Highly visible-light-active S,N-codoped anatase−rutile heterojunctions are reported for the first... more Highly visible-light-active S,N-codoped anatase−rutile heterojunctions are reported for the first time. The formation of heterojunctions at a relatively low temperature and visible-light activity are achieved through thiourea modification of the peroxo−titania complex. FT-IR spectroscopic studies indicated the formation of a Ti−thiourea complex upon reaction between peroxo−titania complex and thiourea. Decomposition of the Ti−thiourea complex and formation of visible-light-active S,N-codoped TiO2 heterojunctions are confirmed using X-ray diffraction, Raman spectroscopy, transmission electron microscopy, and UV/vis spectroscopic studies. Existence of sulfur as sulfate ions (S) and nitrogen as lattice (N−Ti−N) and interstitial (Ti−N−O) species in heterojunctions are identified using X-ray photoelectron spectroscopy (XPS) and FT-IR spectroscopic techniques. UV−vis and valence band XPS studies of these S,N-codoped heterojunctions proved the fact that the formation of isolated S 3p, N 2p...
Current Opinion in Green and Sustainable Chemistry
Abstract As antibiotic resistant bacteria and genes become more prevalent, novel methods to remov... more Abstract As antibiotic resistant bacteria and genes become more prevalent, novel methods to remove them from the environment need to be developed. Here we hope to give the case for the use of 2D nanomaterials that exhibit photocatalytic properties for their removal, what they can do and what the future could potentially hold for them. Why 2D materials should be used will be examined, what makes them useful and their effectiveness. The morphological effects of the crystals on photocatalytic activity will be discussed, looking at particle size effects and shape. Recent advances in the field will be highlighted, investigating novel developments in treatment and degradation. Finally, the challenges that 2D nanomaterials face for further development will be addressed, what issues they have and hurdles they need to overcome.
Anaerobic digestion (AD) has been recognised as an effective means of simultaneously producing en... more Anaerobic digestion (AD) has been recognised as an effective means of simultaneously producing energy while reducing greenhouse gas (GHG) emissions. Despite having a large agriculture sector, Ireland has experienced little uptake of the technology, ranking 20th within the EU-28. It is, therefore, necessary to understand the general opinions, willingness to adopt, and perceived obstacles of potential adopters of the technology. As likely primary users of this technology, a survey of Irish cattle farmers was conducted to assess the potential of on-farm AD for energy production in Ireland. The study seeks to understand farmers’ motivations, perceived barriers, and preferred business model. The study found that approximately 41% of the 91 respondents were interested in installing AD on their farming enterprise within the next five years. These Likely Adopters tended to have a higher level of education attainment, and together, currently hold 4379 cattle, potentially providing 37,122 t y...
Atomic and molecular level interactions in solutions dictate the structural and functional attrib... more Atomic and molecular level interactions in solutions dictate the structural and functional attributes of crystals. These features clearly dictate the properties of materials and their applicability in technologies. However, the microscopic phenomena of particle formation—nucleation and growth—in real systems are still not fully understood. Specifically, crystallisation occurring in closed systems are largely unproven. Combining coherent experimental data, we here demonstrate a fundamental nucleation-growth mechanism that occurs in a model zinc oxide system when particles are formed under continuous, rapid heating under closed reaction conditions. Defying all previous reports, we show that the nucleation commences only when the heating is terminated. A prenucleation clusters pathway is observed for nucleation, followed by crystallite assembly-growth. We show that the nucleation-growth processes result from temporal and dynamic activity of constituent ions and gaseous molecules in sol...
Abstract This work outlines a systematic and detailed study of the modification of anatase TiO2 w... more Abstract This work outlines a systematic and detailed study of the modification of anatase TiO2 with tungsten (W). The impact this coupling has on the temperature of the anatase to rutile phase transition and the photocatalytic degradation of 1,4-dioxane, a highly toxic compound that is increasingly present in water bodies is also studied. TiO2 composite photocatalysts with 2, 4, 8 and 16 mol. % W, respectively, were produced using a sol-gel process and then calcined between 500-1000 °C. The crystallinity and phase composition of pure and W - TiO2 photocatalysts were examined using X-ray Diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). All W-TiO2 composite photocatalysts demonstrated 100% anatase crystalline phase at calcination temperatures as high as 800 °C. Due to the retention of 26% anatase after calcination at 950 °C, 8 mol. % W was established as the optimum W loading for the development of high temperature stable anatase W-TiO2 composite photocatalysts. The % anatase content also significantly impacts the photocatalytic activity of the W - TiO2 composite photocatalysts. In the presence of solar light, 100% of 1,4-dioxane was successfully degraded by 2-W-TiO2, 4-W-TiO2 and 8-W-TiO2 composite photocatalysts, respectively, calcined at 800 °C. However, as the calcination temperature increases and the % anatase content decreases, only 70% of 1,4-dioxane was degraded when using 4-W-TiO2 and 8-W-TiO2 calcined at 900 °C. The highest % removal of 1,4-dioxane was also achieved using 8-W-TiO2 calcined at both 800 and 900 °C. 8-W-TiO2 is therefore considered the optimum sample for both photocatalysis and phase transition temperature.
The introduction of new energy levels in the forbidden band through the doping of metal ions is a... more The introduction of new energy levels in the forbidden band through the doping of metal ions is an effective strategy to improve the thermal stability of TiO2. In the present study, the impact of Ta doping on the anatase to rutile transition (ART), structural characteristics, anion and cation vacancy formation were investigated in detail using Density Functional Theory (DFT) and experimental characterisation including, X-ray diffraction (XRD), Raman, and X-ray photoelectron spectroscopy (XPS). The average crystallite size of TiO2 decreases with an increase in the Ta concentration. At high temperatures, more oxygen atoms entered the crystal lattice and occupy the vacancies, leading to lattice expansion. Importantly, we find that Ta doping preserved the anatase content of TiO2 up to annealing temperatures of 850 °C which allows anatase stability to be maintained at typical ceramic processing temperatures. The substitution of Ti4+ by the Ta5+ ions increased the electron concentration i...
Graphene oxide (GO) has broad potential in the biomedical sector. The oxygen-abundant nature of G... more Graphene oxide (GO) has broad potential in the biomedical sector. The oxygen-abundant nature of GO means the material is hydrophilic and readily dispersible in water. GO has also been known to improve cell proliferation, drug loading, and antimicrobial properties of composites. Electrospun composites likewise have great potential for biomedical applications because they are generally biocompatible and bioresorbable, possess low immune rejection risk, and can mimic the structure of the extracellular matrix. In the current review, GO-containing electrospun composites for tissue engineering applications are described in detail. In addition, electrospun GO-containing materials for their use in drug and gene delivery, wound healing, and biomaterials/medical devices have been examined. Good biocompatibility and anionic-exchange properties of GO make it an ideal candidate for drug and gene delivery systems. Drug/gene delivery applications for electrospun GO composites are described with a number of examples. Various systems using electrospun GO-containing therapeutics have been compared for their potential uses in cancer therapy. Micro- to nanosized electrospun fibers for wound healing applications and antimicrobial applications are explained in detail. Applications of various GO-containing electrospun composite materials for medical device applications are listed. It is concluded that the electrospun GO materials will find a broad range of biomedical applications such as cardiac patches, medical device coatings, sensors, and triboelectric nanogenerators for motion sensing and biosensing.
The outbreak of COVID-19 has spread rapidly across the globe, greatly affecting how humans as a w... more The outbreak of COVID-19 has spread rapidly across the globe, greatly affecting how humans as a whole interact, work and go about their daily life. One of the key pieces of personal protective equipment (PPE) that is being utilised to return to the norm is the face mask or respirator. In this review we aim to examine face masks and respirators, looking at the current materials in use and possible future innovations that will enhance their protection against SARS-CoV-2. Previous studies concluded that cotton, natural silk and chiffon could provide above 50% efficiency. In addition, it was found that cotton quilt with a highly tangled fibrous nature provides efficient filtration in the small particle size range. Novel designs by employing various filter materials such as nanofibres, silver nanoparticles, and nano-webs on the filter surfaces to induce antimicrobial properties are also discussed in detail. Modification of N95/N99 masks to provide additional filtration of air and to deac...
European Union’s INTERREG VA Programme and Department of Jobs, Enterprise and Innovation, Ireland... more European Union’s INTERREG VA Programme and Department of Jobs, Enterprise and Innovation, Ireland (Renewable Engine (RE) project funded by European Union’s INTERREG VA Programme, managed by the Special EU Programmes Body (SEUPB), with match funding provided by the Department of Economy, Department of Jobs, Enterprise and Innovation in Ireland); Science Foundation Ireland ((SFI through the ERA.Net for Materials Research and Innovation (M-ERA.Net 2), SFI Grant Number SFI/16/M-ERA/3418 (RATOCAT)); SFI funded computing resources at Tyndall Institute and the SFI/HEA funded Irish Centre for High End Computing)); European Cooperation in Science and Technology (COST Action CM1104 “Reducible Metal Oxides, Structure and Function”); Universidad de Valladolid and Banco Santander (“Movilidad UVa-BANCO SANTANDER 2019”); Universidad de Valladolid (Research initiative “Catedra de Conocimiento e Innovacion” from “Caja Rural de Soria”)
The advanced electrochemical properties, such as high energy density, fast charge–discharge rates... more The advanced electrochemical properties, such as high energy density, fast charge–discharge rates, excellent cyclic stability, and specific capacitance, make supercapacitor a fascinating electronic device. During recent decades, a significant amount of research has been dedicated to enhancing the electrochemical performance of the supercapacitors through the development of novel electrode materials. In addition to highlighting the charge storage mechanism of the three main categories of supercapacitors, including the electric double-layer capacitors (EDLCs), pseudocapacitors, and the hybrid supercapacitors, this review describes the insights of the recent electrode materials (including, carbon-based materials, metal oxide/hydroxide-based materials, and conducting polymer-based materials, 2D materials). The nanocomposites offer larger SSA, shorter ion/electron diffusion paths, thus improving the specific capacitance of supercapacitors (SCs). Besides, the incorporation of the redox-ac...
Highly visible-light-active S,N-codoped anatase−rutile heterojunctions are reported for the first... more Highly visible-light-active S,N-codoped anatase−rutile heterojunctions are reported for the first time. The formation of heterojunctions at a relatively low temperature and visible-light activity are achieved through thiourea modification of the peroxo−titania complex. FT-IR spectroscopic studies indicated the formation of a Ti−thiourea complex upon reaction between peroxo−titania complex and thiourea. Decomposition of the Ti−thiourea complex and formation of visible-light-active S,N-codoped TiO2 heterojunctions are confirmed using X-ray diffraction, Raman spectroscopy, transmission electron microscopy, and UV/vis spectroscopic studies. Existence of sulfur as sulfate ions (S) and nitrogen as lattice (N−Ti−N) and interstitial (Ti−N−O) species in heterojunctions are identified using X-ray photoelectron spectroscopy (XPS) and FT-IR spectroscopic techniques. UV−vis and valence band XPS studies of these S,N-codoped heterojunctions proved the fact that the formation of isolated S 3p, N 2p...
Current Opinion in Green and Sustainable Chemistry
Abstract As antibiotic resistant bacteria and genes become more prevalent, novel methods to remov... more Abstract As antibiotic resistant bacteria and genes become more prevalent, novel methods to remove them from the environment need to be developed. Here we hope to give the case for the use of 2D nanomaterials that exhibit photocatalytic properties for their removal, what they can do and what the future could potentially hold for them. Why 2D materials should be used will be examined, what makes them useful and their effectiveness. The morphological effects of the crystals on photocatalytic activity will be discussed, looking at particle size effects and shape. Recent advances in the field will be highlighted, investigating novel developments in treatment and degradation. Finally, the challenges that 2D nanomaterials face for further development will be addressed, what issues they have and hurdles they need to overcome.
Anaerobic digestion (AD) has been recognised as an effective means of simultaneously producing en... more Anaerobic digestion (AD) has been recognised as an effective means of simultaneously producing energy while reducing greenhouse gas (GHG) emissions. Despite having a large agriculture sector, Ireland has experienced little uptake of the technology, ranking 20th within the EU-28. It is, therefore, necessary to understand the general opinions, willingness to adopt, and perceived obstacles of potential adopters of the technology. As likely primary users of this technology, a survey of Irish cattle farmers was conducted to assess the potential of on-farm AD for energy production in Ireland. The study seeks to understand farmers’ motivations, perceived barriers, and preferred business model. The study found that approximately 41% of the 91 respondents were interested in installing AD on their farming enterprise within the next five years. These Likely Adopters tended to have a higher level of education attainment, and together, currently hold 4379 cattle, potentially providing 37,122 t y...
Atomic and molecular level interactions in solutions dictate the structural and functional attrib... more Atomic and molecular level interactions in solutions dictate the structural and functional attributes of crystals. These features clearly dictate the properties of materials and their applicability in technologies. However, the microscopic phenomena of particle formation—nucleation and growth—in real systems are still not fully understood. Specifically, crystallisation occurring in closed systems are largely unproven. Combining coherent experimental data, we here demonstrate a fundamental nucleation-growth mechanism that occurs in a model zinc oxide system when particles are formed under continuous, rapid heating under closed reaction conditions. Defying all previous reports, we show that the nucleation commences only when the heating is terminated. A prenucleation clusters pathway is observed for nucleation, followed by crystallite assembly-growth. We show that the nucleation-growth processes result from temporal and dynamic activity of constituent ions and gaseous molecules in sol...
Abstract This work outlines a systematic and detailed study of the modification of anatase TiO2 w... more Abstract This work outlines a systematic and detailed study of the modification of anatase TiO2 with tungsten (W). The impact this coupling has on the temperature of the anatase to rutile phase transition and the photocatalytic degradation of 1,4-dioxane, a highly toxic compound that is increasingly present in water bodies is also studied. TiO2 composite photocatalysts with 2, 4, 8 and 16 mol. % W, respectively, were produced using a sol-gel process and then calcined between 500-1000 °C. The crystallinity and phase composition of pure and W - TiO2 photocatalysts were examined using X-ray Diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). All W-TiO2 composite photocatalysts demonstrated 100% anatase crystalline phase at calcination temperatures as high as 800 °C. Due to the retention of 26% anatase after calcination at 950 °C, 8 mol. % W was established as the optimum W loading for the development of high temperature stable anatase W-TiO2 composite photocatalysts. The % anatase content also significantly impacts the photocatalytic activity of the W - TiO2 composite photocatalysts. In the presence of solar light, 100% of 1,4-dioxane was successfully degraded by 2-W-TiO2, 4-W-TiO2 and 8-W-TiO2 composite photocatalysts, respectively, calcined at 800 °C. However, as the calcination temperature increases and the % anatase content decreases, only 70% of 1,4-dioxane was degraded when using 4-W-TiO2 and 8-W-TiO2 calcined at 900 °C. The highest % removal of 1,4-dioxane was also achieved using 8-W-TiO2 calcined at both 800 and 900 °C. 8-W-TiO2 is therefore considered the optimum sample for both photocatalysis and phase transition temperature.
The introduction of new energy levels in the forbidden band through the doping of metal ions is a... more The introduction of new energy levels in the forbidden band through the doping of metal ions is an effective strategy to improve the thermal stability of TiO2. In the present study, the impact of Ta doping on the anatase to rutile transition (ART), structural characteristics, anion and cation vacancy formation were investigated in detail using Density Functional Theory (DFT) and experimental characterisation including, X-ray diffraction (XRD), Raman, and X-ray photoelectron spectroscopy (XPS). The average crystallite size of TiO2 decreases with an increase in the Ta concentration. At high temperatures, more oxygen atoms entered the crystal lattice and occupy the vacancies, leading to lattice expansion. Importantly, we find that Ta doping preserved the anatase content of TiO2 up to annealing temperatures of 850 °C which allows anatase stability to be maintained at typical ceramic processing temperatures. The substitution of Ti4+ by the Ta5+ ions increased the electron concentration i...
Graphene oxide (GO) has broad potential in the biomedical sector. The oxygen-abundant nature of G... more Graphene oxide (GO) has broad potential in the biomedical sector. The oxygen-abundant nature of GO means the material is hydrophilic and readily dispersible in water. GO has also been known to improve cell proliferation, drug loading, and antimicrobial properties of composites. Electrospun composites likewise have great potential for biomedical applications because they are generally biocompatible and bioresorbable, possess low immune rejection risk, and can mimic the structure of the extracellular matrix. In the current review, GO-containing electrospun composites for tissue engineering applications are described in detail. In addition, electrospun GO-containing materials for their use in drug and gene delivery, wound healing, and biomaterials/medical devices have been examined. Good biocompatibility and anionic-exchange properties of GO make it an ideal candidate for drug and gene delivery systems. Drug/gene delivery applications for electrospun GO composites are described with a number of examples. Various systems using electrospun GO-containing therapeutics have been compared for their potential uses in cancer therapy. Micro- to nanosized electrospun fibers for wound healing applications and antimicrobial applications are explained in detail. Applications of various GO-containing electrospun composite materials for medical device applications are listed. It is concluded that the electrospun GO materials will find a broad range of biomedical applications such as cardiac patches, medical device coatings, sensors, and triboelectric nanogenerators for motion sensing and biosensing.
The outbreak of COVID-19 has spread rapidly across the globe, greatly affecting how humans as a w... more The outbreak of COVID-19 has spread rapidly across the globe, greatly affecting how humans as a whole interact, work and go about their daily life. One of the key pieces of personal protective equipment (PPE) that is being utilised to return to the norm is the face mask or respirator. In this review we aim to examine face masks and respirators, looking at the current materials in use and possible future innovations that will enhance their protection against SARS-CoV-2. Previous studies concluded that cotton, natural silk and chiffon could provide above 50% efficiency. In addition, it was found that cotton quilt with a highly tangled fibrous nature provides efficient filtration in the small particle size range. Novel designs by employing various filter materials such as nanofibres, silver nanoparticles, and nano-webs on the filter surfaces to induce antimicrobial properties are also discussed in detail. Modification of N95/N99 masks to provide additional filtration of air and to deac...
European Union’s INTERREG VA Programme and Department of Jobs, Enterprise and Innovation, Ireland... more European Union’s INTERREG VA Programme and Department of Jobs, Enterprise and Innovation, Ireland (Renewable Engine (RE) project funded by European Union’s INTERREG VA Programme, managed by the Special EU Programmes Body (SEUPB), with match funding provided by the Department of Economy, Department of Jobs, Enterprise and Innovation in Ireland); Science Foundation Ireland ((SFI through the ERA.Net for Materials Research and Innovation (M-ERA.Net 2), SFI Grant Number SFI/16/M-ERA/3418 (RATOCAT)); SFI funded computing resources at Tyndall Institute and the SFI/HEA funded Irish Centre for High End Computing)); European Cooperation in Science and Technology (COST Action CM1104 “Reducible Metal Oxides, Structure and Function”); Universidad de Valladolid and Banco Santander (“Movilidad UVa-BANCO SANTANDER 2019”); Universidad de Valladolid (Research initiative “Catedra de Conocimiento e Innovacion” from “Caja Rural de Soria”)
The advanced electrochemical properties, such as high energy density, fast charge–discharge rates... more The advanced electrochemical properties, such as high energy density, fast charge–discharge rates, excellent cyclic stability, and specific capacitance, make supercapacitor a fascinating electronic device. During recent decades, a significant amount of research has been dedicated to enhancing the electrochemical performance of the supercapacitors through the development of novel electrode materials. In addition to highlighting the charge storage mechanism of the three main categories of supercapacitors, including the electric double-layer capacitors (EDLCs), pseudocapacitors, and the hybrid supercapacitors, this review describes the insights of the recent electrode materials (including, carbon-based materials, metal oxide/hydroxide-based materials, and conducting polymer-based materials, 2D materials). The nanocomposites offer larger SSA, shorter ion/electron diffusion paths, thus improving the specific capacitance of supercapacitors (SCs). Besides, the incorporation of the redox-ac...
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