Insight into the Mechanism of Reverse Water-gas Shift Reaction and Ethanol Formation Catalyzed by Mo6S8-TM Clusters

Recent Advances in Supported Metal Catalysts and Oxide Catalysts for the Reverse Water-Gas Shift Reaction

“…DFT calculations indicate that the formation of COOH * over Mo 6 S 8 -TM (TM = Pd, Pt, Ag) nanoclusters by the binding of the H * atom to the O atom of followed by its decomposition to CO is very favorable. Note that the COOH * dissociation over Mo 6 S 8 -Ag is the rate-determining step in the overall process, whereas the rate-determining step of Mo 6 S 8 -Pd and Mo 6 S 8 -Pt in the carboxyl pathway is the transition step of the H 2 dissociation (Zheng et al, 2017 ). Moreover, DFT calculations show that the RWGSR complies with a carboxyl mechanism over a Ni 5 /YSZ (111) catalyst through the identification of the structures and calculation of the energies of the intermediate state and two transition states, as shown in Figure 3 .…”

“…The reverse water-gas shift reaction (RWGSR) is an indispensable part of CO 2 utilization because it is a non-fossil route for providing feedstock for important chemical processes, such as methanol synthesis (Gao et al, 2016 ; Huš et al, 2017 ), Fischer-Tropsch synthesis (Riedel et al, 1999 ), and Monsanto/Cativa acetic acid synthesis (Maitlis et al, 1996 ; Jones, 2000 ). When it is used as an intermediate step in the direct thermochemical transformation of CO 2 to hydrocarbons, such as methane (Sahebdelfar and Takht Ravanchi, 2015 ; Avanesian et al, 2016 ), ethanol (Sahebdelfar and Takht Ravanchi, 2015 ), low-carbon olefin (Liu et al, 2008 ; Zheng et al, 2017 ), and dimethyl ether (Centi and Perathoner, 2009 ), the RWGSR renders the process more practical. An important workable application of the RWGSR is associated with scarce H 2 reutilization in the Mars Exploration Program, in which it could regenerate H 2 O more easily for astronauts to utilize (Avanesian et al, 2016 ).…”

Non‐Dissociative Activation of Chemisorbed Dinitrogen on One or Two Vanadium Atoms Supported by a Mo6S8 Cluster

“…More interestingly, single metal atom supported on Mo 6 S 8 may serve as ideal models of single‐atom catalysis to study the detailed catalytic mechanisms at a molecular level. Various reactions have been explored through this model, including ethanol steam reforming catalysed by Co 1 /Mo 6 S 8 , [26] methanol synthesis from CO 2 and H 2 on (K, Ti, Co, Rh, Ni, and Cu) 1 /Mo 6 S 8 , [27] direct conversion from methane to methanol in water stream by (K, Ti, Fe, Co, Ni, Cu, Rh) 1 /Mo 6 S 8 , [28] ethanol synthesis on Ni 1 /Mo 6 S 8 , [29] reverse water−gas shift reaction on (Rh, Pd, Pt, Ag) 1 /Mo 6 S 8 , [24a,30] and ethanol steam reforming on (Pt, Pd, and Co) 1 /Mo 6 S 8 [26,31] . Single atoms doped in Mo 6 S 8 may also act as promoters, as in reactions of CH 4 and H 2 S on (K, Ni, Cl) 1 /Mo 6 S 8 [32]…”

Ab Initio Study of the C–O Bond Dissociation in CO2 Reduction by Redox and Carboxyl Routes on 3d Transition Metal Systems

“…23,24 Also, density functional theory (DFT) calculations point to COOH dissociation as the rate-determining step along the carboxyl route on Pt and Ni substrates. 25,26 Most of the experimental studies give more attention to the effect of the oxides as supports than to the TM effect on the competition between routes. 8,27 Meanwhile, a few DFT studies reported this kind of information by comparing the redox and carboxyl paths on different compact and open TM surfaces, e.g., Fe(100), Co(100), Ni(100), Ni(111), Cu(100), Cu(111), Rh(111), Pd(111), Ag(111), and Pt(111).…”