Institut de Physique et Chimie des Materiaux de Strasbourg (IPCMS) 1 article published in JoVE Chemistry Obtaining 3D Chemical Maps by Energy Filtered Transmission Electron Microscopy Tomography Lucian Roiban1, Loïc Sorbier2, Charles Hirlimann3, Ovidiu Ersen3 1Univ Lyon, INSA-Lyon, Université Claude Bernard Lyon 1, 2IFP Energies nouvelles, 3Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS) This paper describes a protocol to achieve 3D chemical maps combining energy filtered imaging and electron tomography. The chemical distribution of two catalyst supports formed by elements that are difficult to distinguish by other imaging techniques was studied. Each application consists of mapping overlapped chemical elements - respectively spaced-ionization edges.