Speciation analysis of aqueous polyselenide solutions
- Clark Univ., Worcester, MA (United States). Dept. of Chemistry
Selenide and polyselenide UV-vis absorption spectroscopic characteristics were investigated for aqueous polyselenide solutions. From these observations equilibria interrelationships between OH{sup {minus}}, H{sup +}, H{sub 2}Se, HSe{sup {minus}}, Se{sup {minus}2}, Se{sub 2}{sup {minus}2}, Se{sub 3}{sup {minus}2}, and Se{sub 4}{sup {minus}2} were probed. The standard cell potential for the reduction of 1/2 Se{sub 2}{sup {minus}2} to Se{sup {minus}2} was determined to be {minus}0.716 V. The equilibrium reactions of Se{sub 3}{sup {minus}2} and 2 Se{sub 4}{sup {minus}2} with Se{sup {minus}2} to 3 Se{sub 3}{sup {minus}2}, respectively, have pK{sub 23} = {minus}0.7 ({+-}0.1) and pK{sub 34} = {minus}4.0 ({+-}0.1) in 0.5 to 3M aqueous electrolytes. Consistent with these equilibria, the free energy of formation for Se{sub 2}{sup {minus}2}, Se{sub 3}{sup {minus}2}, and Se{sub 4}{sup {minus}2} have been determined as 121, 115, nd 121 kJ/mol, respectively. Polarization studies of these polyselenide solutions demonstrated Pt and CoSe as efficient catalytic surfaces for the oxidation and reduction of selenide species.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 63196
- Journal Information:
- Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Journal Issue: 5 Vol. 142; ISSN 0013-4651; ISSN JESOAN
- Country of Publication:
- United States
- Language:
- English
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