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H and 13C NMR spectra

H and 13C NMR spectra

This paper presents four new temperature readout approaches to luminescence nanothermometry in spectral regions of biological transparency demonstrated on Yb3+/Er3+-doped yttrium aluminum garnet nanoparticles. Under the 10 638 cm-1 excitation, down-shifting near infrared emissions (>10 000 cm-1) are identified as those originating from Yb3+ ions' 2F5/2 → 2F7/2 (∼9709 cm-1) and Er3+ ions' 4I13/2 → 4I15/2 (∼6494 cm-1) electronic transitions and used for 4 conceptually different luminescence thermometry approaches. Observed variations in luminescence parameters with temperature offered an exceptional base for studying multiparametric temperature readouts. These include the temperature-dependence of: (i) intensity ratio between emissions from Stark components of Er3+ 4I13/2 level; (ii) intensity ratio between emissions of Yb3+ (2F5/2 → 2F7/2 transition) and Er3+ (4I13/2 → 4I15/2 transition); (iii) band shift and bandwidth and (iv) lifetime of the Yb3+ emission (2F5/2 → 2F7/2 transition) with maximal sensitivities of 1% K-1, 0.8% K-1, 0.09 cm-1 K-1, 0.46% K-1 and 0.86% K-1, respectively. The multimodal temperature readout provided by this material enables its application in different luminescence thermometry setups as well as improved the reliability of the temperature sensing by the cross-validation between measurements. © 2021 The Royal Society of Chemistry.

This paper presents four new temperature readout approaches to luminescence nanothermometry in spectral regions of biological transparency demonstrated on Yb3+/Er3+-doped yttrium aluminum garnet nanoparticles. Under the 10 638 cm-1 excitation, down-shifting near infrared emissions (>10 000 cm-1) are identified as those originating from Yb3+ ions' 2F5/2 → 2F7/2 (∼9709 cm-1) and Er3+ ions' 4I13/2 → 4I15/2 (∼6494 cm-1) electronic transitions and used for 4 conceptually different luminescence thermometry approaches. Observed variations in luminescence parameters with temperature offered an exceptional base for studying multiparametric temperature readouts. These include the temperature-dependence of: (i) intensity ratio between emissions from Stark components of Er3+ 4I13/2 level; (ii) intensity ratio between emissions of Yb3+ (2F5/2 → 2F7/2 transition) and Er3+ (4I13/2 → 4I15/2 transition); (iii) band shift and bandwidth and (iv) lifetime of the Yb3+ emission (2F5/2 → 2F7/2 transition) with maximal sensitivities of 1% K-1, 0.8% K-1, 0.09 cm-1 K-1, 0.46% K-1 and 0.86% K-1, respectively. The multimodal temperature readout provided by this material enables its application in different luminescence thermometry setups as well as improved the reliability of the temperature sensing by the cross-validation between measurements. © 2021 The Royal Society of Chemistry.

The research subject of this paper was a detail physicochemical analysis of 28 honey samples from the northern part of Montenegro. The honey from Montenegro has not been previously studied in such detail. Differentiation between samples, such as honeydew honey and polyfloral honey, was based on electrical conductivity, which was higher than 0.8 mS cm-1 for honeydew honey, as was expected. Other investigated physicochemical parameters (water content, free acids, diastase activity, hydroxymethylfurfural (HMF) content and sugar content) have shown great similarity for all honey samples. The main interest of this study was the identification and quantification of phenolic compounds using ultra-high performance liquid chromatography (UHPLC) with mass spectrometry detection. The results show that honey samples are very rich in phenolic compounds, especially quercetin. Among the 31 quantified phenolic compounds, the most dominant were phenolic acids. The highlight was based on p-hydroxybenzoic acid, p-coumaric acid, caffeic acid and ferulic acid. Considering polyphenolic compounds and sugar content, a high nutritional value can be observed in all samples, with an emphasis on polyfloral honeys, as was confirmed with principal component analysis (PCA). In addition, all honey samples were tested for total phenolic content (TPC) and radical scavenging activity (RSA). The results indicate the higher antioxidant ability of honeys from Montenegro in comparison to some honey samples from other countries in the region.

The research subject of this paper was a detail physicochemical analysis of 28 honey samples from the northern part of Montenegro. The honey from Montenegro has not been previously studied in such detail. Differentiation between samples, such as honeydew honey and polyfloral honey, was based on electrical conductivity, which was higher than 0.8 mS cm-1 for honeydew honey, as was expected. Other investigated physicochemical parameters (water content, free acids, diastase activity, hydroxymethylfurfural (HMF) content and sugar content) have shown great similarity for all honey samples. The main interest of this study was the identification and quantification of phenolic compounds using ultra-high performance liquid chromatography (UHPLC) with mass spectrometry detection. The results show that honey samples are very rich in phenolic compounds, especially quercetin. Among the 31 quantified phenolic compounds, the most dominant were phenolic acids. The highlight was based on p-hydroxybenzoic acid, p-coumaric acid, caffeic acid and ferulic acid. Considering polyphenolic compounds and sugar content, a high nutritional value can be observed in all samples, with an emphasis on polyfloral honeys, as was confirmed with principal component analysis (PCA). In addition, all honey samples were tested for total phenolic content (TPC) and radical scavenging activity (RSA). The results indicate the higher antioxidant ability of honeys from Montenegro in comparison to some honey samples from other countries in the region.

The research subject of this paper was a detail physicochemical analysis of 28 honey samples from the northern part of Montenegro. The honey from Montenegro has not been previously studied in such detail. Differentiation between samples, such as honeydew honey and polyfloral honey, was based on electrical conductivity, which was higher than 0.8 mS cm-1 for honeydew honey, as was expected. Other investigated physicochemical parameters (water content, free acids, diastase activity, hydroxymethylfurfural (HMF) content and sugar content) have shown great similarity for all honey samples. The main interest of this study was the identification and quantification of phenolic compounds using ultra-high performance liquid chromatography (UHPLC) with mass spectrometry detection. The results show that honey samples are very rich in phenolic compounds, especially quercetin. Among the 31 quantified phenolic compounds, the most dominant were phenolic acids. The highlight was based on p-hydroxybenzoic acid, p-coumaric acid, caffeic acid and ferulic acid. Considering polyphenolic compounds and sugar content, a high nutritional value can be observed in all samples, with an emphasis on polyfloral honeys, as was confirmed with principal component analysis (PCA). In addition, all honey samples were tested for total phenolic content (TPC) and radical scavenging activity (RSA). The results indicate the higher antioxidant ability of honeys from Montenegro in comparison to some honey samples from other countries in the region.

Due to controversial reports concerning antibacterial activity of different graphene based materials it is very important to investigate their antibacterial action on a wide range of Gram-positive and Gram-negative bacteria. In this paper we have investigated the structure induced phototoxic antibacterial activity of four types of graphene based materials: graphene oxide (GO), graphene quantum dots (GQDs), carbon quantum dots (CQDs) and nitrogen doped carbon quantum dots (N-CQDs). Antibacterial activity was tested on 19 types of bacteria. It is found that nanometer-size CQDs and N-CQDs are the most potent agents whereas micrometer-size GO has very poor antibacterial activity. Electron paramagnetic resonance measurements confirmed photodynamic production of singlet oxygen for all types of used quantum dots. Detailed analysis has shown that N-CQDs are an excellent photodynamic antibacterial agent for treatment of bacterial infections induced by Enterobacter aerogenes (E. aerogenes), Proteus mirabilis (P. mirabilis), Staphylococcus saprophyticus (S. saprophyticus), Listeria monocytogenes (L. monocytogenes), Salmonella typhimurium (S. typhimurium) and Klebsiella pneumoniae.

Due to controversial reports concerning antibacterial activity of different graphene based materials it is very important to investigate their antibacterial action on a wide range of Gram-positive and Gram-negative bacteria. In this paper we have investigated the structure induced phototoxic antibacterial activity of four types of graphene based materials: graphene oxide (GO), graphene quantum dots (GQDs), carbon quantum dots (CQDs) and nitrogen doped carbon quantum dots (N-CQDs). Antibacterial activity was tested on 19 types of bacteria. It is found that nanometer-size CQDs and N-CQDs are the most potent agents whereas micrometer-size GO has very poor antibacterial activity. Electron paramagnetic resonance measurements confirmed photodynamic production of singlet oxygen for all types of used quantum dots. Detailed analysis has shown that N-CQDs are an excellent photodynamic antibacterial agent for treatment of bacterial infections induced by Enterobacter aerogenes (E. aerogenes), Proteus mirabilis (P. mirabilis), Staphylococcus saprophyticus (S. saprophyticus), Listeria monocytogenes (L. monocytogenes), Salmonella typhimurium (S. typhimurium) and Klebsiella pneumoniae.

Due to controversial reports concerning antibacterial activity of different graphene based materials it is very important to investigate their antibacterial action on a wide range of Gram-positive and Gram-negative bacteria. In this paper we have investigated the structure induced phototoxic antibacterial activity of four types of graphene based materials: graphene oxide (GO), graphene quantum dots (GQDs), carbon quantum dots (CQDs) and nitrogen doped carbon quantum dots (N-CQDs). Antibacterial activity was tested on 19 types of bacteria. It is found that nanometer-size CQDs and N-CQDs are the most potent agents whereas micrometer-size GO has very poor antibacterial activity. Electron paramagnetic resonance measurements confirmed photodynamic production of singlet oxygen for all types of used quantum dots. Detailed analysis has shown that N-CQDs are an excellent photodynamic antibacterial agent for treatment of bacterial infections induced by Enterobacter aerogenes (E. aerogenes), Proteus mirabilis (P. mirabilis), Staphylococcus saprophyticus (S. saprophyticus), Listeria monocytogenes (L. monocytogenes), Salmonella typhimurium (S. typhimurium) and Klebsiella pneumoniae.

Due to controversial reports concerning antibacterial activity of different graphene based materials it is very important to investigate their antibacterial action on a wide range of Gram-positive and Gram-negative bacteria. In this paper we have investigated the structure induced phototoxic antibacterial activity of four types of graphene based materials: graphene oxide (GO), graphene quantum dots (GQDs), carbon quantum dots (CQDs) and nitrogen doped carbon quantum dots (N-CQDs). Antibacterial activity was tested on 19 types of bacteria. It is found that nanometer-size CQDs and N-CQDs are the most potent agents whereas micrometer-size GO has very poor antibacterial activity. Electron paramagnetic resonance measurements confirmed photodynamic production of singlet oxygen for all types of used quantum dots. Detailed analysis has shown that N-CQDs are an excellent photodynamic antibacterial agent for treatment of bacterial infections induced by Enterobacter aerogenes (E. aerogenes), Proteus mirabilis (P. mirabilis), Staphylococcus saprophyticus (S. saprophyticus), Listeria monocytogenes (L. monocytogenes), Salmonella typhimurium (S. typhimurium) and Klebsiella pneumoniae.

Modified allergens are a safer and more efficient alternative to natural allergens for specific immunotherapy. As the modification of an allergen can diminish its immunogenicity due to the alteration of T-cell epitopes, in this paper we study the effects of a reversible chemical modification of Art v 1, the main allergen of mugwort pollen, on its allergenicity and immunogenicity. Modification of Art v 1 by cis-aconitylation into a polyanionic derivative (CAA) did not result in any significant structural alteration. However, IgE-binding epitopes on CAA were blocked, resulting in a reduced IgE-binding and basophil activation. Both proteins induced proliferation of CD3(+)CD4(+) T-cells in mugwort-allergic patients, but only unmodified allergens increased IL-4, IL-5 and IL-10 production. Rabbit and mouse anti-CAA antibodies exhibited cross-reactivity with native allergens and blocked human IgE-binding to Art v 1. Degradation of CAA by lysosomal fraction enzymes resulted in a similar set of peptides, harboring MHC class II-binding peptides, as unmodified proteins. Thus, cis-aconitylation modified Art v 1 had a significantly reduced allergenicity, whereas its immunogenicity was completely preserved. Acid-environment-responsive modification, which releases a full repertoire of native allergen epitopes within a particular site, can be considered a smart drug delivery system, which is able to deliver a therapeutically-effective dose in a controlled manner, and minimizes adverse side effects.

Modified allergens are a safer and more efficient alternative to natural allergens for specific immunotherapy. As the modification of an allergen can diminish its immunogenicity due to the alteration of T-cell epitopes, in this paper we study the effects of a reversible chemical modification of Art v 1, the main allergen of mugwort pollen, on its allergenicity and immunogenicity. Modification of Art v 1 by cis-aconitylation into a polyanionic derivative (CAA) did not result in any significant structural alteration. However, IgE-binding epitopes on CAA were blocked, resulting in a reduced IgE-binding and basophil activation. Both proteins induced proliferation of CD3(+)CD4(+) T-cells in mugwort-allergic patients, but only unmodified allergens increased IL-4, IL-5 and IL-10 production. Rabbit and mouse anti-CAA antibodies exhibited cross-reactivity with native allergens and blocked human IgE-binding to Art v 1. Degradation of CAA by lysosomal fraction enzymes resulted in a similar set of peptides, harboring MHC class II-binding peptides, as unmodified proteins. Thus, cis-aconitylation modified Art v 1 had a significantly reduced allergenicity, whereas its immunogenicity was completely preserved. Acid-environment-responsive modification, which releases a full repertoire of native allergen epitopes within a particular site, can be considered a smart drug delivery system, which is able to deliver a therapeutically-effective dose in a controlled manner, and minimizes adverse side effects.

The aim of this study was to investigate the survival of probiotics (Lactobacillus acidophilus NCFM, Lactobacillus rhamnosus HN001 and Bifidobacterium lactis HN019) in milk chocolate masses prepared at temperatures 35 degrees C and 40 degrees C. The influence of probiotics and preparation temperature on rheology, particle size distribution and sensory properties of the chocolates, was examined during 6 months of storage at 20 +/- 2 degrees C. An inoculation temperature of 40 degrees C significantly improves the rheological and sensory properties of probiotic chocolate, as well as leading to the survival of L. acidophilus NCFM and L. rhamnosus HN001 strains. After 6 months of storage, the survival of these strains was above 90%, with a viable cell count of about 8.1 log(CFU g(-1)). An inoculation temperature of 40 degrees C provides higher scores of overall sensory quality (4.52-4.68), higher quality category (excellent), lower maximal viscosity (for 1.2 Pa s) of chocolates, than a temperature of 35 degrees C. Compared to the chocolate without probiotics, those inoculated at 40 degrees C achieved less increase in volume weighted mean diameter distribution (average 0.8%) than chocolates inoculated at 35 degrees C. Based on the results reported in this paper, seeding of the probiotics in industrial conditions can be done in the mixing tank (at 40 degrees C) before the phase of chocolate shaping. Addition of probiotics at this stage facilitates the manufacturing process, improves the overall quality of chocolate and preserves the probiotics as a key component of this type of product.

Modified allergens are a safer and more efficient alternative to natural allergens for specific immunotherapy. As the modification of an allergen can diminish its immunogenicity due to the alteration of T-cell epitopes, in this paper we study the effects of a reversible chemical modification of Art v 1, the main allergen of mugwort pollen, on its allergenicity and immunogenicity. Modification of Art v 1 by cis-aconitylation into a polyanionic derivative (CAA) did not result in any significant structural alteration. However, IgE-binding epitopes on CAA were blocked, resulting in a reduced IgE-binding and basophil activation. Both proteins induced proliferation of CD3(+)CD4(+) T-cells in mugwort-allergic patients, but only unmodified allergens increased IL-4, IL-5 and IL-10 production. Rabbit and mouse anti-CAA antibodies exhibited cross-reactivity with native allergens and blocked human IgE-binding to Art v 1. Degradation of CAA by lysosomal fraction enzymes resulted in a similar set of peptides, harboring MHC class II-binding peptides, as unmodified proteins. Thus, cis-aconitylation modified Art v 1 had a significantly reduced allergenicity, whereas its immunogenicity was completely preserved. Acid-environment-responsive modification, which releases a full repertoire of native allergen epitopes within a particular site, can be considered a smart drug delivery system, which is able to deliver a therapeutically-effective dose in a controlled manner, and minimizes adverse side effects.

The electrochemical exfoliation of graphite to give one-atom-thick graphene with desirable properties is a green, cost-effective method for high-yield graphene production. This paper presents the results of electrochemical exfoliation of two different graphite precursors under an applied direct current voltage of +12 V. The used characterization techniques (elemental analysis, Fourier transform infrared spectroscopy, X-ray diffraction, X-photoelectron spectroscopy, Raman spectroscopy, field emission scanning electron microscopy and atomic force microscopy) showed that the exfoliated powder is highly functionalized with a low carbon/oxygen content that is similar to graphene oxide. The exfoliated graphene sheets dispersed in N,N-dimethylformamide were deposited on ano-discs by vacuum filtration and transferred to glass ceramic substrates. The thermal annealing of the as-deposited films at 600 degrees C for 30 minutes resulted in an increase in the carbon/oxygen ratio by more than 3 fold and a decrease in the sheet resistance by 25%. The lowest values for the sheet resistance of the annealed graphene thin films were in the range of 0.32 +/- 0.04 to 0.84 +/- 0.1 kohm sq(-1) depending on the graphite source that was used.

Modified allergens are a safer and more efficient alternative to natural allergens for specific immunotherapy. As the modification of an allergen can diminish its immunogenicity due to the alteration of T-cell epitopes, in this paper we study the effects of a reversible chemical modification of Art v 1, the main allergen of mugwort pollen, on its allergenicity and immunogenicity. Modification of Art v 1 by cis-aconitylation into a polyanionic derivative (CAA) did not result in any significant structural alteration. However, IgE-binding epitopes on CAA were blocked, resulting in a reduced IgE-binding and basophil activation. Both proteins induced proliferation of CD3(+)CD4(+) T-cells in mugwort-allergic patients, but only unmodified allergens increased IL-4, IL-5 and IL-10 production. Rabbit and mouse anti-CAA antibodies exhibited cross-reactivity with native allergens and blocked human IgE-binding to Art v 1. Degradation of CAA by lysosomal fraction enzymes resulted in a similar set of peptides, harboring MHC class II-binding peptides, as unmodified proteins. Thus, cis-aconitylation modified Art v 1 had a significantly reduced allergenicity, whereas its immunogenicity was completely preserved. Acid-environment-responsive modification, which releases a full repertoire of native allergen epitopes within a particular site, can be considered a smart drug delivery system, which is able to deliver a therapeutically-effective dose in a controlled manner, and minimizes adverse side effects.

The electrochemical exfoliation of graphite to give one-atom-thick graphene with desirable properties is a green, cost-effective method for high-yield graphene production. This paper presents the results of electrochemical exfoliation of two different graphite precursors under an applied direct current voltage of +12 V. The used characterization techniques (elemental analysis, Fourier transform infrared spectroscopy, X-ray diffraction, X-photoelectron spectroscopy, Raman spectroscopy, field emission scanning electron microscopy and atomic force microscopy) showed that the exfoliated powder is highly functionalized with a low carbon/oxygen content that is similar to graphene oxide. The exfoliated graphene sheets dispersed in N,N-dimethylformamide were deposited on ano-discs by vacuum filtration and transferred to glass ceramic substrates. The thermal annealing of the as-deposited films at 600 degrees C for 30 minutes resulted in an increase in the carbon/oxygen ratio by more than 3 fold and a decrease in the sheet resistance by 25%. The lowest values for the sheet resistance of the annealed graphene thin films were in the range of 0.32 +/- 0.04 to 0.84 +/- 0.1 kohm sq(-1) depending on the graphite source that was used.

The aim of this study was to investigate the survival of probiotics (Lactobacillus acidophilus NCFM, Lactobacillus rhamnosus HN001 and Bifidobacterium lactis HN019) in milk chocolate masses prepared at temperatures 35 degrees C and 40 degrees C. The influence of probiotics and preparation temperature on rheology, particle size distribution and sensory properties of the chocolates, was examined during 6 months of storage at 20 +/- 2 degrees C. An inoculation temperature of 40 degrees C significantly improves the rheological and sensory properties of probiotic chocolate, as well as leading to the survival of L. acidophilus NCFM and L. rhamnosus HN001 strains. After 6 months of storage, the survival of these strains was above 90%, with a viable cell count of about 8.1 log(CFU g(-1)). An inoculation temperature of 40 degrees C provides higher scores of overall sensory quality (4.52-4.68), higher quality category (excellent), lower maximal viscosity (for 1.2 Pa s) of chocolates, than a temperature of 35 degrees C. Compared to the chocolate without probiotics, those inoculated at 40 degrees C achieved less increase in volume weighted mean diameter distribution (average 0.8%) than chocolates inoculated at 35 degrees C. Based on the results reported in this paper, seeding of the probiotics in industrial conditions can be done in the mixing tank (at 40 degrees C) before the phase of chocolate shaping. Addition of probiotics at this stage facilitates the manufacturing process, improves the overall quality of chocolate and preserves the probiotics as a key component of this type of product.

Modified allergens are a safer and more efficient alternative to natural allergens for specific immunotherapy. As the modification of an allergen can diminish its immunogenicity due to the alteration of T-cell epitopes, in this paper we study the effects of a reversible chemical modification of Art v 1, the main allergen of mugwort pollen, on its allergenicity and immunogenicity. Modification of Art v 1 by cis-aconitylation into a polyanionic derivative (CAA) did not result in any significant structural alteration. However, IgE-binding epitopes on CAA were blocked, resulting in a reduced IgE-binding and basophil activation. Both proteins induced proliferation of CD3(+)CD4(+) T-cells in mugwort-allergic patients, but only unmodified allergens increased IL-4, IL-5 and IL-10 production. Rabbit and mouse anti-CAA antibodies exhibited cross-reactivity with native allergens and blocked human IgE-binding to Art v 1. Degradation of CAA by lysosomal fraction enzymes resulted in a similar set of peptides, harboring MHC class II-binding peptides, as unmodified proteins. Thus, cis-aconitylation modified Art v 1 had a significantly reduced allergenicity, whereas its immunogenicity was completely preserved. Acid-environment-responsive modification, which releases a full repertoire of native allergen epitopes within a particular site, can be considered a smart drug delivery system, which is able to deliver a therapeutically-effective dose in a controlled manner, and minimizes adverse side effects.

The aim of this study was to investigate the survival of probiotics (Lactobacillus acidophilus NCFM, Lactobacillus rhamnosus HN001 and Bifidobacterium lactis HN019) in milk chocolate masses prepared at temperatures 35 degrees C and 40 degrees C. The influence of probiotics and preparation temperature on rheology, particle size distribution and sensory properties of the chocolates, was examined during 6 months of storage at 20 +/- 2 degrees C. An inoculation temperature of 40 degrees C significantly improves the rheological and sensory properties of probiotic chocolate, as well as leading to the survival of L. acidophilus NCFM and L. rhamnosus HN001 strains. After 6 months of storage, the survival of these strains was above 90%, with a viable cell count of about 8.1 log(CFU g(-1)). An inoculation temperature of 40 degrees C provides higher scores of overall sensory quality (4.52-4.68), higher quality category (excellent), lower maximal viscosity (for 1.2 Pa s) of chocolates, than a temperature of 35 degrees C. Compared to the chocolate without probiotics, those inoculated at 40 degrees C achieved less increase in volume weighted mean diameter distribution (average 0.8%) than chocolates inoculated at 35 degrees C. Based on the results reported in this paper, seeding of the probiotics in industrial conditions can be done in the mixing tank (at 40 degrees C) before the phase of chocolate shaping. Addition of probiotics at this stage facilitates the manufacturing process, improves the overall quality of chocolate and preserves the probiotics as a key component of this type of product.

The electrochemical exfoliation of graphite to give one-atom-thick graphene with desirable properties is a green, cost-effective method for high-yield graphene production. This paper presents the results of electrochemical exfoliation of two different graphite precursors under an applied direct current voltage of +12 V. The used characterization techniques (elemental analysis, Fourier transform infrared spectroscopy, X-ray diffraction, X-photoelectron spectroscopy, Raman spectroscopy, field emission scanning electron microscopy and atomic force microscopy) showed that the exfoliated powder is highly functionalized with a low carbon/oxygen content that is similar to graphene oxide. The exfoliated graphene sheets dispersed in N,N'-dimethylformamide were deposited on ano-discs by vacuum filtration and transferred to glass ceramic substrates. The thermal annealing of the as-deposited films at 600 degrees C for 30 minutes resulted in an increase in the carbon/oxygen ratio by more than 3 fold and a decrease in the sheet resistance by 25%. The lowest values for the sheet resistance of the annealed graphene thin films were in the range of 0.32 +/- 0.04 to 0.84 +/- 0.1 kohm sq(-1) depending on the graphite source that was used.

Incorporation of suitable dopants in MgH2 is widely investigated as the way of improving hydrogen storage characteristics of this material. The catalytic role of transition metal dopants on hydrogen desorption from MgH2 is very promising, but further attention is required in order to optimize the experimental methods and design materials with desired properties. In this paper we investigate the role of Ti, Fe, and Mn on the transport properties of hydrogen in MgH2, which are marked as limiting factor in the effort to lower the hydrogen desorption temperature. Taking into account the lattice relaxation around the impurities, we consider a number of different diffusion paths in the pure and doped system. Using PAW DFT calculations in combination with the NEB method, we demonstrate that the diffusion of the most relevant positively charged hydrogen vacancy and negatively charged interstitial hydrogen atom is locally hindered by the presence of the impurity atoms.

Incorporation of suitable dopants in MgH2 is widely investigated as the way of improving hydrogen storage characteristics of this material. The catalytic role of transition metal dopants on hydrogen desorption from MgH2 is very promising, but further attention is required in order to optimize the experimental methods and design materials with desired properties. In this paper we investigate the role of Ti, Fe, and Mn on the transport properties of hydrogen in MgH2, which are marked as limiting factor in the effort to lower the hydrogen desorption temperature. Taking into account the lattice relaxation around the impurities, we consider a number of different diffusion paths in the pure and doped system. Using PAW DFT calculations in combination with the NEB method, we demonstrate that the diffusion of the most relevant positively charged hydrogen vacancy and negatively charged interstitial hydrogen atom is locally hindered by the presence of the impurity atoms.