Porous Powder Research Articles

Hard Carbon Derived from Avocado Peels as a High-Capacity, Fast Na+ Diffusion Anode Material for Sodium-Ion Batteries

Deriving battery grade materials from natural sources is a key element to establishing sustainable energy storage technologies. In this work, we present the use of avocado peels as a sustainable source for conversion into hard carbon-based anodes for sodium ion batteries. The avocado peels are simply washed and dried then proceeded to a high temperature conversion step. Materials characterization reveals conversion of the avocado peels in high purity, highly porous hard carbon powders. When prepared as anode materials they show to the capability to reversibly store and release sodium ions. The hard carbon-based electrodes exhibit excellent cycling performance, namely, a reversible capacity of 352.55 mAh g−1 at 0.05 A g−1, rate capability up to 86 mAh g−1 at 3500 mA g−1, capacity retention of >90%, and 99.9% coulombic efficiencies after 500 cycles. Cyclic voltammetry studies indicated that the storage process was diffusion-limited, with diffusion coefficient of 8.62 × 10−8 cm2 s−1. This study demonstrates avocado derived hard carbon as a sustainable source that can provide excellent electrochemical and battery performance as anodes in sodium ion batteries.

Waste to treasure: Superwetting foam enhanced by bamboo powder for sustainable on-demand oil-water separation

Low-cost and sustainable superwetting materials are urgently required for oily wastewater treatment. Many poly(vinylidene fluoride) (PVDF)-based materials have been designed for oil-water separation. However, their fabrication processes frequently require toxic organic solvents and high-cost materials (e.g., carbon tubes and graphene). In this study, a highly porous and superhydrophobic bamboo powders (BP)-enhanced PVDF foam (SBPF) was fabricated via an organic solvent-free process. The SBPF exhibits efficient adsorption and recovery for various oils and organic solvents. Moreover, the SBPF shows high adsorption and separation performance under ultraviolet exposure and turbulent environments. It can also be used for water-in-oil emulsions separation, with a high separation efficiency more than 99.3 % under gravity. Interestingly, the amphiphilic PVDF-BP foam (ABPF) shows underwater superoleophobicity and underoil superhydrophobicity after delignification of SBPF. Owing to the conversion of wettability, it presents a high performance in treatment of both surfactant-stabilied water-in-oil and oil-in-water emulsions with the high separation efficiency achieving more than 99.6 % and 99.5 % respectively under gravity. In addition, the ABPF shows a high separation performance even after ten cycles. Hence, this fabricated organic solvent-free foams are promising candidates for sustainable on-demand separation of oils or organic solvents and water in complex environments.

Activated carbon synthesized from bamboo shoots for supercapacitor application

Carbon powder was synthesized from bamboo shoots by chemical activation. The porous carbon powders were activated by potassium hydroxide (KOH) with a ratio of carbon powder (C) and KOH (C : KOH) of 1 : 1, 1 : 2, 1 : 3, and 1 : 4 by weight, respectively. Structure, morphological properties, and the porosity of activated carbon powders were investigated by XRD, EDX, SEM, and BET. The electrochemical performances were measured by charge/discharge (CD) and cyclic voltammetry (CV) techniques. Specific surface areas increased to1,017,1,162,1,257,and1,012m2 g−1 forC:KOHratiosof1:1,1:2,1:3,and1:4, respectively. Specific capacitances were 11.30, 26.60, 50.50, and 40.50 F g–1 for the C : KOH ratios of 1 : 1, 1 : 2, 1 : 3, and 1 : 4, respectively. The activated carbon electrode with a C: KOH ratio of 1 : 3 sintered at 600 °C displayed the highest specific capacitance value of 50.5 F g–1. It should be a good candidate material for high-performance supercapacitor electrodes.

Properties and Durability of Cement Mortar Using Calcium Stearate and Natural Pozzolan for Concrete Surface Treatment.

Applying a concrete surface treatment method (epoxy or primer) can prevent water from penetrating concrete through surface pores. However, if the concrete surface is damaged, the subsequent reconstruction can be expensive and time-consuming. Concrete that is resistant to internal and external water has been extensively developed and used to supplement the surface treatment method. Herein, we prepared specimens by mixing cement mortar with fatty-acid-salt-based calcium stearate attached to two natural pozzolanic materials—diatomite and yellow clay. The physical tests measured (1) the air content, (2) flow test, (3) compressive strength, and (4) activity Factor. Durability experiments were performed on (1) the contact angle, (2) chloride ion diffusion coefficient, and (3) water absorption test. The results revealed that the compressive strength of concrete decreased as the calcium stearate content increased. Furthermore, it was confirmed that the contact angle of the test piece using the pozzolanic substance and calcium stearate was twice as high. It was confirmed that the sand test specimen had the highest water absorption rate, and the DT3% had the lowest. (Sand%: 11.8 > OPC: 6.5 > DT3%: 2.4), the chloride diffusion coefficient also showed similar results. (Sand%: 12.5 > OPC: 8.4 > DT1%: 8.8)Due to its unique insolubility, calcium stearate retards hydrate formation when mixed alone and negates compressive strength loss when combined with pozzolanic mixtures rich in SiO2 and Al2O3. Furthermore, the ideal method for producing water-resistant cement mortar is to evenly disperse calcium stearate in the porous powder of cement mortar.

Ca2Fe2O5 powder antifungal activity to the Candida utilis culture upon its growth.

This study reports the impact of Ca2Fe2O5 porous powder on the yeast Candida utilis-as a fungal model-at different phases of growth, i.e., early exponential (6h), mid-log (11h), and stationary (17h) phases. Ca2Fe2O5 inhibited the cell growth in a time-dependent manner. After 120min incubation, the fungicidal activity of porous powder was observed, i.e., log reduction of 2.81 and 2.58 for 11 and 17h cultures, respectively, reaching the maximum of 4 log reduction after 7 days. Nevertheless, the 6h culture of C. utilis showed enhanced resistance to Ca2Fe2O5 with a ≤ 0.4 log reduction during the 7 days exposure. Our results not only showed that Ca2Fe2O5 has the potential to effectively eliminate the C. utilis cell growth but also indicated the importance of the yeast culture physiological state for resistance to Ca2Fe2O5. To the best of our knowledge, this is the first study that evaluated the fungicidal activity of Ca2Fe2O5 porous powder on C. utilis and the impact of the C. utilis phase of growth on the cell susceptibility.

Solar-assisted efficient cleanup of high-viscosity oil spills using magnetic porous biochar

Efficient cleanup of oil spills is still a global challenge due to the high viscosity of crude oil and complicated topographic features. Herein, magnetic porous carbon powders (MPCs) with photothermal effect prepared at a Fe(NO3)3: bamboo mass ratio was 1/1 carbonized at 700 °C. After modifying with the n-octadecylamine, the oleophilic MPCs exhibited rapid and selective absorption of different oils from polluted water, with an optimal absorption capacity of 3.2–8.1 g/g. Since oil's viscosity is highly temperature-sensitive, MPCs with photothermal characteristics offer apparent advantages in absorbing high viscosity oil. Moreover, due to the incorporation of magnetic components, powder-like MPCs can be conveyed to a specified oil pollution spot (including gaps or cracks) conveniently and collected through a remote magnetic field. This work demonstrates a simple and low-cost way of designing and producing oil/water separation materials, particularly floating high-viscosity oil recovery.

Improvement of a capacitive UV-sensor by porous silicon powders embedded in epoxy on porous silicon film

A high-sensitivity porous silicon (PS) powder-based capacitive UV-sensor is developed on the PS-film structure. To the best of our knowledge, this is the first report on PS powder-based capacitive UV-sensors. An anodization etching approach based on a sawtooth waveform electrolytic voltage is adopted to get sufficient PS-powders. The collected PS-powders are embedded on the PS-film and covered with epoxy to improve the UV sensitivity. The results show that the increase of UV sensitivity on capacitive characteristics is almost linearly related to the PS powder mass embedded inside. The proposed method is suitable for fine-tuning and improving the equivalent permittivity of the capacitive UV-sensor without changing the device geometry design, which can be compatibly applied to Si-VLSI technology.

Fe2O3 powder modified with Ce0.6Mn0.3Fe0.1O2 and Cr2O3 prepared by spray pyrolysis method for rechargeable Fe–air cell

AbstractHighly porous and uniform sphere shape Fe powder with a nano‐porous structure can be prepared successfully with a spray pyrolysis method and applied for solid oxide Fe–air rechargeable battery, which is consisted of solid oxide reversible cells using an H2O/H2 redox mediator. The prepared Fe powder modified with both Cr2O3 and Ce0.6Mn0.3Fe0.1O2 shows a high redox reaction rate as well as cycle stability by uniform distribution. A discharge capacity of 1100 mAh·g‐Fe−1 with almost 100% coulombic efficiency was achieved at initial cycles and that larger than 800 mAh·g‐Fe−1 was sustained over 20 cycles at 873 K. After the reduction of Fe powder with H2 flow so‐called chemical charge, a discharge capacity of 900 mAh·g‐Fe−1 was recovered and stably sustained for the following 20 cycles (40 total cycles), and discharge capacity may be sustained further longer cycles at 823 K. The round‐trip efficiency for charge and discharge was about 90%, which can be assigned to the high reversibility of Fe redox with nano‐porous structure prepared by spray pyrolysis method.

(Digital Presentation) Novel Porous Functionalized Mwcnts-TiO2/g-C3N4 heterostructure Modified Screen Printed Electrode for a Rapid Enzyme-Free Detection of Uric Acid in Human Urine

Porous heterostructures gained wide appreciation for their escalated sensing performance in electrochemical society. In the present work, we report the porous functionalized MWCNTS-TiO2/g-C3N4 (f-MWTGCN) heterostructure modified screen-printed electrode for the detection of uric acid in human urea samples. The f-MWTGCN are synthesized via a two-step combination process by hydrothermal-assisted ultrasonication construction. The fabricated powders are subjected to X-Ray diffraction to identify the size, structure, dislocation densities, and micro strain. The morphological studies are performed by the FESEM and HRTEM analysis to identify the confinement of heterostructures. The required chemical analysis was obtained from the FTIR and Raman studies and substantiated the qualitative and quantitative vibrational modes. The obtained highly porous ultrafine powders are drop cast on the screen-printed electrode to modify the working electrode to achieve super ultrafast sensing. Functionalization of MWCNTs facilitated the carbon to attain hydroxyl, carboxyl, and carbonyl functional groups which assisted in the rapid detection of uric acid. The reproducibility and stability of the electrode were evaluated by the fifteen repeated cyclic voltammetry responses to 0.1M uric acid. The developed sensors showcased a detection of Limit (DoL) of 1.17 µM and sensitivity of 98.1 nA µM-1 with a range of two to three seconds. The utilization of the developed heterostructure for modifying screen-printed electrodes and sensing uric acid is a unique and novel approach. Thus, the fabricated highly stable sensor may be utilized as the uric acid sensor in biomedical applications. Keywords: Porous, Heterostructures, Functionalized MWCNTS, Reproducibility, and Hydrothermal.

Proliposome: A Novel Solution for the Stability of Liposomes - A Review

Proliposome are phospholipid-based vesicular drug delivery systems that have specialized applications in drug delivery via various routes of administration. They are widely researched as potential carriers for improving bioavailability through oral administration of drugs with low bioavailability and are composed of the drug, phospholipid, and a water-soluble carrier or porous powder. The technology is based on the inherent ability of hydrated membrane lipids to form liposomal vesicles when exposed to water. It is specifically designed for molecular dispersion and delivery of hydrophilic and hydrophobic drugs to achieve good bioavailability, local, systemic effects, and site-specific drug delivery strategies. By utilizing phospholipids and various carriers, these vesicular systems play critical roles in improving bioavailability and solubility. An in-depth understanding of the physical and biological behavior of Proliposome is required for designing an effective delivery system that will increase drug availability at the anticipated site. Proliposome provide an opportunity to improve drug therapeutic action by modifying drug uptake mechanisms. The Proliposome approach was developed as a simple, repeatable, and dependable manufacturing technique for large-scale production of liposome dispersions. The present review discusses the use of Proliposome to improve the oral bioavailability of poorly water-soluble drugs, components for the formulation, effects of excipients, techniques for preparation, evaluation of Proliposome, and other key issues related to various routes of administration. Proliposome formulation is an alternative, novel solution for liposome stability.

High-strength microporous corundum-mullite refractory aggregates with sub-micron pores using vacuum impregnation treatment

A novel route was proposed to decrease the pore size and enhance the strength of microporous corundum-mullite refractory aggregates, which were fabricated by using the vacuum impregnation treatment of porous Al2O3 powder with silica sol. The effect of the SiO2 content (0–23.6 wt. %) on the phase composition, microstructures and physical properties of the refractory aggregates was studied. It was found that the sub-micron pore structure inside the pseudomorph particles was effectively preserved due to the volume expansion effect of mullite and the mullite sintering neck formation between the α-Al2O3 microcrystallites. With the SiO2 content increasing from 0 to 13.0 wt. %, the pseudomorph particles containing a large number of sub-micron pores formed in the refractory aggregates resulting from the introduction of silica sol. This resulted in the decrease of intra-particle pore size as well as the development of mullite sintering necks between the pseudomorph particles. The strength of the refractory aggregates was therefore enhanced. With a further increase of SiO2 content to 16.4 and 23.6 wt. %, the inter-particle pore sizes increased due to the mullite volume expansion between the pseudomorph particles, which was responsible for the decrease of strength. Overall, the optimized product is the microporous corundum-mullite refractory aggregates with the addition of 13.0 wt. % SiO2, which showed an apparent porosity of 45.4% and a high compressive strength of 56.4 MPa. Significantly, it also had a median pore size of only 1.24 μm and contained a large number of sub-micron pores.

Porous, colorful and gas-adsorption powder from wool waste for textile functionalization

Textile waste is a fast-growing challenge and a large quantity of used textile ends up in landfills and incineration plants, which can pollute the environment through the production of toxic substances and greenhouse gases. This work explores the utilization of waste wool in a circular context by mechanically transforming it into wool powder for reusing as sustainable additives for textile functionalization. A comprehensive investigation was conducted to understand the performance of fabrics coated with wool powder in adsorbing ammonia and formaldehyde based on monitoring their dynamic adsorption behavior using time-resolved infrared spectroscopy. In addition, the application of dyed wool powders as eco-friendly colorants for surface modification of textiles was explored and the performance of the colored powders in gas adsorption was investigated. Compared with ordinary wool fibers, the prepared powders possessed increased surface area, higher surface energy and a more heterogeneous surface. These properties made wool powder an ideal candidate for gas adsorption applications. The adsorption efficiencies of 66% and 62% were achieved in removing ammonia and formaldehyde by coated fabrics, respectively, which are significantly higher than the performance of ordinary wool fibers. Furthermore, the coated polyester fabrics showed an excellent cycling performance for both ammonia and formaldehyde (recovery yield up to 68.1%). The reuse of waste wool for functional modification of fabrics not only extends the practical applications of waste resources, but also alleviates the negative effect of textile disposal on the environment.

Enhancing the electrical and thermal conductivity of polypropylene composites through the addition of Sb–SnO2/coal gasification fine slag porous microbead powder

Conductive powders comprised of coal gasification fine slag porous microbeads/antimony-doped tin oxide nanoparticles (Sb–SnO2/CM, ATCM) have been prepared via acid leaching and coating. The lowest powder volume resistivity of 2.6 × 103 Ω cm was obtained upon leaching in 20% HCl and coating with a 30 wt% solution of Sb–SnO2 (pH = 1, Sn/Sb = 6:1). Subsequently, we prepared a 20 wt% ATCM/polypropylene (PP) composite with a volume resistivity of 4.93 × 109 Ω cm, tensile strength of 29.03 MPa, and thermal conductivity of 0.137 W/(m·K), which reached 0.187 W/(m·K) at a 70 wt% loading. When compared with several commercial conductive fillers, such as carbon black, graphene, Sb–SnO2, and Sb–SnO2@TiO2, 20 wt% ATCM/PP has been proven superior or comparable to most of its counterparts in terms of the improved antistatic properties, enhanced thermal conductivity (only lower than Sb–SnO2@TiO2), and mechanical strength (equal to Sb–SnO2). These good performances were found to be derived from the unique ATCM structure with Sb–SnO2 nanoparticles deposited onto the mesopores and surface of CM. This structure prevents the agglomeration of Sb–SnO2 and provides abundant conductive networks. ATCM also shows a decorative light brown color and low cost (15 USD/kg), which are favorable for industrial production. Our results lay a theoretical foundation for the future applications of ATCM.

Fabrication and microwave absorbing property of WO3@WC with a core-shell porous structure

Special microstructure can significantly improve the microwave absorption property of rare materials. In this paper, porous WC powders were successfully synthesized by spray granulation method. Then, WO3@WC materials with core-shell porous structure can be prepared after 410 °C heating treatment at different time to form the outer WO3 oxidation layer. In addition, the microstructure, morphology, phase analysis and electromagnetic property were fully studied by investigating the WC-based materials in different structures. For WO3@WC core-shell porous materials, when the coating thickness was 2.1 mm, the maximum reflection loss can reach −19.4 dB at 12.6 GHz, which shows quite good microwave absorbing effects. The core-shell porous structure enhances the original microwave absorption performance due to the multiple reflection reflections and polarizations.

Solution Combustion Synthesis, Characterization, Photocatalytic Activity and Electrochemical Studies of Yttrium Stabilised Zirconia (Zr0.72 Y0.28 O1.862) Nanopowder

Background: Yttria stabilized zirconia (YSZ) is an attractive material which exhibits a characteristic combination of physical and chemical properties of YSZ in terms of inertness, resistant to corrosion, high mechanical strength, thermal stability, chemical stability and photostability. Because of these properties and applications, it is very important to synthesize yttrium stabilized zirconia (YSZ) powder. Till date, various preparative techniques have been reported for the synthesis of high porous YSZ nano powders. However, special equipment, long time with multistep processing, high calcination temperature, small surface area and low product yield are the usual drawbacks of most of the methods. Therefore. Solution combustion method (SCS) method has been established for the synthesis of YSZ nanopowder with high surface area. Objective: The main objective of our present research work is to effectively synthesized the Yttrium stabilized zirconia (YSZ) Zr0.72 Y0.28 O1.862 nanopowder by solution combustion method using yttrium nitrate (Y(NO3)3.6H2O), zirconyl nitrate (ZrO(NO3)2.XH3O) as oxidizers and ethylenediamine tetra acetic acid (EDTA) as a fuel and the synthesized powder was used in the application of photodegradation of dyes. Methods: YSZ nanopowder was synthesized by using Solution combustion synthesis. Solution combustion synthesis (SCS) is a simple exothermic self-sustaining one step chemical reaction, which will produce a large number of pores in the oxide material and inhibit their agglomeration leading to a large specific surface area and small crystallite size of the resulting material. Results and Discussion: Powder X-ray diffraction (PXRD) revealed the formation of pure cubic phase of YSZ (Zr0.72 Y0.28 O1.862) nanopowder and the crystallite size of 15.4 nm was calculated by using Scherrer’s formula. The porous morphology of the product was observed by SEM images. BET surface area reveals that the relatively larger surface area of 87.17 m2g-1. TEM analysis revealed uniform particle size distribution with average particle sizes varying in the range of 20-100 nm. The UV-Vis DRS spectrum was used to calculate the absorption wavelength (339 nm) and the corresponding band gap (3.72 eV) using Tauc plot. The photoluminescence spectrum of YSZ nanopowder showed an emission peak at 339 nm. The photodegradation (decolourisation) of methylene blue (MB) dye was increased from 75-90% with increase in the concentration of YSZ photocatalyst from 100 mg to 400 mg due to availability of OH radicals in the presence of UV radiation. The electrochemical studies using cyclic voltammetry reveal a substantial increase in current density of YSZ electrode from 0.0001A to 0.0005A when compared with bare carbon electrode and the instantaneous rise in redox current for the YSZ electrodes from 0.0001A to 0.0005A with increasing scan rate from 10 mVs-1 to 90 mVs-1. Conclusion: In our reported work, we start a simple and rapid solution combustion synthetic approach to produce highly effective YSZ nanopowder using EDTA as organic fuel. Because of large surface area and small particle size of the YSZ nanopowder shows 85% of degradation of MB takes place in presence of UV light. In order to understand the electrochemical property of YSZ, the redox current measurement was carried out using cyclic voltametry and resulted that increase in redox current for the YSZ electrodes with increasing scan rate from 10 mVs-1 to 90 mVs-1.

Preparation of a Novel Solid Phase Microextraction Fiber for Headspace GC-MS Analysis of Hazardous Odorants in Landfill Leachate

The practice of odorant analysis can often be very challenging because odorants are usually composed of a host of volatile organic compounds (VOCs) at low concentrations. Preconcentration with solid phase microextraction (SPME) is a conventional technique for the enrichment of these volatile compounds before analysis by headspace gas chromatography-mass spectrometry (GC-MS). However, commercially available SPME products usually bear the defects of weak mechanical strength and high cost. In this work, novel SPME fibers were prepared by a one-pot synthesis procedure from divinylbenzene (DVB), porous carbon powder (Carbon) and polydimethylsiloxane (PDMS). Factors that influence the extraction efficiency, such as extraction temperature, extraction time, salting effects, pH, stirring rate, desorption temperature and time, were optimized. VOCs in landfills pose a great threat to human health and the environment. The new SPME fibers were successfully applied in the analysis of VOCs from the leachate of a cyanobacteria landfill. Quantification methods of major odor contributors were established, and a good linearity (r > 0.998) was obtained, with detection limits in the range of 0.30–0.50 ng/L. Compared to commercial SPME fibers, the new material has higher extraction efficacy and higher precision. Hence, it is suitable for the determination of hazardous odorants of various sources.

Vacuum impregnation treatment of microporous Al2O3-MgAl2O4 refractory raw materials with sub-micron pores and high strength

In the present work, we propose a novel method to decrease the pore size as well as to enhance the strength of microporous Al2O3-MgAl2O4 refractory raw materials, which were prepared by the vacuum impregnation treatment of porous Al2O3 powders with at MgCl2 solution. The effect of the MgCl2 content (0–32.5 wt%) on the phase distribution, microstructures, and physical properties of the refractory raw materials was thoroughly investigated. The results demonstrated that the sub-micron pore structure inside the pseudomorph particles was effectively preserved due to the volume expansion effect of spinel and the spinel sintering neck formation between Al2O3 microcrystallites. With the MgCl2 content increasing from 0 to 11.9 wt%, the pseudomorph particles contained many sub-micron pores resulting from the introduction of the MgCl2 solution, resulting in the decrease of the intra-particle pore size as well as the development of spinel sintering necks between pseudomorph particles. The strength of the aggregates was therefore enhanced. With a further increase of MgCl2 content to 24.2 and 32.5 wt%, the inter-particle pore sizes increased due to the volume expansion and Kirkendall effect associated with the spinel formation between pseudomorph particles, which were responsible for the progressive decrease of the strength. Overall, the optimized samples were microporous Al2O3-MgAl2O4 refractory aggregates with the addition of 11.9 wt% MgCl2, which exhibited an apparent porosity of 45.0%, a high compressive strength of 45.6 MPa, a median pore size of only 1.49 µm, and a high sub-micron pore volume content of 42.5 vol%. Meanwhile, it is possible to obtain the porous Al2O3-MgAl2O4 powders with a large number of sub-micron pores by crushing and sieving the optimized aggregates.

Composition and structure of calcium-phosphate coatings on Ti3AlC2 produced by sol-gel synthesis

Calcium phosphate materials have been widely used in medical practice for decades. Due to their bioactivity and integration with human hard tissues. They have been produced in the form of dense and porous ceramics, powders and needle-like crystals (whiskers). Despite the high mechanical properties (hardness, compressive strength), calcium phosphate ceramics are mainly used in medicine mainly as the fillers for bone defects formed due to injuries or diseases because they have high fragility and low crack resistance. These circumstances do not allow using them in the sites that have high mechanical loads (e.g. hip surgery). To solve these problems metal implants are used. Among them, Ti-based alloys are the most widely used due to its high mechanical properties, biocompatibility and high corrosion resistance. Recently, the data on the use of MAX phases as medical materials to create the composites based on Ti3SiC2 have appeared in the literature. Calcium phosphate coatings were obtained on Ti3AlC2 substrate by the sol-gel method. The effect of temperature, holding time, chemical compositions of reactants on the phase composition and structure of the samples are discussed. XRD measurements have revealed that the initial coatings consists of nanoparticles sized 10-50 nm. Light and scanning electron microscopy (SEM) were applied to study the morphology of the coatings. It have been shown that the coatings had thickness in an interval 40-100 mm and had the homogenous structure. It has been established by X-ray phase identification that the coating after heating at 1000oC during 1 hour contained b-tricalcium phosphate (b-TCP). It was found, that the thickness and phase composition of coatings depend on the time of coating in calcium phosphate solution. The optimal conditions for the formation of coatings are established.

Tuning the Porous Structure in PMMA-Templated Mesoporous MoO2 for Pseudocapacitive Li-Ion Electrodes

MoO2 is an exciting candidate for next-generation energy storage. It can be used for fast-charging applications in nanoscale form, but its kinetic performance is often limited by insulating MoO3 surface oxide layers. Here, we developed methods to produce polymer-templated porous MoO2 powders where electrical conductivity was well-maintained throughout the structure, even in the presence of some surface oxidation. Porosity, pore size, and crystallite size were controlled by varying the amount and size of the colloidal templates and through calcination temperature. The electrochemical performance was correlated with nanoscale structure: samples with high porosity, medium pore sizes, and good crystallinity display optimal rate capabilities, with over 100 mAh g−1 delivered in 3 min and 93% capacity retention after 1000 cycles. Kinetic studies were performed on samples with the largest and smallest crystallite sizes to understand the charge storage mechanism. In the sample with the smallest crystallite size, 85% of the total stored charge was capacitive, compared to 60% for the largest crystallite size. Sloping voltage profiles in materials with smaller domain sizes further suggest suppression of intercalation-induced phase transitions. This work thus provides insights into the mechanisms of charge storage in nanoscale MoO2 and design parameters for the production of fast charging materials.

Development of carrot top powders using foam mat drying

Carrot tops are under-exploited greens despite having high nutritional value. The effect of ovalbumin and Emustab® concentration and whipping time on foam characteristics was evaluated, and 10% (w/w) of Emustab® and 10 min of whipping was selected for use. Foam mat drying was performed at 50–70°C, and effects of temperature on physicochemical properties, morphology, and centesimal composition of the powders were investigated. Midilli and Kucuk’s model best represented the drying kinetics (R2 = 0.994). Increasing temperature reduced drying time by more than three-fold and significantly (p < .05) affected the moisture content (6.15–11.82% d.b.), hygroscopicity (1.27–2.57%), rehydration ratio (3.30–3.77), and total color difference (14.07 < ΔE < 16.77) of the carrot tops’ powders. Powder at 50°C showed higher moisture content, lower hygroscopicity, and better rehydration rate. Drying at 70°C produced powders with lower ΔE and higher protein content. For all drying conditions, however, fresh carrot tops yielded stable and porous powders, promising for use in ready-to-cook foods. Practical applications Carrot tops are one of the most underutilized greens of appreciable nutritive value. The foam mat drying proved to be promising for the dehydration of these materials, being the carrot top powders extensively characterized to know its properties and variations caused by drying. The results obtained will benefit both researchers and industry professionals to design better drying processes and innovative products based on carrot tops.