Exploring Stability of Transition-Metal Single Atoms on Cu2O Surfaces

Single-atom catalysts (SACs) and single-cluster catalysts (SCCs) have aroused significant interest in heterogeneous catalysis. Transition metal (TM) atoms doped on metal-oxide surfaces provide an opportunity for tuning their electronic, magnetic, and catalytic properties. Herein, the structural, energetic, electrochemical, electronic, and magnetic properties of TMs doped at copper and oxygen vacancies on Cu2O surfaces are systemically studied using density functional theory calculation with dispersion correction. Among the 174 systems studied, we found 60 new stable potential SACs and SCCs. It is found that SACs prefer to form on the Cu2O(111) surface by replacing the second-layer coordination-saturated copper atom, while SCCs prefer to form on the Cu2O(110) surface by replacing the second-layer oxygen atom. Binding and formation energies of SACs and SCCs along d-series TMs show a shape of two peaks, which is caused by respective majority- and minority-spin electron occupancy of d orbitals, and formation of SACs is much more favorable than formation of SCCs on three low-index Cu2O surfaces. The charge transfer decreases along the d-series from left to right across the periodic table due to the orbital energy decrease, while the spin states of TMs for SACs and SCCs on Cu2O surfaces show periodic variation trends along d-series. Our results provide fundamental knowledge of TMs doped on Cu2O surfaces, which helps design new atomically precise heterogeneous catalysts via SACs and SCCs.