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

Abstract

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.