Development and Applications of Aberration Corrected Environmental STEM (AC ESTEM) for Dynamic In-Situ Reaction Studies of Nanoparticle Catalysts

We propose to create in the UK a novel research capability providing Angstrom Analysis for dynamic in-situ reaction studies under controlled conditions of temperature and continuous gas atmosphere rather than the usual high vacuum. The new design provides the world's first full function aberration corrected environmental scanning transmission electron microscope (AC ESTEM). In association with partners in the vibrant UK chemical and energy industries we will generate fundamental application science underpinning nanoparticle based solid state heterogeneous catalysis used in gas-solid reactions. We will modify an existing AC TEM/STEM instrument to complement and extend with gas reaction studies the National AC STEM Facility's superior image and energy resolutions in high vacuum. It will be used in York programmes and collaborative projects with other groups through the AC STEM. It builds on the PIs' established reputations for global leadership in ETEM, with most of the worldwide activity to date - all overseas - based on >10 high resolution ETEMs and many of them AC (on the TEM image side only), using core technology from the authors' earlier developments. Preliminary 'proof-of-principle' has been demonstrated on the remotely controlled double aberration corrected JEOL 2200FS TEM/STEM at York; combining sub-Angstrom (<0.1nm) resolution, unrestricted HAADF Z-contrast STEM imaging, wide angle electron diffraction and EDX (+ EELS) chemical analysis not available on ETEMs. The double aberration correction collects, in a single and often directly interpretable TEM image, a full range of spatial frequencies at close to zero defocus to minimise image delocalisation at internal interfaces such as grain boundaries, external surfaces, defects and other key discontinuities. This is especially important for dynamic in-situ studies with continuously changing data making impractical older through-focal series reconstruction methods. AC also transforms the sensitivity of STEM analysis. The work will use analytical methods established with 'frozen' and process extracted samples, and apply them to the study of continuous processes at new levels of sensitivity and relevance. Access to key intermediate states and phases may be critical to understand and control process mechanisms; but they may be metastable with respect to conditions, including temperature or chemical environment, and therefore not accessible through ex-situ or pulse studies. A very practical example, in which there is leading UK industry interest and support, is the nano-structure and related property stability of supported metal nanoparticle heterogeneous catalysts. Through synthesis, activation, operation, deactivation, reactivation and recovery mechanisms, understanding at a fundamental level is critical for managing on a rational basis industrial practice for sustained activity and selectivity; and where necessary recovering these key attributes when lost. The project direction is closely aligned with the domain science needs of real world academic and industrial applications, and there are early adoption prospects for underpinning key technologies; including to extend useful process life cycles. For example, this is critical for the wider commercial viability of fuel cells. The proposal has the support of leading UK companies in the vibrant and internationally competitive chemical industry sector, and of academic collaborators. At the same time, the new learnings in basic domain science are also directed towards opening up new applications of pressing societal value in the environment. Fundamental physical science research with strategic and tactical industrial applications leads to differentiated intellectual products with an initiative unique in the UK and fully competitive globally. The project will extend and apply core nanoparticle catalysis science and technology, and train a new cohort of students, postdocs, senior staff and visitors.

The project introduces to the UK AC ETEM and to the World full function AC ESTEM, in combination as AC (E(S)TEM), with a continuous controlled gas environment around the specimen for dynamic in-situ reaction studies of heterogeneous nanoparticle catalysts and related materials. AC ESTEM will have 0.1nm resolution HAADF Z-contrast imaging with single atom sensitivity, EDX chemical analysis and wide angle electron diffraction with CBDP. This will complement and extend application specific technical capabilities of the established EPSRC National Facility for high performance AC STEM and will be co-ordinated with that programme. We will work with partners in UK academia to provide wider access in the UK to the innovative new capability. Our project is focused on new methods of fundamental science applied to important heterogeneous catalyst technology applications in collaboration with leading British companies, whose expertise, interests and needs are contributing significantly to the planning, implementation, development and exploitation of the project initiative. The original partners, providing CASE studentships, are the catalyst businesses of Johnson Matthey and BP. Discussions with Shell are at an earlier stage. All three companies have staff involved with the laboratory work, the provision of materials synthesised for specific designs of experiment, access to other characterisation methods and broad catalyst performance characterisation. This means we can leverage resources and expertise without the need to establish them ourselves, and more effectively expose our students and staff to well established practices. The impact for each company will include (a) direct and specific tactical support for technology developments, (b) targeted background domain science, in some cases pre-competitive, to inform longer term strategic decisions, and (c) reputational association with the project, (d) results from it and where appropriate to refer problems to it. There is scope for new and more effective solutions to long standing problems in the chemical industry, new energy initiatives, in the environment and in remediation. The whole of Society (the people, companies and Government) stands to benefit above and beyond immediate operational profit in terms of lower cost and more efficient energy systems, cleaner emissions, more efficient, lower cost and more complete chemical reaction processes, with less waste products, and generally more stable and benign operations. The project needs to engage with all stakeholders to define and to implement beneficial solutions to underlying problems. Everyone benefits from new products and better chemical production processes with reduced waste and energy requirements. We propose to hold focus groups and targeted meetings to promote the agenda and generally to extend the benefits of the research. We will engage with wider activities of outreach. A major activity for which some funding support is requested, is to engage with the world wide scientific community by attending international conferences, especially in Europe, the US and Asia. We are organising sections of the next European Microscopy Congress, to be held in Manchester in Sept 2012, and if we are successful with funding this will be a suitable occasion for a very public launch of the project. We have established with each company pathways for interactions at the tactical, laboratory scale, and strategically at more senior corporate levels; informed by our own experiences at senior technical levels on major projects in (US) industry (see cvs). The most immediate impacts will be directly with the sponsoring organisations to inform decisions about current practices and future technology developments. This will be achieved by close contact in meetings, and in joint laboratory work, with senior management and technical staff from each company separately; and together at the pre-competitive stage.