Advancements in in-situ transmission electron microscopy for comprehensive analysis of heterogeneous catalysis: insights into the nanoscale dynamic processes

The advances in transmission electron microscopy (TEM) have greatly improved the characterization of heterogeneous catalysts, offering valuable insights into their operational efficacy through the correlation of their physico-chemical characteristics with performance, specificity, and robustness at nanoscales. Understanding tangible catalyst attributes and corresponding catalytic processes necessitates the identification and rationalization of catalyst behavior modifications during reaction conditions. Recent innovations in in-situ TEM techniques have opened new avenues to observe the progress of heterogeneous catalysis with unparalleled spatial precision, superior energy resolution, and precise temporal resolution in controlled or realistic catalytic environments. Herein, we have reviewed the established and evolving techniques for monitoring catalysts through the utilization of in-situ TEM. By combining in-situ TEM with cutting-edge spectroscopic methodologies like atomic electron tomography (AET), 4D-STEM, cryogenic electron microscopy, and monochromated electron energy loss spectroscopy (EELS), a comprehensive approach to catalyst observation is achieved. Likewise, this advancement is expected to highlight and expand the crucial role of in-situ TEM in elucidating catalyst surface structures, active sites, and reaction pathways across key catalytic reactions, shaping the field of research in heterogeneous catalysis. Finally, the potential applications, advantages, and challenges of using in-situ TEM are emphasized and addressed in detail.