The single metal atom (Ni, Pd, Pt) anchored on defective hexagonal boron nitride for oxidative desulfurization

Abstract

Single-atom catalysts (SACs) have attracted great attention for various chemical reactions because of their strong activity, high metal utilization ratio, and low cost. Here, by using the density functional theory (DFT) method, the stability of a single VIII-group metal atom (M = Ni, Pd, Pt) anchored on the defective hexagonal boron nitride (h-BN) sheet and its possible application in oxidative desulfurization (ODS) are investigated. Calculations show that the stability of the single M atom embedded in the h-BN surface with B and N vacancies is strikingly enhanced compared to that on the perfect h-BN surface. The catalytic activities of the defective h-BN-supported single metal atom are further studied by the activation of molecular oxygen and subsequent oxidation of dibenzothiophene (DBT). O₂ is activated to the super-oxo state with large interaction energies on three M/V_N surfaces. However, among the three M/V_B surfaces, only Pt/V_B performs efficient activation of O₂. The oxidation of DBT proceeds in two steps; the rate-determining step is the initial step, in which activated O₂ oxidizes DBT to produce sulfoxide. By comparing the energy barrier in the first reaction step, both Ni/V_N and Pt/V_B are revealed as promising candidates for the ODS reaction.