Fabrication of high-strength macroporous carbons with tunable pore size by a simple powder process using phenolic resin microspheres

Abstract

High-strength macroporous carbons with tunable pore sizes were fabricated by the simple mixing–pressing–hardening–carbonization of phenolic resin microspheres as a matrix with acid-catalyzed furfuryl alcohol as a binder. Pore-size tuning with the open cell structures was possible by changing the diameters of the phenolic microspheres in the range of 8–100 μm. After pressing the mixture of phenolic resin microspheres and binder, hardening at 170 °C for 5 h in air, and carbonizing at 1000 °C for 1 h in nitrogen flow, the macroporous carbon was formed. The mean pore sizes of the macroporous carbons were 1.8, 6.6, and 27.5 μm for 8-, 25-, and 100-μm-diameter phenolic microspheres, respectively, and the corresponding bulk densities were 1.01, 1.00, and 0.94 g/cm3. The compressive strengths of the fabricated macroporous carbon samples were 106.8, 83.5, and 43.6 MPa for the 8-, 25-, and 100-μm-diameter phenolic microspheres, respectively, which were notably higher than those of typical carbon foams. The simple fabrication process with easily tunable pore size, which yields macroporous carbons with remarkably high mechanical strength, has potential for large-scale production and many applications.