Our research interests are mainly on both
fundamental and applied aspects in Solid State Chemistry and
Heterogeneous Catalysis. Research work involves synthesis,
testing and characterisation of novel solid state materials for a wide
range of applications. The highlights below are some of the current
projects taking place in our group, which should give you an overview of
our research directions.
Currently, Prof. Tsang is
working on a number of projects concerning some alternative clean
technologies including "hydrogen production from
biomasses" and Johnson Matthey funded projects on fuel cell catalysts. Some of his very
recent research interests are in the areas of carbon dioxide activation,
capture, storage and subsequent conversion into useful chemicals/materials
(reduction in carbon loading in atmosphere)
and the development of alternative renewable
energy sources (carbon neutral catalytic processes) in
collaboration with a number of UK universities through UK EPSRC funded
consortia (Formic acid economy and C-cycle: CO2
capture, activation and utilisation) and industrial companies
(Johnson Matthey,
Thomas Swan and Aramco, etc) in order to take the long
term vision of reducing the carbon emission to the atmosphere.
Recent developments in nano-science have
opened up new directions in chemistry to allow the synthesis of novel nano-materials
which could not be obtained by conventional means. Current research
shows that they exhibit many fascinating size dependent properties. The use
of well-defined, well-characterised pre-formed nanomaterials as building
blocks for the synthesis of functional materials is a new direction for many
exciting applications.
We are developing novel core-shell
nanoparticles of controllable composition, size and morphology (see diagrams
below). Some of them show exceptional catalytic activity and selectivity
towards desired products. A new class of silica coated nano-magnet of
controlled dimensions to host biocatalysts with the unique advantage of
facilitating separation is also described by our group. By using simple nano-chemistry
skills, we show that Pt nanocrystals with tailored sizes can be decorated
with Co atoms in a controlled manner. The blockage of unselective Pt corner
sites by Co and its electronic influence to the Pt surface can dramatically
improve the catalytic performance of Pt for the selective hydrogenation of
α,β-unsaturated aldehydes.
In nano-sensor and biomedical areas, our
interests include using hollow carbon nanotube as nano-scale test tube for
catalysis, separation, storage, magnetic, electronic applications. Research
on attachment, testing and characterisation of enzymes and DNA in opened
carbon nanotubes at Oxford are underway. These studies open up
promising lines allowing developments of biosensors or drug or
gene-delivery/storage methods as well as nano-surgical devices. Also, we
are working on new synthesis of materials (magnetic, radionuclides)
encapsulated in nano-carbon onions. By teaming up with Manchester hospital
important applications of these encapsulated radioisotopes in
onions for medical diagnosis are being developed.
Heterogeneous catalysis plays a vital role
in energy provision and environment, which relates to both wealth and
welfare of mankind. Particularly, carbon dioxide (CO2) issue has
recently become the focus of global attention because of the position of CO2
as the primary greenhouse gas and the implication of its emissions on the
problem of climate change. Burning non-renewable fuels releases the CO2
stored millions of years ago. Deforestation decelerates the CO2↔O2
renewal cycle in the atmosphere.
Thus, we work in the areas of carbon
dioxide activation, capture, storage and subsequent conversion into useful
chemicals/materials (reduction in carbon loading in atmosphere) and the
development of alternative renewable energy sources (carbon neutral
catalytic processes) in collaboration with a number of UK universities
through EPSRC funded consortia (Formic acid economy and C-cycle: CO2
capture ,activation and utilisation) and industrial companies (Johnson
Matthey, Thomas Swan and Aramco, etc) in order to take the long term vision
of reducing the carbon emission to the atmosphere. Current projects
concerning hydrogen storage, development of fuel cell catalysts, cleaner
catalytic combustion, green chemistry (oil, gas and coal utilisation),
energy efficiency chemical processes (on-board reforming), catalytic
processes for energy productions (i.e. photocatalysis, reforming of
bio-fuels) are ongoing.
Today tremendous pressure is currently
exerted on chemical manufacturing industry to develop new synthetic
methods that are environmentally more acceptable. For example, oxidation
is an important industrial reaction but the current industrial practice is
to use stoichiometric oxidants (manganates, chromates, etc) that generate
a large quantity of inorganic pollutants. Our research is to seek cleaner
alternative catalytic oxidation processes. We are working on a number of
new approaches including the use of supported aqueous phase catalyst (SAPC)
which concerns the creation of a thin water film carrying a homogeneous
oxidation catalyst on a high surface area solid support in bulk organic
solvent. SAPC substantially increase the interfacial surface area and
provide an elegant way of heterogenising biphasic catalysts. Their main
advantages concern easy catalyst recovery and increased activity.
Selective oxidation of alcohols in supercritical carbon dioxide
supercritical fluids (SCFs) is also under our intense investigation. We
have recently shown that aerobic oxidation of alcohols to carbonyl
compounds in scCO2 is an attractive, environmentally friendly
alternative to the well-known aqueous phase oxidation on supported
platinum metal catalysts. Mechanistic elucidation indicates that the
favourable oxidative dehydrogenation of alcohol combined with readily
desorption of lesser hydrophilic intermediates i.e. aldehyde prevent the
alcohol from over-oxidation to acids with no detectable catalyst
deactivation and no metal leaching (see Scheme 1) in supercritical fluid
phase. Modify the hydrophobicity / hydrophilicity of the catalyst relative
to the CO2 can also lead to significantly increase in
conversion and catalyst stability.
Similarly, inorganic hydrides are
conventionally employed for a wide range of important organic syntheses
and many of them have proved to be excellent stoichiometric hydrogenation
reagents. However, the preparation and regeneration of the highly toxic
hydrides give separation and waste issues and so they are deemed
unsuitable for the pharmaceutical and cosmetic industries in modern
plants. Our approach is to carry out fundamental research to underpin the
development of new but cleaner heterogeneous hydrogenation catalysts for
their replacement.
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