The well-known idea of “structure determines properties” can be understood profoundly in the case of hexagonal zinc dicyanometalate. Using density functional theory (DFT) calculations, we show the uniaxial negative thermal expansion (NTE) and negative linear compressibility (NLC) properties of Zn[Au(CN)2]2. The temperature dependence of phonon frequencies within the quasi-harmonic approximation (QHA) is investigated. The abnormal phonon hardening (frequency increase on heating) is detected in the ranges of 0–225, 320–345, and 410–430 cm–1, which can be indicative of the unusual physical properties of Zn[Au(CN)2]2. Due to the significance of low-energy phonon frequencies in Zn[Au(CN)2]2, in this work, the corresponding vibrational mode of the lowest-frequency optical phonon at the zone center is analyzed. The specific topology of a springlike framework that will produce the effects of a compressed spring on heating and an extended spring under hydrostatic pressure is identified and leads to the coexistence of uniaxial-NTE and NLC behaviors in Zn[Au(CN)2]2. The distinguishing phonon group velocity along the a axis and c axis facilitates different responses for both the axes under temperature and hydrostatic pressure field. Through an analysis and visualization of the spatial dependence of elastic tensors, it is found that a negative Poisson’s ratio (NPR) is presented in all projection planes due to the specific topology.

•A novel Mo/ZrSiN/ZrSiON/SiO2 coating was simulated and prepared.•Absorptance of 0.94 and emittance (500 °C) of 0.12 were obtained.•The coating is thermally stable up to 500 °C for 500 h in vacuum.A novel Mo/ZrSiN/ZrSiON/SiO2 solar selective absorbing coating has been investigated, which was prepared by magnetron sputtering on stainless steel substrate. A high solar absorptance of 0.94 and a low thermal emittance of 0.06 at 25 °C were achieved. By proportionally decreasing the thicknesses of the ZrSiN, ZrSiON and SiO2 layers, the thermal emittance at 500 °C was decreased significantly from 0.19 to 0.12 (Δε=0.07) while keeping the solar absorptance unchanged. The coating also showed high thermal stability at 500 °C in vacuum, implying that it is a promising candidate for high temperature concentrated solar power (CSP) applications.

•The coating is aged (in air and vacuum) to evaluate its thermal stability.•The coating shows thermal stability at 500 °C in vacuum.•The coating exhibits thermal stability after aging in air at 450 °C for 200 h.•Variation in surface morphology affects its spectral selectivity directly.•The coating exhibits enough thermal stability for potential applications in parabolic trough concentrated solar power.The thermal stability of the Al/NbMoN/NbMoON/SiO2 solar selective absorbing coatings is investigated to determine its potential applications in concentrated solar power (CSP). The coatings are deposited on stainless steel (SS) substrate by using magnetron reactive sputtering method, which exhibit high solar absorptance (αs = 0.948) and low thermal emittance (ε = 0.11, at 400 °C). The coatings are aged (in vacuum and air) at different temperatures and time durations. The aging effect is characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and Vis.-IR spectroscopy. There is no significant change in surface morphology and spectral selectivity (performance criterion (PC) value is 0.021) of the coating after aging at 500 °C for 240 h in vacuum. The coatings also keep high spectral selectivity (PC = 0.034) after aging at 450 °C for 200 h in air. Unfortunately, the value of PC increases to 0.161 when the coating is aged at the temperature of 500 °C for 200 h in air, which is attributed to diffusion and oxidation in the absorbing layers and degradation of the dense surface morphology and structure, as evidenced by XRD and SEM analysis. These results indicate that the Al/NbMoN/NbMoON/SiO2 coatings is stable up to 500 °C in vacuum and below 450 °C in air, which means enough thermal stability for potential applications in parabolic trough CSP.Download high-res image (344KB)Download full-size image

Density functional theory (DFT) calculations are used to investigate the correlation between the uniaxial negative thermal expansion (NTE) and negative linear compressibility (NLC) behaviors in Ag3[Co(CN)6]. First, we reproduce the uniaxial-NTE and NLC behaviors under temperature- and pressure-field. And then the temperature dependence of elasticity is studied. The abnormal nature of elastic constants C33 and C11+C12 as the function of temperature is predicted. The hardening of phonon modes (below 568.7 cm–1) with increasing temperature can be as an indicative for abnormal physical properties of Ag3[Co(CN)6]. Through analyzing the vibration mode with the strongest phonon hardening, the deformation of wine-rack motif in anisotropic framework can be identified as the mechanism that leads to the coexistence of uniaxial-NTE and NLC in Ag3[Co(CN)6]. The response of phonon group velocity along c-axis is intense and quicker than that of a-axis on heating and on compression, facilitating c-axis itself to be the carrier of abnormal uniaxial-NTE and NLC properties.

•The related thermodynamic properties and NTE behavior of MOF-5 are investigated by first principles.•Contrary to other inorganic NTE materials, bulk modulus of MOF-5 increases on heating.•The low-frequency phonons are closely associated with the NTE of MOF-5.•The NTE-contributing vibrational modes are elucidated clearly.The thermodynamic properties and negative thermal expansion (NTE) behavior of metal-organic framework MOF-5 are investigated within the quasi-harmonic approximation, by using density functional theory. For nanoporous MOF-5, the temperature dependence of bulk modulus increases with increasing temperature, indicating that the resistance to compression is enhanced gradually. The large NTE behavior is obtained, which agrees reasonably with the experimental data. From the Grüneisen parameter as a function of temperature, it can be found that low-frequency phonons are closely associated with the NTE of MOF-5. The corresponding vibrational modes can be viewed as the results of local deformations (translation, rotation, twisting) of BDC (1,4-benzenedicarboxylate) linker and zinc clusters. The lowest-frequency phonon mode (the transverse motion of carboxylate groups and benzene ring, zinc clusters being as rigid units) is confirmed to be most responsible for thermal contraction.

•A saturated Mo thickness of 50 nm is found to result in the lowest emittance.•We found Mo film emittance was decreased by decreasing substrate surface roughness.•Emittance of optimal Mo film is 0.05 from 25 °C to 400 °C.The thermal emittance of the Mo film, as an IR-reflector in solar selective absorbing coatings, is the most important property. The effects of the substrate material, the substrate surface roughness, the film thickness and the temperature on the thermal emittance of the Mo/substrate have been investigated. A series of Mo films with increasing film thickness were deposited on two types of substrate materials (glass and stainless steel). A saturated Mo thickness of 50 nm is found to produce the lowest thermal emittance. The thermal emittance of the Mo film is reduced by decreasing the substrate surface roughness. The emittance of the optimal Mo film remains 0.05 from 25 °C to 400 °C, which can meet the optical requirements for the IR-reflector.

The antiperovskite Mn3+xNi1–xN compounds have been synthesized and characterized by a variety of experimental techniques. After Mn doping at the Ni site, both ferromagnetic characteristics and an Invar-like effect were observed in the antiferromagnetic host material. The observed Invar-like behavior was assumed to be related to the characteristic magnetic structure induced by the doping. Neutron diffraction results prove that the Mn doping stabilizes the special Γ5g antiferromagnetic phase with strong spin–lattice coupling that can be tuned to achieve Invar-like behavior. The magnetovolume effect (MVE) and significant correlation between spin and lattice were confirmed for the Γ5g magnetic phase by the first-principles calculations. Moreover, Mn 3d electrons were revealed to be the key factor for the MVE from the calculations. Our study presents a new mechanism for precisely controlling the zero thermal expansion of a single compound by achieving the special Γ5g magnetic phase of Mn atoms.

•The Al/NbMoN/NbMoON/SiO2 coating is optimized by using optical simulation.•The optical constants are calculated with suitable dielectric function models.•The optimized coating has high absorptance and low emittance at 80 °C.•The coating exhibits excellent thermal stability at 400 °C in vacuum.•It offers a good method to quickly reach the ideal spectral selectivity.For the applications in solar thermal power, the preparation and optimization of an Al/NbMoN/NbMoON/SiO2 multilayer solar selective absorbing coating are carried out by combining experiments with optical simulation. A series of NbMoN and NbMoON single layers are deposited by magnetron reactive sputtering method with different N2/O2 gas flowing rates. And then their optical constants are obtained by fitting their reflection (R) and transmission (T) spectra in the wavelength range of 300–2500 nm using SCOUT software. These optical constants are used to design the Al/NbMoN/NbMoON/SiO2 solar selective absorbing coating so as to get the ideal spectral selectivity, i.e. high α/ε ratio. According to the optical design of the coating structure, we prepared the all-layer coating, and the thickness of each layer was optimized until the best spectral selective properties are obtained. The experimental reflectance spectrum fits very well with the simulated result. The optimized solar absorbing coating deposited on stainless steel substrate exhibited high absorptance (α=0.948) and low emittance (ε=0.050) at 80 °C. It offers a good method to quickly reach the ideal spectral selectivity through optical simulation. The thermal stability of the coating is evaluated, and it exhibits a good thermal stability in vacuum at 400 °C.

•The work focuses on improving thermal stability of Al/NbTiN/NbTiON/SiO2 coating.•Si increases the onset oxidation temperature of NbTiSiN and NbTiSiON layer.•Si additions improve the oxidation resistance of the coating at 500 °C in air.•The improved coating is stable up to 550 °C in vacuum for 100 h.In this work, the NbTiSiN and NbTiSiON layers are used instead of NbTiN and NbTiON layers to further improve the thermal stability of Al/NbTiN/NbTiON/SiO2 multilayer solar selective absorbing coating. The thermal stability of Si-doped individual layers and multilayer coatings are investigated. The X-ray diffraction (XRD) results show that Si incorporation into NbTiN (NbTiSiN) layer does not change its preferred orientation, and the Si-doped NbTiON (NbTiSiON) layer remains in amorphous phase. On the other hand, by introducing Si into NbTiN and NbTiON layers induce significant improvement of the oxidation resistance at 500 °C in air. After ageing in air at 500 °C for 2 h, the absorptance and emittance (at 400 °C) of Al/NbTiN/NbTiON/SiO2 and Al/NbTiSiN/NbTiSiON/SiO2 multilayer coatings change from 0.934/0.13 and 0.931/0.12 to 0.538/0.14 and 0.922/0.13, respectively. Meanwhile the surface roughness increases from 18.3 and 7.9 to 41.5 and 14.7 respectively, as atomic force microscopy (AFM) shows. The Al/NbTiSiN/NbTiSiON/SiO2 coating still has a high absorptance (0.910) and low emittance (0.13, at 400 °C) after ageing at 550 °C in vacuum for 100 h. It displays that Si-doping play an important role in the improvement of the thermal stability.

Here, we report a simple, sensitive and selective colorimetric method for detection of dopamine (DA) using gold nanoparticles (AuNPs). AuNPs of 15 nm size were synthesized by the citrate reduction method. The method is based on the principle that the aggregated AuNPs induced by melamine can be separated by the melamine–DA conjugate through hydrogen-bonding interactions, and thus, the blue color of AuNPs changes to blue-purple. Under optimized conditions, melamine–AuNPs are highly specific for DA and can detect melamine down to a concentration of 33 nM. Furthermore, we demonstrate the application of the approach in human urine samples, which suggests its great potential for diagnostic purposes.

•BiOCl/Bi2MoO6 composite has been prepared by a one-step hydrothermal synthesis method.•The photocatalytic activity of BiOCl/Bi2MoO6 composite photocatalyst is better than the single BiOCl or the single Bi2MoO6.•The special band structure of the composite leads to superior photocatalytic property.BiOCl/Bi2MoO6 composite was prepared using a one-step hydrothermal synthesis method at 160 °C. The as-synthesized sample was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV–vis. diffuse reflectance spectra (DRS). The photocatalytic activity of the product was evaluated through photocatalytic degradation of methyl orange (MO) and phenol under visible light irradiation. The results show that the BiOCl/Bi2MoO6 composite photocatalyst possesses better photocatalytic activity in degrading MO and phenol than the single BiOCl or the single Bi2MoO6. The better photocatalytic properties may be due to the special band structure of the composite, because of which electrons and holes are separated effectively.

•Two distinct magnetic transitions at TN and lower temperature affected by doping were discussed.•The broadened negative thermal expansion behavior was observed in Mn3AgxMnyN.•All compounds show nearly zero temperature coefficient of resistivity behavior.•Tunable values of temperature coefficient of resistivity were obtained.The antiperovskite compounds Mn3AgxMnyN with Ag vacancies and Mn doping at Ag site were synthesized and investigated. The introduction of Ag vacancies has a very small influence on magnetic transitions. However, the magnetic transitions at TN (Néel temperature) and Tt (transition at lower temperature) gradually overlap with Mn doping accompanied by broadening of negative thermal expansion behavior. We also observed the nearly zero temperature coefficient of resistivity (NZ-TCR) behavior above magnetic order–disorder transition. The tunable TCR values from positive to negative could be achieved in Mn3AgxMnyN by reducing the contribution of (electron–phonon) e–p scattering in resistivity. Our results reveal the significance of e–p scattering for the evolution of TCR values, which could enrich the understanding of NZ-TCR behavior in antiperovskite manganese nitrides.

One of the specific subjects in frustrated magnetic systems is the phenomenon coupled with noncollinear magnetism, such as zero or negative thermal expansion (ZTE or NTE) in antiperovskite compounds. The first-principles calculations and neutron powder diffraction (NPD) are used to reveal the control of the noncollinear Γ5g antiferromagnetic (AFM) structure and corresponding thermal expansion properties in Mn3Zn0.875X0.125N (X = Mn, Ge, and Sn). Based on the optimal exchange-correlation functional, our results demonstrate that X (X = Mn, Ge, and Sn) doping at Zn site could stabilize the noncollinear Γ5g AFM structure and produce magnetovolume effect (MVE). The predictions of Γ5g AFM ground state and MVE is further verified by the NPD results of Mn3Zn0.83Mn0.15N0.99. Intriguingly, this special magnetic structure with strong spin–lattice coupling can be tunable to achieve ZTE behavior. On the basis of these results we suggest that frustrated magnetic systems with noncollinear Γ5g AFM structure of Mn atoms in Mn3ZnN series of compounds are favorable candidates for a new class of ZTE material.

The crystal and magnetic structures of antiperovskite compounds Mn3SnC, Mn3Sn0.95C0.9, and Mn3Sn0.93Si0.07C0.94 were studied as a function of temperature and magnetic field by neutron powder diffraction. For Mn3SnC, the magnetic field induces a dramatic variation of antiferromagnetic moment and lattice parameter. Because of this spin–lattice coupling, the “square” antiferromagnetic (AFM) structure plays a key role in inducing a negative thermal expansion in the material. Moreover, the thermal expansion parameter is closely related to the rate of change of the AFM moment, which can be controlled by introducing vacancies or by doping. The variations of the AFM moment and lattice parameter in Mn3SnC with magnetic field make it possible to use the tunable properties for technical applications.

•A new solar selective absorbing coating of SS–(Fe3O4)/Mo/TiZrN/TiZrON/SiON was prepared on SS substrate.•The new coating exhibits a high absorptance of 0.95 and a low emittance of 0.08.•The spectral properties of the coating are stable up to 500 °C in vacuum.In this study, a solar spectral selective absorbing coating of SS–(Fe3O4)/Mo/TiZrN/TiZrON/SiON exhibiting an absorptance of 0.95 and an emittance of 0.08 at 80 °C is reported. The structure and morphology of each layer were investigated by X-ray and Fourier transform infrared spectroscopic analyses. After heat treatment at 500 °C for 300 h in vacuum, the values of absorptance and emittance became 0.92 and 0.10 (at 80 °C), respectively. Moreover root mean square roughness of the coating measured by atomic force microscopy increased to 8.14 nm from 4.79 nm, indicating good thermal stability at 500 °C.

An Mn3Cu0.5Ge0.5N/Cu composite was synthesized with 50 wt.% Cu and 50 wt.% Mn3Cu0.5Ge0.5N. The composite has a nearly zero thermal expansion behavior around room temperature and consists of Cu, Mn3Cu0.5Ge0.5N with a small number of MnO particles. There are no chemical reactions between these phases and the thermal expansion property of the composite is stable. Based on the distribution of Cu and Mn3Cu0.5Ge0.5N phases in the composite, we built a structure model to clarify the stability of Mn3Cu0.5Ge0.5N/Cu composite.

•A simple hydrothermal technique combined with a special ion-exchange route has been developed for the synthesis of AgCl/BiOCl composite nanostructure.•The photocatalytic activity is improved greatly by composited AgCl nanaoparticles, compared with pure black BiOCl microsphere.•The effective interfacial charge transfer enables the AgCl/BiOCl composite to exhibit superior photocatalytic property.In this paper, AgCl/BiOCl composite nanostructure has been synthesized by a facile ion exchange route between black BiOCl microsphere and AgNO3 solution. The as-obtain products are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and X-ray photoelectron spectroscopy (XPS). Photodegradation experiments show that the photocatalytic activity of AgCl/BiOCl composite nanostructure is improved greatly by composited AgCl nanoparticles, compared with pure black BiOCl microsphere. The excellent photocatalytic activity of AgCl/BiOCl composite nanostructure with special surface morphology may be attributed to decreasing recombination of the photo-excited electron–hole pairs. In addition, AgCl/BiOCl composite possesses strong absorption to visible light which can also improve the photocatalytic efficiency.

Black nanostructured BiOCl microspheres were directly synthesized by a hydrothermal method. The black ball-like BiOCl microspheres and black flower-like BiOCl microspheres were obtained using different surfactant. The color of the BiOCl microspheres turned from black to white when being annealed at 400 °C in air for 3 h and could be recovered to black by exposure to ultraviolet light for a few hours. The photocatalytic activity of both the black and the white BiOCl microspheres was characterized by the photo-degradation of methyl orange dye under visible light irradiation. The black ball-like nanostructure BiOCl displayed the best photocatalytic activity, compared with the white BiOCl and the black flower-like BiOCl. It can degrade the methyl orange dye to 20% within 70 min under visible light irradiation. The high activity of the BiOCl ball-like sphere may own to its special morphology, strong absorption in visible light range and the existence of oxygen vacancies.

The antiperovskite Mn3ZnN is studied by neutron diffraction at temperatures between 50 and 295 K. Mn3ZnN crystallizes to form a cubic structure at room temperature (C1 phase). Upon cooling, another cubic structure (C2 phase) appears at around 177 K. Interestingly, the C2 phase disappears below 140 K. The maximum mass concentration of the C2 phase is approximately 85% (at 160 K). The coexistence of C1 and C2 phase in the temperature interval of 140–177 K implies that phase separation occurs. Although the C1 and C2 phases share their composition and lattice symmetry, the C2 phase has a slightly larger lattice parameter (Δa ≈ 0.53%) and a different magnetic structure. The C2 phase is further investigated by neutron diffraction under high-pressure conditions (up to 270 MPa). The results show that the unusual appearance and disappearance of the C2 phase is accompanied by magnetic ordering. Mn3ZnN is thus a valuable subject for study of the magneto-lattice effect and phase separation behavior because this is rarely observed in nonoxide materials.

The Ni-doping effect on the lattice and magnetic properties in Mn3Zn1−xNixN was first reported. The ground-state magnetic structure for Mn3ZnN is noncollinear antiferromagnetic Γ5gΓ5g. The introduction of Ni-doping induces a continuous spin rotation in the (111) plane from Γ5gΓ5g to weak ferromagnetic Γ4gΓ4g configurations, exhibiting a change from antiferromagnetic to weak ferromagnetic with increasing Ni content. In particular, when Ni content increased to x≥0.5x≥0.5, Mn3Zn1−xNixN shows an abrupt lattice contraction near the magnetic transition with increasing temperature. The normal–abnormal lattice variation in Mn3Zn1−xNixN is explained by the competition between the negative free energy variation δFeδFe and the positive δF0δF0.Highlights► We investigated Ni-doping effect on the lattice and magnetic properties of Mn3ZnN. ► We note that the AFM phase is replaced by the weak ferromagnetic phase with increasing Ni content. ► The evolution of magnetic structure with Ni-doping content is attributed to spin rotation. ► The lattice contraction originates from the large negative electronic contribution δFeδFe.

The TiO2/Ag/Ti/TiO2/SiON multilayer film was deposited on glass substrate at room temperature using magnetron sputtering method. By varying the thickness of each layer, the optical property was optimized to achieve good selective spectral filtering performance in Vis–NIR region. The multilayer film achieves maximum transmittance of 92.7% at 690 nm, in which the both TiO2 layers are 33 nm. For good conductivity and transmittance, a 4 nm Ti layer and a 30 nm SiON layer are necessary.Highlights► We prepared and investigated TiO2/Ag/Ti/TiO2/SiON multilayer film. ► The film exhibits good optical and electrical properties. ► The thicknesses of each layer of the films were optimized. ► The SiON layer was deposited as a cover due to chemical stability and anti-diffusion.

The synthesis of lotus-root-like NiO nanosheets and flower-like NiO microspheres was realized through a simple hydrothermal method and subsequent calcination. The diameter of the lotus-root-like NiO nanosheets is about 400 nm and the pore size is about 5∼20 nm. The diameter of the flower-like NiO microspheres is about 2.5 μm, and are composed of staggered lotus-root-like nanosheets. During the synthetic procedure, aqueous ammonia was used as an alkaline complexing reagent, and PVP was used as the template. Interestingly, when the pH value of the precursor solution increased from 8.30 to 10.80, the NiO nanosheets gradually assembled into microspheres, indicating that aqueous ammonia plays a key role in controlling the final morphology. Based on the experimental observation and analysis, a possible mechanism is proposed to understand the formation of the NiO nanostructured materials. In addition, the resultant NiO nanostructures present anomalous magnetic properties and display a spin-glass state at low temperature.

ZnO nanorod arrays were fabricated on Cu2O thin film by a simple low-temperature liquid-phase-deposition method. The samples were characterized by X-ray powder diffraction (XRD) and field emission scanning electron microscopy (FESEM). The UV-Vis spectroscopy showed that the obtained sample was able to absorb a large part of visible light (up to 650 nm). Their photocatalytic activities were investigated by degradation of dye methylene blue (MB) under UV-Vis and visible light irradiation. It was found that the photocatalytic activity of the ZnO/Cu2O NRs was higher than the ZnO/ZnO NRs under UV-Vis light. In a word, Cu2O played an important role in enhancing the photocatalytic activity of the ZnO/Cu2O NRs.

The antiperovskite structure Mn3Cu(Ge)N thin films were grown on single crystal Si (100) substrates by facing target magnetron sputtering. It is found that the films exhibit (100) preferred orientation. Ge-doping does not change the antiperovskite structure but leads to obvious changes in surface morphologies, magnetic and electronic transport properties. As a function of temperature, the resistivity of the films shows a semiconductor-type behavior. Moreover, it is worth noting that an abrupt change of resistivity is observed and magnetic ordering of the films changes from ferrimagnetic (FI) to antiferromagnetic (AFM) due to Ge-doping. In addition, both the transition temperature (Tt) and Néel temperature (TN) move towards higher temperature with increasing Ge content.

The magnetic and electronic transport properties of the antiperovskite Mn3NiN thin film deposited on quartz substrate using magnetron sputtering were investigated. The film shows a (100) preferred orientation. It is worthwhile noting that a positive magnetoresistance (MR) effect was found in the whole measured temperature region and the maximum MR value by 31% was obtained at about 300 K under 2 T. On the other hand, when cooling from room temperature, a spin-glass behavior was also observed in the Mn3NiN film and the Tb shifted to lower temperature with increasing external magnetic field. In contrast to the bulk counterpart, the temperature dependent resistivity of the film shows a semiconductor-like behavior.Highlights► The Mn3NiN film was prepared on quartz substrate for the first time. ► A magnetoresistance effect appearing in a wide temperature range was observed. ► The maximum MR value by 31% was obtained at about 300 K. ► A spin-glass behavior was observed at low temperature. ► The resistivity of the film shows a semiconductor-like behavior.

Bismuth oxycholoride (BiOCl) nano/microstructures, including flake and nanowire arrays, were successfully synthesized on Anodic Aluminum Oxide (AAO) templates via sol–gel combined with the vacuum air-extraction method. The flakes are almost vertically aligned on the surface, but nanowires at a lower sol concentration are aligned along the channels. A possible formation mechanism is proposed. Furthermore, the photocatalytic activity of the BiOCl nano/microstructures is investigated by photocatalytic decomposition of Rhodamine B (Rh B) dye under UV–Visible light irradiation. Compared with the BiOCl flake-like film on the glass substrate, where the flakes are horizontally oriented on the surface, the vertically aligned flake and nanowire arrays on AAO templates, have higher photocatalytic efficiency.

The magnetization and electrical resistivity of Mn3−xFexSnC (0.5≤x≤1.3) were measured to investigate the behavior of the complicated magnetic phase transitions and electronic transport properties from 5 to 300 K. The results obtained demonstrate that Fe doping at the Mn sites of Mn3SnC induces a more complicated magnetic phase transition than that in its parent phase Mn3SnC from a paramagnetic (PM) state to a ferrimagnetic (FI) state consisting of antiferromagnetic (AFM) and ferromagnetic (FM) components, while, with the change of Fe-doped content and magnetic field, there is a competition between the AFM component and FM component in the FI state. Both the Curie temperature (TC)(TC) and the saturated magnetization MsMs increase with increasing xx. The FM component region becomes broader with further increasing Fe-doped content xx. The external magnetic field easily creates a saturated FM state (and increased TCTC) when H≥1500Oe. Fe doping quenches the negative thermal expansion (NTE) behavior from 200 to 250 K reported in Mn3SnC.Research highlights► Fe doping at Mn sites induces a more complicated magnetic phase transition. ► There is a competition between the AFM component and the FM component in the FI state. ► The Curie temperature TCTC and the saturated magnetization MsMs increase with increasing xx. ► The external magnetic easily creates a saturated FM state and increased TCTC. ► Fe doping quenches the negative thermal expansion behavior reported in Mn3SnC.

Bismuth oxychloride (BiOCl) nanowire arrays have been successfully prepared employing the Anodic Aluminum Oxide (AAO) template assisted sol–gel method. Nanowires of 100 nm diameter and length 2–6 μm, assembled in the porous of AAO templates, were formed. XRD and HRTEM results show that the nanowires are pure BiOCl polycrystal phase without Bi2O3 or BiCl3. The photocatalytic activity of BiOCl nanowire arrays was investigated by the degradation of Rhodamine B dye solution under UV irradiation.

The temperature-dependent magnetization, lattice, and transport properties of Mn3Sn1−xGexC (0≤x≤0.50≤x≤0.5) compounds are systematically investigated. The Mn–Mn atomic distance decreases as Ge content is increased, and the transition temperature from ferromagnetic (or ferrimagnetic) to paramagnetic state decreases too. Mn3SnC has a large magnetovolume effect (MVE). However, Ge-doping in Mn3SnC gradually reduces the MVE, till the MVE disappears. Whether there is an abnormal lattice change or not, there always exists an anomalous increase in resistivity near the magnetic phase transition point with decreasing temperature.

•We first proposed to use a AlNi alloy to fabricated cermet absorption coating.•We obtained an excellent optical property AlNi–Al2O3 absorbing coating.•Preliminary thermal stability tests show AlNi–Al2O3 coating is promising for CSP.A new solar selective absorbing coating of AlNi–Al2O3 cermet multilayer is designed and prepared on Cu or stainless steel (SS) substrate by magnetron sputtering. The coating consists of an IR-reflective metallic layer, an absorption bilayer and an anti-reflection layer from substrate to top. The IR-reflective metallic layer is Cu or Mo. The absorption bilayer consists of a high metal volume fraction (HMVF) AlNi–Al2O3 cermet sublayer and a low metal volume fraction (LMVF) AlNi–Al2O3 cermet sublayer. The anti-reflection layer is Al2O3. The optical performance (α/ε) of the coating is 0.94/0.07 on Cu substrate and 0.95/0.078 on SS substrate by optimizing the metal volume fraction and thickness of each layer. The samples deposited on SS substrate were heated at 500 °C for 138 h and 284 h in vacuum to evaluate the optical stability. Experimental results showed that the high temperature stable AlNi intermetallic compound, instead of Mo in the traditional Mo–Al2O3 coatings, displayed a good thermal stability at 500 °C. There is no significant change appearing in the optical properties of the coating after the heat treatment. It means that the new coating is a good potential candidate as a high temperature solar selective absorbing coating for parabolic trough concentrated solar power (CSP).

The temperature-dependent magnetization, lattice, and transport properties of Mn3Sn1−xGexC (0≤x≤0.5) compounds are systematically investigated. The Mn–Mn atomic distance decreases as Ge content is increased, and the transition temperature from ferromagnetic (or ferrimagnetic) to paramagnetic state decreases too. Mn3SnC has a large magnetovolume effect (MVE). However, Ge-doping in Mn3SnC gradually reduces the MVE, till the MVE disappears. Whether there is an abnormal lattice change or not, there always exists an anomalous increase in resistivity near the magnetic phase transition point with decreasing temperature.

•The Al/NbMoN/NbMoON/SiO2 coating is optimized by using optical simulation.•The optical constants are calculated with suitable dielectric function models.•The optimized coating has high absorptance and low emittance at 80 °C.•The coating exhibits excellent thermal stability at 400 °C in vacuum.•It offers a good method to quickly reach the ideal spectral selectivity.For the applications in solar thermal power, the preparation and optimization of an Al/NbMoN/NbMoON/SiO2 multilayer solar selective absorbing coating are carried out by combining experiments with optical simulation. A series of NbMoN and NbMoON single layers are deposited by magnetron reactive sputtering method with different N2/O2 gas flowing rates. And then their optical constants are obtained by fitting their reflection (R) and transmission (T) spectra in the wavelength range of 300–2500 nm using SCOUT software. These optical constants are used to design the Al/NbMoN/NbMoON/SiO2 solar selective absorbing coating so as to get the ideal spectral selectivity, i.e. high α/ε ratio. According to the optical design of the coating structure, we prepared the all-layer coating, and the thickness of each layer was optimized until the best spectral selective properties are obtained. The experimental reflectance spectrum fits very well with the simulated result. The optimized solar absorbing coating deposited on stainless steel substrate exhibited high absorptance (α=0.948) and low emittance (ε=0.050) at 80 °C. It offers a good method to quickly reach the ideal spectral selectivity through optical simulation. The thermal stability of the coating is evaluated, and it exhibits a good thermal stability in vacuum at 400 °C.

The magnetization and electrical resistivity of Mn3−xFexSnC (0.5≤x≤1.3) were measured to investigate the behavior of the complicated magnetic phase transitions and electronic transport properties from 5 to 300 K. The results obtained demonstrate that Fe doping at the Mn sites of Mn3SnC induces a more complicated magnetic phase transition than that in its parent phase Mn3SnC from a paramagnetic (PM) state to a ferrimagnetic (FI) state consisting of antiferromagnetic (AFM) and ferromagnetic (FM) components, while, with the change of Fe-doped content and magnetic field, there is a competition between the AFM component and FM component in the FI state. Both the Curie temperature (TC) and the saturated magnetization Ms increase with increasing x. The FM component region becomes broader with further increasing Fe-doped content x. The external magnetic field easily creates a saturated FM state (and increased TC) when H≥1500Oe. Fe doping quenches the negative thermal expansion (NTE) behavior from 200 to 250 K reported in Mn3SnC.Research highlights► Fe doping at Mn sites induces a more complicated magnetic phase transition. ► There is a competition between the AFM component and the FM component in the FI state. ► The Curie temperature TC and the saturated magnetization Ms increase with increasing x. ► The external magnetic easily creates a saturated FM state and increased TC. ► Fe doping quenches the negative thermal expansion behavior reported in Mn3SnC.

•Reflectance transition position is determined by HMVF layer.•R transition position is blue-shifted by reducing f or thickness of HMVF layer.•It provides easy ways to obtain low emittance at elevated temperature.The reflectance spectra of the Al/double cermet Al-AlN/AlOxNy solar selective absorbing coating are simulated. Two methods have been found to effectively tune the position of reflectance transition of the Al-AlN cermet solar selective absorbing coating, which is crucial to obtain a low emittance at elevated temperature. The position of reflectance transition is mainly determined by the high metal volume fraction (HMVF) cermet layer. It is effectively tuned to shift to lower wavelength by reducing the metal volume fraction or the thickness of the HMVF layer. This provides easy ways to tune the position of reflectance transition.

In recent years, finding photocatalysts that can operate at a broad range of wavelengths is interesting in photocatalytic research field. In this study, CsxWO3/BiOCl composites with different mass ratios of CsxWO3 were synthesized by solid state calcination method. The as-prepared samples were characterized by X-ray diffraction analysis, scanning electron microscopy, photoluminescence emission spectroscopy, photocurrent and UV–vis. diffuse reflectance spectra. The photocatalytic activity of the products was evaluated through photocatalytic degradation of rhodamine B (RhB) and methylene blue (MB) under visible light irradiation. The results show that the photocatalytic activity of the CsxWO3/BiOCl composite photocatalyst with the mass ratio 1/3 is better than the single CsxWO3 and BiOCl. The significantly improved photocatalytic activity is attributed to the synergetic effect of two semiconductors, such as the extended visible absorption and the promoted electron–hole pairs separation. The novel composite photocatalyst will have a great application potential in the field of environmental purification.BiOCl with a wide band gap energy only harvests the UV light. It performs good photocatalytic activity under visible light irradiation due to its unique and outstanding physical and chemical properties. The band gap energy of CsxWO3 is around 2.5 eV, which exhibits a strong absorption in wide range of 200–2500 nm. We find that CsxWO3/BiOCl composite with a mass ratio 1/3 has a better photocatalytic activity than the single BiOCl and CsxWO3 by degrading RhB and MB under the visible light irradiation. It attributes that coupling narrow band gap CsxWO3 with wide band gap BiOCl semiconductor could lead to an efficient electron–hole pairs separation.Figure optionsDownload full-size imageDownload as PowerPoint slide