The role of exposed silver in CO oxidation over MgO(0 0 1)/Ag(0 0 1) thin films

Synergistic Catalytic Effect of Ag and MgO Nanoparticles Supported on Defective BN Surface in CO Oxidation Reaction

Micron-sized supports of catalytically active nanoparticles (NPs) can become a good alternative to nanocarriers if their structure is properly tuned. Here, we show that a combination of simple and easily scalable methods, such as defect engineering and polyol synthesis, makes it possible to obtain Ag and MgO nanoparticles supported on defective hexagonal BN (h-BN) support with high catalytic activity in the CO oxidation reaction. High-temperature annealing in air of Mg-containing (<0.2 at.%) h-BN micropellets led to surface oxidation, the formation of hexagonal-shaped surface defects, and defect-related MgO NPs. The enhanced catalytic activity of Ag/MgO/h-BN materials is attributed to the synergistic effect of h-BN surface defects, ultrafine Ag and MgO NPs anchored at the defect edges, and MgO/Ag heterostructures. In addition, theoretical simulations show a shift in the electron density from metallic Ag towards MgO and the associated decrease in the negative charge of oxygen adsorbed on the Ag surface, which positively affects the catalytic activity of the Ag/MgO/h-BN material.

CO oxidation on inverse Ce6O12/Cu(111) catalyst: role of copper-ceria interactions

The surface structures, O₂ adsorption, and CO oxidation reaction properties of Ce₆O₁₂/Cu(111) have been investigated using density functional theory including on-site Coulomb corrections (DFT + U). Results show that the supported ceria nanoparticles would gain electrons from the Cu(111) surface, and the Ce⁴⁺ are reduced to Ce³⁺. In addition, the oxygens at the interface have been largely activated, resulting in much low formation energy of O vacancies. For the CO oxidation reaction, two possible pathways are investigated, CO reacts with the O₂ molecule adsorbed on Ce³⁺ and the lattice O at the interface, respectively. It has been found that CO reacting with the lattice O atom gives a lower reaction barrier than that of adsorbed O₂ on Ce³⁺. These results are important for further understanding of the role of different active sites on the inverse CeO_x/Cu(111) surface structure.

A DFT study of (WO3)3 nanoclusters adsorption on defective MgO ultrathin films on Ag(001)

The structures and electronic properties of (WO₃)₃ nanocluster adsorption on defective MgO ultrathin films supported on Ag(001) metal surfaces have been investigated by means of density functional theory (DFT) calculations including dispersion interactions.

Generation of highly reactive oxygen species on metal-supported MgO(100) thin films

A series of highly reactive oxygen species are formed with the assistance of water on an insulating surface.