High-Pressure NO-Induced Mixed Phase on Rh(111): Chemically Driven Replacement

Abstract

The interaction between nitric oxide (NO) and Rh(111) surface has been investigated by a combination of near-ambient-pressure X-ray photoelectron spectroscopy, low energy electron diffraction, and density functional theory calculations. Under lowtemperature and ultrahigh vacuum conditions, our experimental and computational results are consistent with the previous reports for NO adsorption phases on Rh(111). While at room temperature and upon exposure to gaseous NO of 100 mTorr, NO molecules partially dissociate followed by chemical removal of atomic nitrogen by NO from the surface, and the remaining atomic oxygen and NO form a NO/O mixed phase. Interestingly, this mixed phase is stable even after NO evacuation and shows a well-ordered (2 × 2) periodicity. These observations provide a new insight into the NO/Rh(111) system under nearambient-pressure condition.

How Rh surface breaks CO2 molecules under ambient pressure

“…10 ). Moreover, the evolved intermediate species cannot be classified as an atomic O* at the hollow site of Rh(111) surface in the literature 50 , 51 . Taken together, the unusual features under CO 2 (g) conditions imply that the partial chemical species of adsorbate molecules may occupy atop, bridge, and hollow sites on the Rh surface as intermediates.…”

“…10). Moreover, the evolved intermediate species cannot be classified as an atomic O* at the hollow site of Rh(111) surface in the literature 50,51 . Taken Table 2).…”

In situ analysis of catalytically active Pd surfaces for CO oxidation with near ambient pressure XPS

“…For the CO oxidation, we performed NAP-XPS experiments at the undulator soft-X-ray beamline BL-13A [25]. The combination of BL-13A and our NAP-XPS system provided us with reasonably high-resolution NAP-XP spectra which enable us to understand catalytically active surfaces [21][22][23]26] and high-density adsorption phases [27][28][29] under near ambient pressure conditions.…”

The Structure of the Active Pd State During Catalytic Carbon Monoxide Oxidization

“…The fitting included the Pd 3d 5/2 metal peak, an asymmetric shape that incorporates the asymmetry expected for a metal peak, and the Pd CO 2√2×√2 adsorbed peak based on the pure metal, centered at 334.9 (±0.05) eV. 28 , 29 For the oxide peak, a Gaussian–Lorentzian peak shape was used at 336.5 (±0.05) eV. The peak positions and assignments of the metal and oxide peaks are in good agreement with previous studies 30 , 31 after correction for the recoil effect caused by the high-energy X-rays.…”