Nitrogen Oxide Species Research Articles

Recent Progress in the Electrochemical Formation of C-N Bonds for Construction of Organic Compounds via the Use of NOx/NOx.

Emissions of nitrogen oxide (NOx) species (NO and NO2) and nitrate/nitrite NOx-, such as NO3- and NO2-, have led to serious water pollution and climate challenges. How to remove these wastes is a global problem that urgently needs to be addressed. As reported, electrochemical catalytic technology under ambient conditions is of great interest for NOx/NOx- removal. Additionally, the in situ utilization of surface-adsorbed nucleophilic intermediates generated from the electrochemical reduction of NOx/NOx- can provide a sustainable strategy for building C-N bonds, upgrading waste NOx/NOx- into value-added organic products, such as amines, oximes, amides, and amino acids, while remediating the environment. This review summarizes the most recent progress in the construction of nitrogen compounds by coupling electrochemical NOx/NOx- reduction reactions with inorganic/organic substrates, focuses on understanding the adsorption-transformation mechanism during the NOx/NOx- reduction process, and discusses multiple side reactions and complex pathways. Important strategies, such as coupled system development and catalyst preparation, are also presented to broaden the range of nitrogen compounds and improve yields. Finally, a few key challenges and future research directions for the development of efficient and low-cost electrochemical C-N coupling processes are discussed.

Synergistic Pore Structure and Active Site Modulation in Co-N-C Catalysts Enabling Stable Zinc-Air Batteries.

Development of cheap, highly active, and durable nonprecious metal-based oxygen electrocatalysts is essential for metal-air battery technology, but achieving the balance of oxygen evolution reaction (OER)/oxygen reduction reaction (ORR) bifunctional performance and long-term durability is still a great challenge. Using a typical Co-N-C catalyst as a model, herein, we introduced ammonium chloride into nitrogen-doped carbon materials containing metal elements during the pyrolysis process (Co-N-C/AC), which not only increases the active area but also realizes the accurate customization of the active site (pyridine nitrogen and cobalt oxide species) so as to achieve the balance of the OER/ORR bifunctional sites. The synthesized Co-N-C/AC bifunctional catalyst with a three-dimensional porous structure exhibits a smaller potential gap of 0.72 V. The peak power density of the aqueous cell at a current density of 308 mA cm-2 is 203 mW cm-2. The cycle life (≈3900 h) is longer than those of other recently reported aqueous Zn-air batteries (ZABs). The peak power density of the Co-N-C/AC-based quasi-solid-state ZAB reaches 550 mW cm-2 for ∼72 h. This work shows a feasible path for the practical application of ZABs by balancing the bifunctional electrocatalysts by tailoring the active site reasonably.

Emerging Role of p‐Block Element in Catalyzing Electrochemical NOx Reduction to Ammonia: A Theoretical Perspective

AbstractFixing earth‐abundant nitrogen elements into essential compounds is one of the ultimate issues for mankind. Electrochemical nitrogen fixation is regarded as promising to replace the Haber‐Bosch (HB) process at current stage. However, direct fixation of N2 is found skeptical recently due to the stable chemical properties of N2 molecule. In this regard, the more reactive nitrogen oxides (NOx) species came to light as an alternative of nitrogen sources. Since NOx species is one of the most prevalent pollutants in wastewater, it is also desired that NOx reduction can transform these detrimental ingredients into value‐added products such as ammonia. Like other chemical reactions, the performance of electrochemical NOx reduction to ammonia (eNOxRA) has a strong relation with the performance of catalysts. Previously, catalyst design of eNOxRA is dominantly based on transition metals. The role of p‐block elements in eNOxRA is not fully realized until very recent years. In this perspective, the up‐to‐date advances of p‐block‐contained catalysts in eNOxRA are concluded, with the role of p‐block elements specifically classified and discussed. Several strategies are also introduced to delicately investigate the interaction between p‐block elements and NOx species. At the end, some dilemmas and potential opportunities are proposed to achieve a more comprehensive understanding toward developing high‐efficient p‐block electrocatalyst for NOxRA.

The effect of carbonized zeolitic imidazolate framework-67 (ZIF-67) support on the reactivity and selectivity of bimetal-catalytic aqueous NO3− reduction

A metallic catalyst, Cobalt N-doped Carbon (Co@NC), was obtained from Zeolitic-Imidazolate Framework-67 (ZIF-67) for efficient aqueous nitrate (NO3−) removal. This advanced catalyst indicated remarkable efficiency by generating valuable ammonium (NH3/NH4+) via an environmentally friendly production technique during the nitrate treatment. Among various metals (Cu, Pt, Pd, Sn, Ru, and Ni), 3.6%Pt–Co@NC exhibited an exceptional nitrate removal, demonstrating a complete removal of 60 mg/L NO3−-N (265 mg/L NO3−) in 30 min with the fastest removal kinetics (11.4 × 10−2 min−1) and 99.5% NH4+ selectivity. The synergistic effect of bimetallic Pt–Co@NC led to 100% aqueous NO3− removal, outperforming the reactivity by bare ZIF-67 (3.67%). The XPS analysis illustrated Co's promotor role for NO3− reduction to less oxidized nitrogen species and Pt's hydrogenation role for further reduction to NH4+. The durability test revealed a slight decrease in NO3− removal, which started from the third cycle (95%) and slowly proceeded to the sixth cycle (80.2%), while NH4+ selectivity exceeded 82% with no notable Co or Pt leaching throughout seven consecutive cycles. This research shed light on the significance of the impregnated Pt metal and Co exposed on the Co@NC surface for the catalytic nitrate treatment, leading to a sustainable approach for the effective removal of nitrate and economical NH4+ production.

Descriptor‐Based Volcano Relations Predict Single Atoms for Hydroxylamine Electrosynthesis

AbstractHydroxylamine (NH2OH) is an important feedstock in fuels, pharmaceuticals, and agrochemicals. Nanostructured electrocatalysts drive green electrosynthesis of hydroxylamine from nitrogen oxide species in water. However, current electrocatalysts still suffer from low selectivity and manpower‐consuming trial‐and‐error modes, leaving unclear selectivity/activity origins and a lack of catalyst design principles. Herein, we theoretically analyze key determinants of selectivity/activity and propose the adsorption energy of NHO (Gad(*NHO)) as a performance descriptor. A weak *NH2OH binding affinity and a favorable reaction pathway (*NHO pathway) jointly enable single‐atom catalysts (SACs) with superior NH2OH selectivity. Then, an activity volcano plot of Gad(*NHO) is established to predict a series of SACs and discover Mn SACs as optimal electrocatalysts that exhibit pH‐dependent activity. These theoretical prediction results are also confirmed by experimental results, rationalizing our Gad(*NHO) descriptor. Furthermore, Mn−Co geminal‐atom catalysts (GACs) are predicted to optimize Gad(*NHO) and are experimentally proved to enhance NH2OH formation.

Descriptor-Based Volcano Relations Predict Single Atoms for Hydroxylamine Electrosynthesis.

Hydroxylamine (NH2OH) is an important feedstock in fuels, pharmaceuticals, and agrochemicals. Nanostructured electrocatalysts drive green electrosynthesis of hydroxylamine from nitrogen oxide species in water. However, current electrocatalysts still suffer from low selectivity and manpower-consuming trial-and-error modes, leaving unclear selectivity/activity origins and a lack of catalyst design principles. Herein, we theoretically analyze key determinants of selectivity/activity and propose the adsorption energy of NHO (Gad(*NHO)) as a performance descriptor. A weak *NH2OH binding affinity and a favorable reaction pathway (*NHO pathway) jointly enable single-atom catalysts (SACs) with superior NH2OH selectivity. Then, an activity volcano plot of Gad(*NHO) is established to predict a series of SACs and discover Mn SACs as optimal electrocatalysts that exhibit pH-dependent activity. These theoretical prediction results are also confirmed by experimental results, rationalizing our Gad(*NHO) descriptor. Furthermore, Mn-Co geminal-atom catalysts (GACs) are predicted to optimize Gad(*NHO) and are experimentally proved to enhance NH2OH formation.

Catalytic elimination of NOx and CH3SH over synergistic reaction induced active sites

The synergistic elimination of hazardous NOx and CH3SH is of significance in various industrial production processes. However, the synergistic elimination mechanism is ambiguous and the efficient synergistic catalysts have never been reported. Herein, the synergistic reaction is originally demonstrated over CuOx modified CeO2/TiO2 catalysts via coupling with selective catalytic reduction of NOx by NH3 and catalytic oxidation of CH3SH. CuOx modification notably improves the acidity and redox ability, and promotes the absorption and oxidation of CH3SH, thus generating more CO2 rather than toxic CO and HCN by-products. Moreover, the CH3SH oxidation reaction induces the formation of SO42- on CeOx sites that contribute to NOx reduction reaction via improving the reactivity of adsorbed NH4+ species with nitrogen oxide species. This work provides insights into the synergistic catalytic elimination of NOx and CH3SH, and guides the development of environmental catalysis techniques for eliminating multiple pollutants in actual complex operating conditions.

Estimating nitric oxide (NO) from MDSCs by Griess method.

The functional importance of nitric oxide (NO) in the fields of immunology concerning its antimicrobial, anti-tumoral, anti-inflammatory, and immunosuppressive effects have made it inevitable to study its secretion from various cells. Nitrogen oxide synthase (NOS) is the enzyme responsible for synthesizing NO and its three isoforms function in a cell-dependent manner. NO is oxidized rapidly to Reactive nitrogen oxide species (RNOS) through which the roles of NO are being carried out. One of the major immune cells secreting NO is myeloid-derived suppressor cells (MDSCs). The function of these MDSCs in the suppression of T-cell proliferation as well as T-cell differentiation is found to be dependent on NO secretion. Apart from T-cell suppressive activity, NO is also known to interfere with natural killer (NK) cell functions. A convenient method to estimate NO secretion is by using Griess reagent named after Johann Peter Griess. In this method, NO reacts with the reagents to form a colored azo dye detectable using a microplate reader at a wavelength of 548nm. In this chapter, we summarized the detailed method of estimating NO from MDSCs by the Griess method.

Electrocatalytic Systems for NOx Valorization in Organonitrogen Synthesis.

Inorganic nitrogen oxide (NOx ) species, such as NO, NO2 , NO3 - , NO2 - generated from the decomposition of organic matters, volcanic eruptions and lightning activated nitrogen, play important roles in the nitrogen cycle system and exploring the origin of life. Meanwhile, excessive emission of NOx gases and residues from industry and transportation causes troubling problems to the environment and human health. How to efficiently handle these wastes is a global problem. In response to the growing demand for sustainability, scientists are actively pursuing sustainable electrochemical technologies powered by renewable energy sources and efficient utilization of hydrogen energy to convert NOx species into high-value organonitrogen chemicals. In this minireview, recent advances of electrocatalytic systems for NOx species valorization in organonitrogen synthesis are classified and described, such as amino acids, amide, urea, oximes, nitrile etc., that have been widely applied in medicine, life science and agriculture. Additionally, the current challenges including multiple side reactions and complicated paths, viable solutions along with future directions ahead in this field are also proposed. The coupling electrocatalytic systems provide a green mode for fixing nitrogen cycle bacteria and bring enlightenment to human sustainable development.

Electrocatalytic Systems for NOx Valorization in Organonitrogen Synthesis

AbstractInorganic nitrogen oxide (NOx) species, such as NO, NO2, NO3−, NO2− generated from the decomposition of organic matters, volcanic eruptions and lightning activated nitrogen, play important roles in the nitrogen cycle system and exploring the origin of life. Meanwhile, excessive emission of NOx gases and residues from industry and transportation causes troubling problems to the environment and human health. How to efficiently handle these wastes is a global problem. In response to the growing demand for sustainability, scientists are actively pursuing sustainable electrochemical technologies powered by renewable energy sources and efficient utilization of hydrogen energy to convert NOx species into high‐value organonitrogen chemicals. In this minireview, recent advances of electrocatalytic systems for NOx species valorization in organonitrogen synthesis are classified and described, such as amino acids, amide, urea, oximes, nitrile etc., that have been widely applied in medicine, life science and agriculture. Additionally, the current challenges including multiple side reactions and complicated paths, viable solutions along with future directions ahead in this field are also proposed. The coupling electrocatalytic systems provide a green mode for fixing nitrogen cycle bacteria and bring enlightenment to human sustainable development.

The methodology of decoupling fuel and thermal nitrogen oxides in multi-dimensional computational fluid dynamics combustion simulation of ammonia-hydrogen spark ignition engines

Under the paradigm of carbon neutrality, ammonia-hydrogen (NH3–H2) blended fuel presents itself as a zero-carbon alternative to petroleum-based fuels, effectively reducing carbon emissions originating from internal combustion engines. In the combustion process of conventional hydrocarbon fuels, the production of nitrogen oxides (NOX) predominantly arises from nitrogen present in the atmosphere, which occurs through the Zeldovich mechanism under high-temperature conditions. These NOX species, commonly referred to as thermal NOX, rely on inert nitrogen. However, the utilization of ammonia fuel activates the reactivity of nitrogen element, leading to the nitrogen-containing species formation, including NOX, termed as fuel NOX. Consequently, the combustion of ammonia-hydrogen fuel entails the coupling of thermally formed nitrogen oxides and fuel-derived nitrogen oxides. The generation of NOX is significantly influenced by the physicochemical environment, while the transient combustion conditions within the engine combustion chamber further complicate the process of NH3–H2 combustion and NOX formation. As a consequence, comprehensively investigating the NOX emission characteristics in NH3–H2 engines presents a considerable challenge. By decoupling fuel NOX and thermal NOX, a more profound understanding of NOX emission control strategies for ammonia-hydrogen engines can be attained. This research paper accomplishes the decoupling of fuel nitrogen elements and atmospheric nitrogen elements in three dimensional computational fluid dynamics engine combustion simulations. The results indicate that this decoupling methodology disregards the differentiation between the fuel NOX pool and the thermal NOX pool, resulting in a slight modification in NOX concentration. Nevertheless, this approach has minimal impact on the combustion process, ensuring that the NOX formation environment remains largely unchanged. Furthermore, it successfully demonstrates the spatial and temporal distribution characteristics of thermal NOX and fuel NOX, thereby furnishing an effective analytical tool for the comprehensive study of NOX emission characteristics in NH3–H2 engines.

Molecular insights: Proteomic and metabolomic dissection of plasma-induced growth and functional compound accumulation in Raphanus sativus

This study investigated the impact of plasma-activated water (PAW) on Raphanus sativus (radish) roots at the level of proteins and metabolites. PAW treatment induced the accumulation of reactive oxygen species (ROS) and nitrogen oxide species (NOx) in radish and enhanced the activities of antioxidant enzymes. Proteomic analysis resulted in the identification of 6054 proteins, including 1845 PAW-modulated proteins that were majorly associated with energy metabolism, ROS-detoxification, phytohormones signaling, and biosynthesis of glucosinolates. Subsequent metabolomics analysis identified 314 metabolites, of which 194 showed significant differences in response to PAW treatment. In particular, PAW treatment triggered the accumulation of functional compounds such as vitamin C, vitamin B5, glutathione, and glucosinolates, the well-known characteristic compounds of the Brassicaceae family. Further, integrating proteomics and metabolomics data provided novel insights into the molecular mechanism governing plasma-induced growth and the accumulation of these functional compounds in radish plants.

(Invited) Understanding Trends for Electrocatalytic and Catalytic Nitrate Reduction

Fixation of nitrogen such as for ammonia production through the Haber-Bosch process is imperative for feeding the world’s population, but is causing an imbalance in the nitrogen cycle as oxidized nitrogen species such as nitrate builds up. This build up of nitrate pollution from agricultural and industrial waste poses an immediate threat to environmental and human health. While separation of this nitrate is a method to produce clean water, it does not chemically address the issue of oxidized nitrate. In addition, it does not form nitrogen species in a valuable form. One method is to use nitrate waste as a feedstock for production of fertilizers such as ammonia or ammonium nitrate. In this work we discuss the use of electrocatalysis to convert nitrate to ammonia, where renewable electricity can be used to drive the reaction, minimizing carbon dioxide emissions from current methods to produce ammonia. In this talk we will discuss (1) trends in electrocatalytic nitrate reduction, (2) similarities and differences in electrocatalytic nitrate reduction and catalytic nitrate reduction (i.e., using molecular H2 rather than an applied potential), and (3) practical challenges in systems to commercially convert nitrate. Through the use of kinetic studies, in situ spectroscopy, microkinetic modeling, and density functional theory calculations, we show how the adsorption energetics of nitrate and hydrogen are descriptors for nitrate reduction on metals and alloy surfaces. We will discuss the importance of operando spectroscopy to understand the catalyst under reaction conditions. We will show how alloying Pt with Ru to increase the nitrate adsorption energy shows an increase in the rates of nitrate reduction at low Ru content. We will also show that the nitrate reduction rate is decreased when the Ru content is too high, because nitrate binds to the catalyst too strongly. We will compare the electrocatalytic results to thermal nitrate catalytic and show that while there are numerous similarities between electrocatalysis and thermal catalysis, there are also factors unique to electrocatalysis that impact the rate of reaction. These differences motivate a greater understanding of electrochemical steps and the effect of the applied potential, solvent, and ions. We will discuss how the best performing catalysts in batch systems translate to flow reactors more amenable to commercialized processes and other challenges in realistic nitrate streams containing potential catalyst poisons such as chlorides.

Relating Selective Electrochemical Nitrate Reduction to Electronic Structure by AP-XPS

Ammonia produced by the Haber-Bosch process fixes nitrogen by sourcing hydrogen from methane steam reforming—today’s most carbon intensive industrial process. Alternatively, ammonia can be produced electrochemically from industrial waste nitrogen sources (e.g. nitric oxides, and nitrate), sourcing protons from water and electrons as reducing agents. However, reduction of such oxidized nitrogen species involves complex reaction mechanisms where the stability of critical reaction intermediates (e.g. nitric oxide) dictates selectivity towards ammonia as a final product. Inspired by Hammer and Nørskov’s d-band theory, we utilize synchrotron-based ambient-pressure X-ray photoelectron spectroscopy (AP-XPS) to explore the adsorption affinity, and ability of a surface to dissociate, nitric oxide for a series of transition metals (Fe, Co, Ni, Cu). Nitric oxide adsorption affinity and dissociation are then linked to transition metal electronic structure and contextualized further with ex-situ electrochemical selectivity measurements and density functional theory (DFT) calculations.

GNOME: A Gaseous Nitrogen Oxide Measuring front-End for aqueous environmental materials

GNOME is a straightforward and easy to build sample handling apparatus, designed to prepare dissolved nitrogen oxide species in aqueous environmental samples. GNOME is designed to serve as a sample preparation device for downstream chemiluminescent analysis. It is based on the familiar chemistry ring stand; the major advantage scalability designed to accommodate the needs of the user. Additionally, since GNOME is constructed of discrete, snap-to-fit components, the modular design allows users to easily substitute or replace parts. Given that there are few to zero commercial equivalents, construction plans to fill this hardware gap are offered herein. The inlet can resolve down to a lower limit of at least 0.05 nmoles NOX, and is instrumentally linear to a ≥10 nmoles NOX. The approach increases sample throughput, data quality, and overall user experience, making it more efficient than the off-the-shelf commercial equivalent.

Long-term exposure to air pollution and cognitive function in older adults: a systematic review and meta-analysis

BackgroundNow more than ever before, air pollution and cognitive decline are global concerns. Credible links are now emerging between exposure to specific pollutants and cognitive decline. However, the role of specific pollutants on different cognitive domains in adults are inconclusive as the pathways to cognitive decline remain poorly understood.ObjectiveTo systematically review and meta-analyse the evidence for the association between long-term air pollution exposure and cognitive function in adults.Data sourcesWeb of Science, PubMed, Embase searched up to February 2021 with no language restrictions. Individual studies were identified from similar review articles.Eligibility criteriaStudies investigating the long-term (>3 years) associations between airborne pollutants and cognitive function in older adults (>50 years old).ResultsFrom 1996 records, 26 satisfied the inclusion criteria. The total sample size included over 2.4 million (53.8% female) subjects with ages ranging from 45 to 100 years (estimated mean age 70 years). Only 18/26 publications included both male and female subjects. Pollutants reported included particulate matter ≤2.5 µm (PM2.5); particulate matter ≤10 µm (PM10); nitrogen dioxide (NO2); nitrogen oxide species (NOx) and ozone (O3). Papers showed great variance in their study characteristics, air pollution modelling methodology and assessment of cognitive domain. Long-term exposure to increased levels of PM2.5 and NO2 were most strongly associated with increased risk of dementia. Decline in cognitive function, executive function, memory and language were most strongly associated with greater exposure to PM2.5, PM10 and NO2 to varying degrees.ConclusionAn increasing number of studies are supporting the hypothesis that greater exposure to air pollutants is associated with decline in cognitive functions.

Low Fouling Marine Coatings Based on Nitric Oxide-Releasing Polysaccharide-Based Hybrid Materials

Diethylenetriamine-modified heparin and alginates as well as unmodified polysaccharides were combined using sol–gel chemistry to construct hybrid material thin-film coatings. Due to the high density of amine groups, the hybrid material coatings are capable of binding nitric oxide when exposed to NO at elevated pressures, which were characterized by UV–Vis and ATR-FTIR spectroscopy. When exposed to aqueous environments, the hybrid material coatings showed nitrogen oxide release rates between 17 and 30 pmol·cm–2·s–1. Marine antifouling properties were tested against the marine bacterium Cobetia marina and the diatom Navicula perminuta. The diatom assays revealed a lower settlement on the nitric oxide-loaded hybrid materials compared to hybrid materials without nitrogen oxide release. All coatings readily suppressed attachment of the marine bacterium C. marina. The advantages of hybrid materials, composed purely of polysaccharides and siloxanes, are that their building blocks are environmentally friendly, biodegradable, and biocompatible. This makes them interesting candidates for environmentally benign marine protective coating applications. In particular, the binding of nitric oxide and release of nitrogen oxide species as naturally occurring signaling molecules were found to be promising mechanisms to add additional fouling inhibiting functionality to deter marine organisms from settlement.

Modeling regional nitrogen cycle in the atmosphere: Present situation and its response to the future emissions control strategy

Reactive nitrogen (Nr) cycle in the atmosphere has an important affection on terrestrial ecosystems, which has not been fully understood and its response to the future emissions control strategy is not clear. Taking the Yangtze River Delta (YRD) as an example, we explored the regional Nr cycle (emissions, concentrations, and depositions) and its source apportionment in the atmosphere in January (winter) and July (summer) 2015 and projected its changes under emissions control by 2030 using the CMAQ model. We examined the characteristics of Nr cycle and found that Nr suspends in the air mainly as NO, NO2, and NH3 gases and deposits to the earth's surface mainly as HNO3, NH3, NO3−, and NH4+. Due to the higher NOx than NH3 emissions, oxidized nitrogen (OXN) but not reduced nitrogen (RDN) is the major component in Nr concentration and deposition, especially in January. Nr concentration and deposition show an inverse correlation, with a high concentration in January and low in July but the opposite for deposition. We further apportioned the regional Nr sources for both concentration and deposition using the Integrated Source Apportionment Method (ISAM) incorporated in the CMAQ model. It shows that local emissions are the major contributors and this characteristic is more significant in concentration than deposition, for RDN than OXN species, and in July than in January. The contribution from North China (NC) is important for Nr in YRD, especially in January. In addition, we revealed the response of Nr concentration and deposition to the emission control to achieve the target of carbon peak in the year 2030. After the emission reduction, the relative responses of OXN concentration and deposition are generally about 100 % to the reduction of NOx emissions (~50 %), while the relative responses of RDN concentration are higher than 100 % and the relative responses of RDN deposition are significantly lower than 100 % to the reduction of NH3 emissions (~22 %). Consequently, RDN will become the major component in Nr deposition. The smaller reduction of RDN wet deposition than sulfur wet deposition and OXN wet deposition will raise the pH of precipitation and help alleviate the acid rain problem, especially in July.

Argon gas plasma-treated physiological solutions stimulate immunogenic cell death and eradicates immunosuppressive CD47 protein in lung carcinoma.

Cold atmospheric plasma-treated liquids (PTLs) exhibit selective toxicity toward tumor cells and are provoked by a cocktail of reactive oxygen and nitrogen species in such liquids. Compared to the gaseous phase, these reactive species are more persistent in the aqueous phase. This indirect plasma treatment method has gradually gathered interest in the discipline of plasma medicine to treat cancer. PTL's motivated effect on immunosuppressive proteins and immunogenic cell death (ICD) in solid cancer cells is still not explored. In this study, we aimed to induce immunomodulation by plasma-treated Ringer's lactate (PT-RL) and phosphate-buffered saline (PT-PBS) solutions for cancer treatment. PTLs induced minimum cytotoxicity in normal lung cells and inhibited cancer cell growth. ICD is confirmed by the enhanced expression of damage-associated molecular patterns (DAMPs). We evidenced that PTLs induce intracellular nitrogen oxide species accumulation and elevate immunogenicity in cancer cells owing to the production of pro-inflammatory cytokines, DAMPs, and reduced immunosuppressive protein CD47 expression. In addition, PTLs influenced A549cells to elevate the organelles (mitochondria and lysosomes) in macrophages. Taken together, we have developed a therapeutic approach to potentially facilitate the selection of a suitable candidate for direct clinical applications.

Influence of gold nanoparticles size for photocatalytic NO oxidation in low loading Au/TiO2 catalysts

Gold nanoparticles (AuNPs) supported on TiO2 are one of the most investigated photocatalysts, however, the positive effect of AuNPs size reduction on Au/TiO 2 activity is clear for conventional catalysis, but this relationship not strictly happens in photocatalysis. The present work investigates how small changes in the lower size range of AuNPs can affect the Au/TiO2 photoactivity in order to maximize the performance of photocatalysts with low metal loadings (<1 wt%). Precipitation–deposition methods and a speciation-controlled incipient wetness impregnation (ScIWI) method have been employed for preparing Au/TiO 2 photocatalysts that exhibited a NOx elimination capacity significantly higher than pristine TiO2. Comparing the photocatalysts, ScIWI method achieved the highest gold dispersion and Au–TiO2 contact perimeter providing the most active photocatalysts, confirming the positive effect of AuNPs size reduction in the average sizes around 2 nm. In addition, on the basis of the results obtained, it has been proposed that the adsorption of nitrogen oxides species on gold has a relevant role on the NO photooxidation process.