Driving catalytic carbyne formation within endohedral DWCNTs: the role of Ni <i>vs.</i> Pt

The growing demand for high-modulus, high-strength, and lightweight materials has spurred interest in carbynes; however, their catalytic synthesis mechanisms remain largely unexplored. In this study, we use reactive molecular dynamics simulations to investigate the catalytic synthesis of endohedral carbynes within double-walled carbon nanotubes, comparing the distinct roles of Ni and Pt catalysts. Our findings indicate that Ni catalysts are more effective, promoting a stable, self-propagating chain growth mechanism with the potential for extreme lengths. In contrast, Pt catalysts exhibit higher energy barriers, resulting in fragmented, metallic carbyne-like structures; a finding which provides a mechanistic explanation for experimentally observed metalated carbynes. This study not only identifies an efficient catalyst for carbyne synthesis but also suggests a new route to novel encapsulated materials, advancing the rational design of nanocarbons for demanding applications.