Ni-CeO2/SBA-15 Catalyst Prepared by Glycine-Assisted Impregnation Method for Low-Temperature Dry Reforming of Methane

Abstract

Developing low-temperature nickel-based catalysts with good resistance to coking and sintering for dry reforming of methane (DRM) is of great significance. In this work, Ni (5 wt%) and CeO2 (5 wt%) were supported on SBA-15 porous material by glycine-assisted impregnation method to obtain Ni-CeO2/SBA-15-G catalyst. XRD and TEM results showed that the addition of glycine can effectively promote the dispersion of NiO and CeO2 in the pores of SBA-15. H2-TPR and XPS results confirmed the formation of stronger metal-support interaction. In addition, after the addition of glycine, the NixCe1−xOy solid solution content was increased significantly, meanwhile, the Ce3+ concentration was increased from 31% to 49%, accompanied by more oxygen vacancies and generation of active oxygen species. For the above reasons, Ni-CeO2/SBA-15-G had better catalytic performance in the low-temperature DRM test (20 h, 600 °C) with high GHSV (600,000 mL/gcat/h), its CH4 conversion after reaction of 20 h was 2 times that of Ni-CeO2/SBA-15-C catalyst prepared by a conventional impregnation method. TGA-DTA test also proved that Ni-CeO2/SBA-15-G almost completely eliminated carbon deposition. The above advantages of the Ni-CeO2/SBA-15-G catalyst may have originated from the complexation of glycine with metal cations and can prevent them from gathering.

Low temperature reforming of methane with CO2 over Pt/CeO2, Ni/CeO2 and Pt–Ni/CeO2 catalysts prepared by a solution-combustion method

“…Therefore, reduction patterns become broader due to the consumption of H 2 by the oxygen species engendered at the Ni/Pt interface along with Pt/Ni oxides. 13,29 The shoulder peaks between 350 and 550 °C can be associated with the hydrogen consumption for the surface active oxygen species at the interface of Ce 3+ /Ce 4+ . 29…”

“…Therefore, reduction patterns become broader due to the consumption of H 2 by the oxygen species engendered at the Ni/Pt interface along with Pt/Ni oxides. 13,29 The shoulder peaks between 350 and 550 °C can be associated with the hydrogen consumption for the surface active oxygen species at the interface of Ce 3+ /Ce 4+ . 29 Table 1 provides the comparative H 2 -consumption study between surface oxygen (350-550 °C) and bulk oxygen species (600-860 °C) for all the synthesized catalysts.…”

“…[9][10][11] DRM is highly endothermic and requires high operating temperatures (600-1000 °C), leading to active metal sintering. [12][13][14] In DRM, coke deposition mainly occurred by decomposition of methane and CO disproportionation. 15,16 Another barrier for DRM is the reverse water gas shift reaction (RWGS), which is also endothermic and decreases the H 2 /CO ratio from the anticipated value for DRM.…”

Ni-Based SBA-15 Catalysts Modified with CeMnOx for CO2 Valorization via Dry Reforming of Methane: Effect of Composition on Modulating Activity and H2/CO Ratio

“…When modifiers are introduced into the support, a negligible amount of weakly bound NiO particles that are reduced at temperatures of 300-400 • C are formed on its surface. It is noteworthy that, for Ni/CeMnO x /SBA-15 (9:1), the hydrogen consumption begins at a temperature of 230 • C, which indicates the formation of a Ce 1−y Ni y O 2−δ or Ce 1−(x+y) Mn x Ni y O 2−δ solid solution [22,45]. At the same time, the fraction of dispersed and strongly bound particles also increases as indicated by the shift of maxima in the range of 510-730 • C. For the Ni/CeMnO x /SBA-15 (9:1) catalyst, the Ni 2+ reduction maximum shifts by 80 • C, while for Ni/CeMnO x /SBA-15 (1:1) and Ni/CeMnO x /SBA-15 (1:4) the shift of the maximum in the TPR-H 2 profile is above 200 • C. Thus, the catalysts modified with CeO 2 and MnO x feature higher NiO dispersion compared to Ni/SBA-15, which agrees well with the XRD data (Table 2).…”