Role of Fe Species of Ni-Based Catalysts for Efficient Low-Temperature Ethanol Steam Reforming

Abstract

The suppression of methane and coke formation over Ni-based catalysts for low temperature ethanol steam reforming remains challenging. This paper describes the structural evolution of Fe-modified Ni/MgAl 2 O 4 catalysts and the influence of iron species on methane and coke suppression for low temperature ethanol steam reforming. Ni–Fe alloy catalysts are gradually oxidized by water to generate Ni-rich alloy and γ-Fe 2 O 3 species at steam-to-carbon ratio of 4. The electron transfer from iron to nickel within Ni–Fe alloy weakens the CO adsorption and effectively alleviates the CO/CO 2 methanation. The oxidation capacity of γ-Fe 2 O 3 species promotes the transformation of ethoxy to acetate groups to avoid methane formation and the elimination of carbon deposits for anticoking. Ni10Fe10/MgAl 2 O 4 shows a superior performance with a highest H 2 yield of 4.6 mol/mol ethanol at 400 °C for 15 h. This research could potentially provide instructions for the design of Ni-based catalysts for low-temperature ethanol steam reforming.

Recent Status in Catalyst Modification Strategies for Hydrogen Production from Ethanol Steam Reforming

“…Recently, a new scheme from non‐active metal modification Ni‐base catalysts and constructed bimetallic tactics have been attested to be effective on degrading coke deposition and ameliorating catalytic selectivity [297–303] . Wu et al [297] . describes the structural evolution of Fe‐modified Ni/MgAl 2 O 4 catalysts for ESR, and found that the electron transfers from Fe to Ni in Ni−Fe alloy weakens the CO adsorption and effectively reduces the CO/CO 2 methanation (Figure 12).…”

“…Recently, a new scheme from non-active metal modification Ni-base catalysts and constructed bimetallic tactics have been attested to be effective on degrading coke deposition and ameliorating catalytic selectivity. [297][298][299][300][301][302][303] Wu et al [297] describes the structural evolution of Fe-modified Ni/ MgAl 2 O 4 catalysts for ESR, and found that the electron transfers from Fe to Ni in NiÀ Fe alloy weakens the CO adsorption and effectively reduces the CO/CO 2 methanation (Figure 12). In addition, the γ-Fe 2 O 3 species with oxidizing ability also promotes the transformation of ethoxy to acetate groups, avoiding CH 4 formation and promoting the elimination of carbon deposits.…”

“…catalysts. [297] Reprinted with permission from Ref. [297] Copyright 2021 American Chemical Society.…”

“…(b) Ethanol conversion and products selectivity, (c) H 2 yields and (d) byproducts selectivity of NiFe/MgAl 2 O 4 catalysts with various Fe loadings at 400 °C. (e) Stability test of Ni10/MgAl 2 O 4 and Ni10Fe10/MgAl 2 O 4catalysts [297]. Reprinted with permission from Ref [297].…”

“…(e) Stability test of Ni10/MgAl 2 O 4 and Ni10Fe10/MgAl 2 O 4catalysts [297]. Reprinted with permission from Ref [297]. Copyright 2021 American Chemical Society.…”