Energy projects within MESA+
Within the Strategic Research Orientation various topics on energy-related materials science are being studied.
· Energy efficient electronics
· Energy efficient processes
Several examples of research projects are shown below. The complete overview of energy projects within MESA+ is listed here.
Self-assembled photocatalytic nanowires
Nanowires are currently of high interest due to their unusual properties at the nanoscale and a large range of potential applications, including photocatalytic splitting of water. A scientific and technological bottleneck is that current nanowire fabrication methods do not allow for a straightforward variation of core materials nor of attached catalysts. Therefore, this research aims for the development of a versatile fabrication method for functionalized photocatalytic nanowires by using self-assembly. The photocatalytic nanowires separate solar energy into electrons and holes, which are used by the self-assembled catalysts to facilitate the fuel formation reactions. Upon synthesis of the nanowires, their ends are functionalized differently by applying a local surface chemistry. These surface chemistries allow the selective self-assembly of two different catalysts (or one catalyst and a mediator) onto the nanowires. The general applicability of both the nanowire synthesis and their functionalization by self-assembly allows a variety of catalysts to be assembled, and should thus lead to the first truly versatile fabrication method of photocatalytic nanowires.
PhD student: Janneke Veerbeek, Supervisor: prof.dr. Jurriaan Huskens (MnF/TNW) More information.
Nanostructured solar-to-fuel devices
In order to produce fuel from sunlight, oxygen evolution by oxidation of water needs to be coupled to the reduction of protons. This project focuses on the performance efficiency of integrated systems which encompass all necessary parts of a complete artificial photosynthetic system, and in particular on the effect of nanostructuring of elements of the system on the coupling between the parts and the overall performance.
Using Si p/n junctions as the light-harvesting unit, the emphasis lies on the 2D and 3D structuring of Si p/n junctions, and electrocatalytic moieties will be deposited onto these. Performance will be investigated with optical, electrical and analytical-chemical techniques. This approach will be developed into a device layout, which will consist of a microfluidic system, which also allows product separation. A comparison of the two systems will be made at the device level to provide a clear reference framework for future valorization.
PhD students: Rick Elbersen and Sun-Young Park, Supervisors: prof. dr. Jurriaan Huskens (MnF/TNW), prof dr. Han Gardeniers (MCS/TNW), prof dr. Guido Mul (PCS/TNW), prof. dr. Jennifer Herek (OS/TNW)
Visible-light induced water-splitting on a chip
A direct way to produce hydrogen and oxygen from water is by photocatalysis. Following a two step z-scheme process, it is possible to use the visible part of the light spectra. In this process two types of catalytic particles needs sunlight to become active and one will take care for the oxygen production and the other for the hydrogen production. Between the catalytic particles there is an exchange of electrons and H+. Results in the literature show a low efficiency for this method. By introducing a structured metallic divider the goal is to separate the hydrogen and oxygen catalysts, and take care for a low conduction path for the electrons. This should contribute to an increased efficiency of the photocatalytic process. The metallic plate also divides the system in two compartments, which results in a separated oxygen and hydrogen production.
PhD student: Michel Zoontjes, Supervisors: prof. dr. Wilfred van der Wiel (NE/EWI), prof dr. Guido Mul (PCS/TNW), dr. Mark Huijben (SRO MESA+)
Nanowires of arbitrary size, composition and architecture, e.g. striped or core-shell, can be realized by electrodeposition in straight nanopores. This project targets the development of photocatalytically active oxide-based nanowires that are able to transform chemical transformations in liquids under illumination in UV or visible light. Examples are the production of hydrogen from water or methanol using TiO2 or ZnO containing wires. The focus in the project is on the optimization of the nanowire architecture to improve the efficiency of the transformation process.
PhD student: Wouter Maijenburg, Supervisor: dr. André ten Elshof (IMS/TNW)
Efficient energy harvesting by nanostructured thermoelectric materials
To what extent can the heat-to-electricity conversion efficiency be increased by fabricating high-quality oxide superlattices, i.e., is it possible to reduce the thermal conductivity through optimized phonon scattering by confinement in oxide nanostructures? Here, the fabrication of high quality interfaces is particularly challenging, because atomic interdiffusion and interface defects will have significant influence on phonon scattering and charge carrier transport. New developments in atomically controlled thin film growth enable us to design and fabricate such novel artificial oxide materials.
PhD student: Peter Brinks, Supervisor: dr. Mark Huijben (IMS/TNW)
Thin film electrolyte manufacturing technology for SOFC
The cost of the state-of-the-art SOFC technology remains too high to compete with entrenched power generation technologies. As a consequence there is an increasing interest over the last ten years in the development of metal supported SOFC (MSC). The main technological hurdle for the introduction of the MSC is the cost efficient depositing of a defect free thin film electrolyte layer on such metal support. Novel cheap and easily upscalable technology concepts for thin film electrolytes for solid oxide fuel cells (SOFC) and solid oxide electrolyser cells (SOEC) on porous substrates are targeted in this project. Upscalable wet-chemical routes and laser deposition routes are being developed.
PhD student: Sjoerd Veldhuis, Supervisor: dr. André ten Elshof (IMS/TNW)
Robust Ceramic Anodes for it-SOFC
The main goal of current research is to lower the SOFC operation temperature from 900-1000ºC to around 600ºC, i.e. the intermediate temperature fuel cell (it-SOFC). The state of the art anode is a Nickel/Yttria Stabilized Zirconia cermet (Ni/YSZ). Although this cermet is the most efficient anode, it suffers from several drawbacks which leads to short lifetime. Nevertheless, it has been shown that it is possible to use an all-ceramic anode. It is, however, difficult to obtain all objectives (good electronic and ionic conductivity and catalytic properties) in one material. Hence, the use of two different materials in a porous composite structure may be a promising route.
Thus, the objective is to identify ceramic materials and to develop composites with excellent anode properties for operation at ~600°C in it-SOFCs applications. The aim is to create synergy between combinations of ceramic oxides with different properties (ionic conductivity, catalytic activity versus good electronic conductivity), or even between metallic structures and mixed (predominantly ionic) conductive oxides, which are stable under working conditions.
A derived objective is to gain insight in materials properties of oxides in a highly reducing regime (e.g. ~10-12 – 10-16 Pa) with which the optimization of the anode microstructures can be facilitated.
PhD Student: Gerard Cadafalch i Gázquez. Supervisor: Dr. Bernard Boukamp
A miniaturised solid-acid fuel cell
We propose an innovative fuel cell that works at temperatures between 150 and 250C, in which range currently no practical fuel cell exists. The innovation deals with the use of a new thin film of solid-acid in a fuel cell that acts as a proton conductive membrane, sandwiched between two non-porous thin-film palladium or palladium-alloyed electrodes. Representative members of the targeted solid-acids include CsHSO4 and Rb3H(SeO4)2, while other compositions with different oxyanion groups (PO4) are possible. The primary objectives of the proposed research are to study thermally stable proton-conducting electrolytes based upon solid-acid compounds, and to explore the potential for utilizing them in a novel design of a miniaturised fuel cell operating at medium temperature. Materials properties, deposition techniques and fabrication technology of the membrane assembly will form the core of the project.
PhD student: Sandeep Unnikrishnan, Supervisor: dr. Henri Jansen (TST/EWI)
Growing a solar cell directly on a CMOS chip
For wireless autonomous microsystems where batteries are not an option, e.g. because of the long lifetime requirement, energy harvesting is considered as one good approach to deliver power to the system. In this STW-funded project we study integration of a solar cell on a chip by “above-IC” CMOS post-processing. The technological challenge is to integrate a photovoltaic energy scavenging component without compromising the chip’s performance. Thin-film solar cell technology is mature, utilizes low-temperature process steps, and is well optimized for high yield at low cost. If we can combine this thin-film technology with standard CMOS, a small system can harvest a lot of power. A good choice of thin-film technology can even lead to appreciable power generation at indoor light conditions, competitive with the best mechanical harvesters to date.
PhD student: Jiwu Lu, Supervisor: dr. A.Y. Kovalgin (SC/EWI)
Photo-active nanostructured oxides for solar applications
New concepts for photovoltaic and photocatalytic cells with improved efficiency will require novel nanostructured and nanopatterned photo-active metal oxide-based materials, like zinc oxide ZnO or titania TiO2. The emphasis in these projects lies on the control over the oxide nanostructure and the functionalization of surfaces on nanometer-scale. In particular the development of low-dimensional oxides and nanopatterned surfaces, to enable the development of miniaturized technologies for photovoltaics, is targeted.
PhD students: Antony George, Suresh Kumar, Supervisor: dr. André ten Elshof (IMS/TNW)
Piezoelectric thin film for energy harvesting device
Piezoelectric thin film is a chosen material for energy harvesting device, which offers a number of advantages in these systems, due to its high piezoelectric coefficients, high power output density and relatively low epsilon. Pb(Zr,Ti)O3 (PZT) was used for its good piezoelectric properties and being well controlled by Pulsed laser deposition (PLD) technique. A new reliable technique is used to integrated PZT piezoelectric thin film into micro-electromechanical system for harvesting usable electrical energy during mechanical vibration. For making a better harvesting device, the figure of merit is vital to achieve a higher piezoelectric voltage in thin film.
PhD student: Xin Wan, Supervisor: prof. dr. Guus Rijnders (IMS/TNW)
Energy from streaming potential using nanotechnology
This project is aimed at the development of methods and devices to produce electrochemical energy from streaming water. When liquid water is pumped through a porous medium, a streaming potential and a streaming current are generated because the liquid drags along ions close to the wall. Recent theoretical work has indicated that very high conversion efficiencies from the mechanical to the electrical domain can be obtained from this process. In order to obtain such efficiencies, our aim is to investigate and develop micromachined porous membranes with nanosized pores.
PhD students: Yanbo Xie & Trieu Nguyen, Supervisor: dr. Jan Eijkel (BIOS/EWI)
Microporous hybrid membranes and materials
Around the globe, a large amount of energy is consumed by industrial separation processes, which involves oil refinery and purification of waste water. Most separation processes involve distillation, which is a rather energy inefficient technique. With the use of membrane techniques, such as pervaporation, reverse osmosis and nanofiltration, we could potentially save 2% of the total world energy consumption. In the current project, a very promising novel class of hybrid organosilica membranes with high hydrothermal stability and fracture resistance are developed.
PhD student: Rogier Besselink, Supervisor: dr. André ten Elshof (IMS/TNW)
Rock-on-a-Chip: Micro- and Nanofluidics for Enhanced-Oil-Recovery
The Physics of Complex Fluids group has a major activity in collaboration with the oil company BP. The goal of the project is to improve the understanding of the physico-chemical processes governing the efficiency of oil recovery on scales ranging from the molecular level to the level of microscopic pores in the rock. Micro- and nanofluidic devices are used as model systems that allow for a detailed characterization e.g. of two-phase flows on the microscale and of the interaction forces of various constituent of the oil with solid surfaces. Physically, these processes involve questions of emulsification, contact line motion, self-assembly at solid-liquid and at liquid-liquid (oil-water) interfaces, electrostatic interactions and ion-specific effects.
The ultimate economic goal of the project is to increase the efficiency of the oil recovery process. Every percent of increase in the total recovery rate yields additional oil for the entire mankind for approximately one year at current consumption.
PhD students and PDs (jointly MESA+ & Impact): Rielle de Ruiter, Jung Min Oh, Willem Tjerkstra, Daniel Ebeling, Agata Brzozowska.
Supervisors: dr. H.T.M. van den Ende, dr. M.H.G. Duits, prof. dr. F. Mugele (PCF/TNW)
This project aims to demonstrate that high reaction selectivity at high conversion is possible for reactions that traditionally do not give reasonable yields because of non-selective, consecutive reactions. The proposed system of study is the direct production of hydroxylamine from ammonia via partial oxidation, which is a much more energy and material saving process compared to multi-step, multi-process production routes. To achieve high reaction selectivity and high conversion, a multiplexed reactor comprising of reactant and product separation membranes is developed. The membrane functionalities must be able to selectively introduce oxygen into the reactant stream via the utilization of a porous, hydrophobic gas liquid contacting membrane, while a second membrane removes hydroxylamine from each microchannel. Ion concentration polarization due to an electrical current through a partially ion-selective membrane is a novel, fundamental transport mechanism, and it can be also an effective method for the separation of hydroxylamine from ammonia.
PhD student: Elif Karatay, Supervisor: prof. Rob Lammertink (SFI/TNW)
Tailored oxide nanoparticles for highly reactive hydroxyl species
The continuous depletion of fossil fuels has necessitated to look for alternative ways to generate hydrogen (H2), which finds its application in fuel cells. Among many, generation of H2 by steam reforming of bio-oil seems an attractive option. The key hindrance in this scheme is the rapid deactivation of catalysts (noble metals on inorganic oxides like ceria (CeO2)) by the carbonaceous species formed during the reaction. Steam reforming combined with gasification of coke in the presence of H2O is conceptually a promising alternative to generate H2 from bio-oil. It is reported that H2O is able to regenerate hydroxyl groups on oxides like ceria, which increases H2 yield and catalyst lifetime. It is also observed that coke gasification occurs on structural defects (low-coordination sites). The goal of this project is to determine structure – performance relationships: 1) the influence of the oxide surface on water dissociation activity and 2) the reactivity of different types of surface hydroxyls towards model coke compounds.
PhD student: Shilpa Agarwal, Supervisor: Dr. Barbara Mojet (CPM/TNW)
The list will be completed soon.