a Three types of red fired bricks are utilized for synthesis. All types show homogeneous red-orange color under the optical microscope, indicating uniform α-Fe2O3 distribution. White spots on bricks (left top inset) show the gravel (SiO2) sizes increasing from type 1 to type 3 brick. Scanning electron micrographs exhibit different porosity for these three types of bricks with pore sizes decreasing from type 1 to type 3. b After synthesis, all types of bricks are homogeneously coated by PEDOT nanofibers of similar aspect ratio. c Powder X-ray diffraction pattern for type 1 brick shows a composition comprised of SiO2, α-Fe2O3, and Al2O3. d Type 2 and type 3 bricks show similar patterns and crystalline components. The sharper and stronger peak at 2θ = 28° from type 2 brick is due to its higher Al2O3 content or crystallinity. e Synthesis is scalable to decimeter-sized bricks.