Anchoring the late first row transition metals with B12P12 nanocage to act as single atom catalysts toward oxygen evolution reaction (OER)

Abstract

The high over-potential associated with water splitting hinders the wide production of hydrogen and oxygen gases. Recent advancements in this field are being made by exploring novel, low-cost and highly efficient catalysts to lower the over-potential of the water splitting reaction. Herein, we studied the novel single atom catalysts (SACs) based on late first-row transition metal doped boron phosphide (B12P12) nano-cages for the electrocatalysis of the oxygen evolution reaction (OER) via density functional theory (DFT) calculations. The choice of using boron phosphide nano-cages as the support is based on the highly desirable properties within it. Namely, having many defects, excellent electrical conductivity, large surface area, and high chemical stability. The Ni@B12P12 and Co@B12P12 SACs exhibit high chemical stability, having interaction energies of −1.70 and −2.55 eV, respectively. Moreover, the results of quantum theory of atoms in molecules (QTAIM) analysis confirmed that the transition metals are covalently chemisorbed on the nano-cages, such strong interactions are desirable in SACs to ensure they withstand harsh chemical environments and are active for longer time period. Frontier molecular orbitals (FMOs) analysis indicates that the designed catalysts have semi-conducting capabilities which facilitate the transfer of electrons. The calculated FMOs energy gap (H-L Egap) values range from 2.01 to 2.88 eV. Results of OER activity analysis indicate that Ni@B12P12 and Co@B12P12 are promising OER SACs with low overpotentials (1.01 and 1.06 V, respectively). The result of this study highlights the viability of B12P12 nano-cages as supports in SACs and encourage the exploration of other nano-cages in the catalysis field.