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Abstract Experimental measurement of surface energy is rather difficult at finite temperature. This work develops a first-principles method to estimate the effects of finite temperature on the surface energy of Al alloys. The surface energies of four planes, namely, (100), (110), (111) and (112) planes, have been calculated as a function of the finite temperature, as well as the interaction energies between the solute atoms and these surfaces. The uniform distribution (UFD) model is used to treat the distributions of solute atoms in investigating the microcrack nucleation mechanism. The results suggest that the four surface energies of pure Al decrease slightly with increasing the temperature. While Sn atom can drastically reduce the four surface energies of Al alloys at relatively high solute concentration, which obviously increases the probability of forming a new surface, inducing more microcracks in Al alloys. Interestingly, Cu atom can inhibit the microcrack nucleation of (100) and (111) surfaces by slightly increasing their surface energies. Microcracks in Al alloys prefer to nucleate along the (111) surface due to the lower surface energy. This work provides a valuable insight for further exploring the surface characteristics of Al alloys at finite temperature. Highlights • Effects of finite temperature on the surface energy of Al alloys are investigated by first-principles calculations. • Results indicate that finite temperature has a small impact on the surface energy. • Sn atom can obviously increase the probability of the microcrack nucleation. • Cu atom can inhibit the microcrack nucleation of (100) and (111) surfaces. [ABSTRACT FROM AUTHOR]

Abstract In this study, the NiO additive was employed as a sintering aid to prepare dense BaZr 0.9 Y 0.1 O 3-δ (BZY10) ceramics for proton ceramic fuel cell (PCFC) and electrolysis cell (PCEC) applications. It was found that the NiO additive contributed to facilitating the grain growth and enhancing the proton conductivity of BZY10 ceramics. However, the subsequent studies on the transport number reveal a detrimental effect of NiO additive on increasing the electronic leakage of BZY10 ceramics under humid oxidizing atmosphere. This is expected to cause the misdiagnosis of the electrocatalytic activity of PCFC cathodes and a lower Faraday efficiency of PCECs. Considering the utilization of BZY10 ceramics as the proton conducting electrolyte, it is preferred to obtain a high density (∼95%) and applicable proton conductivity at the minimum NiO usage. This strategy was achieved by sintering the nanocrystalline BZY10 powders with 0.2 wt% NiO additive at 1500 °C for 6 h in air, of which the usage is 80% lower than that in the well-known solid state reactive sintering approach. Highlights • 0.2 wt% NiO additive facilitates densification of BZY10 proton conducting ceramics. • Compared to BZY10 ceramic, 0.2 wt%NiO addition induces even grain size distribution. • BZY10 + 0.2 wt%NiO ceramics give a proton conductivity of 0.0024 S cm−1 at 400 °C in H 2 • 0.2 wt% NiO addition increases electronic leakage of BZY10 in oxidizing atmosphere. [ABSTRACT FROM AUTHOR]

The cross-correlation technology is applied to decrease the noise figure of microwave photonic link(MPL) for the first time in this paper. Firstly, both effects of the intensity of the laser and the bias voltage of the EOM on the noise figure of MPL are analyzed and optimized. Then, a cascaded low-noise amplifier is added in front of MPL for lower noise figure. Finally, the double laser - double detector structure based on cross-correlation technology is used to offset different kinds of uncorrelated noise in the link and experiments show that the noise figure is further reduced by 3 dB. [ABSTRACT FROM AUTHOR]

Sodium hydroxide (NaOH) and calcium hydroxide (Ca(OH) 2 ) respectively dissolved in water and 70% glycerol were applied to treat sugarcane bagasse (SCB) under the condition of 80 °C for 2 h. NaOH solutions could remove more lignin and obtain higher enzymatic hydrolysis efficiency of SCB than Ca(OH) 2 solutions. Compared with the alkali-water solutions, the enzymatic hydrolysis of SCB treated in NaOH-glycerol solution decreased, while that in Ca(OH) 2 -glycerol solution increased. The lignin in NaOH-water pretreatment liquor could be easily recovered by calcium chloride (CaCl 2 ) at room temperature, but that in Ca(OH) 2 -water pretreatment liquor couldn’t. NaOH pretreatment is more suitable for facilitating enzymatic hydrolysis and lignin recovery of SCB than Ca(OH) 2 pretreatment. [ABSTRACT FROM AUTHOR]

• Bulky and polar polyethylene glycol tails were attached to tetrathiafulvalene. • Viscous oils with infinite miscibility with electrolyte solvents were obtained. • Excellent electrochemical stability was achieved with high redox potentials. • Cross-over of active species within flow batteries was addressed by membrane design. • Excellent flow battery performance was achieved and supported by DFT calculations. Redox flow batteries (RFBs) are highly promising electrochemical systems for large-scale energy storage. To develop high energy density non-aqueous catholyte for RFBs, herein, two polar and bulky polyethylene glycol tails have been attached to the tetrathiafulvalene (TTF) core by ester exchange reactions. Such modification turns scarcely soluble TTF particles into viscous oils, which are totally miscible with the conventional organic electrolytes. The 4,4′(5′)-bis(2-(2-methoxyethoxy)ethyl)carboxylate -tetrathiafulvalene (TTF-BMEEC) with a mass-based specific capacity of 107.84 mAh g−1 is systematically evaluated in a hybrid RFB. When paired with a Li foil electrode and a permselective separator, the catholyte consisting of 1.0 M of TTF-BMEEC delivers two high discharge voltage plateaus of 3.55 and 3.88 V, a large volumetric capacity of 49.6 Ah L−1, an outstanding energy density of 178.0 Wh L−1, and a high cycling capacity retention of 91.5% after 100 cycles at the current density of 10 mA cm−2. The excellent electrochemical stability of TTF-BMEEC is confirmed by UV–vis and 1H NMR investigations and supported by density functional theory (DFT) calculations. These results demonstrate that molecular engineering has great potential for the development of high performance organic redox-active materials for RFBs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Investigation of corrosion mechanism assisted by first-principle calculation. • Correlation between interface properties and electrochemical stability. • Reinforcement on interface stability by TiC/TaC and TaC/C contacting. • A low corrosion current density of 0.28 μA cm−2 for the TaC/TiC/TaC/C coating. In this study, first-principle calculation is used to investigate the TiC (1 1 1)/TaC (1 1 1) interface in terms of surface energy, work function, adhesion energy, and electronic structure. Compared with TaC (1 1 1), the TiC (1 1 1) surface shows a higher surface energy and a lower electronic work function. The surface passivation of TiC can be achieved by covering the TaC layer. Besides, the interface bonding configuration of TiC (1 1 1)/TaC (1 1 1) that relates to corrosion resistance is studied in detail. In experimental verification, a set of TiC-based coatings are investigated by potentiodynamic polarization, potentiostatic polarization, and impedance. Compared with pure TiC and TiC/C coatings, the TaC/TiC/TaC/C structure exhibits the lowest corrosion current density of 0.28 μA cm−2 and the lowest corrosion tendency. SEM observation also reveals its minimal morphological damage after potentiostatic polarization. The modified multilayer coating presented in this work is successfully used as the protecting structure of stainless-steel bipolar plate, which may be of great significance to the light weight metallic bipolar plate in proton exchange membrane fuel cells. [ABSTRACT FROM AUTHOR]

Abstract: (Liquid+liquid) equilibrium (LLE) data for ternary system {heptane (1)+ m-xylene (2)+ N-formylmorpholine (3)} have been determined experimentally at temperatures ranging from 298.15K to 353.15K. Complete phase diagrams were obtained by determining solubility and tie-line data. Tie-line compositions were correlated by Othmer–Tobias and Bachman methods. The universal quasichemical activity coefficient (UNIQUAC) and The non-random two liquids equation (NRTL) were used to correlate the phase equilibrium in the system using the interaction parameters determined from experimental data. It is found that UNIQUAC and NRTL used for LLE could provide a good correlation. Distribution coefficients, separation factors, and selectivity were evaluated for the immiscibility region. [Copyright &y& Elsevier]

Abstract: Liquid–liquid equilibrium (LLE) data for the ternary system (methylcyclohexane–benzene–N-formylmorpholine) are reported under atmospheric pressure and at temperatures ranging from 293.15 to 333.15K. Complete phase diagrams were obtained by determining solubility and tie-line data. The tie-line data were compared with the results predicted by the UNIQUAC and the NRTL methods. Distribution coefficients, separation factors and selectivity were evaluated for the immiscibility region. [Copyright &y& Elsevier]

Organic redox-active compounds are promising alternatives to traditional inorganic counterparts because of their sustainable resources and highly tunable properties. However, their solubility in organic electrolyte solvents and the sluggish electrode reactions hinder their further development. Herein, an intrinsically microporous decabromopropyl pillar[5]arene (P5Br) was used to support the methyl viologen (MV) functionality to yield two non-crosslinked and crosslinked organic electrode materials, namely MV-P5Br and CMV-P5Br, respectively. When evaluating against Li metal counter electrode, the MV-P5Br and CMV-P5Br electrodes delivered high discharge capacities of 87.9 and 92.7 mAh g−1 at 0.1 C, respectively, which are close to their theoretical values. After galvanostatic cycling at 0.1 C for 100 cycles, the CMV-P5Br electrode maintained a discharge capacity of 82.3 mAh g−1, much higher than the 43.7 mAh g−1 of the MV-P5Br electrode. When the current rate was increased to 10 C, the CMV-P5Br electrode delivered a discharge capacity of 60.7 mAh g−1, also higher than the 41.3 mAh g−1 of the MV-P5Br electrode. The increased cycling stability and rate performance of the CMV-P5Br electrode were attributed to the diminished solubility and the enhanced ion diffusion coefficient of the active material. When the counter electrode was changed to Na metal, similar results were obtained, suggesting that the CMV-P5Br electrode can also be used in Na-ion systems. This study demonstrates that the combination of crosslinked and microporous structure is highly effective to boost the electrochemical performance of organic redox-active compounds for rechargeable batteries. [Display omitted] [ABSTRACT FROM AUTHOR]

Biomedical magnesium (Mg) alloys remain a challenge for their mainstream application, because the combination of bio‐mechanical stress and corrosive physiological environment leading to stress corrosion cracking (SCC). It is crucial to avoid the sudden brittle fracture of Mg alloys in vivo for predicting their service duration. However, the key factors, such as surface or physiological environment features, determining the origination or propagation of SCC behavior are still unclear. In the present study, a prefabricated surface defects coating was prepared by the phytic acid (PA, C6H18O24P6) conversion treatment. Four mimicking physiological media were used, ranging from simple to equivalent (Dulbecco's Modified Eagle Medium and Protein [DMEM+Pro]). The results showed that the PA film with numerous micro‐cracks provided limited protective ability in synthetic biological media. A striking finding was determined that although initial high corrosion rate of samples in DMEM+Pro led to an increased SCC nucleation, significant ductile fracture with elongation to failure (14.86%) was observed. Combined with the fracture features, the adsorption or deposition of biological composition into the tunnel of SCC cracks significantly inhibited the hydrogen embrittlement (HE) behavior. These results indicate that preventing the propagation of SCC crack by biological composition, rather than nucleation, plays a key role in avoiding the sudden fracture of Mg alloys. It provides a novel perspective to determine the non‐brittle fracture of Mg alloys for biomedical applications. Highlights: Prefabricated surface‐defective Mg novelty used to study stress corrosion crackingConfirming ductile fracture of Mg alloy in vitro organic‐containing mimic mediumInhibiting the micro‐crack propagation relied on biological composition depositionThe crack propagation than nucleation plays a key role in avoiding brittleness [ABSTRACT FROM AUTHOR]

In this study, S-doped graphitic carbon nitride (S-C3N4) was prepared using the high-temperature polymerization method, and then S-C3N4/AgCdS heterojunction photocatalyst was obtained using the chemical deposition method through loading Ag-doped CdS nanoparticles (AgCdS NPs) on the surface of S-C3N4. Experimental results show that the AgCdS NPs were evenly dispersed on the surface of S-C3N4, indicating that a good heterojunction structure was formed. Compared to S-C3N4, CdS, AgCdS and S-C3N4/CdS, the photocatalytic performance of S-C3N4/AgCdS has been significantly improved, and exhibits excellent photocatalytic degradation performance of Rhodamine B and methyl orange. The doping of Ag in collaboration with the construction of a Z-scheme heterojunction system promoted the effective separation and transport of the photogenerated carriers in S-C3N4/AgCdS, significantly accelerated its photocatalytic reaction process, and thus improved its photocatalytic performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • The spectral positions of photonic bandgaps were estimated by theoretical simulation. • The first-order photonic bandgap was verified to be located in the infrared region. • The formation of the photonic bandgaps appreciably improved the overall properties. • A small amount of CuAl 2 O 4 was produced by controlling electrodeposition voltage. • The CuAl 2 O 4 formation enhanced the thermal stability of the coating properties. Solar selective absorption coatings based on anodic aluminum oxides (AAO) were prepared via an anodization technique and a subsequent alternating current electrodeposition of Cu-Ni nanoparticles at the bottom. The phase structure, microstructure and solar selective absorption properties of the AAO coatings were investigated with respect to their preparation conditions. Moreover, the dependence of the solar selective absorption properties on thermal annealing history was examined. One-dimensional AAO photonic crystal coatings were produced by anodization under period pulse voltages. The spectral positions of photonic bandgaps were estimated for the AAO photonic crystal coatings. The first-order photonic bandgap was verified to be located in the infrared region. The construction of the photonic crystal structure appreciably lowered the infrared emittance and as a result improved the overall properties of the AAO photonic crystal coatings. A small amount of CuAl 2 O 4 was formed in the electrodeposition layer of AAO photonic crystal coatings by controlling the amplitude of applied electrodeposition voltage at 14 V. The formation of the CuAl 2 O 4 minimized the oxidization of the Cu-Ni nanoparticles at elevated temperatures and thereby enhanced the thermal stability of the solar selective absorption properties. The AAO photonic crystal coating prepared under the electrodeposition voltage showed a solar absorptance of 0.90, an infrared emittance of 0.11 and a spectral selectivity of 8.12 at room temperature, while retaining a spectral selectivity of 6.47 after being annealed at 300 °C for 24 h. [ABSTRACT FROM AUTHOR]

In this short communication, TiO2-nanoparticle-functionalized biodegradable polylactide (PLA) nonwoven scaffolds with a superhydrophobic and superadhesive surface are reported regarding their water immobilization, antibacterial performance, and deodorization. With numerous regular oriented pores on their surface, the as-fabricated electrospun porous PLA/TiO2 composite fibers possessed diameters in the range from 5 µm down to 400 nm, and the lengths were even found to be up to the meters range. The PLA/TiO2 composite fiber surface was demonstrated to be both superhydrophobic and superadhesive. The size of the pores on the fiber surface was observed to have a length of 200 ± 100 nm and a width of 150 ± 50 nm using field-emission scanning electron microscopy and transmission electron microscopy. The powerful adhesive force of the PLA/TiO2 composite fibers toward water droplets was likely a result of van der Waals forces and accumulated negative pressure forces. Such a fascinating porous surface (functionalized with TiO2 nanoparticles) of the PLA/TiO2 composite fiber scaffold endowed it with multiple useful functions, including water immobilization, antibacterial performance, and deodorization. [ABSTRACT FROM AUTHOR]

Micro-arc oxidation (MAO) is widely applied to improve the corrosion resistance of Mg alloys by forming a ceramic passivation film on their surface. The high cohesive strength and randomly distributed micro-porous structure of MAO films have significantly expanded their operation scope, serving as the base or bonding layer for composite or multi-functional coatings. However, mechanical scratches or impacts during installation and service periods can damage the protective performance of MAO films, leading to local corrosion or the rapid loss of mechanical integrity in Mg alloys. Therefore, the development of MAO coatings with self-healing properties has been extensively studied in recent decades. This paper aims to illustrate the gaps between the anti-corrosion characteristics and self-repairing mechanisms dependent on the oxide composition or porous structure of MAO films. The progress in preparation and the principle of inhibitor loading in self-healing functional MAO-based composite coatings are summarized, and future directions are highlighted. [ABSTRACT FROM AUTHOR]

Solar selective absorption films based on anodic aluminum oxide (AAO) photonic crystals were prepared by an anodization under periodic current-pulses, subsequently with an alternating current electrodeposition of Co and Ag in sequence. The phase structure, microstructure, and solar selective absorption properties of the Co–Ag electrodeposited film were investigated in comparison with a Co electrodeposited counterpart. Moreover, the stability of the properties against thermal annealing was examined for the two films. A one-dimensional photonic crystal structure was verified for the AAO part in both films, with the first-order photonic bandgap occurring at around 4 μm, while the metals were confirmed to be deposited at the bottom of the AAO part in the form of nanoparticles. For the Co–Ag electrodeposited film, the Ag nanoparticles were deposited over those of Co. The Ag electrodeposition not only was contributive to the solar selective absorption properties, but also substantially improved the stability of the properties against thermal annealing. The Co–Ag electrodeposited film exhibited an infrared emissivity of 0.12, a solar absorptivity of 0.94, and a spectral selectivity of 7.83 before experiencing thermal annealing, while retained a decent spectral selectivity of 6.00 after being annealed in air at 300 °C for 24 h. • An AAO photonic crystal structure was constituted under periodic current-pulses. • The first-order photonic bandgap was verified to be located at around 4 μm. • The Ag in the Co–Ag electrodeposited film was deposited over the Co. • The Ag electrodeposition benefited the solar selective adsorption properties. • The Ag electrodeposition improved the thermal stability of the properties. [ABSTRACT FROM AUTHOR]

In this work, diphasic mullite (3Al 2 O 3 ·2SiO 2) nanofibers with good homogeneity were prepared by electrospinning method. Aluminum nitrate (AN) and aluminum isopropoxide (AIP) were used as alumina sources, commercial colloidal silica as silica source, and polyvinyl alcohol (PVA) as polymer additive. Precursor nanofibers with continuous and uniform structures were acquired at mass ratio of PVA to precursor sol from 0.06 to 0.09. γ- Al 2 O 3 phase was obtained at 878 °C and mullite phase formed at 1322 °C upon heating of the precursor under air atmosphere. Calcined samples suggested mullite as dominant phase at 1300 °C and amorphous SiO 2 could even exist at 1400 °C. As-prepared nanofibers possessed continuous structures with subequal average diameters at 900–1200 °C. However, such morphological characteristics were lost at temperatures above 1300 °C due to rapid growth of crystal grains. Al and Si elements were uniformly distributed in fibers and mixed at nanoscale, confirming homogeneity and diphasic features of nanofibers. [ABSTRACT FROM AUTHOR]

Atomic diffusion by the vacancy defect of L12-Al3M (M = Sc, Zr, Er, Y) was investigated based on a first-principles calculation. The point defect formation energies were firstly evaluated. Then, the migration energy for different diffusion paths was obtained by the climbing-image nudged elastic band (CI-NEB) method. The results showed that Al atomic and M atomic diffusions through nearest-neighbor jump (NNJ) mediated by Al vacancy (VAl) were, respectively, the preferred diffusion paths in Al3M phases under both Al-rich and M-rich conditions. The other mechanisms, such as six-jump cycle (6JC) and next-nearest-neighbor jump (NNNJ), were energetically inhibited. The order of activation barriers for NNJ(Al-VAl) was Al3Zr < Al3Y < Al3Er < Al3Sc. The Al3Sc phase had high stability with a high self-diffusion activation barrier, while the Al3Zr and Al3Y phases were relatively unstable with a low self-diffusion activation energy. Moreover, the atomic-diffusion behavior between the core and shell layers of L12-Al3M was also further investigated. Zr atoms were prone to diffusion into the Al3Y core layer, resulting in no stable core-shelled Al3(Y,Zr), which well agreed with experimental observation. [ABSTRACT FROM AUTHOR]

Micro-arc oxidation (MAO) technology, as an efficient and widely used technology, can fabricate a ceramic film on magnesium (Mg) alloys in situ to significantly improve corrosion resistance. The study aims to investigate the effect of voltage modes on the preparation and performance of MAO coating on Mg alloys. The scanning electron microscope, X-ray diffractometer, potential dynamic polarization, and electrochemical impedance spectroscopy measurements were applied for characterizing the microstructure, composition, and corrosion resistance of the MAO film, respectively. The results revealed that employed 300/350 V step-up mode, the MAO film showed a more uniform distribution of surface micro-pores, fewer micro-cracks and denser inner layer, lower corrosion current density (1.871 × 10−3 mA·cm−2), and higher electrochemical impedance value, compared to other voltage treated parameters. Therefore, it could be concluded that the step-up voltage parameters are conducive to the optimization of microstructure, improvement of corrosion resistance of MAO coating, and reduction of the energy consumption during processing. [ABSTRACT FROM AUTHOR]

A novel anode for solid oxide fuel cells (SOFCs), consisting of a Ruddlesden-Popper compound, La 0.6 Sr 1.4 Fe 0.4 Cr 0.6 O 3.8 , with in situ exsolved α-Fe nanoparticles (RP-LSF + Fe), is prepared from the phase conversion of the La 0.3 Sr 0.7 Fe 0.7 Cr 0.3 O 3-δ (LSFCr-3) perovskite under humid H 2 at 800 °C. On the surface of the RP-LSF + Fe anode, Fe cations are presented to be a mixture of Fe 2+ and Fe 3+ , of which the average valence is lower than that in the bulk (Fe 3+ ). The coverage of atomic hydrogen on the RP-LSF + Fe anode is over 0.8 in the pH 2 range of 0.017–0.27 atm, implying a significant effect of these small amount (∼8 mol% on the surface) of exsolved Fe nanoparticles (∼200–300 nm) on promoting the dissociative absorption of H 2 . The charge transfer resistance is found to be closely related to the concentration of surface oxygen vacancies of the oxide matrix. The addition of catalytic amount of Ni (1–3 wt.%) greatly improves the fuel flexibility of the RP-LSF + Fe anode. Furthermore, it contributes to acceleration the phase conversion of the LSFCr-3 perovskite and reduced time for in situ preparation of the RP-LSF + Fe anode. The RP-LSF + Fe anode with 2.7 wt.% Ni exhibits a stable cell performance under 2.7%H 2 O+1:1-(H 2 :CO) and 2.7%H 2 O + CH 4 for ∼30 h. It costs shortest time (30 h) to reach a stable cell voltage of 0.76 V at a galvanostatic current density of 0.25 A/cm 2 under humid H 2 , which is clearly an active and stable anode material for SOFCs. [ABSTRACT FROM AUTHOR]

Renewable and low-cost biochar's intrinsic porous structure limitations make its porous structure mediation highly significant for performance enhancement. We employ graphene oxide (GO) as an additive at a low dosage for the deed-leaf-derived biochar's microporous structure mediation to promote the wastewater treatment ability toward a typical antibiotic pollutant - tetracycline hydrochloride (TCH). While KOH-based activation enables biochars with a microporous structure and improved graphitization, GO transforms part of micropores of such activated biochar into mesopores (i.e. forming hierarchical porosity), driven by the thermal pyrolysis of oxygen groups enriched on GO. The GO additive-induced process overcomes the loss of surface resulted from conventional pore widening, promoting mass transport as well as improving the accessibility to pore interiors and compatibility for large-size contaminant molecules. The increase of the sp2-to-sp3 carbon ratio from 0.59 to 0.79 with GO incorporation facilitates π-π stacking interactions with aromatic pollutants (including TCH and organic dyes), which are more critical than the electrostatic attraction and hydrogen bonding interactions. Apart from superior adsorption capacities of 193.43 and 336.70 mg/g obtained at 303 and 313 K, respectively, the graphene-modified hierarchically porous biochar is recyclable, reusable, resistant to interfering metal cations, and universal for binding a range of organic pollutants bearing different charge states, demonstrating equilibrium adsorption capacities of 186.58, 190.38, 268.43, and 254.88 mg/g for TCH, methylene blue, Rhodamine B, and methyl orange, raised by 26.8%, 41.6%, 32.1%, and 105.3%, respectively, compared to the counterpart without GO-enabled micropore widening. The greater adaptability to different-size pollutants presents higher practical application viability. [Display omitted] • GO additive empowered the widening of microporous biochar from 3.0 to 3.3 nm. • GO additive modification improved the sp2-to-sp3 carbon ratio from 0.59 to 0.79. • GO additive incorporation promoted tetracycline capturing capacity to 336.70 mg/g. • The biochar-based adsorbent modified with GO was reusable, tolerant and universal. • π-π stacking interactions drove the efficient adsorption of pollutants. [ABSTRACT FROM AUTHOR]

As a representative composite metal oxide belonging to a perovskite, strontium titanate (SrTiO3) possesses the merits of chemical stability, low toxicity and low cost, endowing it with significant application potentials in environmental remediation, clean energy generation and valuable chemical production from greenhouse gas conversion. However, the pure-phase SrTiO3 suffers from many fatal weaknesses, especially the wide energy bandgap and low photoexcited electron–hole pair separation efficiency, thus limiting its photocatalytic performance and large-scale applications. To address this issue, researchers have made great efforts to modify the electronic and physicochemical structure of SrTiO3. In particular, doping treatments have attracted considerable attention, but some problems still block effective doping, while impropriate doping might worsen the photocatalytic performance of SrTiO3 by introducing the photogenerated hole–electron pair recombination centres. Consequently, many challenges remain for this research topic that is undergoing an intense study. This short review presents the hot spots of appropriate doping treatments of SrTiO3 for photocatalytic performance enhancement over recent years. Different kinds of doping species are systematically discussed. The current problems that remain are summarized and analysed, and the perspectives for the rational doping of SrTiO3 are presented. [ABSTRACT FROM AUTHOR]

Although g-C 3 N 4 (CN) materials have been extensively explored for the photocatalytic degradation of organic pollutants, their weak response to visible light and fast recombination of photoexcited electron-hole pairs restrain their practical applications. Herein, we deeply mediated the CN's energy-band structure, morphology, and surface properties by non-metal (P) and metal (Mo) co-doping based on the thermal treatment of a phosphomolybdic acid hydrate and dicyandiamide mixture in a straightforward one-step manner. Meanwhile, cyano groups and nitrogen vacancies were generated as a result of the co-doping, and the resulting P, Mo co-doped CN (PM-CN) exhibited thinner layers, smaller sizes, and superior visible-light harvesting capacity and charge separation efficiency. Consequently, highly active PM-CN was obtained for photocatalytic tetracyclines (TC) degradation, and the rate was calculated to be 0.01 min−1, 3.3 times greater than that of the pure CN, outstripping the single P- and Mo-doped counterparts. A free radical scavenging test demonstrated that the reactive species •O2− and h+ were critical in TC degradation. The present work is expected to shed light on co-doping CN with non-metal and metal elements to obtain high-performance, visible-light-responsive photocatalysts for practical environmental remediation. [ABSTRACT FROM AUTHOR]

Layered double hydroxide (LDH) films have attracted extensive attention in Mg alloy anti-corrosion due to their unique physical barrier function and ion exchange performance. However, most of the LDH films on Mg alloy have problems of harsh preparation conditions, poor anti-corrosion stability, and poor adhesion. In this paper, a typical Li–Al-alanine (Ala) LDH film has been successfully prepared on AZ91D Mg alloy surface under milder conditions using multi-arc ion plating and in-situ dipping for the first time. Then an improved vacuum impregnation further modified the Li–Al-Ala LDH film in an ethanol solution of stearic acid (SA) to improve its protective stability. The potentiodynamic polarization curves and electrochemical impedance spectra (EIS) showed that the Li–Al-Ala LDH/SA film's corrosion resistance is more than three orders of magnitude higher than that of the blank Mg alloy in 3.5 wt% NaCl, showing a highly increased corrosion resistance. The long-term immersion experiments found that the surface structure and corrosion resistance of the Li–Al-Ala LDH/SA film did not change much after immersion in 3.5 wt% NaCl for 432 h. The bonding force between the film and the Mg alloy substrate can reach grade 0 based on the standard from International Standardization Organization (ISO). And the hydrophobicity of the film can remain stable with the water contact angle (WCA) being steady at about 140° after a certain distance of external abrasion, showing excellent mechanical wear resistance. The study provides a new milder approach to fabricating superhydrophobic LDH films with durable anti-corrosion resistance, good adhesion, and mechanical stability on Mg alloy surface. [ABSTRACT FROM AUTHOR]

Polysilazane and platinum were adopted to enhance the thermal stability of silicone rubber. The effect and mechanism of polysilazane and platinum on enhancing thermal stability were investigated via thermogravimetry, scanning electron microscopy-energy dispersive X-ray spectrometry, thermogravimetry-Fourier transform infrared spectrometry, and Fourier transform infrared spectrometry. Remarkable synergism between polysilazane and platinum was found in enhancing thermal stability of silicone rubber. When 1.34 wt% polysilazane and 8 ppm platinum were added, the degradation temperatures were elevated. Furthermore, the thermal residues of silicone rubbers were increased from 30–45 to 66–76 wt%, and maximum degradation rates were reduced from 8.81–15.8 to 4.55–5.02 wt%/min. Besides, silicone rubber demonstrated excellent shape retention at high temperature in the presence of polysilazane and platinum. The mechanism may be that platinum cooperated with polysilazane and efficiently catalyzed radical crosslinking between polysilazane and silicone chains. As a result, a tightly crosslinked network was developed, and degradation of silicone rubber was suppressed. [ABSTRACT FROM AUTHOR]

Anodic aluminum oxide (AAO) photonic crystal films with Sn nanoparticles electrodeposited at the bottom were prepared using a pseudo-sine-pulse anodization technique followed by an alternating current electrodeposition. Moreover, a pore-widening post-treatment was performed for the Sn electrodeposited films. The phase structure, microstructure and structural color properties of the specimens with different preparation histories were examined. The Sn electrodeposition enabled production of brightly colored AAO photonic crystal films after a short-duration anodization (40 anodization cycles) in a sulfuric acid electrolyte solution at a temperature (around 20 °C) near to room temperature, which is technology-friendly relative to the conventional anodization conditions when using sulfuric acid electrolyte solutions, e.g., after 80–300 anodization cycles at around 0 °C. Moreover, the pore-widening treatment was demonstrated to be convenient and controllable in tuning the porosities and structural color properties of the Sn electrodeposited films. The peak wavelengths of the reflectance spectra were nearly linearly blue-shifted from 681 to 574 nm with increasing pore-widening time from 0 to 8 min, concomitant with a structural color change from bright-red to yellowish-green. Meanwhile, the peak reflectances were linearly enhanced from 59 to 84%, corresponding to an increase of the brightness of the films. The linearly varied peak wavelengths and peak reflectances were related to a linear increase of the porosities of the stem and branched layers in the films with pore-widening time. • Sn electrodeposition enabled producing colored films via anodizing in sulfuric acid. • The porosities of the two AAO layers were linearly increased with pore-widening time. • The porosity contrast between the two layers became larger with pore-widening time. • The porosity change led to a linear variation of the structural color properties. • The results exemplified an easy strategy to controllably tune the structural colors. [ABSTRACT FROM AUTHOR]

AgNbO 3 lead free AFE ceramics are considered as one of the promising alternatives to energy storage applications. In the majority of studies concerning the preparation of AgNbO 3 AFE ceramics, an oxygen atmosphere is required to achieve high performance, increasing the complexity of the fabrication process. Herein, a facile approach to preparing AgNbO 3 ceramics in the ambient air was reported, in which the AgNbO 3 ultrafine powder with stable perovskite structure was synthesized by hydrothermal method instead of the conventional ball milling process, leading to a lower temperature of phase formation and thus smaller grain size. The resulting ceramics sintered at 940 °C displayed high breakdown strength (216 kV/cm) and a recoverable energy density of 3.26 J/cm3 with efficiency of 53.5 %. Also, the high thermal stability of recoverable energy density (with minimal variation of ≤20 %) and efficiency (≤ 10 %) over 30–150℃, enables AgNbO 3 ceramics achieved to be a promising candidate for energy storage applications. [ABSTRACT FROM AUTHOR]

In this work, novel graphitic sheets with ripple-like folds (GSRFs) are synthesized from cheap resin via a facile route. The obtained GSRFs are used as a cladding layer for LiNi0.8Co0.15Al0.05O2 (NCA) particles to construct a GSRF@NCA composite cathode. Electrochemical testing for GSFR@NCA exhibits better cycling and C-rate performance than those of original NCA. Moreover, the capacity retention (85%) of the full-cell (GSFR@NCA versus graphite) is much higher than that (79%) of the full-cell (NCA versus graphite) after 400 cycles. Most importantly, this approach allows the preparation of GSFR@NCA with highly promising applications as a cathode for high-energy-density lithium-ion batteries, since in this contribution just simple equipment and a precursor with low cost are involved. [ABSTRACT FROM AUTHOR]

Cu-Fe-P immiscible alloys characterized by heterogeneous lamellar structure were manufactured by laser powder bed fusion (LPBF) and the deformation behavior of LPBF-produced immiscible alloys was investigated systematically. When the linear energy density of 133 J/m is adopted during LPBF, the immiscible alloy exhibits the highest compressive strength (∼1 GPa) and engineering strain (∼27%). The high strength of the LPBF-produced immiscible alloy is attributed to the heterogeneous lamellar structure including the interconnected Fe 2 P layer and nano-Fe 2 P particles as "hard" phase dispersed in the ε-Cu matrix as the "soft" phase. Moreover, the good ductility is attributed to the fine ε-Cu grains as "soft" phase precipitated within the lamellar Fe 2 P due to the secondary liquid phase separation (SLPS). This "soft-hard-soft" heterogeneous microstructure can effectively delay crack growth to exhibit excellent mechanical properties in the LPBF-produced immiscible alloys. [Display omitted] • Heterostructure "soft-hard-soft" Cu-Fe-P immiscible alloys are produced by LPBF. • Cu-Fe-P immiscible alloy exhibits excellent strength-ductility synergy when the LED is 133 J/m. • NT-Cu grain in Fe 2 P phase can block the dislocation motion to enhance the strength. • ε-Cu grains produced by SLPS in the interconnected Fe 2 P layer can delay crack propagation to enhance the ductility. [ABSTRACT FROM AUTHOR]

The β-type Ti35NbxCu alloys (x = 0, 1, 3, 5, and 7 wt%) were produced by laser powder bed fusion (LPBF) and the influence of Cu content on the microstructure and mechanical properties was studied. The results indicate that when the content of Cu is less than 3 wt%, Cu can diffuse completely into the Ti matrix to form solid solution without element segregation. Moreover, the elastic modulus of Ti35Nb1Cu alloy (49.1 ± 1.6 GPa) is reduced by 33 % compared to that of Ti35Nb alloy (73.2 ± 1.4 GPa). When the content of Cu exceeds 3 wt%, the eutectoid reaction is activated during the cyclic heating and rapid cooling of LPBF, and the partially supersaturated β phase is transformed into nano-scale α and Ti 2 Cu phases (β→α+Ti 2 Cu). Nano-scale Ti 2 Cu particles precipitated along β grain boundary results in a pinning effect, which inhibits the growth of β grain, hinders dislocation movement, and improves the strength of the alloy. However, when the content of Cu is 7 wt%, the dislocation density (4.179 × 1015 m−2) and the ratio of brittle phase Ti 2 Cu (8.5 %) are too high, and the stress concentration caused by the initiation of inherent micro-cracks are the main reason for the tensile brittle fracture of Ti35Nb7Cu alloy. As such, the Ti35Nb5Cu alloy has the highest tensile strength of 867.3 ± 24 MPa and the elongation reaches 11.7 ± 0.5 %. Therefore, solution strengthening of Cu, fine grain strengthening of β, dislocation strengthening, and precipitation strengthening of Ti 2 Cu are the main reasons for the excellent comprehensive mechanical properties of Ti35Nb5Cu alloy. • LPBF-produced Ti35NbxCu alloys have uniform distribution of elements. • Adding Cu to Ti–Nb alloy can refine grains and reduce elastic modulus. • LPBF-produced Ti35NbxCu alloys have only half the elastic modulus of Ti6Al4V alloy. • Ti35Nb5Cu alloy exhibits an enhanced strength-ductility synergy. [ABSTRACT FROM AUTHOR]

The mechanical, thermal and electrical properties of 8 types of common Al x TM y (TM = Sc–Zn, Y–Cd, Hf–Hg) intermetallics in Al based alloys at various temperatures and pressures have been investigated by combining first-principles calculations with the Debye model. The results clearly show that the stability and mechanical property are closely related to the types of configurations and TM elements. The electronic structure for AlRh and AlCd alloys are used to study the characteristics of stable compounds, and it is found that more transferred electrons will make the lattice mismatch δ larger. The Cauchy pressure C 12 – C 44 and electric local function (ELF) present underlying characteristics of bonds and physical mechanisms. Further, the Helmholtz free energies F of both Al bulk and stable Al x TM y intermetallics are decreased with increasing temperature, while the entropy S , heat capacity C V and coefficient of expansion a T show the opposite trends. And the smaller F leads to the lower a T ; that is the compounds constitute of elements of IB ∼ IVB have larger F and a T , while the compounds with VB ∼ VIIB possess smaller F and a T. In short, all calculated parameters in this work show the same change with the atomic number in for three periods 3-5d, indicating that the structure of the TM valence electron layers are the main reason for the underlying mechanisms. This work is helpful for the study of high-performance of structural Al-based alloys. • The ΔHf is closely related to the types of crystal configurations and TM elements, and so is the mechanical properties. • The δ of more than 60 % of precipitates is larger than 4 %. And the δ of all structures first decreases, and then increases in the same cycle with the increase of atomic number, except for AlTM2 and Al11TM3. Clearly, more transferred electrons will make the δ larger. • The B, G and E of most Al-TM compounds are improved, except for D022-Al3Hg, the B of B2–AlY, L12-Al3(Zn, Y), D019-Al3Y, Al(Sc, Y)2 and Al11Y3, and the E of AlY2. The Cauchy pressure of C12–C44 demonstrate only ∼23 % of the compounds show directional covalent characteristic, and the compounds with d5-8 shells show stronger metallic characteristic. • About 5.31 % of the stable compounds present uniform deformation, and 26.55 % of the stable intermetallic particles show brittleness; the B/G and ν of 31.86 % compounds are larger than that of Al. The valence electron configurations directly decide ν and B/G of AlxTMy, the same as B, G and E moduli. • The Helmholtz free energy F of all stable Al-TM compounds including Al bulk is slightly decreased with increasing temperature. With the increase of temperature, the increasing velocity of entropy S continuously slowed down; and the constant volume heat capacity CV of compounds increase drastically at 0–300 K, and nearly unchanged elevated temperatures. The aT of all Al-TM compounds including Al increases fast and nearly linearly at 0–300 K, and increases exponentially after 600 K. [ABSTRACT FROM AUTHOR]

The 2 wt% Al 2 O 3 reinforced CoCrAlYTa coatings (referred to as 2Al 2 O 3 -CoCrAlYTa) were manufactured by laser-induction hybrid cladding. And the oxidation behavior of the coatings was investigated using a thermogravimetric analyzer (TGA) at different oxidation temperatures (950 °C, 1000 °C, 1100 °C, and 1200 °C) in an air atmosphere with a test time of 200 min. The composition and microstructure of the oxide scales formed at different temperatures were characterized and investigated. Additionally, the microstructure evolution of the coating, failure mechanism of the oxide scales, and elemental diffusion at the different temperatures were also discussed. It was found that after oxidation, Al depleted zones appeared in the 2Al 2 O 3 -CoCrAlYTa coatings. When oxidation temperature was 950 °C, fine-equiaxed oxide grains were formed on the coating. Moreover, at 950 °C, 1000 °C, and 1100 °C, the oxide scales were intact, and no large voids were found in the oxide scale/coating interface. As the temperature reached 1200 °C, the oxide scale formed on the surface of the coating became thicker and consisted of an outer layer of fine equiaxial crystals and an inner layer of coarse columnar crystals, and large voids developed at the oxide scale/coating interface, causing the oxide scales to delaminate from the coating. [Display omitted] • 2Al 2 O 3 -CoCrAlYTa (ODS) coatings were produced by laser-induction hybrid cladding (LIHC). • At 950 °C, 1000 °C and 1100 °C, a continuous Al 2 O 3 scale formed on the coatings surface. • The rapid outward-diffusion of Al caused the formation of voids at the scale/coating interface at 1200 °C. • The excessive internal stress superimposed massive voids leads to the cracking and delamination of scale at 1200 °C. [ABSTRACT FROM AUTHOR]

With three distinct layers, multicolor, hierarchical nanocomposite films based on anodized aluminum oxide (AAO) were fabricated on the 6063 aluminum alloy surface by anodizing and alternating current electrodeposition. The impact of the electrolysis time on the nanostructures and optical properties of the as-grown film was investigated. It was found that with the extension of electrolysis time, the sample color could be varied from gray, yellow, red, blue, to green, realizing almost full-spectrum colors of the AAO-based films in the visible light range. The nanostructure characterizations and the UV–Vis reflectance spectroscopy of the AAO-based films showed that the thickness of the bottom one (i.e., layer 3) of the three layers was dictated by the electrolysis time over the range of 55–145 s, corresponding to the thickness from 135 to 264 nm. Additionally, the optical pathway of the AAO-based film with hierarchical composite nanostructures was analyzed. An increase in the layer 3 thickness would cause a shift in the peak wavelength in the corresponding reflectance spectra, conforming to the Bragg-Snell formula. The colors of AAO films were speculated to originate from constructive interference between the light reflected from the layer 1-layer 2 interface and the light reflected from the layer 3-aluminum alloy substrate interface. Image 1 • Growing AAO-based, hierarchical nanocomposite films on the aluminum alloy surface. • Studying the electrolysis time impact on the nanostructures and optical properties. • Electrolysis time is strongly correlated with the surface color appearing. • The typical layer thickness within the hierarchical nanocomposite was finely tuned. • Optical pathway and coloring mechanism of the nanocomposite film were analyzed. [ABSTRACT FROM AUTHOR]

• Synthesized (Co 9 S 8 @C-NCNTs) using polypyrrole (PPy) tubes and ZIF-67 as the precursors. • Co 9 S 8 nanoparticles were coated by carbon layer and attached on the carbon tubes. • Co 9 S 8 @C-NCNTs exhibits excellent electrochemical performance as the material of LIBs. Nitrogen doped carbon nanotubes supported Co 9 S 8 nanoparticles (Co 9 S 8 @C-NCNTs) was successfully prepared by solid state sulfurization reaction. As a result, the capacity, rate performance and cycling stability of Co 9 S 8 @C-NCNTs are obviously enhanced when it is used as anode material for LIBs. Co 9 S 8 @C-NCNTs composite exhibits a reversible capacity of 727 mAh g−1 after 100 cycles at a current density of 0.5 A g−1 and excellent rate performance (589 mAh g−1 after 500 cycles at 2 A g−1). This work provides a succinct and effective approach to prepare high-performance LIBs anode materials using metal organic framework (MOF) as precursor. [ABSTRACT FROM AUTHOR]

Decoration of TiO 2 with plasmonic Au nanoparticles is attracting extensive research for enhancing photoelectrochemical water splitting efficiency. In this work, we propose a double light beam method to investigate enhance effect of Au nanoparticles on the TiO 2 single crystals. With double light beam method, it was found out that the photocurrent produced by Au nanoparticles was strongly decreased 3.5–4 times by inter-band transition of TiO 2. The amplitude of open circuit potential transient was decreased from 100 mV to 12 mV by the inter-band transition. By analysis with Mott-Schottky plotting, photo-generated Au hot hole concentration decreased from 1.28 × 1019 cm−3 to 1.02 × 1018 cm−3 was revealed. Potential independent photocurrent of Au NPs was observed, indicating that the photocurrent produced by Au NPs was determined by the generation rate of Au hot holes. The underlying reason for the suppressive effect of inter-band transition on the photocurrent of Au nanoparticles was pointed to the strongly decreased photo-generated Au hot hole concentration. Image 1 • A double light beam method was proposed to study the enhanced photocurrent of Au. • Suppressed photocurrent of Au by inter-band transition of TiO 2 was observed. • Decreased generation of Au hot holes was attributed to the suppressed photocurrent. [ABSTRACT FROM AUTHOR]

A calcium-doped ceria (Ce 1-x Ca x O 2−δ , 0 ≤ x ≤ 0.3) has been applied as a ceramic support in NiMo-based catalysts for an internal reforming tubular solid oxide fuel cell running on isooctane. Introducing calcium into the CeO 2 -based ceramic was found to improve conductivity of Ce 1-x Ca x O 2−δ. The Ce 0.9 Ca 0.1 O 2−δ (x = 0.10) sample exhibited an optimum conductivity of 0.045 S cm−1 at 750 °C. The transport of oxygen ions in Ce 1-x Ca x O 2−δ promoted the catalytic partial oxidation of isooctane in the NiMo–Ce 1-x Ca x O 2−δ catalyst, which increased the fuel conversion as well as H 2 and CO yields. As a result, the NiMo–Ce 0.9 Ca 0.1 O 2−δ (x = 0.10) catalyst exhibited a high isooctane conversion of 98%, and the H 2 and CO yields achieved 74% and 83%, respectively, for reforming of isooctane and air at the O/C ratio of 1.0 at 750 °C. Furthermore, the NiMo–Ce 0.9 Ca 0.1 O 2−δ catalyst has been applied as an internal reforming layer for an inert-substrate-supported tubular solid oxide fuel cell running on isooctane/air. Due to its high reforming activity, the single cell presented an initial maximum power density of 355 mW cm−2 in isooctane/air at 750 °C and displayed stable electrochemical performance during ~30 h operation. These results demonstrated the application feasibility of the NiMo–Ce 0.9 Ca 0.1 O 2−δ catalyst for direct internal reforming solid oxide fuel cells running on isooctane/air. Image 1 • NiMo–Ce 0.9 Ca 0.1 O 2−δ is found to be an effective reforming catalyst for SOFC. • Conductivity of Ce 0.9 Ca 0.1 O 2−δ support is related to the reforming activity. • Oxygen transport property promotes the catalytic partial oxidation of isooctane. • Good performance stability is obtained for SOFC running on isooctane/air. [ABSTRACT FROM AUTHOR]

The noxious clenbuterol misapplied as the feed additive has posed an enormous threat to humans who actively rely on the food chains with high potential of contamination by clenbuterol, such as pork and beef. It is, therefore, highly desirable to develop novel materials and strategies for dealing with the clenbuterol. Herein, functional polymer microspheres prepared by Pickering emulsion polymerization were explored for the selective enrichment of the clenbuterol, and their structure and oxygen functionalities could be tailor-made by a molecular imprinting process. The clenbuterol imprinting was adequately demonstrated to not only increase the particle size (~52 nm vs. ~42 nm) and create cavities for the accommodation of the clenbuterol molecules, but also reduce the oxygen functionalities of the resulting molecularly imprinted polymer microspheres (MIPMs) by approximately 4 at.%, which is believed to correlate with the high specificity of the MIPMs. Various characterization methods were employed to evidence these findings, including scanning electron microscopy, BET measurements, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and elemental mapping examination. More importantly, the MIPMs showed a markedly superior enrichment capability towards clenbuterol to the counterpart, that is, non-molecularly imprinted polymer microspheres (NIPMs). Compared to the NIPMs without specificity for clenbuterol, the MIPMs exhibited an impressive selectivity to clenbuterol, with the relative selectivity coefficient (k′) values largely exceeding 1, thus corroborating that the useful molecular imprinting led to the generation of the binding sites complementary to the clenbuterol molecule in the size and functionalities. The MIPMs were also employed as the stationary phase to fabricate molecularly imprinting solid-phase extraction column, and the spike recovery was demonstrated to be not significantly decreased even after nine cycles. Furthermore, the reliability of the method was also evidenced through the comparison of the MIPMs prepared from different batches. [ABSTRACT FROM AUTHOR]

Limited slip systems of α structure always play a major role in hindering strength-ductility synergy improvement of titanium (Ti) alloys. To overcome the strength-ductility trade-off of Ti alloys, heterostructure is introduced into Ti6Al4V- x Cu (x = 0, 1, 3, 5 wt.%) alloys produced by laser powder bed fusion (LPBF), and the formation mechanism and deformation behavior of heterostructures were investigated. The results showed that the monolithic α' in the LPBF-produced Ti6Al4V- x Cu (wt%) alloys is decomposed into dual α and α" after heat treatment at 600–900 °C through α' → α + Ti 2 Cu → matastable phase → α + α". The multistage transformation of α' to α and α" is driven by thermal activation (temperature > 800 °C), Cu addition and rapid cooling of water quenching. The heterostructure with α and α" in the LPBF-produced Ti6Al4V-5Cu alloy after heat treatment at 800 °C results in high tensile strength (∼1.3 GPa) and large elongation (∼15%). The enhanced strength-ductility synergy is attributed to the decomposition of brittle α' and Ti 2 Cu, as well the soft-hard heterostructure of α" and α. Moreover, the deformation twins (DTs) in α" and the heterogeneous interfaces of α and α" can also improve the strength and ductility of the LPBF-produced Ti6Al4V- x Cu alloys. These findings elucidate the influence of heterostructure (α and α") on strength and ductility, which is helpful for designing Ti alloys with excellent mechanical properties. [Display omitted] [ABSTRACT FROM AUTHOR]

A hollow–structured NiCo Hydroxide/carbon nanotube composite is prepared using a facile epitaxial growth route based on the construction of a new 3D hard template and a subsequent etching treatment. With a controlled etching procedure, the hard template Cu 2 O nanoparticles gradually dissolve, which results in the formation of a hollow structured NiCo hydroxide/carbon nanotube composite. Owing to a synergetic contribution from the hollow structured NiCo Hydroxide and the intersected carbon nanotube network, the NiCo hydroxide/carbon nanotube composite electrode exhibits a significant enhancement in structural stability and displays a higher specific capacitance (1896 and 1479 F g−1 at 1 and 40 A g−1, respectively) in comparison with that of the NiCo hydroxide. An asymmetric supercapacitor consisting of hollow structured NiCo Hydroxide/carbon nanotube composite shows a high specific capacitance of 139.3 F g−1 at 1 A g−1, a maximum energy density of 37.9 Wh kg−1, and a power density of 7005 W kg−1. The device also maintains 91.6% of its initial specific capacitance and a coulombic efficiency close to 100% after 12,500 cycles at 6 A g−1. This superior performance suggests that the prepared hollow structured Hydroxide/carbon nanotube composite has potential for applications as an electrode material in high–performance supercapacitors. Image 1 • Hollow–structured NiCo Hydroxide/carbon nanotube composite was prepared. • The composite exhibited a significant enhancement in structural stability. • The composite showed a high specific capacitance of 139.3 F g−1 at 1 A g−1. • The composite electrode have a high coulombic efficiency and a long cycle life. [ABSTRACT FROM AUTHOR]

Abstract The development of highly efficient and earth-abundant electrocatalysts to replace the rare and expensive noble metal catalysts is currently an important goal of renewable energy research. We report advanced and highly efficient electrocatalysis of oxygen evolution reaction using the cobalt sulfide (Co 9 S 8) nanoparticles embedded in nitrogen, sulfur co-doped graphene (Co 9 S 8 /NSG) hybrid materials, which are obtained by coating Co-based metal-organic frameworks. The frameworks are grown in situ on graphene oxide using a facile pyrolysis method, with polydiaminothiazole, which serves as both a nitrogen and a sulfur source in the system. The prominent synergistic effect of the S, N-co-doped graphene helps to enhance the conductivity of the hybrid, and the Co 9 S 8 provides abundant catalytic active sites as well as mesoporous structure. As a result, the Co 9 S 8 /NSG hybrid materials exhibit outstanding performance in the oxygen evolution reaction and superior stability in alkaline electrolytes. For example, the hybrid materials have a small overpotential of 0.26 V with a Tafel slope of 55 mV dec−1 at a current density of 10 mA cm−2 and they show long-term stability in 1 M KOH. This work provides a general and promising method for the design and synthesis of inexpensive and efficient OER electrocatalysts. Graphical abstract Image 1 Highlights • Polydiaminothiazole provides the N and S co-doped into the carbon. • Co 9 S 8 /NSG hybrid electrocatalyst was prepared by a facile pyrolysis method. • Overpotentials of 260 mV at a current density of 10 mA cm−2. • Low tafel slope of 55 mV dec−1. [ABSTRACT FROM AUTHOR]

Abstract The hollow Fe p -reinforced Cu-matrix homogeneous immiscible alloys were successfully produced by the combination of Kirkendall effect and laser powder deposition. The microstructure and corrosion resistance depended not only on chemical composition, but also on cooling rate. When Fe content decreased from 30% to 12% and cooling rate decreased from ∼2 × 104 to ∼1 × 104 K/s, the demixing was eliminated, the mixed Fe p (α-Fe/γ-Fe) were uniformly embedded within ε-Cu matrix and the "single-void" Fe p transformed into the "multi-voids" Fe p. The "multi-voids" immiscible alloy exhibited higher corrosion resistance than the "single-void" immiscible alloy and Brass after immersing for 5 days. Highlights • Kirkendall-effect induces hollow Fe p within immiscible alloys of laser powder deposition. • Homogeneous immiscible alloys are obtained with decreasing of Fe content. • "Single-void" Fe p transforms into "multi-voids" Fe p with decreasing of cooling rate. • "Multi-voids" immiscible alloy exhibits higher corrosion resistance than Brass after immersion. [ABSTRACT FROM AUTHOR]

Abstract Two-electrode configuration is preferably used in practical application of various photoelectrochemical systems, such as green fuel production and cathodic protection. Photo electrodes are extendedly studied but the effects of the dark electrodes on overall performance of PEC systems are not experimentally figured out. To address this issue, herein, a novel electrochemical method achieving simultaneous measurement of photocurrent and real-time potential of the photo electrode and the dark electrode is proposed. With this method, the actual band positions and band bending of the photo electrode under photocurrent going through can be determined correctly. By investigating photoelectrochemical hydrogen production and cathodic protection with ZnO photo anodes, it is revealed that the amplitude of photocurrent is not solely determined by the number of light generated electrons on the photo electrode but also strongly affected by their consuming rate for electrochemical reactions on the dark electrode. These applications demonstrate the practicality, reliability and universality of the proposed method for comprehensive understanding the reactions of various photoelectrochemical systems and eventually for their better development. Graphical abstract Image 1 Highlights • Simultaneous measurements of photocurrent and potentials of the photo and dark electrodes have been achieved. • Actual band structure of the ZnO electrode under photocurrent flowing through is determined. • Photocurrent is not solely determined by photo electrode but also affected by dark electrode. [ABSTRACT FROM AUTHOR]

Abstract A promising sensing platform for the ultrasensitive detection of dopamine (DA) has been constructed using MnO 2 nanowires-electrochemically reduced graphene oxide modified glassy carbon electrode (MnO 2 NWs-ErGO/GCE). The proposed MnO 2 NWs-ErGO/GCEs had the large electrochemical active area and relative low charge transfer resistant (R ct). As a result, the response peak current of the MnO 2 NWs-ErGO is about 13 times higher than that of the bare GCE, demonstrating the remarkable electrocatalytic activity toward DA. The electrochemical kinetics revealed that DA oxidation is quasi-reversible reaction coupling with one electron and two protons. Three linear ranges (0.01 μM − 0.10 μM, 0.10 μM − 1.0 μM, and 1.0 μM − 80 μM) were obtained on the MnO 2 NWs-ErGO/GCE, with a low detection limit of 1.0 nM (S/N = 3). Moreover, the response current was almost unaltered even in the presence of 100-fold ascorbic acid (AA) and uric acid (UA), suggesting MnO 2 NWs-ErGO has good selectivity toward DA. Finally, the MnO 2 NWs-ErGO/GCEs were successfully applied to detect DA in the injection solutions and human blood serum samples with high accuracy and good recovery. Graphical abstract Image 1 Highlights • A promising sensing platform toward dopamine based on the MnO 2 NWs-ErGO/GCE was constructed. • The response peak current of MnO 2 NWs-ErGO/GCE is 14 times as compared with that of bare GCE. • A quasi-reversible process coupling with one electron and two protons. • Wide linear response ranges (0.01 μM − 0.10 μM, 0.10 μM − 1.0 μM, and 1.0 μM − 80 μM) and low detection limit (1.0 nM). [ABSTRACT FROM AUTHOR]

Abstract Frequency selective surfaces (FSSs) with periodic smart structures have widespread applications in many areas, especially in electromagnetic wave filters. In this paper, a rapid and high-performance processing technology for large-area FSSs was presented. This novel technology combined laser direct writing lithography (LDWL) with wet chemical etching (WCE) (i.e., LDWL + WCE). Basing on experiments and in the condition of optimal parameters (i.e., 40 mW laser power, 1000 mm/s scan speed, single scan, 20 μm hatch space, pattern-profile scan path, and ferric chloride aqueous solution as etchant) of LDWL + WCE, a large-area (200 × 200 mm2) aperture type FSS with 625 square-loop units was fabricated within 8 min on a FR-4 copper-clad plate (with 12 μm-thickness copper layer). When the same FSS was prepared by commonly-used laser direct ablation (LDA) technology with itself optimal processing parameters, it needed about 62 min (nearly 8 times as much time as the former). Scanning electron microscopy (SEM) and surface probe profilometry analyses showed that the edges of the square-loop patterns fabricated by LDWL + WCE were steeper and smoother, and the FR-4 substrate had no damage. In an anechoic chamber, the electromagnetic wave filtering performances of the as-prepared FSSs were tested, and the results indicated that the FSS fabricated by LDWL + WCE had a bandpass response at 7.08 GHz with a transmittance of 97.75%. Its frequency response curve was in better agreement with the simulation result. The technology of LDWL + WCE also has the potential to rapidly fabricate large-area and/or non-planar FSSs with high performance. [ABSTRACT FROM AUTHOR]

Abstract The Hf 0.5 Nb 0.5 Ta 0.5 Ti 1.5 Zr refractory high-entropy alloy with excellent corrosion resistance in the 3.5 wt% NaCl solution is identified in this work. This refractory high-entropy alloy exhibits much better general corrosion resistance than that of the 316L stainless steel, due to its corrosion current density being about one fifth of that in the latter. Meanwhile, the pitting potential of Hf 0.5 Nb 0.5 Ta 0.5 Ti 1.5 Zr reaches an unusually high value of +8.36 V, much higher than that of reported high-entropy alloys. The superior passivity of Hf 0.5 Nb 0.5 Ta 0.5 Ti 1.5 Zr is accredited to the formation of a single-phase solid solution containing high amount of homogenously distributed passivity-promoting elements, and also the existence of metallic Ta and OH− species in the passive film, which contribute to the high immunity to passive film breakdown. Highlights • Hf 0.5 Nb 0.5 Ta 0.5 Ti 1.5 Zr contains finely distributed passivity-promoting elements. • Hf 0.5 Nb 0.5 Ta 0.5 Ti 1.5 Zr exhibits better general corrosion resistance than 316L SS. • E pit of Hf 0.5 Nb 0.5 Ta 0.5 Ti 1.5 Zr reaches +8.36 V, beating all other reported RHEAs. [ABSTRACT FROM AUTHOR]

Photoelectrochemical chlorine (Cl 2) evolution as the anodic reaction of solar hydrogen production is helpful for increasing the additional value of hydrogen and reducing production cost. In this work, chemically stable TiO 2 nanotubes are used as the photoanodes for photoelectrochemical chlorine and hydrogen production. Oxygen vacancies (V O) are introduced by post-annealing in H 2 /N 2 atmosphere. By controlling the post-annealing temperature, concentration of oxygen vacancies is tuned efficiently. Systematic photoelectrochemical measurements reveal that the oxygen vacancies significantly enhance the PEC performance for Cl 2 production with respect to the pristine TiO 2. The sample post-annealed at 450 °C in H 2 /N 2 achieves the highest Cl 2 production rate of 37.12 μmol h−1 cm−2 with a Faradaic efficiency of 73.2% that resulted in fast degradation of methyl orange at a speed of 5.73 mg h−1 cm−2. Furthermore, photocurrent of the two-electrode cell constructed with the V O -rich TiO 2 is strongly increased by 250%, demonstrating that introducing oxygen vacancies is a promising way for promoting the photoelectrochemical performance for Cl 2 and H 2 production. By careful measuring the Faradaic efficiency of various photoanodes, it is revealed that the strongly boosted up Cl 2 production is owing to enhancing utilization of photogenerated holes via the oxygen vacancies. [Display omitted] • Oxygen vacancies are efficiently introduced to the TiO 2 photoanodes. • Photocurrent is strongly increased by the oxygen vacancies. • Chlorine production with an Faradaic Efficiency of 73.9% was achieved. • The boosted performance is owing to the enhanced utilization of photo-generated holes and electrons. [ABSTRACT FROM AUTHOR]

With the energy crisis and resource depletion nowadays, novel, highly performing, and cost-effective semiconductors are in urgent demand for efficiently harvesting solar energy for photoelectrochemical applications. Herein, this study presents low-cost anatase TiO hollow nanoparticles as prepared by a critical liquid-phase deposition (LPD) processing combined with a hydrothermal reaction and calcination processing, without involving any templates. The additional LPD processing not only makes the resulting samples more visible light responsive, but also results in hollowing the TiO nanoparticles (nanosheets vs. hollow nanoparticles). Importantly, commercial TiO powder is employed as the starting material to achieve the final synthesis of TiO hollow nanoparticles, making it scalable and cost-effective for production and applications. As a by-product, the fluoride, formed during the preparation process, is assumed to play a significant role in hollowing through chemically induced self-transformation and Ostwald ripening, in addition to enhancing the crystallinity. The beneficial structural evolution to the hollow nanoparticles enables the improvement of the photoelectrochemical performance through impressive inhibition of the recombination of the photoelectrons and holes, which is well evidenced by I and EIS (Nyquist plot), as well as by I- V curve and electron lifetime evaluations as for the assembled DSSCs with the prepared TiO hollow nanoparticles under simulated sunlight illumination (50 mW/cm). [ABSTRACT FROM AUTHOR]

The effect of casting pores on the very high cycle fatigue (VHCF) behavior of a directionally solidified (DS) Ni-base superalloy DZ4 is investigated. Casting and hot isostatic pressing (HIP) specimens were subjected to very high cycle fatigue loading in an ambient atmosphere. The results demonstrated that the continuously descending S-N curves were exhibited for both the casting and HIP specimens. Due to the elimination of the casting pores, the HIP samples had better fatigue properties than the casting samples. The subsurface crack initiated from the casting pore in the casting specimens at low stress amplitudes, whereas fatigue crack initiated from crystallographic facet decohesion for the HIP specimens. When considering the casting pores as initial cracks, there exists a critical stress intensity threshold ranged from 1.1 to 1.3 MPa√m, below which fatigue cracks may not initiate from the casting pores. Furthermore, the effect of the casting pores on the fatigue limit is estimated based on a modified El Haddad model, which is in good agreement with the experimental results. Fatigue life for both the casting and HIP specimens is well predicted using the Fatigue Indicator Parameter (FIP) model. [ABSTRACT FROM AUTHOR]

Three novel polydiacetylenes (PDAs) are synthesized through the self-assembly followed by the topochemical polymerization via controllable electrophoretic deposition. All the samples could undergo a multi-step thermochromic process, turning purple and red successively over a wide range from room temperature to above 250 °C. Resulting PDAs are studied by UV–vis, IR, Raman spectroscopies, and chromoisomerism by naked eye visualization; their stabilities by thermogravimetric method, and emission behavior by fluorescence spectroscopy. To study the mechanism of the thermochromic response, temperature-dependent UV–vis spectra, the results of which successfully highlighted the close relationship between chromatic transitions and the conformational changes. [ABSTRACT FROM AUTHOR]

In this study, an anodic aluminum oxide (AAO)-based photonic crystal, with a branched channel structure and deposited Cu-Ni composite nanoparticles, is fabricated for solar thermal absorption. The infrared-wave emission properties can be finely tuned by adjusting photonic band gap of the photonic crystal, facilitating the production of an excellent solar heat-absorbing material. Such a channel structure, as generated by anodic oxidation, possesses layers with high and low porosities, featuring a periodical change. The programmed power source (with periodically changed voltage and hence step-change current) enables sharp alteration of the porosity, forming the AAO-based photonic crystal oxidation film (with a complete photonic band gap). Subsequently, Cu-Ni composite nanoparticles are deposited into the pores of the AAO-based film at an alternating current (AC) frequency under different conditions. The optimized conditions (including periodical oxidation time, voltage, oxidation period, AC deposition voltage, time, and temperature) lead to the generation of a solar heat-absorbing composite coating that exhibits solar absorptance, thermal emissivity, and quality factor reaching values of 0.95, 0.13 and 7.3, respectively. In addition, the composite oxidation coating, with the AAO-based photonic crystal layer, shows a significantly lower thermal emissivity as compared to the counterpart in the absence of the AAO-based photonic crystal layer. [ABSTRACT FROM AUTHOR]

For the first time, this study presents solar photocatalytic processing of the real dye wastes remaining after finishing polyester/cotton (P/C) blends, rather than a pure organic dye solution as widely reported. A commonly used microencapsulation-based one-bath dyeing is investigated systematically, in order to simulate the real dyeing environment and to generate real dye wastes. The generated dye wastes are subsequently tackled by facile cotton fabric-based photocatalytic degradation involving a visible light-active TiO photocatalyst under solar light. Importantly, such a TiO photocatalyst is prepared without any calcination, doping, or coupling with plasmonic metal nanoparticles or narrow-band-gap semiconductors. As a result, the present visible light-responsive cotton fabric-based photocatalytic degradation of the simulated real dye wastes is expected to stimulate various industries for achieving simultaneous effective dyeing and processing of the dye wastes remained. This study also contributes to energy saving and environmental protection. [ABSTRACT FROM AUTHOR]