Controlled formation of ball-milled carbon quantum dots via optimized graphite structures by numerical simulation

Optimized graphite structures enable high carbon quantum dot yield from ball-milled coals. Carbon quantum dots (CQDs) have been widely employed in various applications. The mechanical ball milling method for synthesizing CQDs from coal is considered as one promising approach towards scalable fabrication. However, the exact formation mechanism and the kinetic process of CQDs from ball milling remain ambiguous. Herein, a numerical model for simulating the formation of CQDs during the ball milling process has been successfully established. Two representative types of coals, anthracite and bituminous, were adopted as carbon sources, yielding 53.26% and 74.55% of CQDs, respectively. Moreover, we revealed that the intrinsic structure of graphite in coals including lateral length and vertical thickness could significantly impact the CQD formation. These findings provide essential guidance for further enhancing the yield of CQDs.