Vacuum Impregnation Method Research Articles

In-Situ construction of Bulge-like microstructures in sugarcane-based superhydrophobic membranes for efficient separation of water-in-oil emulsions

The separation of oil/water pollution is of great importance to environmental protection. However, the development of superwetting materials for efficient separation of surfactant-stabilized oil/water emulsions still faces challenges. As agricultural waste, sugarcane straw contains many hydrophilic groups and multilayered pore structures, making it suitable for purifying oil/water emulsions by simple chemical modification treatments. Herein, sugarcane-based superhydrophobic membranes (SSMs) were prepared by a facile vacuum impregnation method in hexadecyltrimethoxysilane (HDTMS) solution. The unique bulge-like microstructures were constructed in the intrinsic pores of sugarcane, which significantly increased the roughness and resulted in superhydrophobicity with the water contact angle of 153.5°. More importantly, the bulge-like structure is easy to break the emulsion and thus SSMs offer excellent separation efficiency (> 99 %), suitable fluxes (368 L•m−2•h−1) and strong cycling stability for surfactant-stabilized water-in-oil emulsions. In addition, SSMs can separate oil/water mixtures and directly adsorb oil from water with adsorption rates exceeding 99 %. SSMs have good durability and anti-mold adherence properties, and they do not lose their unique wetting properties even in harsh environments. More importantly, SSMs can be degraded in soil at the end of their life cycle, avoiding secondary pollution for the environment. This simple, in-situ impregnation technique offers a novel way to create green, inexpensive and stable biomass membranes for effective water-in-oil emulsion separation, showing great promise for use in oily wastewater treatment.

Bacterial cellulose-based Janus energy storage phase change composite aerogel for efficient interfacial solar vapor generation

Interfacial solar evaporation systems based on Janus structures exhibit potential application prospects in terms of salt tolerance. However, intermittent and unstable light conditions limited the evaporation rate and water production performance of the evaporators. The introduction of energy storage phase change (ESPC) composite materials into the interface solar evaporators can effectively solve this problem. In this work, bacterial cellulose (BC) is selected as the matrix material, sodium alginate (SA) and multi-walled carbon nanotubes (MWCNTs) are added as functional fillers, and porous composite aerogels are prepared using direct freeze-drying. On this basis, Janus porous composite aerogel (J-BCS/CNT) with ESPC function is further constructed by depositing paraffin onto the upper layer of the aerogel through a unilateral vacuum impregnation method. The aerogel exhibits strong photothermal conversion capabilities and excellent thermal management properties. The addition of appropriate amount of MWCNTs enables it to obtain high latent heat storage and release functions, providing energy for operation in dark conditions. Under the solar irradiation of 1.5 kW m−2, J-BCS/CNT40% aerogel exhibits a high evaporation rate of 1.95 kg m−2h−1 in pure water and 0.67 kg m−2h−1 under dark conditions. The salt evaporation resistance test shows that the aerogel has excellent purification capabilities in high-concentration salt water (20 wt%) solutions. More importantly, the long-term energy storage-release tests of J-BCS/CNT in 3.5 wt% saline water indicate that the aerogel reveals excellent sustainability and latent heat release functions.

Preparation and Electrochemical Properties of High Specific Surface Carbon Aerogel/SnO2 Anode Materials for Li-Ion Batteries

Lithium-ion batteries have consistently been a focal point of research in the field of energy. Traditional graphite anodes no longer meet the increasing demands for energy density. SnO2, with its high theoretical capacity, environmental friendliness, and safety, has emerged as a promising anode material for the next generation. However, issues such as volumetric expansion and agglomeration during charge–discharge cycles hinder its practical application. Addressing these challenges, this paper combines the high capacity of SnO2 with conductive and highly porous carbon aerogels, comparing the performance differences between composite anodes prepared by vacuum impregnation and hydrothermal methods. The results show the following: (1) high specific surface area carbon aerogels are beneficial for enhancing performance; (2) vacuum impregnation yields relatively higher initial capacity and better cycle stability; and (3) hydrothermal synthesis results in a higher loading of SnO2.

Assessment of Changes in Selected Features of Pine and Birch Wood after Impregnation with Graphene Oxide.

In this work, pine and birch wood were modified by graphene oxide using a single vacuum impregnation method. The research results indicate that the impregnation of wood with graphene oxide increases the crystallinity of cellulose in both pine and birch wood, and the increase in crystallinity observed in the case of birch was more significant than in the case of pine. FT-IR analyses of pine samples impregnated with graphene oxide showed changes in intensity in the absorption bands of 400-600, 700-1500 cm-1, and 3200-3500 cm-1 and a peak separation of 1102 cm-1, which may indicate new C-O-C connections. In the case of birch, only some differences were noticed related to the vibrations of the OH group. The proposed modification also affects changes in the color of the wood surface, with earlywood containing more graphene oxide than latewood. Analysis of scanning electron microscope images revealed that graphene oxide adheres flat to the cell wall. Considering the differences in the anatomical structure of both wood species, the research showed a statistically significant difference in water absorption and retention of graphene oxide in wood cells. Graphene oxide does not block the flow of water in the wood, as evidenced by the absorbability of the working liquid at the level of 580-602 kg/m3, which corresponds to the value of pure water absorption by wood in the impregnation method using a single negative pressure. In this case, higher graphene oxide retention values were obtained for pine wood.

Study on the Synthesis of BTA@MSNs Nanocarriers

Abstract Mesoporous silica, characterized by its adjustable pore size, uniform distribution, stable structure, and non-toxicity, is widely used as an encapsulating material for corrosion inhibitors. This study initially established that, compared to the high-temperature calcination method, the removal of surfactants via the solvent extraction method yields mesoporous silica with uniform size and better dispersibility. Results from N2 adsorption-desorption tests indicated that the mesoporous silica prepared by the solvent extraction method had an average pore diameter of 2.41 nm, a volume of 0.42 cc/g, and a specific surface area of 69.73 m2/g. SEM and TEM analyses showed that the BTA@MSNs nanoparticles synthesized via a one-step method were approximately 100 nm in size, whereas those prepared by the vacuum loading method were about 50 nm, both exhibiting ordered mesoporous structures. UV-vis spectrophotometry results revealed that the loading capacity of BTA in the nanoparticles produced by the one-step synthesis method was significantly lower than that in the BTA@MSNs nanoparticles prepared via the vacuum impregnation method.

The Use of Beetroot Juice as an Impregnating Solution to Change Volatile Compounds, Physical Properties and Influence the Kinetics of the Celery Drying Process.

The effect of different methods of drying celery root enriched with beet juice by vacuum impregnation (VI) was studied. The process of convection drying, vacuum drying and freeze drying was carried out. Compared to dried indigenous celery, dry impregnated tissue was characterized by lower values of dry matter, L* and b* color parameters, as well as higher values of water activity, density and a* color parameter. In addition, VI reduced the drying time. Forty Volatile Organic Compounds (VOCs) were found in celery, while fifty-one VOCs were found in the profile of celery with beetroot juice. The innovative method of vacuum impregnation made it possible to produce a new type of product with changed properties and a variable VOCs profile. The best fit of the drying process kinetics was achieved by using the logistic model. Increasing the temperature during convection drying resulted in shorter drying time, increased values of dry matter, reduced the water activity value and altered VOCs.

Lauric acid based form-stable phase change material for effective electronic thermal management and energy storage application

Poor thermal management in electronic systems can lead to higher junction temperatures, accelerating failure mechanisms and reducing component lifespan. Integrating efficient thermal management techniques, such as heat sinks, is essential for ensuring durability and efficiency of electronic equipment. Heat sinks have limited capacity, but integrating phase change materials (PCMs) enhances cooling performance by harnessing latent heat storage. However, leakage and low thermal conductivity limit PCM's effectiveness. The current study developed highly conductive leakage-proof PCMs based composites using an ultrasonic and vacuum impregnation method with lauric acid as base, hexagonal boron nitride and expanded graphite as additives. The results demonstrate persistence of chemical integrity, as proven by FTIR analysis, and complete encapsulation of PCMs inside the expanded graphite structures. The form-stable composite PCMs exhibit a 450% increase in thermal conductivity and 77% photo-transmittance decrease compared to base PCMs. Despite a trade-off of a 11.5% reduction in latent heat, the composite demonstrates thermal stability up to 220 °C. Further, excellent chemical and thermal reliability is maintained even after 500 cycles. Furthermore, in thermal management for heat sink, the form stable composite efficiently dispersed heat, resulting in a 16 °C decrease in peak temperature compared to the heat sink without the composite.

The Thermal Energy Storage Characteristics of Oleic Acid Modified ZnO‐Decorated Polymer Matrix‐Supported Composite Phase Change Materials: Synthesis and Characterization

AbstractIn this study, modified nano zinc oxide (ZnO)‐reinforced polymer‐supported novel thermally enhanced form‐stable composite phase change materials (PCMs) are presented, which are prepared via water in oil emulsion polymerization and following impregnation process steps. First, ZnO nanoparticles are modified with oleic acid (OA) to obtain lipophilic structures for emulsion stability, which are designed to take a role as a heat transfer activator. To ensure the shape stabilization of n‐hexadecane used as organic PCM, polymeric support materials are synthesized in the presence of modified ZnO nanoparticles (ZnO@OA). The polymeric frameworks exhibit open porous morphology, and the thermal stability of the support matrix improves with the addition of ZnO nanofiller. In the second step, composite PCMs are prepared by incorporation of n‐hexadecane with the solvent‐assisted vacuum impregnation method into polymer composites. The 1.0% ZnO@OA incorporated composite PCM has the highest incorporation ratio and exhibits a thermal storage capability (η) of 100%. According to the T‐history and thermal conductivity tests, it is observed that the heat conduction rate is enhanced with the addition of ZnO@OA nanofiller. The conclusion is that the obtained ZnO@OA integrated composite PCMs have a remarkable potential for latent heat storage applications requiring low temperature in the range of 5–25 °C.

Thermal and electrical properties of palmitic acid/expanded graphite composite phase change materials for thermal energy storage

Expanded graphite (EG) based phase change material (PCM) has attracted significant concern in thermal management systems. In this paper, a series of composite PCMs composing of EG with different sizes (50, 80, and 100 mesh) as the substrate, and palmitic acid (PA) as the PCM, were prepared by vacuum impregnation method. The results shown that the size of EG particles effect the adsorption capacity of PA. The mass fraction of PA in PA/EG-50 reached 83.6% and the enthalpy of melting and solidification of PA/EG-50 are 160.13 J/g and 159.75 J/g, respectively. The thermal conductivity decreased slightly as the particle size of EG increased, and the thermal conductivity of PA/EG-100 is the highest of 4.86 W/(m·K). The TGA results show that all composite PCMs present good thermal stability below 200 °C. The electro-thermal conversion efficiency increased with the particle size of EG increasing, and the electro-thermal conversion efficiency of PA/EG-100 reached up to 91.39% under low-voltage conditions (1.9 V). These results throw light on the potential application of EG-based composite PCM, especially for the electro-thermal conversion.

Advancing tent thermoregulation: Integrating shape-stabilized PCM into fabric design

Shape-stabilized phase change materials (ss-PCM) were prepared by impregnating capric acid (CA) and palmitic acid (PA) eutectic mixtures into the pores of Expanded Perlite (EP) using vacuum impregnation method. The ss-PCM was coated on fabric's surface using polyurethane (PU) solution, with different PCM/PU ratio. The microstructure, chemical stability, thermal properties and thermal reliability of ss-PCM were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT–IR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Hydrophobicity performance was assessed by water contact angle (WCA). SEM images confirmed that CA–PA was successfully impregnated into the pores of EP. The results indicate that the latent heat of melting and freezing of the ss-PCM was 86.57 and 86.19 kJ/kg. The impregnated textile with the ss-PCM showed that the freezing enthalpies increased from 8.93 for Textile/PCM@5 up to 44.09 kJ/kg, for Textile/PCM@25 %. While Thermogravimetric analysis shows a good thermal stability of the composite textile/PCM. Mechanical properties revealed that the composite Textile/PCM@20 % present the higher tensile strength of 4.96 MPa compared to the other composite materials Furthermore, thermal cycling tests proved that the composite Textile/PCM@20 exhibits good long-term stability despite that both melting and freezing enthalpies were reduced by 7.4 and 14 %, respectively, after 100 cycles. These findings hold significant promise for applications in maintaining structures such as tents and buildings in thermal comfort range.

Dynamically frequency‐tunable and environmentally stable microwave absorbers

AbstractThe threat to information security from electromagnetic pollution has sparked widespread interest in the development of microwave absorption materials (MAMs). Although considerable progress has been made in high‐performance MAMs, little attention was paid to their absorption frequency regulation to respond to variable input frequencies and their stability and durability to cope with complex environments. Here, a highly compressible polyimide‐packaging carbon nanocoils/carbon foam (PI@CNCs/CF) fabricated by a facile vacuum impregnation method is reported to be used as a dynamically frequency‐tunable and environmentally stable microwave absorber. PI@CNCs/CF exhibits good structural stability and mechanical properties, which allows precise absorption frequency tuning by simply changing its compression ratio. For the first time, the tunable effective absorption bandwidth can cover the whole test frequency band (2−18 GHz) with the broadest effective absorption bandwidth of 10.8 GHz and the minimum reflection loss of −60.5 dB. Moreover, PI@CNCs/CF possesses excellent heat insulation, infrared stealth, self‐cleaning, flame retardant, and acid‐alkali corrosion resistance, which endows it high reliability even under various harsh environments and repeated compression testing. The frequency‐tunable mechanism is elucidated by combining experiment and simulation results, possibly guiding in designing dynamically frequency‐tunable MAMs with good environmental stability in the future.

Dual-modified catalytic core-shell structure biomass carbon cotton fiber extends broadband electromagnetic waves absorption applications

Using vacuum impregnation method, the biomass carbon cotton fiber material was modified with polymer-derived SiCN ceramics and different Ni sources to successfully prepare the composite material. The electromagnetic microwave absorption properties of the material in the range of 2–18 GHz and the catalytic effect of different nickel sources were studied. The material modified by nickel nitrate hexahydrate forms a carbon fiber coated structure, improves impedance matching, enriches heterostructures, and increases electromagnetic synergistic loss, effectively enhancing the effective absorption bandwidth (EAB) reaches 4.72 GHz, the minimum reflection loss (RLmin) is −47.79 dB, and the thickness is only 1.32 mm. The results of CST show that the radar cross section of CFPN-2 material is −36.86 dB m2, and it has obvious effect of optimizing impedance matching.

Efficient synthesis of benzyl-protected cyclic lysine on Pt/m-Al2O3 catalysts and its application in functional nylon-6 copolymers production

Functional nylon-6 polymers, particularly those with special properties such as antibacterial, flame retardant, and specialized thermal properties, have a wide range of applications. However, the efficient synthesis of these polymer monomers has long remained a challenge. Benzyl-protected cyclic lysine (BCL) is a potentially functional monomer, and this article proposes an efficient method for the synthesis of benzyl-protected cyclic lysine on a supported platinum catalyst. Compared to existing techniques, this approach offers higher synthesis efficiency and sustainability. Pt/m-Al2O3 (microspherical Al2O3) catalysts were prepared using a vacuum impregnation method and showed good activity and selectivity in the production of benzyl-protected cyclic lysine. The conversion rate of α-amino-ε-caprolactam (α-ACL) was 100%, and the selectivity of BCL was 96.0%. The Pt/m-Al2O3 catalyst maintained good stability over multiple reaction cycles. The reaction mechanism and thermodynamics of functionalized α-ACL were also investigated. The copolymer synthesized with the prepared BCL showed similar structure and thermal stability to pure nylon-6, indicating possible unique functional properties. This study provides a route for the synthesis of cyclic lysine protected with various groups and its potential applications in the field of polymer chemistry.

Gully-like CQDs/In2O3/TiO2 composite with broad spectral response and its enhanced photocatalytic performance

The morphology and structure of photocatalytic materials often have a great influence on their photocatalytic performance. The photocatalytic degradation and hydrogen production capacity can be enhanced by optimizing the morphology and properties of the catalysts. In this paper, on the basis of carbon quantum dots (CQDs) with up-conversion photoluminescence (UCPL) properties and polystyrene colloid microspheres (PS) as templates, a kind of gully-like CQDs/In2O3/TiO2 composites with wide spectral response was prepared by vacuum impregnation and microwave-assisted hydrothermal method. The results show that CQDs/In2O3/TiO2 composites with PS colloid microsphere as templates have a gully structure, which provides more active sites for photocatalytic reaction. The heterostructure formed among components optimizes the charge transfer path, significantly improving the separation and transfer efficiency of photogenerated electrons and holes. In the multi-mode photocatalytic experiments, CQDs/In2O3/TiO2 composites show excellent photocatalytic activity for methyl orange, of which photocatalytic activity is much higher than that of pure TiO2, displaying a certain degree of degradation for the different kinds of dyes. In addition, the hydrogen evolution capacity of CQDs/In2O3/TiO2 composites is 1149.3 μmol/g for 8 h, which is 7 times of that of monomer TiO2. The results of the capture experiments show that the possible photocatalytic mechanism of CQDs/In2O3/TiO2 composites is more likely to be the result of a synergy between the traditional band theory and the "Z-scheme".

Novel synthesis of FeF3·0.33H2O@hollow acetylene black nanosphere and its long-life electrochemical properties as a cathode for lithium-ion batteries

Iron (III) fluoride (FeF3), characterized by high voltage and high specific capacity and emerges as a promising candidate for the forthcoming generation of cathode materials in lithium-ion batteries. This study employs a novel methodology by introducing Fe3+ sources into hollow acetylene black particles through a vacuum impregnation method. This innovative approach results in the synthesis of a composite material comprising FeF3∙0.33H2O encapsulated within hollow acetylene black nanospheres, denoted as the FeF3∙0.33H2O @hollow acetylene black nanosphere composite material (FF@HCN). The composite exhibits a shell composed of highly graphitized carbon and a core containing FeF3∙0.33H2O particles in the range of 10–20 nm. The proportion of active materials is 75.56 %. The acetylene black has chain-like structure and high specific surface area, significantly enhances the material's conductivity, contributing 74.4 % to the pseudocapacitance at a scan rate of 1 mV s−1. The cavity graphite shell plays a crucial role in restricting the expansion and pulverization decay of FeF3∙0.33H2O nanoparticles, thereby markedly improving the cycle stability. The initial capacity of the FF@HCN composite is 224.4 mAh g−1, and after 1000 cycles at 0.1 C, it maintains a capacity of 162.3 mAh g−1, resulting in a capacity retention rate of 72.3 % and decay per cycle of 0.027 %.

Development of a novel composite phase change material based on paints and brick for energy storage applications in agricultural greenhouses

This study addresses challenges associated with supercooling, phase separation, and inadequate thermal properties in Na2SO4·10H2O (SSD) by expanding the application of inorganic hydrate salt phase change materials within agricultural greenhouses. A novel composite phase change material, Na2SO4·10H2O-Al2O3 (NAPCM), was successfully synthesized using the vacuum impregnation method. NAPCM was strategically incorporated into paints and hollow bricks, leading to the creation of innovative phase change paint and phase change bricks designed for efficient thermal energy storage in agricultural greenhouses. The investigation revealed the homogeneous dispersion of porous Al2O3 particles in SSD, effectively preventing phase separation in NAPCM and ensuring its durable shape stability. The interaction between SSD and porous Al2O3 remained purely physical, with porous Al2O3 acting as an effective modifier to adjust various thermal properties of SSD. Optimal mass ratio determination for the combination of paint and NAPCM particles resulted in a 9:1 ratio, ensuring the uniform distribution of NAPCM particles within the paint matrix. This achieved a particle size averaging 290.93 μm with no discernible leakage features. The phase change paint exhibited an impressive solid content of 56.62 %, demonstrating exceptional resistance to water, alkali, salt, and abrasion. In thermal plate testing, the phase change paint significantly decelerated the heating rate. Infrared thermal imaging observations depicted circular areas with temperatures notably lower than their surroundings, indicating NAPCM's ability to impede heat absorption during the heating process, thereby reducing the rate of temperature change. The phase change paint also exhibited a slower cooling rate in the cooling test. Simultaneously, phase change bricks demonstrated superior thermal insulation compared to ordinary bricks. Throughout the heat storage phase, the temperature of the phase change greenhouse wall was lower than that of an ordinary greenhouse, while in the heat release phase, it was higher. The phase change greenhouse, relative to its ordinary counterpart, demonstrated superior insulation effects, creating a warm environment conducive to plant growth. This advancement enhances the energy storage performance of agricultural greenhouses, providing a novel solution for improving energy efficiency and environmental sustainability.

Experimental investigation on the stability and heat transfer enhancement of phase change materials composited with nanoparticles and metal foams

Conventional phase change materials (PCMs) possess the challenge of low thermal conductivity, which hinders the energy exchange rate and storage efficiency. PCMs composited nanoparticles and metal foams have been a proven solution to enhance the thermal characteristics of PCMs. In this work, three enhanced PCM composites including nanoparticle/paraffin, metal-foam/paraffin and nanoparticle/metal-foam/paraffin were prepared using fusion blending and vacuum impregnation method. The effects of different nanoparticles with different mass fractions on the stability and heat storage and release characteristics of nanoparticle/paraffin were investigated. Compared with paraffin, the melting time and solidification time of nano-metal/paraffin are reduced by a maximum of 30.18 % and 43.15 %, respectively. In addition, the effect of pore density of metal foam on natural convective heat transfer process was evaluated. The results showed that the stability in descending order is as follows: nano‑aluminum, nano‑copper and nano‑silver. The optimal mass fraction of nanoparticles with good stability was 1.5 wt% (copper), 1.0 wt% (silver), 1.5 wt% (aluminum), respectively. The metal foam makes the internal temperature distribution of PCMs more uniform in the heat transfer process, while inhibiting the convective heat transfer process. With the increase of pore density, the effect on natural convection heat transfer process rises. When the PPI (pores per linear inch) of foamed metal is greater than 40, the natural convection process can be inhibited, obviously. The foam metal has a more significant effect on the heat transfer performance of nanoparticle/metal-foam/paraffin than that of the nanoparticles. The economic benefits of nanoparticle/paraffin, metal-foam/paraffin and nanoparticle and metal foam composite phase change materials are progressively decrease, with MFP being suitable for applications with high economic budgets.

Shape-stable phase change materials based on carboxymethyl chitosan/boron nitride nanosheets high-strength aerogel

The application of phase change materials (PCMs) in energy storage and temperature control systems holds significant promise for enhancing energy efficiency and environmental sustainability. Herein, the development of a boron nitride nano-aerogel-supported PCM, reinforced by carboxymethyl chitosan (CMCS) and oxidized corn starch (DCS) cross-linking was reported. This approach involved the utilization of polydopamine-modified boron nitride nanosheets (PDA@BNNS) for the fabrication of a thermally conductive skeleton, while carboxymethyl chitosan (CMCS) and oxidized corn starch (DCS) were utilized as reinforcing material and cross-linking agent, respectively. The skeleton was prepared via a sol-gel method and freeze-drying technique, while polyethylene glycol (PEG) was subsequently encapsulated using a vacuum impregnation method. Notably, the prepared skeleton exhibits a compressive stress of 12.18 MPa at 80 % strain, much higher than other boron nitride nanosheets aerogels reported in literature. The cross-linked boron nitride skeleton enhances the thermal conductivity of the composites by 137.4 % compared to pure PEG. Furthermore, due to the highly porous structure of the skeleton, the PEG mass fraction reaches 96.0 wt%, resulting in a phase change enthalpy of 181.5 J/g. The results suggest that this composite material is a promising PCM candidate for thermal energy storage applications.

Regulating lattice tensile strain of Ru-Co bimetallic nanoparticles on carbonized wood for boosting its hydrogen evolution reaction

The development of high-performance catalysts for hydrogen production originating from water electrolysis at the cathode is very crucial, but still a challenge. Here, trace Ru-doped Co bimetallic nanoparticles (named RuxCoy/CW-z, x/y and z represent the molar ratio and total molar content of metals) were in situ decorated on carbonized wood by the vacuum impregnation and high-temperature annealing method. Ru1Co10/CW-2 demonstrates good hydrogen evolution reaction (HER) intrinsic activity with the overpotential of −42 mV (at −10 mA/cm−2) and Tafel slope of 75 mV dec−1 in a 1.0 M KOH, indicating its favorable HER reaction kinetics, and Ru1Co10/CW-2 exhibits good stability for 100 h (at −50 mA/cm−2). The good performances of Ru1Co10/CW-2 can be ascribed to the adjustable lattice tensile strain and electronic interactions, while the porous carbonized wood promotes electron transfer, electrolyte transport and gas escape. This work combines the advantages of lattice tensile strain with self-supported porous carbonized wood for HER in alkaline solution, which provides a valuable reference for synthesizing carbonized wood electrode materials with very low Ru content.

Efficient self-healing coatings embedded with polydopamine modified BTA@DMSNs for corrosion protection

Dendritic mesoporous silica nanoparticles (DMSNs) were successfully prepared with a specific surface area of 608.8 m2/g and an average pore size of 24.2 nm, providing a strong support for the successful loading of benzotriazole (BTA). BTA@DMSNs were prepared using the vacuum impregnation method. A pH-responsive polydopamine (PDA) outer layer was self-polymerized on the surface to obtain BTA@DMSNs/PDA microcapsules. The pH-responsive BTA@DMSNs/PDA microcapsules were prepared with the high BTA content of 20.1 wt%. Mean diameter of microcapsules was 210 ± 25 nm. The release profiles under different pH conditions confirmed the pH-responsive behavior of BTA/DMSNs@PDA microcapsules. The coatings with 1 wt% BTA@DMSNs/PDA microcapsules exhibited optimal anti-corrosion and self-healing performance. The |Z|0.01Hz of EP/1 wt%/BTA/DMSNs@PDA remained the highest among all coatings even after being immersed in 3.5 wt% NaCl solution for 50 d through the EIS measurement. It only had a slight change from 3.8 × 1010 Ω·cm2 to 6.8 × 109 Ω·cm2, which was 80 times that of the EP for 50 d, indicating that the coatings had excellent long-term anti-corrosion effect and good shielding performance. Furthermore, the |Z|0.01Hz of the artificially cross-scratched coatings that were immersed for 30 d remained at 6.9 × 104 Ω·cm2, which was one order of magnitude higher than EP (6.3 × 103 Ω·cm2), and the surface of coatings remained intact, showing that the scratched coatings had outstanding self-healing performance.