Sour water–gas shift reaction over Pt/CeZrO2 catalysts

Silva, Ludmila P.C.; Terra, Luís E.; Coutinho, Ana C.S.L.S.; Passos, Fábio B.

doi:10.1016/j.jcat.2016.05.024

Cited by 48 publications

(19 citation statements)

References 96 publications

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“…Some reports indicate that the reducible oxides and solids providing oxygen vacancies can enhance the employed metal activity for the WGS reaction [128]. For example, García-Moncada et al presented a multicomponent catalyst designed using different active phases (Cu, Pt, or Au) and different ionic conductors for WGS reaction [129].…”

Section: Type Of Metal Oxide Supportmentioning

confidence: 99%

A review of recent advances in water-gas shift catalysis for hydrogen production

2020

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The water-gas shift reaction (WGSR) is an intermediate reaction in hydrocarbon reforming processes, considered one of the most important reactions for hydrogen production. Here, water and carbon monoxide molecules react to generate hydrogen and carbon dioxide. From the thermodynamics aspect, pressure does not have an impact, whereas low-temperature conditions are suitable for high hydrogen selectivity because of the exothermic nature of the WGSR reaction. The performance of this reaction can be greatly enhanced in the presence of suitable catalysts. The WGSR has been widely studied due do the industrial significance resulting in a good volume of open literature on reactor design and catalyst development. A number of review articles are also available on the fundamental aspects of the reaction, including thermodynamic analysis, reaction condition optimization, catalyst design, and deactivation studies. Over the past few decades, there has been an exceptional development of the catalyst characterization techniques such as near-ambient x-ray photoelectron spectroscopy (NA-XPS) and in situ transmission electron microscopy (in situ TEM), providing atomic level information in presence of gases at elevated temperatures. These tools have been crucial in providing nanoscale structural details and the dynamic changes during reaction conditions, which were not available before. The present review is an attempt to gather the recent progress, particularly in the past decade, on the catalysts for lowtemperature WGSR and their structural properties, leading to new insights that can be used in the future for effective catalyst design. For the ease of reading, the article is divided into subsections based on metals (noble and transition metal), oxide supports, and carbon-based supports. It also aims at providing a brief overview of the reaction conditions by including a table of catalysts with synthesis methods, reaction conditions, and key observations for a quick reference. Based on our study of literature on noble metal catalysts, atomic Pt substituted Mn 3 O 4 shows almost full CO conversion at 260°C itself with zero methane formation. In the case of transition metals group, the inclusion of Cu in catalytic system seems to influence the CO conversion significantly, and in some cases, with CO conversion improvement by 65% at 280°C. Moreover, mesoporous ceria as a catalyst support shows great potential with reports of full CO conversion at a low temperature of 175°C.

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Section: Type Of Metal Oxide Supportmentioning

confidence: 99%

A review of recent advances in water-gas shift catalysis for hydrogen production

2020

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“…The O 1s spectra were fitted by two peaks. The lower binding energy at~529.9 eV is ascribed to the lattice oxygen (O-I), whereas the higher binding energy at~531.9 eV is attributed to the oxygen ions with lower coordination or hydroxyl-like groups (O-II) [41,42]. The area ratios of O-II and O-I are similar, and are 0.16 on m-ZrO 2 and 0.18 on t-ZrO 2 .…”

Section: Surface Propertiesmentioning

confidence: 99%

Effect of Zirconia Polymorph on Vapor-Phase Ketonization of Propionic Acid

Ding

Zhao

2019

Catalysts

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Vapor-phase ketonization of propionic acid derived from biomass was studied at 300-375 • C over ZrO 2 with different zirconia polymorph. The tetragonal ZrO 2 (t-ZrO 2 ) are more active than monoclinic ZrO 2 (m-ZrO 2 ). The results of characterizations from X-ray diffraction (XRD) and Raman suggest m-ZrO 2 and t-ZrO 2 are synthesized by the solvothermal method. NH 3 and CO 2 temperature-programmed desorption (NH 3 -TPD and CO 2 -TPD) measurements show that there were more medium-strength Lewis acid base sites with lower coordination exposed on m-ZrO 2 relative to t-ZrO 2 , increasing the adsorption strength of propionic acid. The in situ DRIFTS (Diffuse reflectance infrared Fourier transform spectroscopy) of adsorbed propionic acid under ketonization reaction reveal that as the most abundant surface intermediates, the monodentate propionates are more active than bidentate propionates. In comparison with m-ZrO 2 , the t-ZrO 2 surface favors monodentate adsorption over bidentate adsorption. Additionally, the adsorption strength of monodentate propionate is weaker on t-ZrO 2 . These differences in adsorption configuration and adsorption strength of propionic acid are affected by the zirconia structure. The higher surface concentration and weaker adsorption strength of monodentate propionates contribute to the higher ketonization rate in the steady state.Catalysts 2019, 9, 768 2 of 15 coordination of Ti 4+ cations exposed on the surface. Stubenrauch et al. studied the reaction of formic acid and acetic acid on CeO 2 (111) and (100) surface [24]. On both surfaces, CH 2 CO was produced through acetic acid dehydration near 600 K. However, acetone was detected only on the (111) surface during acetic acid decomposition at 600 K. This result is different from that obtained by Kim et al., since Ce 4+ cations of (111) surface possess one vacancy relative to the Ce 4+ cations in the bulk. Wang et al. carried out ketonization of carboxylic acid on anatase and rutile TiO 2 , monoclinic and tetragonal ZrO 2 at 503-533 K [25,26]. They showed that the reaction activity of acetic acid was higher over anatase TiO 2 than that over rutile TiO 2 , and attributed that to the more reactive monodentate acetate present on anatase TiO 2 , whereas unreactive bidentate acetate was present on rutile TiO 2 . The effect of different nanocrystals (nanocubes, nanorods and nanopolyhedra) of CeO 2 on acetic acid ketonization was studied by Snell et al. at 503 K in the condensed phase and at 623 K in the vapor phase [27]. They found that the crystal of CeO 2 was disrupted in the condensed phase with the formation of metal carboxylate, whereas the bulk structure was maintained during the vapor phase reaction. They suggested that the morphology of CeO 2 did not have a critical influence on the reaction activity in the condensed and vapor phase. Although some work has been done on the influence of the structure, no consensus has been reached. This may be due to the different reaction conditions (condensed phase and vapor phase) via the different reaction...

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“…Unfortunately, the binding energy (B.E.) of Pt 4f 5/2 was very close to that of Al 2p in case of γ-alumina support [50]. The decomposition of such Pt 4f 7/2 and 4f 5/2 XPS peaks were used to analyze the predominant species in catalysts ( Figure S4 and Table S1).…”

Section: Structures and Properties Of Catalystsmentioning

confidence: 99%

Dehydrogenation of Propane to Propylene Using Promoter-Free Hierarchical Pt/Silicalite-1 Nanosheets

et al. 2019

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Propane dehydrogenation (PDH) is the extensive pathway to produce propylene, which is as a very important chemical building block for the chemical industry. Various catalysts have been developed to increase the propylene yield over recent decades; however, an active site of monometallic Pt nanoparticles prevents them from achieving this, due to the interferences of side-reactions. In this context, we describe the use of promoter-free hierarchical Pt/silicalite-1 nanosheets in the PDH application. The Pt dispersion on weakly acidic supports can be improved due to an increase in the metal-support interaction of ultra-small metal nanoparticles and silanol defect sites of hierarchical structures. This behavior leads to highly selective propylene production, with more than 95% of propylene selectivity, due to the complete suppression of the side catalytic cracking. Moreover, the oligomerization as a side reaction is prevented in the presence of hierarchical structures due to the shortening of the diffusion path length.

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Sour water–gas shift reaction over Pt/CeZrO2 catalysts

Cited by 48 publications

References 96 publications

A review of recent advances in water-gas shift catalysis for hydrogen production

A review of recent advances in water-gas shift catalysis for hydrogen production

Effect of Zirconia Polymorph on Vapor-Phase Ketonization of Propionic Acid

Dehydrogenation of Propane to Propylene Using Promoter-Free Hierarchical Pt/Silicalite-1 Nanosheets

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