Synthesis and Electrochemical Behavior of Two Microporous Polyoxomolybdates

Abstract:

Two new microporous polyoxomolybdates of (NH4)2[γ-Mo8O26] (Compound I) and (NH4)2[Mo4O13] (Compound II) were synthesized hydrothermally and characterized by elemental analysis, infra-red, TG analysis and single-crystal X-ray diffraction. In the synthesis process, we found that both organic template and transition metal salt play crucial roles in the formation of crystals. Cyclic voltammetry was used to study their electrochemical properties. The results reveal that the two compounds possess electrochemical activity in 0.2M H2SO4+Na2SO4 ( pH=1 ) solution and three multi-electron transferred redox reaction (I-I´, II-II´ and III-III´) processes were obtained. The first two redox reactions (I-I´, II-II´) are reversible reaction processes but another one (III-III´) is not. The electrochemical properties of the two compounds indicate their great potential applications in electroanalysis and electrocatalysis.

• Periodical: Advanced Materials Research (Volumes 79-82)
• Pages: 1479-1482
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.79-82.1479
• Online since: August 2009
• Authors: Qi Bao, Shu Fang Zhang, Dun Zhang
• Keywords: Crystal Structure, Electrochenmical Behaviour, Hydrothermally Synthesized, Supramolecular Compound

References

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[4] 0. 25 g (NH4)6Mo7O24•4H2O was dissolved into 5 mL water and 0. 2 mL HN(CH2CH2NH2)2 was dropped into this solusion. The mixture was stirred for 1 h , the pH of which was changed to 8. 0, sealed in a 25 mL Teflon-lined autoclave, and then heated for 120 h at 170 ℃. After the mixture was cooled to room temperature naturally, translucent block crystals was isolated in 82 % yield (based on Mo). Anal. Calc. ( H8 Mo4 N2 O13 ): H, 0. 18; N, 4. 43% Found: ( H, 0. 16; N, 4. 51%). A mixture of (NH4)6Mo7O24•4H2O (0. 247g), (CH3COO)2Zn (0. 183g), HN(CH2CH2NH2)2 (0. 2 mL) and water (10 mL), the pH of which was adjusted to 8. 0 by phosphate acid, was stirred for 4 h and then was sealed into a 25 mL autoclave. Keep the mixture at 150 ℃ for 5 d and cooled to room temperature. Translucent block crystals were yield in 61% (based on Mo). Anal. Calc. for Compound II ( N2H8Mo4O13 ): H，0. 18；N，5. 43% Found: ( H, 0. 16；N, 5. 53 ). IR ( KBr cm-1): 938(s), 894(s), 859(s) and 756(s) for v (Mo =Ot) or v (Mo-O-Mo), 3199(s) for v(N-H).

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