Manganese Oxide as a Promoter for Copper Catalysts in CO₂ and CO Hydrogenation

Abstract

In this work, we discuss the role of manganese oxide as a promoter in Cu catalysts supported on graphitic carbon during hydrogenation of CO2 and CO. MnOx is a selectivity modifier in an H2/CO2 feed and is a highly effective activity promoter in an H2/CO feed. Interestingly, the presence of MnOx suppresses the methanol formation from CO2 (TOF of 0.7 ⋅ 10−3 s−1 at 533 K and 40 bar) and enhances the low‐temperature reverse water‐gas shift reaction (TOF of 5.7 ⋅ 10−3 s−1) with a selectivity to CO of 87 %C. Using time‐resolved XAS at high temperatures and pressures, we find significant absorption of CO2 to the MnO, which is reversed if CO2 is removed from the feed. This work reveals fundamental differences in the promoting effect of MnOx and ZnOx and contributes to a better understanding of the role of reducible oxide promoters in Cu‐based hydrogenation catalysts.

Influence of carbon support surface modification on the performance of nickel catalysts in carbon dioxide hydrogenation

“…However, it was not our aim to improve existing industrial catalyst but rather to present a series of model catalysts, allowing fundamental studies on support effects. This could be extended to, for instance the addition of another metal, such as Fe [6,40], or metal oxide promoters [35,[67][68][69] improve catalyst activity and/or stability. All data support the conclusion that the catalyst deactivation was related to a loss of Ni active surface area, due to particle growth, which was influenced by the support properties.…”

Boosting methanol productionviaplasma catalytic CO2hydrogenation over a MnOx/ZrO2catalyst

“…For the pure MnO x catalyst, the methanol selectivity and CO 2 conversion were only 2% and 3%, respectively. Dalebout et al 16 also reported that the presence of MnO x could even suppress methanol synthesis from CO 2 . Moreover, no conversion could be observed over the MnO x /C catalyst for both CO 2 and CO hydrogenation reactions even at 260 °C and 4 MPa.…”

Balancing act: influence of Cu content in NiCu/C catalysts for methane decomposition

“…We studied a series of Ni-based catalysts with varying Cu content (0–62%), using graphitic carbon as a model support to limit metal–support interaction. 40,41 This allowed us to demonstrate that the CNF growth modes of Ni and NiCu particles differ greatly, and how the rates of different steps have to be balanced to obtain a maximum carbon yield.…”