In recent work we have identified a very powerful and extensive phenomenon, the constrained production of nanoparticles that opens up a new field impinging on chemistry, materials science and physics. The dispersion, stability, versatility and coherence with the substrate impart quite significant properties to the emergent nanoparticles opening up a major new topic. The process is driven by the lattice decomposition of a metal oxide under reduction by various means. Conventional thinking considers this as a simple phase separation; however, by careful control of the defect chemistry and reduction conditions, a very different process can be achieved. These nanoparticles emerge from the substrate in a constrained manner reminiscent of fungi emerging from the earth. The emergent nanoparticles are generally dispersed evenly with a very tight distribution often separated by less than one particle diameter.

Here we will explore the composition and reaction space conditions necessary to optimise functionality, structure and applocability. We will also seek to better understand this phenomenology relating to correlated diffusion, driving energetics and mechanism of emergence. Further work is necessary to understand the critical dependence of composition in a very extensive domain of composition space depending upon charge and size of the A-site cations, oxygen stoichiometry and transition metal redox chemistry. Of particular importance is to understand the nature of the interaction between the nanoparticle and the substrate addressing the evolution of the nanoparticles from the surface and how the particles become anchored to the substrate. Exolved metals can react to form compounds whilst maintaining the integrity of the nanostructural array and this offers much potential for further elaboration of the concept.

We will investigate the important catalytic, electrocatalytic and magnetic physics properties arising at constrained emergent particles, driven by dimensional restriction. Emergent nanomaterials provide very significant surface-particle interactions and promise new dimensions in catalysis. The electrochemical reactions in devices such as batteries and fuel cells are restricted to the domain very close to the electrolyte electrode interface. Emergent materials can be applied in exactly this zone.

Potential Impact:
We are proposing to develop our understanding and ability to control Emergent Nanomaterials, a new class of materials that due to their constrained nature and specific dimensionality offer remarkable new functionalities and capabilities. This could offer step-change new technologies and applications.
The work will be of considerable interests to chemists, physicists and materials scientists interested in structure property relations and the fundamental science determining functional properties. The area will also be of great interest to engineers looking to develop new devices, for energy storage and conversion, information storage, catalytic conversion and optoelectronics. There are also interesting synergies with biological structures and geochemical transformations.
The possible technological implications are very significant and there is already considerable excitement in the catalytic and energy conversion arenas. Companies such as Johnson Matthey, AFC Energy, Ceres Power and Rolls Royce are already interested and engaged. These new structures offer considerably improved stability and functionality and there is already a clear home for emergent nanomaterials in these arenas. Likely examples are exhaust catalysts, bioenergy reforming, low and high temperature fuel cell/electrolyser electrodes, plasmonic solar cell, lithium batteries and sensors. As we learn more we see opportunities to greatly reduce cost over existing systems and there are clear possibilities to greatly reduce precious metal requirements or even remove the need altogether. This addresses the strategic availability of the so-called critical elements.
We also expect to find important new physical phenomena as we know how much strain and constrained dimensions impacts upon such properties. This in turn may yield important new technologies that we can see commercialised in the UK.
There are important prospects to benefit society, not only do we see exciting technological advances, but also we see great prospects to improve energy security, energy efficiency and energy storage in environmentally friendly processes. In other words, appropriate introduction of new materials concepts such as these will greatly reduce CO2 production and can even assist in CO2 removal through utilisation. Undoubtedly these new technology advances, in energy and beyond, offer secured employment and new jobs. In turn this provides taxes and reduces cost for government to mediate climate change and hence benefits society and government.
Last but not least, this project will help shape the training and vision of the next generation of researchers by placing them in a truly multidisciplinary programme which will encourage fertile scientific thinking across techniques and disciplines, while providing clear scope of high-level scientific and national strategic targets.