Abstract
Herein are reported the first results and the discussion about the oxidation of the highly stable aqueous solution of sodium dodecahydro-closo-dodecaborate Na2B12H12, a potential anodic fuel for energy conversion devices (fuel cells). The anion B12H12− is indeed chemically stable: it has an excellent stability over 3 weeks in both alkaline and acidic media; and heterogeneous hydrolysis does not take place as evidenced by differential electrochemical mass spectrometry (DEMS) measurements (using a gold electrode). According to the cyclic voltammetry experiments, the B12H122− anion can be oxidized over bulk electrodes made of platinum, gold or silver, the oxidation taking place at low potential values with platinum and high potential values with gold and silver electrodes. The overall reaction is complex and generates various products, which were analyzed over 1000 cycles of voltammetry in the range −1.05 and 0.6 V vs. SCE. These products are mainly composed of B7- and B11-based polyboranes, which is indicative of a partial oxidative degradation of B12H12−. To sum up, the present article demonstrates the potential of the aqueous solution of sodium dodecahydro-closo-dodecaborate Na2B12H12 as anodic fuel, but it also stresses on the necessity of further works especially focusing on multimetallic electrodes (electrocatalysts) that could quantitatively and completely valorize this fuel.