International Journal of Hydrogen Energy 29 (2004) 1075–1081www.elsevier.com/locate/ijhydene

Hydrogen from steam reforming of ethanol in low and middletemperature range for fuel cell application

Jie Suna;b;c, Xinping Qiub, FengWua ;∗, Wentao Zhub, WendongWanga, Shaojun HaoaaSchool of Chemical and Environmental Science, Beijing Institute of Technology, Beijing 100081, China

bDepartment of Chemistry, Tsinghua University, Beijing 100084, ChinacInstitute of Chemical Defense of PLA, Beijing 102205, China

Abstract

The catalyst, Ni nano-particles supported on Y2O3, which was prepared by three methods, was studied. The structuralproperties of the catalysts were tested through X-ray di5raction and BET area. The catalyst of Ni=Y2O3 exhibits high activityfor ethanol steam reforming with conversion of ethanol of 98% and selectivity of hydrogen of 38% at 300◦C, conversion ofethanol of 98% and selectivity of hydrogen of 55% at 380◦C. With temperature increasing to and above 500◦C, the conversionof ethanol increased to 100%, but the selectivity of hydrogen did not increase so much, it was 58% at 600◦C. The catalysthas long-term stability for steam reforming of ethanol and is a good choice for ethanol processors for fuel cell applications.? 2003 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.

Keywords: Ethanol steam reforming; Hydrogen; Conversion; Selectivity

1. Introduction

In recent years, the proton exchange membrane fuel cells(PEMFC) with hydrogen as fuel has attracted many atten-tions due to its potential application in electric vehicles andpower station. The use of hydrogen as a fuel o5ers an im-portant reduction in NOx and COx emissions. There are fourbasic methods for hydrogen production at present: waterelectrolysis, gasiAcation, partial oxidation reactions of heavyoil, and steam reforming reactions [1]. Ethanol as a sourceof hydrogen has several advantages compared to other “pri-mary fuel” such as methanol, gasoline and hydrogen it-self [2]. It can be manufactured by fermentation of cropsand as such has an attractive potential because of its origin(agroproduct) and the consequent reduction in carbon diox-ide emission. Its storage, transportation, and distribution arerelatively safe and easy [1–3].

The reactions of ethanol over the surfaces of metal oxidesand metals have been studied for more than one decade

∗ Corresponding author. Tel.: +86-10-689-125-08; fax: +86-10-6845-1429.E-mail addresses: magnsun@bit.edu.cn (J. Sun),

wufeng863@bit.edu.cn (F. Wu).

now. The reforming of ethanol can be found in Refs. [1,3–17]. Reactions of ethanol dehydrogenation over noble metalmembrane [18–20], and reactions of ethanol over M=CeO2catalysts [21–23] have been studied. The catalytic proper-ties of the supported transition metal catalysts in one of thesteam reforming reactions (reaction (2) in Table 1) showthat the selectivity of H2 for the reforming reaction is in theorder: Co much greater than Ni¿Rh¿ Pt, Ru, Cu. Theproperties of the Co on di5erent supports were also stud-ied. Co=Al2O3 exhibited the highest selectivity for steamreforming of ethanol by suppression of methanation of COand decomposition of ethanol [8–11]. The studies of ethanolsteam reforming in a molten carbonate fuel cell (MCFC)utilized the catalysts from the noble metals (Pt, Rh, etc.)to CuO=ZnO=Al2O3 and NiO=CuO=SiO2 and they got verygood results: the selectivity of hydrogen of 5% Rh=Al2O3

can reach to 30.1 vol% [1,12–14]. The steam reforming ofethanol at about 300◦C over catalyst of Cu=Ni=K=�-Al2O3

has been studied by Marino et al. [15,16].Compared to methanol, ethanol has one major complica-

tion if one considers its total decomposition: it contains acarbon–carbon bond and as such requires a surface capa-ble of breaking its bond. There are at least two further re-quirements for the surface. It must be capable of oxidizing

0360-3199/$ 30.00 ? 2003 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.doi:10.1016/j.ijhydene.2003.11.004

1076 J. Sun et al. / International Journal of Hydrogen Energy 29 (2004) 1075–1081

Table 1Relative reactions of ethanol steam reforming in this work

Independent reactions which involve ethanol, water and hydrogen Selectivity (mole fraction)

CH3CHO CO2 CH4 CO H2

(1) C2H5OH + 3H2O → 6H2 + 2CO2 — 25 — — 75(2) C2H5OH + H2O → 4H2 + 2CO — — — 33.3 66.7(3) C2H5OH → H2 + CH3CHO 50 — — — 50(4) C2H5OH → H2 + CO + CH4 — — 33.3 33.3 33.3(5) C2H5OH → 3H2 + CO + C — — — 25 75Dependent reactions(6) 2CO → CO2 + C — 100 — — —(7) CO + H2O → CO2 + H2 — 50 — — 50(8) CH4 + 2H2O → CO2 + 4H2 — 20 — — 80(9) CO2 + CH4 → 2CO + 2H2 — — — 50 50(10) C2H5OH + H2O → 2H2 + CO2 + CH4 — 25 25 — 50(11) 2C2H5OH + 3H2O → 7H2 + 2CO2 + CO + CH4 — 18.2 9.1 9.1 63.6(12) 2C2H5OH + H2O → 3H2 + CO2 + CO + 2CH4 — 14.3 28.6 14.3 42.9

both carbon atoms to CO2, and in the case of hydrogenproduction, it must not be active for the oxidation of H2.Consequently, the choice of the support is very crucial. Anideal support would not favor dehydration reactions (such as�-Al2O3) and would have no (or mild) capability for otherC–C bond formation reactions [24].

Based on the above studies, we chose Ni as the supportedmetal and Y2O3 as the support. Ni has been widely usedas catalyst in hydrogenation and dehydrogenation reactionsbecause of its high activity and low cost. It is well knownthat rare earth metal oxides are the highly alkaline and arefavorable for dehydrogenation of alcohols. Y2O3 is moreactive for dehydrogenation than oxides of other elements inlanthanides. In this work, the catalyst of Ni=Y2O3 for ethanolsteam reforming for hydrogen production is studied.

2. Experimental

2.1. Catalyst preparation

Three simple methods were employed to prepare theNi=Y2O3 catalysts. In method (1), Y2O3 powder was putinto the solution of Ni(NO3)2 under continuous stirring forno less than 6 h at 90◦C. After water being dried out, thedry product was heated at 120◦C for 12 h to release NO2,then ground, sieved and heated at 500◦C for 2 h in H2 Powto reduce the NiO to Ni. In method (2), NiSO4; NaBH4 andY2O3 were used as starting materials. Y2O3 powder wasput into the solution of NiSO4 under continuous stirring,and then the solution of NaBH4 was dropped into the mix-ture of Y2O3 and the solution of NiSO4, and black looseNi was produced. Then the solid was Altrated, washed anddried out, and then heated at 500◦C for 2 h in H2 Pow. Inmethod (3), the solution of NiSO4 was dropped into the

solution of K2C2O4 under continuous stirring and NiC2O4

precipitated. During the precipitation of NiC2O4; Y2O3

powder was put into the mixture at the same time. After24 h continuous stirring, the mixture was centrifuged andwashed to eliminate SO2−

4 and K+ ions, then the productwas dried at 100◦C for 24 h. The dry product was thenground, sieved, and heated at 500◦C for 2 h in N2 Pow.NiC2O4 would decompose to Ni and CO.

X-ray powder di5raction (XRD) was carried out on aRigaku X-ray di5raction equipment, using the Cu K� radi-ation, at 40 kV and 20 mA.

The BET surface area of each catalyst was determinedby means of nitrogen physisorption, using a QuantachromeNOVA automated gas sorption instrument.

2.2. Ethanol steam reforming

The ethanol steam reforming experiments were conductedwith a Axed-bed reactor (inner diameter 16 mm) Atted in aprogrammable oven with three heat sections (Fig. 1). Thenether heat section with an operating range up to 300◦Cwas used as evaporator, and we chose 280◦C as the vapor-izing temperature to vaporize the inPuent instantly. The twoup sections were used for the reforming reactions with anoperating range up to 700◦C and 1000◦C, respectively. Inthis work, the catalyst prepared by method (1) or method(2) was previously in situ decomposed in nitrogen at 500◦Cfor 2 h and then reduced in hydrogen at 500◦C for 2 h be-fore the reforming reactions. While the catalyst preparedby method (3) only need previously in situ decomposed innitrogen at 500◦C for 2 h without hydrogen reduction be-fore the reforming reactions. The Pow rate of ethanol–watersolution was controlled as 0:05 cm3 min−1. The reformingreactions take place through the catalyst bed. The compo-nents of eRuents were out through a condenser and a dryer,

J. Sun et al. / International Journal of Hydrogen Energy 29 (2004) 1075–1081 1077

Products GCreactor

700-1000°C

300-700°C

0-300°C

catalyst bed

quartz powder

evaporator

nitrogen or hydrogenethanol solution

Fig. 1. Scheme of the reforming reactor and oven.

and then introduced to a gas chromatograph (GC). The GCwas equipped with two packed columns (Porapak, 80–100mesh, 1:5 m long; Tdx-01, 60–80 mesh, 1:5 m long) andone thermal conductive detector (TCD). The Porapak col-umn was used for the separation of C2H5OH; H2O andCH3CHO with H2 as carrier gas, the column temperaturebeing 100◦C. The Tdx-01 column was used for the separa-tion of CO; CO2; CH4; C2H4, and C2H6 with H2 as carriergas, the column temperature being 100◦C.

3. Results and discussion

It has been shown, from a thermodynamic point of view,that the steam reforming of ethanol is entirely feasible[4,5,17]. The system of steam reforming of ethanol involvesa set of response reactions which have di5erent relativefractions at di5erent operative condition. The yield of pro-duced hydrogen may be a5ected by each response reaction[5]. Therefore, the yield of hydrogen depends largely onthe operative conditions of the reforming reaction, suchas pressure, temperature, H2O=EtOH mole ratio, etc. Inorder to increase the yield of hydrogen, it is necessary toknow the e5ect of these operative conditions on the productcomponents.

3.1. Structural characteristics of Ni=Y2O3

3.1.1. XRDFig. 2 shows the XRD patterns of Ni=Y2O3 catalysts pre-

pared by three di5erent methods. The peaks labeled with thesymbol ∗ are corresponding to di5raction peaks of NiO, andthe other peaks are corresponding to that of Y2O3. No new

20 30 40 50 60 70

(220

)

(521)

(200

)

(111

)

(631)(622)(620)(600)(440)(411)

(211)

(541)

(332)

(400)

(222)

*

****

* **

*(3)

(2)

(1)

Inte

nsity

( a

.u.)

2θ (degree)

Fig. 2. XRD of the Ni=Y2O3 catalysts prepared by three methods.The peaks with symbol ∗ and vertical labels of Miller indexesare corresponding to di5raction peaks of NiO, and the peaks withhorizontal labels of Miller indexes are corresponding to that ofY2O3. (a) XRD patterns of catalyst prepared by method (1), (b)XRD patterns of catalyst prepared by method (2), (c) XRD patternsof catalyst prepared by method (3).

Table 2Crystal grain sizes of catalysts calculated in this work

Method of catalyst Y2O3 (nm) NiO (nm)

(1) 59 —(2) 71 67(3) 81 69

peaks appeared, meaning that the catalysts have only thephases of NiO and Y2O3 and no new compound was formed.The crystal size of the heterogeneous catalysts, calculatedby Scherrer formula, was listed in Table 2. The crystal sizeof Y2O3 was calculated based on his peaks with Miller in-dexes of (4 0 0) and (5 4 1). The crystal size of NiO wascalculated based on his peak with Miller indexes of (2 0 0).It can be seen that the crystal sizes of Y2O3 changed in dif-ferent methods: method (1) 59 nm, method (2) 71 nm, andmethod (3) 81 nm, respectively. The crystal size of NiO inthe catalyst prepared by method (1) was hard to calculatebecause of its too weak di5raction. The crystal sizes of NiOin the catalyst prepared by method (2) and method (3) are67 and 69 nm, respectively.

3.1.2. BETThe results of BET measurement (Table 3) indicated that

the speciAc surface area of catalyst prepared by method (3)was 52:2 m2 g−1, larger than that of the catalysts preparedbymethod (1) 26:3 m2 g−1 and bymethod (2) 17:0 m2 g−1.

1078 J. Sun et al. / International Journal of Hydrogen Energy 29 (2004) 1075–1081

Table 3Catalyst BET area tested in this work

Method of Description BET areacatalyst (m2=g)

Y2O3 9.1(1) Ni(NO3)2=Y2O3 → NiO=Y2O3 26.3(2) NiSO4=Y2O3=NaBH4 → NiO=Y2O3 17.0(3) NiC2O4=Y2O3 → NiO=Y2O3 52.2

3.2. Catalyst selectivity and conversion

Generally, the deAnitions of catalyst selectivity are dif-ferent according to the convenience for description catalyticreaction [25–28]. For the ethanol steam reforming reactions,selectivity of hydrogen was usually deAned as the mole ratioof produced hydrogen to the consumed ethanol [16]. While,for the convenience of tests, we deAned the catalyst selec-tivity as the mole fraction of each product:

SP =molPmolsp

× 100%: (1)

Here, molp represents the number of moles of each prod-uct; molsp represents the number of sum moles of products,but the number of moles of solid products (such as smallamount of coke) is not included. Catalyst activity is eval-uated in terms of ethanol conversion. We deAned ethanolconversion as

CE =molconvmolsEt

× 100%: (2)

Here, molconv represents the number of moles of con-verted ethanol; molsEt represents the number of sum molesof ethanol feed into reactor.

3.3. E7ect of the prepared methods on the selectivity ofhydrogen

Six grams of catalyst was used to test its catalysis proper-ties for the ethanol reforming reactions. Fig. 3 shows the se-lectivity of hydrogen of catalyst Ni=Y2O3 prepared by threemethods for ethanol steam reforming at 600◦C. Catalystsselectivity of hydrogen prepared by methods (1), (2), and(3) is 53.5%, 53.7% and 59.6%, respectively. The selectiv-ity of hydrogen of the catalyst prepared by method (3) wasthe highest and this maybe due to its high speciAc surfacearea. In the following sections, we used catalyst preparedby method (3) for further experiments.

3.4. E7ect of the mole ratio of H2O=EtOH on theselectivity of hydrogen

Fig. 4 shows the e5ect of the mole ratio of water andethanol (H2O=EtOH) on the selectivity of hydrogen attemperature 500◦C. At mole ratios of 3:1 and 8:1, theselectivity of H2 reaches higher values of 45% and 46.5%,

(1) (2) (3)0

10

20

30

40

50

60

SH

2(mol

%)

Methods of Catalysts

Fig. 3. Selectivity of hydrogen, over the catalysts prepared by threemethods. Experimental conditions: mass of catalyst 6 g; pellets size0.5–1 mm; H2O=EtOH mol ratio 3:1, Pow rate 0:05 cm3 min−1

(W=F = 7200 g s cm−3), P = 1 atm; T = 600◦C. (a) Selectivityof hydrogen, over the catalyst prepared by method (1) (b) Selec-tivity of hydrogen, over the catalyst prepared by method (2) (c)Selectivity of hydrogen, over the catalyst prepared by method (3).

respectively. It is interesting that there are two peak valuesin Fig. 4. From reaction (1) (in Table 1), it can be seen thatwhen the H2O=EtOH mols ratio is 3:1, the mole fraction ofhydrogen is 75%, very high. So the appearance of a peaknear mole ratio of 3:1 is reasonable. However, when moleratio reached 8:1, the extent of water–gas shift reaction (asreaction (7) in Table 1) increases when there is much ex-cess water. The shift reaction contributes to the form of thesecond peak, so we chose the H2O=C2H5OH mol ratio of3:1 in the further experiments considering the selectivity ofhydrogen and the reaction rate.

3.5. E7ect of temperature on selectivity and conversion

Typical experimental results obtained are presented inFigs. 5 and 6, in which the selectivity of each product andthe conversion of ethanol are shown as a function of reactiontemperature in the low-temperature range of 300–400◦C andmiddle temperature range of 400–650◦C. At temperature300◦C, steam reforming of ethanol has occurred apprecia-bly and the selectivity of hydrogen, methane, carbon diox-ide and carbon oxide are 38.2%, 34.3%, 18.3% and 9.2%,respectively. A slight amount of acetaldehyde was also de-tected with the selectivity of 0.02%. When the temperatureincreased from 300◦C to 380◦C, the selectivity of hydrogenincreased from 38.2% to 55.2%, while the selectivity ofmethane decreased from 34.3% to 27.8%. The selectivity ofcarbon dioxide and carbon monoxide kept decreasing from18.3% to 15% and from 9.2% to 2.0%, respectively. The

J. Sun et al. / International Journal of Hydrogen Energy 29 (2004) 1075–1081 1079

0 2 4 6 8 100

10

20

30

40

50

60

SH

2 (m

ol%

)

H2O/EtOH (mol ratio)

Fig. 4. E5ect of mol ratios of H2O=EtOH on the selectivity of hydrogen, over the Ni=Y2O3 catalyst. Experimental conditions: mass ofcatalyst 6 g, pellets size 0.5–1 mm, Pow rate 0:05 cm3 min−1 (W=F = 7200 g s cm−3); P = 1 atm; T = 500◦C.

300 320 340 360 380 400

0

10

20

30

40

50

60

70

80

90

100

SH2

CEthanol

Temperature(oC)

C (

%),

S (

mol

%)

SCH4

SCO2

SCOSCH3 CHO

Fig. 5. E5ect of low reaction temperature range (300–400◦C)on conversion of ethanol (CEtOH) and on selectivity of hy-drogen (SH2), carbon monoxide (SCO), carbon dioxide (SCO2 ),methane (SCH4 ) and acetaldehyde (SCH3CHO), obtained over theNi=Y2O3 catalyst. Experimental conditions: mass of catalyst 15 g,particle size 0.5–1 mm; H2O=EtOH mol ratio 3:1, Pow rate0:4 cm3 min−1(W=F = 2250 g s cm−3); P = 1 atm.

selectivity of acetaldehyde reached the maximum of 0.04%at 360◦C, down to the bottom value of 0.02% at 380◦C.No acetaldehyde was detected measurably above 380◦C.When the temperature increased from 380◦C to 400◦C, the

400 450 500 550 600 6500

20

40

60

80

100

SCO

SCO2

SCH4

SH2

CEthanol

C (

%),

S (

mol

%)

Temperature(oC)

Fig. 6. E5ect of middle reaction temperature range (400–650◦C)on conversion of ethanol (CEtOH) and on selectivity of hy-drogen (SH2), carbon monoxide (SCO), carbon dioxide (SCO2 ),methane (SCH4 ) and acetaldehyde (SCH3CHO), obtained over theNi=Y2O3 catalyst. Experimental conditions: mass of catalyst 15 g,particle size 0.5–1 mm; H2O=EtOH mol ratio 3:1, Pow rate0:4 cm3 min−1 (W=F = 2250 g s cm−3); P = 1 atm.

selectivity of hydrogen decreased to 42.7%, while theselectivity of methane and carbon dioxide increased to38.1% and 18.3%, respectively. The selectivity of carbonoxide kept decreasing to 0.9%.

1080 J. Sun et al. / International Journal of Hydrogen Energy 29 (2004) 1075–1081

This distribution of selectivity of each product should fol-low relative reactions in Table 1, where the selectivity ofeach product in each reaction at equilibrium was listed, butthe contribution of each reaction to the selectivity of eachproduct in the reactions system changed with di5erent op-erative conditions. In the temperature range of 300–330◦C,reactions (4), (10) and (12) seem to contribute more than theother reactions considering the selectivity (mole fraction)of the products. In this temperature range, the selectivity ofhydrogen increased from 38.2% to 46.9%, and the selectiv-ity of methane, carbon dioxide and carbon oxide decreasedfrom 34.3% to 31.9%, from 18.3% to 17.7% and from 9.2%to 3.5%, respectively, which was closely consistent withco-reactions of (4), (10) and (12). In the temperature rangeof 330–380◦C, reactions (1) and (4) should be the dominatereactions, since the selectivity of methane, carbon dioxideand carbon oxide kept decreasing, from 31.9% to 27.8%,17.7% to 15% and 3.5% to 2.0%, respectively. Only the se-lectivity of hydrogen kept increasing, from 46.9% to 55.2%.In the temperature range of 380–400◦C, the decrease of se-lectivity of hydrogen and carbon oxide contributed to theincrease of that of methane and carbon dioxide. This meansthat reaction (10) became the dominated reaction. The con-version of ethanol reached to 98% at the low temperaturerange of 300–400◦C. This high result means very goodactivity of the catalyst.

The e5ects of temperatures between 400◦C and 650◦C onthe selectivity and conversion were presented in Fig. 6. Withthe increase of the temperature, the conversion of ethanolincreased. The conversion of ethanol reached 100% whenthe temperature was 500◦C and above. However, the hydro-gen selectivity did not increase much compared with the se-lectivity at the low temperature range (300–400◦C). In thetemperature range of 400–600◦C, the selectivity of hydro-gen, carbon dioxide and carbon oxide kept increasing andreached a peak value of 58%, 20.2% and 4.9% at 600◦C, re-spectively. While the selectivity of methane kept decreasingand down to the minimum value of 16.9% at 600◦C also,which indicated the reformation of methane with H2O hadoccurred (as reaction (8) in Table 1). Here, the dependentreaction (11) (in Table 1) seems to contribute more. Withtemperature increasing to 650◦C, the selectivity of hydro-gen and carbon dioxide decreased while the selectivity ofmethane and carbon oxide increased, which indicated thatinverse water–gas shift reaction took place with tempera-ture increasing. This means that the Ni=Y2O3 catalyst is alsoactive for the inverse water–gas shift reaction.

In the temperature ranges we studied, no C2H2; C2H4 andC2H6 were not detected measurably in the reaction products,indicating that no dehydration of ethanol was taking place,as might be expected. This is due to the fact this particu-lar catalyst, which uses Y2O3 as the support material, dosenot possess dominating acidic sites, which are required forthe dehydration route [3]. In the temperature range of 300–380◦C, there had occurred the reforming reactions evidently,which proved the fact that the catalyst of Ni=Y2O3 is active

for carbon–carbon bond breaking. On the other hand, therewas a slight amount of acetaldehyde (the highest selectiv-ity is 0.04%) to be detected, which indicated two importantpossibilities: the particular catalyst Ni=Y2O3 has a mild ca-pability for dehydrogenation of ethanol and the catalyst hasvery strong ability to break the C–C bond of acetaldehydewhich is just an in-process product. In the temperature rangeof 500–650◦C, the conversion of ethanol reached 100%, atthe temperature of 600◦C, the selectivity of hydrogen ex-ceeded 58%. Under these conditions, one of the undesirableproducts was methane, which consumed hydrogen atoms.

There appeared a small amount of coke also at the middletemperature range of 400–650◦C. In our early work, Ramanspectrum of the deposition had proved that it was carbon.The TG analysis used pure ethanol as inPuent introducedby nitrogen indicated that coke deposition began at about380◦C. If the reforming temperature increased above 380◦C,the coke deposition would start very soon. Although theproduct of coke may increase the selectivity of hydrogen ingaseous products (as reaction (5) in Table 1, the selectivityof hydrogen is 75%), and did not a5ect the activity of thecatalyst much, coke may cover part of the surface of catalyst.

3.6. Stability

The stability of the catalyst with time-on-stream was ex-amined in the middle temperature range at 550◦C for 66 h.Before the experiment, the catalyst of NiC2O4=Y2O3 wasmixed with water and glycerol to form pellets of 0.5–1 mmand then decomposed in nitrogen at 500◦C for 2 h. Therelationships of selectivity of each product, conversion ofethanol with time-on-stream were shown in Fig. 7. Underthe experimental conditions, the conversion of ethanol was100%. The selectivity of hydrogen obviously increased

30 35 40 45 50 55 60 650

10

20

30

40

50

60

70

80

90

100

SCO

SCO2

SCH4

SH2

CETOH

C(m

ol%

),S

(mol

%)

Time (h)

Fig. 7. Conversion of ethanol, and selectivity of hydrogen asfunction of time-on-stream, obtained over the Ni=Y2O3 catalyst.Experimental conditions: mass of catalyst 10 g, particle size 0.5–1 mm; H2O=EtOHmol ratio 3:1, Pow rate 0:4 cm3 min−1(W=F=1500 g s cm−3); T = 550◦C; P = 1 atm.

J. Sun et al. / International Journal of Hydrogen Energy 29 (2004) 1075–1081 1081

during the Arst 59 h from 49.6% to 61.4% and decreasedduring the last 7 h from 61.4% to 53.8%. And, if the stabilityof the catalyst was tested at a lower temperature, longer timeof stability will be found.

4. Conclusion

To sum up, the present results clarify that the novelNi=Y2O3 catalyst produced hydrogen-rich gas mixture inlow and middle temperature range, possessed high activity,and good stability for steam reforming of ethanol to hydro-gen production. The catalyst of Ni=Y2O3 is a good choiceto be used in ethanol steam reforming processors for fuelcell applications.

Acknowledgements

The funding provided for this work by 973 Project(2002CB211800) of China, the help in directions of Prof.C.M. Hong, the cooperation of Ms. X.L. Liu in XRD mea-surements and the technical assistance of Dr. J.T. Ma inBET measurements are gratefully acknowledged.

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