Materials science and renewable energy

The Fundamental Studies of 2D Materials group, led by Dr Balakrishnan, studies the electronic, optical and optoelectronic properties of 2D materials, especially the III-VI semiconducting layered materials. Among the large family of 2D materials, the III-VI (III = Ga, In, and VI = S, Se, Te) compounds are attracting increasing interest for their excellent electronic and optical properties. These materials exist in different stoichiometry and/or polytype phases (alpha, beta, gamma, etc.) with physical properties relevant for applications in electronics, thermoelectric and optoelectronics.

The main focus of this group is scalable production and to control the stoichiometry and phases of the III-VI layers. They are developing physical vapour deposition and chemical vapour deposition methods for the growth of III-VI layers. This group is also active in fabricating devices for optoelectronics, ferroelectrics, thermoelectric and twistronics.

For further information see Dr Balakrishnan’s homepage.

Thermo-acoustic engineering

 Broadly speaking, the research of Professor Maria Heckl's group is in physical acoustics with technical applications. More specifically, the focus is on the interaction of acoustic waves with

• flames (thermoacoustics)
• vortices and jets (aeroacoustics)
• structures (vibroacoustics)

Maria has been leading major European research consortia to understand such interactions in combustions systems (gas turbines, boilers, furnaces, aeroengines, rockets) and hence to underpin the development of clean combustion technologies, in particular hydrogen combustion.

Her most recent large-scale project, the H2020-funded ITN POLKA (POLlution Knowhow and Abatement), 2019 – 2023, has a total budget of €4.02 million, 16 network partners and 15 PhD positions. The aim of POLKA is to create new physical insights and advanced simulation tools to underpin the development of hydrogen-fuelled combustion systems. Details can be found on the project website www.polka-eu.org.  This research is linked to Keele's sustainable future agenda, and the SEND and HyDeploy projects in particular.

The forerunner of POLKA was the FP7-funded ITN TANGO (Thermoacoustic and Aeroacoustic Nonlinearities in Green combustors with Orifice structures), 2012 – 2016, which had a total budget of €3.74 million, 12 network partners, 14 PhD positions and one post-doctoral position. Details can be found on the TANGO website http://www.scm.keele.ac.uk/Tango/.

The group's expertise also includes vibroacoustics. In her research on railway noise, Maria established a model for the physical effects that are responsible for the squeal noise produced by the wheels of a cornering train. This research gave crucial input for the development of an effective squeal control method, which is now used in transport systems all over the world, such as the metros of Tokyo, Beijing and Madrid. In her research for the nuclear industry, Maria modelled the sound propagation of acoustic waves in a large-scale heat exchanger, comprising an array of many tubes immersed in liquid. This work supported the development of an acoustic detection technique (similar to computer tomography) to locate faults in the heat exchanger at an early stage.

For further information see the personal webpage of Professor Maria Heckl

Computer modelling research of materials, led by Dr Rob Jackson, involves application of atomistic modelling methods to mixed metal fluorides and oxides with potential applications in optical and energy devices. Use is made of the GULP code, and potentials are derived using empirical fitting, or taken from literature sources, including this useful resource from UCL. Lattice energy minimisation is used to predict structures, and Mott-Littleton methodology or supercells are used to model defects and dopants in the structures.

Mixed metal fluorides and oxides, when doped with rare earth metals, have applications as solid state lasers and sensors. Atomistic modelling is used to predict the location of dopants in the host lattice, and the energetically favoured form of charge compensation, if needed. This information can be useful if the doped material is to be synthesised. The figure below shows SrAl₂O₄: Eu³⁺, Dy³⁺ synthesised by laser melting, and the colour change that results from UV light exposure. A computer modelling study of SrAl₂O₄: Eu³⁺, Dy³⁺ can be found here.

External collaborators include Mário Valerio on modelling mixed metal fluorides and oxides (UFS, Brazil, megvalerio@academico.ufs.br), and Krisztian Lengyel (Wigner Research Centre, Budapest, Hungary, lengyel.krisztian@wigner.hu) on LiNbO3

The Computational Materials Physics group, led by Dr Juliana Morbec, is devoted to computational study and design of materials for technological applications. We use high-performance computer simulations based on state-of-the-art first-principles quantum mechanical methods to investigate the electronic, magnetic, optical and transport properties of different systems, from molecules to two-dimensional (2D) materials and surfaces. Our goal is to gain deep understanding of properties, processes and phenomena on atomic level in order to predict and design materials for spintronics, optoelectronics, sensors, catalysis, and energy conversion. We work in close collaboration with experimentalists joining efforts to explore novel materials and discover new properties. The group's current interests include (i) 2D materials and van der Waals heterostructures for flexible and portable applications, (ii) hybrid organic/inorganic materials for optoelectronic applications, (iii) transition metal oxide and nitride semiconductors for solar water splitting, and (iv) nanomaterials for spintronics.

For further information, see Dr Juliana Morbec’s website

The project aims to develop quantitative approaches to the characterisation of heterogeneous catalysts, such as bifunctional catalysts that contain both acid and metal sites. The research areas will include: (i) preparation of catalysts with controlled acid and metal functions and (ii) characterisation of these nanostructured materials using a range of analytical techniques. The project aims to generate new insight in structure - catalytic performance relationship and the role of active sites in catalytic reactions, hence providing a basis for the design of new heterogeneous catalysts with high activity, selectivity and stability. The projects would also be focused on the development of new approaches and methodologies for the characterisation of bifunctional catalysts. The project will give you an opportunity to achieve a professional level in the preparation and characterisation of nanostructured catalysts, their applications and industrial relevance.

For more information, please contact Dr Vladimir Zholobenko.

Renewable technologies are fast becoming a foundation of the modern energy infrastructure, with net zero energy systems emerging as viable options to replace fossil fuels. Our research uses electricity to sustainably generate fuels and chemicals from greenhouse gases and waste streams. Electrolysers, which are the devices used to enable these reactions, are composed of a cathode, where the reduction reaction takes place, and an anode which carries out an oxidation reaction. At the cathode, we generate hydrogen from water and carbon fuels from carbon dioxide. At the anode, we produce oxygen from water or valuable chemicals from waste materials such as biomass. The objective is to increase production with reduced costs by implementing novel catalysts and techniques for electrocatalytic conversions.

For more information, please visit www.creissenlab.com

Small-angle scattering is a powerful and versatile analysis tool that can selectively detect structures with dimensions ranging from 1 - 100 nm. This is the size region in which nanotechnology operates, and consequently, SAS is regularly used to investigate structures within a range of soft (molecular assemblies, gels) and hard materials (including catalysts, building materials). Current projects aim to synthesise, prepare and characterise (in part using SAS) soft organic materials including micelles, microemulsions, gels and liquid crystals with potential applications in imaging or in organic electronics.