Research

Sustainable Hydrogen Innovation and Technology

I have many research interests, however the main focus tends to circulate around a central concept which is that of “Hydrogen as an Energy Vector”.  With this in mind my research has branched out into a plethora of different directions and many of my skills and experience has been utilised for different applications.

TiO2 photocatalysts – biphasic composite nanoparticles

Fig 1TiO2 has for many years been the pinnacle of photocatalytic research.  Doped TiO2 has shown much promise in applications with wide ranging consequence.  Another source of interest is in pure TiO2 but using the synergistic relationship between the different crystal structures.  Mixtures of both anatase and rutile have shown promise and are indeed the main composition of the commercial P25.  My new synthetic procedures allows for the production of bi-phasic nanoparticles.  Single particles consisting of half anatase and half rutile. These nanoparticles have allowed some interesting measurements to be carried out and helped to answer one of the big questions of semiconductor photocatalysis.  This is regarding the band alignment in a composite system of Anatase and Rutile.  Our Nature Materials paper on the revision of the band alignments of anatase and rutile we showed how this works.

Renewable Energy Storage as Hydrogen Gas

elecseawater

One of grand challenges of the 21st century is to move our energy supply from fossil fuels to renewable.  Incorporated into this is the need to store large quantities of renewable energy so that we can utilise it “On Demand”. Traditional energy demand does not correlate with the strength of the wind or the position of the sun so in order to achieve “On Demand” energy we need some way of storing the energy in times of plenty in order to use it in times of deficit.

Hydrogen gas is the perfect energy vector for the storage of energy from renewable supplies as it can be produced, stored and used when the energy is needed again. There is much technology in and around this sector that I am working on both as a lecturer and as a member of the H2-NRG team to achieve this goal.

 Proton Pumping for the Hydrogen Economy

Proton PumpThe use of proton pumps to remove pure hydrogen from a mixture of gasses allows for the recovery of “Green” Hydrogen. It is also possible that the increase in efficiency in producing mixed hydrogen and oxygen from water using a simple electrolysis process may balance out the energy requirement for separation.  This increase in efficiency and decrease in cost associated with design of water splitting device manufacture could make a two step process of producing hydrogen from renewable energy the favourable process compared to the less efficeint  single step process.  This device will act as a selective membrane that removes hydrogen from almost any mixture of gasses at a very small cost in energy.  A large prototype is currently undergoing testing with H2-NRG Ltd.

Proton Pumping for Hydrogen Analysis

100_3253 Proton Pump

In the same way that a proton exchange membrane can be used to remove hydrogen from a mixture of gasses, the device can be used to move hydrogen from one chamber to another. In doing so, the current used to drive the device is proportional to the amount of hydrogen that has been transferred. it is therefore possible to build a device that measures hydrogen as a function of current. I am busy trying to build hydrogen measuring devices to allow the real-time following of chemical reactions that yield hydrogen.

Sulfur as the feedstock for future polymers

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Inverse vulcanisation allows us to make polymers out of sulfur.  Sulfur is a waste material form the oil and gas and steel industry and is therefore an attractive material to use as a raw material.  these beautiful red polymers can be made and functionalised with nanoparticles and liner chemistry to make high end plastics.

 

 

 Self-Cleaning Hard Surfaces for Hospitals

St pancrasThe ability to functionalise a surface so that it self cleans is a fundamental stepping stone in the concept of multiple functionality.   Self cleaning windows have been around for a while with examples such as the 18000 panes of glass in the roof of St. Pancras International Train Station.

Self cleaning glass works by absorbing UV light into a semi-conductor (TiO2) and using this energy to catalyse the decomposition of grease on the surface.

Grease + Sunlight → CO2 + H2O

The key is to modify the semiconductor photo-physics properties of the semiconductor to change the band gap and allow the material to absorb visible light.  In this instance you have a material that will self clean when indoors, with huge implications in the healthcare environment   in 2008 7500 people died as a result of hospital acquired infections such as MRSA and E. coli. Coating surfaces such as door handles,, bed frames loo flush handles with a functionalised self cleaning surface would help prevent the spread of these micro-organisms.

2 YouTube Videos

Self-Cleaning Soft Surfaces for Hospitals

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Soft materials such as polymers can be made to self clean using a similar photo-catalytic process however this time using a reox dye.  This has enabled the processing of items such as keyboard covers, and catheters to be functionalised. We use a swell encapsulation technique to facilitate the incorporation of redox dyes and nano-particles into the polymer structure and provide functional properties. 80% of all hospital acquired infections are resultant from catheter use, so having a catheter that is inherently antimicrobial is of prime interest.  Another common source of bacteria in hospitals is the keyboard covers used by the nurses at their ward stations.  These are commonly touched by numerous people and have the potential to aid the spread of bacteria and act as a reservoir for infection. As pictured,  I currently have 20 keyboard covers going through clinical trials at UCLH.  The Blue keyboard cover is blue because I have swell encapsulated the polymer with methylene blue and gold nano-particles. I-phone covers and water pipe can also be functionalised for self cleaning properties.