Fe-oxide/Al2O3 for the enhanced activity of H2S decomposition under realistic conditions: Mechanistic studies by in-situ DRIFTS and XPS

In Situ Spectroscopic Studies of NH3 Oxidation of Fe-Oxide/Al2O3

“…In Figure f, the Fe 2p 3/2 spectrum is shown with a peak deconvolution based on the Gupta and Sen (GS) method, which considers various possible factors related to the peak broadening of Fe 2p (e.g., electrostatic interactions, L-S coupling between unpaired 3d electrons in a photoionized Fe cation and its 2p hole, and crystal field interactions). , Using the GS method, six independent componentsprepeak, surface peak, and multiple peaks 1 to 4 ranging from 708.5 to 713.8 eVwere required to fit an Fe 2p 3/2 spectrum of a single phase of Fe-oxide, and each phase of Fe-oxide had unique ratios among peaks 1–4 . In our Fe-oxide/Al 2 O 3 , ratios among peaks 1–4 were 22, 35.89, 19.14, and 22.97%, respectively, which did not perfectly match any of single phase of Fe-oxide, implying that our Fe-oxide nanoparticles were instead a mixture of various Fe-oxide phases (e.g., FeO, Fe 2 O 3 , Fe 3 O 4 , FeOOH, ...). ,, Raman spectroscopy analysis of the Fe-oxide/Al 2 O 3 could also indicate the coexistence of various phases of Fe-oxide (Figure S4). Although the additional small component at 707 eV can be attributed to either Fe carbide or metallic Fe, its relative composition was less than 10%.…”

“…Fe-oxide nanoparticles were deposited on Al 2 O 3 using temperature-regulated chemical vapor deposition (tr-CVD). − , The tr-CVD is a simple one-pot approach to incorporate small metal oxide nanoparticles into a porous substrate via diffusion of metal precursor throughout the porous network and its subsequent oxidation to metal oxide species. This method can be more environmentally friendly than liquid phase methods because it does not require any organic solvent.…”

“…This technique can be applied to various other substrates including SiO 2 , zeolite, and TiO 2 . 22,29,30 Inside the tr-CVD chamber, the Fe precursor ferrocene, Fe(Cp) 2 , (Aldrich) and Al 2 O 3 beads (bead size: 1 mm; mean pore size: 11.6 nm, Sasol) were placed separately. In the first step, the Fe precursors evaporated and diffused into the entire porous network of Al 2 O 3 at 60 °C over 2 h. In the second step, the diffused ferrocene molecules oxidized into Fe-oxide nanoparticles at 200 °C for 12 h. In the present work, 2.5 g of ferrocene and 10 g of Al 2 O 3 beads were used to prepare the Al 2 O 3 -supported Fe-oxide nanoparticles.…”

“…In the present work, simple temperature-regulated chemical vapor deposition (tr-CVD) was used to deposit catalytically active iron oxide (Fe-oxide) nanoparticles on mesoporous alumina (Al 2 O 3 ) beads in a highly dispersed manner, − and this structure was used for NH 3 removal. The Al 2 O 3 -supported Fe-oxide nanoparticles (Fe-oxide/Al 2 O 3 ) were able to oxidize NH 3 to N 2 through a hydrazine (N 2 H 4 )-mediated pathway with no harmful gas emission including NH 3 and NO x at temperatures above 400 °C.…”

Microbiologically Influenced Corrosion of Q235 Carbon Steel by Ectothiorhodospira sp.

“…As shown in the high-resolution O 1s spectrum in Figure 4 d, three distinct peaks located at 529.6, 531.3 and 535.2 eV corresponded to Fe 3 O 4 , FeOOH and bacteria [ 18 , 19 ], respectively. In the high-resolution S 2p spectrum, three distinct peaks centered at 161.2, 162.4 and 164.9 eV corresponded to FeS 2 , Fe 1−x S and S, respectively ( Figure 4 e) [ 20 ]. In the high-resolution N 1s spectrum, peaks at 397.2, 398.4, 399.5 and 400.5 eV corresponded to nitride, pyridine-N, protein-N and pyrrole-N, respectively ( Figure 4 f) [ 18 ].…”