Simple synthesis of nitrogen-doped zeolite-templated carbon and its use in electric double-layer capacitors

Abstract

Nitrogen-doped zeolite-templated carbon (N-doped ZTC) is synthesized using NaY zeolite as a template and with acrylonitrile (AN) and propylene as the respective nitrogen and carbon sources. AN is directly mixed with the dried zeolite for adsorption and the mixture is heated to synthesize polyacrylonitrile (PAN) inside the zeolite micropores. Each AN adsorption and polymerization step require only 1 h and both steps were performed in a single container. The resulting zeolite/PAN composite was then subjected to chemical vapor deposition using propylene to fill the zeolite pores with carbon. Subsequently, heat treatment was used for carbonization and the zeolite was removed with hydrofluoric acid. The N-doped ZTC has three-dimensionally ordered and interconnected micropores with a uniform pore size of 1.2 nm, inheriting the structural regularity of the zeolite. The optimum volume of AN is determined to be the same as the total pore volume of the zeolite, which accounts for the high surface area of 3680 m² g⁻¹ and high structural regularity with a N/C molar ratio of 0.015. The performance of the N-doped ZTC as an electric double-layer capacitor electrode was evaluated using an organic electrolyte and showed a superior performance to undoped ZTC and maintained a high capacitance retention up to 2 A g⁻¹.