Reactive removal of surface oxygen by H2, CO and CO/H2 on a Au/CeO2 catalyst and its relevance to the preferential CO oxidation (PROX) and reverse water gas shift (RWGS) reaction

Wang, Lu‐Cun; Widmann, Daniel; Behm, R. Jürgen

doi:10.1039/c4cy01030b

Cited by 45 publications

(41 citation statements)

References 89 publications

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“…From previous TAP reactor studies on Au/TiO2 as well as on Au/CeO2 it is already known that the efficiency of H2 for active oxygen removal is considerably lower compared to CO [35,42]. The H2 consumption during a single pulse is, accordingly, too low to be resolved in these measurements, and the same is true for the formation of water during exposure to H2 or CO/H2 pulses at 80 °C [35].…”

Section: Active Oxygen Removal By Co and Hmentioning

confidence: 72%

“…This was already demonstrated by the much higher number of H 2 pulses needed for the complete removal of the available active oxygen species compared to reaction with CO in multi-pulse TAP reactor experiments (see Section 2.1 and Refs. [35,42]). Considering the selectivity of about 50% in the presence of 89% H 2 (CO/H 2 ratio of 1/8), this difference in the efficiency for O act removal can be estimated to be about 8.…”

Section: Active Oxygen Removal By Co and Hmentioning

confidence: 99%

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Competition of CO and H2 for Active Oxygen Species during the Preferential CO Oxidation (PROX) on Au/TiO2 Catalysts

2016

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Aiming at an improved mechanistic understanding of the preferential oxidation of CO on supported Au catalysts, we have investigated the competition between CO and H 2 for stable, active oxygen (O act ) species on a Au/TiO 2 catalyst during the simultaneous exposure to CO and H 2 with various CO/H 2 ratios at 80˝C and 400˝C by quantitative temporal analysis of products (TAP) reactor measurements. It is demonstrated that, at both higher and lower temperature, the maximum amount of active oxygen removal is (i) independent of the CO/H 2 ratio and (ii) identical to the amount of active oxygen removal by CO or H 2 alone. Hence, under preferential CO oxidation (PROX) reaction conditions, in the simultaneous presence of CO and H 2 , CO and H 2 compete for the same active oxygen species. In addition, also the dependency of the selectivity towards CO oxidation on the CO/H 2 ratio was evaluated from these measurements. Consequences of these findings on the mechanistic understanding of the PROX reaction on Au/TiO 2 will be discussed.

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Section: Active Oxygen Removal By Co and Hmentioning

confidence: 72%

Section: Active Oxygen Removal By Co and Hmentioning

confidence: 99%

Competition of CO and H2 for Active Oxygen Species during the Preferential CO Oxidation (PROX) on Au/TiO2 Catalysts

2016

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“…Especially, the low stability of SiO 2 against the hydrothermal condition may arouse concerns. To evaluate the stability of Au@SiO 2 /Ti-800 in the presence of water, reverse water gas shift (RWGS), a typical high-temperature reaction that has attracted increasing interest in recent years due to its importance in CO 2 activation and utilization 57,58 , was further studied. As shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Boosting the catalysis of gold by O2 activation at Au-SiO2 interface

Zhang

et al. 2020

Nat Commun

114

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Supported gold (Au) nanocatalysts have attracted extensive interests in the past decades because of their unique catalytic properties for a number of key chemical reactions, especially in (selective) oxidations. The activation of O 2 on Au nanocatalysts is crucial and remains a challenge because only small Au nanoparticles (NPs) can effectively activate O 2 . This severely limits their practical application because Au NPs inevitably sinter into larger ones during reaction due to their low Taman temperature. Here we construct a Au-SiO 2 interface by depositing thin SiO 2 layer onto Au/TiO 2 and calcination at high temperatures and demonstrate that the interface can be not only highly sintering resistant but also extremely active for O 2 activation. This work provides insights into the catalysis of Au nanocatalysts and paves a way for the design and development of highly active supported Au catalysts with excellent thermal stability.

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“…Numerous studies have shown that nanometer-sized gold particles supported on ceria and/or zirconia are an important catalyst for the low-temperature water-gas shift reaction [50][51][52][53][54][55][56]. But generally these studies are performed with high quantity of water (10-30%) and temperatures comprised between 150 and 350°C.…”

Section: Possibility Of a Water Gas Shift Reactionmentioning

confidence: 98%

Influence of the partner oxide on the catalytic properties of Au/Ce x Zr 1 − x highly loaded gold catalysts

Morfin

Ait-Chaou

Lomello

et al. 2015

Journal of Catalysis

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Reactive removal of surface oxygen by H₂, CO and CO/H₂ on a Au/CeO₂ catalyst and its relevance to the preferential CO oxidation (PROX) and reverse water gas shift (RWGS) reaction

Abstract: CO and H2 compete for the same active surface (lattice) oxygen species, but with a much lower reduction efficiency of H2 compared to CO and CO–H2 mixtures, during removal of active oxygen from a Au/CeO2 catalyst by H2, CO or CO/H2 at temperatures between 30 and 300 °C.

Cited by 45 publications

References 89 publications

Competition of CO and H2 for Active Oxygen Species during the Preferential CO Oxidation (PROX) on Au/TiO2 Catalysts

Competition of CO and H2 for Active Oxygen Species during the Preferential CO Oxidation (PROX) on Au/TiO2 Catalysts

Boosting the catalysis of gold by O2 activation at Au-SiO2 interface

Influence of the partner oxide on the catalytic properties of Au/Ce x Zr 1 − x highly loaded gold catalysts

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