<p>Materials prepared on the nanoscale often exhibit many different properties compared to the same materials in their bulk-state. Interest in nanostructured materials has increased because of these properties in fields such as microelectronics, catalysis, optics and sensors. This increased interest in nanostructured materials calls for new and more precise fabrication techniques.</p><p>This thesis describes how to use the porous anodic aluminium oxide as a template for the fabrication of a variety of nanostructured materials. Palladium and copper nanoparticles were deposited along the pore walls in anodic aluminum oxide using electroless deposition and atomic layer deposition. In both cases, it was possible to control the size of the nanoparticles by carefully monitoring the deposition parameters. The thesis also describes how Prussian blue nanoparticles and nanotubes can be fabricated using the anodic aluminium oxide as a template. The deposition of Prussian blue was performed by a sequential wet-chemical method. By using atomic layer deposition, it was also possible to deposit thin films of amorphous Nb2O5 on the pore walls. When the template was removed by etching, freestanding nanotubes were obtained. The anodic aluminium oxide membrane was also used as a mask for high energy (MeV) ion irradiation of an underlying substrate. The tracks produced were etched away with hydrogen fluoride. In this way, it was possible to transfer the highly ordered porous pattern from the mask onto other oxides such as SiO2 and TiO2.</p><p>All fabricated structures were characterized using a variety of analysis techniques: scanning electron microscopy for evaluating sample morphology; transmission electron microscopy for better resolved investigations of the morphology; X-ray diffraction to assess crystallinity; energy dispersive spectroscopy and X-ray fluorescence spectroscopy to determine the elemental composition and identify possible contaminants.</p><p>The general aim of the work described in this thesis has been to create a set of tools for use in the fabrication of a variety of nanostructured materials, whose dimensions composition can be tailored by selecting appropriate fabrication methods and parameters.</p>

<p>In the history of Chemistry, materials chemists have developed their ideas mainly by doing experiments in laboratories. The underlying motivation for this laboratory work has generally been pure curiosity or the ambition to find a solution to a specific problem. Minor changes in the composition or structure of a material can cause major changes in its properties. The development of powerful computers has now opened up the possibility to calculate properties of new materials using quantum mechanical methods.</p><p>The Chemistry of different boron-related materials has been evaluated in this thesis by Density Functional Theory (DFT). Cubic boron nitride (c-BN) is a most interesting material for the microelectronics and tool industry. During thin film deposition of c-BN, several problems arise which most often result in unwanted BN isomorphs. Chemical processes at the (110) and (111) surface of c-BN have been investigated in order to shed light upon some of these complex processes. Typically adsorption energies and surface reconstruction were found to differ significantly between the two surfaces. </p><p>Other materials investigated are layered transition-metal diborides (MeB₂). Incorporation of transition-metal atoms into elemental boron in its most fundamental structure, ά-boron, has also been investigated. The calculations on MeB₂ focused on the stability of the planar compared to the puckered structure of MeB₂. Stability was investigated by calculating Density of States (DOS) and bond populations. Deviations in the cell parameters from their ideal values were also considered. </p><p>A separate project concerned reactivity of the TiB₂(001) surface. Molecular and dissociated adsorption energies and adsorption geometries were calculated for H₂, H₂O and O₂. It was concluded that the titanium surface was more reactive than the boron surface and that the adsorption energies were comparable to or stronger than other well known surface-active compounds like TiO₂.</p>

Fosfaters reaktioner i energiomvandlingsprocesser är kritisk för den generella processen som helhet, för askrelaterade problem, emissioner liksom för en effektiv och hållbar användning av askan. Denna avhandling är en sammanställning och diskussion med utgångspunkt i åtta artiklar som behandlar strukturella och termodynamiska studier på faser i CaO-K2O-P2O5-systemet, vilka är av relevans inom förbränning av biomassa. Målsättningen med denna avhandling var: i) att sammanställa och granska tillgängliga strukturella och termodynamiska data i CaO-K2O-P2O5-systemet samt att identifiera avsaknad av data, ii) att fylla i dessa luckor med grundläggande termodynamiska, strukturella och fasstabilitets studier samt iii) att visa på användning samt fördelarna med dessa nya data vid praktisk tillämpning. En initial litteraturundersökning i CaO-K2O-P2O5-systemet visade att det saknades både strukturella och termodynamiska data. När det gällde tillgängliga termodynamiska data var situationen särskilt otillfredsställande. Det fanns endast data för några kalcium– och kaliumfosfater med varierande tillförlitlighet. Situationen beträffande pulverröntgen för fasidentifiering var bättre, fast fördunklad av det faktum att strukturellt liknande fasövergångar ofta förekommer i det undersökta systemet. Däremot fattades det tillfredställande enkristallstrukturdata för ternära faser i det undersökta systemet. Enkristallröntgendiffraktion användes för att bestämma strukturerna för CaK2P2O7, CaKP3O9, Ca10K(PO4)7 och CaKPO4. Faserna CaK2P2O7 and CaKPO4 tillsammans med Ca3(PO4)2, KPO3 och K4P2O7 studerades med pulverröntgendiffraktion och termiska analysmetoder för att klargöra fasmodifikationer och övergångstemperaturer. Gibbs bildningsenergi bestämdes för Ca(PO3)2, Ca2P2O7, Ca3(PO4)2, Ca10K(PO4)7, CaK2P2O7, CaKPO4 och CaK4(PO4)2 med ems-metodik och yttriastabiliserad zirkonia som fast elektrolyt och Ni/Ni3P som hjälpsystem. Både de strukturella och termodynamiska data användes sedan vid analyser i ett förbrännningexperiment av olika sädesslag. Framtagna data användes både vid identifiering och även vid kvantifiering av bildade faser i biomassaresterna. / The behaviour of phosphates in thermochemical biomass conversion processes are critical for the general process chemistry, for ash related problems, for emissions as well as for an efficient, sustainable and beneficial use of the ash residues. This thesis is a summary and a discussion of eight papers dealing with structural and thermodynamical studies of phases in the CaO-K2O-P2O5 system, with relevance for biomass combustion. The objectives were: i) to compile and review the available structural and thermodynamical data of phases in the CaO-K2O-P2O5 system as well as to identify existing gaps in the field of these data, ii) to fill in as many as possible of the gaps by fundamental thermodynamic, structural and phase stability studies and iii) to demonstrate the uses and the benefits of the new data in practical applications. An initial review of the CaO-K2O-P2O5 system showed that both structural information and thermodynamic data were lacking. The situation regarding the available thermodynamic data was especially unsatisfactory, data could only be found for some few calcium phosphates and a few potassium phosphates with varying reliability. Concerning powder X-ray diffraction patterns for phase identification the situation was better, though obscured by the fact that structurally close related phase transitions often occur in the studied system. However, adequate single crystal structural data of ternary phases in the system was completely missing. Crystal structures of CaK2P2O7, CaKP3O9, Ca10K(PO4)7 and CaKPO4 were determined by single-crystal X-ray diffraction. The phases CaK2P2O7 and CaKPO4 were together with Ca3(PO4)2, KPO3 and K4P2O7, investigated by powder X-ray diffraction and thermal analysis to elucidate phase modifications and transitions temperatures. Gibbs standard energy of formation was determined for Ca(PO3)2, Ca2P2O7, Ca3(PO4)2, Ca10K(PO4)7, CaK2P2O7, CaKPO4 and CaK4(PO4)2 by solid state emf measurements with yttria stabilised zirconia as solid electrolyte and Ni/Ni3P as auxiliary solid couple. Both the structural and thermodynamical data were subsequently utilised in analysis of a combustion experiment of cereal grains. The data were also used to both identify and quantify the phases formed in biomass combustion residues.

Materials prepared on the nanoscale often exhibit many different properties compared to the same materials in their bulk-state. Interest in nanostructured materials has increased because of these properties in fields such as microelectronics, catalysis, optics and sensors. This increased interest in nanostructured materials calls for new and more precise fabrication techniques. This thesis describes how to use the porous anodic aluminium oxide as a template for the fabrication of a variety of nanostructured materials. Palladium and copper nanoparticles were deposited along the pore walls in anodic aluminum oxide using electroless deposition and atomic layer deposition. In both cases, it was possible to control the size of the nanoparticles by carefully monitoring the deposition parameters. The thesis also describes how Prussian blue nanoparticles and nanotubes can be fabricated using the anodic aluminium oxide as a template. The deposition of Prussian blue was performed by a sequential wet-chemical method. By using atomic layer deposition, it was also possible to deposit thin films of amorphous Nb2O5 on the pore walls. When the template was removed by etching, freestanding nanotubes were obtained. The anodic aluminium oxide membrane was also used as a mask for high energy (MeV) ion irradiation of an underlying substrate. The tracks produced were etched away with hydrogen fluoride. In this way, it was possible to transfer the highly ordered porous pattern from the mask onto other oxides such as SiO2 and TiO2. All fabricated structures were characterized using a variety of analysis techniques: scanning electron microscopy for evaluating sample morphology; transmission electron microscopy for better resolved investigations of the morphology; X-ray diffraction to assess crystallinity; energy dispersive spectroscopy and X-ray fluorescence spectroscopy to determine the elemental composition and identify possible contaminants. The general aim of the work described in this thesis has been to create a set of tools for use in the fabrication of a variety of nanostructured materials, whose dimensions composition can be tailored by selecting appropriate fabrication methods and parameters.

In the history of Chemistry, materials chemists have developed their ideas mainly by doing experiments in laboratories. The underlying motivation for this laboratory work has generally been pure curiosity or the ambition to find a solution to a specific problem. Minor changes in the composition or structure of a material can cause major changes in its properties. The development of powerful computers has now opened up the possibility to calculate properties of new materials using quantum mechanical methods. The Chemistry of different boron-related materials has been evaluated in this thesis by Density Functional Theory (DFT). Cubic boron nitride (c-BN) is a most interesting material for the microelectronics and tool industry. During thin film deposition of c-BN, several problems arise which most often result in unwanted BN isomorphs. Chemical processes at the (110) and (111) surface of c-BN have been investigated in order to shed light upon some of these complex processes. Typically adsorption energies and surface reconstruction were found to differ significantly between the two surfaces. Other materials investigated are layered transition-metal diborides (MeB2). Incorporation of transition-metal atoms into elemental boron in its most fundamental structure, ά-boron, has also been investigated. The calculations on MeB2 focused on the stability of the planar compared to the puckered structure of MeB2. Stability was investigated by calculating Density of States (DOS) and bond populations. Deviations in the cell parameters from their ideal values were also considered. A separate project concerned reactivity of the TiB2(001) surface. Molecular and dissociated adsorption energies and adsorption geometries were calculated for H2, H2O and O2. It was concluded that the titanium surface was more reactive than the boron surface and that the adsorption energies were comparable to or stronger than other well known surface-active compounds like TiO2.

Biomimetic chemistry is directed towards the simulation of enzymatic reactivity with synthetic analogues. In this thesis a quantum chemical method has been employed to study the mechanism of highly reactive iron-oxo complexes involved in oxygenation and chlorination of organic substrates. The aim of this research is to gain greater understanding for the reactivity paradigm of the iron-oxo group. One reaction deals with the conversion of cyclohexane into adipic acid, a key chemical in industrial chemistry, catalyzed by an iron(II)-porphyrin complex in the presence of dioxygen. This process constitutes a ’green’ alternative to conventional adipic acid production, and is thus of great interest to synthetic chemistry. Another reaction investigated herein regards the selective chlorination observed for a new group of non-heme iron enzymes. With help of theoretical modeling it was possible to propose a mechanism that explains the observed selectivity. It is furthermore demonstrated how a biomimetic iron complex simulates the enzymatic reactivity by a different mechanism. Other topics covered in this thesis regard the structure-reactivity relationship of a binuclear iron complex and the intradiol C-C bond cleavage of catechol catalyzed by an iron(III) complex. / At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 1: Submitted. Paper 2: Accepted. Paper 3: Submitted.

Most electrical, magnetic or optical devices are today based on several, usually extremely thin layers of different materials.  In this thesis chemical synthesis processes have been developed for growth of less stable and metastable layers, and even multilayers, of nickel containing compounds. A chemical vapor deposition (CVD) method for deposition of metastable Ni3N has been developed.  The deposition process employs ammonia as nitrogen precursor. An atomic layer deposition (ALD) process for deposition of both polycrystalline and epitaxial NiO and using low oxygen activity, has also been developed. Both deposition processes utilizes bis(2,2,6,6-tetramethyl-3,5-heptanedionato)nickel(II) (Ni(thd)2) as the metal precursor. The Ni3N deposition proceeds via surface reactions. The growth rate is very sensitive to the partial pressure of ammonia, why adsorbed –NHx species are believed to be of importance for the film growth. Similar reactions can be expected between the metal precursor and H2O. For ALD of NiO a large excess of water was needed For the multilayered structures of Ni3N/NiO, growth processes, working at low activities of oxygen and hydrogen, are needed to avoid oxidation or reduction of the underlying layer. Chemical vapor growth methods such as CVD and ALD are often suffering from using high activities of hydrogen or oxygen to deposit metals and oxides. An alternative deposition pathway for metal deposition, without any hydrogen in the vapor, has been demonstrated. The metal has been formed by decomposition of the metastable nitride Ni3N in a post-annealing process.  Ni3N decomposes via different mechanisms, depending on environment in the annealing process. The different mechanisms result in different degrees of ordering in the resulting Ni films. From the knowledge gained about the chemical growth of NiO and Ni3N as well as the decomposition of Ni3N, well-defined multilayer structures have been produced in different combinations of NiO, Ni3N and Ni.

There are today clear indications that the Li-ion battery of the type currently used worldwide in mobile-phones and lap-tops is also destined to soon become the battery of choice in more energy-demanding concepts such as electric and electric hybrid vehicles (EVs and EHVs). Since the currently used cathode materials (typically of the Li(Ni,Co)O2-type) are too expensive in large-scale applications, these new batteries will have to exploit some much cheaper transition-metal. Ideally, this should be the very cheapest - iron(Fe) - in combination with a graphite(C)-based anode. In this context, the obvious Fe-based active cathode of choice appears to be LiFePO4. A second and in some ways even more attractive material - Li2FeSiO4 - has emerged during the course of this work. An effort has here been made to understand the Li extraction/insertion mechanism on electrochemical cycling of Li2FeSiO4. A fascinating picture has emerged (following a complex combination of Mössbauer, X-ray diffraction and electrochemical studies) in which the material is seen to cycle between Li2FeSiO4 and LiFeSiO4, but with the structure of the original Li2FeSiO4 transforming from a metastable short-range ordered solid-solution into a more stable long-range ordered structure during the first cycle. Density Functional Theory calculations on Li2FeSiO4 and the delithiated on LiFeSiO4 structure provide an interesting insight into the experimental result. Photoelectron spectroscopy was used to study the surface chemistry of both carbon-treated LiFePO4 and Li2FeSiO4 after electrochemical cycling. The surface-layer on both materials was concluded to be very thin and with incomplete coverage, giving the promise of good long-term cycling. LiFePO4 and Li2FeSiO4 should both be seen as highly promising candidates as positive-electrode materials for large-scale Li-ion battery applications.

ZnO nanoparticles in the size range 2.5–7 nm have been synthesised by a wet chemical method where ZnO particles were grown in basic zinc acetate solution. The optical band gap increases when the size of the particles decreases. An empirical relation between the optical band gap given from absorption measurements, and particle size given from XRD measurements has been developed and compared to other similar relations found in the literature.    Time resolved UV-Vis spectroscopy has been used to follow the growth of particles in situ in solution. The data show that the growth mechanism not can be described by a simple Oswald ripening approach and nor by an exclusive agglomeration of smaller clusters into larger particles. The growth mechanism is more likely a combination of the proposed reaction themes. The data also reveal that particle formation do not demand a heating step for formation of the commonly assumed initial cluster Zn4O(CH3COO)6.    Steady state fluorescence has been studied as a function of particle size during growth in solution. These measurements confirm what is found in the literature in that the visible fluorescence is shifted to longer wavelengths and loses in intensity as the particles grow. Some picosecond spectroscopy has also been done where the UV fluorescence has been investigated. From these measurements it is apparent that the lifetime of the fluorescence increases with particle size.     The phonon spectrum of ZnO has been studied with Raman spectroscopy for a number of different particle sizes. From these measurements it is clear that there is a strong quenching of the phonons due to confinement for the small particles, and the only clearly observed vibration is one at 436 cm-1 which intensity strongly increases with particle size.

Due to the increasing usage of Sn in different electronics, such as solders and in touchscreens, together with Boliden Rönnskärs increased intake of electronic waste as a secondaryraw material, a Zn-containing product called Zn-clinker has increasing amounts of Sn. TheZn-clinker is shipped to Boliden Zn-smelter in Odda, where the Zn-clinker is mixed in withcalcine (roasted concentrate) and leached in several steps. Since Zn-clinker is a product froma halogen removal in a clinker-furnace, the feed material (Mixed Oxide), for this furnace, wasalso investigated since there are plans to replace clinkering with soda-washing in the future.Most of the Sn ends up in the leaching residue which then is deposited in the mountaincaverns close by the Boliden Odda smelter. Boliden is studying the possibility to recoverPb/Ag and Sn content from the leaching residue and create a valuable by-product. Bystudying how the leaching of Sn behaves, together with a characterization of the materials, thefollowing question should be answered: “During which sulphuric acid leaching conditions, ofZn-clinker and Mixed Oxide, is the leaching of Sn minimized?” The leaching results for Zn-clinker showed that 8-10% Sn will leach out, despite changingtemperature, redox potential, time and pH. A characterization of the material with SEM-EDSand XRD-analysis was also conducted to see if Sn could be identified in any phases in thematerials. The studies provided enough evidence that Zn2SnO4 could be concluded to be themain phase in the leaching residue for Zn-clinker, a form that would not leach underconditions presented in this project. However, 8-10% of the Sn will come together with Feand when Fe leach out, so does Sn. The leaching results for Mixed Oxide pointed towards that different phases from them foundin Zn-clinker was present. Sn losses varied between 10-20% but raised to 47% whentemperature was changed to 80 °C during leaching. The SEM-EDS analysis showed that theidentified Sn-phases contained more Sn than in Zn-clinker and together with the leachingresults, a conclusion that Sn would mainly be found as SnO2 or SnO in the Mixed Oxide, butthere is still uncertainty about the distributions of these forms. Unfortunately half of the As leached out during the soda-washing for Mixed Oxide, creating aleachate with Cl, F and As that need to be taken care of. This could be challenging andpresenting a costly side-project for the route different from the Zn-clinker route used today.Another observation was that PbCO3 formed during the soda-washing, a phase that willconsume more sulphuric acid during leaching.