Direct Identification of Active Surface Species for the Water–Gas Shift Reaction on a Gold–Ceria Catalyst

Fu, Xin-Pu; Guo, Li-Wen; Wang, Wei-Wei; Ma, Chao; Jia, Chun‐Jiang; Wu, Ke; Si, Rui; Sun, Lei; Yan, Chun‐Hua

doi:10.1021/jacs.8b09306

Cited by 160 publications

(158 citation statements)

References 44 publications

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“…Fu et al synthesized two different kinds of Au/Ce WGS reaction catalysts supported on the same nanorods of ceria, one with < 2 nm disordered clusters, and the other with 3-4-nm particles. The results exhibited that the disordered gold clusters had superior activity than the nanoparticles of gold [60]. Stere et al utilized nonthermal (cold) plasma activation to facilitate low-temperature WGS reaction over an Au-based/CeZrO 4 catalyst, where they concluded that the catalyst activity was comparable to that achieved through heating the catalyst up to 180°C [61].…”

Section: Noble Metal Basedmentioning

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: Noble Metal Basedmentioning

confidence: 99%

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

2020

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“…In the associative mechanism, CO and H 2 O adsorb on the catalyst to form an intermediate, which decomposes to yield CO 2 and H 2 . It has been proved that with associative mechanism, surface hydroxyl serves as the active species in Au/CeO 2 system 49,50 . In this case, two CO molecules react with two surface hydroxyl groups to form 2 CO 2 molecules and 1 H 2 molecule:…”

Section: Resultsmentioning

confidence: 99%

“…These observations matched the features of redox mechanism, assuming that H 2 O dissociated on CeO 2 oxygen vacancy to generate H 2 and active surface oxygen atoms. After H 2 O injection, we removed the surface oxygen with H 2 reduction and preserved the surface hydroxyls 50 , after which CO was purged into the system to conduct the TPSR test again. The subsequent CO treatment gave a CO 2 :H 2 ratio of 2:1, showing the typical results of associative mechanism.…”

Section: Resultsmentioning

confidence: 99%

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Construction of stabilized bulk-nano interfaces for highly promoted inverse CeO2/Cu catalyst

et al. 2019

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As the water-gas shift (WGS) reaction serves as a crucial industrial process, strategies for developing robust WGS catalysts are highly desiderated. Here we report the construction of stabilized bulk-nano interfaces to fabricate highly efficient copper-ceria catalyst for the WGS reaction. With an in-situ structural transformation, small CeO 2 nanoparticles (2–3 nm) are stabilized on bulk Cu to form abundant CeO 2 -Cu interfaces, which maintain well-dispersed under reaction conditions. This inverse CeO 2 /Cu catalyst shows excellent WGS performances, of which the activity is 5 times higher than other reported Cu catalysts. Long-term stability is also very solid under harsh conditions. Mechanistic study illustrates that for the inverse CeO 2 /Cu catalyst, superb capability of H 2 O dissociation and CO oxidation facilitates WGS process via the combination of associative and redox mechanisms. This work paves a way to fabricate robust catalysts by combining the advantages of bulk and nano-sized catalysts. Catalysts with such inverse configurations show great potential in practical WGS applications.

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“…Therefore, the catalytic behavior of SACs shall be significantly tailored by the presence of the OH groups. Moreover, since the catalytic performance of the WGS reaction is directly related to the interfacial atoms of the catalysts, which is maximized at the single atom limit, it is significant and highly desirable to develop SACs with high concentration of isolated NM atoms anchored on the oxide support for maximizing the catalytic activity of WGS reaction.…”

Section: Applicationsmentioning

confidence: 99%

Supported Noble‐Metal Single Atoms for Heterogeneous Catalysis

et al. 2019

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metal atoms are highly desirable for supported noble-metal (NM) catalysts. [2] Single-atom catalyst (SAC), defined as a catalyst composing only isolated singleatom active sites on supports, was first introduced by Zhang and co-workers in 2011. [3] Owing to the single-atom feature of active sites, SACs provide great advantages in minimizing the usage of precious metal with a 100% atom-utilization efficiency, which thus result in an improved catalytic reactivity, and have aroused extensive attention in the field of catalysis over the past few years. [4] Meanwhile, since the electronic properties of active sites greatly depend on the size and shape of metal particles, which then governs the performance of a catalyst, [5] downsizing metal nanoparticles (NPs) to single atom with the decreased low coordination and the quantized orbital of active sites, is recognized as the other important factor in tuning the catalytic performance of SACs. [5,6] However, due to the tendency of aggregation of single atoms during preactivation and under reaction procedures, utilization of metal/support interactions to immobilize single atom on supports plays a crucial role on the stability of SACs, and the development of effective synthesis strategies is indispensable to realize the distribution and chemical bonding of active sites on supports for the further applications of SACs.In particular, high density of active sites with well-defined local coordination structure to give appreciable catalytic activity/ selectivity and long-term stability are the ultimate goals in catalysis. [7] Thus, long-standing interest exists in fabricating heterogeneous catalysts that feature atomically dispersed metal atoms as active sites for catalytic processes. Even though, considerable efforts have been devoted to, and many advances have been achieved in supported NM-SACs for various heterogeneous catalytic applications, inclusive of CO oxidation, selective hydrogenation, water-gas shift, CO 2 reduction, electrocatalysis, and etc. [2b,7b,8] The achievements from recent studies have greatly contributed to the fast development of single-atom catalysis and paves the way for the rational design of efficient SACs in much broader catalytic systems.In this review, we will focus on this new kind of material, with great attention on the geometric and electronic structure of the single atom active sites, as well as its stability on supports. The recently developed strategies for synthesizing SACs with high metal loading and precise structure are also Single-atom catalysts (SACs), with atomically distributed active metal sites on supports, serve as a newly advanced material in catalysis, and open broad prospects for a wide variety of catalytic processes owing to their unique catalytic behaviors. To construct SACs with precise structures and high density of accessible single-atom sites, while preventing aggregation to large nanoparticles, various strategies for their chemical synthesis have been recently developed by improving the distribution and chemical bondi...

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Direct Identification of Active Surface Species for the Water–Gas Shift Reaction on a Gold–Ceria Catalyst

Cited by 160 publications

References 44 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

Construction of stabilized bulk-nano interfaces for highly promoted inverse CeO2/Cu catalyst

Supported Noble‐Metal Single Atoms for Heterogeneous Catalysis

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