Carbon adsorption on doped cementite surfaces for effective catalytic growth of diamond-like carbon: a first-principles study

We studied the adsorption of carbon on (100), (010) and (001) surfaces of alloyed cementite (Fe2MC with M = Cr, Mn, Mo, Ni and V), in comparison with that of cementite (Fe3C), to predict the catalytic effect of the element-doped cementite on diamond-like carbon (DLC) growth through first-principles analysis. The adsorption of carbon on the alloyed cementite surface is related to its surface stability. The more stable a surface, the weaker its adsorption capability. Mn, Mo, Cr or V alloyed cementite have a higher adsorption energy than unalloyed cementite. A correlation has also been found between the adsorption and the transferred charge based on Bader charge analysis. Among all the types of doped cementite under study, Fe2NiC possesses the strongest catalytic activity for DLC growth based on the formation energy of diamond carbon. Doping cementite with the appropriate elements provides a promising means to improve the catalytic activity of Fe3C for effective DLC growth.