Roles of Catalysts in Plasma Conversion of N and H to NH: Advances, Challenges, and Future Directions.

The increasing promotion of a hydrogen-based economy and the use of low-carbon energy sources is critical to the global drive toward carbon neutrality by 2050, and ammonia is among the most promising intermediate products. The current industrial method for ammonia synthesis is the Haber-Bosch (H-B) process, which requires large amounts of fossil fuels, high temperatures and pressures, significant capital investment, and environmental issues. An alternative research interest focusing on plasma catalysis offers a clean, sustainable, and flexible alternative method to convert nitrogen into active species for ammonia (NH) synthesis, but the science of ammonia synthesis using plasma technologies is still in its infancy.

Low-Temperature Degradation of Aflatoxins via Oxygen Plasma: Kinetics and Mechanism Driven by Atomic Oxygen Flux.

Aflatoxins are toxic organic substances that are synthesized on the surfaces of seeds, nuts, and similar products by some fungi under elevated humidity. They decompose at temperatures well above 130 °C, so standard heating or autoclaving is an obsolete technique for the degradation of toxins on surfaces without significant modification of the treated material. Non-equilibrium plasma was used to degrade aflatoxins at low temperatures and determine the efficiency of O atoms.

Enhanced Mechanical Properties of 3D-Printed Glass Fibre-Reinforced Polyethylene Composites.

Optimisation of the tensile strength of thermoplastic polymer-matrix composites remains a scientific as well as technological challenge for 3D printing technology due to the mass application of composite materials. Inadequate mechanical properties are due to the mismatch in the surface energies of the polymer and fillers. In this study, an additively manufactured composite was 3D-printed and tested.

Plasma Treatment of Cellulose as the First Step in the Synthesis of Second-Generation Biofuel.

Cellulosic ethanol has been an attractive biofuel for over a century. Despite the large scientific interest, the first step of treating cellulose before enzymatic hydrolysis is still inadequate, so the scientific community seeks innovative solutions. Among them, plasma treatment of raw cellulose represents an interesting approach.

Vacuum ultraviolet radiation from gaseous plasma for destruction of water contaminants.

Innovative technological solutions are needed for water decontamination to combat the diverse pollutants present in water systems, as no single optimal decontamination technique is appropriate for all circumstances. Vacuum-ultraviolet (V-UV) radiation is a source of energetic photons that break molecular bonds, producing a plethora of chemically reactive agents, most notably OH radicals, which can cause the degradation of harmful pollutants. Low-pressure gaseous plasma is a good source of V-UV radiation; however, its application to liquid water poses challenges.

Improved Adhesion of Bacterial Cellulose on Plasma-Treated Cotton Fabric for Development of All-Cellulose Biocomposites.

Cellulose produced by bacteria (BC) is considered a promising material for the textile industry, but the fragile and sensitive nature of BC membranes limits their broad applicability. Production of all-cellulose biocomposites, in which the BC is cultivated in situ on a cotton fabric, could solve this problem, but here a new issue arises, namely poor adhesion. To overcome this challenge, cotton fabric was modified with low-pressure oxygen plasma in either afterglow, E-mode, or H-mode.

Proof-of-concept for removing micropollutants through a combination of sub-atmospheric-pressure non-thermal plasma and hydrodynamic (super)cavitation.

The persistence and toxicity of hazardous pollutants present in wastewater effluents require the development of efficient and sustainable treatment methods to protect water resources. In this study, the efficacy and efficiency of a novel combination of two advanced oxidation processes - sub-atmospheric-pressure plasma and hydrodynamic cavitation - were systematically tested for the removal of valsartan (VAL), sulfamethoxazole, trimethoprim, naproxen, diclofenac (DF), tramadol, propyphenazone, carbamazepine, 17β-estradiol (E2) and bisphenol A (BPA). The results show that both sample temperature and plasma power play a role and the highest removal, from 29-99 %, was achieved at 25 ℃ and 53 W of plasma power.

Plasma Treatment of Nanocellulose to Improve the Surface Properties.

Nanocellulose is among the most promising materials for enhancing the mechanical properties of polymer composites. Broad application is, however, limited by inadequate surface properties. A standard technique for tailoring the surface composition and wettability of polymers is a brief treatment with non-equilibrium gaseous plasma, but it often fails when treating materials with a large surface-to-mass ratio, such as cellulose nanofibers.

Evolution of the Surface Wettability of Vertically Oriented Multilayer Graphene Sheets Deposited by Plasma Technology.

Carbon deposits consisting of vertically oriented multilayer graphene sheets on metallic foils represent an interesting alternative to activated carbon in electrical and electrochemical devices such as super-capacitors because of the superior electrical conductivity of graphene and huge surface-mass ratio. The graphene sheets were deposited on cobalt foils by plasma-enhanced chemical vapor deposition using propane as the carbon precursor. Plasma was sustained by an inductively coupled radiofrequency discharge in the H mode at a power of 500 W and a propane pressure of 17 Pa.

Recent Advances in Corrosion Inhibition of Bonded NdFeB Magnets.

Bonded permanent NdFeB magnets are useful in numerous applications, including electric vehicles, and the demand is steadily increasing. A major drawback is corrosion due to inadequate wetting of the magnetic particles by liquid polymers such as polyphenylene sulfide or polyamide. Recently reported methods for corrosion inhibition are summarized, and their applicability is critically evaluated.

Kinetics of Surface Wettability of Aromatic Polymers (PET, PS, PEEK, and PPS) upon Treatment with Neutral Oxygen Atoms from Non-Equilibrium Oxygen Plasma.

The wettability of polymers is usually inadequate to ensure the appropriate spreading of polar liquids and thus enable the required adhesion of coatings. A standard ecologically benign method for increasing the polymer wettability is a brief treatment with a non-equilibrium plasma rich in reactive oxygen species and predominantly neutral oxygen atoms in the ground electronic state. The evolution of the surface wettability of selected aromatic polymers was investigated by water droplet contact angles deposited immediately after exposing polymer samples to fluxes of oxygen atoms between 3 × 10 and 1 × 10 ms.

The Impact of Plasma Surface Treatments on the Mechanical Properties and Magnetic Performance of FDM-Printed NdFeB/PA12 Magnets.

This study presents a novel approach for improving the interfacial adhesion between Nd-Fe-B spherical magnetic powders and polyamide 12 (PA12) in polymer-bonded magnets using plasma treatments. By applying radio frequency plasma to the magnetic powder and low-pressure microwave plasma to PA12, we achieved a notable enhancement in the mechanical and environmental stability of fused deposition modeling (FDM)-printed Nd-Fe-B/PA12 magnets. The densities of the FDM-printed materials ranged from 92% to 94% of their theoretical values, with magnetic remanence (B) ranging from 85% to 89% of the theoretical values across all batches.

Surface Modification of Polymers by Plasma Treatment for Appropriate Adhesion of Coatings.

In this study, recent advances in tailoring the surface properties of polymers for the optimization of the adhesion of various coatings by non-equilibrium gaseous plasma are reviewed, and important findings are stressed. Different authors have used various experimental setups and reported results that scatter significantly and are sometimes contradictory. The correlations between the processing parameters and the adhesion are drawn, and discrepancies are explained.

Recent Progress in Cellulose Hydrophobization by Gaseous Plasma Treatments.

Cellulose is an abundant natural polymer and is thus promising for enforcing biobased plastics. A broader application of cellulose fibers as a filler in polymer composites is limited because of their hydrophilicity and hygroscopicity. The recent scientific literature on plasma methods for the hydrophobization of cellulose materials is reviewed and critically evaluated.

Cold plasma within a stable supercavitation bubble - A breakthrough technology for efficient inactivation of viruses in water.

Water scarcity, one of the most pressing challenges we face today, has developed for many reasons, including the increasing number of waterborne pollutants that affect the safety of the water environment. Waterborne human, animal and plant viruses represent huge health, environmental, and financial burden and thus it is important to efficiently inactivate them. Therefore, the main objective of this study was to construct a unique device combining plasma with supercavitation and to evaluate its efficiency for water decontamination with the emphasis on inactivation of viruses.

Loss of Oxygen Atoms on Well-Oxidized Cobalt by Heterogeneous Surface Recombination.

Calorimetry is a commonly used method in plasma characterization, but the accuracy of the method is tied to the accuracy of the recombination coefficient, which in turn depends on a number of surface effects. Surface effects also govern the kinetics in advanced methods such as atomic layer oxidation of inorganic materials and functionalization of organic materials. The flux of the reactive oxygen atoms for the controlled oxidation of such materials depends on the recombination coefficient of materials placed into the reaction chamber, which in turn depends on the surface morphology, temperature, and pressure in the processing chamber.

Germination and Growth of Plasma-Treated Maize Seeds Planted in Fields and Exposed to Realistic Environmental Conditions.

In this study, we applied an inductively coupled, radio frequency oxygen plasma to maize seeds and investigated its effects on seedling emergence, plant number at tasseling, and crop yield of maize in realistic field conditions. Maize seeds of seven different hybrids were treated over two harvest years. In addition to plasma-treated seeds, a control sample, fungicide-treated seeds, an eco-layer, and a plasma and eco-layer combination, were planted.

A Review of Recombination Coefficients of Neutral Oxygen Atoms for Various Materials.

Relevant data on heterogeneous surface recombination of neutral oxygen atoms available in the scientific literature are reviewed and discussed for various materials. The coefficients are determined by placing the samples either in non-equilibrium oxygen plasma or its afterglow. The experimental methods used to determine the coefficients are examined and categorized into calorimetry, actinometry, NO titration, laser-induced fluorescence, and various other methods and their combinations.

Mechanisms Involved in the Modification of Textiles by Non-Equilibrium Plasma Treatment.

Plasma methods are often employed for the desired wettability and soaking properties of polymeric textiles, but the exact mechanisms involved in plasma-textile interactions are yet to be discovered. This review presents the fundamentals of plasma penetration into textiles and illustrates mechanisms that lead to the appropriate surface finish of fibers inside the textile. The crucial relations are provided, and the different concepts of low-pressure and atmospheric-pressure discharges useful for the modification of textile's properties are explained.

Strategies for Improved Wettability of Polyetheretherketone (PEEK) Polymers by Non-Equilibrium Plasma Treatment.

Polyetheretherketone (PEEK) is the material of choice in several applications ranging from the automotive industry to medicine, but the surface properties are usually not adequate. A standard method for tailoring surface properties is the application of gaseous plasma. The surface finish depends enormously on the processing parameters.

Hydrophobic Recovery of Plasma-Hydrophilized Polyethylene Terephthalate Polymers.

Oxygen plasma is widely used for enhancing the wettability of numerous polymers, including polyethylene terephthalate (PET). The treatment with plasma containing oxygen will cause surface functionalization with polar functional groups, which will, in turn, improve the wettability. However, the exact mechanisms leading to the hydrophilic or even super-hydrophilic surface finish are still insufficiently explored.

Surface Modifications of Wheat Cultivar Bologna upon Treatment with Non-Equilibrium Gaseous Plasma.

Seeds of wheat cultivar Bologna were treated with a low-pressure, inductively coupled, radio frequency oxygen plasma. E-mode and H-mode plasma at the real powers of 25 and 275 W, respectively, was used at treatment times of 0.1-300 s.

Comparison of Plasma Deposition of Carbon Nanomaterials Using Various Polymer Materials as a Carbon Atom Source.

Carbon nanowalls are promising materials for various electrochemical devices due to their chemical inertness, desirable electrical conductivity, and excellent surface-to-mass ratio. Standard techniques, often based on plasma-assisted deposition using gaseous precursors, enable the synthesis of top-quality carbon nanowalls, but require long deposition times which represents a serious obstacle for mass applications. Here, an alternative deposition technique is presented.

Rapid Functionalization of Polytetrafluorethylene (PTFE) Surfaces with Nitrogen Functional Groups.

The biocompatibility of body implants made from polytetrafluoroethylene (PTFE) is inadequate; therefore, the surface should be grafted with biocompatible molecules. Because PTFE is an inert polymer, the adhesion of the biocompatible film may not be appropriate. Therefore, the PFTE surface should be modified to enable better adhesion, preferably by functionalization with amino groups.

Contact transmission of SARS-CoV-2 on fomite surfaces: surface survival and risk reduction.

There is an unprecedented concern regarding the viral strain SARS-CoV-2 and especially its respiratory disease more commonly known as COVID-19. SARS-CoV-2 virus has the ability to survive on different surfaces for extended periods, ranging from days up to months. The new infectious properties of SARS-CoV-2 vary depending on the properties of fomite surfaces.