Catalytic Performance of Ag2O and Ag Doped CeO2 Prepared by Atomic Layer Deposition for Diesel Soot Oxidation

Abstract

Abstract:The catalytic behaviour of Ag 2 O and Ag doped CeO 2 thin films, deposited by atomic layer deposition (ALD), was investigated for diesel soot oxidation. The silver oxide was deposited from pulses of the organometallic precursor (hfac)Ag(PMe 3 ) and ozone at 200 • C with growth rate of 0.28 Å/cycle. Thickness, crystallinity, elemental composition, and morphology of the Ag 2 O and Ag doped CeO 2 films deposited on Si (100) were characterized by ellipsometry, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and field emission scanning electron microscopy (FESEM), respectively. The catalytic effect on diesel soot combustion of pure Ag 2 O, CeO 2, and Ag doped CeO 2 films grown on stainless steel foil supports was measured with oxidation tests. Nominally CeO 2 :Ag 10:1 doped CeO 2 films were most effective and oxidized 100% of soot at 390 • C, while the Ag 2 O films were 100% effective at 410 • C. The doped films also showed much higher stability; their performance remained stable after five tests with only a 10% initial reduction in efficiency whereas the performance of the Ag 2 O films reduced by 50% after the first test. It was concluded that the presence of Ag + sites on the catalyst is responsible for the high soot oxidation activity.

Influence of ALD Coating Layers on the Optical Properties of Nanoporous Alumina-Based Structures

“…On the other hand, external and internal (or pore-walls) surfaces of the NPASs can easily be modified by different techniques such as dip-coating, sol-gel, chemical vapor deposition, or atomic layer deposition to obtain nanoporous structures with the most adequate pore size, chemical surface functionalization, selective transport/rejection of ions, and molecules or optical characteristics for a specific application [17][18][19]. In particular, the surface coating of NPASs by the atomic layer deposition (ALD) technique enables its modification through a broad range of materials (metal oxides, nitrides or sulfides), and has been used to modify both the external and inner surfaces of the NPASs due to its penetration along the nanopores [20][21][22].…”

Metal-Mediated Nanoscale Cerium Oxide Inactivates Human Coronavirus and Rhinovirus by Surface Disruption

“…Ag 3d spectra ( Figure 2 D) collected for both formulations exhibited a doublet (3d 3/2 and 3d 5/2 ) centered at 368.2 and 374.2 eV, related to metallic Ag (Ag 0 ). 31 − 33 In addition, a doublet at 367.5 and 373.2 eV ascribed to Ag + is observable only for AgCNP1 (with 73.8% of silver in Ag 0 state). 31 − 33 The observed proportion of Ag 0 states suggest that silver is predominantly metallic, in agreement with the previous report 31 − 33 In the case of AgCNP2, the Ag 3d spectra are comprised of only Ag o metallic state peaks centered at 368.2 eV (Ag 3d5/2) and 374.3 eV (Ag 3d3/2).…”

“… 31 − 33 In addition, a doublet at 367.5 and 373.2 eV ascribed to Ag + is observable only for AgCNP1 (with 73.8% of silver in Ag 0 state). 31 − 33 The observed proportion of Ag 0 states suggest that silver is predominantly metallic, in agreement with the previous report 31 − 33 In the case of AgCNP2, the Ag 3d spectra are comprised of only Ag o metallic state peaks centered at 368.2 eV (Ag 3d5/2) and 374.3 eV (Ag 3d3/2). 31 − 33 It is worth emphasizing that the full-width half-maximum value for metallic Ag 0 in the Ag 3d peak is increased in both formulations (∼1.25 eV) compared to pure silver (∼150 nm diameter particles) nanopowder (∼0.76 eV) ( SI Figure S3 ).…”

Wood Protection through Plasma Powder Deposition—An Alternative Coating Process

“…The peak at 367.9 eV corresponds to the Ag(0) oxidation state [31,32]. The peak position at 367.6 eV is shifted to lower binding energies, which indicates the existence of silver in oxidation states [33,34]. Hsu et al [35] explain the shift to a lower binding energy by a slight oxidation of the silver surface.…”