scholarly journals Selective hydrogenation of CO on Fe3S4{111}: a computational study

2017 ◽  
Vol 197 ◽  
pp. 325-336 ◽  
Author(s):  
Alberto Roldan ◽  
Nora H. de Leeuw
Keyword(s):  
Active Sites ◽  
Iron Sulfide ◽  
Computational Study ◽  
Reaction Conditions ◽  
Energy Profiles ◽  
Reverse Water Gas Shift ◽  
Ft Synthesis ◽  
Shift Reaction ◽  
Co Reduction ◽  
Water Gas

Fischer–Tropsch (FT) synthesis has been a recursive method to form valuable molecules from syngas. Metal surfaces have been extensively studied as FT catalysts; among them, iron presents several phases under reaction conditions, oxides and carbides, as active sites for the FT and reverse water gas shift reaction. We present CO reduction on an iron sulfide phase with spinel structure, Fe3S4, also considering the pathways where C–O dissociates leaving CHx species on the surface, which may feed longer aliphatic chains via the FT process. We analysed the thermodynamic and kinetic availability of each step leading to O and OH species co-adsorbed on the surface as well as the formation of H2O from the hydrogenation of the alcohol group in the molecule. This detailed analysis led to energy profiles on both active sites of the surface, and we conclude that this Fe3S4 surface is highly selective towards the formation of methanol, in full agreement with experimental results. These findings point out that the C–C bond formation on greigite takes place through a hydroxycarbene FT mechanism.

Identification of relevant active sites and a mechanism study for reverse water gas shift reaction over Pt/CeO 2 catalysts

2016 ◽  
Vol 25 (6) ◽  
pp. 1051-1057 ◽  
Author(s):  
Xiaodong Chen ◽  
Xiong Su ◽  
Binglian Liang ◽  
Xiaoli Yang ◽  
Xinyi Ren ◽  
...  
Keyword(s):  
Active Sites ◽  
Water Gas Shift ◽  
Water Gas Shift Reaction ◽  
Mechanism Study ◽  
Reverse Water Gas Shift ◽  
Shift Reaction ◽  
Water Gas

scholarly journals Active and Stable MgAl2O4 and Ni(SA)/MgAl2O4 Catalysts for the Reverse Water Gas Shift Reaction

2021 ◽  
Author(s):  
Lingling Zhang ◽  
Qi Song ◽  
Yimeng Xing ◽  
Zhichun Si ◽  
Yuxiang Liu ◽  
...  
Keyword(s):  
Active Sites ◽  
Noble Metals ◽  
Water Gas Shift ◽  
High Price ◽  
Water Gas Shift Reaction ◽  
Durability Test ◽  
Adsorption Sites ◽  
Reverse Water Gas Shift ◽  
Shift Reaction ◽  
Water Gas

Reverse water gas shift reaction (RWGS) is an important process which plays a vital role in many CO2 utilization related reactions. Noble metals are the most active catalysts in RWGS, but the high price and low reserve strangled their applications. In the present work, we reported a non-transition-metal MgAl2O4 catalyst which showed outstanding activity and stability at high temperatures in the RWGS reaction and improved performance after doping of single atomic Nin+. The catalyst can obtain 46% of CO2 conversion in durability test of 75 h at 800 °C under high weight hourly space velocities (225 000 ml g-1 h-1). The adsorption sites, possible reaction route, and effects of Nin+ single atoms on the (111) surface of MgAl2O4 for RWGS were investigated by in situ DRIFTS and DFT calculations. The results indicated that the rate determining reaction step of RWGS on MgAl2O4 and Ni (SA)/MgAl2O4 were both the reaction of OH* + H* → H2O* + *, but the energy barrier was significantly reduced after introducing single atomic Nin+. Nin+ atoms can increase the hydroxyl coverage on the surface of catalyst and Al3+ sites near the Nin+ ion are considered as the predominant active sites for RWGS reactions.

scholarly journals In Situ Conditioning of CO2-Rich Syngas during the Synthesis of Methanol

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 534
Author(s):  
Cristina Peinado ◽  
Dalia Liuzzi ◽  
Alberto Sanchís ◽  
Laura Pascual ◽  
Miguel A. Peña ◽  
...  
Keyword(s):  
Catalyst Deactivation ◽  
Water Gas Shift ◽  
Reaction Conditions ◽  
Reverse Water Gas Shift ◽  
Methanol Formation ◽  
Pre Treatment ◽  
Synthesis Of Methanol ◽  
Shift Reaction ◽  
Water Gas

The synthesis of methanol from biomass-derived syngas can be challenging because of the high CO2 content in the bio-syngas, resulting in lower kinetics and higher catalyst deactivation. This work explores the in situ pre-treatment of a CO2-rich syngas with a CO2/CO ratio equal to 1.9 through the reverse-water gas shift reaction with the aim of adjusting this ratio to a more favorable one for the synthesis of methanol with Cu-based catalysts. Both reactions take place in two catalytic beds placed in the same reactor, thus intensifying the methanol process. The water produced during syngas conditioning is removed by means of a sorbent zeolite to prevent the methanol catalyst deactivation and to shift the equilibrium towards the methanol formation. The combination of the CO2 shifting and the water sorption strategies lead to higher productivities of the catalytic bed and, under certain reaction conditions, to higher methanol productions.

Boosting reverse water-gas shift reaction activity of Pt nanoparticles through light doping of W

2021 ◽  
Author(s):  
Daiya Kobayashi ◽  
Hirokazu Kobayashi ◽  
Kohei Kusada ◽  
Tomokazu Yamamoto ◽  
Takaaki Toriyama ◽  
...  
Keyword(s):  
Pt Nanoparticles ◽  
Water Gas Shift ◽  
Solid Solution Alloy ◽  
Alloy Nanoparticles ◽  
Water Gas Shift Reaction ◽  
Reverse Water Gas Shift ◽  
Rwgs Reaction ◽  
Shift Reaction ◽  
Water Gas ◽  
First Time

We report PtW solid-solution alloy nanoparticles (NPs) as a reverse water-gas shift (RWGS) reaction catalyst for the first time. Atomic-level alloying of Pt and W significantly enhanced the RWGS reaction activity of Pt NPs.

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