It has been estimated that approximately 80% of all products have been in contact with a catalyst sometime during the manufacturing of the product. Catalysis science is fundamental to the production of the fuels, chemicals, and plastics that we rely on for our lifestyle, and provide the energy needed. Indeed, it has been suggested that the only reason that this planet Earth can support 7 billion people is due to a single catalytic process; ammonia synthesis. The discovery of the initial ammonia synthesis catalyst was a result of many years of research where many thousands of catalysts were tested. Today, the catalyst researcher has a very different toolset available to enable discovery and understanding on an unprecedented level through a combination of theory, synthesis, characterization and testing. All of these are needed if we are to understand the complex world of catalysis science, and discover new catalysts that will lead to a sustainable production of fuels and chemicals.
From the very early days of dedicated synchrotron light sources it was clear that the intense x-ray beams could be used to probe the structure of catalysts, primarily using x-ray spectroscopy. The modern era of extended x-ray absorption fine structure (EXAFS) began in 1971 with the pioneering paper by Sayers, Stern and Lytle, in which they elucidated the fundamental physics of the technique. It was only three years later that the first EXAFS paper mentioning its application to catalysis was published. Since that time the number of papers, and the subsequent impact on catalysis science, has grown dramatically as researchers have understood the critical structural and chemical information that can be determined on the working catalyst using X-ray Absorption Spectroscopy (XAS).
However, it has become clear that, despite the potential for XAS and other synchrotron techniques to provide this critical in-situ/operando structure determination of working catalysts, synchrotron techniques are underutilized by the catalysis community in the USA, and abroad, due in part to a variety of real and perceived barriers. At SSRL, we have a new initiative, funded by DOE-BES, the Consortium for Operando and Advanced Catalyst Characterization via Electronic Spectroscopy and Structure (Co-ACCESS). The aim of this program is to allow any catalysis science user group (studying heterogeneous, homogeneous or electro-catalysis) to readily apply the capabilities at SSRL into their research program, whether a one-time measurement or a component of a multifaceted research program.
Specifically, the goals of Co-ACCESS include:
- Provide all levels of assistance to catalysis scientists conducting synchrotron-characterization experiments, in the framework of collaboration, to maximize the success of their research.
- Develop a suite of in-situ/operando reactors to cover a wide range of catalytic chemistry: thermal heterogeneous catalysis (both gas and liquid phase), homogeneous catalysis, and electro-catalysis that are compatible with the various beam lines at SSRL.
- Develop advanced experimental methodologies, e.g. modulation-excitation spectroscopy to differentiate active and spectator species, and combined X-ray absorption/diffraction experiments.
- Develop a multi-modal spectroscopy platform, incorporating FTIR and Raman (and potentially UV-vis) spectroscopies.
- Improve beamtime scheduling to accommodate experiments that require prolonged run times (e.g. long-term deactivation studies).
- Offer guidance and support in all aspects of a synchrotron experiment – from proposal writing, to experimental planning, to data analysis and publication. This will lead to increased efficiency of operations.
- Offer educational opportunities to graduate students to learn advanced data modeling of XAFS data.
- Leverage the user-friendly "can do" attitude of SSRL to focus on demanding experiments that require expertise from diverse backgrounds, and patience.
The overarching goals of our group are to take existing powerful characterization tools at SSRL and to integrate them into capabilities that are accessible to any catalysis researcher, to develop and apply new, even more powerful methods that will lead to new understanding and breakthroughs.