Dimensionality Effect of Nanocarbon Precursors on Diamond Synthesis under Extreme Conditions.

Diamond holds significant promise for a wide range of applications due to its exceptional physicochemical properties. Investigating the controlled diamond preparation from nanocarbon precursors with varying dimensionalities is crucial to optimize the transition conditions and even elucidate the daunting transformation mechanism, however, this remains outstanding challenge despite considerable effort. Herein, the imperative dimensionality effect of nanocarbon precursors on diamond synthesis and the physical mechanism under high temperature and high pressure is reported, by comparing the distinct transition processes of 0D carbon nanocages (CNCs) and 1D carbon nanotubes (CNTs) from conventional graphite. The optical and structural characterizations evidently demonstrate that both 0D CNCs and 1D CNTs first undergo collapse and graphitization, followed by the formation of mixed amorphous carbon with embedded diamond clusters, eventually leading to cubic diamond. The plotted pressure-temperature diagram exhibits the unique dimensionality effect of carbon nanomaterials to diamond transformation. These results provide valuable insights into the phase transition mechanisms of diamond synthesis and its derivatives under extreme conditions.