The following link has the additional supplementary images missing from your link https://www.researchsquare.com/article/rs-112257/v1 https://www.researchsquare

The following link has the additional supplementary images missing from your link https://www.researchsquare.com/article/rs-112257/v1 https://www.researchsquare.com/article/rs-112257/v1 I quickly skimmed it but the protocol on page 13 seems simple, the chemicals involved are relatively low risk (verify the MSDS). Mix some gallium metal with a powder of a Silver salt in a mortar and pestle, put it in a solvent, stir it with a magnetic stirrer, while bubbling CO2, in a N2 atmosphere, and carbon snowflakes should float to the top in a few hours. Maybe some chemist can help make it into a safe for all kid science-fair project.