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To study the residual performance of the welded hollow spherical joint after exposure to high temperatures. A total of 12 welded hollow spherical joint specimens are heated to six different preselected temperatures and subsequently air-cooled and water-cooled to the ambient temperature. Axial compressive tests are thereafter performed until the joints are damaged. The displacement characteristics, strain development, failure modes, stiffness, ductility, and load bearing capacity of specimens are investigated. The results show that the mechanical properties of spherical joints are considerably affected by the temperatures and cooling methods. Under the air-cooling condition, both the stiffness and compressive load of spherical joints decrease with an increase in the exposed temperature, and the ductility increases considerably. Under the water-cooling condition, the stiffness and ductility of spherical joints decrease with the increase in exposed temperature. The yield and ultimate loads decrease when the temperature is up to 500 °C and then gradually increase when the temperature exceeds 500 °C.

In this work, we rationally designed a series of crystalline and stable dioxin-linked metallophthalocyanine covalent organic frameworks (COFs; MPc-TFPN COF, M=Ni, Co, Zn) under the guidance of reticular chemistry. As a novel single-site catalysts (SSCs), NiPc/CoPc-TFPN COF exhibited outstanding activity and selectivity for electrocatalytic CO2 reduction (ECR; Faradaic efficiency of CO (FECO )=99.8(±1.24) %/ 96.1(±1.25) % for NiPc/CoPc-TFPN COF). More importantly, when coupled with light, the FECO and current density (jCO ) were further improved across the applied potential range (-0.6 to -1.2 V vs. RHE) compared to the dark environment for NiPc-TFPN COF (jCO increased from 14.1 to 17.5 A g-1 at -0.9 V; FECO reached up to ca. 100 % at -0.8 to -0.9 V). Furthermore, an in-depth mechanism study was established by density functional theory (DFT) simulation and experimental characterization. For the first time, this work explored the application of COFs as photo-coupled electrocatalysts to improve ECR efficiency, which showed the potential of using light-sensitive COFs in the field of electrocatalysis.

The design of a powerful heterojunction structure and the study of the interfacial charge migration pathway at the atomic level are essential to mitigate the photocorrosion and recombination of electron-hole pairs of CdS in photocatalytic hydrogen evolution (PHE). A temperature-induced self-assembly strategy has been proposed for the syntheses of Prussian blue analogue (PBA)/CdS nanocomposites with beaded structure. The specially designed structure had evenly exposed CdS which can efficiently harvest visible light and inhibit photocorrosion; meanwhile, PBA with a large cavity provided channels for mass transfer and photocatalytic reaction centers. Remarkably, PB-Co/CdS-LT-3 exhibits a PHE rate of 57 228 μmol h-1 g-1, far exceeding that of CdS or PB-Co and comparable to those of most reported crystalline porous material-based photocatalysts. The high performances are associated with efficient charge migration from CdS to PB-Co through CN-Cd electron bridges, as revealed by the DFT calculations. This work sheds light on the exploration of heterostructure materials in efficient PHE.

The sluggish kinetics and unclear mechanism have significantly hindered the development of Li-CO2 batteries. Here, a Li-CO2 battery cathode catalyst based on a porphyrin-based covalent organic framework (TTCOF-Mn) with single metal sites is reported to reveal intrinsic catalytic sites of aprotic CO2 conversion from the molecular level. The battery with TTCOF-Mn exhibits a low overpotential of 1.07 V at 100 mA/g as well as excellent stability at 300 mA/g, which is one of the best Li-CO2 battery cathode catalysts to date. The unique features of TTCOF-Mn including uniform single-Mn(II)-sites, fast Li+ transfer pathways, and high electron transfer efficiency contribute to effective CO2 reduction and Li2CO3 decomposition in the Li-CO2 system. Density functional theory calculations reveal that different metalloporphyrin sites lead to different reaction pathways. The single-Mn(II) sites in TTCOF-Mn can activate CO2 and achieve an efficient four-electron CO2 conversion pathway. It is the first example to reveal the catalytic active sites and clear reaction pathways in aprotic Li-CO2 batteries.

Polyoxometalates (POMs), possessing multiple-electron redox ability, controllable size, and precise structure, hold much promise to be applied as anode materials in lithium-ion batteries (LIBs). Ho...

As a common type of joint used in spatial grid structures, the tensile performance of bolt-sphere joints directly affects the safety of the spatial grid structure under fire. To study the tensile properties of the bolts in sphere joints under fire, the four sets of 36 bolt-sphere joints consist of M20, M24, M30, and M36 high-strength bolts were conducted in elevated temperature by steady-state test. Therefore, the tensile bearing capacity of the bolt-sphere joint was obtained under different elevated temperatures. Experimental results show the destroyed section of the bolt-sphere joint that occurs in the thread of the high-strength bolt at the intersection of the sphere because of the maximum concentration of stresses that occurred in areas of destruction. The brittle fracture of bolt-sphere joints happened when the temperature is below 400 ℃. As the temperature increased, the neck shrinkage of the damaged section of the bolt becomes more apparent, and the ductile failure of the bolt-sphere joint occurred. The stiffness and the bearing capacity of bolt-sphere joints decreased gradually as the temperature rose. Conversely, the ductility was gradually increasing. When the temperature was greater than 300 ℃, the stiffness and the bearing capacity of the bolts in sphere joint decreased rapidly. The bearing capacity reduction coefficient of the high-strength bolts with different diameters were next to the same at elevated temperatures. According to the experimental data, the formulas of the tensile bearing capacity reduction coefficient of bolt-sphere joints were obtained.

A series of stable heterometallic Fe2 M cluster-based MOFs (NNU-31-M, M=Co, Ni, Zn) photocatalysts are presented. They can achieve the overall conversion of CO2 and H2 O into HCOOH and O2 without the assistance of additional sacrificial agent and photosensitizer. The heterometallic cluster units and photosensitive ligands excited by visible light generate separated electrons and holes. Then, low-valent metal M accepts electrons to reduce CO2 , and high-valent Fe uses holes to oxidize H2 O. This is the first MOF photocatalyst system to finish artificial photosynthetic full reaction. It is noted that NNU-31-Zn exhibits the highest HCOOH yield of 26.3 μmol g-1 h-1 (selectivity of ca. 100 %). Furthermore, the DFT calculations based on crystal structures demonstrate the photocatalytic reaction mechanism. This work proposes a new strategy for how to design crystalline photocatalyst to realize artificial photosynthetic overall reaction.

BackgroundThe aim of this study was to assess the clinical performance of lithium disilicate glass-ceramic onlays for the treatment of tooth defects and to evaluate the clinical performance and whether they are worth more extensive use as that of the full crown. MethodsPatients who received treatment by lithium disilicate glass-ceramic onlays at the Western China Hospital of Stomatology were recalled after 1~4 years. The clinical performance and patients’ satisfaction of onlays for various tooth defects, cracked or uncracked teeth and endodontically treated or vital teeth were retrospectively evaluated with a combination of modified United States Public Health Service Criteria and questionnaire survey. Statistical analysis was performed by using the chi-squared test, Kaplan–Meier analysis and Log-rank test (a = 0.05) where appropriate. ResultsA total of 154 patients with 166 onlays were recalled for clinical examination. Of the 166 onlays examined, 65 (39.19%) were occlusal onlays, 92 (55.42%) were proximal-occlusive onlays and 9 (5.42%) were buccal-or lingual-occlusal onlays. The clinical performance of O and PO onlays was not significantly different (P > 0.05), according to USPHS Criteria. Kaplan-Meier analysis showed that the 4-year survival rate of O and PO onlays was 95.4% and 97.8%, respectively while there was no failure happened in buccal-or lingual-occlusal onlays. Log- rank test showed that the kinds of defects/onlays, tooth vitality and tooth crack had no influence on the survival rate (P > 0.05). The overall satisfaction rate was more than 98%.ConclusionsThis medium-term analysis indicated that lithium disilicate glass-ceramic onlays achieved satisfactory clinical performance for the restoration of different tooth defects. The survival rate of onlays was comparable to that of full crown. Different kinds of tooth defects, tooth vitality and tooth crack did not influence performance.Trial registrationThe study was approved by the Medical Ethics Committee of West China Hospital of Stomatology of Sichuan University with the approval number: WCHSIRB-D-2021-300. Consent to participate was not applicable.

High-field magnetic resonance imaging (MRI, 3.0T and above) offers numerous advantages for imaging the human body over lower-field strengths. However, it suffers from unwanted fast spatially-varying main (B0 ) fields caused by the susceptibility mismatch at the tissue interfaces. When this is combined with the anatomical complexity of the human body, undesirable image artifacts can become damaging as they can compromise potential image contrasts, limit the use of accelerated imaging, and interfere with clinical interpretation. Consequently, these limitations restrict the effective utilization of high-field body MRI and emphasize the need for a major improvement in B0 field homogeneity to take full advantage of the ever increased B0 field. Here we introduce a Unified shim-RF Coil (UNIC) to overcome this existing bottleneck by transcending the conventional low-efficiency, distantly located B0 shim coils. UNIC allows a shim array to be freely allotted and seamlessly integrated into a standard surface RF coil, thus maximizing both the performance of RF receive sensitivity and effective B0 shimming. We demonstrate the capacity of the UNIC approach through detailed characterization of the coil design, prototyping a body coil integrating the UNIC features, and conducting in-vivo imaging of deep organs adjacent to the lung. Our studies provide evidence that UNIC enables homogeneous B0 fields in the liver and the heart, where strong image artifacts are known to occur, and hence facilitate the acquisition of unprecedented image quality in a clinical 3.0T scanner. Further, UNIC’s design is practical as it overcomes one of the most, if not the most, critical limitations of the state-of-the-art high-field MRI with minimal changes to the current MRI hardware architecture. Accordingly, the proposed technique offers opportunities for major advancements in noninvasive imaging of deep organs with high-field imaging in a way it has not been possible thus far.

Efficient conversion of carbon dioxide (CO2) into value-added products is essential for clean energy research. Design of stable, selective, and powerful electrocatalysts for CO2 reduction reaction (CO2RR) is highly desirable yet largely unmet. In this work, a series of metalloporphyrin-tetrathiafulvalene based covalent organic frameworks (M-TTCOFs) are designed. Tetrathiafulvalene, serving as electron donator or carrier, can construct an oriented electron transmission pathway with metalloporphyrin. Thus-obtained M-TTCOFs can serve as electrocatalysts with high FECO (91.3%, −0.7 V) and possess high cycling stability (>40 h). In addition, after exfoliation, the FECO value of Co-TTCOF nanosheets (~5 nm) is higher than 90% in a wide potential range from −0.6 to −0.9 V and the maximum FECO can reach up to almost 100% (99.7%, −0.8 V). The electrocatalytic CO2RR mechanisms are discussed and revealed by density functional theory calculations. This work paves a new way in exploring porous crystalline materials in electrocatalytic CO2RR., The study of covalent organic frameworks (COFs) in electrocatalytic CO2 reduction reaction (CO2RR) has drawn much attention. Here the authors show a series of tetrathiafulvalene based COFs designed and exfoliated into nanosheets which exhibit high electrocatalytic CO2RR performance.

Recently, a new class of lithium chlorides and bromides (e.g., Li3YCl6 and Li3YBr6) were reported to be promising solid-state electrolytes with high ionic conductivity in all-solid-state battery cells. However, their response under mechanical loading is not known which is critical as mechanical properties can play a pivotal role in reducing interfacing resistance between electrolytes and electrodes. To address this issue, herein, we report the thermo-physical properties of these lithium chlorides and bromides using density functional theory calculations. It was found that the new structures possess relatively larger shear moduli than those of thio-phosphate-type solid-state electrolytes and smaller Young's moduli than those of Garnet-type solid-state electrolytes. This suggests that the new halide materials can be more effective in suppressing the formation of lithium dendrites, accommodating volumetric changes of electrode materials and preventing their own degradation. Meanwhile, Poisson's ratio and Pugh's indicator calculations showed that Li3YCl6 and Li3ScCl6 possess improved ductility than other halide candidates, and thus hold promise as solid-state electrolytes. On the other hand, owing to their relatively high thermal conductivities, lithium bromides were found to be more advantageous in conducting heat which is important to ensure safety. These results provide fundamental insights into the mechanical properties of lithium chlorides and bromides and contribute to the rational mechanical design of solid-state electrolytes and the development advanced all-solid-state batteries.

Temperature is a major factor affecting physical and mechanical rock properties. With increasing temperature, a series of variations enlarge the internal defects within rocks, resulting in physical and mechanical rock property variations. To explore the influence of temperature on the physical and micro-structure of limestone, the weighing test and P-wave velocity test were conducted on limestone after exposure to high temperature to reveal the evolution of the limestone mass and P -wave velocity. XRD, XRF, SEM, and mercury intrusion tests were also carried out to examine the mineral composition and content, micro-fracture morphology, porosity, and fractal dimension. The limestone mass and P-wave velocity decrease with increasing temperature. When T ≤ 400 °C, there is no obvious change in chemical composition and crystal structure; when T = 400–500 °C, the diffraction intensity of partial calcite decreases, and dolomite decomposes gradually; when T > 500 °C, illite decomposes gradually, while dolomite decomposes completely; and the diffraction intensity of calcite is significantly reduced. When T ≤ 200 °C, changes in trace minerals or impurities containing K2O and Na2O and the decomposition of illite oxide are dominant; when T = 400–600 °C, illite oxide, trace minerals, or impurities containing K2O and calcium hydroxide begin to decompose. When T = 600–800 °C, magnesite and dolomite begin to decompose. When T ≤ 200 °C, micro-fracture surfaces change slightly. When T = 200–500 °C, micro-fractures begin to develop and propagate gradually, most of which are intergranular cracks with a small number of transgranular cracks. When T > 500 °C, transgranular cracks occur in samples with locally broken crystals, and the cracking of the crystal structure occurs with increasing pore size. With increasing temperature, the limestone pore fractal dimension decreases gradually, and the higher the temperature, the greater the decrease. 400 °C to 500 °C is the temperature threshold interval that causes the pore structure change. These new pores, resulting from the increasing temperature, are primarily mesopores with a pore diameter of 1.0–10.0 μm. This research provides a scientific basis for the design and construction of rock engineering projects to be subjected to high temperatures, deep geological radioactive nuclear waste disposal sites, deep mines, and the exploitation of geothermal resources.

Here, we report our trials to regulate the luminescence performance of the macrocyclic samarium(III) complex and prepare four excellent luminescent Sm(III) complex-doped poly(methylmethacrylate) (PMMA) composites. Four 23-membered [1 + 1] Schiff-base macrocyclic mononuclear Sm(III) complexes, Sm-2a–Sm-2d, originating from dialdehydes with different pendant arms and 1,2-bis(2-aminoethoxy)ethane, have been constructed by the template method. Crystal structures reveal that every Sm(III) ion with the coordination geometry of a distorted bicapped square antiprism is capsulated by the macrocyclic cavity environment forming the “lasso-type” protection. Relative photophysical properties of macrocyclic Sm(III) complexes are carefully investigated in solid-state, methanol solution, and doped PMMA film, and all these show characteristic emissions of the Sm(III) ion associated with satisfactory lifetimes and quantum yields in all media, which could be comparable to reported outstanding examples. Especially, the luminescence performance for this type of Sm(III) complex could be regulated in the solid state by the use of different functional groups in the pendant arm while it is not achieved in solution and the doped PMMA composite. High emitting and air-stable plastic materials could be obtained when these Sm(III) complexes are doped in PMMA with 0.1 wt % mixing ratio, and the corresponding maximum lifetime and quantum yield are 61.2 μs and 0.63% in the case of complex Sm-2a, respectively. We believe that these highly luminescent “lasso-type” Sm(III) complexes and doped PMMA composites are valuable references in the design of luminescent lanthanide(III) hybrid materials.

Solar energy-driven conversion of CO2 into fuels with H2 O as a sacrificial agent is a challenging research field in photosynthesis. Herein, a series of crystalline porphyrin-tetrathiafulvalene covalent organic frameworks (COFs) are synthesized and used as photocatalysts for reducing CO2 with H2 O, in the absence of additional photosensitizer, sacrificial agents, and noble metal co-catalysts. The effective photogenerated electrons transfer from tetrathiafulvalene to porphyrin by covalent bonding, resulting in the separated electrons and holes, respectively, for CO2 reduction and H2 O oxidation. By adjusting the band structures of TTCOFs, TTCOF-Zn achieved the highest photocatalytic CO production of 12.33 μmol with circa 100 % selectivity, along with H2 O oxidation to O2 . Furthermore, DFT calculations combined with a crystal structure model confirmed the structure-function relationship. Our work provides a new sight for designing more efficient artificial crystalline photocatalysts.

Hydrogen (H2) plays a vital role both as a reactant in petrochemical processes and as an energy carrier and storage medium. When produced from carbon-containing feed stocks, such as fossil fuels and biomass, hydrogen is typically produced as a mixture with carbon dioxide (CO2), and must be subsequently separated by the associated energy, with an invertible energy penalty. In this study, the process for the removal of carbon dioxide from CO2 - H2 mixtures by de-sublimation was analysed. This process is particularly relevant to the production of liquid hydrogen (LH2) at cryogenic temperatures, for which cooling of the H2 stream is already necessary. The solid – gas equilibrium of CO2 - H2 was studied using the Peng-Robinson equation of state which provided a wide range of operating conditions for process simulation. The de-sublimation process was compared with selected conventional separation processes, including amine-based absorption, pressure swing adsorption and membrane separation. In the scenario in which the resulting products, carbon dioxide and hydrogen, were subsequently liquefied for transportation and storage at 10 bar and −46 °C, and 1 bar and −251.8 °C, respectively. The overall energy consumption per kg of CO2 separated (MJ/kgCO2), was found to follow the order: 8.19–11.21 for monoethanolamine (MEA) absorption; 1.81–8.93 for membrane separation; 1.53–5.69 for pressure swing adsorption; and 0.81–3.35 de-sublimation process. Each process was evaluated and compared on the bases of electricity demand, cooling water usage, high-pressure steam usage, and refrigeration energy requirements. Finally, the advantages and disadvantages were discussed and the feasibility and sustainability of the processes for application in the production of liquid hydrogen were assessed.

Small break loss of coolant accident (SBLOCA) is one of the most important severe accidents in nuclear heating reactor. Nuclear heating reactor designed by Tsinghua University, whose primary loop i...

This study derived the analytical solutions for the deflection, bending moment and shear force of a hard roof under an arbitrary front abutment pressure for both the initial and periodic fracture problems using the elastic foundation beam model. With the assumption that the overburden pressure is constant in a small section, the roof subjected to arbitrarily distributed pressures is divided into a number of sufficiently small sections, whose closed-form solutions can be obtained easily. The proposed analytical solutions are validated by comparisons with those calculated using a model reported in the literature, in which the overburden pressure is assumed to follow a normal distribution. The parametric studies on the foundation stiffness, front abutment pressure and support resistance show that: (1) with the decrease of elastic foundation stiffness, the deflection and the maximum bending moment significantly increase, and the shear force significantly changes in the unmined region; (2) as the peak point position moves inside the coal wall, the deflection of the goaf roof, as well as the maximum bending moment and shear force, obviously decrease; (3) with the increase of support resistance, the maximum bending moment and deflection significantly decrease, and the shear force significant decreases in the hydraulic support region; (4) when the coal seam is soft and peak position of the front abutment pressure is near the coal wall, initial fracture occurs at the midspan; otherwise, it occurs inside the coal wall. For the periodic fracture condition, the fracture position is closer to the coal wall when the coal seam is harder, and the fracture length increases when the peak position of front abutment pressure moves inside the coal wall.

A series of Ce3+, Dy3+ doped Ca3(P1-xBxO4)2 phosphors were synthesized by a high temperature solid-state reaction method, and their corresponding structure, morphology, and luminescence properties were investigated. It is found that the crystal phase transition from β-Ca3(PO4)2 to Ca5(PO4)3(OH) gradually occurs with increasing the boron content in the phosphors, which can provide various local environments for the doping ions and consequently affect the luminescence properties of the phosphors. A red shift of the emission peak of Ce3+ was revealed upon incorporation of boron into Ce/Dy co-doped phosphors. In addition, the luminescence properties could be well modulated by varying the excitation wavelength. The developed phosphors have great potential as a kind of single component white light-emitting phosphors for white light-emitting diodes.

The design of selective and efficient covalent organic frameworks (COFs) based electrocatalysts with tunable morphology for efficient CO2 reduction reaction (CO2RR) to CH4 is highly desirable. Here, two kinds of anthraquinone-based COFs (i.e., AAn-COF and OH-AAn-COF) with tunable 1D superstructures (e.g., nanofibers (NF) and hollow tubes (HT)) have been produced via Schiff-base condensation reaction. Interestingly, a rarely reported nanosheet-based self-template mechanism and a nanosheet-crimping mechanism have been demonstrated for the production of COF-based nanofibers and hollow tubes, respectively. Besides, the obtained COF-based superstructures can be post-modified with transition metals for efficient CO2RR. Specifically, AAn-COF-Cu (NF) and OH-AAn-COF-Cu (HT) exhibit superior faradaic-efficiency with CH4 (FECH4) of 77% (−128.1 mA cm−2, −0.9 V) and 61% (−99.5 mA cm−2, −1.0 V) in a flow-cell, respectively. Noteworthy, the achieved FECH4 of AAn-COF-Cu (NF) (77%) the is highest one among reported crystalline COFs. This work provides a general methodology in exploring morphology-controlled COFs for electrocatalytic CO2RR.

This paper reports a new optical fiber thermometer (OFT) for ultra-high temperature measurement under extreme environments, such as in molten steels. This sapphire fiber-based OFT was designed by coating the sapphire fiber core with a nanorod cladding material, which is then housed inside the ceramic tube, the cladded sapphire fiber can collect thermal emissions from ceramic tube and couple the emission to a near-infrared spectrometer with minimal loss. After dipping OFT into molten steel, real-time temperature can be determined by analyzing the emission spectra using a polynomial curve fitting or a machine learning-based classification algorithm.

Grouting is a common and important technique for water bursting prevention in coal mines; the success of grouting in coal mines depends highly on the flowability of grouting materials and the strength of the hardened body as well. In this paper, a series of performance tests, in terms of the water-cement ratio, viscosity, drainage rate, presetting time, final setting time, compressive strength, and permeability were conducted on the cement-fly ash-based grout at various mixture ratios. The evolution of these performances versus different mixture ratios was analyzed; targeting at the reasonable flowability and hardened strength of grouting materials, an optimized mixture ratio was recognized for water bursting prevention in coal mines. Furthermore, the diffusion experiments of optimized grout material were designed taking into account the influence of confining and hydraulic pressure in the porous medium. As a result, the confining and hydraulic pressures have a linear negative correlation with the diffusion distance of grout materials. These results have guiding significance to water bursting prevention in coal mines.

A resonant pyroelectric detector was demonstrated to support narrowband and tunable photopyroelectric effect in the near-infrared region. The narrowband pyroelectric device was built on a chalcogenide-metal-fluoropolymer (As2S3-Ag-PVDF) nanograting membrane, which was fabricated inexpensively using a solvent-assisted imprint lithography process. Under the resonant condition, the device exhibited a responsivity of 1.36 V/W. The device’s absorption and pyroelectric characteristics can be tuned using a bias voltage applied to the membrane.

The fabrication of scaffolds with suitable chemical, physical, and electrical properties is critical for nerve cell adhesion and proliferation. Recently, electrical stimulation on conductive polymers has been applied to construct functional nerve cell scaffolds. Herein, we prepared natural polymer (cellulose)/conductive polymer nanofibrous mats, i.e., electrospun cellulose (EC)/poly N-vinylpyrrole (PNVPY) and EC/poly(3-hexylthiophene) (P3HT) through an efficient in situ polymerization method. The surface immobilization was characterized by optical microscopy (OM), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, hydrophilicity, porosity, and cyclic voltammetry. The OM and SEM images showed that PNVPY formed polymer coatings and aggregated nanoparticles on the EC nanofibers, while P3HT only produced polymer coatings. Compared with pure EC mats, both the composite mats had increased thickness, higher porosity, and higher conductivity. Also, an increase in hydrophilicity was found for EC/P3HT. In vivo cytocompatibility of the undifferentiated PC12 cells showed that the EC/PNVPY and EC/P3HT scaffolds exhibited favorable cell activity, adhesion, and proliferation. Furthermore, the results of electrical stimulation experiments indicated that the EC/P3HT mats could effectively promote the proliferation of the PC12 cells more than the EC and EC/PNVPY mats. The findings suggest a positive outcome regarding the conductive polymer-modified EC/PNVPY and EC/P3HT nanofibrous mats in neural tissue engineering.

In this paper we report a novel probe based on a luminescent 23-membered [1 + 1] Schiff-base macrocyclic mononuclear Sm(iii) complex Sm-2e, originating from the dialdehyde H2Qe and 1,2-bis(2-aminoethoxy)ethane precursors, which is synthesized by the Sm(iii) ion template method. X-ray structural analyses confirm that each ten-coordinate Sm(iii) center with the coordination geometry of a distorted bicapped square antiprism is fully encapsulated by a flexible macrocyclic ligand H2L2e to form a "lasso-type" architecture, and this architecture could enable efficient energy transfer in various solvents confirmed by long lifetimes (33.5-65.2 μs) and high quantum yields (0.23-0.76%) of the Sm(iii) ion. Simultaneously, complex Sm-2e could serve as a probe for sensing organic solvents. Particularly, this complex probe Sm-2e exhibits a highly selective, rapid and sensitive response to tetrahydrofuran (THF), which is easily distinguished by a large absorption shift, even visible to the naked eye, and complete fluorescence quenching. Moreover, the limit of detection for THF is about 0.20% determined by titration experiments, and good selectivity for THF could still be realized in mixture solvents. Consequently, this colorimetric and "turn off" fluorescent probe Sm-2e could be a valuable candidate as a sensor material for sensing THF which has been rarely reported.

The intercalation and delamination processes of Ti3C2Tx are systematically investigated by using alkylammonium hydroxides (TAAOH) with different chain lengths. TAA+ cations have a key function for the intercalation reaction of Ti3C2Tx nanosheets, and the basal spacing and the crystal phase of TAA+-intercalated Ti3C2Tx at different stages are closely related to the size of the intercalated TAA+ ions, and they are hardly changed with the addition of molar equivalents of TAAOH per mole of Ti3C2Tx and the drying conditions. Moreover, the intercalation process is very rapid and it can be carried out by just 4 h treatment. TAA+-intercalated Ti3C2Tx can be delaminated into Ti3C2Tx nanosheets by hand shaking or repeated washing. By introducing a graphene oxide nanosheet suspension into the Ti3C2Tx nanosheet suspension, Ti3C2Tx/RGO fibers are firstly prepared by a wet-spinning method followed by reducing Ti3C2Tx/GO fibers in HI/CH3COOH solution. Then the Ti3C2Tx/RGO fiber is soaked in KMnO4 solution with different concentrations at room temperature, and a MnO2/Ti3C2Tx/RGO ternary hybrid fiber with good flexibility and capacitance is prepared. The MnO2/Ti3C2Tx/RGO ternary hybrid fiber electrode shows the largest volumetric capacitance of 851 F cm−3 in 1 M Na2SO4 electrolyte and good flexibility. By twisting two of these fiber electrodes together, an all-solid-state symmetric MnO2/Ti3C2Tx/RGO//MnO2/Ti3C2Tx/RGO fiber supercapacitor with PVA–LiCl gel electrolyte is assembled. It not only exhibits a volumetric capacitance of 24 F cm−3 and superior cycle stability of 92% after 10 000 cycles, but also shows outstanding flexibility and mechanical properties in which the volumetric capacitance has no obvious change after bending the supercapacitor at 90° 1000 times. Furthermore, the assembled symmetric supercapacitor shows the maximum volumetric energy density of 2.13 mW h cm−3 at a volumetric power density of 8.16 mW cm−3. This work will open a new application field of Ti3C2Tx-based fibers for new wearable energy storage devices with good energy density and flexibility.

Nucleic acid tests have been widely used for diagnosis of diseases by detecting the relevant genetic markers that are usually amplified using polymerase chain reaction (PCR). This work reports the use of a plasmonic device as an efficient and low-cost PCR thermocycler to facilitate nucleic acid-based diagnosis. The thermoplasmonic device, consisting of a one-dimensional metal grating, exploited the strong light absorption of plasmonic resonance modes to heat up PCR reagents using a near-infrared laser source. The plasmonic device also integrated a thin-film thermocouple on the metal grating to monitor the sample temperature. The plasmonic thermocycler is capable of performing a PCR amplification cycle in ~2.5 minutes. We successfully demonstrated the multiplex and real-time PCR amplifications of the antibiotic resistance genes using the genomic DNAs extracted from Acinetobacter baumannii, Klebsiella pneumonia, Escherichia coli and Campylobacter.

During the failure process, granite always exhibits strain-softening behavior and confining pressure-dependent effect. Based on triaxial cyclic loading and unloading compression tests, the evolutions of cohesive strength, internal friction angle, and elastic modulus with axial plastic strain and confining pressure were obtained. The results show that both the cohesive strength and the internal friction angle first increase and then decrease with an increase in the axial plastic strain. Meanwhile, the elastic modulus increases with an increase in the confining pressure and decreases with an increase in the axial plastic strain. Considering the evolutions of the cohesive strength, the internal friction angle and the elastic modulus, an improved strain-softening constitutive model was proposed. The proposed model was further embedded in the Fast Lagrangian Analysis of Continua (FLAC) procedure, based on which the conventional triaxial cyclic loading and unloading tests were simulated. The simulated results have shown a good agreement to the experimental results.

Understanding the mechanical behavior of rock under conditions of high temperature and pressure is critical when it comes to implementing underground coal gasification, deep disposal of highly radioactive nuclear waste, development and utilization of deep underground space, development and utilization of geothermal resources, etc. To understand the effect of confining pressure on limestone at high temperature, uniaxial and triaxial compression testing was conducted on limestone under high temperature (20–800 °C) using the MTS 815 rock mechanics testing system. Using this system, the change in the strength and deformation parameters of the limestone at varying temperature and confining pressure conditions were studied. The results show that the triaxial compression stress-strain curve of limestone at high temperatures is divided into five stages: compaction stage, elastic stage, plastic deformation stage, post-peak failure stage, and residual stage. In addition, the rock brittleness and ductility decrease as the temperature increases. The peak stress and residual strength of the limestone at high temperatures increase as the confining pressure increases, and the strength of the rock specimens decreases as the temperature increases. The internal friction angle (φ) first increases and then decreases as the temperature increases, but the relationship of the cohesive force (c) to temperature is opposite that of φ, indicating that the shear strength of limestone at high temperatures is determined by both c and φ. The elastic modulus of limestone at high temperatures increases with the increase in confining pressure and decreases as the temperature increases, and the peak strain of limestone at high temperatures increases as the confining pressure and temperature increase. The effect of temperature on the failure of limestone is not obvious, and the failure of rock specimens during uniaxial compression testing was mostly through axial splitting, while the failure of rock specimens under triaxial compression testing was mostly through shear failure. As the confining pressure increases, the fracture type of the rock specimens gradually changes from brittle tensile fracture to shear fracture, and the instability type of the rock specimen changed from the sudden instability type to the progressive failure type. Our research results are especially useful in areas where engineering is performed on rocks under high temperature.

Porphyrin-based covalent organic frameworks (Por-COF) nanosheets were vertically anchored on carbon nanotubes (CNT) with covalent connection for efficient electrocatalytic CO2 reduction reaction (CO2RR). The CNT not only acts as ideal carriers for the dispersion of Pro-COF but also facilitates electron transfer along porphyrin planes to immobilized metal active sites. As a result, covalently linked MWCNT-Por-COF-M (M: Co, Ni, Fe) display improved electrocatalytic CO2-to-CO activity and selectivity compared to pure Por-COF-M and MWCNT@Por-COF-M without covalent connection between two components. In particular, MWCNT-Por-COF-Co exhibits superior activity (FECO: 99.3%), higher partial current density and good durability in 0.5 M KHCO3 by H-type cell, while MWCNT-Por-COF-Cu exhibits the highest CH4 faradaic efficiency of 71.2% in 1.0 M KOH by flow cell. The results of HRTEM and Auger spectrum revealed that the high performance of MWCNT-Por-COF-Cu could be attributed to the generated Copper-based nanoclusters during the electrocatalytic CO2RR process.

Wetting and non-wetting liquid flow in nanoscale pores or channels is of great interest in many science and technology fields, such as biotechnology, energy storage/conversion and micro-devices. It is also of considerable significance in geosciences and geoengineering. For instance, for the geological disposal of contaminated waste understanding flow and transport in nanoporous rocks is critical for accurately evaluating potential environmental hazards. Similarly, for oil recovery from tight reservoirs, understanding flow mechanisms in nanopores may improve production forecasts and enable the development of strategies to enhance production. This paper presents a comprehensive study on wetting and non-wetting liquid flow in nanopores, including the development of a new nanoflow model and its demonstration using published findings from molecular dynamics simulations and laboratory tests. The new nanoflow model is formulated based on the general two-dimensional Navier-Stokes equations. The novel aspects include: 1) the model incorporates the parameters relating to the intermolecular interactions between the fluid and the solid wall in a nanopore, which are lacking in traditional continuum models; 2) the model contains the effects of wettability and the nanochannel’s dimension on flowrate, which are unique to nanoflows and not considered in traditional continuum models; and 3) the model is based on a two-dimensional non-Poiseuille flow model described by a set of coupled ordinary differential equations. Therefore, the numerical solutions are much easier to obtain than the partial differential equations of non-Poiseuille flow models. The classic Poiseuille flow is its limiting case. Three examples are presented to demonstrate the model’s capability. The first is the determination of the contact angle of water in hydrophobic carbon nanochannels or nanotubes using published results from MD simulations and laboratory tests. The second example uses the new nanoflow model to simulate non-wetting water flow in hydrophobic nanochannels or nanotubes, including flow in a nanoscale graphene slit representative of those present in graphene batteries for energy storage. The results obtained are compared with those obtained from MD simulations. The last example discusses the wetting or partially wetting liquid flow profiles in nanoscale pores. The three examples provide new insights into wetting and non-wetting liquid flow behaviour in nanopores.

This paper describes a tape nanolithography method for the rapid and economical manufacturing of flexible, wearable nanophotonic devices. This method involves the soft lithography of a donor substrate with air-void nanopatterns, subsequent deposition of materials onto the substrate surface, followed by direct taping and peeling of the deposited materials by an adhesive tape. Without using any sophisticated techniques, the nanopatterns, which are preformed on the surface of the donor substrate, automatically emerge in the deposited materials. The nanopatterns can then be transferred to the tape surface. By leveraging the works of adhesion at the interfaces of the donor substrate-deposited material-tape assembly, this method not only demonstrates sub-hundred-nanometer resolution in the transferred nanopatterns on an area of multiple square inches but also exhibits high versatility and flexibility for configuring the shapes, dimensions, and material compositions of tape-supported nanopatterns to tune their optical properties. After the tape transfer, the materials that remain at the bottom of the air-void nanopatterns on the donor substrate exhibit shapes complementary to the transferred nanopatterns on the tape surface but maintain the same composition, thus also acting as functional nanophotonic structures. Using tape nanolithography, we demonstrate several tape-supported plasmonic, dielectric, and metallo-dielectric nanostructures, as well as several devices such as refractive index sensors, conformable plasmonic surfaces, and Fabry-Perot cavity resonators. Further, we demonstrate tape nanolithography-assisted manufacturing of a standalone plasmonic nanohole film and its transfer to unconventional substrates such as a cleaved facet and the curved side of an optical fiber.

Crystalline and porous covalent organic frameworks (COFs) and metal-organic frameworks (MOFs) materials have attracted enormous attention in the field of photocatalytic H2 evolution due to their long-range order structures, large surface areas, outstanding visible light absorbance, and tunable band gaps. In this work, we successfully integrated two-dimensional (2D) COF with stable MOF. By covalently anchoring NH2 -UiO-66 onto the surface of TpPa-1-COF, a new type of MOF/COF hybrid materials with high surface area, porous framework, and high crystallinity was synthesized. The resulting hierarchical porous hybrid materials show efficient photocatalytic H2 evolution under visible light irradiation. Especially, NH2 -UiO-66/TpPa-1-COF (4:6) exhibits the maximum photocatalytic H2 evolution rate of 23.41 mmol g-1 h-1 (with the TOF of 402.36 h-1 ), which is approximately 20 times higher than that of the parent TpPa-1-COF and the best performance photocatalyst for H2 evolution among various MOF- and COF-based photocatalysts.

A variety of Dy3+-, Tb3+- and Eu3+-singly or doubly or triply activated NaCa4(BO3)3 phosphors for light emitting diodes applications were synthesized via a high temperature solid state reaction technique under an ambient atmosphere. These phosphors were studied by X-ray diffraction, scanning electron microscopy, photoluminescence excitation and emission spectra, Commission International de I'Eclairage chromaticity coordinates, and correlated color temperatures. The emission colors of Dy3+-, Tb3+-, and Eu3+-doped phosphors can be successfully tuned from green to yellow and then to white by appropriately changing the Tb3+ content and the excitation wavelengths. The correlated color temperatures can also be tailored from cold color to warm color. Furthermore, the energy transfer process from Dy3+ to Tb3+ in the Dy3+/Tb3+ codoped phosphors exists, which is discussed based on the luminescence spectra and energy level diagram analysis. The NaCa4(BO3)3:Dy3+, Tb3+, Eu3+ phosphors reported here demonstrate promising applications in the fields of near ultraviolet based light emitting diodes.

Designing nanostructured metal oxides (MOs) is a particularly effective approach to enhance their lithium storage properties. However, it is difficult to synthesize MOs with various nanostructures by a facile strategy. Herein, based on the Kirkendall effect, the yolk-shell, hollow, and hierarchical Fe0.8Mn1.2O3 sub-micropolyhedrons are produced by briefly adjusting the calcination temperature of the precursor. Moreover, hollow and hierarchical Fe0.8Mn1.2O3 sub-microcubes can also be synthesized by further aging the precursor and then using the same strategy. Furthermore, the formation mechanism for the above-mentioned nanostructures is carefully studied. Among all prepared Fe0.8Mn1.2O3 nanostructures, the hierarchical sub-micropolyhedrons exhibit the best lithium-ion storage performance. It can deliver an excellent discharge capacity of 1114.3 mAh g−1 after 100 cycles at 200 mA g−1 and superior rate properties (1268.8, 864.1, 698.9, 556.3, and 397.6 mAh g−1 at 0.2, 1, 2, 4, and 8 A g−1, respectively).

The precise tuning and multi-dimensional processing of covalent organic frameworks (COFs)-based materials into multicomponent superstructures with appropriate diversity are essential to maximize their advantages in catalytic reactions. However, up to now, it remains an ongoing challenge for the precise design of COFs-based multicomponent nanocomposites with diverse architectures. Herein, a metal organic framework (MOF)-sacrificed in situ acid-etching (MSISAE) strategy that enables continuous synthesis of core-shell, yolk-shell, and hollow-sphere COFs-based nanocomposites through tuning of core decomposition (NH2 -MIL-125 into TiO2 ) rate is developed. More importantly, due to the multiple active sites, fast transfer of carriers, increased light utilization ability, et al, one of the obtained samples, NH2 -MIL-125/TiO2 @COF-366-Ni-OH-HAc (yolk-shell) with special three components, exhibits high photocatalytic CO2 -to-CO conversion efficiency in the gas-solid mode. The MSISAE strategy developed in this work achieves the precise morphology design and control of multicomponent hybrid composites based on COFs, which may pave a new way in devealoping porous crystalline materials with powerful superstructures for multifunctional catalytic reactions.

The research into the road performance of coal gangue is of great significance for the consumption of coal gangue and reducing pollution. In this paper, the coal gangues were prepared by separation and crushing processes, and their gradations were also optimized. Aiming to identify the possible problems of coal gangue as a pavement base, an unconfined compressive strength test, a splitting test, a freeze–thaw test, and a drying shrinkage test of cement stabilized gangue with varying cement amounts were carried out, and the test results were compared and analyzed. The test results showed that the maximum dry density and optimum moisture content (OMC) of the optimized cement stabilized gangue and cement stabilized macadam increased with cement content. The maximum dry density and OMC of cement stabilized macadam were larger than that of cement stabilized gangue with the same cement content. The optimized 7-day unconfined compressive strength of cement stabilized gangue can meet the requirements for a secondary and lower highway base and subbase. The OMC and cement content are the critical factors affecting the compressive strength loss rate of cement stabilized gangue after freeze–thaw cycles. The smaller the OMC of cement stabilized gangue and the larger the cement content, the lower the compressive strength loss rate. With an increase in cement content, the drying shrinkage strain of cement stabilized gangue increased. The results show that a cement content of 4% is optimal for the cement stabilized coal gangue, which can be used for the light traffic base and heavy traffic subbase of class II and below highways. It provides a basis, guide, and reference for the application of coal gangue materials in a high-grade highway base.

This work presents a low-cost, large-scale nanofabrication approach that combines imprint lithography and silver doping (IL-SD) to pattern chalcogenide glass (ChG) films for realizing IR devices. The IL-SD method involves controled photodoping of silver (Ag) atoms into ChG films and selective removing of undoped ChG. For photodoping of Ag, an Ag-coated elastomer stamp is brought in contact with the ChG film and exposed to ultraviolet light, and subsequently, the Ag atoms are photo-dissolved into the ChG film following the nanopatterns on the elastomer stamp. Due to the high wet-etching selectivity of the undoped ChG to Ag-doped one, the ChG film can be precisely patterned with a spatial resolution on the order of a few tens of nanometers. Also, by controling the lateral diffusion of Ag atoms during ultraviolet exposure, it is possible to adjust the size of the final patterns formed in the ChG film. As an application demonstration of the IL-SD process, the As2 S3 -based near-infrared photonic crystals (PhCs) in the wavelength range and flexible midinfrared PhCs are formed, and their optical resonances are investigated. The IL-SD process enables the low-cost fabrication of ChG nanostructures on different substrate materials and gives a great promise to realize various IR devices.

A strategy to covalently connect crystalline covalent organic frameworks (COFs) with semiconductors to create stable organic-inorganic Z-scheme heterojunctions for artificial photosynthesis is presented. A series of COF-semiconductor Z-scheme photocatalysts combining water-oxidation semiconductors (TiO2 , Bi2 WO6 , and α-Fe2 O3 ) with CO2 reduction COFs (COF-316/318) was synthesized and exhibited high photocatalytic CO2 -to-CO conversion efficiencies (up to 69.67 μmol g-1 h-1 ), with H2 O as the electron donor in the gas-solid CO2 reduction, without additional photosensitizers and sacrificial agents. This is the first report of covalently bonded COF/inorganic-semiconductor systems utilizing the Z-scheme applied for artificial photosynthesis. Experiments and calculations confirmed efficient semiconductor-to-COF electron transfer by covalent coupling, resulting in electron accumulation in the cyano/pyridine moieties of the COF for CO2 reduction and holes in the semiconductor for H2 O oxidation, thus mimicking natural photosynthesis.

Photonic crystals (PhCs) offer the unprecedented capability to manipulate light and material interaction. This chapter reviews the recent developments of sol–gel-based PhCs and their applications. Here, the underlining optics of two-dimensional PhC slabs is explained. The dereferences of in-plane and out-of-plane coupling of PhC slabs are discussed in detail. The fabrication technologies used to produce the nanoscale structures of PhCs are discussed. Among the existing fabrication methods, the chapter focuses on the imprint lithography approach and manifests how the sol–gel materials can be adopted in the imprint lithography. Then, the processes to prepare high-refractive-index sol–gel materials, such as aluminum oxide, zinc oxide, and titanium oxide, are briefly reviewed. Furthermore, a few successful applications of the sol–gel PhCs including light extraction from LEDs and chemical detection are present.

This paper reports a new optical fiber thermometer (OFT) for temperature measurement under extreme environments, such as in molten steels. The OFT probe consists of a ceramic tube and a sapphire fiber, which is coated with a nanorod cladding layer. Installed inside the ceramic tube, the nanorod-cladding sapphire fiber can collect thermal emissions of the ceramic tube and couple the emission out of the OFT probe to a near-infrared spectrometer with minimal loss of photons. The molten steel temperature was determined by analyzing the emission spectra using a polynomial curve fitting or a machine learning-based classification algorithm.

This paper demonstrates a paper-based nucleic acid amplification test with a portable instrument. The paper-based sensor provides the functions of reagent storage, sample transportation, and DNA amplification. The compact and low-cost fluorescence detector can quantify the amplicons in real-time. The results show that the sensor can detect multiple target genes with the concentration as low as 2 X 104 copies/gL.

A simple, sensitive and effective magnetic solid-phase extraction (MSPE) technique was developed for the extraction of pyrethroid pesticides from environmental water samples, followed by gas chromatography tandem triple quadrupole mass spectrometry determination. An adsorbent of magnetic zeolitic imidazolate framework-8@deep eutectic solvent (M-ZIF-8@DES) was prepared using deep eutectic solvent coated on the surface of M-ZIF-8. The features of M-ZIF-8@DES were confirmed by material characterizations, and the results indicated that M-ZIF-8@DES has a good magnetism (61.3 emu g&minus, 1), a decent surface area (96.83 m2 g&minus, 1) and pore volume (0.292 mL g&minus, 1). Single factor experiments were carried out to investigate the effect of different conditions on the performance of MSPE. Under the optimal conditions, the developed method performs good linearity (R2 &ge, 0.9916) in the concentration range of 1&ndash, 500 &mu, g L&minus, 1. The limits of detection were in the range of 0.05&ndash, 0.21 &mu, 1 (signal/noise = 3/1). The intraday relative standard deviation (RSD) and interday RSD were less than 9.40%. Finally, the proposed technique was applied for the determination of pyrethroid pesticides in environmental water samples. This work shows the potential of DES-modified metal-organic frameworks for different sample pretreatment techniques.

This work reports a paper-based sensor technology for point-of-care nucleic acid amplification tests. The technology integrates a sensor chip and an Arduino-compatible fluorescence detector. The paper-based sensor provides the functions of reagent storage, sample transportation, and DNA amplification. The compact and low-cost fluorescence detector can quantify the amplicons in real time. The results show that the paper-based sensor can detect genomic DNA extracted from Escherichia coli with the concentration as low as 2 × 104 copies/ µL. As a diagnosis tool, the sensor has the potential to measure multiple target genes simultaneously.

This paper reports a novel nanofabrication approach that combines imprint and silver doping lithography (iSDL) to generate nanoscale patterns in chalcogenide (ChG) thin films. The iSDL approach is capable of controlling the photodoping of silver in amorphous ChG with a high spatial precision. The ChG nanophotonic devices with one-dimensional (1D) and two-dimensional (2D) periodic structures were fabricated and characterized.

This paper demonstrates a robust optical fiber thermometer (OFT) for temperature measurement under extreme environments. To date, the development of sensors for continuous temperature measurement in environments with temperatures over 1000 °C, severe electromagnetic interferences, and strong oxidizing agents has been very challenging. The proposed nano-OFT system consists of a ceramic tube, a nanorod coated sapphire fiber, and a near-infrared (NIR) spectrum analyzer for continuous measurement of molten steel temperature in furnaces. The nanorod layer functions as an effective cladding material for the sapphire fiber to sustain a reliable transmission of NIR thermal emissions. The thermal radiation from the ceramic tube's tip was coupled out of the nano-OFT probe via the sapphire fiber and measured using the NIR spectrometer. The NIR emissions were analyzed using a convolution neural network to determine the probe temperature. Our results show that the nano-OFT probe can measure furnace temperature in the temperature range from 1,000–1,650 °C, with the error percentage as low as 0.5 %. The nano-OFT system can be employed by the steel industry to monitor steel temperature continuously, and thus enhance steel production efficiency and reduce energy consumption.

Bare fiber Bragg grating (FBG) is packaged by thermal conductive materials and to be used as a temperature sensor. In the oil bath calibration of the temperature coefficient of the FBG temperature, it is difficult to accurately synchronize the single point temperature measurement and the simultaneously record FBG central wavelength using different devices. An automatic, fast and high precision calibration method for temperature coefficient of FBG temperature sensor is proposed. The experimental results show that the temperature coefficient obtained by the proposed method can accurately measure the temperature, and the calibration process is fast and avoids the error caused by manual recording and formula derivation. The system is suitable for rapid calibration of mass-produced FBG sensors.

Nanoporous Ni Cu P amorphous alloy (NPA NiCuP) and nanoporous Ni Cu crystalline alloy (NP NiCu) have been prepared by potentiostatic etching of copper from the electroless Ni Cu P and Ni Cu alloy platings, respectively. The results of X-ray Diffraction (XRD), Energy Dispersion Spectrum (EDS) and Scanning Electron Microscopy (SEM) indicate that the NPA–NiCuP alloy is amorphous structure and shows a porous network structure with the pore size of 100–300 nm. The electrocatalytic oxidation of hydrazine in alkaline media is investigated by cyclic voltammetry (CV) and double potential step chronoamperometry (DPSCA). The results suggest that the proton diffusion coefficient of redox species and the reaction rate constant of the NPA–NiCuP alloy electrode in KOH solution are higher than those of the smooth electroless Ni Cu P amorphous (SA–NiCuP) and NP–NiCu alloy electrodes. In addition, the NPA–NiCuP electrode has higher anodic oxidation peak current density and lower onset oxidation potential of hydrazine in KOH solution than the SA–NiCuP and NP–NiCu electrodes. Finally, the CV measurement suggests that the NPA–NiCuP electrode has a relatively stable redox behavior.