Rapid reductive degradation of azo dyes by a unique structure of amorphous alloys

An Fe-based amorphous alloy was found to significantly enhance the reductive degradation of an azo dye in aqueous solution. The surface-area normalized rate constant was up to 2.0 L m(-2) min(-1) at room temperature, an order of magnitude larger than any previously reported value. The activation energy of the degradation process was calculated according to the Arrhenius equation, and a much lower value than those previously reported was obtained. Valence band measurement indicated that a depressed valence band maximum and a widened empty band were established in the amorphous ribbon. The unique structure of the amorphous alloy is important - it may reduce the activation energy of the degradation process and enhance the activity of the electrons, thus accelerating the degradation process.