The correlation of NO chemisorption adsorption with its directly catalytic dissociation pathway on β-MnO2(110) and (101) surfaces

MnO2-based oxide catalysts have recently drawn so much attention owing to its good catalytic activity for NOx direct catalytic decomposition at low-temperature. As the reaction mechanism of NO direct catalytic decomposition on different MnO2 surfaces is not yet clear, it is important to understand the influence of different crystal surfaces of beta-MnO2 on catalytic activity for NO decomposition. The correlation of NO chemisorption with its dissociation pathways on beta-MnO2(1 1 0) and (101) surfaces are investigated based on density functional theory (DFT) with Vienna Ab-initio Simulation Package (VASP). The calculation results have shown that NO prefers to be adsorbed on beta-MnO2(1 1 0) instead of beta-MnO2(1 0 1) surface. The analysis results of density of states and differential charge density indicate that the interaction between NO and beta-MnO2(1 1 0) surface is stronger and the adsorbed NO had more charge transfer with beta-MnO2(1 1 0) surface. The effective activation energies of the possible NO dissociation pathways on the beta-MnO2(1 1 0) and (101) surfaces are 2.57 and 3.07 eV, respectively. The lower energy barrier on beta-MnO2(1 1 0) must be associated with the bridge adsorption of NO and more electrons transfer from NO to the surface, which is conducive to the breaking of N-O bond.

Automated summary

The study investigated the adsorption and dissociation pathways of NO on different crystal surfaces of beta-MnO2, with results indicating that NO prefers to adsorb on the beta-MnO2(110) surface, showing stronger interaction and more charge transfer compared to the (101) surface. The lower energy barrier for NO dissociation on beta-MnO2(110) is attributed to bridge adsorption of NO and increased electron transfer, facilitating N-O bond breaking.