The catalytic activity of the ceramic superconductor YBa2Cu3O7 − δ

The superconductivity of the ceramic solid YBa₂Cu₃O_{7 ? δ}, prepared by heating Y₂O₃, BaCO₃ and CuO at 920°C for 22 h, was checked by the Meissner effect. Chemical analysis established the formula of the compound prepared. A thermostated aqueous suspension of the superconductor, treated with a solution of H₂O₂, produced oxygen, whose volume was measured at intervals in a gas burette. From the initial rates of the first-order reaction at different temperatures, the activation enthalpy and entropy were 16 kJ mol^?1 and ?210 J K^?1 mol^?1 respectively. The rates of gas evolution were similar to those obtained when a MnO₂ sample was used as a catalyst. Neither the superconductor nor its semiconductor phase photocatalysed the decomposition of KMnO₄ solution. Evidence of the catalysed decomposition of N₂H⁺₅ by the superconductor is presented.