Effect of curing temperature of phthalonitrile resin on the properties of resultant hierarchical porous carbon

Abstract

Heteroatom-doped porous carbon materials have been widely studied due to their high specific surface area and high heteroatom content, but it is difficult to achieve high specific surface area and high heteroatom content at the same time. Herein, a simple method is introduced to prepare N/O co-doped hierarchical porous carbon materials (DNZKs). Phthalonitrile resins (DNZs) were prepared by using 1,3-bis(3,4-dicyanophenoxy)benzene as raw material and ZnCl₂/urea as composite curing agent, and then using KOH as activator to successfully prepare DNZKs with high specific surface area, developed pores and high N/O content. The porous carbon material (DNZK@400) obtained at a curing temperature of 400 °C has the highest N content (4.97% (mass)), a large specific surface area (2026 m²·g⁻¹), a high micropore proportion (0.9), a high O content (7.53% (mass)), and the best specific capacitance (up to 567 F·g⁻¹ at 0.1 A·g⁻¹), which can be attribute to the high temperature resistance of the nitrogen-containing aromatic heterocyclic structure in DNZs. When the mass ratio of resin and KOH is 1:1, the specific capacitance of the sample tested by the acid three-electrode system is obtained, and it is found that the material has high cycling stability (119% specific capacitance retention after 100,000 cycle tests). This work proposes a simple and easy-to-operate method for the preparation of multifunctional porous carbon.