Solution Immersion Method Research Articles

Structural and Optical Properties of Graphene Oxide:Zinc Oxide on Different Types of Substrates

The structural and optical properties of ZnO-based nanostructure exhibit substrate-dependent variations. A comprehensive understanding of how different substrates influence the crystalline structure, absorbance and surface morphology of the deposited films remains a great challenge. This study was done to investigate the structural and optical properties of zinc oxide (ZnO) that alter with graphene oxide (GO) deposited on various substrates; glass, silicon, indium tin oxide (ITO) and polyethylene terephthalate (PET) by solution immersion method. The structural properties were studied using X-ray diffraction (XRD) and Fourier-transform infrared (FTIR). The optical properties of samples were determined using ultraviolet-visible (UV-VIS) spectroscopy and Raman spectroscopy. The XRD result revealed that all GO/ZnO samples have polycrystalline structures while FTIR showed the presence of C-O, C=O and C-H compounds on all substrates. The highest absorbance of 3.40 was shown by the GO/ZnO sample which was grown on a glass substrate while the lowest absorbance of 1.50 was exhibited by the sample that was grown on PET substrate. Based on the Raman spectrum all samples showed variety in phonon energy when ZnO was grown on different substrates.

CuS and polydopamine-modified polyvinyl alcohol foam for steady interfacial solar desalination of high saltwater

Interfacial solar desalination generation (ISDG) presents a promising solution for obtaining freshwater from seawater. However, developing solar evaporators with robust salt resistance using simple methods to ensure consistent desalination performance remains a major challenge. In this study, we engineered a solar evaporator (CuS-PDA-PVAF) by modifying polyvinyl alcohol foam (PVAF) with polydopamine (PDA) and CuS using a straightforward solution immersion method. The incorporation of PDA and CuS enhances the sunlight absorption capability of PVAF to approximately 98 %, resulting in an evaporation rate of 1.44 kg m–2 h–1 under 1-solar intensity. The CuS-PDA-PVAF solar evaporator leverages the macroporous structure and excellent hydrophilicity, enabling it to withstand 15 wt% saltwater while maintaining a steady evaporation rate of about 1.17 kg m–2 h–1. Outdoor tests confirm that a 1 m2 CuS-PDA-PVAF can generate approximately 5.6 kg of freshwater daily. This solar evaporator, designed simply and resistant to salt, possesses substantial potential for alleviating freshwater scarcity.

Structural properties of LATP ceramic pellets sintered at 900 °C and modified by a novel solution-immersion densification process

The high temperature sintered ceramic pellets of solid electrolyte Li1.3Al0.3Ti1.7(PO4)3 (LATP), obtained in the absence of any sintering aids, should contain a large amount of interparticle gaps, which is one of the main bottlenecks in developing LATP-based all-solid-state Li-metal batteries. In this study, a facile solution (LiCl in ethanol) immersion method is adopted to soak the already 900℃-sintered LATP ceramic pellets, and the resulting series of LATP-xLiCl (x denotes the weight fraction of LiCl, 0.0 ≤ x ≤ 3.7) are assayed to address the high-performance mechanism of lithium-graphite (Li-C) symmetric cells. At the optimal x value of 2.3, the grain-boundary resistance of the ceramic pellet can be significantly reduced from 1772 to 28 Ω·cm² at room temperature, which endows the Li-C symmetrical cells of LATP-2.3LiCl with a high critical current density of 3.00 mA cm² at 60°C. Especially, the enhanced ionic conductivity of LATP-2.3LiCl (4.7×10−4 S cm−1, at 20℃; 1.1×10−3 S cm−1, at 60℃) indicates an effective strategy of utilizing capillary force to densify LATP-based ceramic pellets for potential application purposes.

Polystyrene Waste-ZnO nanocomposite film for energy harvesting via hydrophobic triboelectric nanogenerator: Transforming waste into energy

This research aimed to generate electricity from polystyrene waste materials combined with zinc oxide (ZnO) nanomaterials. Developing alternative polystyrene waste materials for generating electricity in triboelectric nanogenerator (TENG) could be beneficial in a circular economy and sustainable development. With the motivation to reduce environmental pollution by using polystyrene waste, a recycled polystyrene-ZnO nanocomposite film (rPS-ZnO NF) was synthesized and served as a triboelectric material for energy harvesting applications. ZnO nanopowder was produced by a low-temperature solution immersion method in conjunction with a simple film-casting method to prepare the rPS-ZnO NF. The effects of varying amounts of toluene as a solvent medium and the immersion time in stearic acid (SA) solution treatment on the structural properties, wettability behavior, surface morphology, chemical bonding properties, surface characteristics, and TENG performance were investigated. In this work, rPS film, rPS-ZnO NF, and SA-treated rPS-ZnO NF were paired with Kapton film as the opposite triboelectric material in constructing the vertical contact-separation mode TENG. Compared to rPS TENG, the rPS-ZnO TENG exhibited a two-fold enhancement in performance (8.2 V) in output voltage and ∼4.5 fold enhancement (28.1 μW/cm2) in power density. Furthermore, following SA treatment, the triboelectric performance further improved, reaching the highest open circuit voltage of ∼8.8 V and the highest power density of 32.0 μW/cm2 for repeated 2 N-solenoid tapping force. The hydrophobic behavior was also improved with the highest water contact angle of 134.7 (when the SA treatment immersion time was 1 h). These findings demonstrate that SA-treated rPS-ZnO NF could be a promising candidate for efficient mechanical energy harvesting with high electrical output and excellent surface wettability. This research not only exhibits an excellent output performance of SA-treated rPS-ZnO TENG, but it also sheds new light on the sustainable approach of converting polystyrene waste into energy-harvesting material.

Facile Synthesis of Dual-Network Polymer Hydrogels with Anti-Freezing, Highly Conductive, and Self-Healing Properties.

We report the synthesis of poly(acrylamide-co-acrylic acid)/sodium carboxy methyl cellulose (PAMAA/CMC-Na) hydrogels, and subsequent fabrication of dual-network polymer hydrogels (PAMAA/CMC-Na/Fe) using as-prepared via the salt solution (FeCl3) immersion method. The created dual-network polymer hydrogels exhibit anti-swelling properties, frost resistance, high conductivity, and good mechanical performance. The hydrogel swells sightly when immersed in solution (pH = 2~11). With the increase in nAA:nAM, the modulus of elasticity experiences a rise from 1.1 to 1.6 MPa, while the toughness undergoes an increase from 0.18 to 0.24 MJ/m3. Furthermore, the presence of a high concentration of CMC-Na also contributes to the enhancement of mechanical strength in the resulting hydrogels, ascribing to enhanced physical network of the hydrogels. The minimum freezing point reaches -21.8 °C when the CMC-Na concentration is 2.5%, owing to the dissipated hydrogen bonds by the coordination of Fe3+ with carboxyl (-COO-) in CMC-Na and PAMAA. It is found that the conductivity of the PAMAA/CMC-Na/Fe hydrogels gradually decreased from 2.62 to 0.6 S/m as the concentration of CMC-Na rises. The obtained results indicates that the dual-network hydrogels with high mechanical properties, anti-swelling properties, frost resistance, and electrical conductivity can be a competitive substance used in the production of bendable sensors and biosensors.

Development of superhydrophobic surface on mild steel by a facile approach and analyzing its self-cleaning and anti-freezing properties

Superhydrophobic surfaces are currently a subject of great interest because of their tremendous applications. This study offers greater insight into the self-cleaning ability and anti-icing behavior of the superhydrophobic mild steel and finds application in aircraft and marine systems. Superhydrophobic surfaces were developed on the mild steel surface by improving the roughness and reducing the energy on the surface. Mild steel was chemically etched with HCL solution for 10 min to improve the roughness. After etching, the surfaces were immersed in stearic acid solution for 3 h by solution immersion method to introduce low surface energy. The resultant surfaces have a combination of nano and micro-roughness. The roughness of the samples was measured with the aid of surface roughness tester. The roughness of the prepared surface is 4.213 μm. The microstructure of the as-prepared surface was characterized by a scanning electron microscope. The surfaces have changed to be pine-cone-like structure. The pinecone-like hierarchical structures can generate numerous grooves in which the air can be trapped which lead to a larger contact angle. The contact angle was measured by using a goniometer setup. The obtained contact angle of the surface is as high as 154° with a lower contact angle hysteresis. The surfaces were tested for self-cleaning and ice-delaying properties. The as-prepared superhydrophobic surfaces can self-clean the surface from dirt/dust while the water droplets roll over the surface. A freezing delay time of 392 s was achieved on the surfaces. The prepared surfaces possess better self-cleaning and ice-delaying properties.

Solid-State Lithium Batteries with Ultrastable Cyclability: An Internal-External Modification Strategy.

A commonly used strategy to tackle the unstable interfacial problem between Li1.3Al0.3Ti1.7(PO4)3 (LATP) and lithium (Li) is to introduce an interlayer. However, this strategy has a limited effect on stabilizing LATP during long-term cycling or under high current density, which is due in part to the negative impact of its internal defects (e.g., gaps between grains (GBs)) that are usually neglected. Here, control experiments and theoretical calculations show clearly that the GBs of LATP have higher electronic conductivity, which significantly accelerates its side reactions with Li. Thus, a simple LiCl solution immersion method is demonstrated to modify the GBs and their electronic states, thereby stabilizing LATP. In addition to LiCl filling, composite solid polymer electrolyte (CSPE) interlayering is concurrently introduced at the Li/LATP interface to realize the internal-external dual modifications for LATP. As a result, electron leakage in LATP can be strictly inhibited from its interior (by LiCl) and exterior (by CSPE), and such dual modifications can well protect the Li/LATP interface from side reactions and Li dendrite penetration. Notably, thus-modified Li symmetrical cells can achieve ultrastable cycling for more than 3500 h at 0.4 mA cm-2 and 1500 h at 0.6 mA cm-2, among the best cycling performance to date.

Study on the modification mechanism of recycled brick-concrete aggregate concrete based on water glass solution immersion method

Recycling construction waste into concrete through the process of crushing and screening is a vital method of resource conservation. Recycled aggregates often contain imperfections such as micro-cracks, necessitating modification to produce high-performance concrete. Water glass, an economical modifier, addresses this need. However, recycled aggregates often contain concrete and brick aggregates and are difficult to completely separate. At present, there are few studies on the modification of recycled brick aggregates, and there is a lack of comprehensive and systematic research from the aggregate modification mechanism to the macroscopic working performance and mechanical properties of recycled concrete. Based on the above problems, the modification effect and modification mechanism of water glass solution on recycled brick aggregate and recycled concrete aggregate were studied by basic physical properties, SEM, and XRD tests. The relationship between macroscopic mechanical properties and the microstructure of modified recycled brick-concrete aggregate concrete was studied by compressive, flexural, and splitting tensile tests, XRD, NMR, and SEM. The results showed: (1) The best modification scheme for recycled brick aggregate and recycled concrete aggregate is the concentration of water glass solution at 4 % with a soaking time of 5 h; (2) the mechanical properties of recycled brick-concrete aggregate concrete are the best when the brick-concrete ratio is 5:5, and the compressive strength, flexural strength, and splitting tensile strength are increased by 10.84 %, 11.61 %, and 15.08 %, respectively; and (3) the water glass solution improved the pore structure and interfacial transition zone of recycled aggregate. The proportion of harmless pores and less harmful pores increased by 5.66 % and 13.3 %, respectively, and the proportion of harmful pores and more harmful pores decreased by 6.25 % and 12.7 %, respectively. The research results can promote the resource utilization of construction waste.

Bacteriostatic effect of Ag@TiO2-Poly(p-dioxanone)-coated gauzes in vitro and in vivo on otitis media pathogens

The application of packing agents affects the final surgical outcomes in treating otitis media (OM) and introduces the risk of infection. To decrease the infectious risks of packing agents and even introduce positive bacteriostatic functions, a kind of PPDO-grafted Ag-incorporated TiO2 nanoparticles (Ag@TiO2-PPDO NP)-coated gauzes were prepared by a solution immersion method. Morphologies and in vitro Ag+ releasing of Ag@TiO2-PPDO NP coated gauzes were determined by scanning electron microscope (SEM) and inductively coupled plasma-mass spectrum (ICP-Ms). Ag@TiO2-PPDO NP could respond to visible light, which might make Ag@TiO2-PPDO NP inhibit the proliferation of bacteria continually and positively with irradiation of visible light. Then the bacteriostatic effects of these gauzes on OM pathogens were investigated in vitro and in vivo. These gauzes could inhibit the proliferation of pathogenic Staphylococcus aureus (S. aureus) and Streptococcus pneumoniae (S. pneumoniae) in vitro and rat subcutaneous infection models. Specifically, the bacteriostatic effect of these gauzes on S. aureus and S. pneumoniae could be enhanced with irradiation by visible light in vitro. Further, the rat external auditory canal infection model verified the enhanced bacteriostatic effect of Ag@TiO2-PPDO-coated gauzes on S. aureus with irradiation by visible light. The Ag@TiO2-PPDO-coated gauzes are promising for packing materials after OM surgery and could reduce postoperative antibiotic requirements.

Corrosion resistance and adhesive performance of a novel phytic acid-triethoxyvinylsilane-zinc hybrid chemical conversion film on steel

A novel organic-inorganic hybrid chemical conversion film was prepared by phytic acid-triethoxyvinylsilane composite and zinc ions via solution immersion method. The phytic acid-triethoxyvinylsilane composite which contained abundant organic groups was synthesized by the condensation reaction between phytic acid and triethoxyvinylsilane. The results of electrochemical impedance spectroscopic and polarization curves indicate that the anti-corrosion performance of the hybrid films exhibited good anti-corrosion performance and the highest protection efficiency of the fabricated film was 99.79% when the film formation time is 45 min. The salt spraying test and adhesion test indicated that the fabricated hybrid films exhibited the best adhesion performance when the film formation time is 15 min. So the anti-corrosion and adhesion performance of the chemical conversion film may be not agreed. The scanning electron microscope results indicated that the roughness and cracks of the surface of the films may be the main reasons that affect the anti-corrosion and adhesion performances. X-ray photoelectron spectroscopy results demonstrated that phytic acid-triethoxyvinylsilane composite adsorbed on steel surface through the formation of Fe–O–P bonds and the Zn2+ participated the film formation process through the formation of zinc phosphate and ZnO.

High Electrochromic Performance of Perylene Bisimide/ZnO Hybrid Films: An Efficient, Energy-Saving, and Green Route.

The composite or hybrid of organic and inorganic materials is one of the common ways to improve the properties of photoelectric functional materials. Perylene bisimide (PBI) derivatives, as large π-conjugated organic small molecules, are a class of photoelectric functional materials with excellent performance. However, there were few reports on PBIs in the electrochromic field due to the difficulty of film-forming caused by their generally poor solubility. Here, water-soluble PBI derivatives (PDI-COOH and PCl-COOH) were synthesized. The hybrid films (ZnO@PDI-COOH/PCl-COOH) formed by the coordination bond and π-π stacking were prepared via a simple solution immersion method. Fourier transform infrared spectrometry and X-ray diffraction as well as scanning electron microscopy, and energy-dispersive spectrometry results further confirmed the formation of hybrid films. At the same time, electrochemical and spectroelectrochemical analyses revealed that the films have reversible redox activity and cathodic electrochromic properties, which can change from orange-red to purple. The ZnO@PDI-COOH hybrid film formed by coordination bonds exhibits fast switching times (1.7 s colored time and 2.6 s bleached time), good stability (retain 92.41% contrast after 2400 cycles), a low driving voltage (-0.6-0 V), and a high coloration efficiency (276.14 cm2/C). The corresponding electrochromic devices also have good electrochromic properties. On this basis, a large-area (100 mm × 100 mm) electrochromic display device with fine patterning was fabricated by using the hybrid film, and the device shows excellent reversible electrochromic performance. This idea of constructing organic-inorganic hybrid materials with coordination bonds provides an effective, energy-saving, and green method, which is expected to promote the large-scale and fine production of electrochromic materials.

Effect of GO Solution Temperature on the Structural, Optical and Electrical Properties of ZnO Nanostructured for Photoanode Function

The purpose of this study is to determine the effect of different graphene oxide (GO) solution immersion temperature on the structural, morphology, optical, and electrical properties of zinc oxide/graphene oxide (ZnO-GO) nanostructures. The ZnO/GO nanostructures prepared at various GO solution immersion temperature from 75-95℃ using solution immersion method. The structural properties of the samples were investigated using X-ray diffraction (XRD), and the recorded patterns revealed that all the samples had a preferred orientation along the (002) plane. The crystallinity of ZnO/GO nanostructures were enhanced with increasing GO solution immersion temperature. The morphology of ZnO/GO nanostructures was determined using field emission scanning electron microscopy (FESEM). Fourier transformation infrared spectroscopy (FTIR) was used to determine the molecular compounds of ZnO/GO nanostructures. The peak intensity of GO with ZnO nanoparticles is shifted at 744 to 1243 cm-1 when the temperature of GO solutions increases. The UV–visible spectrophotometer was used to examine the optical properties of ZnO/GO nanostructures. It is found that the highest transmittance ZnO/GO nanostructures was obtained at the highest GO solution immersion temperature which is 95℃. Based on the current-voltage(I–V) measurement, the electrical properties of ZnO/GO nanostructures increase when the GO solution immersion temperature increases. Thus, by variation of GO solution immersion temperature the structural, morphology, optical, and electrical behaviour were improved.

Fungal Carboxymethyl Chitosan-Impregnated Bacterial Cellulose Hydrogel as Wound-Dressing Agent.

Bacterial cellulose (BC) produced by Gluconoacetobacter hansenii is a suitable polymeric fiber network for wound-dressing purposes, but its lack of antibacterial properties limits it from healing bacterial wounds. We developed hydrogels by impregnating fungal-derived carboxymethyl chitosan to BC fiber networks using a simple solution immersion method. The CMCS-BC hydrogels were characterized using various characterization techniques such as XRD, FTIR, water contact angle measurements, TGA, and SEM to know the physiochemical properties. The results show that the impregnation of CMCS into BC fiber networks greatly influences BC's improving hydrophilic nature, which is crucial for wound healing applications. Furthermore, the CMCS-BC hydrogels were studied for biocompatibility analysis with skin fibroblast cells. The results revealed that by increasing the CMCS content in the BC, biocompatibility, cell attachment, and spreading capacity also increase. The antibacterial activity of CMCS-BC hydrogels is shown using the CFU method against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). As a result, the CMCS-BC hydrogels exhibit more suitable antibacterial properties than those without BC due to the CMCS having amino groups that enhance antibacterial properties. Therefore, CMCS-BC hydrogels can be considered suitable for antibacterial wound dressing applications.

Preparation and Properties of a Novel Biodegradable Composite Hydrogel Derived from Gelatin/Chitosan and Polylactic Acid as Slow-Release N Fertilizer

To improve the efficient use of nitrogen and decrease the environmental pollution of N losses, a novel and biodegradable composite hydrogel was prepared by chemical cross-linking synthesis using gelatin (Gel), chitosan (CS) and polylactic acid (PLA) as raw materials. Urea as the nitrogen source was loaded into this new biodegradable hydrogel using the solution immersion method. The chemical structures of the composite hydrogels were characterized and their properties were analyzed by XRD and XPS. The regulation of urea loading and the swelling behavior of the composite hydrogel under different temperature conditions were investigated; the release behavior and release model of the composite hydrogel in the aqueous phase was explored. The results show that the loading of urea is controllable in aqueous urea solution with different concentrations. In the water phase, it shows a three-stage sustained release behavior, that is, the initial release rate of urea is relatively fast, and the medium release rate of urea gradually slows down, and finally the nutrient release rate tends to be flat. The release behavior in the water phase fits to the Ritger-Peppas model. Within 10 min, 180 min and 900 min, the cumulative nutrient release rate of gelatin/chitosan/PLA-urea (GCPU) composite hydrogel is 20%, 70% and 86%, respectively. Compared with pure urea, The urea diffusion time of GCPU was extended by 1350-times. In addition, the GCPU also has good water absorption and water retention properties, in which average water content can reach as high as 4448%. All of the results in this work showed that GCPU hydrogel had good water absorption and retention and N slow-release properties, which are expected to be widely used in sustainable agriculture and forestry, especially in arid and degraded land.

Effect of Superhydrophobic Surface on Corrosion Resistance of Magnesium-Neodymium Alloy in Artificial Hand Sweat

A superhydrophobic surface can endow metals with some intriguing characteristics such as self-cleaning behavior. In this study, a simple solution-immersion method based on the concept of predesigned corrosion is developed to enhance the corrosion resistance of a magnesium-neodymium alloy. The Mg alloy is directly soaked in potassium dihydrogen phosphate solution with the addition of ultrasound, and a layer of rough but dense coating is uniformly formed on the Mg-Nd alloy after the immersion process, which is mainly composed of MgHPO4∙3H2O. A superhydrophobic surface with an average wetting angle of 150.5° and a sliding angle of about 4.5° can be obtained on the Mg alloy by further chemical surface modification with perfluorodecyltriethoxysilane. This superhydrophobic surface has an interesting self-cleaning effect as well as good corrosion resistance in artificial hand sweat. In brief, this study provides a feasible way to prepare a superhydrophobic surface on the Mg-Nd alloy and reveals the effect of a superhydrophobic surface on the corrosion behavior of the Mg-Nd alloy, offering new technical insights into the corrosion protection of magnesium alloys.

Formation of a Nanorod-Assembled TiO2 Actinomorphic-Flower-like Microsphere Film via Ta Doping Using a Facile Solution Immersion Method for Humidity Sensing.

This study fabricated tantalum (Ta)-doped titanium dioxide with a unique nanorod-assembled actinomorphic-flower-like microsphere structured film. The Ta-doped TiO2 actinomorphic-flower-like microsphere (TAFM) was fabricated via the solution immersion method in a Schott bottle with a home-made improvised clamp. The samples were characterised using FESEM, HRTEM, XRD, Raman, XPS, and Hall effect measurements for their structural and electrical properties. Compared to the undoped sample, the rutile-phased TAFM sample had finer nanorods with an average 42 nm diameter assembled to form microsphere-like structures. It also had higher oxygen vacancy sites, electron concentration, and mobility. In addition, a reversed double-beam photoacoustic spectroscopy measurement was performed for TAFM, revealing that the sample had a high electron trap density of up to 2.5 μmolg-1. The TAFM showed promising results when employed as the resistive-type sensing film for a humidity sensor, with the highest sensor response of 53,909% obtained at 3 at.% Ta doping. Adding rGO to 3 at.% TAFM further improved the sensor response to 232,152%.

Highly stable 3D Li metal anodes enabled by a shielding/rectifying polymer layer

The practical application of Li metal anode is hindered by the uncontrollable dendrites growth, severe side reactions and huge volume fluctuation, which would result in low Coulombic efficiency (CE) and poor cycling performance. Herein, a 3D Li host is functionalized by a low-cost and environment-friendly polyvinyl alcohol (PVA) layer via a facile solution immersion method to solve the above issues. The polymer layer can act as a stable artificial SEI with high ionic conductivity during cycling, so as to isolate the direct contact between Li metal and electrolyte and then avoid interfacial side reaction. In addition, the abundant hydroxyl (−OH) polar groups in PVA, which own a strong binding energy with Li atoms, can effectively regulate Li plating/stripping behaviors on the 3D framework. As a result, the symmetric cell using PVA-Cu mesh-Li electrode delivers a superior long-term stability over 1000 h with a low average voltage hysteresis of 17 mV at 1 mA cm−2. And the PVA-Cu mesh-Li || LiFePO4 full cell can remain a high discharge capacity of 104.4 mAh g−1 and a high CE of 99.1% after 350 cycles at 5 C.

Thermal and magnetic dual-responsive switchable device with superhydrophilicity/underwater superoleophobicity and excellent targeted oil–water separation performance

In view of the increasingly serious problem of oil–water separation, it is a convenient and practical method to introduce a hydrogel coating on the surface of materials to make super-wetting materials. Nowadays, researchers of super-wetting materials pay more attention to the research and development of responsive materials. Here, a thermal and magnetic dual-responsive superhydrophilicity/underwater superoleophobicity switchable device (Fe3O4@PNIPAM-Cu) was simply fabricated using the Fe3O4 nanoparticles, poly-N-isopropylacrylamide (PNIPAM) hydrogel as the functional coating and copper foam as the skeleton through a one-step solution immersion method. The separation efficiency of the benzene-water mixture of this dual-responsive device can reach up to 99.98%. Even after 10 separation cycles, it maintained an efficiency of more than 99.90%. At temperatures above ~34°C, the device can stop oil–water separation. The experiments presented here demonstrate this dual-responsive device possesses excellent superhydrophilicity/underwater superoleophobicity, thermal-responsive property and magnetic navigation function.

Enhancing antioxidant properties of hydrogen storage alloys using PMMA coating

Oxidation of hydrogen storage alloy leads to the formation of a passive surface oxide layer, which deteriorates its performance. This study introduces a method utilizing polymethyl methacrylate (PMMA) nano-coating to improve the antioxidant properties of hydrogen storage alloys, including LaNi5, TiMn2, and Mg2Ni. PMMA nano-coating was achieved using a solution immersion method. The results show that the PMMA-coating promotes a stable capacity, kinetics, and thermodynamic properties compared to those of uncoated alloys. After 168 h of air exposure, the hydrogen storage capacities of PMMA-coated LaNi5, TiMn2, and Mg2Ni alloys show minor decreases. Moreover, cycling tests demonstrate that PMMA-coated LaNi5 and PMMA-coated Mg2Ni have good cyclic stabilities. Our results show that the PMMA coating provides effective protection for variant hydrogen storage alloys from oxygen contamination and oxidation.

Comparative study of surface, elemental, structural and optical morphologies of titanium dioxide-zinc oxide (TiO2-ZnO) and titanium dioxide-zinc oxide/graphene (TiO2-ZnO/Gn)

The aim of this study is to synthesize a highly dense nanosized TiO2-ZnO sample with graphene (TiO2-ZnO/Gn) thin film via solution immersion method and compare its properties with TiO2-ZnO thin film without graphene. To prepare the titanium dioxide solution, the titanium butoxide precursor was added to ethanol, glacial acetic acid and triton-x-100 with a drop of deionized water. Next, to prepare for the ZnO/Gn solution, the zinc nitrate hexahydrate was added to hexamethylenetetramine (HMTA). Then, a specific weight of graphene was added into the solution before left for ageing. The thin films will be characterized in order to consider and enhance the potential of TiO2-ZnO/Gn thin film in treating wastewater. Ultra-Violet Visible spectroscopy (UV–vis), X-ray Diffraction (XRD), and Field Emission Scanning Electron Microscopy (FESEM) were used to determine the optical, structural and morphological properties of the samples. From the UV–vis absorption spectra, the TiO2-ZnO/Gn shows the better UV–vis performance compared to the TiO2-ZnO sample. While the FESEM images for TiO2-ZnO/Gn confirmed the presence of the Gn deposited on the thin film with specific grain-like structures of TiO2, hexagonal nanorod ZnO and wrinkles shape of Gn. Finally, the XRD analysis confirmed the crystallinity of the samples, and the elements present on the glass substrate. It has shown that there are TiO2, ZnO and Gn peaks present in the XRD patterns. Thus, TiO2-ZnO/Gn is the best candidate to be used as the photocatalyst in treating the wastewater.