The Role of TiO2 Doping on RuO2-Coated Electrodes for the Water Oxidation Reaction

Electrochemical water splitting into H2 and O2 presents a significant and challenging energy loss due to the high overpotential required at the anode. Today, in industrially relevant applications, dimensionally stable anodes (DSA) based on the electrocatalytic active RuO2 are conventionally utilized. To enhance the resistance against corrosion, incorporation of TiO2 in the RuO2-coated electrodes is widely employed. In the present work we have used scanning electrochemical microscopy (SECM) to demonstrate that TiO2-doped RuO2-coated electrodes, in addition to being more durable, also show an electrocatalytic activity that is, on average, 13% higher as compared to the pure RuO2-coated electrodes. We also demonstrate that cracks in the pure RuO2 coating are the most active zones, probably because Ti from the Ti support has diffused into the first applied layer of the RuO2 coating. To reveal the nature of this enhanced activity for water oxidation displayed on TiO2-doped RuO2 electrodes, we have employed X-ray photoelectron spectroscopy (XPS) for material characterization. The results show that the electrocatalytic activity enhancement displayed on the mixed (Ru1–x:Tix)O2 coating is promoted through a charge transfer from the RuO2 to the TiO2, which provides new and more reactive sites designated as activated RuO2δ+.This study has partly been carried out in the framework of the European Commission FP7 Initial Training Network “ELCAT”, Grant Agreement No. 214936-2. Portions of this research were performed at SPring-8 with the approval of Japan Synchrotron Radiation Research Institute as Nanotechnology Support Project of the Ministry of Education, Culture, Sports, Science and Technology (Proposal No. 2007A2005 and 2008A1671/BL-47XU)

Kanon eller inte kanon? : En enkätstudie bland samhällskunskapslärare i årskurs 7-9

The aim of the present study is to investigate whether social studies in compulsory school grades 7–9 can be perceived as having a clear canon regarding subject content, methods, used sources and examination methods. Previous research has suggested that social studies is unclear, vague and that it lacks a subject canon. The results of the present study points in both directions. On the one hand, the study shows that there is a clear core of content around which lower secondary social studies teaching revolves and a common foundation regarding how this content is mainly conveyed and examined. On the other hand, the study shows that there is also great variation between different teachers, variation that can be partly explained by the teachers' preferences. Different teachers seem to have different preferences when it comes to how they teach, what methods and sources they use and how sections are examined. For example, there are significant correlations between how teachers who use group-based methods also use group-based examinations. An important factor for the variation between teachers can be traced to gender. At group level, we see differences regarding male and female teachers based on subject matter, methods, sources and examination methods. In general, there is a common core for most social studies teachers, regardless of gender, but female teachers tend to cover a broader subject content, use a wider array of methods and sources and more varied forms of examination

Kanon eller inte kanon? : En enkätstudie bland samhällskunskapslärare i årskurs 7-9

The aim of the present study is to investigate whether social studies in compulsory school grades 7–9 can be perceived as having a clear canon regarding subject content, methods, used sources and examination methods. Previous research has suggested that social studies is unclear, vague and that it lacks a subject canon. The results of the present study points in both directions. On the one hand, the study shows that there is a clear core of content around which lower secondary social studies teaching revolves and a common foundation regarding how this content is mainly conveyed and examined. On the other hand, the study shows that there is also great variation between different teachers, variation that can be partly explained by the teachers' preferences. Different teachers seem to have different preferences when it comes to how they teach, what methods and sources they use and how sections are examined. For example, there are significant correlations between how teachers who use group-based methods also use group-based examinations. An important factor for the variation between teachers can be traced to gender. At group level, we see differences regarding male and female teachers based on subject matter, methods, sources and examination methods. In general, there is a common core for most social studies teachers, regardless of gender, but female teachers tend to cover a broader subject content, use a wider array of methods and sources and more varied forms of examination

Suggestions for revised working methods to ensure that maintenance measures detected during fault correction are implemented

Då entreprenörer utför felavhjälpningar och schemalagda underhåll i Vattenfall Eldistribution AB nät upptäcks regelbundet fel och brister. Dessa brister ska de enligt serviceavtal rapportera in och göra en beställning på arbete, ett åtgärdsförslag med hjälp aven applikation. Det sker regelbundet att dessa brister inte blir inrapporterade korrekt vilket leder till felaktigheter i budget, kvarvarande noteringar i SCADA-systemet som inte avslutas och att underhåll inte utförs. Detta är ett problem som har pågått under många år och som är svårt att få ordning på. Detta examensarbete är ett uppdrag från Vattenfall Eldistribution AB och behandlar processer för drift och underhållsåtgärder och har till syfte att analysera brister i de befintliga processerna och ger förslag på åtgärder. Analysen baseras på intervjuer med drift- och underhållspersonal.Det resultat som framkommit av utredningen, visar att det krävs både tid och budgetvanaför att skapa dessa beställningar genom applikationen, vilket gör inrapporteringen omständlig för många tekniker. Det blir informationsöverlämningar vilket är ineffektivt då beställningen inte utförs direkt och det kan leda till att viss information försvinner eller glöms av. Flera alternativ som dellösningar har tagits fram och kan kombineras och användas beroende på vilken inriktning Vattenfall Eldistribution AB vill ta. Alla alternativ som tagits fram kräver någon form av större systemförändrin

Suggestions for revised working methods to ensure that maintenance measures detected during fault correction are implemented

Då entreprenörer utför felavhjälpningar och schemalagda underhåll i Vattenfall Eldistribution AB nät upptäcks regelbundet fel och brister. Dessa brister ska de enligt serviceavtal rapportera in och göra en beställning på arbete, ett åtgärdsförslag med hjälp aven applikation. Det sker regelbundet att dessa brister inte blir inrapporterade korrekt vilket leder till felaktigheter i budget, kvarvarande noteringar i SCADA-systemet som inte avslutas och att underhåll inte utförs. Detta är ett problem som har pågått under många år och som är svårt att få ordning på. Detta examensarbete är ett uppdrag från Vattenfall Eldistribution AB och behandlar processer för drift och underhållsåtgärder och har till syfte att analysera brister i de befintliga processerna och ger förslag på åtgärder. Analysen baseras på intervjuer med drift- och underhållspersonal.Det resultat som framkommit av utredningen, visar att det krävs både tid och budgetvanaför att skapa dessa beställningar genom applikationen, vilket gör inrapporteringen omständlig för många tekniker. Det blir informationsöverlämningar vilket är ineffektivt då beställningen inte utförs direkt och det kan leda till att viss information försvinner eller glöms av. Flera alternativ som dellösningar har tagits fram och kan kombineras och användas beroende på vilken inriktning Vattenfall Eldistribution AB vill ta. Alla alternativ som tagits fram kräver någon form av större systemförändrin

Metal-free supercapacitor with aqueous electrolyte and low-cost carbon materials

Electric double-layer capacitors (EDLCs) or supercapacitors (SCs) are fast energy storage devices with high pulse efficiency and superior cyclability, which makes them useful in various applications including electronics, vehicles and grids. Aqueous SCs are considered to be more environmentally friendly than those based on organic electrolytes. Because of the corrosive nature of the aqueous environment, however, expensive electrochemically stable materials are needed for the current collectors and electrodes in aqueous SCs. This results in high costs for a given energy-storage capacity. To address this, we developed a novel low-cost aqueous SC using graphite foil as the current collector and a mix of graphene, nanographite, simple water-purification carbons and nanocellulose as electrodes. The electrodes were coated directly onto the graphite foil by using casting frames and the SCs were assembled in a pouch cell design. With this approach, we achieved a material cost reduction of greater than 90% while maintaining approximately one-half of the specific capacitance of a commercial unit, thus demonstrating that the proposed SC can be an environmentally friendly, low-cost alternative to conventional SCs.Published online:05 January 2017</p

Franck-Condon higher order lattice excitations in the LaFe(1-x)Cr(x)O3 (x=0, 0.1, 0.5, 0.9, 1.0) perovskites due to Fe-Cr charge transfer effects

First and higher order lattice excitiations in the B-site disordered perovskites LaFe(1-x)Cr(x)O3 (x = 0, 0.1, 0.5, 0.9, 1) and La(0.835)Sr(0.165)Fe(0.5)Cr(0.5)O(3-d) are investigated using temperature dependent and polarised inelastic light scattering [lambda = 515 nm (2.41 eV) and 676 nm (1.83 eV)] on oriented crystallites. A peak at approximately 2.4 eV in the imaginary part of the dielectric function of LaFe(0.5)Cr(0.5)O3 is assigned to a charge transfer from Fe 3+ (d5) to Cr 3+ (d3) ions and coupled the appearance of an intense Ag-like mode at approximately 700 cm-1 in the Raman data. This excitation is identified as a symmetric oxygen breathing mode activated by the Fe-Cr charge transfer through an orbital coupling mechanism. Higher order scattering (up to 7th order) of the intrinsic Raman active symmetric breathing mode is also explained by an orbital mediated, electron-phonon coupling, similar to the Franck-Condon effect observed in the Jahn-Teller active perovskite structured manganite LaMnO3. These results show that the Franck-Condon mechanism is a more common mechanism for resonant higher order scattering in solids than previously believed and propose the LaFe(1-x)Cr(x)O(3) system as a model system for electron-phonon coupling and higher order Raman scattering in solids

Physical and electrochemical properties of cobalt doped (ti,ru)O2 electrode coatings

The physical and electrochemical properties of ternary oxides Ti 0.7Ru0.3-xCoxO2 (x = 0.093 and x = 0) have been investigated and compared. Samples of three different thicknesses were prepared by spin-coating onto polished titanium to achieve uniform and well-defined coatings. The resulting electrodes were characterized with a variety of methods, including both physical and electrochemical methods. Doping with cobalt led to a larger number of micrometer-sized cracks in the coating, and coating grains half the size compared to the undoped samples (10 instead of 20 nm across). This is in agreement with a voltammetric charge twice as high, as estimated from cyclic voltammetry. There is no evidence of a Co 3O4 spinel phase, suggesting that the cobalt is mainly incorporated in the overall rutile structure of the (Ti,Ru)O2. The doped electrodes exhibited a higher activity for cathodic hydrogen evolution compared to the undoped electrodes, despite the fact that one third of the active ruthenium was substituted with cobalt. For anodic chlorine evolution, the activity was similar for both electrode types

Contacting paper-based supercapacitors to printed electronics on paper substrates

Hybrid printed electronics, in which printed structures and silicon-based components co-exist will likely be among the first commercial solutions. In this case the paper substrate acts much in the same way as circuit boards, containing conductive tracks and acting as a carrier for the electrical components. It is important to consider the contacting of the components to be able to produce low resistance electrical contacts to the conductive tracks. Supercapacitors are able to deliver a large amount of current in a short time and are a good option for short term energy storage and if the printed product is to be used only one, or a few times, it can be the only power source needed. When manufacturing printed electronics, the overall resistance of the printed tracks as well as the contact resistance of the mounted components will add up to the total resistance of the system. A high resistance will cause a voltage drop from the power source to the component. This will waste power that goes to Joule heating and also the voltage and current available to components may be too low to drive them. If the intention is to use a power supply such as batteries or solar cells this becomes a limitation. In this article have been tested several conductive adhesives used to contact paper based supercapacitors to ink jet printed silver tracks on paper. The best adhesive gives about 0.3 Ω per contact, a factor 17 better compared to the worst which gave 5 Ω. The peak power that is possible to take out from a printed system with a flexible battery and super capacitors is about 10 times higher than compared with the same system with only the battery

Supercapacitors with graphene coated paper electrodes

Paper based supercapacitors are prepared by stacking a paper between two graphene electrodes and soaking these in an aqueous electrolyte. We demonstrate that supercapacitors can easily be manufactured by using proven paper technologies. Several different electrode materials were compared and two types of contacting material, silver and graphite foil were tested. The influence of the paper used as separator was also investigated. The supercapacitors with a graphene-gold nanoparticle composite as electrodes showed a specific capacitance of up to 100 F/g and an energy density of 1.27 Wh/kg. The energy density can further be increased by using other electrolytes. The silver contacts showed a pseudo capacitance, which the graphite contacts did not. The papers tested had a minor effect on the capacitance, but they have an influence on the weight and the volume of the supercapacitor