Visit to Johnson Matthey Technology Centre
Johnson Matthey is an international speciality chemicals company, founded almost 200 years ago in London. Technology leadership forms the basis of their strategy to deliver superior long term growth.
The company began in 1817 when Percival Johnson set up business as a gold assayer in London.
1792 – 1866
Over the years he had many partners but in 1851 George Matthey joined the company to form Johnson and Matthey.
1825 – 1913
The link below will give some information about George Matthey
In 1860 Percival Norton Johnson retired. George Matthey, John Sellon and Edward Matthey form a partnership called Johnson Matthey and Company.
The Johnson Matthey Technology Centre (JMTC) is the group’s central resource for longer-term research. The main facility is located at Sonning Common in the UK with a further technology centre at Billingham, UK and smaller units in Savannah (USA) and Pretoria (South Africa).
Johnson Matthey is great supporter of research work and gives its staff a high level of support.
One of the areas that Johnson Matthey is working on is environmental issues.
Other areas of interest include research into:
Light duty e.g. cars;
Heavy duty e.g. diesel;
The company operates all over the world.
Johnson Matthey intends continuing work in core science but specialising in specific areas including sustainability.
They have a growing network of interests such as microscopy.
Johnson Matthey people and activities
Technical competencies include organic, physical and inorganic chemistry, electrochemistry, chemical engineering and materials science. I asked if they took on physics graduates/PhD and the answer was yes if they had an appropriate specialism such as optical properties.
Projects that they are working on include the control of ethylene to keep fruit such as bananas fresh for longer.
They also work with others
Above is a link for water purification using a ceramic polymer
Johnson Matthey and fuel cells
The company has a long association with this technology.
Sir William Robert Grove PC QC FRS (11 July 1811 – 1 August 1896) was a Welsh judge and physical scientist. He anticipated the general theory of the conservation of energy, and was a pioneer of fuel cell technology.
The above centre picture is a diagram of Grove’s 1839 gas voltaic battery and the picture on the right is his 1842 fuel cell.
In 1842, Grove developed the first fuel cell (which he called the gas voltaic battery), which produced electrical energy by combining hydrogen and oxygen, and described it using his correlation theory.
A fuel cell transforms the chemical energy liberated during the electrochemical reaction of a fuel such as hydrogen and an oxidant, usually oxygen, to electrical energy, as opposed to the direct combustion of hydrogen and oxygen gases to produce thermal energy.
What is a fuel cell?
A fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Current is drawn directly from the system. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used. Fuel cells are different from batteries in that they require a constant source of fuel and oxygen/air to sustain the chemical reaction; however, fuel cells can produce electricity continually for as long as these inputs are supplied.
There are many types of fuel cells, but they all consist of an anode (negative side), a cathode (positive side) and an electrolyte that allows charges to move between the two sides of the fuel cell. Electrons are drawn from the anode to the cathode through an external circuit, producing direct current electricity.
The above picture shows a section of a proton-conducting fuel cell. The oxygen can be taken directly from the air.
Why use a fuel cell?
Fuel cells offer a variety of benefits compared to traditional power generators. They are generally more fuel-efficient, operate with very little noise and produce no harmful emissions at point of use (fuel cells that use renewable hydrogen as a fuel do not generate CO2 in the energy chain). They have no moving parts and are thus easy to maintain. In addition to electrical power, they produce high-quality heat which can be used for heating (or to drive refrigeration cycles for cooling), so improving the overall efficiency of fuel use.
Since fuel cells and batteries can generate useful power when all components of the system are at the same temperature (T = TH = TC), they are clearly not limited by Carnot’s theorem, which states that no power can be generated when TH = TC. This is because Carnot’s theorem applies to engines converting thermal energy to work, whereas fuel cells and batteries instead convert chemical energy to work. Nevertheless, the second law of thermodynamics still provides restrictions on fuel cell and battery energy conversion.
TC is the absolute temperature of the cold reservoir; TH is the absolute temperature of the hot reservoir,
The formula for this maximum efficiency is
which equals zero for a fuel cell.
Carnot’s theorem, developed in 1824 by Nicolas Léonard Sadi Carnot, also called Carnot’s rule is a principle that specifies limits on the maximum efficiency any heat engine can obtain, which thus solely depends on the difference between the hot and cold temperature reservoirs.
A fuel Cell Stack consists of individual fuel cells connected in series. Fuel cells are stacked to increase the voltage and therefore the power (current x voltage).
Types of fuel cell
Polymer Electrolyte Membrane (PEM) Fuel Cells
Direct Methanol Fuel Cells
Alkaline Fuel Cells
Phosphoric Acid Fuel Cells
Molten Carbonate Fuel Cells
Solid Oxide Fuel Cells
Regenerative Fuel Cells
Fuel cell markets required for stationary power, transportation and portable power supplies.
Direct-methanol fuel cells or DMFCs are a subcategory of proton-exchange fuel cells in which methanol is used as the fuel. Their main advantage is the ease of transport of methanol, and they contain an energy-dense yet reasonably stable liquid at all environmental conditions.
They may not become popular because their efficiency is quite low which maybe why some technology is switching to hydrogen for small, portable appliactions.
Fuel cell fork lift truck
Hydrogen-powered vehicles have been out of the spotlight for years, but they’re about to make a surprising comeback. Toyota says it will unveil a hydrogen fuel-cell-powered sedan later this year that will go on sale in 2015; several other automakers, meanwhile, have announced partnerships to commercialize the technology (see “Ford, Daimler, and Nissan Commit to Fuel Cells”), including GM and Honda, which announced such a collaboration this week.
A fuel cell wins because it does not produce carbon dioxide at the exhaust. Overall, the CO2 emission depends on where the hydrogen comes from. Another advantage is that a fuel cell doesn’t have many moving parts.
Hyundai ix35 Fuel Cell model
Honda FCX Clarity Toyota FCV-R fuel cell vehicle
Compressed hydrogen in hydrogen tanks at 700MPa is used for hydrogen in vehicles. Car manufacturers such as Honda or Nissan have been developing this.
Daimler Chrysler research into fuel cells.
The link below gives a comparison between hydrogen fuel and oil based fuel.
Phosphoric acid fuel cells have been considered for use in cars, but the power density tends to be too low.
Phosphoric acid fuel cells (PAFC) are a type of fuel cell that uses liquid phosphoric acid as an electrolyte. A distinct advantage of these units is that they run at about 180°C and so CO poisoning of the platinum electro-catalyst in the anode is avoided. The lower power density and high temperature make them suitable for stationary combined heat and power applications (CHP).
Fuel cell cars are expected to have the same lifespan as a petrol engine car.
Both X ray diffraction and transmission electron microscopy are used to investigate the surfaces of materials. The information from all the techniques used are brought together.
X ray diffraction can give information about crystal phases and size present. It can even tell you what sort of crystal you have.
Transmission electron microscopy (TEM) is a microscopy technique whereby a beam of electrons is transmitted through an ultra-thin specimen, interacting with the specimen as it passes through. An image is formed from the interaction of the electrons transmitted through the specimen; the image is magnified and focused onto an imaging device, such as a fluorescent screen, on a layer of photographic film, or to be detected by a sensor such as a CCD camera.
A “laser” of electrons through the sample are scattered and a computer forms an image.
Below are images of a catalyst layer at increasingly higher magnifications to capture the carbon (C) particles. Since these particles are ~100 nm and are not well-defined, high magnification was necessary for imaging. The Platinum (Pt) particles themselves are too small (~5 nm) and too poorly defined to image well in a conventional scanning electron microscope.
Left – Catalyst layer surface at 20,000x; the myriad small spheres are C particles
Right – Same specimen at 100,000x; a few C particles have been highlighted
A scanning electron microscope (SEM) is a type of electron microscope that produces images of a sample by scanning it with a focused beam of electrons. The electrons interact with atoms in the sample, producing various signals that can be detected and that contain information about the sample’s surface topography and composition. The electron beam is generally scanned in a raster scan pattern, and the beam’s position is combined with the detected signal to produce an image. SEMs can achieve resolution better than 1 nanometer. Specimens can be observed in high vacuum, in low vacuum, and (in environmental SEM) in wet conditions.
Generally, the image resolution of an SEM is about an order of magnitude poorer than that of a TEM. However, because the SEM image relies on surface processes rather than transmission, it is able to image bulk samples up to many centimetres in size and (depending on instrument design and settings) has a great depth of field, and so can produce images that are good representations of the three-dimensional shape of the sample. Another advantage of SEM is its variety called environmental scanning electron microscope (ESEM) can produce images of sufficient quality and resolution with the samples being wet or contained in low vacuum or gas.
The superior resolution of the TEM allows direct imaging of the Platinum (Pt) nanoparticles in the fuels cell membrane.
Below is a TEM Image of Catalyst Layer-Ionomer Interface at 500,000x
Energy-dispersive X-ray spectroscopy (EDS, EDX, or XEDS) is an analytical technique used for the elemental analysis or chemical characterization of a sample.
A high-energy beam of charged particles such as electrons or protons, or a beam of X-rays, is focused into the sample being studied. Electron beam excitation is used in electron microscopes, scanning electron microscopes (SEM) and scanning transmission electron microscopes (STEM).
Above left is a scanning electron microscope image of carbon nanotube bundles. Above centre is an image of twenty carbon nanotubes. Each one is 5 microns. Above right is an image of a single carbon nanotube.
A single nanotube is a layer of rolled up graphene.
Below is a conceptual diagram of single-walled carbon nanotube (SWCNT) (A) and multiwalled carbon nanotube (MWCNT) (B) delivery systems showing typical dimensions of length, width, and separation distance between graphene layers in MWCNTs.
Electron micrograph and atomistic model (bottom right) of a highly oxygen-activating platinum-nickel catalyst particle. Its diameter is approximately ten thousand times smaller than the diameter of a human hair. Red spheres represent platinum atoms and green spheres represent nickel atoms. One of the properties of such octahedra is that most surface atoms have the same geometric arrangement. The micrograph was taken at the PICO microscope. Credit: Source: Forschungszentrum Jülich/TU Berlin
Raney nickel is used as a reagent and as a catalyst in organic chemistry. It was developed in 1926 by American engineer Murray Raney for the hydrogenation of vegetable oils.
Zeolites are microporous, aluminosilicate minerals commonly used as commercial adsorbents and they are widely used in industry as catalysts.
They are ideal catalytic materials because they have nanostructure on the same scale as the molecules that react within their pores. Their nanostructure is a function of the conditions under which they are created, and because of the molecular scale of the catalytic surfaces, their macroscopic properties are thus a function of those same conditions.
Their porous structure can accommodate a wide variety of cations and confine molecules in small spaces, which causes changes in their structure and reactivity. They are commonly called a molecular sieve as this refers to a particular property of these materials, i.e., the ability to selectively sort molecules based primarily on a size exclusion process. This is due to a very regular pore structure of molecular dimensions. The maximum size of the molecular or ionic species that can enter the pores of a zeolite is controlled by the dimensions of the channels.
A catalyst is a chemical that increases the rate of a reaction without being changed. The properties of a zeolite as a catalyst can be changed by the different chemicals it absorbs.
The above images show scanning electron micrograph of Na-zeolitic tuff (a) and Fe-zeolitic tuff (b).
The image below shows more zeolites containing catalysts.
The above picture shows a TEM image of fuel cell catalyst. The black specks are the catalyst particles ﬁnely divided over a carbon support. The structure clearly has a large surface area. (Reproduced by kind permission of Johnson Matthey Plc.)
Heinrich Rudolf Hertz discovered the photoelectric effect, in 1887, that was explained in 1905 by Albert Einstein (Nobel Prize in Physics 1921).
X-ray photoelectron spectroscopy (XPS) is a quantitative spectroscopic technique that measures the elemental composition, empirical formula, chemical state and electronic state of the elements that exist within a material. http://www.princeton.edu/~surfsci/escalab.htm
XPS is a surface chemical analysis technique that can be used to analyse the surface chemistry of a material in its “as received” state, or after some treatment, for example: fracturing, cutting or scraping in air or UHV to expose the bulk chemistry, ion beam etching to clean off some of the surface contamination, exposure to heat to study the changes due to heating, exposure to reactive gases or solutions, exposure to ion beam implant, exposure to ultraviolet light.
The above image shows a rough schematic of XPS physics. XPS spectra are obtained by irradiating a material with a beam of X-rays while simultaneously measuring the kinetic energy and number of electrons that escape from the top 1 to 10 nm of the material being analysed. XPS requires ultra-high vacuum (UHV) conditions. The energy in and energy out are measured and the missing energy gives you information about the surface.
Electrons cannot pass very far into a material, probably just 1nm. This means that only the first few layers of the surface of a catalyst can be investigated by electrons. The process gives a quantitative surface analysis and an average chemical analysis.
Scientists design a surface and the surface scientist will disprove or prove the efficacy of the surface.
Surface enhanced Raman spectroscopy or surface enhanced Raman scattering (SERS) is a surface-sensitive technique that enhances Raman scattering by molecules adsorbed on rough metal surfaces or by nanostructures such as plasmonic-magnetic silica nanotubes. The enhancement factor can be as much as 1010 to 1011, which means the technique may detect single molecules.
The sample being investigated is kept in a vacuum with a pressure of 10-8mB and there are 10-10 million collisions per second.
Fuel cell research at Johnson Matthey
Hydrogen peroxide can be used as an alternative oxidant for PEM based fuel cells in any application which can see a limited amount of free convection air. However it can form inside fuel cells and cause problems.
Context of fuel cell research
The aim is improvement of the membrane electrode assembly and carbon fibre paper for improved performance.
A single fuel cell is only capable of producing about 1 volt, so typical fuel cell designs link together many individual cells to form a “stack” to produce a more useful voltage. A fuel cell stack can be configured with many groups of cells in series and parallel connections to further tailor the voltage, current, and power. The number of individual cells contained within one stack is typically greater than 50 and varies significantly with stack design.
Some stacks are very compact as the bipolar plates can be quite thin, however the bigger the area the bigger the current. 1cm2 can produce currents as high as 2A. There is a low internal resistance, low voltage (few hundred mV) and a high current.
Bipolar Plates or Separator Plates are conductive plates in a fuel cell stack that act as an anode for one cell and a cathode for the adjacent cell. The plates may be made of metal or a conductive polymer (which may be a carbon-filled composite). The plates usually incorporate flow channels for the fluid feeds and may also contain conduits for heat transfer.
A membrane electrode assembly (MEA) is an assembled unit comprising a proton exchange membrane (PEM) or alkali anion exchange membrane (AAEM), catalyst layers and gas diffusion electrodes.
In the case of a PEMFC, the MEA is the structure consisting of an electrolyte (proton-exchange membrane) with surfaces coated with catalyst / carbon / binder layers and sandwiched by two microporous conductive layers, which are supported on carbon fibre paper, or cloth, and act as gas diffusion layers and current collectors.
Diagrams above show electro-chemical reaction diagram of PEM MEA on the left and transport of Gases, H+ and e- in PEMFC on the right.
The PEM is sandwiched between two electrodes which have the catalyst layers in intimate contact with the PEM. The electrodes are electrically insulated from each other by the PEM. These two electrodes make up the anode and cathode respectively.
The PEM is a fluoropolymer (PFSA) proton permeable but electrical insulator barrier. This barrier allows the transport of the protons from the anode to the cathode through the membrane but forces the electrons to travel around a conductive path to the cathode. Companies such as DuPont and Dow produce PEMs. DuPont’s PEM offering can be found under the trade name Nafion.
Water electrolysis is the conversion of electrical energy into chemical energy in the form of hydrogen with oxygen as a useful by-product. Some of the electrical energy is later recovered by reacting hydrogen with oxygen in a fuel cell or combustion engine. The conversion of electrical energy to chemical energy is done in an electrolyser via:
Electrolysers produce high purity hydrogen, which is ideal for fuelling a fuel cell car. However, a car will still need a conventional battery for load levelling (a method for reducing the fluctuations in demand for current on the fuel cell) and to prevent excessive cycling that can reduce the stability of the platinum catalysts. The conventional battery is a buffer. It is expected that the conventional lead-acid battery will be replaced by a circa 50V lithium battery.
Fuel cell membrane
To function, the membrane must conduct hydrogen ions (protons) but not electrons as this would in effect “short circuit” the fuel cell. The membrane must also not allow either gas to pass to the other side of the cell, a problem known as gas crossover. Finally, the membrane must be resistant to the reducing environment at the anode as well as the harsh oxidative environment at the cathode.
Gas diffusion electrodes (GDE) are electrodes with a conjunction of a solid, liquid and gaseous interface, and an electrical conducting catalyst supporting an electrochemical reaction between the liquid and the gaseous phase. They are often carbon fibre paper, which can’t be folded, or sometimes carbon fibre cloth, which is more flexible.
GDEs are used in fuel cells, where oxygen and hydrogen react at the gas diffusion electrodes, to form water, while converting the chemical bond energy into electrical energy. Usually the catalyst is fixed in a porous foil, so that the liquid and the gas can interact. Besides these wetting characteristics, the gas diffusion electrode has, of course, to offer an optimal electric conductivity, in order to enable an electron transport with low ohmic resistance.
Principle of the gas diffusion electrode
Since about 1970, PTFE is used to produce an electrode having both hydrophilic and hydrophobic properties whilst being chemically stable and having useful binding properties. This means that, in places with a high proportion of PTFE, no electrolyte can penetrate the pore system and vice versa. In that case the catalyst itself should be non-hydrophobic.
Nafion is a sulfonated tetrafluoroethylene based fluoropolymer-copolymer discovered in the late 1960s by Walther Grot of DuPont. It is the first of a class of synthetic polymers with ionic properties which are called ionomers. Nafion’s unique ionic properties are a result of incorporating perfluorovinyl ether groups terminated with sulfonate groups onto a tetrafluoroethylene (Teflon) backbone. Nafion has received a considerable amount of attention as a proton conductor for proton exchange membrane (PEM) fuel cells because of its excellent thermal and mechanical stability.
The chemical basis of Nafion’s superior conductive properties remains a focus of research. Protons on the SO3H (sulphonic acid) groups “hop” from one acid site to another (water needs to be present). Pores allow movement of cations but the membranes do not conduct anions or electrons. Nafion can be manufactured with various cationic conductivities.
The above picture shows the chemical structure and “water channel” model of Nafion membrane.
http://pubs.acs.org/doi/abs/10.1021/cm401445hThe catalyst layer
The material is granular and hydrophobic. It is possible to just see the proton conducting.
Improving MEA performance
Optimise the size and shape of the platinum particles. Decreasing the particles’ size alone increases the total surface area of catalyst available to participate in reactions per volume of platinum used, but recent studies have demonstrated additional ways to make further improvements to catalytic performance. For example, one study reports that high-index facets of platinum nanoparticles provide a greater density of reactive sites for oxygen reduction than typical platinum nanoparticles. This means the amount of platinum used can be reduced.
Increase the catalytic activity of platinum can be done by alloying it with other metals.
Improve catalyst performance by reducing its sensitivity to impurities in the fuel source, especially carbon monoxide (CO).
Engineer new non-degrading membranes in the materials.
Prevent the platinum layer from dissolving and moving about.
Design a fuel cell that can operate in reverse as an electrolyser, then electricity can be used to convert the water back into hydrogen and oxygen.
Use core-shell electrocatalysts for fuel cells. These have the advantages of a high utilization of Platinum and the modification of its electronic structures toward enhancement of the activity. They have 3.5 to 5 times the activity of pure platinum nanoparticles at a fraction of the cost. The platinum also has some protection.
Atomic resolution images of the palladium-colbalt nanoparticle, before platinum deposition.
Hydrogen storage solutions by using reversible metal hydrides, more tolerant catalysts and reduced costs.
1) Portable fuel cell that can be charged up. It measures 8 x 12 cm.
Portable power systems that use fuel cells, can be used in the leisure sector (i.e. RV’s, Cabins, Marine), the industrial sector (i.e. power for remote locations including gas/oil wellsites, communication towers, security, weather stations etc.), or in the military sector. SFC Energy is German manufacturer of Direct methanol fuel cells, which uses their fuel cell for a variety of portable power systems. Ensol Systems Inc. is an integrator of portable power systems, using the SFC Energy DMFC.
Direct-methanol fuel cells or DMFCs are a subcategory of proton-exchange fuel cells in which methanol is used as the fuel. Their main advantage is the ease of transport of methanol, an energy-dense yet reasonably stable liquid at all environmental conditions.
Toshiba has created a 10W methanol fuel cell. In 2008 permission was given to allow approved methanol fuel cells to be carried on board aeroplanes.
A lot of recent development has focussed on hydrogen for small fuel cells rather than methanol.
Horizon has developed a process of absorbing hydrogen in a reversible metal hydride. This is completely safe as it is non-flammable.
3) Smart fuel cell
Smart Fuel Cells, offer several advantages over older fuel cell and battery technology. For one thing, they’re up to 80 percent lighter, according to the company. Another advantage is that soldiers can carry replacement fuel cartridges to keep the cell going. Smart Fuel Cells, like most fuel cells, also operate very quietly, an important feature for covert military operations. Unlike many other fuel cells, Smart Fuel Cells operate at a fairly low temperature, making them suitable for carrying in both standard issue military vests and military vehicles alike.
Methanol cartridges seem safe to handle and can produce a power of 150W. As well as military uses it can be used in caravans and motorhomes when they are stationary. They can be used to power TVs and pumps.
Of course, methanol also has some downsides. For one thing, it’s not as readily available as some other types of fuel. The military commonly uses a kerosene-based fuel called JP-8, for instance, though fuel cells using JP-8 currently produce dangerous emissions, making methanol the safer, if not cheaper, choice. Methanol fuel cells are also less efficient than some other fuel cell technologies like hydrogen-fuelled polymer exchange membrane fuel cells (PEMFCs), though they still offer better power density than alternatives like lead acid batteries.
3) 1KW “air-green” fuel cell is used as the back-up power source for mobile telephone masts. An off-grid cell site is not connected to the public electrical grid. Usually the system is off-the-grid because of difficult access or lack of infrastructure. Fuel cell systems are added to critical cell sites to provide emergency power. They are low maintenance and are particularly useful in developing countries.
The above picture shows an off-grid power system for a cellular site.
3) 60KW fuel cell car cooled by glycol.
Fuel cell is a promising power source for vehicles because of its advantages such as high efficiency and no pollutant of emissions.
4) South Korea has set up 400 kW UTC Power fuel cell power plant.
A protonic ceramic fuel cell or PCFC is a fuel cell based on a solid ceramic electrolyte material that exhibits high protonic conductivity at elevated temperatures.