ELECTROCHEMISTRY OF GAS-PHASE SPECIES AT A SOLID-STATE CELL CONTAINING VANADYL SULFATE POWDER AS THE ELECTROLYTE

In the absence of a sol uti on phase wi th an argon atmosphere, vanady l sulphate tri hydrate can be oxidized to V(V) and reduced to V(III) a t a carbon electrode. Replacing the argon with dioxygen does not alter the electrochemistry of V(IV); however, the reduction of dioxygen occ urs. Evidence that this process proceeds both by direct electrolysis a t the carbon electrode and through mediation by V(III) is provided. Wh en sulphur dioxide is the component in the gas phase, only the direct oxidation at a-carbon electrode is observed. Switching between oxygen or sulphur dioxide and argon in a flow cell demonstrates steady-state amperometric response to these gases on the time scale of 30 seconds.