Gallery

Here you can find pictures from conferences we've attended or group outings as well as some of our conference poster presentations.

Conference pictures
SSI 18
 
 Having lunch...  
 
... the other half (having lunch)  
 
 At the conference dinner  
   
 A bit of sightseeing...  
   
 ... and a group evening out.  

 

Applied Catalysis and Reaction Engineering IChemE-RSC Conference

High-stability, high capacity oxygen carriers: Iron oxide-perovskite hybrid materials for hydrogen production by chemical looping

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Introduction  

Iron oxide has been widely used as an oxygen-carrier for hydrogen production by chemical looping due to its good thermodynamic properties [1-4].  In this process, a carbonaceous fuel, here carbon monoxide, is used to reduce the iron oxide (producing carbon dioxide), then water is used to re-oxidise the iron to its previous state and produce hydrogen.  This is performed in a cyclic manner.  Iron oxide, however, suffers from thermal sintering at high temperatures (>800oC) and as a result loses surface area while particle size increases [5, 6].  Perovskites, such as La0.7Sr0.3FeO3-δ (LSF731), have been suggested as potential candidate oxygen-carrier for hydrogen production due to their excellent oxygen transport properties [7] and offer a solution to this problem.  This work proposes the use of hybrid materials composed of iron oxide clusters embedded in a stable LSF731 matrix.  The perovskite matrix facilitates oxygen transport to the iron oxide clusters while preventing agglomeration.  Two preparation methods were used, mechanical mixing and a modified Pechini method, to obtain hybrid materials with different iron oxide fractions, 11 and 30 wt.%.  Materials prepared by both methods were ultimately pelletized, sintered, crushed and sieved in different ranges for comparison: <40 µm, 40-80 µm, 80-160 µm and >160 µm.

 

     

19th International Conference on Solid State Ionics

 Fe2O3-perovskite materials for hydrogen production using the steam-iron process

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Introduction  

The greenhouse effect of CO2 emissions, mainly coming from the burning of fossils fuels for energy production or transport, is well known. Transport is responsible of one third of the total emissions of this gas to the atmosphere produced in a multiciplity of small distributed sources. The use of H2 in fuel cells, with higher efficiency than conventional engines, is of increasing interest due to its zero-CO2 emissions. Nevertheless, hydrogen is an energy vector that must be produced from a primary energy source. In this way, if hydrogen is used as a CO2-free energy carrier, it must be produced without net realease of CO2, for example from renewable energy sources or from fossil fuels with CO2 cpature and storage. Current industrial H2 production methods are steam methane reforming, partial oxidation and auto-thermal reforming. Each of these processes include expensive separation stages to generate hydrogen of the desired purity. The steam-iron process has been revealed as an efficient process for H2 production with inherent CO2 capture which intrisically require no further purification.

     

Ion-conducting dual-phase membrane for high temperature CO2 separation
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Introduction

The concept of a dual-phase carbonate-electroceramic membrane based on the idea of the molten carbonate fuel cell (MCFC) has been demonstrated recently [1, 2].  The dual-phase system consists of a porous oxygen anion O2- conducting ceramic substrate hosting a guest molten carbonate phase (usually a Li/Na/K carbonate eutectic mixture) infiltrated within the pore network.  Carbon dioxide from the feed gas reacts with oxygen ions supplied by the ionic conducting host membrane to form a carbonate (CO32-) anion in the molten carbonate phase.  The CO32- anion is transported through the molten phase carbonate at high temperatures under a chemical potential gradient and released as gasous CO2 on the permeate side.  The O2- anion is transported back to the feed side membrane by the substrate [1, 2].  A schematic is presented in Figure 2.  In this project, the dual phase membrane was fabricated by yttria stabilized zirconia (8 mol% Y2O3) powder which was mechanically mixed with up to 33 wt% corn starch as a pore former and sintered at 1450 °C. The sintered porous membrane was then infiltrated with a known quantity of a eutectic mixture of; Li2CO3, Na2CO3 and K2CO3 in the molar ratio 51:16:33.

     

The role of sodium surface species on the catalytic, electrocatalytic and electrochemical properties of Pt/YSZ in NOx reduction by propene
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Introduction

Recently studies found that variations in the morphology of a catalyst and the presence of impurities on the catalyst surface  can have a significant impact on the catalyst behaviour. In this work in order to systematically study the role of impurities in electrochemical promotion of catalysis (EPOC) a known amount of sodium is deposited in increasing concentration on top of a nominally ‘clean’ catalyst surface. Previously we have shown that significant amount of Na coverage (approximately  11% Na coverage) on the Pt catalyst may enhance the catalytic activity of C2H4 oxidation. In this study, the influence of sodium surface species in electrochemical promotion of NO reduction by C3H6 is investigated. NO reduction is a reaction of environmental significance. EPOC studies of NO reduction by C3H6 on Pt catalysts were mainly done on those interfaced on alkali ion conductors, while only a few studies were conducted on YSZ, an oxygen ion conductor.

     
 

In-situ characterization of a steam-permeable BCY electrolyte for solid oxide fuel cells
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Introduction

Solid electrolytes which are simultaneously steam permeable, as a result of proton and oxygen ion conduction, could be used to introduce steam in a distributed manner into a working solid oxide fuel cell (SOFC). Such distributed introduction of steam may be beneficial in terms of exposing the cell to lower internal temperature gradients thus improving cell life. For such an approach to be viable it is important to understand the mechanism of steam transport and specifically the nature of the surface sites that are required for water incorporation into the electrolyte as well as water evolution. Such understanding will allow the rational design of steam permeable SOFC.

     

2012 transportNewcastle Seminar: Sustainability in Transport Research

H2 production methods for sustainable transportation
 

Introduction

As hydrogen becomes more important as an energy vector, the need to find inexpensive, less energy intensive and environmentally friendly ways of producing it increases. Current industrial production methods include steam methane reforming, partial oxidation and auto-thermal reforming. Each of these processes include expensive separation stages to generate hydrogen of a desired purity. Two production techniques which intrinsically require no further purification of hydrogen are chemical looping and membranes. Both methods produce hydrogen by splitting water. In chemical looping this is done over a reduced material, whereas in membranes the oxygen partial pressure gradient is used. So that further purification can be avoided the processes must be carefully designed to achieve an low impurity level (CO <50 ppm) for use in fuel cells. In a simple case of using CO as the reducing/oxygen lean gas the only products are CO2, but when other gases are utilised (e.g. CH4), different carbonaceous products can be produced. This increases the number of impurities possible. Results with impurity levels present have been displayed in order to highlight some of the challenges with these techniques: carbon deposition during reduction step and reactive gas break through for chemical looping and membranes respectively.

     

2012 International Symposium on Chemical Reaction Engineering

Reduction kinetics by CO & CO2 mixtures for H2 production via the steam-iron process
 

Introduction

The steam-iron process is a chemical looping cycle which traditionally utilises iron oxide as the oxygen carrier material (OCM). The iron oxide is alternately reduced and oxidised using carbon monoxide as the reducing agent, and steam as the oxidising agent. Water splitting occurs during the oxidation step and can produce pure hydrogen with suitably low CO levels (<50ppm) for use in fuel cells. Air can also be introduced into the cycle to further oxidise the iron oxide (to Fe2O3) providing heat to the system.

There is relatively little information on the reaction kinetics of the steam-iron process, however. Most, if not all, of the work on this process up until now has focussed on reactor inlet conditions only. In terms of reactor design and scale up, the reaction kinetics along the whole reactor bed are important. Thus this work investigates the reaction kinetics along the length of a fixed bed reactor. This is achieved within a differentially operated micro-reactor by simulating the changing conditions along the reactor length by changing the inlet gas feed to include quantities of product gas with the reactant gas.

     

‎2012 Solid State Protonic Conductors 16

Water permeation studies on a BaCe0.8Y 0.2O3-δ membrane reactor
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Introduction

Solid oxide fuel cells (SOFCs) have received a great attention owing to their high energy conversion efficiency, fuel flexibility and low emissions. SOFCs require either an external or internal steam reforming step if they are to be used with hydrocarbon fuels. Internal reforming is more efficient but introduction of all of the water in the fuel cell inlet can lead to severe internal temperature gradients within the fuel cell as the reforming reaction is fast and endothermic. Here we intend to introduce water across the SOFC electrolyte while it is operational as shown in the concept. The distributed water introduction will result in controlled reforming, reduce fuel cell temperature gradients and increased membrane humidification. Y - doped BaCeO3 (BCY) was chosen as the electrolyte since it has recently shown proton and oxide ion conductivity simultaneously.

     

 

2012 7th International Conference of Enviromental Catalysis

The role of Na surface species on EP in a Pt/YSZ system
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Introduction

‎The study is on the role of sodium addition on electrochemical promotion of catalysis in a Pt/YSZ system. Ethylene oxidation and NO reduction by propene are used as probe reactions. It was found in the first instance that sodium addition at low coverage affect the electrocatalytic activity of the system by lowering the catalyst work function, in analogous to the role of electronic promoter species electrochemically supplied during electrochemical promotion (by modifying the binding strength of adsorbed gases e.g. oxygen adsorbed from the gas phase). At high sodium coverage it appears that sodium increases the catalytic activity possibly by enhancing or creating new sites for, oxygen adsorption, oxygen diffusion and/or oxygen storage. At very high sodium coverage sodium poisoning occurs and the selectivity of NO oxidation to NO2 is higher than NO reduction to N2 or to N2O.

     

 

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