Fe-Catalyzed CO Adsorption over Hexagonal Boron Nitride with the Presence of HO.

The energy barrier of CO chemically adsorbed on hexagonal boron nitride (h-BN) is relatively big. In order to cut down the energy barriers and facilitate fast adsorption of CO, it is necessary to apply catalysts as a promoter. In this study, single-atom iron is introduced as the catalyst to reduce the energy barriers of CO adsorbed on pure/doped h-BN. Through density functional theory calculations, catalytic reaction mechanisms, stability of single-atom iron fixed on adsorbents, CO adsorption characteristics, and features of thermodynamics/reaction dynamics during adsorption processes are fully investigated to explain the catalytic effects of single-atom iron on CO chemisorption. According to calculations, when CO and OH get into activated states (i.e., CO and OH) with the help of single-atom iron, their chemical activities will be promoted to a large degree, which makes the transition state (TS) energy barrier of HCO to decrease by 92.54%. In the meantime, it is proved that single-atom iron could be stably fixed on doped h-BN with the binding energy larger than 2 eV to achieve sustainable catalysis. With the presence of single-atom iron, TS energy barriers of CO adsorbed on h-BN with the presence of HO decreased by 94.39, 78.87, and 30.63% over pure h-BN, 3C-doped h-BN, and 3N-doped h-BN, respectively. In the meantime, thermodynamic analyses indicate that TS energy barriers are mainly determined by element doping and temperatures are a little beneficial to the reduction of TS energy barriers. With the above aspects combined, the results of this study could supply crucial information for massively and quickly capturing CO in real industries.