Single Si atom supported on defective boron nitride nanosheet as a promising metal-free catalyst for N2O reduction by CO or SO2 molecule: A computational study

The low-temperature reduction of N2O plays a significant role for solving the growing environmental and health issues caused by emission of this greenhouse gas. The aim of this study is to investigate the possible reaction pathways for the reduction of N2O by CO or SO2 molecule over Si-doped boron nitride nanosheet (Si-BNNS). According to our results, a B or N-vacancy defect in BN sheet could be able to greatly stabilize the single Si adatom. The relatively large diffusion barrier for the Si atom over the defective BN sheet also indicates Si-BNNS is stable enough to be utilized in catalytic reduction of N2O. The large charge-transfer from the surface to N2O leads to the spontaneous dissociation of this molecule into N-2 molecule and an activated oxygen atom (O-ads). The O-ads moiety is then eliminated by CO or SO2 molecule. The calculated activation energies and reaction energies reveal that the Si atom located on top of the B-vacancy site has a large catalytic activity toward the reduction of N2O by CO or SO2.