Non-thermal Plasma Technique Research Articles

Dynamic of mode transition in air surface micro-discharge plasma: reactive species in confined space

Abstract Flexible surface micro-discharge plasma is a non-thermal plasma technique used for treating wounds in a painless way, with significant efficacy for chronic or hard-to-heal wounds. In this study, a confined space was designed to simulate wound conditions, gelatin was used to simulate wound tissue. The distinctions between open and confined spaces were explored, and the effects of temperature, humidity, discharge power, and the gap size within the confined space on the plasma characteristics were analyzed. It was found that, temperature, humidity and discharge power are important factors that affect the concentration distribution of active components and the mode transition between ozone and nitrogen oxides. Compared to open space, the concentration of ozone in confined space was relatively lower, which facilitated the formation of nitrogen oxides. In open space, the discharge was dominated by ozone initially. As temperature, humidity and discharge power increased, nitrogen oxides in the gas-phase products were gradually detected. In confined space, nitrogen oxides can be detected at an early stage and at much higher concentrations than ozone concentration. Furthermore, as the gap of the confined space decreased, the concentration of ozone was observed to decrease while that of nitrate increased, and the rate of this concentration change was further accelerated at higher temperature and higher power. It was shown that ozone concentration decreased from 0.11 µmol to 0.03 µmol and the nitrate concentration increased from 20.5 µmol to 24.5 µmol when the spacing in the confined space was reduced from 5 mm to 1 mm, the temperature of the external discharge was controlled at 40 °C, and the discharge power was 12 W. In summary, this work reveals the formation and transformation mechanisms of active substances in air surface micro-discharge plasma within confined space, providing foundational data for its medical applications.

Facile fabrication of ZnO nanoparticles via non-thermal plasma technique and their anti-corrosive effects on X60 API 5L steel in 1M HCl solution

This work aims to explore the efficiency of ZnO nanoparticles synthesized via the non-thermal gliding arc discharge-assisted plasma (NT-GAD) technique for inhibiting the corrosion of X60 API 5L steel in a 1M HCl environment. The XRD pattern revealed that the ZnO nanoparticles exhibit hexagonal wurtzite structure with average particle size of ∼24 nm. UV–visible spectroscopy analysis revealed an absorption peak centering at 365 nm, corresponding to an energy band gap of 3.29 eV. SEM and TEM analysis revealed that the nanoparticles exhibit an agglomerated and irregular morphology. The corrosion inhibition of ZnO NPs was investigated via the electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests (PDP), while varying both concentration and temperature. The results revealed that the increase in inhibitor concentration resulted in a higher activity at ambient temperature, with an optimal efficiency of 93 % at a concentration of 100 mg/L. However, the increase in temperature remarkably reduced the inhibition efficiency, suggesting a physisorption behavior of ZnO NPs onto the steel surface. AFM and FE-SEM analysis confirmed the formation of a protective layer on the X60 API 5L steel surface. This study emphasizes the significant potential of ZnO NPs synthesized via the NT-GAD assisted plasma technique as corrosion inhibitor for X60 API 5L carbon steel in 1M HCl corrosive media.

Plasma-catalytic synergistic oxidation of NO in the non-thermal plasma system: Insight into the active sites effect

Superoxide radicals-dominated oxidation plays a crucial role in the removal of NOx in gas treatment schemes, especially in the catalytic oxidation of NO at room temperature. However, the specific mechanism underlying radical oxidation processes remains unclear. In this study, a series of transitional metal (Mn, Co, Cr) catalysts anchored on graphitic carbon nitride (g-C3N4) were prepared and then introduced into non-thermal plasma (NTP) system to produce highly reactive superoxide free radicals (•O2-) for deep oxidation of NO. Experimental results revealed that the optimized CrCN catalyst, in combination with the NTP technique, exhibited an impressive oxidation efficiency of up to 100 %, which was 10 % and 30 % higher than that of MnCN and CoCN, respectively. Moreover, it was 1.56 times higher than that of NTP alone, indicating a synergistic effect of the NTP system and catalysis. The characterization results demonstrated that CrCN catalyst, with higher specific surface area and smaller grain sizes, was beneficial to increase the chemisorbed oxygen content and produce superoxide free radicals, which were proved by XPS, ESR technologies. Furthermore, the possible catalytic mechanism was proposed, which provided a basis for further understanding of the catalytic oxidation activity.

Degradation of perfluoroalkyl and polyfluoroalkyl substances (PFAS) in water by use of a nonthermal plasma-ozonation cascade reactor: Role of different processes and reactive species

The widespread use of perfluoroalkyl and polyfluoroalkyl substances (PFAS) in the last century has caused serious pollution of water bodies around the world, threatening the health of humans and other organisms. In this work, a novel cascade reactor configuration, comprised of a dielectric barrier discharge (DBD) plasma chamber connected with an ozonation chamber was used to treat municipal secondary effluent loaded with several PFAS. The electrical energy per order (EE/O) for degradation of perfluorooctanoic acid (PFOA) and perfluorodecanoic acid (PFDA) amounts 180 and 100 kWh/m3, respectively. While the short-chain PFAS (perfluorobutanoic acid (PFBA), perfluorohexanoic acid (PFHxA)) were difficult to be degraded, i.e. degradation percentage < 32 % after 60 min, 80–90 % of the longer PFAS (PFOA and PFDA) were degraded within 60 min. The degradation of PFAS mainly occurred in the plasma chamber rather than in ozonation chamber. This is because that reductive species produced in plasma chamber, such as hydrated electrons (eaq−) and Ar+, played a direct role in defluorination, while oxidative species, including OH, O, O2−, 1O2, O3, and H2O2, has a very limited contribution for defluorination. Enhancing the utilization of reductive species is crucial to degrade PFAS. Perfluoroalkyl carboxylic acids (PFCA) generated during the plasma reactions may have a potential risk for environment. As such, further optimization should focus on full mineralization. This study provides an approach to solve the problem of PFAS-contaminated wastewater, which is of the importance to promote the application of nonthermal plasma technique in water treatment.

Synthesis of Zinc Oxide Nanoflakes by Non-Thermal Plasma Technique and Evaluation of Anticancer Activity in Vitro

This paper describes the synthesis of ZnO nanoparticles using air microplasma jets as the main reaction medium. Various techniques, including X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and UV—Vis spectroscopy, were employed to confirm the characterization of the artificially synthesized ZnO nanoparticles. The absence of additional peaks associated with secondary phases of ZnO, as revealed by the XRD analysis, indicates the exceptional purity of these nanoparticles. Through the use of SEM, we examined the surface morphology and observed a substantial rate of agglomeration. The energy band gaps of ZnO nanoparticles were determined to be 3.3 electron volts (eV). The cytotoxic effects of zinc oxide nanoparticles were assessed using the methyl thiazolyl tetrazolium (MTT) assay on breast cancer cells exposed to various doses of the nanoparticles. The Acridine-Orange/Ethidium-bromide (AO/EB) dual stain was employed to assess apoptotic cells. The data indicate that ZnO NPs can induce apoptosis, suggesting their potential as an anticancer treatment in breast cancer cell lines. The presented findings indicate that nanoscale zinc oxide particles (ZnO NPs) possess significant potential for future utilization in many biological applications. An example of such an application could be the prospective substitution for chemotherapy in the management of various forms of cancer diseases.

Toll-like receptor-immobilized carbon paste electrodes with plasma functionalized amine termination: Towards real-time electrochemical based triaging of gram-negative bacteria

Chronic wounds caused due to bacterial biofilms are detrimental to a patient, and an immediate diagnosis of these bacteria can aid in an effective treatment, which is still an unmet clinical need. An instant and accurate identification of bacterial type could be made by utilizing the Toll-Like Receptors (TLRs) combined with Myeloid Differentiation factor 2 (MD-2). Given this, we have developed an electrochemical sensing platform to identify the gram-negative (gram-ve) bacteria using TLR4/MD-2 complex. The nonthermal plasma (NTP) technique was utilized to functionalize amine groups onto the carbon surface to fabricate cost-effective carbon paste working electrodes (CPEs). The proposed electrochemical sensor platform with a specially engineered electrochemical cell (E-Cell) identified the Escherichia coli (E. coli) in a wide linear range of 1.5×10° - 1.5×106 C.F.U./mL, accounting for a very low detection limit of 0.087 C.F.U./mL. The novel and cost-effective sensor platform identified gram-ve bacteria predominantly in a mixture of gram positive (gram+ve) bacteria and fungi. Further, towards real-time detection of bacteria and point-of-care (PoC) applications, the effect of the pond water matrix was studied, which was minimal, and the sensor could identify E. coli concentrations selectively, showing the potential application of the proposed platform towards real-time bacterial detection.

Selected Materials and Technologies for Electrical Energy Sector

Ensuring the energy transition in order to decrease CO2 and volatile organic compounds emissions and improve the efficiency of energy processes requires the development of advanced materials and technologies for the electrical energy sector. The article reviews superconducting materials, functional nanomaterials used in the power industry mainly due to their magnetic, electrical, optical, and dielectric properties and the thin layers of amorphous carbon nitride, which properties make them an important material from the point of view of environmental protection, optoelectronic, photovoltaic and energy storage. The superconductivity-based technologies, material processing, and thermal and nonthermal plasma generation have been reviewed as technologies that can be a solution to chosen problems in the electrical energy sector and environment. The study explains directly both—the basics and application potential of low and high-temperature superconductors as well as peculiarities of the related manufacturing technologies for Roebel cables, 1G and 2G HTS tapes, and superconductor coil systems. Among the superconducting materials, particular attention was paid to the magnesium di-boride MgB2 and its potential applications in the power industry. The benefits of the use of carbon films with amorphous structures in electronics, sensing technologies, solar cells, FETs, and memory devices were discussed. The article provides the information about most interesting, from the R&amp;D point of view, groups of materials for PV applications. It summarises the advantages and disadvantages of their use regarding commercial requirements such as efficiency, lifetime, light absorption, impact on the environment, costs of production, and weather dependency. Silicon processing, inkjet printing, vacuum deposition, and evaporation technologies that allow obtaining improved and strengthened materials for solar cell manufacturing are also described. In the case of the widely developed plasma generation field, waste-to-hydrogen technology including both thermal and non-thermal plasma techniques has been discussed. The review aims to draw attention to the problems faced by the modern power industry and to encourage research in this area because many of these problems can only be solved within the framework of interdisciplinary and international cooperation.

Supported bimetallic hydrogenation catalysts treated by non-thermal plasmas

Non-thermal plasma (NTP) may be an effective and clean way for enhancing catalyst performance. The paper aims to treat the surface of catalysts by different NTP techniques. Here, radio-frequency (RF) plasma jet, dielectric barrier discharge (DBD), and spark discharge are used to treat supported bimetallic hydrogenation catalysts (i.e., Mo-Ni sulfide/γ-Al2O3 and Mo-Co oxide/γ-Al2O3) in ambient air. Surface representations of the virgin and NTPs treated catalysts show that the surface morphology, chemical states and functional groups change remarkably after NTPs treatment. The catalyst’s surface become smoother after RF plasma jet treatment, but rougher after DBD or spark discharge treatment, compared with the virgin case. The heavy particles (i.e., Ar metastable states) in RF plasma jet, high-energy electrons in DBD, and heat in spark discharge play major roles in the plasma-catalyst interactions, respectively. The evident promotion of Mo chemical valence by the oxidation of O atoms happens after DBD treatment, which indicates that DBD may be an effective way to regulate Mo chemical valence. The MoS2 layers of the Mo-Ni sulfide/γ-Al2O3 catalyst are severely destroyed as the MoS2 Raman spectrum disappear after RF plasma jet treatment. The paper provides guidance for structure regulation of catalyst surfaces by NTPs.

Plasma-synthesized platinum single atom and nanoparticle catalysts for high-current–density hydrogen evolution

“Green hydrogen” is the production of hydrogen through the electrolysis of water with renewable energy, which is an ideal form of hydrogen energy generation with zero carbon emissions. Platinum (Pt)-based catalysts have the highest catalytic efficiencies, but their application is limited by the high price and low reserves of Pt. Therefore, developing high-performance catalysts with low platinum loadings is a desirable way to reduce the cost of hydrogen production. Single atom platinum can achieve 100 % atomic utilization, but does not perform well at high current density. Here, we synthesized a catalyst composed of platinum single atoms and nanoparticles by nonthermal plasma technique. The catalyst exhibits an overpotential of 18, 89 and 130 mV at a current density of 10, 300 and 1000 mA cm−2, respectively. This performance far exceeds that of the commercial 20 wt% Pt/C and the loading is only one tenth (1.89 wt%). Nonthermal plasma technique offers an effective means to promote the synthesis of high-current hydrogen evolution reaction (HER) catalysts with low costs and the development of their industrialization.

Role of Non-Thermal Plasma in Fusarium Inactivation and Mycotoxin Decontamination.

Fusarium spp. is a well-studied pathogen with the potential to infect cereals and reduce the yield to maximum if left unchecked. For decades, different control treatments have been tested against different Fusarium spp. and for reducing the mycotoxins they produce and are well documented. Some treatments also involved integrated pest management (IPM) strategies against Fusarium spp. control and mycotoxin degradation produced by them. In this review article, we compiled different control strategies against different Fusarium spp. In addition, special focus is given to the non-thermal plasma (NTP) technique used against Fusarium spp. inactivation. In a separate group, we compiled the literature about the use of NTP in the decontamination of mycotoxins produced by Fusarium spp., and highlighted the possible mechanisms of mycotoxin degradation by NTP. In this review, we concluded that although NTP is an effective treatment, it is a nice area and needs further research. The possibility of a prospective novel IPM strategy against Fusarium spp. is also proposed.

Decontamination potential of date palm fruit via non-thermal plasma technique

The potential of the surface dielectric barrier discharge technique (SDBD) was evaluated to decontaminate the date palm fruit. Preliminary investigations emphasized that Aspergillus niger fungus was predominant in most date samples as a post-harvest infestation. The influence of SDBD techniques on the viability of A. niger isolated from date varieties was investigated and documented. Physical and chemical characterizations of treated dates were assessed, and statistical correlation coefficients were calculated and elucidated. A 4 log10 reduction of A. niger radial growth was observed at 3 min exposure/15 days of incubation. Simultaneous reductions in pH, water activity, and moisture content of treated dates were observed when compared to untreated dates. Statistical analysis showed a positive correlation between physical and chemical variables with the viability of A. niger in treated samples. Therefore, we believe that SDBD treatment will be a promising technique for decontaminating date fruits from attacked fungi, which will positively impact sustainable food security and consumer health.

Toward Ideal VOCs and Nanoparticle Emission Control Technology Using a Wet-Type Catalysis Nonthermal Plasma Reactor

Several exhaust gas regulations are being implemented to prevent the hazardous emissions of volatile organic compounds (VOCs) and particulate matter (PM) from paint and print factories. The VOCs generate photochemical oxidants and suspended PM, such as PM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2.5</sub> , which has become a global environmental problem. We evaluate the catalytic nonthermal plasma (NTP) technique for controlling the emission of VOCs. The article proposes a wet-type catalysis plasma reactor to extend the treatment of water-soluble VOCs. Initial evaluation of the proposed technique involves simultaneous removal of nanoparticles along with individual VOCs, toluene, acetaldehyde, acetic acid, and ammonia, at a relatively high gas flow rate of 10 L/min. Further, pellets of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">α</i> -alumina and TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> spheres are employed in the NTP reactors for assessing their catalytic performance. We install an MnO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> catalytic reactor downstream of the plasma reactor for ozone removal. Simultaneous treatment of typical VOCs and nanoparticles using dry and wet-type catalytic NTP reactors shows that the wet-type reactor has superior average particle collection efficiency of 100%. However, the dry-type NTP with <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">α</i> -alumina shows a higher toluene removal efficiency of 91% compared to 73% in the wet type. Further, the respective removal efficiencies for acetaldehyde, acetic acid, and ammonia are 100%, 100%, and 95%. Notably, the toluene removal efficiency drops to 65% with the TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> catalyst.

Nonthermal Plasma Treatment for Electrocatalysts Structural and Surface Engineering

Structure and surface modification of electrocatalysts demonstrates a promising lead for achieving excellent electrocatalytic activity and efficiency. Among various surface modification strategies, nonthermal plasma technique possesses an irreplaceable role due to the merits of simple but controllable operation procedure, low pollution, low cost, and easy scale‐up for practical applications. Nonthermal plasma treatment, as a powerful tool for material surface and structural engineering, can mainly benefit the electrocatalytic reactions in the following aspects: surface atom doping or reconstructing, introducing vacancies or defects, surface partially reducing or oxidizing, and increasing the porosity or roughness. Given to its flexibility, plasma modification is gaining a noticeable popularity, and great progress has been made in applying plasma for optimizing surface properties of the mainstream electrocatalysts, including metal‐free carbon materials, metal oxides, and other compounds, as well as organometallic electrocatalysts, etc. This review first summarizes the recent advances in nonthermal plasma modification for achieving desirable electrocatalytic behaviors, aiming to highlight the cutting‐edge function designs of electrocatalysts with plasma technology. It is hoped that this work can give some inspiration for the development of highly efficient electrocatalysts.

Plasma assists titanium nitride and surface modified titanium nitride nanoparticles from titanium scraps for magnetic properties and supercapacitor applications

Plasma methods are efficient processing for metal recovery from metal scrap, bearing minerals, electronic waste, etc. In this work, pure titanium nitride nanoparticles (TiN NPs) were synthesized from titanium scraps by the thermal plasma arc discharge (TPAD) method. TPAD synthesized TiN NPs have a highly crystalline nature with cubic and spherical morphologies with average particle sizes of 30–100 nm. Further, prepared TiN NPs involving surface modification (SM) or etching processes were investigated by using the non-thermal DC glow discharge plasma technique with air atmosphere at different processing times. SM@TiN NPs have a comparatively low crystalline, which was confirmed from the powder X-ray diffraction technique. SM@TiN NPs have very interesting core shell morphologies, which are due to the surface interactions of ionized air molecules. TiN and SM@TiN NPs have room-temperature ferromagnetic properties with high saturation magnetization (Ms) up to 2.6 and 3.0 emu/g and very high coercivity (Hc) of 235.5 Oe, respectively. TiN and SM@TiN NPs have superior energy storage performance with an outstanding specific capacitance of 192.8 and 435.1 F/g at a current density of 2 A/g with pseudocapacitive behavior. These results reveal that TiN and SM@TiN NPs have highly promising electrodes for supercapacitor applications.

Non-thermal plasma technique for preservation of fresh foods: A review

Fruits and vegetables, as fresh foods, are significant sources of nutrients. However, the spread of diseases related to fresh foods is widespread. Development and research of rotting-control technologies are necessary to maintain quality, reduce postharvest biological hazards, while processing and storage are essential to increase their shelf-life. Cold plasma as an advanced non-thermal disinfection method can be supplementary or sole alternative for reducing microbial loads on raw or fresh products and packaging materials. Plasma employs inert gases at room temperature to generate ionized and highly reactive, e.g., positive and negative ions, electrons, molecules in (non) excited states, free radicals, and photons. Different plasma species react with the biological cells, fostering permanent changes at the molecular levels and morphology, thus leading to their inactivation. There are three primary mechanisms attributed to cell death by plasma, including cell surface etching induced by reactive species, impact on intracellular components, and the destruction of genetic material. Aside from that, plasma-mediated treatments are beneficial enzymatic inactivation, resulting in a shelf-life extension. Food processors can employ this technology for surface decontamination and impediment for biofilm development. Cold plasma may induce bioactive compounds degradation by the combined effects of numerous plasma-reactive species and thermal-induced oxidative cleavage pathways. Therefore, issues related to this technology include adverse effects on food components, especially lipids and vitamins, still require more investigations to improve the practical applicability of this technique.

Spectroscopic characterization of soil dissolved organic matter during dielectric barrier discharge (DBD) plasma treatment: Effects of discharge power, atmosphere and soil moisture content

Non-thermal plasma (NTP) technology is an emerging advanced oxidation process, which has shown excellent performances in soil organic pollution remediation. Dissolved organic matter (DOM) is one of the most important components in soil, however, investigations on the structural and compositional changes of DOM during NTP process are lacking. Therefore, in the present study, we systematically investigated the soil DOM changes under different discharge voltages, atmospheres or soils with different moisture contents. The results indicated that after NTP treatment, substantial soil organic matters were released and dissolved in water. For instance, the DOC value of DOM increased dramatically from 21.1 to 197.3 mg L−1 after being discharged for 120 min under the discharge voltage of 80 V. The UV–Vis characterization results indicated the significant increase of hydrophilicity, and decreases of aromaticity and molecular weight for soil DOM during the initial discharge period. However, long time discharge resulted in slight recovery of aromaticity and hydrophobicity, possibly due to the dehydration and re-condensation of small molecules. EEM-FRI results indicated that the total fluorescence intensity of DOM decreased obviously, indicating the destruction of fluorescent dissolved organic matter (FDOM). While the proportions of humic-like and microbial byproduct-like substances increased, indicating that those substances were more recalcitrant under NTP treatment compared with fulvic acid-like and aromatic protein-like substances. Four fluorescence components were identified by PARAFAC, and microbial and terrestrial humic-like substances were more difficult to degrade compared to other humic-like substances and fulvic acid-like substances. Additionally, discharge voltage and atmosphere had great influences on DOM changes, while the impact of soil moisture content was not significant. Overall, this study provided insights into the DOM changes during NTP process, which is valuable for more comprehensive evaluation of the NTP technique application in practical soil remediation.

Insight into Nanoparticle-Number-Derived Characteristics of Precharged Biodiesel Exhaust Gas in Nonthermal Plasma State.

The utilization of biodiesel as an alternative partial replacement of diesel fuel was shown to improve exhaust emissions from diesel engines. Waste cooking oil biodiesel (WCO) has also gained more attention due to edible biofuel supply and the environment. In this study, a nonthermal plasma (NTP) technique was applied to be equipped into the after-treatment system of a four-cylinder diesel engine at medium- and high-load conditions. The exhaust gases in the NTP state from the combustion of WCO and diesel (D100) fuels were partially drawn by spectrometers and nanoparticle-number-derived characteristics were analyzed. The particle number, area, and mass concentrations were in log-normal distribution over equivalent diameters, and they were higher at high load. The concentration of the particulate matter (PM) was lower but was larger in size when the NTP charger was activated due to coagulation principally owing to WCO’s number and surface area. The total particle masses were lower for WCO at the two load conditions tested. During NTP charger activation, the mass mean diameters were increased by maximum values of 24.0% for D100 and 5.5% for WCO. The PM removal efficiencies were maximized by 10.8% for D100 and 16.7% for WCO when the NTP charger was in use, and the WCO exhaust was dominantly seen to simultaneously reduce NOx and PM emissions.

Aluminum surface nitriding by an atmospheric-pressure non-thermal plasma technique

The application of aluminum is often limited by poor hardness, and plasma nitriding can make it have excellent mechanical properties. The purpose of this study is to nitride the aluminum surface by non-thermal transferred arc plasma technology. During the plasma nitriding process, the maximum effective value of output current is about 390 mA and the overall temperature of the samples is much lower than the solidus temperature. It is found that the microstructure and mechanical properties of the aluminum surface are improved by adding hydrogen into the nitrogen plasma. Compared with the surface treated by pure N2 plasma, the particle size of the aluminum surface treated by N2/H2 plasma is smaller. The surface hardness of aluminum is nearly doubled after being treated in 6.0 vol% H2 + 94.0 vol% N2 atmosphere.

Efficient Nitrogen Fixation to Ammonia through Integration of Plasma Oxidation with Electrocatalytic Reduction.

Present one-step N2 fixation is impeded by tough activation of the N≡N bond and low selectivity to NH3 . Here we report fixation of N2 -to-NH3 can be decoupled to a two-step process with one problem effectively solved in each step, including: 1) facile activation of N2 to NOx - by a non-thermal plasma technique, and 2) highly selective conversion of NOx - to NH3 by electrocatalytic reduction. Importantly, this process uses air and water as low-cost raw materials for scalable ammonia production under ambient conditions. For NOx - reduction to NH3 , we present a surface boron-rich core-shell nickel boride electrocatalyst. The surface boron-rich feature is the key to boosting activity, selectivity, and stability via enhanced NOx - adsorption, and suppression of hydrogen evolution and surface Ni oxidation. A significant ammonia production of 198.3 μmol cm-2 h-1 was achieved, together with nearly 100 % Faradaic efficiency.

Experimental study on plasma denitration by a bamboo based composite catalyst

In this work, the NO removal activity by non-thermal plasma (NTP) using a new bamboo-based catalyst has been investigated at ambient temperature. The new catalyst was prepared by a facile solvent-thermal method. It was shown that after the introduction of Oxygen vacancies (OVs), the NO removal efficiency was increased from 31.5% (BC(Bi)) to 47.03% (BC(Bi)-OVs). The efficiency was further increased to 73.81% after combined with the NTP technique, which is 2.34 and 1.57 times higher than that of the BC(Bi) and BC(Bi)-OVs, respectively. The synergistic effect of OVs and NTP was studied by SEM, XPS, XRD, PL, and UV–Vis DRS analysis. This study provides a new idea for better understanding the NTP process and improving the plasma NO removal efficiency.