Cobalt Carbide Identified as Catalytic Site for the Dehydrogenation of Ethanol to Acetaldehyde

Abstract

Two cobalt catalysts, Co/SBA-15 and Co/SiO2, have been studied in steam reforming of ethanol (SRE). Besides the steam reforming products, ethoxide dehydrogenation to acetaldehyde is observed as one of the main reactions. Although by hydrogen treatment cobalt is reduced to the metallic state, under SRE conditions, a phase appears that has been identified as cobalt carbide and correlates with acetaldehyde production. These findings provide insights about the catalytic sites, for SRE, in cobalt catalysts. Comparison with previous results shows that these conclusions are not translatable to other cobalt catalysts, stressing the importance of the support on the catalytic behavior of cobalt.

Bimetallic Ni-Co/SBA-15 catalysts for reforming of ethanol: How cobalt modifies the nickel metal phase and product distribution

“…Surprisingly, the analysis of the TEM images of both catalysts with the higher cobalt content (2Ni-8Co and 10Co/SBA-15) makes it clear that the particle size decreases, which is more evident in the 10Co/SBA-15 catalyst, where no nickel is present. According to our previous findings [3], this unexpected redispersion of metallic particles could be related to the formation of a cobalt carbide phase, which apparently breaks the cobalt metallic particles, significantly reducing the particle size. In turn, this phenomenon seems to correlate with the higher acetaldehyde production observed in these two systems (Table 3).…”

“…Although methane steam reforming is currently the most industrial competitive process for obtaining hydrogen [1][2][3], the impact on climate of using fossil fuels, and the limited availability of methane due to the remote locations of some of the major *Manuscript Click here to view linked References natural gas fields makes the use of renewable chemicals as bioethanol a very interesting alternative to reduce the environmental impact [4,5]. This product of the biomass processing is easily available, with low toxicity and also very important, the existing infrastructure for storage and transportation is spread worldwide [6][7][8].…”

Iron-Modified Mesoporous Silica as an Efficient Solid Lewis Acid Catalyst for the Mukaiyama Aldol Reaction

“…Besides, their high surface area (800-1000 m 2 /g), uniform and tunable pore diameter (usually comprised between 2 and 15 nm), ease of surface-functionalization, and well-defined particle morphology make them potential heterogeneous catalysts for a larger variety of organic reactions. [11][12][13][14][15][16][17][18][19] Since the discovery of the Mukaiyama aldol reaction 40 years ago, different types of catalysts including both homogeneous and heterogeneous catalysts have been studied. [20][21][22][23][24][25][26] In organic synthesis, the Mukaiyama aldol reaction is an essential way to chemoselectively synthesize β-hydroxycarbonyl compounds.…”

Sonochemical synthesis of library benzodiazepines using highly efficient molecular ionic liquid supported on Fe‐MCM‐41 nanocomposites as a recyclable catalyst

“…MCM‐41 structures have hexagonal arrays of uniform channels, high surface area and pore volume and hydrothermal stability that make them as potential heterogeneous nanocatalysts to a larger variety of organic reactions . Also, the introduction of metal ingredient to MCM‐41 leads to catalyst properties enhancement, which is beneficial to organic reaction.…”

“…MCM-41 structures have hexagonal arrays of uniform channels, high surface area and pore volume and hydrothermal stability that make them as potential heterogeneous nanocatalysts to a larger variety of organic reactions. [1][2][3][4][5][6][7] Also, the introduction of metal ingredient to MCM-41 leads to catalyst properties enhancement, which is beneficial to organic reaction. In comparison to other metals, impregnation of iron species into MCM-41 is significant benefits for the use of this metal in catalysis because of Lewis acidity, cheap, low in toxicity, easily accessible, and stability of Fe (III) metal (Fe-MCM-41).…”