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Herein, we present a facile reinforcement method for the large-scale fabrication of highly flexible, mechanically stable, temperature-resistant ceramic lightweight membranes based on the cross-linked assembly of zirconia-silica (ZrO2-SiO2) nanofibrous and montmorillonite (MMT) nanosheets through electrospinning and a subsequent calcination process. The resulting MMT@ZrO2-SiO2 membranes exhibit high flexibility with a bending rigidity of 0.2 cN mm-1, robust mechanical performance with a tensile strength of up to 1.83 MPa, robust fire resistance, and temperature-invariant mechanical stability from -196 to 1000 °C. The thermal superinsulation with a thermal conductivity as low as 0.026 W m-1 K-1 and the improved mechanical strength can be attributed to the cross-linked interfacial interaction between the ZrO2-SiO2 nanofibers and the MMT nanosheets. Additionally, a firefighter uniform with MMT@ZrO2-SiO2 membranes inside features a superior thermal protective property up to the A2 level (combined flame and radiant exposure) and an excellent fire resistance of up to 1000 °C, which is ideal for next-generation firefighter uniform manufacturing.

As a new type of nanomaterials, the gold nanoclusters (AuNCs) perform many special physical and chemical properties, such as large Stokes shift, relatively simple preparation, good water solubility, low toxicity, and good biocompatibility, which make them show infinite potential in various fields, especially in cancer treatment. In recent years, great progress has been made in the preparation, functionalization, and biomedical applications of the AuNCs. In this article, the latest research progress and synthesis methods of the AuNCs have been summarized, emphasizing the preparation using the “bottom- up” synthesis strategy. Furthermore, we introduced the in vivo pharmacokinetic performance of the AuNCs. In the last part, we exemplified the applications of the AuNCs in biomedicine, including photothermal therapy (PTT), bioimaging, drug delivery, and radiotherapy sensitization, which further confirmed the great potential of the AuNCs in tumor treatment.

Ceramic membranes are attractive for thermal management applications due to its lightweight and ultralow thermal conductivity, while it is indispensable to address the long-standing obstacle of its poor mechanical stability and degradation under thermal shock. In this work, a series of the organic polymer template-modulated yttria doped zirconia (YDZ) nanofibrous membranes with lightweight, superior mechanical and thermal stability are developed through a cost-effective, scalable sol-gel electrospinning and subsequent calcination method. The YDZ membranes demonstrate excellent flexibility and foldability, which can be attributed to the tetragonal phase and small crystallite size of the YDZ fibers due to the presence of yttria. Besides, the fibrous size, grain size, mechanical and thermal stability of YDZ nanofibrous membranes could be tailored by varying the species and molecular weight of polymer template. The remarkable performances are obtained through the poly(vinyl pyrrolidone) (PVP) template YDZ nanofibrous membranes, featuring the superior tensile strength up to ∼ 4.82 MPa, excellent flexibility with bending rigidity ∼ 26 mN, robust thermal stability up to 1,200 °C, ultra-low thermal conductivity of 0.008–0.023 W·m−1·K−1 (25–1,000 °C), and excellent flame retardancy with tolerance of flame up to 1,000 °C. The remarkable properties can be attributed to the smaller fibrous size, and higher grain size resulting from PVP template. This robust material system is ideal for thermal superinsulation with a wide range of uses from energy saving building applications to spacecraft.

The density, conductivity, and viscosity of the 1,3-dimethyl-2-imidazolinone and lithium nitrate (DMI– LiNO3) solvated ionic liquid were measured as a function of temperature. Additionally, the electrochemical mechanism and electrodeposition of neodymium from the DMI–LiNO3 solvated ionic liquid were investigated. Cyclic voltammetry results indicate that the electrochemical reduction of Nd(III) is irreversible and proceeds via one-step with three-electron transfer, which is controlled by diffusion with a diffusion coefficient of 5.08×10−8 cm2/s. Energy- dispersive X-ray spectrometry and X-ray photoelectron spectroscopy data confirm that the electrodeposit obtained after electrodeposition at −4 V (vs Ag) using the DMI–LiNO3–Nd(CF3SO3)3 solvated ionic liquid contains metallic neodymium.

This paper proposes a new type of energy absorber with combined shrinking circular tubes for a high-speed train. An impact experiment is conducted to investigate the dynamic crushing performance of this energy absorber with combined shrinking circular tubes. The results show that the combined tubes experience steady dynamic shrinking deformation. Finite element (FE) models of the energy absorber are then developed, and the dynamic crushing forces are in good agreement with the impact test. A theoretical solution for the dynamic shrinking crushing load is derived. Based on the validated FE models, the effects of the friction coefficient, wall thickness and die radius on the dynamic crushing force and energy absorption are investigated. An increase in the wall thickness leads to a substantial growth in the maximum crushing force (Fmax) and specific energy absorption (SEA), but the growth rate of Fmax is much larger than that of the SEA as the wall thickness increases. In addition, comparing theoretical and FE results demonstrates that predictions of the dynamic steady-state forces for the combined shrinking circular tubes with different friction coefficients, wall thicknesses (t) and die radius (Rdie) are satisfactory. Finally, to improve the crashworthiness of the expanding circular tubes, Sobol’ sensitivity analysis is employed to analyze the effects of the design parameters (t and Rdie) on the objective responses (SEA and Fmax) using the Kriging model. A Pareto front of double optimization objective SEA and Fmax was obtained after being optimized by multiobjective particle swarm optimization (MOPSO). The results show that SEA and Fmax are positively correlated, and a balance between the SEA and Fmax was obtained at optimal point C (SEA = 13.09 kJ/kg, Fmax = 581.11 kN).

The reasonable design and preparation of cheap, Earth-abundant, efficient, and durable heterogeneous electrocatalytic materials are a probable solution to the key problems of energy shortages and e...

Lanthanide (Ln) metal–organic frameworks (Ln-MOFs) have attracted attention in anti-counterfeiting and white light-emitting diodes (WLEDs) due to their high quantum efficiency, long lifetimes, and characteristic linear spectrum. However, Ln-MOFs have some disadvantages, such as harsh luminescence modulation, low transparency, and poor film formation. In this study, Ln-MOF (Ln = Eu and/or Tb)-modified TEMPO-oxidized cellulose nanofibrils were employed for preparing transparent nanopapers and luminescence modulation. These luminescent nanopapers achieved an excellent light emission color tuning from green, yellow, and red under 365 nm excitation, while 254 nm radiation on these nanopapers only emitted characteristic pink light. Thus, the luminescent nanopapers combined color-tuning and photo-switching properties through the control of Eu³⁺/Tb³⁺ molar ratio and excitation wavelength (λEₓ at 365 and 254 nm), respectively, which greatly improved them for anti-counterfeiting applications. In addition, Ln-MOFs endowed these nanopapers with excellent optical haze (>90%), such that softening of white light from WLEDs was realized in 254 nm-driven UV-LED chips, corresponding white light with good color quality [Commission International de I’Eclairage coordinates, correlated color temperature, and color-rendering index of (0.34, 0.36), 5536 K and 86, respectively].

Separation or purification is one of the difficult problems in the petrochemical industry. To help solve the difficulty of separation or purification for C2H2/CO2 and C2Hn/CH4 in the chemical industry, we synthesized a new metal-organic framework (MOF), [Ni(dpip)]·2.5DMF·H2O (1), by a bipyridyl-substituted isophthalic acid ligand. The MOF includes two types of one-dimensional (1D) tubular channels with different sizes and porous environments. The unique tubular channels lead to not only remarkable gas sorption capacity of C2H4, C2H2, and CO2, but also good selectivity for C2H2/CH4, C2H2/CH4, CO2/CH4, and C2H2/CO2, as demonstrated by single-component sorption isotherm results, ideal adsorbed solution theory calculations, and dynamic breakthrough curves. Grand canonical Monte Carlo (GCMC) simulation reveals preferential adsorption sites in the MOF for CO2, C2H2, and C2H4. The MOF also exhibits an obvious size-selective absorption effect on vapor molecules.

The chiral deformation of a conventional helical actuator is unidirectional in each activation (stimuli-on) process and in each recovery (stimuli-off) process, which means that the twisting direction remains the same regardless of the nature of deformation (either winding or unwinding or helix-inversion). In these cases, a complete stimuli-switching cycle is necessary for the realization of a bidirectional helical deformation process that comprises a reversal of twisting direction. Here, we achieved bidirectional and even multi-directional helical shape evolution in each stimuli-on (or off) process. The strategy relies on, on one hand, asymmetrically crosslinking and/or elongating the two sides of a photocrosslinkable liquid crystal polymer (LCP) monolith, and on the other hand, tailoring the uniaxially aligned polymer strip to form an off-axis mesogen orientation. We obtained a wide variety of helical actuators capable of reversing their twisting directions by only cooling (or heating). The mechanisms of these various chiral deformation-reversal behaviours and the two observed reversals of the twisting direction during cooling have been elucidated.

In this paper, gas sensing characteristics of Boron-doped graphene oxide(B-GO) are presented firstly. In order to detect the optimal value of boron doping, different amounts of boron (5-30 wt%) are adopt in the doping process. The results of sensing test revealed that at room temperature (20 °C) and humidity (30%), 15 wt% B-GO has the optimal sensitivity to NH3. Meanwhile, the detection response and recovery time of B-GO gas sensor to NH3 are relatively short. Theoretical models of graphene and B-doped graphene are established, and energy change in the gas-adsorption of NH3 on the graphene oxide or B-doped graphene oxide is calculated. The enhanced sensing performance was ascribed to the B-doping and the formation of chemical bonds between boron and NH3.

Developing highly efficient and low-cost electrocatalysts for the hydrogen evolution reaction (HER) in neutral media is crucial but still a significant challenge on account of the sluggish multistep reaction kinetics involved. Theoretically, constructing a metal/metal hydroxide interface with a metal hydroxide acting as a water dissociation promotor and a metal as the subsequent hydrogen adsorption site is expected to accelerate the HER kinetics in neutral media. We found that the intercalation of tungstate into Ni(OH)2 can tune the electronic structure of the Ni/Ni(OH)2 interface, decrease the energetic barrier for the Volmer step, and thus optimize the HER performance of Ni/Ni(OH)2 hybrid. Herein, a heterostructured Ni/Ni(OH)2 nanosheet array on Cu foam is designed and constructed via a simple hydrothermal and subsequent plasma reduction strategy. The HER performance can be further enhanced by assembling tungstate-intercalated Ni/Ni(OH)2 hybrid nanosheets on Cu2O nanotube arrays, exhibiting a low overpotential (39 mV @ 10 mA cm−2) and excellent stability (48 h).

The discharge of excessive metal ions and anions into water bodies leads to the serious pollution of water and environment, which in turn has a certain impact on industry, agriculture, and human life. Because of the unique advantages of luminescent metal-organic frameworks (LMOFs), they have been successfully explored as various fluorescent probes to quickly and effectively detect these pollutants. This perspective not only introduces the design strategy and classification of LMOFs, especially the construction methods of water-stable LMOFs, but also reports the latest progresses in some LMOFs between 2016 and 2020 as well as expounds the mechanisms of LMOFs for detecting anions and cations. Moreover, the luminescence properties of LMOFs are related to the selection of metal ions, the structure of organic ligands, the pore size, and the interaction of guest molecules. Finally, the further development of LMOFs is summarized and prospected in this field.

Developing efficient electrocatalysts for the neutral oxygen evolution reaction (OER) is important but still challenging. Herein, by combining density functional theory calculations and experiments, we have demonstrated that the decoration of RuO2 can effectively accelerate the OER kinetics of Co3O4 in neutral electrolyte. High activity (365 mV at 10 mA cm−2) and decent stability (up to 100 h) are achieved by RuO2-decorated Co3O4 in 1 M PBS electrolyte.

Transition metal phosphides (TMPs) have been reported as efficient pre-catalysts for the oxygen evolution reaction (OER) in alkaline media. In situ generated metal oxyhydroxides on the surface of TMPs serve as real active sites. However, the reconstruction of most of the reported TMPs is incomplete and the active components cannot be fully used. Herein, hollow nanostructured Ni5P2/FeP4 nanoboxes (NiFeP NBs) are designed and synthesized as pre-catalysts. During the OER, the NiFeP NBs deeply reconstruct into low-crystalline and ultrathin NiOOH/FeOOH nanosheet assembled nanoboxes (NiOOH/FeOOH NBs). In situ Raman spectroscopy and ex situ characterization studies provide evidence that the hollow nanostructure facilitates the deep reconstruction of NiFeP NBs. Benefiting from the hierarchical hollow structure, the abundant interface between NiOOH and FeOOH, and plentiful defects, the reconstructed NiOOH/FeOOH NBs exhibit superior OER activity and excellent stability. Density functional theory (DFT) calculations reveal that the Fe–Ni dual sites in the NiOOH/FeOOH interface may be the possible active sites.

A novel two-dimensional coordination polymer with a negatively charged framework named {[(CH3)2NH2][Zn2(L)2]·DMF}n (1) was solvothermally synthesized via the assembly of Zn(II) ions with the organic ligand H3L (2-(3,5-dicarboxylphenyl)-6-carboxyl-benzimidazole). 1 was characterized by IR spectroscopy, thermogravimetry, single-crystal, and powder X-ray diffraction methods. 1 possesses a 1D rectangle channel decorated by abundant uncoordinated imidazole N atoms and carboxylate O atoms, and is a better CO2 adsorbent and promising CO2/CH4 selective material, suggesting potential application in gas separation. Moreover, 1 can also serve as a multi-responsive sensing material for detecting nitrobenzene (NB) and Cr2O72−via a luminescence quenching effect with a low detection limit, and the mechanisms of the quenching effect and sensing properties of 1 are discussed in detail.

Two new metal–organic frameworks (MOFs), formulated as [Cd3(L)2(H2O)2]·2H2O (1) and [Zn2(L)(OH)(H2O)]·2DMA (2, DMA = N,N-dimethylacetamide), were first constructed via an unsymmetrical N-heterocyclic 5-((4-carboxypyridin-2-yl)oxy)isophthalic acid (H3L) ligand. Then, a proportion of the Zn(II) ions of 2 were substituted by fine-tuning the contents of Co(II) ions to obtain two new isomers, Co1-MOF 2 and Co2-MOF 2, the successful doping of which can be proved by PXRD, IR spectra, ICP, XPS, and SEM. The luminescent experiments suggested that complex 1 should be a good detector for detecting Fe3+ and Cr2O72− ions. More remarkably, the Co-rich MOF materials have increased gas capture for CO2 and CH4 compared to that of the Co-free isomer 2, and the absorption amount of CO2 and CH4 may rise with the increasing content of Co(II) ions in the system at higher pressure and lower temperature.

A new 3D luminescent Ba-organic framework {[Ba3L2(NMP)2(H2O)2]·2NMP·H2O}n (1) was first synthesized based on Ba(II) and a triangular-shaped bridging rigid ligand, namely 1,3,5-tris(4-carboxyphenly)benzene (H3L), via solvothermal reaction (NMP = N-methyl pyrrolidone), thereby forming a stabilized network including a one-dimensional (1D) infinite rod-like helical metal chain. 1 may be explored as a recyclable heterogeneous catalyst for the efficient fixation of CO2 to form serviceable cyclic carbonate since 1D channels remain decorated with abundant open metal sites (OMSs), and the catalytic efficiency of 1 was up to 98% for 1-bromo-2,3-propylene oxide. Simultaneously, the luminescence sensing shows that 1 has excellent response and sensitivity towards pollutants such as Fe3+, Cr2O72−, CrO42−, and [Fe(CN)6]3− ions. Moreover, 1 exhibits the particularly selective sorption towards the Congo red (CR) dye. Consequently, this study may provide a facile synthetic route for the construction of multi-functional Ba-MOF materials.

Assembly via 1,4-benzenedicarboxylate linker and Zn2+ ions afforded a new MOF containing novel [Zn4F4] cubane cores, showing excellent C2H2 separation from C2H2–CO2 and C2H2–CH4 mixtures.

Three isostructural lanthanide metal–organic frameworks (Ln-MOFs), {[Ln(L)(H2O)2]·H2O}n (M-Ln, Ln = Eu/Tb/Dy), were prepared with a flexible 3,5-(4-carboxybenzyloxy) benzoic acid (H3L) ligand and lanthanide ions by a solvothermal method. M-Ln are two-dimensional (2D) grid layer-stacking frameworks. M-Eu exhibits excellent chemical stabilities against organic solvents and shows strong luminescence. The experimental results indicated that M-Eu could be used as an ideal fluorescent probe to detect nitrobenzene (NB) in different solvents with a lower detection limit. M-Eu can also be used as a pH sensor because of its superior water stability. Furthermore, M-Eu and M-Tb show unique strong luminescence properties with high absolute quantum yields. The quantum yields can even reach up to 11.8% and 60.5%, respectively. Simultaneously, various kinds of heterometallic doped M-EuxTb1−x MOFs were acquired by tuning the ratios of Eu3+/Tb3+ ions, showing the unique color changes from red, orange-red, orange, orange-yellow, light yellow, yellow to green.

A new series of isomorphic lanthanide metal–organic frameworks (Ln-MOFs), {[Ln2(L)3·DMF·H2O]·DMF·H2O}n (denoted as 1-Ln, Ln = Eu, Gd, Tb or EuxTb1−x), were constructed using the 4′-(1H-1,2,4-triazol-1-yl)-[1,1′-biphenyl]-3,5-dicarboxylic acid (H2L) ligand and Ln3+ ions under solvothermal conditions. 1-Ln shows a binodal (3,3,8)-connected three-dimensional (3D) framework based on a π-conjugated and uncoordinated Lewis basic triazolyl ligand. Then, six two-color doped 1-EuxTb1−x and the tri-metallic doped 1-Eu0.01Gd0.6015Tb0.3885 with white light emitting MOFs were fabricated by doping diverse concentrations of Eu3+, Tb3+ and Gd3+ ions. More interestingly, 1-Eu0.01Gd0.6015Tb0.3885 has a higher quantum yield (36.49%). Meanwhile, 1-Ln shows excellent performance in fluorescence sensing (Ksv = 1.5143 × 104 M−1) and anticounterfeiting applications.

Owing to perovskite possessing the outstanding optoelectronic properties, perovskite-based solar cells show prominent performance. The stability of perovskite-based solar cells hampers the progress of commercialization, so it is important to understand the microstructure mechanism of perovskite degradation under the humidity and oxygen environmental conditions. In this study, a meaningful Debye-type dielectric relaxation was observed under water vapor and oxygen co-treatment conditions. Interestingly, the relaxation was not observed under water vapor or oxygen treatment individually. This new dielectric relaxation is identified as a direct result of dipole jump, and its activation energy was measured to be 630 ± 6 meV. According to photoelectron spectroscopy and 13C nuclear magnetic resonance data, we suggest that the dipoles are formed by CH3NH3+ (MA+) and superoxide (O2-), which originate from the distorted crystal lattice and water vapor-weakened hydrogen bonds of Pb-I cages. In addition, the activation energy fitted by dielectric relaxation might be the energy of ion migration. This study contributes to understanding the mechanism of perovskite degradation from the view of microstructure relaxation and evolution, and also provides a method for the analysis of ion migration energy.

A new strategy incorporating three sequential treatments—selective molecular pre-masking, surface modification, and unmasking—is proposed for pore-size-dependent control of the surface properties of porous carbon materials. The method was experimentally validated using wide-pore-selective hydrophilization. n-Nonane was physically adsorbed for pre-masking, followed by room-temperature ozonation for surface modification. This process was used to introduce surface functional groups into wide pores, while leaving narrow pores intact. This study facilitates the development of new porous carbon materials with different surface properties that depend on pore size. This flexible strategy can be employed in conjunction with various molecular masking agents and surface-modification methods.

Two new different metal–organic frameworks (MOFs) [Ba(L1)(H2O)2]n·nH2O (MOF 1) and [Ba(L2)(H2O)2]n·0.5nDMF·0.5nH2O (MOF 2) were yielded by the assembly of oxygen-friendly Ba(II) ions and two similar linkers, namely 2-(imidazol-1-yl)terephthalic acid (H2L1) and 2-(1H-1,2,4-triazol-1-yl) terephthalic acid (H2L2). Single-crystal X-ray diffractions (XRD) indicate that MOF 1 is a new three-dimensional (3D) stacking dense network formed by the one-dimensional (1D) rod-shaped chains and L1 linkers, whereas MOF 2 presents a 3D nanotube porous framework with cylindrical tunnels based on the 1D loop chains as the secondary building units (SBUs) by replacing the imidazole group in H2L1 with the triazole group in H2L2. As a result, MOF 2 has a higher density of active sites and Lewis acid sites in the porous surface of nanotube than MOF 1. Thereby, the CO2 capture and separation capacity of MOF 2 is great higher than that of CH4 at 298 K.

To help address efficient separation of CH light hydrocarbons and CH/CO in the chemical industry, the self-assembly via an azolate-carboxylate ligand and Co(II) ion gave rise to a new porous MOF material, [Co(btzip)(Hbtzip)]·2DMF·2HO () (Hbtzip = 4,6-bis(triazol-1-yl)isophthalic acid). In the MOF, the pores are modified by rich uncoordinated triazolyl Lewis basic N atoms and acidic -COOH groups, which strengthen interactions with CH hydrocarbons and CO molecules, leading to high adsorption amounts for CH CH, CH, and CO and remarkable separation efficiency for CH-CH, CO-CH, and CH-CO mixtures, as confirmed by breakthrough experiments on the realistic gas mixtures. The MOF also reveals outstanding selective adsorption ability for benzene/toluene, methanol/1-propanol, methanol/2-propanol, and 2-propanol/1-propanol isomers. Molecular simulations disclose the different adsorption sites in the MOF for various adsorbates.

Tuning the emissive color changes of lanthanide (Ln) complexes is an important and appealing project for promoting the applications of Ln-complexes. A solvothermal reaction of 4-cyano-3-methylbenzoic acid (HL) and Ln(NO3)3·6H2O affords three isostructural Ln-complexes [Eu(L)3(H2O)2]n (1-Ln) (Ln = Eu, Gd and Tb) with one-dimensional chain structures. 1-Eu and 1-Tb show bright red and green emissions with absolute quantum yields of 3.06% and 11.96%, respectively, and the energy transfer was analyzed in detail through combined calculations. Interestingly, a series of heterometallic doped 1-TbxEu1-x coordination polymers were also obtained by mixing different ratios of Eu3+ and Tb3+ ions, which possess continuous luminescent color changes from green to yellow, orange and red. In addition, 1-Eu exhibits high quenching efficiency and low detection limit (∼10-4 M) for the simultaneous sensing of MnO4-, CrO42- and Cr2O72- ions in water.

Simultaneous attainments of high conductivity and superior catalysis are major challenges for amorphous electrocatalysts in carbon dioxide electroreduction at high overpotential. In this study, one protocol is first demonstrated to drive the shell amorphization of nanoporous Ag-Bi (a-NPSB) catalyst with the spatially interconnected ligament during the initial stage of CO2ER. This newborn a-NPSB bestows the outstanding catalysis, evidenced by a Faradaic efficiency of 88.4% for formate production at -1.15 V vs RHE, specific current density of 21.2 mA cm-2, and mass specific current density of 321 mA mg-1. The unique catalysis is considered as the collective contribution of the conductive ligament internally and amorphous Bi2O3 shell with about 3.2 nm thickness externally. Simultaneous obtaining of the conductivity of inner metals and catalytic activity of the amorphous shell will pave a new avenue for designing a robust electrode during electrochemical reaction.

This work explores mechanical properties, structural evolution, and mechanism of creep-life enhancement for widely used P9 heat-resistant steel. The 17-year-on-site used P9 alloy exhibit a higher tensile strength and a smaller elongation than the new P9 alloy from room temperature to 700 °C. The P9 alloy also displays a typical ductile feature with a significantly necking profile. The P9 alloy shows phase transformation sequences of α-Fe (bcc) → A c 1 ∼ 858 ° C α + γ -Fe (bcc + fcc) → A c 3 ∼ 894 ° C γ-Fe (fcc) upon heating and γ-Fe (fcc) → M s ∼ 352 ° C martensite (bct) → M f ∼ 300 ° C martensite (bct) upon cooling. The new P9-alloy tube mainly contains ∼73.5% ferrite phase (α-Fe) and ∼26.5% carbide M3C. However, the used P9-alloy tube shows four crystalline phases including ∼45.9% ferrite, ∼14.5% martensite, ∼37.5% cementite (M3C) and ∼2.7% carbide M23C6. The creep test indicates that the used P9-alloy tube has a longer creep-life (or better anti-creep ability) than the new tube. Activation energies of atomic diffusion for the new and used tubes are respectively 252.45 and 345.87 kJ/mol, indicating a decreased diffusion capability in the used tube. This work suggests that martensite laths, lath boundaries, and precipitates (such as carbides) play important roles to inhibit creep-deformation in the P9-alloy steel.

Electrochemical carbon dioxide reduction meditated by metallic catalysts suffers from restricted selectivity and competition from hydrogen evolution, which sensitively depends on ambiguous contributions of alloying and strain state in bimetallic catalysts. Herein, nanoporous Au-Sn (NPAS) containing trace tin solute in Au lattices is delicately designed to convince real strain effect, while eliminating other undesirable factors, such as alloying, crystal facets and surface composition. Compared with nanoporous gold (NPG), the NPAS with a solute strain of ∼2.2 % enables more efficient CO2-to−CO conversion, with an efficiency as high as 92 % at -0.85 V versus reversible hydrogen electrode (vs. RHE), and the high activity can retain for more than 8 h. The combination of HRTEM and surface valence band photoemission spectra reveals that the tensile strain on the surface of 3D nanoporous structure promotes the catalytic activity by shifting up the d-band center and strengthening the adsorption of key intermediate *COOH. A small amount of Sn solute in the nanoporous alloy can prevent ligament coarsening effectively and improve the electrochemical stability.

The oxidation behavior of a newly designed Co–Ni-based alloy with varied addition of Ti (1.4 and 2.1 wt.%, hereafter referred as 1.4Ti and 2.1Ti alloys) was explored in air at 900 °C. It is found that an outer oxide layer composed of CoO, an intermediate oxide layer composed of intermittent TiO2 plus continuous Cr, W-rich oxides, and an inner oxidized region composed of Al2O3 were formed on the surface of 1.4Ti alloy, whereas the oxide structure of 2.1Ti alloy was composed of CoO as the outer oxide layer, continuous TiO2, Cr2O3, and WO3 as intermediate oxide layer, and Al2O3 as the inner oxidized region. With increasing Ti content, continuous TiO2 films formed in the intermediate oxide layer, which would lead to the formation of compact Cr2O3 and improved oxidation resistance after 100 h oxidation at 900 °C. These observations indicated that Ti addition can improve the high-temperature oxidation resistance of Co–Ni-based alloys.

Novel main-chain liquid crystalline Diels-Alder dynamic networks (LCDANs) were prepared that exhibit unprecedented ease for actuator programming and reprocessing compared to existing liquid crystalline network (LCN) systems. Following cooling from 125 °C, LCDANs are deformed with aligned mesogens self-locked at room temperature by slowly formed Diels-Alder (DA) bonds, which allows for the formation of solid 3D actuators capable of reversible shape change, and strip walker and wheel-capable light-driven locomotion upon either thermally or optically induced order-disorder phase transition. Any actuator can readily be erased at 125 °C and reprogrammed into a new one under ambient conditions. Moreover, LCDANs can be processed directly from melt (for example, fiber drawing) and from solution (for example, casting tubular actuators), which cannot be achieved with LCNs using exchangeable covalent bonds. The combined attributes of LCDANs offer significant progress toward developing easily programmable/processable LCN actuators.

This paper presents an investigation of the crashworthiness of expanding circular tube energy absorbers with a cylindrical anti-clamber under eccentric loading for subway vehicles. A finite-element model of energy absorbers is created and validated by two quasi-static experiments, and the strain rate sensitivity is evaluated using standard coefficients of the Cowper-Symonds constitutive model. A parametric study is performed using the validated finite-element models. It is found that the eccentric collision of two energy absorbers has a significant effect on their crashworthiness and leads to a decrease in the specific energy absorption (SEA) and an increase in the peak crushing force (PCF). The structural parameters of the energy absorber, including the wall thickness t, conical angle α, and punch radius rp, have a significant effect on its crashworthiness under different eccentric distances. Sobol sensitivity analysis is employed to analyze the effects of the design parameters (t, α, and rp) on the objective responses (EA and PCF). The results show that the design variables t and α have a greater effect on the sensitivity of the EA and PCF functions for the eccentric distance of h = 0 and 40 mm. The interaction between punch angle α and punch radius rp has significant effect on EA. To improve the crashworthiness of the expanding circular tubes, a multi-objective optimization is applied to achieve the maximum EA and minimum PCF values, and weight factors are introduced to investigate the crashworthiness optimization under single-eccentric loading and multiple-eccentric loading. The optimization solutions of the expanding circular tubes under different single-eccentric loadings have considerable implications. For multiple-eccentric loading, the results show that the crashworthiness of the expanding circular tube energy absorber can be better balanced.

The development of appropriate catalysts with relatively low cost, good selectivity and excellent stability is one of the major issues in electrochemical reduction of CO2. In this work, an efficient electrocatalyst was fabricated via ultra-small Co3O4 nanoparticles encapsulated within the tip of carbon nanotubes, denoted as Co/CNTs. Benefiting from the synergistic effects of highly active Co3O4 nanoparticles and well-graphitized carbon nanotubes, Co/CNTs exhibited remarkable performance in CO2 electroreduction. In a conventional H-type cell, CO with a 90% faradaic efficiency and 20.6 mA cm−2 partial current density was obtained at only −0.7 VRHE cathode potential with 40 hour stability. Upon switching to a gas-diffusion device, the CO partial current density could reach as high as 232.6 mA cm−2 with >80% faradaic efficiency, which might be even comparable to that of state-of-the-art CO2 electrocatalysts. Our work could also provide a new strategy for developing non-noble metal catalysts for CO2 electroreduction.

A low-temperature and time-efficient plasma reduction strategy is developed to accelerate the hydrogen evolution reaction (HER) and overall water splitting performance of Co(OH)2. Superior HER activity (a small overpotential of 35 mV at 10 mA cm−2) and excellent overall water splitting performance (1.48 V at 10 mA cm−2) are achieved.

In this study, two new monometallic organic frameworks (MOFs), namely {[Zn1.5L(NMP)(H2O)]·H2O}n (1) and {[Pb2L2(H2O)2]·H2O}n (2), were synthesized for the first time by a new bifunctional N,O-containing 2-(1H-tetrazol-5-yl)terephthalic acid (H2L) ligand. Then, based on the HSAB principle, another porous Pb–Zn heterometallic organic framework (HMOF), namely {[PbZn0.5L(H2O)]·0.5NMP·H2O}n (3), was successfully obtained for the first time by combining Pb(II) and Zn(II) ions with H2L. The MOFs 1 and 2 are 3D densely packed frameworks, whereas the HMOF 3 is a porous 3D framework (28.9% porosity) with 1D open channels modified by Lewis basic sites (exposed N atoms) and Lewis acidic sites (unsaturated bimetallic sites). The HMOF 3 has a strong boiling water/acid–base resistance (pH = 2–12) and shows an enhanced high-efficiency catalytic effect for CO2 conversion (98%) under ambient temperature and pressure conditions. In addition, fine color regulations of the MOFs were successfully realized by doping different kinds of metal ions into them. This study aims to provide a new way and field of vision for the construction of HMOFs and their multi-functional materials.

Extrusion temperature can significantly influence grain size, the shape of second phase particles and the dislocation distribution of Mg alloys. In this study, the effects of extrusion temperatures ranging from 250 to 400 °C on the microstructure, mechanical properties and corrosion resistance of a Mg-Al-Ca alloy with 1.61 wt.% Al and 1.76 wt.% Ca (Mg-1.61Al-1.76Ca) were investigated. The results showed that the size of grains and phases increased with an increase in extrusion temperature; the yield strength and ultimate tensile strength values decreased with an increase in temperature, while the fracture elongation increased initially (up to 300 °C) and decreased thereafter with an increase in temperature. Under test, the extruded alloy exhibited some evidence of corrosion at 250 °C, while extrusion at 300 °C demonstrated better corrosion resistance. Thus, the 300 °C extruded alloy possessed the optimum comprehensive performance because of the relatively small grains, fine second phase particles and fewer dislocations.

Carbon dioxide electroreduction provides a useful source of carbon monoxide, but comparatively few catalysts could be sustained at current densities of industry level. Herein, we construct a high-yield, flexible and self-supported single-atom nickel-decorated porous carbon membrane catalyst. This membrane possesses interconnected nanofibers and hierarchical pores, affording abundant effective nickel single atoms that participate in carbon dioxide reduction. Moreover, the excellent mechanical strength and well-distributed nickel atoms of this membrane combines gas-diffusion and catalyst layers into one architecture. This integrated membrane could be directly used as a gas diffusion electrode to establish an extremely stable three-phase interface for high-performance carbon dioxide electroreduction, producing carbon monoxide with a 308.4 mA cm−2 partial current density and 88% Faradaic efficiency for up to 120 h. We hope this work will provide guidance for the design and application of carbon dioxide electro-catalysts at the potential industrial scale., Here the authors deploy Ni single atom-decorated carbon membranes as integrated gas diffusion electrodes to construct an extremely stable three-phase interface for CO2 electroreduction, producing CO with a partial current density of 308.4 mA cm–2 and a Faradaic efficiency of 88% for up to 120 h.

Bimetallic electrocatalysis with its superior performance has a broad application prospect in oxygen evolution reaction (OER), but the fundamental reason for improving the performance is still cramped. Three comparable two-dimensional (2D) metal–organic frameworks (MOFs) were designed and synthesized to explore the underlying mechanism. Among the examined 2D MOFs, CoFe-MOF exhibited the best OER performance compared with Co-MOF and CoNi-MOF. The proposed model of bimetallic and monometallic electrocatalysts affecting their OER performance can help to explore precise structure–performance relationships for a rational catalyst design at the atomic/molecular levels and understand the related catalytic mechanisms as well.

Single-crystal-to-single-crystal (SCSC) transformation has been demonstrated to provide an ideal platform to explore the formation process of chemical bonds, which is conducive to making function-oriented crystal synthesis a reality. A solvent as a ligand or a structure-directing agent plays a significant role in the structural formation of coordination polymers (CPs), and its removal/adsorption or exchange can affect the change in metal coordination environments. In this article, we provide a brief overview of recent progress in the effect of coordinated solvent molecules on metal coordination environments of CPs in SCSC transformations. We highlight three different categories based on their stimuli conditions, heat treatment, immersion in solvent or mother liquid, and exposure to vapor. We try to discuss the criteria for CPs in which the metal coordination spheres can be affected by the coordinated solvents, which may provide new insights into the rational design and construction of CPs with the desired structures and properties.

Herein, a new porous Zn(II)-based metal-organic framework (MOF 1) has been prepared, the structure of which featured a twofold entangled motif based on two typical secondary building units (SBUs). The gas sorption studies indicated that MOF 1 may be explored as a useful platform to encapsulate metallic nanoparticles. Then the Au@1 composite has been prepared via a facile incorporation method without extra reducing agents. The Au@1 composite has been fully characterized by HRTEM, SEM-EDX, PXRD, gas sorption, XPS, ICP, etc. Catalytic experiments showed that the Au@1 composite had a perfect catalytic performance in CO2 fixation for epoxides with different substituents under mild conditions.

A doubly interpenetrated metal–organic framework (MOF) [Zn4(L)3O]·8DMF·H2O (1, DMF = N,N-dimethylformamide) including the [Zn4O] clusters was first synthesized by employing a rigid 2,6-bis(4′-carbo...

All-inorganic CsPbX3 (X = Cl, Br, and I) nanocrystals (NCs) are emerging as attractive semiconductor materials because of their outstanding optical properties. The low resistance of CsPbX3 NCs to light, heat, oxygen, and water has been recognized as a major obstacle to their practical applications. Here, we demonstrate that the stability of CsPbX3 NC films can be dramatically enhanced by Ar plasma treatment. It is revealed that plasma irradiation can induce ligand polymerization in the NC films if the ligands contain unsaturated carbon bonds. The ligand polymerization leads to encapsulation of the NCs in the ligand polymers. Because of the precise localization of the in situ ligand polymerization under plasma irradiation and the high NC content in the films without extra additives, the polymerized area can be precisely defined down to several micrometers. This enables easy fabrication of high-resolution NC pixels for next generation displays.

In this paper, ZnO-TiO2-rGO nanocomposites were successfully synthesized by the hydrothermal method. The morphology and structure of the synthesized nanomaterials were characterized by SEM, XRD, HRTEM, and XPS. Butanone is a typical ketone product. The vapors are extremely harmful once exposed, triggering skin irritation in mild cases and affecting our breathing in severe cases. In this paper, the gas-sensing properties of TiO2, ZnO, ZnO-TiO2, and ZnO-TiO2-rGO nanomaterials to butanone vapor were studied. The optimum operating temperature of the ZnO-TiO2-rGO sensor is 145 °C, which is substantially lower than the other three sensors. The selectivity for butanone vapor is greatly improved, and the response is 5.6 times higher than that of other organic gases. The lower detection limit to butanone can reach 63 ppb. Therefore, the ZnO-TiO2-rGO sensor demonstrates excellent gas-sensing performance to butanone. Meanwhile, the gas-sensing mechanism of the ZnO-TiO2-rGO sensor to butanone vapor was also analyzed.

In this paper, gas sensing characteristics of sulfur-doped graphene oxide (S-GO) are firstly presented. The results of the sensing test revealed that, at room temperature (20 °C), S-GO has the optimal sensitivity to NH3. The S-GO gas sensor has a relatively short response and recovery time for the NH3 detection. Further, the sensing limit of ammonia at room temperature is 0.5 ppm. Theoretical models of graphene and S-doped graphene are established, and electrical properties of the graphene and S-doped graphene are calculated. The enhanced sensing performance was ascribed to the electrical properties’ improvement after the graphene was S-doped.

International audience; Alloy melts can solidify into metallic glasses if cooled fast enough to avoid crystallization. Glass-forming ability (GFA), a measure of the ease of vitrification, is vital for the fundamental understanding of glass formation, and is also crucial for the application of metallic glasses. Previous studies of GFA mainly focused on the undercooled liquid phase, while the influence of the evolution of the stable melts on GFA is rarely addressed. Here we show that the Pd42.5Ni42.5P15 glass-forming liquid, in which a first-order liquid-liquid transition (LLT) takes place at TLL = 1063 K high above its liquidus temperature, shows significantly different GFA when quenched from the temperature above or below TLL. Moreover, the pathway and kinetics of crystallization of the melt are strongly related to the kinetics of the LLT. Our work provides new insights into the vitrification process and the kinetics of crystallization, and contributes to designing more stable metallic glasses.

V-Cr-Al-O nanospheres were successfully synthesized using V2O5, Al(OH)3, CrO3, and H2C2O42O as the starting materials by a facile one-pot hydrothermal approach. Several techniques containing X-ray powder diffraction, hydrogen temperature programmed reduction, scanning electron microscopy were used to characterize the composition, morphology and redox property of V-Cr-Al-O nanospheres. The catalytic behavior of prepared nanospheres on the thermal decomposition of AP was investigated by the thermogravimetric analysis and differential thermal analysis (TG/DTA). The experimental results show that the thermal decomposition temperature of AP in the presence of V-Cr-Al-O nanospheres is to 395 °C (decreased by 35 °C), which proves better catalyst for the thermal decomposition of AP.

A new porous metal-organic framework, namely [Co3(L)(OH)2(H2O)4]·NMP·3H2O (1), has been yielded by using Co(II) and rigid V-shaped 2,6-di(2′,5′-dicarboxylphenyl)pyridine (H4L). The structure analysis revealed that MOF 1 is a three-dimensional (3D) porous framework with 1D [Co3(OH)2]n ferromagnetic chains. The gas sorption measurements and the IAST analysis indicated MOF 1 has a relatively high selectivity for C2H6 and CO2 over CH4. The magnetic properties indicated that MOF 1 has the ferrimagnetic and slow magnetic relaxation behavior, giving an interesting single-chain magnet behavior with an effective energy barrier of 15.82 K.