Tuning reactivity layer-by-layer: formic acid activation on Ag/Pd(111)

Abstract

<p>Modified electronic structure of Ag monolayer on Pd(111) enhances reactivity of Ag towards formic acid.</p>

Significance of the Mn-Oxidation State in Catalytic and Noncatalytic Promotional Effects of MnOx Domains in Formic Acid Dehydrogenation on Pd/MnOx Interfaces

“…Thus, the first desorption window is mostly due to the mass spectroscopic fragmentation of catemeric/monomeric FA units inside the quadrupole mass spectrometer rather than catalytic FA dehydrogenation/dehydration/decomposition reactions. 8 In Figure 1, the second desorption window is centered at 192 K. The presence of a minor molecular FA desorption feature along with the appearance of intense CO 2 , D 2 O, DHO, and H 2 O signals (accompanied by D 2 , DH, and CO desorption signals observed at higher temperatures) suggests that FA is catalytically decomposed on Pd(111) at 192 K. 8,26 Various experimental 9,13,16,18 and theoretical 39−41 studies on group VIII metal surfaces such as Pd(111) reported the formation of bidentate bridging formate species upon FA exposure. Consequently, the presence of an intense m/z = 44 (CO 2 ) signal at 192 K may suggest that the Pd(111) surface can decarboxylate the formate intermediate, facilitating FA dehydrogenation.…”

“…FA decomposition on various late transition-metal surfaces such as Pd, 8−12 Rh, 13−15 Ru, 16,17 Pt, 18−20 Cu, 21−23 Co, 24 Ag, 25 as well as Pd−Ag 26 and Pd−Au 27 bimetallic systems, has been extensively studied under ultrahigh vacuum (UHV) conditions. These studies showed that many high-coordination transition-metal single-crystal surfaces were capable of carrying out FA dehydrogenation effectively.…”

Predicting X-ray Photoelectron Peak Shapes: the Effect of Electronic Structure

“…44 Similarly, an overlayer of Pd on Ag(111) gives a more symmetric line shape for the Pd 3d 5/2 region, as compared to Pd(111) and an overlayer of Ag on Pd(111) (Figure 6B). 8,11,44 The more symmetric line shape for Pd on Ag(111) is due to the lower DOS near the Fermi level due to the bonding of the Pd overlayer to Ag (Figure S13). The DFT-calculated structural models representative of the experimentally measured Pd, Ag, and PdAg materials are provided in Figure 6C.…”

“…A single-layer overlayer of Ag on Pd(111) gives a more asymmetric shape for the Ag 3d 5/2 region, as compared to Ag(111) or a single-layer overlayer of Pd on Ag(111) (Figure 6A). 8,11,44 The more asymmetric line shape for Ag on Pd(111) is due to the higher DOS near the Fermi level due to the bonding of the Ag overlayer to Pd (Figure S13). 44 Similarly, an overlayer of Pd on Ag(111) gives a more symmetric line shape for the Pd 3d 5/2 region, as compared to Pd(111) and an overlayer of Ag on Pd(111) (Figure 6B).…”

“…8,11,44 The more asymmetric line shape for Ag on Pd(111) is due to the higher DOS near the Fermi level due to the bonding of the Ag overlayer to Pd (Figure S13). 44 Similarly, an overlayer of Pd on Ag(111) gives a more symmetric line shape for the Pd 3d 5/2 region, as compared to Pd(111) and an overlayer of Ag on Pd(111) (Figure 6B). 8,11,44 The more symmetric line shape for Pd on Ag(111) is due to the lower DOS near the Fermi level due to the bonding of the Pd overlayer to Ag (Figure S13).…”