DFT-Based Characterization of the Multiple Adsorption Modes of Nitrogen Oxides on Pt(111)

Abstract

Pt is the most common catalyst for NO oxidation to NO 2 , a key reaction in NO x remediation chemistry. In this work, density functional theory calculations and plane-wave supercell models are used to calculate the energies, charge distributions, and vibrational spectra of the stable and metastable states of adsorbed NO, NO 2 , and NO 3 on Pt(111), the most likely active metal face for this catalytic oxidation. NO, NO 2 , and NO 3 are all strong electron acceptors and bind to the Pt(111) surface via charge donation from the surface. NO and NO 2 , in particular, exhibit a variety of adsorption geometries, the most favorable at low coverage being those that maximize surface-adsorbate charge transfer through binding to multiple surface Pt. At low coverage, the order of binding energies is NO > NO 3 > NO 2 , and the oxidation of adsorbed NO to NO 2 is endothermic by 0.78 eV. Higher surface coverages favor migration of NO and NO 2 to lower-coordination surface sites due to competition for metal d charge density. These changes in surface binding configurations, along with the general decrease in surface-adsorbate bond energies associated with higher surface coverages, both tend to energetically promote NO conversion to NO 2 and are important in describing this catalytic chemistry.

Inkjet-printed gas sensors: metal decorated WO3 nanoparticles and their gas sensing properties

“…Anyhow, our results suggest that NO undergoes oxidation on our sensors, which may be due to the presence of Pt in each sample (the electrode surfaces), in addition to the other metals/metal oxides decorating the WO 3 nanoparticles. 45,[50][51][52][53][54][55][56] 3.4.2. Hydrogen sulphide -H 2 S. Dwyer et al 57 have used XPS to investigate the interactions between tungsten oxide films and H 2 S gas at 475 K, close to our sensor operation temperature of 493 K. The WO 3 film was exposed to different concentrations of H 2 S gas and after each exposure, W 4f, O 1s and S 2p spectra were recorded.…”

Surface science studies of selective catalytic reduction of NO: Progress in the last ten years

“…Several review papers have summarized the development of the studies of the surface chemistry of NO on metal crystals [144][145][146][147][148]. Adsorption of NO on Pt surfaces is highly dependent on the surface structure and proceeds preferentially on steps sites, on which NO dissociation takes place, a process that is essential for NO reduction.…”

Carbon-monoxide adsorption and dissociation on Nb(110) surface

“…on well-defined metal surfaces has been researched extensively in recent years due to the fundamental interest and practical applications [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. In the case of Nb surfaces, the high-resolution electron energy loss spectroscopy (HREELS) has been used early to explore the adsorption of NO on the Nb(1 1 0) surface by Bartke et al [18] They found that parts of NO molecules adsorbed on the metal surface stably, while parts of NO molecules were dissociated.…”