Unravelling the Catalytic Activity of MnO₂, TiO₂, and VO₂ (110) Surfaces by Oxygen Coadsorption on Sodium-Adsorbed MO₂ {M = Mn, Ti, V}

Abstract

Metal-air batteries have attracted extensive research interest owing to their high theoretical energy density. However, most of the previous studies have been limited by applying pure oxygen in the cathode, without taking into consideration the effect of the catalyst, which plays a significant role in the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Adsorption of oxygen on (110) Na-MO 2 is investigated, using density functional theory (DFT) calculations, which is important in the discharging and charging of Na-air batteries. Adsorption of oxygen on Na/MO 2 was investigated, and it was observed that the catalysts encourage the formation of the discharge product reported in the literature, i.e., NaO 2 . The surface NaO 2 appears to have bond lengths comparable to those reported for monomer NaO 2 .

Elucidating the Adsorption and Co-adsorption of Potassium and Oxygen on (110) MnO2, TiO2 and VO2 Surfaces

“…We then adsorbed oxygen as a bridging-peroxo unit (O2 2-) shared by two Ti surface cations, which requires the least amount of charge transfer per Ti cation of any oxidation method. The mono-nuclear configuration has an adsorption energy of 0.070 eV and the bridging configuration has an adsorption energy of 0.37eV; these values indicate that the processes are endothermic, implying a non-spontaneous process [13]. The mono-nuclear configuration is the most energetically stable configuration in which oxygen molecules are adsorbed in various orientations.…”

Unraveling the Water Oxidation Mechanism on a Stoichiometric and Reduced Rutile TiO2 (100) Surface Using First-Principles Calculations

“…39 At pH = 0, peroxo or bridging oxygens have been observed experimentally and have been found to be the most stable computationally. 38,39,53,59,60 Since the orientation of the (100) surface precluded a peroxo attachment, this work explores surfaces covered with a single oxygen on each metal active site.…”

“…The surface chemistry of TiO 2 has been modeled by stoichiometric (bare) surfaces or as OH, , peroxo/bridging oxygen, − or dangling O terminated depending on the conditions under consideration . At pH = 0, peroxo or bridging oxygens have been observed experimentally and have been found to be the most stable computationally. ,,,, Since the orientation of the (100) surface precluded a peroxo attachment, this work explores surfaces covered with a single oxygen on each metal active site.…”

Untangling product selectivity on clean low index rutile TiO2 surfaces using first-principles calculations

“…23 A second structural consideration in modeling metal oxide catalysis is atomic vacancies observed in experimental materials. [54][55][56][71][72][73][74] Due to the minimal surface disorder seen in rutile crystals and DFT, most studies of rutile, [75][76][77] both (110) and other surfaces, focus on oxygen vacancies and surface coverages. 78,79 When adsorbed species are more stable than bare surfaces, this type of surface coverage can be thought of as a surface reconstruction.…”