Hydrogen generation by reaction of Al–M (M = Fe,Co,Ni) with water

Energy 113 (2016) 282e287

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Hydrogen generation by reaction of AleM (M ¼ Fe,Co,Ni) with water J. Liang a, L.J. Gao a, N.N. Miao b, Y.J. Chai a, *, N. Wang b, **, X.Q. Song a a b

School of Chemistry and Materials Science, Hebei Normal University, Hebei, Shijiazhuang 050024, China Analysis and Testing Centre, Hebei Normal University, Hebei, Shijiazhuang 050024, China

a r t i c l e i n f o

a b s t r a c t

Article history: Received 20 November 2015 Received in revised form 3 July 2016 Accepted 4 July 2016

The addition of Fe, Co and Ni to Al significantly improves the production of hydrogen in AleH2O reaction. The total mass of Fe and Ni is less than the mass of Co. However, the hydrogen evolution induced by Co reaches ~1000 ml g1 and the induction time shortens to 1.4 h at 35  C. After the initial induced reaction, Al rapidly reacts with water even at 25  C and the yield reached 90.0%. The additional Fe, Co and Ni combined with Al forms the galvanic cell and induce AleH2O reaction. The Al(OH)n hydrate formed in the reaction accelerates the removal of alumina and the reaction rate of AleH2O reaction, along with a decrease in the corrosion potential and an increase in the corrosion current. Beside that, both the pH and released heat in the local domain favor the AleH2O reaction. © 2016 Elsevier Ltd. All rights reserved.

Keywords: Hydrogen generation Hydrolysis reaction Aluminum

1. Introduction Hydrogen energy as one of the clean energies has been attracted much attention, especially; hydrogen is used as the energy source in portable applications where it reacts with oxygen to produce electricity. Several methods have been used to generate hydrogen [1,2], such as in hydrocarbon fuel, water electrolysis and metal hydride. However, these methods do not satisfy the requirements of practical application completely. Therefore, the sustainable, simple and inexpensive hydrogen generation method should be developed. Most of the hydrogen in the earth remains in water; hence the reaction of Al with water can be utilized to continually supply a high amount of pure hydrogen in an inexpensive and simple manner [3e5]. However, this method suffers from the spontaneous formation of an inert, dense and stable alumina film on the Al surface, thus hindering AleH2O reaction. This problem can be efficiently solved by breaking this film by ball milling Al metal [6e8], increasing the temperature and varying the pH [9] and composition of the solution [10]. The particle size of Al and other metal decreases by ball milling, thus increasing the reaction surface area and various defects and accelerating the AleH2O reaction. The

* Corresponding author. ** Corresponding author. E-mail addresses: [email protected] (N. Wang).

AleH2O reaction is exothermic, thus spontaneously proceeds at a certain rate. Moreover, when the initial test temperature is set to 70  C, the oxide film is easily destroyed and the Al rapidly reacts with water [11]. Al is oxidized to form Al(OH) 4 at a high alkali concentration (pH > 12) and, it becomes Al3þ at a less acidic medium. The addition of salts (NaCl, MgCl2, NiCl2, CoCl2, and FeCl3) partially favors AleH2O reaction by pitting or forming the microgalvanic cell [10,12,13]. Undoubtedly, the mixing of Al with Ga, Bi, In, Sn, Li, Mg and Ca by ball milling effectively breaks the alumina film and promotes the corrosion of Al because of the formation of a microgalvanic cell or the production of a soluble hydroxide [7,14e16]. However, these small particles are easily oxidized in the air and lose the reaction activity. Recently, the hand-mixing of Al and TiO2 followed by immersing the mixture in an Al(OH)3 solution has also been effective in increase the production of hydrogen [16,17]. Previously, we reported that the mixing of Al and FeeB using a mortar for less than 5 min significantly accelerated the corrosion of Al and hydrogen evolution [18]. However, it was inevitable for these particles to agglomerate in the air. In this study, the commercial Fe, Co and Ni without any treatment was directly used as the catalyst, meanwhile, the effect of these metals on AleH2O reaction was investigated.

2. Experimental (Y.J.

http://dx.doi.org/10.1016/j.energy.2016.07.013 0360-5442/© 2016 Elsevier Ltd. All rights reserved.

Chai),

[email protected]

The commercial Co, Fe and Ni (analytical reagent, 99.9%)

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purchased from Sinopharm Chemical Reagent Co. Ltd was directly used as the raw material without any treatment. The different mass of Co, Fe and Ni were manually mixed with 0.2 g Al (Tianjin Damao Chemical Reagent Factory, 99.0% purity) for < 5 min. The mixture was rapidly transferred into the deionized water (30 mL, pH ¼ 6.7e6.8) in a sealed 50 mL flask under stirring. The initial reaction of the mixture was allowed to proceed for 400 min, and then consecutive batches of pristine 0.2 g Al were added to the same flask individually in succession. The flask was heated on a water bath to maintain a constant temperature during the entire reaction, as shown in Fig. 1. The hydrogen produced was collected in an inverted burette completely filled with tap water. The volume of hydrogen produced within 400 min was recorded at 10 min intervals from the change in the water level in the inverted burette. Each reaction repeated more than three times to get the parallel data. The Tafel curves of Al in Al(OH)3 solution were recorded using a CHI 660E electrochemical workstation. A mixture of 0.2 g Al, acetylene black and polyvinylidene fluoride (PVDF) in a weight ratio of 9:0.5:0.5 was dispersed in N-methylpyrrolidinone (NMP). The slurry was cast on a polished nickel plate (1  2 cm2). The test was carried out using this electrode as the working electrode, a Pt working electrode as the counter work electrode, and a saturated calomel electrode (SCE) as the reference electrode. The measurements ranged from 1 V to 1 V at 0.01 mV s1. The structure of the byproduct was determined using a Bruker D 8 Advanced Xeray diffractometer (XRD) equipped with Cu Ka radiation at a voltage and current of 40 kV and 40 mA, respectively. The morphology of the products was investigated using an Se4800 fieldeemission scanning electron microscope (FEeSEM). 3. Results and discussion 3.1. Effects of Fe, Co and Ni contents on hydrogen generation Al almost does not react with water at low temperature (<50  C). When Fe, Co or Ni and 0.2 g Al were immersed in deionized water, the reaction rate and the production of hydrogen at 35  C increased as shown in Fig. 2 and Table 1. When the amount of Fe was increased from 0.01 to 0.07 g, the production of hydrogen reached ~875 ml g1 (x ¼ 0.02 g) and the induction time was ~2 h at 35  C. The hydrogen evolution induced by Co was ~970 mL g1 (x ¼ 0.2 g) and the induction time shortened to ~1.4 h. When 0.05 g of Ni was added, the production of hydrogen reached 1075 mL g1 (x ¼ 0.05 g) and the induction time was ~2.7 h. By comparing the effect of Fe, Co and Ni, it can be concluded that the induction time of

Fig. 2. Effect of Fe (a), Co (b) and Ni (c) on AleH2O reaction at 35  C, the inset plot is the effect of mass on the induction time.

Fig. 1. Scheme of the experimental apparatus. 1. Water bath, 2. Three-necked flask, 3. Silicon rubber tube, 4. Water container, 5. Inverted burette.

Ni-promoted reaction was longer; however, the yield was higher at 35  C. When the initial temperature was increased to 45  C (S1) as expected, the hydrogen generation rate of AleH2O reaction clearly increased for A and B. The maximum reaction rate for A increased

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Table 1 Parameter of Al-Fe(x ¼ 0.02 g), Al-Co(x ¼ 0.2 g) and Al-Ni (x ¼ 0.05 g) mixture at 35  C (a) and 45  C(b). Additive

Fe Co Ni

Induction time (min)

Hydrogen generation volume (mL g1)

Maximum hydrogen generation rate (mL g1 min1)

pH

a

b

a

b

a

b

a

b

116 86 160

33 80 69

875 972 1075

1222 1082 760

3 4 5

4 4 2

9.8 9.8 9.6

9.7 9.7 9.9

from ~3 mL g1 min1 at 35  C to 4 mL g1 min1 at 45  C. The induction time shortened to ~0.5 h for A (x ¼ 0.02 g) and ~1.3 h for B(x ¼ 0.2 g), respectively. The amount of hydrogen generated by Feand Co-induced AleH2O reaction was close to 1000 mL g1 and that by Ni-induced reaction was ~700 mL g1, indicating that the induced order of Fe, Co and Ni at 45  C was Co > Fe > Ni. 3.2. Consecutive addition of Al batches After the AleH2O reaction was induced by Fe, Co and Ni at 25  C, 35  C and 45  C, Al batches were consecutively added to the same flask. The maximum hydrogen production at 25  C induced by Co (x ¼ 0.2 g) increased from ~6.0 mL g1 min1 (1st) to 14.0 mL g1 min1 (3rd), as shown in Figs. 3 and S-2. Then, the reaction rate was maintained. The reaction rate at 25  C induced by Ni(x ¼ 0.05 g) was slightly lower than that induced by Co and Fe. The production of hydrogen induced by Ni was just close to~1000 mL g1 after the addition of five batches. Generally, no hydrogen was obtained in the AleH2O reaction at 25  C. However, this reaction at 25  C significantly was improved by the consecutive addition, especially for the Co-induced AleH2O reaction. It was reported that Al(OH)3 acted as a catalyst and promoted the removal of alumina film and the corrosion of Al [16e18]. The freshly formed Al(OH)3 in the AleH2O reaction in this study smoothly afforded the hydrate of alumina oxide and then initiated the AleH2O reaction. With increasing the temperature, the maximum hydrogen production induced by Co dramatically increased from ~18 mL g1 min1 at 35  C to ~35.0 mL g1 min1 at 45  C. It increased from ~13 mL g1 min1 at 35  C min1 to ~20.0 mL g1 min1 at 45  C for that induced by Ni and Fe. Herein, the induction time shortened and the amount of hydrogen rapidly reached the maximum, indicating the importance of testing temperature in AleH2O reaction. Moreover, the AleH2O reaction is exothermic, thus spontaneously accelerating this reaction at a certain interface. Although the rate of reaction increased with increasing temperature, the average pH value measured using a pH meter in the solution remained at 9e10. This indicates that OH ions in the solution originated the dissolution of Al(OH)3 (Al(OH)3 / Al3þ þ 3OH). Because the formed Al(OH)3 covered the Al surface, the accurate pH and the local heat at the interface of AleAl(OH)3 cannot be detected. The violent reaction indicates the concentration of OH ions and heat at the reaction interface is probably higher than the average pH. 3.3. Corrosion potential and current Fig. 4 shows the typical Tafel curves, corrosion potential and current. The corrosion potential of Al induced by Co decreased from 0.34 V to 0.58 V (vs.SCE) with increasing temperature from 25  C to 55  C, along with the increase in the corrosion density increase from 1.05 to 14.13 mA. Similarly, in the Feeinduced reaction, the initial potential was approximatedly 0.34 V, and it decreased to 0.45 V with increasing temperature. The potential of

Fig. 3. Yield and the maximum reaction rate for Al-Fe, Al-Co and Al-Ni mixture at 25  C (a), 35  C (b) and 45  C (c). A, B and C present the data induced by Fe, Co and Ni, respectively.

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that the Al corrosion induced by Co, Fe and Ni accelerates, consistent with hydrogen evolution.

3.4. Mechanism of AleH2O reaction The shapes of pristine Fe, Co and Ni were spherical (a), elliptical (b) and dendritic (c), respectively, as shown in Fig. 5. They adhered to the Al surface while mixing, forming microgalvanic cell in water (d) and gradually triggering the AleH2O reaction. These particles collected using their magnetic property during the AleH2O reaction agglomerated and adhered some Al(OH)n (S3). Moreover, a porous Al(OH)n hydrate formed (e) firstly on the Al surface and a bayerite Al(OH)3 (S4) precipitate (f) was finally was detected. Along with the hydrogen evolution, this reaction can be evaluated by the following processes, as shown in Fig. 6. The first step was to destroy the alumina film to ensure the progress of AleH2O reaction. The initial AleH2O reaction after adding the mixture (AleCo, AleFe, and AleNi) was slowly induced at 25e35  C using a galvanic cell, where Al acted as the anode and FeeCoeNi acted as the cathode. The Al was oxidized and formed Al(OH)n hydrate at special sites. Moreover, the alumina oxide film rapidly hydrated by combining with solid Al(OH)3 because of the thermodynamic instability [19]. After the hydration, the oxide film was rapidly destroyed and the Al was exposed to water, thus initiating the AleH2O reaction and decreasing the corrosion potential, increasing the corrosion current and generating hydrogen rapidly. Moreover, this reaction released heat and increased the temperature of water at local sites, thus propagating this reaction. Next, the Al was covered by the amorphous and porous cotton-like Al(OH)n hydrate layer that could transfer H2O and OH ions to the surface of inner Al [16,17]. A rapid Al corrosion occurred, producing hydrogen. With the progress of this reaction, the Al(OH)n hydrate became spikelike, and finally converted to the rod-like bayerite Al(OH)3. The rod-like Al(OH)3 could be easily broken, thus providing sufficient space or interface to transfer H2O or OH ions and facilitating the corrosion of Al. In the consecutive addition of Al batches, the Al was rapidly corroded without any induction time in this special alkaline environment containing fresh Al(OH)3 because of the rapid hydrate and alumina removal. Much of water was consumed after the consecutive addition of Al, where the Al reacted with H2O and Al(OH)3 acted as the catalyst. When water was added to the same reaction flask, the reaction behavior similar as that in the consecutive addition of Al batches kept on again.

4. Conclusion

Fig. 4. Typical Tefel curves (a), the corrosion potential (b) and the corrosion current (c) at different temperature.

Ni-induced reaction slightly decreased from 0.30 to 0.46 V and the corrosion current increased from 0.41 to 16.9 mA. Clearly, the corrosion potential decreased and the current increased, when the AleH2O reaction occurred. Although, these results do not completely show the corrosion process, they qualitatively illustrate

The effect of Fe, Co and Ni on AleH2O reaction was investigated. The mixture of Fe, Co and Ni composed with Al forms the galvanic cell and induces AleH2O reaction. The hydrogen evolution at 35  C induced by Co reached 970 mL g1 (x ¼ 0.2 g) and the induction time was shortened to ~1.4 h. The induction time induced by Fe and Co was ~2 h and 2.7 h, respectively. After the reaction proceeded, the formed Al(OH)n hydrate increased the alumina removal and the rate of AleH2O reaction. Herein, the corrosion potential rapidly decreased and the corrosion current increased. When Al was consecutively added to the same flask, the AleH2O reaction rapidly occurred without any induction time. Moreover, the hydrogen volume induced by Co (x ¼ 0.2 g) remained stable in the consecutive addition of Al batches at 25  C and the maximum hydrogen production reached 15.0 mL g1 min1. With the increase in the temperature, both the hydrogen evolution and the reaction rate improved. This can be attributed to the rapid formation of hydrate and removal of alumina at the special domains.

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Fig. 5. SEM images of Fe (a), Co (b), Ni (c), the typical M-Al (M¼Fe, Co and Ni) mixture (d), the hydrate (e) and Al(OH)3 byproduct (f).

Fig. 6. Schematic illustration of AleH2O reaction process.

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Acknowledgments This work was supported by Fund of Hebei Education Department (QN2015224) and Natural Science Foundation of Hebei (No.B2014205085). Appendix A. Supplementary data Supplementary data related to this article can be found at http:// dx.doi.org/10.1016/j.energy.2016.07.013. References [1] Wu C, Zhang HM, Yi BL. Recent advances in hydrogen generation with chemical methods. Prog Chem 2005;17(3):423e9. [2] Choi B, Panthi D, Nakoji M, Kabutomori T, Tsutsumi K, Tsutsumi A. Novel hydrogen production and power generation system using metal hydride. Int J Hydrogen Energy 2015;40(18):6197e206. [3] Liu YG, Wang XH, Liu HZ, Dong ZH, Li SQ, Ge HW, et al. Improved hydrogen generation from the hydrolysis of aluminum ball milled with hydride. Energy 2014;1:421e6. [4] Yang WJ, Zhang Y, Liu JZ, Wang ZH, Zhou JH, Cen KF. Experimental researches on hydrogen generation by aluminum with adding lithium at high temperature. Energy 2015;15:451e7. [5] Zhao ZW, Chen XY, Hao MM. Hydrogen generation by splitting water with AlCa alloy. Energy 2011;5:2782e7. [6] Liu YG, Wang XH, Liu HZ, Dong ZH, Li SQ, Ge HW, et al. Effect of salts addition on the hydrogen generation of Al-LiH composites elaborated by ball milling. Energy 2015;89:907e13. [7] Fan MQ, Sun LX, Xu F. Feasibility study of hydrogen production for micro fuel cell from activated AleIn mixture in water. Energy 2010;35:1333e7.

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[8] Grosjean MH, Zidoune M, Huot JY, Roue L. Hydrogen generation via alcoholysis reaction using ball-milled Mg-based materials. Int J Hydrogen Energy 2006;21:1159e63. [9] Pyun S, Moon SM. Corrosion mechanism of pure aluminums in aqueous alkaline solution. J Solid State Electrochem 2000;4:267e72. [10] Chen XY, Zhao ZW, Liu XH, Hao MM, Chen AL, Tang ZY. Hydrogen generation by the hydrolysis reaction of ball-milled aluminum-lithium alloys. J Power Sources 2014;254:345e52. [11] Razavi-Tousi SS, Szpunar JA. Mechanism of corrosion of activated aluminum particles by hot water. Electrochim Acta 2014;127:95e105. [12] Figen AK, Coskuner B, Piskin S. Hydrogen generation from water Mg based material in various saline solutions (NiCl2, CoCl2, CuCl2, FeCl3, MnCl2). Int J Hydrogen Energy 2015;40(24):7483e9. [13] Macanas J, Soler L, Candela AM, Munoz M, Casado J. Hydrogen generation by aluminum corrosion in aqueous alkaline solution of inorganic promotes: the AlHidrox process. Energy 2011;36:2493e501. [14] Liu PP, Wu HW, Wu CL, Chen YG, Xu YM, Wang XL, et al. Microstructure characteristics and hydrolysis mechanism of Mg-Ca alloy hydride for hydrogen generation. Int. J Hydrogen Energy 2015;40(10):3806e12. [15] Huang XN, Gao T, Pan XL, Wei D, Lv CJ, Qin LS, et al. A review: feasibility of hydrogen generation from the reaction between aluminum and water for fuel cell applications. J Power Sources 2013;229:133e40. [16] Yang Y, Gai WZ, Deng ZY, Zhou JG. Hydrogen generation by the reaction of Al with water promoted by an ultrasonically prepared Al(OH)3 suspension. Int J Hydrogen Energy 2014;39(33):18734e42. [17] Teng HT, Lee TY, Chen YK, Wang HW, Cao GZ. Effect of Al(OH)3 on the hydrogen generation of aluminum-water system. J Power Sources 2012;219: 16e21. [18] Meng HX, Wang N, Dong YM, Jia ZL, Gao LJ, Chai YJ. Influence of MeB (M¼Fe, Co, Ni) on aluminum-water reaction. J Power Sources 2014;268:550e6. [19] Bunker BC, Nelson GC, Zavadil KR, Barbour JC, Wall FD, Sulliva JP, et al. Hydration of passive oxide films on aluminum. J Phys Chem B 2002;106: 4705e13.