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Developing low-cost and highly efficient oxygen evolution reaction (OER) and urea oxidation reaction (UOR) electrocatalysts is critically important for hydrogen production through electrochemical water splitting.

Developing economic and acid-compatible oxygen evolution electrocatalysts is vital for their practical application in proton exchange membrane water electrolyzers, which has drawn worldwide attention.

Accurate identification of natural and mine earthquakes in mining areas is of great significance to the construction of secondary disaster warning networks. Based on 490 records of natural and mine earthquakes in the Hegang area from 2006 to 2017, this paper compares and analyzes the ground motion characteristics of the research samples (150 earthquake records and 200 mine earthquake records) and selects the key identification parameters of dominant frequency, Pm/Tc, and Sm/Tc. The correct identification rate of the test samples (60 seismic records and 80 mine earthquake records) is 95.7%, 91.4%, and 93.6%, respectively, and the actual threat rate is 90.8%, 83.3%, and 86.3%, respectively. Finally, based on the selected key identification parameters, a “three-parameter comprehensive gradient discriminant method” is proposed. The correct identification rate and actual threat rate are 99.3% and 98.4%, respectively, which can basically accurately identify natural and mine earthquakes. It provides a certain method and theoretical support for the mining area vibration identification method, safety production, and disaster warning.

Freeze-thaw seriously deteriorates the engineering properties of roadbed soil, and it will adversely affect the performance and service life of roads in seasonally frozen regions. Freeze-thaw and triaxial tests were conducted on a kind of roadbed clay to characterize the change rules of failure strength, cohesion, and friction angle under controlled thawing time, freezing temperature, moisture content, compaction degree, and numbers of freeze-thaw cycle. The thawed specimens had the weakest mechanical properties after thawing 2 h. Failure strength and cohesion of the freeze-thaw soil decreased considerably with the dropped freezing temperature, increasing moisture content, and improved compaction degree. The change in friction angle was less remarkable and exhibited an opposite trend with the freezing temperature and compaction degree. There was a great reduction in failure strength and cohesion after the first few cycles of freeze-thaw, and then a plateau was reached, whereas the friction angle decreased after one to two cycles and then recovered to a value higher than that of the unfrozen soil. The results demonstrated that the combined action of different factors should be considered to better understand the deterioration effect of freeze-thaw cycles under unfavorable conditions.

Developing efficient hydrogen oxidation reaction (HOR) electrocatalysts in alkaline media is of great significance for anion exchange membrane fuel cells. Herein, we report the synthesis of hollow colloidosomes composed of Ru nanocrystals based on a novel gas/liquid interface self-assembly strategy. Structural characterizations reveal that much defects are present in the building block (Ru nanocrystals) of Ru colloidosomes. Theoretical calculations suggest that the defects in the Ru structure can optimize the adsorption binding energy of reaction intermediates for the HOR. Benefiting from the assembled colloidosome and optimized electronic structure, the Ru colloidosomes exhibit remarkable HOR catalytic performance in alkaline media with a mass activity higher than that of benchmark Pt/C. Our work may shed new light on the rational design of advanced electrocatalysts with an assembled structure for energy-related applications.

Nitrogen doped carbon functionalized CoSe2 nanowires (CoSe2@N-C NWs), which act as potential oxygen evolution reaction (OER) catalysts with a large current density and high stability have been reported. Owing to the collaborative optimization of electrical conductivity, free adsorption energy and binding strength of OER intermediates, the prepared CoSe2@N-C NWs exhibit an enhanced 6.61-fold catalytic activity compared to the pristine CoSe2 NW electrode in 1.0 M KOH solution at the overpotential of 340 mV.

Developing new strategies for constructing highly efficient electrocatalyst is still of great significance for renewable energy conversion. In this work, a controlled in situ partial transformation strategy through a two-step hydrothermal reaction was developed for the successful synthesis of a novel Fe–Ni(OH)2@Ni–BDC/CFC (BDC stands for 1,4-benzenedicarboxylic acid and CFC represents carbon fiber cloth) composite nanosheets. The as-obtained Fe–Ni(OH)2@Ni–BDC/CFC demonstrated improved electrocatalytic activity for oxygen evolution reaction (OER) compared to pristine Fe–Ni(OH)2/CFC or Ni–BDC/CFC under alkaline condition. Owing to the coordination effect of the BDC ligand and strong electronic interaction in the distinct chemical composite, metal cations in the composite catalyst hold a higher oxidation state, which will significantly enhance the electrocatalytic performance. Thus, the strategy illustrated here is anticipated to provide a new opportunity for synthesizing composite electrocatalysts that are difficult to synthesize via conventional methods.

Oxygen vacancies are highly important for photocatalytic performance in bismuth oxychloride, but their preparation is limited to vacuum roasting and hydrogen annealing techniques at high temperatures (200–400 °C). Here we report a straightforward polyvinyl pyrrolidone (PVP)-mediated pathway for the synthesis of BiOCl nanoclusters (BiOCl-NCs) at room temperature, which can spontaneously and rapidly convert surface hydroxyl groups into oxygen vacancies during the photoactivation process. In situ FT-IR results present the formation process of oxygen vacancies and theoretical calculation results demonstrate that after the introduction of oxygen vacancies, a fresh electron donor level formed in the band gap of BiOCl, which is beneficial for visible-light photon energy absorption. As expected, the resulting BiOCl-NCs–OV exhibited remarkable photocatalytic capacity for degradation of organic dyes, reduction of toxic metal ions under all pH conditions and enhanced photocatalytic hydrogen evolution rate (1.21 mmol g−1 h−1) because of in situ generated oxygen vacancies, enhanced light absorption capability, and improved separation and transfer effectiveness of photoexcited charge carriers. Our protocol may open up new ways to design progressive photocatalysts for environment-related applications.

Some of the major difficulties hindering the synthesis of different types of colloidal nanocrystals are their complex synthetic methods and the lack of a universal growth mechanism in one system. Herein, we propose a general strategy of kinetically controlled seed-mediated growth to synthesize a family of penta-twinned gold nanocrystals. Specifically, different kinds of penta-twinned nanocrystals (truncated penta-twinned decahedra, truncated bipyramids, bipyramids, truncated bipyramids with tips, star-like penta-twinned nanocrystals, decahedra with concave edges, and decahedra) with tunable sizes and high purity were readily achieved in one system solely by tailoring the deposition kinetics of adatoms on different sites of decahedral seeds. The controllable deposition kinetics can be realized by changing the ratio of reductant/gold precursors (R), which dictates whether horizontal or vertical features along the 5-fold axis direction of Au decahedral seeds are produced. Additionally, the selective growth of a second metal (silver) on penta-twinned gold seeds can be reached through minor modification of R, which opens a new avenue for mechanistic investigation by visualizing the seed localization within the final particles. The present work demonstrates a general paradigm for the kinetic growth of penta-twinned crystals and would be extended to the synthesis of other families of nanocrystals., We report the synthesis of linear ADPr oligomers of defined length up to a pentamer using an improved solid phase method. Binding study with human oncogenic helicase ALC1 shows that ADPr oligomers bind to ALC1 in a length-dependent manner.

The employment of hybrid perovskite MAPbX3 (MA = CH3NH3+, X = Br or I) as photocatalysts in a photocatalytic hydrogen evolution reaction represents a promising approach to store solar energy. However, the toxicity of Pb makes these materials difficult to pass environmental evaluation while the intrinsic moisture sensitivity puts forward high anhydrous requirements in photocatalysts synthesis, storage, and application, which further reduces their service life. Herein, we demonstrate a hydrogen-bond-free strategy to synthesize moisture-stable hypotoxic hybrid perovskite for photocatalytic application by replacing traditional protonated countercations with alkylated countercations in a Pb-free hybrid system, which prevents water eroding hybrid perovskites via strong hydrogen bonds. A zero-dimensional Bi-based perovskite (3-ethylbenzo[d]thiazol-3-ium)4Bi2I10 (EtbtBi2I10) was synthesized, which contains dimeric (Bi2I10)4- formed by edge-sharing (BiI6) octahedra being different from the binuclear cluster in widely studied MA3Bi2I9. Theoretical calculations indicate that the electron communication between inorganic and organic moieties is responsible for its broadband absorption with a narrow band gap of 2.04 eV. EtbtBi2I10 exhibits excellent stability in distilled water, moisture air, acid solution, and UV-light irradiation. It shows effective photocatalytic performance in HI splitting to generate hydrogen with the performance comparable with MAPbI3. Introducing electron and hole-transporting channels drastically enhances the photocatalytic reaction.

Developing of high-performance and low-cost electrocatalysts is of great significance to reduce the overpotential and accelerated the reaction rate of oxygen evolution in water splitting and related energy conversion applications. Herein, Fe, O-dual doped Ni2P (Fe, O Ni2P) nanoarray is successfully synthesized on carbon cloth demonstrating enhanced electrocatalytic activity and stability for oxygen evolution reaction (OER) under alkaline media. The as-synthesized Fe, O Ni2P nanoarray exhibits obviously improved OER performance with a low overpotential of 210 mV at 10 mA cm−2 current density and a Tafel slope of 48 mV dec−1, as well as long-term durability. The strong coupling interaction induced changes in electronic structure lead to relatively higher oxidation state and stronger oxidation ability of the Fe, O Ni2P nanoarray, together with the high electrochemical surface area and good conductivity contribute to the superior OER performance. This work highlights the anion-cation dual doping strategy may be an effective method for fabrication of catalysts relating to energy conversion applications.

Introduction of defects in a controllable way is important to modulate the electronic structure of catalysts towards enhancement of electrocatalytic activity. Herein, we report that fluorine incorporation into cobalt phosphide alloy has a unique effect – it creates both F-anion doping and P vacancy, which results in nearly 15-fold enhancement in catalytic activity for hydrogen evolution reaction (HER) in neutral solution. The existence of dual defects in CoP is confirmed by extended X-ray absorption fine structure (EXAFS) curve fitting results and density functional theory calculation. We show that the dual-defect feature is beneficial to increasing the active site exposure, tuning the surface wettability and optimizing the electronic configuration of CoP for HER. Our fluorine based modulation protocol may be applicable to other metal alloy electrocatalysts towards more efficient energy conversion reactions. Agency for Science, Technology and Research (A*STAR) Ministry of Education (MOE) These authors contributed equally. We thank the financial support from Singapore Ministry of Education by AcRF Tier 2 grant (MOE2017-T2-1-073) and from Agency for Science, Technology, and Research (A*STAR), Singapore by AME Individual Research Grants (A1983c0026). This work is also supported by National Natural Science Foundation of China (Grant No. 21803031), Shandong Provincial Natural Science Foundation (ZR2019BEM007), Shandong postdoctoral innovative talents support plan.

Hierarchical composites represent a class of efficient electrocatalysts for renewable energy storage and conversion technologies owing to the porous structure and additional exposure of metal sites. Herein, a Ni-based metal organic frameworks (MOFs) (marked as Ni-BDC, BDC stands for 1,4-benzenedicarboxylic acid) nanosheet is successfully fabricated on hydroxyl iron oxide (FeOOH) array with carbon fiber cloth (CFC) as substrate. Benefit from the coordination tuning synergistic effect of the distinct chemical composition and the hierarchical structure for fast mass transportation, the as-obtained FeOOH@Ni-BDC illustrates excellent catalytic ability for electrochemical water oxidation with low overpotential of 270 mV to reach 10 mA/cm2 current and good durability in alkaline electrolyte. The novelty of this work lies in the modulation of electronic structure of the FeOOH with Ni-BDC through coordination effect to enhance the activity of the hierarchical composite electrocatalyst. This work is expected to guide the preparation of efficient electrocatalyst for new type alternative energy sources exploitation in near future.

We develop a method to prepare hollow FeP/Fe3O4 hybrid nanoparticles supported on carbon nanotubes (CNTs), which could be used as highly active and efficient electrocatalysts. The Fe@Fe3O4/CNT hybrids were first synthesized by annealing the CNTs adsorbed with Fe(NO3)3, followed by controlled phosphorization treatment. They exhibit an outstanding catalytic activity for oxygen evolution reaction (OER) with a low overpotential of 229 mV at a current density of 10 mA cm-2, a high turnover frequency value of 0.35 s-1 at an overpotential of 300 mV, and an ultralow Tafel slope of 27.6 mV dec-1, which is much better than that of FeP/Fe3O4, FeP/CNTs, Fe3O4/CNTs, and the commercial RuO2 electrocatalyst. More importantly, the Tafel slope is much lower than most non-noble metal-based OER electrocatalysts reported in the previous literature studies as far as we know. The excellent OER performance benefits from the electron transfer from Fe3O4 to FeP confirmed by X-ray photoelectron spectroscopy, together with good conductivity of CNTs. This hybrid structure supported on conductive CNTs may offer an efficient method to design earth-abundant and low-cost electrocatalysts for OER in practical applications.

The thinnest copper sulfur monolayer was stabilized by covalent and cuprophilic interaction in an organic copper chalcogenide, which shows oriented photoconductivity.

Noble metals have been extensively employed as high active catalysts for oxygen evolution reaction (OER), are usually subjected to serious surface transformation and poor structural stability, especially in acid media, which need imperatively remedied. Herein, the interfacial engineering of Ru via few-layer carbon (Ru@FLC) was carried out, in which FLC can significantly suppress the corrosion of Ru in acid media, ensuring the efficient interfacial charge transport between Ru and FLC. As a result, a low overpotentials@10 mA cm

Global environmental and energy crises have attracted wide attention and led to ongoing efforts to search for sustainable energy storage and conversion systems that can meet the energy needs of modern society. Electrocatalytic water splitting driven by renewable-energy-resource-derived electricity has been identified as a potential and practical strategy for future energy generation. Exploring nonprecious-metal-based electrocatalysts with high activity and tolerance is the prerequisite for the widespread application of this energy storage model. Heteroatom-regulated electrocatalysts with controllable components as well as electronic structure have unlimited potential toward the pursuit of high-efficiency electrocatalysts and they have been recognized as the perfect platform for establishing clear structure–property relationships. Therefore, in this review, the compositional engineering of recently reported transition-metal-compound-based water-splitting catalysts with multiple anion, cation, and zero-valent-element regulations were summarized. Particular emphasis is placed on the unique role of different doping configurations for each doping type in enhancing the electrocatalytic activities and stability of heteroatom-regulated electrocatalysts by exposing the active sites, regulating the electronic structure, and promoting the electrical conductivity. Finally, some personal perspectives on the design and development of heteroatom-doped electrocatalysts are shared to indicate the possible prospective development of transition-metal-compound-based electrocatalysts.

The challenge of sunlight-driven CO2 reduction is to achieve efficient photocatalysts with exceptional molecule adsorption ability and efficient charge-separation efficiency. Herein, 3D hierarchical Z-scheme Fe2O3@ZnIn2S4 core–shell nanorods are reasonably designed and synthesized and directly used as Z-scheme CO2 photoreduction catalysts. The Fe2O3@ZnIn2S4 core–shell nanorods exhibited a CO evolution rate of 37.13 μmol g−1 h−1, which is 2.15 times higher than that of the pristine ZnIn2S4 layers. The upgraded photocatalytic activity can be ascribed to the unique 3D hierarchical structure and efficient CO2 adsorption capacity, as well as the improved separation efficiency of charge carriers. This work may create new opportunities for developing other highly active complex hierarchical Z-scheme photocatalysts.

The environmental toxicity of Pb in inorganic–organic hybrid perovskite presents a major hurdle to commercialization, which has triggered intense research on exploring Pb-free alternatives. Soft in...

o-Nitrophenol (o-NP) and tetracycline hydrochloride (TCH) residues in various aquatic environments are two environmental contaminants, which are seriously dangerous to both social safety and the en...

Organic pollutions in wastewater are very harmful to environment and human health; their effective removal is important but still challenging. Copper iodine (CuI) is a promising semiconductor photocdatalyst, but still faces obvious drawbacks, e.g., only absorbing the UV light and serious electron-hole recombination. Herein, we report an effective hybrid copper(I) iodine-based photocatalyst [Cu4I4(EBT)5] (UJN Cu, EBT = 3-ethyl-1,3-benzothiazole-2-thione), which represents the first tetranuclear copper(I) iodine cluster been used for visible-light driven photocatalytic application. Importantly, the photocatalytic rate constant of UJN-Cu toward degrading organic dye pollution is three times larger than that for nitrogen-doped TiO2, and can retain similar activity after at least four runs. The holes are the dominated active species of photocatalyst UJN-Cu in such photocatalytic system. This work not only provides one promising copper(I) iodine-based semiconductor photocatalyst, but also unveils the feasibilities of tetranuclear copper(I) iodine cluster for wastewater purification.

Bismuth oxychloride ultrathin nanoplates (BiOCl-UTNs) are highly active, but their preparation are limited to closed-vessel hydrothermal and solvothermal techniques at high temperatures (110-180 °C). Here we report a straightforward poly(sodium 4-styrenesulfonate) (PSS)-mediated route for the large-scale synthesis of BiOCl-UTNs at room-temperature. In an open vessel, 6.15 g of BiOCl-UTNs with 3-5 nm thickness, and planar dimensions of 30-50 nm were produced. The strong electrostatic interaction between PSS and [Bi2 O2 ]2+ layers inhibited the growth rate of BiOCl nanoplates along direction, and Na+ ions governed the electrolyte sedimentation to produce BiOCl-UTNs. The resulting BiOCl-UTNs exhibited high photocatalytic activity for the degradation of antibiotics and organic dyes because of their large specific surface area, increased light absorption ability, and fast separation and transfer efficiency of the photoexcited charge carriers.

Au@Ag@Ag2S heterogeneous nanorods (NRs) with two strong plasmonic absorptive bands were developed for boosting the performance of dye-sensitized solar cells, and the remarkably enhanced plasmonic devices were achieved. By doping different concentrations of the Au@Ag@Ag2S NRs within the TiO2 photoanode layers, various enhanced effects of the plasmonic devices were obtained. With the incorporation of the typical Au@Ag@Ag2S NRs (their aspect ratios: 2.7) into the TiO2 photoanodes, the top efficiency of 6.51% of the fabricated plasmonic photovoltaic devices at their doped concentrations of the 2.31% was observed, exhibiting dramatic 40% enhancement than that of the conventional dye-sensitized solar cells (bare device: 4.65%). Benefiting from effective surface plasmon effects of the Au@Ag@Ag2S NRs, the light-harvesting abilities of photoanodes and dyes in devices are dramatically enhanced, which in return boost the whole performance of photovoltaic devices significantly.

Exploring of efficient electrocatalysts based on nonprecious metals is of great importance for the development of hydrogen energy and related energy conversion technologies. Metallic Ni3Fe nanoarray is firstly fabricated on carbon cloth as efficient oxygen evolution electrocatalyst. Co, N-dual doped carbon shell derived from metal organic framework is coated on the Ni3Fe nanoarray to enhance electrocatalytic activity and stability. The as-prepared composite catalyst only needs a low overpotential of 170 mV to drive 10 mA cm−2 current density in alkaline solution, and an overpotential of 370 mV in carbonate buffer solution. Moreover, the catalyst exhibit excellent durability in both alkaline and carbonate electrolyte. Good conductivity, rich active sites, fast electron transport process and synergistic effect between Ni3Fe and the doped carbon together contributes to the efficient catalytic performance. This synthesis approach provides a new way to develop efficient nonprecious metal based electrocatalysts for water oxidation and other energy-related applications.

The introduction of heteroatoms is one of the most important ways to modulate the intrinsic electronic structure of electrocatalysts to improve their catalytic activity. However, for transition metal chalcogenides with highly symmetric crystal structure (HS-TMC), the introduction of heteroatoms, especially those with large atomic radius, often induces large lattice distortion and vacancy defects, which may lead to structural phase transition of doped materials or structural phase reconstruction during the catalytic reaction. Such unpredictable situations will make it difficult to explore the connection between the intrinsic electronic structure of doped catalysts and catalytic activity. Herein, taking thermodynamically stable cubic CoSe2 phase as an example, we demonstrate that nitrogen incorporation can effectively regulate the intrinsic electronic structure of HS-TMC with structural phase stability and thus promote its electrocatalytic activity for the hydrogen evolution activity (HER). In contrast, the introduction of phosphorus can lead to structural phase transition from cubic CoSe2 to orthorhombic phase, and the structural phase of phosphorus-doped CoSe2 is unstable for HER.

Nitrogen doped carbon functionalized CoSe

Intervertebral disc degeneration (IVDD) is a multifactorial pathological process associated with low back pain in which nucleus pulposus cell senescence is disrupted. Increasing evidence reveals that IVDD can be modulated by microRNAs (miRNAs or miRs). In the current study, we set out to elucidate the role of miR-199a-5p in nucleus pulposus cell apoptosis and IVDD progression. After sample collection, we found highly expressed miR-199a-5p in nucleus pulposus tissues of both patients diagnosed with IVDD and in IVDD rat models. Next, normal and degenerated nucleus pulposus cells were isolated and transfected with miR-199a-5p mimic, miR-199a-5p inhibitor, overexpressed sirtuin 1 (oe-SIRT1), and oe-p21, followed by detection of nucleus pulposus cell apoptosis and proliferation. In addition, the binding of miR-199a-5p and SIRT1, the interaction between p21 and SIRT1, and the regulation of p21 acetylation by SIRT1 were analyzed. We found that miR-199a-5p overexpression promoted nucleus pulposus cell apoptosis and IVDD. Overexpression of SIRT1 countered the effect of miR-199a-5p overexpression, while overexpression of p21 reversed the effect of miR-199a-5p silencing. Also, miR-199a-5p inhibited SIRT1, promoted p21 acetylation, and upregulated p21 expression, thus accelerating nucleus pulposus cell apoptosis and IVDD. Overall, miR-199a-5p promotes nucleus pulposus cell apoptosis and IVDD by suppressing SIRT1-dependent deacetylation of p21., Graphical Abstract, miR-199a-5p, found to be highly expressed in nucleus pulposus tissues, promoted nucleus pulposus cell apoptosis and aggravated the progression of IVDD by disrupting SIRT1-dependent deacetylation of targeted p21. Thus, targeting the miR-199a-5p/SIRT1/p21 axis would shed light on the development of new therapeutic strategies for IVDD.

Hierarchical hetero-Ni3Se4@NiFe LDH (layered double hydroxide) micro/nanosheets were prepared by coupling NiFe LDH nanosheets with Ni3Se4 micro-sized sheets, and could be used as effective bifunctional electrocatalysts for water splitting. Benefiting from the strong electronic interaction between the NiFe LDH nanosheets and Ni3Se4 micro-sized sheets, the hierarchical hetero-Ni3Se4@NiFe LDH micro/nanosheets are endowed with enhanced charge transfer and reaction kinetics. As a result, the obtained hierarchical hetero-Ni3Se4@NiFe LDH/CFC (carbon fiber cloth) electrode shows optimized hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) properties in alkaline medium with a small overpotential of 85 mV and 223 mV at the current density of 10 mA cm−2, respectively. When the hierarchical hetero-Ni3Se4@NiFe LDH/CFCs are used as bifunctional electrodes for overall water splitting in a two-electrode electrolyzer, the current density of 10 mA cm−2 is derived at a cell voltage of 1.54 V. Moreover, due to the stability of the novel hierarchical hetero-micro/nanostructure, the as-prepared Ni3Se4@NiFe LDH/CFC exhibited high stability in the electrochemical processes over 100 h. This work highlights the importance of constructing efficient bifunctional electrocatalysts for overall water splitting by rational design of heterostructures.

We develop a method to prepare hollow FeP/Fe

Facile fabrication of high-performance catalyst based on low-cost metals for sustainable hydrogen evolution is still a matter of cardinal significance. However, synthetic approaches for electrocatalyst are usually complicated and the yields are often low. Herein, we report a one-step simple method for the large-scale synthesis of Co/Ni-MoO2 composite as efficient and stable hydrogen evolution reaction (HER) electrocatalyst to drive 10 mA cm−2 current density with a low overpotential of 103 mV in basic media. Co-MoO2 and Ni-MoO2 were also prepared using this method with overpotential of 137 and 130 mV, respectively, to gain the same current density. These results indicate that this facile synthesis approach is of great practical importance as it can be easily used for large-scale preparation of electrocatalysts in industry.

A facile and scalable one-step thermal treatment method is developed to produce Co/CoOx encapsulated in N-, O-, and S-tridoped three-dimensional porous carbon material to catalytic hydrogen evoluti...

Active site number, water dissociation, and hydrogen adsorption free energy are the three main parameters for regulating the activity of electrocatalysts for hydrogen evolution reaction (HER) in alkaline media. However, at present, simultaneous modulations of these three parameters for alkaline HER still remain challenging. In this work, we take CoP as the model material and demonstrate that a metal and nonmetal dual-doping strategy can achieve simultaneous modulation of these three parameters by inducing lattice irregularity and optimizing the electronic configuration in CoP nanomaterials. Benefiting from the oxygen and copper dual-doping collective effect, the optimized O,Cu–CoP nanowire array electrode shows nearly 10-fold enhancement in catalytic activity for alkaline HER compared to a pure CoP nanowire electrode. Our work may provide a new concept to boost performance of nonprecious metal electrocatalysts for alkaline HER.

Using a new low-temperature dynamic triaxial apparatus, the influence law of freezing-thawing cycles on clay shear strength is studied. In this research, the concept of correction coefficients of freezing-thawing cycles on clay static strength, cohesion and internal friction angles is proposed, and the change patterns, correction curves and regressive formulae of clay static strength, cohesion and internal friction angles under freezing-thawing cycles are given. The test results indicate that with increasing numbers of freezing-thawing cycles, the clay static strength and cohesion decrease exponentially but the internal friction angle increases exponentially. The performance of static strength, cohesion and internal friction angles are different with increasing numbers of freezing-thawing cycles, i.e., the static strength decreases constantly until about 30% of the initial static strength prior to the freezing-thawing cycling and then stays basically stable. After 5–7 freezing-thawing cycles, the cohesion decreases gradually to about 70% of the initial cohesion. The internal friction angle increases about 20% after the first freezing-thawing cycle, then increases gradually close to a stable value which is an increase of about 40% of the internal friction angle. The freezing-thawing process can increase the variation of the density of the soil samples; therefore, strict density discreteness standards of frozen soil sample preparation should be established to ensure the reliability of the test results.

We report a simple method for preparation of self-supported nanoporous Cu-doped CoP nanorod arrays on carbon cloth (Cu-CoP NRAs/CC) by a hydrothermal and low-temperature phosphidation process, whic...

Validation of the vibration-excited subsidence model is limited for seasonally frozen soil. Based on constant-amplitude load tests by a new low-temperature triaxial device under realistic confining pressure, amplitudes of dynamic stress, consolidation and freezing methods, we determined the residual strain behavior and validated the vibration-excited subsidence model of frozen soil during frozen period considering the influence caused by temperatures, loading amplitudes and loading cycles. Results show that the residual strain during the frozen period increased with increasing cycles of loading, but decreased with decreasing temperatures. The residual strain development model indicates that residual strain increased dramatically in the initial loading cycles followed by a gradual increase over time. In most cases, the frozen soils tested are not failing that the developing curves of residual strains under different temperatures develop nearly parallel after certain cycles of loading. Residual strain was fairly sensitive to the negative temperatures at large amplitudes of dynamic stress, and the influence of low temperature was limited after a critical temperature in − 5 °C to − 10 °C. The two-parameter exponential model is able to express exactly the change rule of vibration-excited subsidence under different temperature. With the increase of dynamic stress amplitude, parameters A and B increase rapidly, especially when the soil approaches the failure state. In contrast, parameters A and B decrease as temperature decreases, but decrease little as the temperature decreases below the critical temperature. Our test layout overcomes previous testing limitations such as excessively large consolidating pressure and dynamic loading so that the test results are more consistent with the real conditions of seasonally frozen soil. The vibration-excited subsidence of subgrade in seasonally frozen soil regions could be predicted through this model.

We develop a facile laser-irradiation induced alloying and subsequent chemical etching method to prepare spongy AuAgPt alloy nanospheres (spongy AuAgPt NSs) with high-index facets, rich grain boundaries and subtle lattice distortion as highly active electrooxidation catalysts. The key to preparing such spongy AuAgPt NSs for their excellent electrocatalytic activity is the alloying process induced by laser irradiation, forming rich grain boundaries and subtle lattice distortion due to the quick fusion and quenching process, which is completely different from traditional thermal annealing alloying. After chemical dealloying, the nanopores were formed and a large amount of high-index facets were successfully introduced into the spongy AuAgPt NSs. The spongy AuAgPt NSs exhibited superior methanol oxidation reaction (MOR) activity (1.62 A mgPt−1), which was 5.1 times higher than that of Pt black (0.32 A mgPt−1), and they also showed outstanding stability for the MOR after long-term cycles. The enhanced catalytic activity could be attributed to the abundant high-index facets, grain boundaries and subtle lattice distortion of spongy AuAgPt NSs formed in this laser-irradiation induced alloying and subsequent chemical etching process. The present work provides a new efficient strategy for the rational design of 3D spongy electrocatalysts with both high activity and improved durability for promising applications in electrocatalysis, biosensing, energy conversion, etc.