Ανάπτυξη και χαρακτηρισμός καινοτόμων καταλυτών για την αντίδραση μετατόπισης του Co με ατμό (WGS) σε χαμηλές θερμοκρασίες και κινητική μελέτη

Liquid fuel synthesis via CO2 hydrogenation by coupling homogeneous and heterogeneous catalysis

Effect of morphological characteristics of TiO2-supported noble metal catalysts on their activity for the water?gas shift reaction

Effect of morphological characteristics of TiO 2-supported noble metal catalysts on their activity for the water–gas shift reaction

Application of Fischer-Tropsch synthesis (FTS) in the utilization of low $$\hbox {H}_{2}/\hbox {CO}$$ ratio (0.5–1.5) gas obtained from coal and biomass gasification can be done by selecting a catalyst system active for both FTS and WGS reaction. The enhancement of $$\hbox {H}_{2}$$ content depends on the extent of water gas shift (WGS) reaction and can be quantified by measuring usage ratio define as a mole of $$\hbox {H}_{2}$$ to CO converted. With an attempt to utilize low $$\hbox {H}_{2}/\hbox {CO}$$ ratio syngas bimetallic $$(\hbox {Fe}/\hbox {Co}/\hbox {SiO}_{2})$$ were prepared and compared with monometallic ( $$\hbox {Fe}/\hbox {SiO}_{2}$$ and $$\hbox {Co}/\hbox {SiO}_{2}$$ ) catalysts. The catalysts were tested in fixed bed reactor at industrial relevant FTS conditions (T: $$220{-}260\,^{\circ }\hbox {C}$$ , P: 2.0 MPa, GHSV-1.2 SL/gcat-h, $$\hbox {H}_{2}/\hbox {CO}$$ : 1–1.5). The incorporation of Fe-Co bimetallic catalyst facilitates both FT and WGS reaction because of the presence of iron and cobalt phases. Compared to monometallic catalyst there is a significant increase in CO conversion over the bimetallic catalyst. Also, the yield of $$\hbox {C}_{5+}$$ was significantly higher over bimetallic catalyst compared to iron catalyst, where olefin was the major product. Selected catalyst $$(\hbox {Fe}/\hbox {Co}/\hbox {SiO}_{2})$$ was tested for their activity toward WGS reaction. Effects of temperature, pressure, and feed composition on WGS reaction over bimetallic catalyst were studied. Lower value usage ratio (1.62 and 1.58) reveals the occurrence WGS reaction Fe-Co bimetallic catalyst at 240 $$^{\circ }\hbox {C}$$ and 260 $$^{\circ }\hbox {C}$$ . At 240 $$^{\circ }\hbox {C}$$ , 72% CO conversion, and 60% $$\hbox {C}_{5+}$$ selectivity show that the catalyst efficiently utilizes the increased $$\hbox {H}_{2}/\hbox {CO}$$ ratio in the production of liquid hydrocarbon. Synopsis: A novel Fe-Co catalyst combination has been optimised for the conversion of biomass derived syngas, having low $$\hbox {H}_{2}/\hbox {CO}$$ ratio (1– 1.5mol/mol). The addition of iron onto silica supported cobalt catalyst facilitates the WGS reaction activity for higher $$\hbox {H}_{2}/\hbox {CO}$$ ratio internally and thus improves FTS activity. $$\hbox {10Fe}/\hbox {20Co}/\hbox {SiO}_{2}$$ catalyst resulted optimum WGS and FTS activity with 72% CO conversion, and 60% $$\hbox {C}_{5+}$$ selectivity.

Strain-assisted in-situ formed oxygen defective WO3 film for photothermal-synergistic reverse water gas shift reaction and single-particle study

Comparative study for low temperature water-gas shift reaction on Pt/ceria catalysts: Role of different ceria supports

Avoiding Sabatier’s conflict in bifunctional heterogeneous catalysts for the WGS reaction

The reverse water gas shift (RWGS) reaction is an important method for converting carbon dioxide (CO2) into valuable chemicals and fuels by hydrogenation. In this paper, the catalytic activity of single-atom metal-doped (M = Pt, Ir, Pd, Rh, Cu, Ni) indium oxide (c-In2O3) catalysts in the cubic phase for the RWGS reaction was investigated using density functional theory (DFT) calculations. This was achieved by identifying metal sites, screening oxygen vacancies, followed by further calculating the energy barriers for the direct and indirect dissociation pathways of the RWGS reaction. Our results show that the single-atom dopant in the indium oxide lattice promotes the creation of oxygen vacancies on the In2O3 surface, thereby facilitating the adsorption and activation of CO2 by the oxide surface and initiating the subsequent RWGS reaction. Furthermore, we find that the oxygen vacancy (OV) formation energy on the surface of the single-atom metal doped c-In2O3(111) surface can be used as a descriptor for CO2 adsorption, and the higher the OV formation energy, the more stable the CO2 adsorption structure is. The Cu/In2O3 structure has relatively high energy barriers for both direct (1.92 eV) and indirect dissociation (2.09 eV) in the RWGS reaction, indicating its low RWGS reactivity. In contrast, the Ir/In2O3 and Rh/In2O3 structures are more conducive to the direct dissociation of CO2 into CO, which may serve as more efficient RWGS catalysts. Furthermore, microkinetic simulations show that single atom metal doping to In2O3 enhances CO2 conversion, especially under high reaction temperatures, where the formation of oxygen vacancies is the limiting factor for CO2 reactivity on the M/In2O3 (M = Cu, Ir, Rh) models. Among these three single-atom catalysts, the Ir/In2O3 model was predicted to have the best CO2 reactivity at reaction temperatures above 573 K.

Two-in-One Catalyst Turns Carbon Dioxide in Base Chemicals

CFD analysis of a hybrid sorption-enhanced membrane reactor for hydrogen production during WGS reaction

The water–gas shift (WGS) performance of 10%Ni/Al2O3, 20%Ni/Al2O3 and 10%Ni/CaO-Al2O3 catalysts was studied to reduce CO concentration and produce extra hydrogen. Ni was added onto the Al2O3 support by an impregnation method. The physicochemical properties of nickel catalysts that influence their catalytic activity were examined. The most influential factors in increasing the CO conversion for the water–gas shift reaction are Ni dispersion and surface acidity. Ni metal sites were identified as the active sites for CO adsorption. The main effect of nickel metal was reducing the adsorbed CO amount by reducing the active site concentration. The 10%Ni/Al2O3 catalyst was more active for the WGS reaction than other catalysts. This catalyst presents a high CO conversion rate (75% CO conversion at 800 °C), which is due to its high Ni dispersion at the surface (6.74%) and surface acidity, thereby favoring CO adsorption. A high Ni dispersion for more surface-active sites is exposed to a CO reactant. In addition, favored CO adsorption is related to the acidity on the catalyst surface because CO reactant in the WGS reaction is a weak base. The total acidity can be evaluated by integrating the NH3-Temperature-Programmed Desorption curves. Therefore, an enhancement of surface acidity is identified as the favored CO adsorption.

The exponential growth of greenhouse gas emissions and their associated climate change problems have motivated the development of strategies to reduce CO2 levels via CO2 capture and conversion. Reverse water gas shift (RWGS) reaction has been targeted as a promising pathway to convert CO2 into syngas which is the primary reactive in several reactions to obtain high-value chemicals. Among the different catalysts reported for RWGS, the nickel-based catalyst has been proposed as an alternative to the expensive noble metal catalyst. However, Ni-based catalysts tend to be less active in RWGS reaction conditions due to preference to CO2 methanation reaction and to the sintering and coke formation. Due to this, the aim of this work is to study the effect of the potassium (K) in Ni/CeO2 catalyst seeking the optimal catalyst for low-temperature RWGS reaction. We synthesised Ni-based catalyst with different amounts of K:Ni ratio (0.5:10, 1:10, and 2:10) and fully characterised using different physicochemical techniques where was observed the modification on the surface characteristics as a function of the amount of K. Furthermore, it was observed an improvement in the CO selectivity at a lower temperature as a result of the K-Ni-support interactions but also a decrease on the CO2 conversion. The 1K catalyst presented the best compromise between CO2 conversion, suppression of CO2 methanation and enhancing CO selectivity. Finally, the experimental results were contrasted with the trends obtained from the thermodynamics process modelling observing that the result follows in good agreement with the modelling trends giving evidence of the promising behaviour of the designed catalysts in CO2 high-scale units.

Catalytic Pd0.77Ag0.23 alloy membrane reactor for high temperature water-gas shift reaction: Methane suppression

Safe and efficient catalytic reaction for direct synthesis of CO from methylcyclohexane and CO2

Conversion of CO2 by reverse water gas shift (RWGS) reaction using a hydrogen oxyflame