Formation and scaffold interaction of zeolite-templated carbons – Insight from solid-state nuclear magnetic resonance spectroscopy

Zeolite-templated carbons (ZTCs) combine unparalleled textural properties and high electric conductivity, making them promising candidates in energy applications, such as electrodes in batteries and in fuel cells or as catalyst supports. However, rather little is known about the formation mechanism of the carbon phase within the zeolite, its molecular interactions with the template zeolite and about the structure of the final carbon materials on a molecular level. Herein, we systematically examine the formation mechanism of ¹³C-enriched ZTCs synthesized using two zeolites with FAU and EMT topologies by solid-state NMR spectroscopy. By variation of the synthesis time we observe intermediate stages of the carbon formation, suggesting that individual zeolite voids are initially filled with smaller carbon species that progressively grow into larger structures. Direct interaction between the protons of the zeolitic host and the nascent carbonaceous phase could not be evidenced. However, a closer examination of the zeolitic scaffolds revealed that the short-range structure of the zeolite is impacted during carbon formation, with distortions in bond angles and lengths induced by the guest phase.