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Propane-1,2,3-triol-loaded polysulfone (PSF) microcapsules were prepared by the solvent evaporation method. The particle size of the microcapsules is about 140 μm. The shell wall thickness is about 17 μm approximately. The microcapsules have high thermal stability and antiwear performance. The self-healing coating was prepared by adding the prepared capsule into the epoxy resin coating. After electrochemical and corrosion immersion experiments, the resistance modulus of the coating added to the microcapsules was higher than the others in a 3.5 wt % NaCl corrosion solution, and it had the lowest corrosion current density, so the self-healing microcapsule coatings showed excellent healing ability and corrosion inhibition function for microcracks. This was attributed to the formation of a hydrophobic film after propane-1,2,3-triol was released from the damaged microcapsules.

The design of a high-performance, durable and low-cost catalyst for direct ethanol fuel cells (DEFCs) applications is an eternal pursuit for researchers in the materials field. In this work, a kind of novel platinum-tungsten carbide (Pt-WC)/multi-walled carbon nanotubes (MWCNTs) electrocatalyst with different WC loadingsis prepared by self-assembly technology for ethanol oxidation reaction (EOR). The electrochemical performance and stability of Pt-WC/MWCNTs electrocatalysts toward EOR are investigated by cyclic voltammetry and chronoamperometry. The mass activity of Pt-WC0.15/MWCNTs electrocatalyst for EOR is 581.94 mA mg-1Pt, which is 1.33 times higher than that of commercial Pt/C (ETEK). The significant enhancement can be attributed to the more exposed active sites and the synergistic effect between Pt and WC. The Pt-WCx/MWCNTs are a kind of excellent and effective electrocatalyst for EOR, which has a broad application prospect in fuel cells.

The tribocorrosion performance of low-temperature steels is vital for use in hostile environments. This study aims to investigate the tribocorrosion behavior of FH36 low-temperature steel with two distinct microstructures of tempered martensite (TM) and tempered sorbite (TS), respectively. Also, the coefficient of friction, surface morphologies, electrochemical properties, and corrosion features of the two steels were investigated. The results showed that the TM and TS steel exhibited outstanding impact toughness values of 239 and 306 J at −60°C, respectively. The friction coefficient and the electrochemical impedance in the TM steel were lower than those of the TS steel, while the scratch was deeper and narrower in the TM steel. Both the microstructure and the electrochemical corrosion affect the wear resistance of the low-temperature steels during the tribocorrosion process. The friction can accelerate the adsorption of Cl− ions that enrich the pits near the scratches, and the pitting of the TM steel was severe.

A simple wet chemical method was used to prepare two-dimensional transition metal carbides (MXene); PDA-MXene was prepared by alkalization of p-phenylenediamine (PDA) on MXene. And further, Pd metal nanoparticles (NPs) were conveniently loaded on the surface to catalyze the dehydrogenation of formic acid. The as-prepared Pd/PDA-MXene catalyst for the formic acid dehydrogenation was characterized by XRD, IR, TEM, and XPS. Pd-NPs with a size of about 4 nm were formed upon the PDA-MXene support surface and were well dispersed. The Pd/PDA-MXene exhibited good catalytic activity in the formic acid decomposition process without any additives, and the turnover frequency value at 50 °C was 924.4 h−1, which is comparable to most of the reported noble metal catalysts under similar conditions. It is worth mentioning that the prepared catalyst maintained good catalytic activity in five consecutive catalytic cycles of the formic acid dehydrogenation experiment.

The wear and corrosion resistance of Ni-based niobium carbide (NbC) coatings were investigated via scanning electron microscopy, energy dispersive spectrometry, particle size analysis, X-ray diffraction, electrochemical polarization, electrochemicl impedance spectroscopy, digital microhardness testing and wear testing. The results showed that the substrate was mainly composed of a γ-Cr (Fe) solid solution, and the composite coating was composed of FeNi, NbC, and Ni. In addition, the hardness of the coating increased gradually with increasing NbC content. The optimal corrosion resistance and wear resistance of the coating were realized at an NbC content of 20%.

Metal corrosion often results in incalculable economic loss and significant safety hazards. Although numerous traditional methods have been used to mitigate the issue, such as coating and corrosion inhibitors, they are environmentally unfriendly and difficult to maintain. Therefore, in this study, an environmental approach was taken to protect steels from corrosion in a multi-species bacterial environment via synergistic biomineralization. The marine bacterium Pseudoalteromonas lipolytica mixed with Bacillus subtilis or Pseudomonas aeruginosa strains offered extraordinary corrosion protection for steel. The surface characterization and electrochemical tests showed that the biomineralized film generated by the mixed bacteria was more compact and protective than that induced by a single bacterium. Herein, we found that the synergistic mechanisms were rather different for the different bacterial groups. For Pseudoalteromonas lipolytica and Bacillus subtilis group, the related mechanisms were due to the increase of pH in the medium, secretion of carbonic anhydrase. As for Pseudoalteromonas lipolytica and Pseudomonas aeruginosa group, the synergistic mechanism was attributed to the inhibiting corrosive bacteria in biofilm by the growth advantage of Pseudoalteromonas lipolytica. Therefore, this study may introduce a new perspective for future use of biomineralization in a real marine environment.

Pyrite (FeS

Fe-based coatings reinforced by spherical tungsten carbide were deposited on 304 stainless steel using plasma transferred arc (PTA) technology. The composition and phase microstructure of the coatings were evaluated using scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The corrosion behaviors of the coatings in 0.5 mol/L HCl solution were studied using polarization curve and electrochemical impedance spectroscopy (EIS) measurements. The experimental results shows that the tungsten carbide improves the corrosion resistance of the Fe-based alloy coating, but increase in the mass fraction of tungsten carbide leads to increasing amount of defects of holes and cracks, which results in an adverse effect on the corrosion resistance. The defects are mainly present on the tungsten carbide but also extend to the Fe-based matrix. The tungsten carbide, acting as a cathode, and binding material of Fe-based alloy, acting as an anode, create a galvanic corrosion cell. The binding material is preferentially corroded and causes the degradation of the coating.

Interfacial solar vapor generation has recently drawn much attention because of its high solar-to-vapor generation efficiency. Here we introduce the basic experimental procedures and analysis for u...

Microwave absorption has been very critical for many civil and military applications. In this study, we report for the first time the porous plasmonic Cu9S5 nanonets possessing an excellent microwave absorption performance with a large reflection loss (RL) of −55.03 dB (over 99.999% absorption efficiency) and a maximal effective bandwidth of 4.15 GHz (RL ≤ −10 dB). The impressive microwave absorption performance is attributed to the large pore volume, multireflection of electromagnetic waves, and increased microwave absorption sites on the unique porous structure and the impressive plasmonic properties of Cu9S5 nanonets. The results have demonstrated potentially promising prospects of plasmonic Cu9S5 nanonets as a new material candidate for microwave absorption.

Fe-based coatings reinforced by spherical WC particles were produced on the 304 stainless steel by plasma transferred arc (PTA) to enhance the surface wear properties. Three different Fe/WC composite powder mixtures containing 0wt%, 30wt%, and 60wt% of WC were investigated. The microstructure and phase composition of the Fe/WC composite PTA coatings were evaluated systemically by using scanning electron microscope (SEM) and X-ray diffraction (XRD). The wear properties of the three fabricated PTA coatings were investigated on a BRUKER UMT TriboLab. The morphologies of the worn tracks and wear debris were characterized by using SEM and 3D non-contract profiler. The experimental results reveal that the microhardness on the cross-section and the wear resistance of the fabricated coatings increase dramatically with the increasing adding WC contents. The coating containing 60wt% of WC possesses excellent wear resistance validated by the lower coefficients of friction (COF), narrower and shallower wear tracks and smaller wear rate. In the pure Fe-based coating, the main wear mechanism is the combination of adhesion and oxidative wear. Adhesive and two-body abrasive wear are predominated in the coating containing 30wt% of WC, whereas threebody abrasion wear mechanism is predominated in the coating containing 60wt% of WC.

The Bacillus subtilis can induce biomineralized film formation on the surface of steel, which is associated with the positive effects on corrosion. However, the addition of 0.4 wt% Cu to the steel changes the film composition and structures significantly. The biological analyses reveal the mechanism through which Cu influences the metabolism of Bacillus subtilis and carbonate precipitation. The latter plays an important role in protecting corrosion. Furthermore, corrosion pits are larger and more for Cu-steel compared with control steel (free of Cu). This study introduces a new insight for designing an anticorrosion steel in the presence of biomineralized film.

Commercial vehicle industry worldwide is facing challenges from environmental pressures, stringent limits of CO2 emission, governmental regulations as well as ever-increased customer demands. This paper analyzes the above-mentioned challenges, especially in China, including the potential improvement to increase the brake thermal efficiency (BTE), with five levels of BTE proposed, ranging from current 45 to 60% in future, corresponding to China fuel consumption regulation (CFCR) in different phases. The authors also proposed the technology roadmaps to meet the upcoming CFCR3 and CFCR4; finally, the authors draw the conclusions to conform with ever-stringent regulation in China.

A Ni-based alloy coating with 30 wt.% spherical tungsten carbide particles was prepared through plasma transferred arc welding on 42CrMo steel. The composition and microstructure of the coating were examined through X-ray diffraction and scanning electron microscopy with energy-dispersive spectrometry. The corrosion behaviors of the coating compared to the Ni coating without tungsten carbide particles and to the bare substrate in a 0.5 mol/L HCl solution were presented through polarization curves, electrochemical impedance spectroscopy (EIS) measurements and long-term immersion tests. The results demonstrated that the composite coating microstructure comprised Ni matrix, Ni-rich phase, tungsten carbide particles, W-rich phase and Cr-rich phase. The polarization curves and EIS measurements presented that a passivation film, which mainly included Ni, Cr, Fe and W oxides, was formed in the composite coating that protected the substrate from corrosion by HCl solution. In the immersion tests, a micro-galvanic reaction at the new-formed phases and Ni matrix interface caused severe pit corrosion and Ni matrix consumption. The debonding of Ni-rich and W-rich phases could be observed with the immersion time extension. The tungsten carbide particles and Cr-rich phase were still attached on the surface for up to 30 days.

In this study, Cu-Ni-Si alloy was subjected to corrosion resistance tests under simulated high-temperature, high-pressure H2S and Cl− environments. The corrosion rates, electrochemical performance, surface morphologies, and chemical compositions of the Cu-Ni-Si alloy after corrosion were analyzed by the mass loss method, electrochemical impedance spectroscopy, scanning electron microscopy, energy-dispersive x-ray spectrometry, and x-ray diffraction. The results showed that, at the initial stage of corrosion, because of the loose corrosion product layer initially formed on the surface, a high corrosion rate was observed for the Cu-Ni-Si alloy under high-temperature, high-pressure environments. With the progress of corrosion, the corrosion rate gradually decreased and reached a steady state. Because at the later stage, a passive film was formed on the alloy surface, further inhibiting the corrosion of the alloy and improved its corrosion resistance. The Cu-Ni-Si alloy exhibited good corrosion resistance under high-temperature, high-pressure H2S and Cl− environments.

In this work, the adsorption behaviors of CO and CH3OH at low coverage on Pt monolayer (ML) on WC (0 0 0 1) and Pt (1 1 1) surfaces are studied through the density functional theory. The number of active sites, surface structure, composition and atomic arrangement of electrocatalysts are established to investigate how they affect the Pt utilization and catalytic performances. The results show that the d-band center of PtML/WC (0 0 0 1) surface is downshifted to −3.11 eV, which decreases the adsorption energies of adsorbates on the surface. For CO and CH3OH molecules, the adsorption energies on PtML/WC (0 0 0 1) surface are weaker than Pt (1 1 1) surface. Theoretically, the Pt/WC should have higher tolerance for CO poisoning than the Pt/C catalyst. This work provides a theoretical understanding for designing Pt/WC electrocatalysts, which is beneficial to advance the development of efficient catalysts for direct methanol fuel cells.

The use of biomineralized films to protect steel surfaces is limited by the strict selection of bacteria capable of mineralization. Inspired by the different effects of the Pseudoalteromonas lipolytica mutants on steel corrosion, we found that bacterial cellulose (BC) plays an important role in corrosion protection. The endogenous cellulose was beneficial to the formation of uniform biofilms, while exogenous BC provided a stable anticorrosion activity through biomineralization. Moreover, the addition of BC extracted from the P. lipolytica ∆17125 strain into a culture medium with corrosive P. lipolytica ∆bcs or Vibrio natriegens resulted in systems with significant corrosion-inhibition abilities.

Steel corrosion is a global problem in marine engineering. Numerous inhibitory treatments have been applied to mitigate the degradation of metallic materials; however, they typically have a high cost and are not environmental friendly. Here, we present a novel and "green" approach for the protection of steel by a marine bacterium Pseudoalteromonas lipolytica. This approach protects steel from corrosion in seawater via the formation of a biofilm followed by the formation of an organic-inorganic hybrid film. The hybrid film is composed of multiple layers of calcite and bacterial extracellular polymeric substances, exhibiting high and stable barrier protection efficiency and further providing an in situ self-healing activity. The process involving the key transition from biofilm to biomineralized film is essential for its lasting anticorrosion activity, which overcomes the instability of biofilm protection on corrosion. Therefore, this study introduces a new perspective and an option for anticorrosion control in marine environments.

The ever-dwindling freshwater sources and ever-increasing need for freshwater resources are regarded as two important concerns for current society. Solar vapor generation has proven to be an effective and reliable solar-driven technology to overcome these concerns. However, it is a big challenge to prepare low-cost and high-efficiency solar absorber for solar vapor generation. Herein, we report a novel structurally integrated solar absorber composed of CuS nanoflowers and semipermeable collodion membrane (SCM). Three-dimensional (3D) covellite CuS nanoflowers composed of nanosheets have been synthesized with a facile hydrothermal route and their morphology and structure are investigated with various analytical techniques. High solar vapor generation efficiencies of 68.6% and 81.2% were achieved with CuS/SCM under 1 and 4 sun irradiation, respectively, much higher than that of the CuS nanofluid. A stable solar vapor generation performance has been demonstrated over 20 cycles. These results display a promising potential of CuS/SCM as a solar-absorber for efficient solar vapor generation.

Water evaporation, a promising and environmentally friendly technology driven by local hot spots on the water-air interface, is an efficient way to utilize solar energy. Herein, we present a novel laminar solar absorber consisting of graphite powder (GP) and a semipermeable collodion membrane (SCM) as an integrated structural system for highly efficient water evaporation. The GP/SCM composite can efficiently convert the absorbed solar energy to heat energy, e.g., the 8 mg-GP/SCM (i.e., the GP/SCM with 8 mg GP added) enables water evaporation with high efficiency of 56.8% under 1.5 kW/m2 irradiation and 65.8% under 3 kW/m2 irradiation, respectively. Cycling tests verify that the GP/SCM could retain stable water evaporation performance over 20 cycles under the same conditions. Contrast experiments show that the other carbon-containing solar-absorbers, such as acetylene black (AB) and graphene nanoplates (GNPs) in SCM, display relatively low evaporation efficiency of 41.4% and 36.7%, respectively, under the simulated solar irradiation with a light density of 1.5 kW/m2. The laminar GP/SCM composite obtained in our work is low-cost, easy-to-prepare, recyclable, and highly efficient in its photothermal performance, so that it distinctly contributes to water evaporation.

The wear and corrosion resistance of Fe72.2Cr16.8Ni7.3Mo1.6Mn0.7C0.2Si1.2 and Fe77.3Cr15.8Ni3.9Mo1.1Mn0.5C0.2Si1.2 coatings laser-cladded on AISI 4130 steel were studied. The coatings possess excellent wear and corrosion resistance despite the absence of expensive yttrium, tungsten, and cobalt and very little molybdenum. The microstructure mainly consists of dendrites and eutectic phases, such as duplex (γ+α)-Fe and the Fe–Cr (Ni) solid solution, confirmed via energy dispersive spectrometry and X-ray diffraction. The cladded Fe-based coatings have lower coefficients of friction, and narrower and shallower wear tracks than the substrate without the cladding, and the main wear mechanism is mild abrasive wear. Electrochemical test results suggest that the soft Fe72.2Cr16.8Ni7.3Mo1.6Mn0.7C0.2Si1.2 coating with high Cr and Ni concentrations has high passivation resistance, low corrosion current, and positive corrosion potential, providing a better protective barrier layer to the AISI 4130 steel against corrosion.

Electrochromic (EC) energy storage devices that could realize the multifunctional integration of energy storage and electrochromism have gained much recent attention. Herein, an EC battery based on the hybrid film of W18O49 and polyaniline (PANI) is developed and assembled, which integrates energy storage and EC functions in one device. The W18O49/PANI-EC battery delivers a discharging capacity of 52.96 mA h g−1, which is about two times higher than that of the W18O49-EC battery. Sunlight irradiation could greatly promote the oxidation reactions of both W18O49 and PANI during the charging process of the W18O49/PANI-EC battery, thus effectively accelerating the charging rate. This work provides a green, convenient, environmentally friendly, and cost-free charging strategy for the EC energy systems and could further advance the development of the multifunctional EC devices based on the organic/inorganic composites.

The development of flexible electronics has an important impact on areas ranging from stretchable sensors and bendable batteries to wearable devices. Here, a facile, effective, low-cost, and convenient strategy has been employed to fabricate flexible strain sensor with hexagonal ZnO nanorods (NRs) and carbon black as sensing elements, polydimethylsiloxane (PDMS) as matrix, and latex film as substrate. The as-assembled strain sensors hold the merits of high flexibility, high sensitivity, large workable strain range, good linearity, and ideal stability. Compared to the carbon black-based sensor, the ZnO/carbon black-based sensor exhibits highly enhanced sensitivity under tensile stress. The ZnO/carbon black-based sensor also demonstrates the capability of detecting and differentiating various degrees of human motions such as wrist rotation, knee flexion, and finger tapping, as well as the competence of monitoring human activity like pulse beat. The present method for the assembly of the ZnO-based flexible strain sensor opens up a new route for the fabrication of other wearable flexible electronics.

The increasing energy and environmental concerns have spurred enormous research interest towards developing various renewable energy and sustainable environmental solutions. Photothermal conversion for interfacial solar vapor generation is a promising, green energy technology and efficient route for desalination and purification of seawater, i.e. for those parts where freshwater shortage is a severe concern and clean energy is not available. Eco-friendly, highly efficient and low-cost interfacial evaporators are highly desirable for the practical and widespread application of this technology. In this work, we have demonstrated a novel interfacial evaporator employing Cu9S5 nanonets with heterogeneous hexagonal holes as the photothermal conversion material and a microporous poly(vinylidene fluoride) membrane (PVDFM) as the supporting material. The Cu9S5/PVDFM evaporator displays a broadband (from 250 to 2000 nm) and large (∼91.7%) solar absorptance. The porous structures of Cu9S5 nanonets and PVDFM facilitate the water transportation, and the large optical absorption of Cu9S5/PVDFM converts most of the solar energy to thermal energy, producing water vapor with high efficiency. The Cu9S5/PVDFM evaporator exhibits solar vapor generation efficiencies of 80.2 ± 0.6% and 91.5 ± 1.1% under one-sun and four-sun irradiation, respectively, making it among the best copper sulphide-based solar evaporators reported so far. This Cu9S5/PVDFM evaporator is reusable, flexible, highly efficient, easy to prepare, easy to scale up, and controllable for tailoring, showing a promising future for interfacial solar vapor generation.

The effect of solution pH, Cl− concentration and temperature on the electrochemical corrosion behavior of PH13-8Mo steel in acidic solution was investigated by using the electrochemical tests, scanning electron microscopy and X-ray photoelectron spectroscopy. The PH13-8Mo martensitic precipitation hardened stainless steel is in the passivity state when the pH value is above 3.0, below which the anodic polarization curves of the steel are actively dissolved. The corrosion current density gradually decreases with increasing the solution pH and decreasing Cl− concentration and solution temperature. Pits are initiated on the sample surface in the presence of the Cl− and gradually developed into uniform corrosion with increasing the Cl− concentrations. Moreover, the corrosion is more serious with an increase in solution temperature.

Despite the exotic electromagnetic properties have been demonstrated in metamaterials to date, how to effectively adjust negative electromagnetic parameters remains a challenge. Tunable negative permittivity is essential for the metamaterials to satisfy a variety of practical applications, such as capacitor, microwave absorbing and shielding. Here, we fabricated a random metamaterial, carbon/silicon nitride (C/Si3N4) composite, using a feasible impregnation-pyrolysis method. The microstructure and dielectric property of the composites with different heat treatment temperatures (HTTs) and carbon contents were investigated. The amorphous carbon membrane adhered on the rod-like Si3N4 grains. The negative permittivity behavior combined with inductive character was obtained in the composites, which was attributed to the low frequency plasmonic state generated from the formative conducting carbon networks. The magnitude of negative permittivity is demonstrated to be successfully adjusted by controlling the HTT and carbon content. The result is in good agreement with the analysis of Drude model. Interestingly, a weakly negative permittivity behavior was observed in the measured frequency, showing small negative values of permittivity between −50 and −10, which was ascribed to a moderate carrier concentration provided by the carbon networks. This work provides an effective way to achieve the tunable and weakly negative permittivity in random metamaterials.