Visualizing reacting single atoms in chemical reactions: Advancing the frontiers of materials research

Heterogeneous gas–solid catalyst reactions occur at the atomic level, and understanding and controlling complex catalytic reactions at this level is crucial for the development of improved processes and materials. There are postulations that single atoms and very small clusters can act as primary active sites in chemical reactions. Early applications of our novel aberration-corrected (AC) environmental (scanning) transmission electron microscope (E(S)TEM) with single-atom resolution are described. This instrument combines, for the first time, controlled operating temperatures and a continuous gas environment around the sample with full AC STEM capabilities for real-time in situ analysis and visualization of single atoms and clusters in nanoparticle catalysis. ESTEM imaging and analysis in controlled gas and temperature environments can provide unique insights into catalytic reaction pathways that may involve metastable intermediate states. Benefits include new knowledge and more environmentally friendly technological processes for health care and renewable energy as well as improved or replacement mainstream technologies in the chemical and energy industries.