UCL Chemistry

Our interest lies in the design of nanoporous framework materials for a variety of applications, including catalysis and gas separation. Using computational methods, we can compute the structures and properties of numerous hypothetical materials with desirable properties, and estimate how feasible they would be to synthesize. We explore fundamental links between chemistry and topology. A number of our predicted structures have subsequently been made. The materials include both zeolite types and metal-organic frameworks which are of interest for carbon dioxide and hydrogen storage. 

My research is centred on the use of Chemical Vapour Deposition (CVD) to deposit thin films of functional materials. 

The applications I have been targeting range from microelectronics to energy (active solar control coatings for energy demand reduction and catalysts for generation of hydrogen from water) through to the environment (gas sensing).

Principally my recent work has focussed on transparent conducting oxides, due to the unusual co-existence of optical transparancy AND electrical conductivity found in these materials, which is combined with chemical reactivity at the surface whilst the materials themselves are also relatively robust.

Recent research on the use of CVD for the deposition of composite thin films composed of bismuth oxide and platinum nanoparticles, which gain the property of being able to split water, evolving hydrogen, under photoillumination, a property not present in either of the constituents of the composite alone, has been featured in a“Young Investigators Award” issue of Inorganic Chimica Acta.

I am also currently interested in the opportunities afforded by CVD to synthesise materials with high purity and precise structural control at the nanometre scale level at the relatively low processing temperatures required for the fabrication of nanocrystalline materials. By altering the deposition conditions to control the chemical reaction it is possible to obtain nanocrystalline powders, nanostructured materials or thin films. Hence CVD is a technique with great promise for synthesis of functional nanomaterials.

Recent research is concerned with the use of AACVD for the synthesis of metal nanoparticle modified metal oxide nanostructures, with the aim of producing highly sensitive and highly selective gas sensors. This work, which is supported by theLeverhulme Trust, has recently been featured in an Emerging Investigators issue of Chemical Communications.

We are interested in developing innovative new routes to inorganic materials via chemical vapour deposition (CVD). The research involves the synthesis of molecular precursors to a range of materials including transition metal nitrides, selenides and Group III nitrides and oxides. The aim is to develop new highly volatile, non-toxic CVD precursors, which are then used to grown thin-films via low-pressure, and aerosol-assisted CVD.

• Materials Chemistry Centre

A powerful combination of computational and experimental techniques is used to explore a wide range of problems in current materials chemistry. Strong emphasis is given currently to (1) prediction of reaction mechanisms in heterogeneous catalysis, (2) prediction of crystal and nano-particle structures, and (3) elucidation of mechanisms of crystal growth and nucleation. We exploit the latest high performance computing technologies, which we combine with experimental studies using synchrotron radiation techniques.

Our work examines computationally the properties of crystalline solids; the main areas of research cover the functional behaviour of transition metal bearing compounds, and the synthesis and catalytic activity of doped nanoporous solids. We are also interested in applying computational methods to related areas, when unusual behaviour is observed experimentally that would benefit from the atomic-level insight enabled by modelling. From a methodological perspective, we address the performance of hybrid density functionals to study structural and electronic properties of solids. 

Research of Dr Darr's Clean Materials Technology Group (about 10 researchers at present) is concerned with the application of green principles and clean technologies for the rapid and efficient syntheses of nanoparticles or new inorganic materials. Our research is very applied and multidisciplinary covering chemistry, nanomaterials, high pressure engineering, supercritical fluids and automation. Dr Darr is currently leading two large EPSRC/industry funded consortia in nanomaterials discovery and scale-up engineering of nanomaterials, respectively.

• The Clean Materials Technology Group

Our work includes Polymer-clay Nanocomposites in which low levels of mineral addition increase mechanical and transport properties of polymers, Ordered, Biomimetic Mineral-polymer Composites in which layered minerals at high volume fraction emulate the structure of mollusc shells, Extrusion freeforming of EBG structures and hard tissue scaffolds and High Throughput experiments on ceramics. The image shows a robotic ink-jet printer for making thick film ceramic samples.

• UCL Centre for Materials Research

Our research focuses on multiscale syntheses and simulations of nanostructures and materials for energy/hydrogen generation, storage, energy catalysis, biofuel cells and biointerfaces. Fundamental theories are coupled with ab initio, molecular dynamics, cellular automata and finite element simulations for materials design and discovery, while selected materials are synthesised by mechanochemical alloying, self-assembly, deposition and precipitation methods. Materials systems cover clusters, metals, hydrides, oxides, metal-doped carbon nanostructures, and functional hybrid systems that show desirable properties for clean energy and biomedical applications.

• UCL Centre for Materials Research

Our work centres on molecular transition metal chemistry. Current projects include; the synthesis and study of diiron dithiolate complexes as biomimetic models for the iron-only hydrogenase enzyme, which is used in nature to convert protons to hydrogen, the use of well-defined gold clusters as precursors to gold nanoparticles for applications in heterogeneous catalysis, and the preparation of backbone functionalised dithiocarbamate complexes for applications in materials and biological processes. 

We develop and apply quantitative computational techniques to investigate at the atomic level structure/property relationships in a range of natural minerals and functional materials. Present research areas include 1) precious metal and transition-metal oxide surfaces for selective oxidation catalysis; 2) radiation damage in geological materials; 3) nucleation and growth of metal and metal-oxide nano-clusters; and 4) materials for bio-medical engineering.

• Applied Chemical Crystallography - Industrial Materials Group
• Materials Chemistry Centre

Our group explores solid state chemistry under extreme high pressure and high temperature conditions using large presses and laser heating techniques in the diamond anvil cell. New compounds and materials are prepared and studied at up to a million atmospheres and thousands of degrees centigrade using spectroscopy and synchrotron X-ray diffraction. We also study the properties and structure of liquids, amorphous solids and biological molecules at high pressure.

• UCL : Static High Pressure Group
• Centre for Materials Research

Our group is concerned with developing innovative routes to technologically important inorganic materials. We also have a strong interest in the preparation and characterisation of new materials especially aspects of composition and microstructure. The group is involved in research in Atmospheric Pressure Chemical Vapour Deposition (APCVD), solid state metathesis, self propagating high temperature synthesis, antimicrobial coatings (both hard surfaces and polymers), the formation of gold nanoparticle conjugates and combinatorial CVD. We have also developed projects in frustrated magnetism and metal oxychloride intercalation chemistry, amorphous alloys, chemical synthesis of nano-scaled materials and ELNES.

A recent research highlight on surfaces engineered to have different interactions with water can be viewed here.

The Tocher group collaborates in the area of X-ray crystallography across a wide range of chemistry, from conformational studies of flexible organic molecules to characterisation of new inorganic and organometallic compounds with potenital applications in catalysis and materials chemistry. Of particular interest is the study of polymorphism, work carried out in conjunction with computational chemists with a view to gaining an full understanding of the factors controlling the crystallization process.

• Control and Prediction of the Organic Solid State Project

We have been involved in designing catalytic reaction based on the structure determined from various characterisation techniques. Some of the recent examples include (a) the development of iron containing nanoporous aluminophosphate catalysts for the selective oxidation of benzene to phenol in presence of nitrous oxide and (b) supported nano gold clusters for the selective oxidation of hydrocarbon. Nanoporous materials. In addition to the above, we have been involved in developing in situ methods for following the crystallisation process of (a) nanoporouos materials, (b) multi-component mixed metal oxide catalysts and (c) nano materials. Majority of the characterisation is carried out using Synchrotron Radiation techniques

• Materials Chemistry Centre

We are interested in the synthesis and electronic structure of lanthanide complexes, particularly the bonding in cerium (IV) species. We are also involved in the low temperature templated synthesis of mesostructured materials of such semiconductors as titanium dioxide, silicon, and germanium.