Effects of Framework Structures of Zeolite-Templated Carbons on Their Thermal Structural Transformations

Zeolite-templated carbons (ZTCs) are ordered microporous carbons synthesized by replicating the microporous structure of zeolites with carbon. Due to carbon growth within the confined spaces of zeolite micropores, ZTCs are composed of interconnected, buckybowl-like carbon moieties with abundant edge sites terminated by hydrogen (H) atoms. The amount of H-terminated edge sites and the local framework structure of ZTCs depend on their synthesis conditions. In this study, we investigated the effects of the initial framework structures of ZTCs on their thermal structural transformations. Our results demonstrate that ZTC frameworks primarily built with nanoribbon-like carbon moieties containing abundant H-terminated edge sites undergo significant dehydrogenation (removal of H₂) and concomitant formation of new C–C bonds upon thermal treatment, leading to increased carbon surface curvature, reduced micropore diameter and volume, and enhanced ultramicroporosity. These structural changes also lead to substantial modifications in macroscopic properties, such as oxidative stability, work function, and ppb-level chloroform adsorption capability in water. The findings highlight the unique potential of synthesizing microporous carbons with tailored structures and physicochemical properties through post-synthesis thermal transformation of ZTCs.