Fig. 4
From: Durable and self-hydrating tungsten carbide-based composite polymer electrolyte membrane fuel cells
Investigation of fresh and used Nafion membranes by FIB-SEM tomography. The white regions correspond to the catalyst (Pt or WC nanoparticles) embedded in the Nafion membrane, while voids within the Nafion membrane are depicted in red. a A representative region of PEM sample during FIB-SEM tomographic investigation. The focused ion beam removes a 12 nm-thick layer of the membrane during each pass, while an electron beam records its SEM image. b, c 3D reconstruction of fresh Pt/Nafion and WC/Nafion membranes, respectively. d–f 3D reconstruction of used Nafion, Pt/Nafion and WC/Nafion membranes, respectively, after 100 h of fuel cell operation
