The Standard Formation Enthalpies of Spherical ZnO Nano-Particles: Size Matters

Article Preview

Abstract:

Four kinds of spherical nanoZnO particles with diameter of 20 nm, 30 nm, 40 nm and 50 nm were characterized by XRD and SEM. Based on a thermodynamic cycle, the standard molar formation enthalpies (ΔfHm) were measured and calculated by the RD496-2000 micro-calorimeter. They are (-328.41±1.575) kJ·mol–1 (50 nm), (-323.11 ± 1.579) kJ·mol–1 (40 nm), (-313.47 ± 1.581) kJ·mol–1 (30 nm), (-307.66 ±1.616) kJ·mol–1 (20 nm). The results show that nanosized ZnO has higher standard molar formation enthalpy compared to that of bulk ZnO (–350.46 ± 0.27 kJ·mol–1), indicating that the stability of nanosized ZnO decreases. More interestingly, the results show that the smaller size of the ZnO nanoparticles, the higher standard molar formation enthalpy was obtained. This indicates that ZnO nanoparticles get destabilized when the size decreases. The value of the standard molar formation enthalpies y (kJ·mol–1) and size x (nm) can be approximately described by a linear function of y = –0.7189 x –293.

You might also be interested in these eBooks

Info:

Periodical:

Pages:

62-66

Citation:

Online since:

July 2015

Export:

Price:

Permissions CCC:

Permissions PLS:

Сopyright:

© 2015 Trans Tech Publications Ltd. All Rights Reserved

Share:

Citation:

* - Corresponding Author

[1] T.L. Hill. Nano Letters 1 (2001) 159-160.

Google Scholar

[2] A. Kathalingam, S. Valanarasu, V. Senthilkumar and J.K. Rhee. Materials Chemistry and Physics 38 (2013) 262-269.

Google Scholar

[3] J.Y. Jiang, Z.Y. Huang, Y. Mi, Y.F. Li and A.Q. Yuan. Progress in Chemistry 22 (2010) 1058-1067.

Google Scholar

[4] Y.L. Chen, C.E. Zhang, C. Deng, P. Fei, M. Zhong and B.T. Su. Chinese Chemical Letters 24 (2013) 518-520.

Google Scholar

[5] J. Leitner, M. Kamradek and D. Sedmidubsky. Thermochimica Acta 572(2013) 1-5.

Google Scholar

[6] Y.H. Zhang, S.C. Zhang and X.G. Li. Chinese Journal of Inorganic Chemistry 19 (2003) 41-44.

Google Scholar

[7] G.C. Fan, Z.Y. Huang, Y.J. Ma, Jiang, J. Y.; Li, Y. F.; Tan and X. C. Science China Chemistry 41 (2011) 1477-1481.

Google Scholar

[8] G.C. Fan, Z.Y. Huang, J.Y. Jiang, Y.F. Li and L. Sun. Chemical Journal of Chinese Universities 05 (2011) 1016-1018.

Google Scholar

[9] M.P. Lu, J.H. Song, M.Y. Lu, M.T. Chen, Y.F. Gao, L.J. Chen and Z.L. Wang. Nano Letters 9 (2009) 1223-1227.

Google Scholar

[10] Q.Y. Xu, S.Q. Zhou and H. Schmid. Journal of Alloys and Compounds 487 (2009) 665-667.

Google Scholar

[11] G.C. Fan, J. Chen, Z.Y. Huang, J.Y. Jiang and Y.F. Li. Chinese Journal of Inorganic Chemistry 8 (2011) 1513-1516.

Google Scholar

[12] C.S. Qi, W. Li, X.M. Wu, L. Xu and D.C. Feng. Chinese Chemical Letters 18 (2007) 1159-1162.

Google Scholar

[13] X.M. Wu, Y. Li, S.S. Qu, D.S. Zhang, P. Liu and C.Y. Wang, Acta Phys. -Chim. Sin. 17 (2001) 956-960 (In Chinese).

Google Scholar

[14] R.Z. Hu, Y.J. Liang and Z.Q. Yang. Chemical Engineering, 04 (1987) 74-75 (In Chinese).

Google Scholar

[15] J.D. Cox, D.D. Wagman and V.A. Medvedev. CODATA Key Values for Thermodynamics, Hemisphere Publishing Corp, New York, (1989).

Google Scholar