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Mo2C is an effective catalyst for chemical CO2 upgrading via reverse water-gas shift (RWGS). In this work, we demonstrate that the activity and selectivity of this system can be boosted by the addition of promoters such as Cu and Cs. The addition of Cu incorporates extra active sites such as Cu⁺ and Cu° which are essential for the reaction. Cs is a...
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... C1 s and O1 s spectra for Mo 2 C-based catalysts are also shown in Fig. 2. For the C 1 s spectra (Fig. 2(A)), peaks at 283.5 ± 0.1 eV are assigned to carbidic carbons in Mo 2 C [35]. It can be seen that no car- bidic carbon was detected on the surface of the commercial Mo 2 C catalyst, which is in accordance with Mo XPS spectra, indicating that the Mo 2 C on the surface of catalyst was completely oxidized. ...
Context 2
... C1 s and O1 s spectra for Mo 2 C-based catalysts are also shown in Fig. 2. For the C 1 s spectra (Fig. 2(A)), peaks at 283.5 ± 0.1 eV are assigned to carbidic carbons in Mo 2 C [35]. It can be seen that no car- bidic carbon was detected on the surface of the commercial Mo 2 C catalyst, which is in accordance with Mo XPS spectra, indicating that the Mo 2 C on the surface of catalyst was completely oxidized. The major peaks at 284.6 ± 0.1 eV ...
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This work analyses the catalytic activity displayed by Cu/SiO2, Cu-Fe/SiO2 and Cu/FSN (Fe-SiO2 nanocomposite) catalysts for the Reverse Water Gas Shift reaction. Compared to Cu/SiO2 catalyst, the presence of Fe resulted on higher CO’s selectivity and boosted resistances against the constitution of the deactivation carbonaceous species. Regarding th...
Citations
... eV to Mo 6 + . [47,48] Overall, the XPS data suggests that polysulfides interact with the MoO 3 particles by a spontaneous redox mechanism that leads to a surface reduction of Mo 6 + to Mo 4 + /Mo 3 + that parallels the formation of oxidized sulfur containing species, like sulfite and sulfate. ...
Electrochemical energy storage systems based on sulfur and lithium can theoretically deliver high energy with the further benefit of low cost. However, the working mechanism of this device involves the dissolution of sulfur to high‐molecular weight lithium polysulfides (LiPs with general formula Li2Sn, n≥4) in the electrolyte during the discharge process. Therefore, the resulting migration of partially dissociated LiPs by diffusion or under the effect of the electric field to the lithium anode, activates an internal shuttle mechanism, reduces the active material and in general leads to loss of performance and cycling stability. These drawbacks poses challenges to the commercialization of Li/S cells in the short term. In this study, we report on the decoration of reduced graphene oxide with MoO3 particles to enhance interactions with LiPs and retain sulfur at the cathode side. The combination of experiments and density functional theory calculations demonstrated improvements in binding interactions between the cathode and sulfur species, enhancing the cycling stability of the Li/S cells.
... This reinforces our hypothesis that Cs suppresses methanation in Ni-based catalysts opening a new route for typical Sabatier catalysts to become switchable Methanation/ RWGS systems as reported by our team [9]. Cs addition results in an electron-rich surface favouring CO desorption and hence the selectivity towards CO [42]. CO 2 conversion is also affected being significantly lower in comparison to the non-doped sample. ...
... In addition, the presence of Cu 4 O 3 species observed in HR-TEM is supported by XPS, as the addition of Cs seems to help the stabilization of a different type of copper species with lower electron density. The presence of this new specie could be the reason of the difference in the catalytic activity of the two copper base catalyst, enhancing CO 2 adsorption and activation [42]. ...
In the context of CO2 valorisation, the reverse water–gas shift reaction (RWGS) is gathering momentum since it represents a direct route for CO2 reduction to CO. The endothermic nature of the reaction posses a challenge when it comes to process energy demand making necessary the design of effective low-temperature RWGS catalysts. Herein, multicomponent Cs-promoted Cu, Ni and Pt catalysts supported on TiO2 have been studied in the low-temperature RWGS. Cs resulted an efficient promoter affecting the redox properties of the different catalysts and favouring a strong metal-support interaction effect thus modulating the catalytic behaviour of the different systems. Positive impact of Cs is shown over the different catalysts and overall, it greatly benefits CO selectivity. For instance, Cs incorporation over Ni/TiO2 catalysts increased CO selectivity from 0 to almost 50%. Pt-based catalysts present the best activity/selectivity balance although CuCs/TiO2 catalyst present comparable catalytic activity to Pt-studied systems reaching commendable activity and CO selectivity levels, being an economically appealing alternative for this process.
... The β-Mo2C phase formed after carburization at a temperature of 650 °C or higher (blue curves). 29 There was no obvious difference in the XRD patterns J u s t A c c e p t e d Carbon Future 11 when the temperature was further increased to 800 °C, thus 650 °C was identified as the preferred carburization temperature for making nano-size β-Mo2C catalysts. The intensity of the broad peak at 22° 2θ (marked by the asterisks) slightly increased as the carburization temperature was raised, indicating the gradual formation of graphitic carbon species. ...
... After molybdenum carbide catalysts were discovered to exhibit unique catalytic performance similar to noble metals in CO 2 reforming of CH 4 and water-gas shift reaction 10-13 , they have been employed as new catalysts for the RWGS reaction [14][15][16][17][18][19][20][21][22][23][24][25][26] . It was observed that monometallic Mo 2 C and bimetallic Co-Mo 2 C were more active and selective for CO 2 conversion to CO than precious metal based bimetallic catalysts (PtCo/CeO 2 and PdNi/CeO 2 ) 23 . ...
... However, traditional Cu catalysts, such as Cu/SiO 2 , tend to deactivate dramatically under working conditions due to the segregation of supported Cu particles at temperatures exceeding 280 C 30 . Notably, a Cu/β-Mo 2 C catalyst exhibited excellent catalytic activity, with mass specific rate about 5 times higher than that of the commercial Cu/ZnO/Al 2 O 3 catalyst 16,24 . Moreover, Cu/β-Mo 2 C demonstrated stability not only under steady-state conditions but also under start-up cool-down conditions. ...
... Finally, the catalytic performance of Cu/αβ-Mo x C (1/22) obtained through the resinbased carbothermal reduction method in this work was compared with that of Cu/β-Mo 2 C (with an optimized Cu loading of 1 wt% 16,24 ) under similar conditions (Fig. 6). It is evident that they exhibited similar CO 2 conversion in the temperature range of 250-550 °C, but Cu/αβ-Mo x C displayed higher CO selectivity (lower CH 4 selectivity) compared to Cu/β-Mo 2 C. Furthermore, the RWGS performance of Cu/αβ-Mo x C (1/22) was compared with other catalysts reported in the literature. ...
The Mo carbide has been widely studied as a promising catalyst system for reverse
water-gas shift reaction (RWGS). In this study, a novel Cu-doped Mo carbide, denoted as
Cu/αβ-MoxC, was synthesized through a resin-based carbothermal reduction method, and
its structure was characterized using XRD, BET, SEM and TEM techniques. The catalyst’s Mo carbide component consisted of α-MoC1–x and β-Mo2C phases, and the Cu/Mo
molar ratios of 1/36, 1/22, 1/13, and 1/9 were considered. Among these catalysts,
Cu/αβ-MoxC with a 1:22 Cu:Mo molar ratio exhibited the highest RWGS performance.
It is worth noting that this catalyst also demonstrated significantly higher CO selectivity compared to previously reported Cu/β-Mo2C (97.6 % vs. 89.4 %) at lower temperatures
(e.g., 250 °C), attributable to its reduced affinity with CO.
... The chemical states of Mo and C in Mo2C were investigated via XPS. Figure S3 shows the survey spectrum of Mo2C, which confirms the presence of Mo and C. The features of Mo were analyzed from the high-resolution spectrum in Figure 3(a, b) resembles the previously reported work [45]. In the spectrum of C 1s ( Figure ...
Supercapacitive behavior and energy storage properties of molybdenum carbide ceramics synthesized via ball milling technique, Ceramics International (2024),), (Dr. Bhargav. A) (bhargavoynu.ac.kr), Prof. Sufyan (shafaqataligill@yahoo.com) J o u r n a l P r e-p r o o f Graphical abstract Abstract Energy production and energy storage materials are highly in demand due to their versatility, stability, sustainability, and better conductivity. Low-cost and highly efficient electrode materials (cathode/anode) for electrochemical supercapacitors (SCs) have been highly explored in the last two decades. Herein, we have synthesized Mo2C via a facile, cost-efficient, and green approach (ball milling). This work provides a new route to synthesize Mo2C, as compared with traditional techniques, to reduce the emission of poisonous gases at high temperatures. Furthermore, a comparison of the electrochemical performance of the bulk and nanostructured Mo2C was also investigated. The obtained results proved that smaller particle sizes and higher surface area are the efficient edges for the competitive performance of nanostructured Mo2C. Electron impedance spectroscopy (EIS), galvanostatic charge/discharge (GCD), and cyclic voltammetry (CV) were used to assess the electrochemical performance of bulk and nanostructured Mo2C. Nanostructured Mo2C has delivered 206 F/g at a current density of 0.1 A/g in 3M-KOH electrolyte. Nanostructured Mo2C has shown ultra-long cyclic stability after 20000 th GCD cycles with 92% retention with 100% Coulombic efficiency. These results predicted that nanostructured Mo2C is a good electrode material for supercapacitors.
... The chemical states of Mo and C in Mo 2 C were investigated via XPS. Fig. S3 shows the survey spectrum of Mo2C, which confirms the presence of Mo and C. The features of Mo were analyzed from the highresolution spectrum in Fig. 3(a and b) [45]. In the spectrum of C 1s (Fig. S3), the peaks around 284.8 eV belong to the -C-C-bond, while the existence of -C-O and -C=O species was confirmed by peaks at 286.2 eV and 289.2 eV [46]. ...
... Zhang et al. [137] reported the preparation of Cu−Cs−MO 2 C using Cu as an accelerator and Cs as a dopant to improve the conversion and selectivity of the catalyst, respectively. It was found that the increase in CO 2 conversion was due to the addition of copper to provide more active sites for the catalyst, such as Cu + and Cu 0 . ...
The increase in carbon dioxide emissions has significantly impacted human society and the global environment. As carbon dioxide is the most abundant and cheap C1 resource, the conversion and utilization of carbon dioxide have received extensive attention from researchers. Among the many carbon dioxide conversion and utilization methods, the reverse water–gas conversion (RWGS) reaction is considered one of the most effective. This review discusses the research progress made in RWGS with various heterogeneous metal catalyst types, covering topics such as catalyst performance, thermodynamic analysis, kinetics and reaction mechanisms, and catalyst design and preparation, and suggests future research on RWGS heterogeneous catalysts.
... Zhang et al. [55] reported the preparation of Cu-Cs-MO2C by using Cu as accelerator and Cs as dopant to improve the conversion and selectivity of the catalyst, respectively. It is found that the increase of CO2 conversion is due to the addition of copper to provide more active sites for the catalyst, such as Cu+ and Cu°. ...
The increase in carbon dioxide emissions has a significant impact on human society and the global environment. As the most abundant and cheap C1 resource, the conversion and utilization of carbon dioxide has received extensive attention from researchers. In many methods of carbon dioxide conversion and utilization, the reverse water gas conversion reaction is considered to be one of the most effective ways. In this paper, the research progress of reverse water gas conversion reaction in recent years is introduced.
... This process is the redox mechanism with the Cu-based catalyst involving CO 2 reduction, the ratedetermining step, and active sites in RWGS reactions. CO 2 oxidizes into Cu 0 to produce Cu + , which improves the CO selectivity by 10%, whereas H 2 reduces the Cu + to form Cu 0 to generate H 2 O [306,333]. The investigation of the morphological effect shows that Cu/CeO 2 nanorods exhibit the highest CO 2 conversion compared with Cu/CeO 2 nanocubes and favor the strong link of metal-support interaction in generating a high density of oxygen vacancies under reducing conditions [334,335]. The rod-like morphology of CuO/CeO 2 demonstrates the highest catalytic activity and stability and achieves the thermodynamic equilibrium conversion at 350 • C [336]. ...
... A study on the role of copper as a promoter has shown an indirect effect on catalyst activity. The study reported that the addition of Cu to the Mo 2 C catalyst enhances the selectivity of CO yield [333]. The presence of Cu in MoO 3 /FAU zeolite catalysts influences the reduction step of MoO 3 to MoO 2 , thus improving the CO yield [332]. ...
On the basis of its properties, ethanol has been identified as the most used biofuel because of its remarkable contribution in reducing emissions of carbon dioxide which are the source of greenhouse gas and prompt climate change or global warming worldwide. The use of ethanol as a new source of biofuel reduces the dependence on conventional gasoline, thus showing a decreasing pattern of production every year. This article contains an updated overview of recent developments in the new technologies and operations in ethanol production, such as the hydration of ethylene, biomass residue, lignocellulosic materials, fermentation, electrochemical reduction, dimethyl ether, reverse water gas shift, and catalytic hydrogenation reaction. An improvement in the catalytic hydrogenation of CO2 into ethanol needs extensive research to address the properties that need modification, such as physical, catalytic, and chemical upgrading. Overall, this assessment provides basic suggestions for improving ethanol synthesis as a source of renewable energy in the future.
... For instance, Mo 2 C was discussed for the dissociation of H 2 and activation of the RWGS reaction. Zhang et al. [112] developed Mo 2 C as support and effectively dispersed/anchored the Cu particles over the substrate, which showed a promising resistance to high-temperature sintering. In a similar study, a series of novel catalysts based on the doping of Cs and Cu-Cs on Mo 2 C via precipitation and TPC method with 1 wt% of Cs-promoter to address the enhanced catalytic performance. ...
The enormous growth in anthropologic activities (carbon dioxide (CO2) emissions) and continuous depletion of non-renewable sources have contributed to the problem of climate change and ocean acidification. Hence, CO2 capture/utilization has been widely investigated as an alternative, eco-friendly, and sustainable energy approach. Catalytic CO2 hydrogenation has the potential to effectively produce value-added chemicals and alternative fuels, thus, alleviating global CO2 emissions and reducing harmful environmental impacts. This brief review is focusing on the potential contribution of novel heterogeneous catalysts for the synergic CO2 hydrogenation into carbon monoxide, methanol, and dimethyl ether (DME). Comprehensive/detailed discussions have been made on the enhanced catalytic performance of reverse water-gas shift (RWGS)reaction (~850oC) with emphasis on the preparation methods, catalytic supports, non-noble metallic catalysts, and synergistic reaction mechanisms. The role of the Cu-based catalytic system has been featured in enhanced reaction thermodynamics, kinetics, and mechanisms of CO2 hydrogenation. The potential applicability of bi-functional catalysts with advanced water sorbents (zeolites 3A) has been investigated for CO2 conversion to DME through the intensified sorption-enhanced process. Overall, the recent advancements in the area of structure-activity relationships in situ with characterization techniques and combined experimental catalytic measurements exhibit improved CO 2 conversion of 80%, CO selectivity of 99%, methanol selectivity of 100%, and DME selectivity of 66%. The future research interest is directed toward the operation of low-cost and highly efficient water sorbents (i.e., zeolite 13X) with methanol/DME synthesis at <250oC. Furthermore, the synthesis of bifunctional mixtures of active catalytic phase with adsorbent can be investigated in the optimized hybrid reactors with renewable energy resources for improved CO2 hydrogenation.
