Steam reforming of ethanol over K promoted Co catalyst

Ogo, Shuhei; Shimizu, Takuya; Nakazawa, Yusaku; Mukawa, Kei; Mukai, Daiki; Sekine, Yasushi

doi:10.1016/j.apcata.2015.01.018

Cited by 45 publications

(26 citation statements)

References 52 publications

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“…The former may be due to the reduction of Co2O3 to Co3O4, or further to CoO. The latter is likely attributed to the reduction of Co3O4 or CoO to Co 0 [39,40], which interacted strongly with ZnO surface, and, thus, were difficult to be reduced at lower temperatures. The addition of the appropriate amount of Sc2O3 to the Co2Zn1 host further strengthened the interaction between Co n+ species and the Znx-Scy-Oz compound-oxide surface, leading to an elevating reduction-temperature of those Co n+ species (with the main TPR peak elevating to 933 K from 791 K) (Figure 7a), and stabilizing and anchoring Co n+ particles.…”

Section: H2-tprmentioning

confidence: 99%

Improved H2 Production by Ethanol Steam Reforming over Sc2O3-Doped Co-ZnO Catalysts

et al. 2017

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H 2 production by catalytically ethanol steam reforming (ESR) is an effective and prospective method for the application of fuel cells. However, the catalysts' desirable activity and stability remains an unprecedented challenge. Herein, a type of Sc 2 O 3 -doped Co-ZnO catalyst was developed by a co-precipitation method. The so-constructed Co 2 Zn 1 Sc 0.3 catalyst exhibited a superb catalytic performance compared with Co-ZnO, giving a STY(H 2 ) as high as 1.099 mol·h −1 ·g -cat −1 (data taken 100 h after the reaction started). In comparison, the pristine Co-ZnO catalyst only afforded a STY(H 2 ) of 0.684 mol·h −1 ·g -cat −1 under identical reaction conditions. Characterization results revealed that the Sc 2 O 3 dopant strengthened the electronic interaction between Co species and ZnO, which was in favour of elevating the reduction temperature of Co oxides and boosting the dispersion of the Co n+ (n = 1 or 2). The introduction of Sc 2 O 3 induced the formation of O 2− and OH − . All of these effects effectively inhibited the sintering of active Co species and markedly improved the activity and operating stability of the catalyst.

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Section: H2-tprmentioning

confidence: 99%

Improved H2 Production by Ethanol Steam Reforming over Sc2O3-Doped Co-ZnO Catalysts

et al. 2017

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“…The reaction conditions were identical to those described in our earlier report 13 for comparative purposes. Products were analyzed using GC-TCD (GC-8A; Shimadzu Corp.) with Molecular Sieve 5A packed column and GC-FID (GC-8A; Shimadzu Corp.) with a Porapak Q packed column and a methanizer (Ru/Al 2 O 3 catalyst).…”

Section: ¹1mentioning

confidence: 99%

“…The surface of Co/Sr-P after 185 min reaction was clean (only a small amount of deposited carbon was observed) while large amount of carbon nanotubes was observed over the used Co/α-Al 2 O 3 catalyst. 13 We reported earlier that the reducibility of the supported Co species decreased upon K loading on Co/α-Al 2 O 3 . 13 Llorca et al reported that the supported Co species on Co/hydrotalcite existed as Co 2+ species.…”

Section: ¹1mentioning

confidence: 99%

“…13 We reported earlier that the reducibility of the supported Co species decreased upon K loading on Co/α-Al 2 O 3 . 13 Llorca et al reported that the supported Co species on Co/hydrotalcite existed as Co 2+ species. 14,15 These reports suggested that cationic Co 2+ species (i.e.…”

Section: ¹1mentioning

confidence: 99%

“…13 Actually, Co 0 species is known as an active species for carbon nanotube and carbon nanofiber formations (i.e. coke formation).…”

Section: ¹1mentioning

confidence: 99%

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Coke Resistance of Sr-Hydroxyapatite Supported Co Catalyst for Ethanol Steam Reforming

2017

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Co/Sr-hydroxyapatite catalyst (Co/Sr 10 (PO 4 ) 6 (OH) 2 : Co/ Sr-P) shows high activity and low carbon formation on ethanol steam reforming. H 2 -TPR measurements revealed that the Co species supported on Co/Sr-P was reduced only slightly more than that on typical Co/α-Al 2 O 3 . XAFS measurements revealed that Co 2+ species was observed mainly on the Co/Sr-P catalyst after H 2 -reduction at reaction temperature of 823 K. Co 2+ , i.e. CoO particle, on Co/Sr-P catalyst plays an important role as an active site for ethanol steam reforming with high coke resistance.Keywords: Hydrogen production | Hydroxyapatite support | Coke resistanceBiomass-derived ethanol (bioethanol) is anticipated as an important renewable resource.1 Especially, direct production of hydrogen by ethanol steam reforming is being developed intensively as a highly efficient energy production process. 2,3Moreover, since ethanol steam reforming is an endothermic reaction, as shown in eq 1, the reformate has a higher heating value of about 1450.9 kJ mol ¹1 (1277.4 for ethanol ¦H c + 173.5) after ethanol steam reforming. Therefore, ethanol steam reforming might increase the exergy rate considerably. 4 The exergy rate is defined as the ratio of Gibbs free energy (potential useful work) over the combustion enthalpy (energy supplied). Development of highly active and selective catalysts for ethanol steam reforming has been pursued actively. Among transition-metal catalysts, Co-based catalysts have been used extensively because of their higher activity and lower cost than those of noble metal catalysts.511 However, catalyst deactivation by coke formation presents an important difficulty. Therefore, the suppression of coke formation is strongly desired. Two solutions have been proposed for suppressing coke formation in ethanol steam reforming over Co-based catalysts: addition of another element 8,1014 and controlling the catalytic support. 6,7,1416 Reportedly, the use of basic supports (CeO 2 , ZnO, Mg-Al hydrotalcite, perovskite oxides, etc.) can suppress formations of coke and by-products effectively. The substituted hydroxyapatite supports were prepared using a hydrothermal method according to a published procedure with some modifications. 2022 The crystalline structure was confirmed using powder X-ray diffractometry (XRD). These XRD patterns were attributed to each hydroxyapatite with a single phase (not shown). Samples of the prepared M-phosphate and M-vanadate hydroxyapatite (M = Ca and Sr) supports are designated as Ca-P, Sr-P, Ca-V, and Sr-V.The Co catalysts supported on the hydroxyapatite supports were prepared using an impregnation method. Co(NO 3 ) 2 ¢6H 2 O was used as a metal precursor. The Co loading amount was 5 wt %. The hydroxyapatite support was mixed with distilled water in vacuo at room temperature for 2 h using a rotary evaporator. Then aqueous solution of Co precursor was added and stirred for 2 h. The obtained solution was then evaporated under heating and stirring. Subsequently, the obtained powder was dried at 393 K overnigh...

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Catalytic Hydrogen Production from Bioethanol

Song

2017

Hydrogen Production Technologies

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Steam reforming of ethanol over K promoted Co catalyst

Cited by 45 publications

References 52 publications

Improved H2 Production by Ethanol Steam Reforming over Sc2O3-Doped Co-ZnO Catalysts

Improved H2 Production by Ethanol Steam Reforming over Sc2O3-Doped Co-ZnO Catalysts

Coke Resistance of Sr-Hydroxyapatite Supported Co Catalyst for Ethanol Steam Reforming

Catalytic Hydrogen Production from Bioethanol

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