise for large-scale applications. Although significant efforts have been made, resolving low sulfur reaction activity and severe polysulfide dissolution remains challenging. Here, a sulfur host comprised of atomic cobalt-decorated hollow carbon nanospheres is synthesized to enhance sulfur reactivity and to electrocatalytically reduce polysulfide into the final product, sodium sulfide. The constructed sulfur cathode delivers an initial reversible capacity of 1081 mA h g−1 with 64.7% sulfur utilization rate; significantly, the cell retained a high reversible capacity of 508 mA h g−1 at 100 mA g−1 after 600 cycles. An excellent rate capability is achieved with an average capacity of 220.3 mA h g−1 at the high current density of 5 A g−1. Moreover, the electrocatalytic effects of atomic cobalt are clearly evidenced by operando Raman spectroscopy, synchrotron X-ray diffraction, and density functional theory., Room-temperature sodium-sulfur batteries hold promise, but are hindered by low reversible capacity and fast capacity fade. Here the authors construct a multifunctional sulfur host comprised of cobalt-decorated carbon nanospheres that impart attractive performance as a cathode in a sodium sulfide battery.

“单原子层团簇”催化剂这一新概念, 不同于单原子催化剂和传统的纳米颗粒催化, 是由单原子建造新型的二维单原子层催化剂. 单原子层团簇催化剂的活性中心明确, 且原子间的相互作用会极大提高催化反应的选择性. 因此该催化剂材料不仅具有优异的催化性能, 还具有良好的选择性. 基于此, 作者同时分析和指出了未来的单原子层团簇催化剂的可能重点研究方向以及挑战.

Architectural control of porous solids, such as porous carbon cages, has received considerable attention for versatile applications because of their ability to interact with liquids and gases not only at the surface, but throughout the bulk. Herein we report a scalable, facile spray-pyrolysis route to synthesize holey carbon microcages with mosquito-net-like shells. Using the surfaces of water droplets as the growth templates, styrene-butadiene rubber macromolecules are controllably cross-linked, and size-controllable holes on the carbon shells are generated. The as-formed carbon microcages encapsulating Si nanoparticles exhibit enhanced lithium-storage performances for lithium-ion batteries. The scalable, inexpensive synthesis of porous carbon microcages with controlled porosity and the demonstration of outstanding electrochemical properties are expected to extend their uses in energy storage, molecular sieves, catalysis, adsorbents, water/air filters, and biomedical engineering.

Room-temperature sodium–sulfur batteries are competitive candidates for large-scale stationary energy storage because of their low price and high theoretical capacity. Herein, pure S nanosheet cathodes can be grown in situ on three-dimensional Cu foam substrate with the condensation between binary polymeric binders, serving as a model system to investigate the formation and electrochemical mechanism of unique S nanosheets on the Cu current collectors. On the basis of the confirmed conversion reactions to Na2S, The constructed cathode exhibits ultrahigh initial discharge/charge capacity of 3189/1403 mAh g–1. These results suggest that there is great potential to optimize S cathode by exploiting low-cost Cu substrates instead of conventional Al current collectors.

Improving the CO tolerance of Pt-based catalysts is very meaningful for the application in proton exchange membrane fuel cells and direct alcohol fuel cells. The behavior of Pt-based bimetallic catalysts is depended on their phase and surface composition. In this work, we tuned the surface composition of Pt3Co nanocatalysts by heat treatment under different atmosphere. The results of atomic-resolution HAADF-STEM, XRD, XPS and electrochemical characterization demonstrated that the surface composition of Pt3Co catalysts with Co-increased, Intermetallic and Pt-increased were obtained by metal segregation approach. Due to the differences in the surface atomic distribution and alloying extent, the nanocatalysts show different CO poisoning tolerance in the order of Co-increased>Intermetallic>Pt-increased. CO stripping voltammetry and in-situ Fourier transform infrared spectroscopy (FTIRS) were used together to investigate the origin of varied CO poisoning tolerance on three Pt3Co catalysts. The results illustrated that electronic effect plays a major role in weakening CO adsorption on Pt3Co nanocatalysts and thus promoting CO oxidation to form COOHad intermediate consistent with Langmuir-Hinselwood mechanism. Oxophilic effect promotes the oxidation of COOHad intermediate into the final products CO2/CO32-. This work provides a new insight into tuning phase and surface composition of catalysts thus enhancing CO tolerance of Pt-based bimetallic catalysts.

We report for the first time a facile preparation of double-shell pomegranate-like porous carbon microspheres (PCMs) by a modified templating technique. The microsized PCMs are encapsulated within integrated carbon coating layers and composed of interconnected nanosized hollow carbon spheres, giving rise to a special double-shell structure. Calcium carbonate (CaCO3) is employed as the primary sacrificial template and acetylene as the carbon precursor via chemical vapor deposition (CVD). The PCMs exhibit an initial coulombic efficiency of 91% and a reversible capacity of 650 mA h g−1 at a current density of 200 mA g−1 after 500 cycles. Moreover, PCMs show excellent rate capability with capacities of 580 and 520 mA h g−1 at current densities of 1000 and 2000 mA g−1, respectively. The outstanding electrochemical properties of PCMs are originated from their unique structure. The inner interconnected porous carbon framework encapsulated by a self-supporting outer carbon coating shell provides more lithium ion storage sites, high electronic conductivity and fast ion diffusion. Most importantly, different from the previous studies, the introduction of the carbon coating layers on the outer surface of the whole microsphere can effectively strengthen the mechanical properties and prevent the electrolyte ingress, limiting the formation of extra solid–electrolyte interface films.

In order to maximize the Pt utilization in catalysts and improve catalytic processes, we report a convenient strategy for preparation of Pt3Co with Pt-skin structured bimetallic nanocatalysts directly supported on porous graphitic carbon. Notably, the thickness of the Pt-skin is only 1–2 atomic layers, about 0.5 nm. Surprisingly, the bimetallic nanocatalysts composed of Pt3Co with Pt-skin are first used as ethanol electro-catalysts, with the mass activity of 0.79 mA μgPt–1, which is a 250% enhancement compared with commercial Pt/C (0.32 mA μgPt–1). On the basis of the results of electrochemical in situ Fourier transform infrared spectroscopy (FTIRS) and density functional theory (DFT), a new ethanol electro-oxidation enhancement mechanism is proposed in which Pt3Co with Pt-skin promotes partial oxidation of ethanol over C–C bond cleavage, thereby resulting in higher CH3COOH production than CO2 production.

Wavelength-selective coatings are broadly applied across diverse industries such as solar energy management, infrared sensing, telecommunications, laser optics, and eye-protective lenses. These coatings have historically not been optimized for hardness or mechanical durability and typically suffer from higher susceptibility to scratch and damage events than uncoated glass. In this work, we describe a family of wavelength-selective coatings with hardness and scratch resistance that are significantly higher than the chemically strengthened glass substrates on which the coatings are fabricated. The coatings are made using industrially scalable reactive sputtering methods. Wavelength-selective coatings are fabricated with nanoindentation hardness as high as 16&ndash, 20 GPa over indentation depths ranging from 200 to 800 nm, as well as excellent durability in aggressive scratch testing. Tunable visible to near-infrared wavelength selectivity ratios (reflectance of stopband: reflectance of passband) as high as 7:1 are achieved. The feasibility of narrowband hard coating design is also demonstrated, with visible narrowband transmission having a peak FWHM of ~8 nm (~1.6%). A unique &ldquo, buried layers&rdquo, hard coating design strategy is shown to deliver particularly excellent hardness profiles. These designs can be tailored for a variety of different wavelengths and selectivity ratios, enabling new uses of wavelength-selective optics in mechanically demanding applications.

A novel heterostructured Si@C@Ge anode is developed via a two-step sol–gel method. A facile and straightforward Ge decoration significantly boosts the Li-storage performance of core–shell Si@C nanoparticles on both mechanics and kinetics. The Si@C@Ge anode shows unprecedented electrochemical performance in terms of accessible capacity, cycling stability, and rate capability when compared to those of a core–shell Si@C anode. Based on the experimental results and analysis of the mechanism, it is evident that high-conductivity Ge nanograins on the surface facilitates the Li diffusivity and electron transport and guarantees high ion accessibility. Moreover, it is the Ge nanograins that serve as buffering cushion to tolerate the mechanic strain distribution on the electrode during lithiation/delithiation processes.

To explore the vertical bearing capacity of pile foundations in the loess area, relying on the new construction project, a single pile vertical compressive bearing capacity field test was conducted on three test piles, and the Q-S curve and S-lgt curve of the single pile vertical static load test The analysis and research showed that the axial force of the three test piles had not been transmitted to the pile end, and the load was mainly borne by the reaction force provided by the frictional resistance of the pile side. The distribution of the axial force of the pile with depth is not only related to the size of the pile top load, but the nature of the soil around the pile is related to the typical friction pile characteristics, and the Q-S curves all show a slow-change type with no obvious steep drop. When loading 4900kN, none of them reached the ultimate failure, and the settlements of the three trial-installed piles were 12.24, 15.44 and 18.64mm, respectively. By comparing the test results with the design requirements, the bearing capacity of the single pile meets the requirements, indicating that in the loess area, the single pile has a higher bearing capacity, and the settlement is more uniform and the settlement is small, which can be used as a building foundation to bear a larger load.

In recent years, loess geological disasters in Longdong region occurred more and more frequently. On the basis of investigation on loess geological disasters in Longdong region and analysis of basic physical characteristics of loess geological disasters, landslide, collapse, debris flow and loess collapsibility are identified as the main geological disasters in Longdong region. The causes of four types of loess geological disasters in Longdong region are studied and corresponding prevention measures are proposed.

Confinement of polysulfides in sulfur cathodes is pivotal for eliminating the "shuttle effect" in metal-sulfur batteries, which represent promising solutions for large-scale and sustainable energy storage. However, mechanistic exploration and in-depth understanding for the confinement of polysulfides remain limited. Consequently, it is a critical challenge to achieve highly stable metal-sulfur batteries. Here, based on a 2D metal-organic framework (2D MOF), a new mechanism to realize effective confinement of polysulfides is proposed. A combination of in situ synchrotron X-ray diffraction, electrochemical measurements, and theoretical computations reveal that the dynamic electron states of the Ni centers in the 2D MOF enable the interaction between polysulfides and the MOF in the discharge/charge process to be tuned, resulting in both strong adsorption and fast conversion kinetics of polysulfides. The resultant room-temperature sodium-sulfur batteries are amongst the most stable reported so far, thus demonstrating that the new mechanism opens a promising avenue for the development of high-performance metal-sulfur batteries.

Symmetric full-cells, which employ two identical electrodes as both the cathode and anode, attract great research attention, because it has high level of safety, facial practical fabrication process and lower manufacturing costs. Unfortunately, the practical utilization of full symmetric energy storage systems, especially the symmetric potassium ion batteries (KIBs), is hindered by the limited choice of the available electrode materials. In this work, a novel NASICON-type K3V2(PO4)3 is prepared and first employed for the symmetric KIBs. Through in-situ measurement, a highly lattice reversibility is found during the K+ insertion/extraction process. KV2(PO4)3 and K5V2(PO4)3 was generated after the depotassiation and potassiation process at about 4.0 V and below 1.0 V, respectively. The reversible capacity of the full symmetric KIBs is about 90 mAh g-1 between 0.01–3.0 V at 25 mA g-1, corresponding to an initial coulombic efficiency of 91.7 % which is the highest one among all the previous reported symmetric energy storage systems (including the symmetric lithium/sodium ion batteries). 88.6 % reversible capacity was maintained even after 500 cycling test. More importantly, a largest working potential at about 2.3 V was obtained in this work, benefiting the output energy of this symmetric energy storage system. The outstanding cycling stability, large working potential and the highest initial coulombic efficiency endow this work with promising advantages for the future development of the novel energy storage system.

Uniform CeO 2 nanorods (CeO 2 -r) and CeO 2 nanoparticles (CeO 2 -p) are synthesized by hydrothermal method and are used as supports to load Pt nanoparticles (indexed as Pt/CeO 2 -r & Pt/CeO 2 -p) for methanol electrooxidation. HRTEM images indicate that the synthesized CeO 2 -r are covered by (1 0 0) and (1 1 0) facets which own higher surface energy compared to CeO 2 -p with (1 1 1) facets. Electrochemical characterizations demonstrate Pt/CeO 2 -r shows excellent specific activity which is 1.6 and 10 times higher than Pt/CeO 2 -p and commercial Pt/C (indexed as Pt/C-JM) towards electrooxidation of methanol. By in-situ FTIR spectroscopic investigation, much higher CO 2 productivity is observed at low potential on Pt/CeO 2 -r that implies strong anti-poisoning ability during methanol electrooxidation. The significant improved electrocatalytical performance is attributed to the existence of CeO 2 nanorods with high energy surfaces.

Well-dispersed PtBi intermetallic and PtBi intermetallic with Bi-rich surface supported on the porous graphitic carbon have been synthesized by using hydrogen gas to reduce the Pt and Bi precursors. TEM images indicated that the simple and clean method can effectively synthesize those PtBi intermetallics with uniform dispersion and small size (below 3 nm) on the porous graphitic carbon. Electrochemical characterization revealed that PtBi intermetallic with Bi-rich surface showed extremely high mass activity and stability towards oxidizing of formic acid. Combining precursors’ melt-diffusion strategy with the following effective reduction by the hydrogen gas, the proposed method is easy to scale up and has promising potential for synthesizing anode electro-catalyst of direct formic acid fuel cells.

The high-index facets of face-centered cubic metal have high surface energy, and the thermodynamics of crystal growth makes the high-index facets disappear during the crystal growth. The surface energy of high-index facets can be reduced through adsorption of molecules during crystal growth, and metal nanoparticles with high-index facets are thus formed. The shape-controlled synthesis of metal nanocrystals remains a big challenge even today. The shape evolution mechanism of metal nanocrystals with different facets has not yet been well elucidated. In this work, platinum nanocrystals of different shapes, octahedra with low-index facets, tetrahexahedra and concave hexoctahedron enclosed with high-index facets, were synthesized by the square-wave-potential method (SWP). The same precursor and the same adsorption molecules were used to synthesize Pt nanocrystals, but a series of parameter were varied, such as precursor concentration, growth potential, oxidative etching potential, with/without electrolyte in solution, and frequency of the SWP. This paper discusses the details about shape-controlled synthesis and proposes the preliminary mechanism of formation of Pt nanocrystals. The current study has illustrated that the electrochemical approach is an effective and facile route in tuning Pt nanocrystals’ shape and corresponding properties, shedding lights on the design and preparation of Pt nanocatalysts.

Uniform densification of relatively thick (~7 mm) consolidated boron carbide plates at relatively low temperatures (e.g. 1800°C) and low facture toughness are two of the primary challenges for further development of boron carbide applications. This work reports that these two challenges can be overcome simultaneously by adding 5 wt% alumina as a sintering aid. Nearly fully dense (97%), fine grained boron carbide (B4C) samples were produced using spark plasma sintering at 1700°C and above in the B4C-5 wt% Al2O3 system. The alumina and boron carbide matrix reacted to form an Al5O6BO3 (a mullite-like phase) during sintering. The Al5O6BO3 phase facilitated uniform densification via liquid phase sintering. This secondary phase is dispersed throughout the intergranular pores, providing obstacles for crack propagation and resulting in tougher boron carbide ceramics.

Water resources are the key factors that restrict the development of Qingyang Longdong energy and chemical industry base. Taking Qingyang Longdong energy and chemical industry base as an example, this paper takes the status quo of water resources as the research object, and points out the problems existing in the current situation of water resources development based on the current status of water quality research and utilization, and then puts forward corresponding measures to promote the sustainable use of water resources. The research results can provide reference for the vigorous construction of Qingyang energy and chemical industry base and the sustainable use and development of local water resources.

Bin-Wei Zhang, Yan Jiao, Dong-Liang Chao, Chao Ye, Yun-Xiao Wang, Kenneth Davey, Hua-Kun Liu, Shi-Xue Dou, and Shi-Zhang Qiao

The identification of rate-determining step (RDS) is vital for understanding reaction mechanisms and designing advanced catalysts. Here, we systemically studied the H–D kinetic isotope effects (KIEs) on electrooxidation of ethanol, isopropanol, and ethylene glycol (EG) on Au, Pd and Pt electrodes in alkaline solution by combining cyclic voltammetry and in situ FTIR spectroscopy. Large primary KIEs are observed on Au electrode: 8.4 for ethanol, 6.2 for EG and 7.9 for isopropanol when α-H of alcohols are substituted by deuterium, but much lower KIEs (

Rechargeable sodium-ion batteries are proposed as the most appropriate alternative to lithium batteries due to the fast consumption of the limited lithium resources. Due to their improved safety, polyanion framework compounds have recently gained attention as potential candidates. With the earth-abundant element Fe being the redox center, the uniform carbon-coated Na

Bimetallic PtPb nanodendrites with a single-crystalline structure were obtained by a facile one-pot strategy. The as-synthesized dendritic structure was well characterized and the growth mechanism was investigated. PtPb nanodendrites exhibited superior activity (5.1 times higher than commercial Pd black) and strong anti-poisoning ability for electrooxidation of formic acid.

TSZ-6A type strain control triaxial compression apparatus is applied for indoor test of some soil samples in Gansu Longdong (Qingyang) loess landslide, unconfined shear test of undisturbed soil samples, and the loading and unloading test of loess remodeling. The influences of different moisture content and confining pressure and the initial stress field on loess strength are considered respectively. Mechanical properties of loess in the state of loading and unloading state are compared and the corresponding q-e curves are drawn. The test shows that loess strength has a lot of structural characteristics, and loess structural damage has great impact on its strength. At the same time, the loess strength has important connection with its moisture content, stress state and stress path.