PREPARATION OF Ni-Pt/La2O3 CATALYST AND ITS KINETICS STUDY OF HYDROUS HYDRAZINE FOR HYDROGEN GENERATION
Yujie ZHONG1,Hongbin DAI2(),Ping WANG2
1 Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China 2 Key Laboratory of Advanced Energy Storage Materials of Guangdong Province, School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641, China
Cite this article:
Yujie ZHONG,Hongbin DAI,Ping WANG. PREPARATION OF Ni-Pt/La2O3 CATALYST AND ITS KINETICS STUDY OF HYDROUS HYDRAZINE FOR HYDROGEN GENERATION. Acta Metall Sin, 2016, 52(4): 505-512.
Safe and efficient hydrogen storage remains a grand challenge in the widespread implementation of hydrogen fuel cell technology. Recently, chemical hydrogen storage has emerged as a promising alternative for vehicular and portable applications. A number of hydrogen-rich materials have been experimentally demonstrated to deliver large amounts of hydrogen under mild conditions with controllable kinetics. Among these materials of interest, hydrous hydrazine (N2H4H2O) is a promising but yet not fully explored candidate. The development of highly efficient catalyst and its reaction kinetics law are the key issues of N2H4H2O-based hydrogen generation (HG) systems. Herein, a supported Ni-Pt/La2O3 catalyst was prepared by a combination of co-precipitation and galvanic replacement methods. Via optimizing preparing processes, the developed catalyst enabled a complete decomposition of N2H4H2O to generate H2 at a reaction rate of 340 h-1 at 323 K, which outperforms most reported N2H4H2O decomposition catalysts. Phase/structural analyses by XRD, TEM and XPS were carried out to gain insight into the catalytic performance of the Ni-Pt/La2O3 catalyst. In addition, the effects of temperature, concentration of N2H4H2O and NaOH, and amount of catalyst on the N2H4H2O decomposition were investigated over the Ni-Pt/La2O3 catalyst. The kinetic rate equation may be represented by the expression: r = -d[N2H4H2O]/dt = 2435exp(-51.53/(RT))[N2H4H2O]0.3[NaOH]0(0.12)[Ni]1.03. The obtained results should lay the experimental and theoretical foundation for developing practical application of N2H4H2O-based HG system.
Fig.1 Schematic of preparation of Ni-Pt/La2O3 catalyst using a combination of co-precipitation and galvanic replacement methods
Fig.2 XRD spectra of Ni/La2O3, Ni90Pt10@Pt/La(OH)3 and Ni-Pt/La2O3 catalyst samples
Fig.3 TEM (a), HRTEM (b), HAADF-STEM (c) images of the Ni90Pt10/La2O3 (Pt∶Ni=1∶30) catalyst and corresponding EDS analysis result along the direction indicated by the black line in Fig.3c (d)
Fig.4 XPS results of Ni/La2O3, Pt/La2O3 and Ni90Pt10/La2O3 (Pt∶Ni=1∶30) catalysts
Method
Catalyst sample
Reaction rate h-1
H2 selectivity %
Co-precipitation
Ni/La2O3
6
72
Ni90Pt10/La2O3
200
96
Pt/La2O3
0
0
Co-precipitation/ replacement
Ni90Pt10@Pt/La(OH)3 (Pt : Ni=1 : 30)
185
94
Ni90Pt10/La2O3 (Pt : Ni=1 : 40)
222
99
Ni90Pt10/La2O3 (Pt : Ni=1 : 35)
280
100
Ni90Pt10/La2O3 (Pt : Ni=1 : 30)
340
100
Ni90Pt10/La2O3 (Pt : Ni=1 : 25)
340
100
Ni90Pt10/La2O3 (Pt : Ni=1 : 20)
340
100
Table 1 Comparison of catalytic performance between the catalysts using co-precipiation and co-precipiation/replacement methods
Fig.5 Effect of reaction temperature on N2H4H2O decomposition in the presence of Ni90Pt10/La2O3 (Pt∶Ni=1∶30) catalyst (a) and Arrhenius plot for determination of the apparent activation energy Ea (Ea=6.19×8.314=51.53 kJ/ mol) (b) (Y—molar ratio of N2+H2 and N2H4, r—catalytic reaction rate, T—catalytic reaction temperature)
Fig.6 Effect of N2H4H2O concentration on N2H4H2O decomposition in the presence of Ni90Pt10/La2O3 (Pt∶Ni=1∶30) catalyst (a) and a plot of lnr vs ln[N2H4H2O] ([N2H4H2O]: 0.1~0.9 mol/L) (b)
Fig.7 Effect of NaOH concentration on N2H4H2O decomposition in the presence of Ni90Pt10/La2O3 (Pt∶Ni=1∶30) catalyst (a) and a plot of lnr vs ln[NaOH] ([NaOH]: 0.05~0.3 mol/L) (b)
Fig.8 Effect of catalyst (Ni) amount on N2H4H2O decomposition in the presence of Ni90Pt10/La2O3 (Pt∶Ni=1∶30) catalyst (a) and a plot of lnr vs ln[Ni] ([Ni]: 0.1’0.3 mol/L) (b)
[1]
Wang P, Kang X D.Dalton Trans, 2008; 40: 5400
[2]
Zhu Q L, Xu Q.Energy Environ Sci, 2015; 8: 478
[3]
Demirci U B, Miele P.Energy Environ Sci, 2009; 2: 627
[4]
Cho S J, Lee J, Lee Y S, Kim D P.Catal Lett, 2006; 109: 3
[5]
Singh S K, Zhang X B, Xu Q.J Am Chem Soc, 2009; 131: 9894
[6]
He L, Huang Y Q, Wang A Q, Wang X D, Zhang T.AIChE J, 2013; 59: 4297
[7]
He L, Liang B L, Li L, Yang X F, Huang Y Q, Wang A Q, Wang X D, Zhang T.ACS Catal, 2015; 5: 1623
[8]
He L, Huang Y Q, Wang X D, Chen X W, Delgado J J, Zhang T.Angew Chem Int Ed, 2012; 51: 6191
[9]
Singh S K, Xu Q.J Am Chem Soc, 2009; 131: 18032
[10]
He L, Huang Y Q, Wang A Q, Lu Y, Liu X Y, Chen X W, Delgado J J, Wang X D, Zhang T.J Catal, 2013; 298: 1
[11]
Wen L, Du X Q, Su J, Luo W, Cai P, Cheng G Z.Dalton Trans, 2015; 13: 6212
[12]
Singh S K, Singh A K, Aranishi K, Xu Q.J Am Chem Soc, 2011; 133: 19638
SUN Li; SONG Qihong; HU Zhuangqi (State Key Laboratory of Rapidly Solidified Nonequilibrium Alloy; Institute of Metal Research; Chinese Academy of Sciences; Shengyang 110015)(Manuscript received 1995-05-10; in revised form 1995-09-05). STRUCTURE AND CATALYTIC PROPERTIES OF RAPIDLY SOLIDIFIED Cu_(30)Al_(70)ALLOY[J]. 金属学报, 1996, 32(1): 63-68.
[7]
SUN Li; SONG Qihong; HU Zhuangqi(Stale Key Laboratory of Rapidly Solidified Non-Equilibrium Alloys; Institute of Metal Research; Chinese Academy of Sciences;Shenyang 110015)(Manuscript received 1995-03-03; in revised form 1995-O5-05). FORMATION AND CATALYTIC ACTIVITY OF NANOCRYSTALLINE Cu_(30)Al_(70) ALLOY CATALYST[J]. 金属学报, 1995, 31(20): 341-345.