Scanning Tunneling Microscopy (STM) is a powerful tool that leverages tunneling current to study the surface properties of materials at the atomic level. STM involves a sharp metallic tip brought very close to the surface of a material. When a voltage is applied, electrons tunnel between the tip and the surface, creating a measurable current. This current is highly sensitive to the distance between the tip and the surface, allowing for high-resolution imaging of surface topography and electronic states. STM has been instrumental in studying the active sites on catalysts, where reactions occur, and in observing changes in catalyst surfaces during reactions.
