The structural, electronic and magnetic properties of the (FeC)n (n = 1–8) clusters are studied using the unbiased CALYPSO structure search method and density functional theory. A combination of the PBE functional and 6–311 + G* basis set is used for determining global minima on potential energy surfaces of (FeC)n clusters. Relatively stabilities are analyzed via computing their binding energies, second order difference and HOMO-LUMO gaps. In addition, the origin of magnetic properties, spin density and density of states are discussed in detail, respectively. At last, based on the same computational method, the structures, magnetic properties and density of states are systemically investigated for the 3d (V, Cr, Mn and Co) atom doped (FeC)8 cluster.

Research into suitable substrate-supported single-atom catalysts has become a major challenge for electrochemical sensors and energy devices. Firstly, we investigate the adsorption properties of metal atoms (MA = Fe, Co, Ni, Cu and Al) on pristine and defective BC3 sheets through using first-principles calculations. It is found that the MA-doped BC3 configurations (MA-BC3) are quite stable at high temperature and the positively charged MAs as surface active sites can effectively regulate the stability of reactive gases. Secondly, the adsorption of individual O2 molecules is more stable than that of CO molecules, which can modify the electronic and magnetic properties of MA-BC3 systems. Moreover, the possible reaction processes of CO oxidation on the Fe-BC3 substrate are comparably analyzed through the Eley-Rideal (ER) and Langmuir-Hinshelwood (LH) mechanisms. In the LH mechanism, the coadsorbed O2 and CO as starting materials start to form an OOCO complex with a smaller energy barrier (0.38 eV), which is an energetically more favorable process than that of the OOCO (0.65 eV) or CO3 complex (0.42 eV) formed through ER mechanisms. This result indicates that the functionalized MA-BC3 sheets have low cost and high activity.

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