2D RhTe Monolayer: A highly efficient electrocatalyst for oxygen reduction reaction.

Oxygen reduction reaction (ORR) electrocatalysts with excellent activity and high selectivity toward the efficient four-electron (4e) pathway are very important for the wide application of fuel cells and are worth searching vigorously. In this study, r-RhTe monolayer is identified as a good ORR electrocatalyst from three 2D RhTe configurations with low Rh-loading (i.e., r-RhTe, o-RhTe and h-RhTe) on the basis of the first-principles calculations. For the most energetically stable r-RhTe, two adjacent positively charged Te atoms on the material surface can provide an active site for oxygen dissociation. Coupled with its high stability and intrinsic conductivity, 2D r-RhTe monolayer is confirmed to possess good catalytic activity and high reaction selectivity toward ORR. Moreover, under the ligand effect caused by the substitution of Cr, Mn and Fe, the ORR catalytic activity of r-RhTe monolayer could be effectively enhanced, where very small over-potential was achieved, and even comparable to or lower than the state-of-the-art Pt (111). This shows it has considerably high ORR activity. This work is highly anticipated to provide excellent candidate materials for ORR catalysis, and the related researches based on the Rh-Te materials will provide a new way to design high-performance ORR electrocatalysts to substitute the precious metal Pt-based catalysts.