Enhancement and mechanism of nano-BaTiO3 piezocatalytic degradation of tricyclazole by co-loading Pt and RuO2

Abstract

Two electrocatalysts Pt and RuO₂ were directionally co-loaded on the nano-piezomaterial t-BaTiO₃ by a two-step process: the alkali deposition–oxidation of RuO₂ followed by the selective photo-reduction deposition of Pt. It was found that both Pt and RuO₂ could considerably improve the piezo-degradation efficiency of t-BaTiO₃ for pollutants. For the biorefractory pesticide tricyclazole, RuO₂/t-BaTiO₃/Pt possessed a piezo-degradation kinetic constant of 0.032 min⁻¹. The rate constant was 3.11, 2.56 and 2.58 times that of t-BaTiO₃, Pt/t-BaTiO₃ and RuO₂/t-BaTiO₃, respectively. Moreover, the rate constant of RuO₂/t-BaTiO₃/Pt was greater than the sum (0.025 min⁻¹) of the rate constants of two single-loaded materials, Pt/t-BaTiO₃ and RuO₂/t-BaTiO₃. This indicates that co-loaded Pt and RuO₂ in RuO₂/t-BaTiO₃/Pt have a synergistic enhancement effect on the piezo-degradation. By analyzing the kind and amount of the reactive oxygen species (˙OH, ¹O₂, ˙O₂⁻ and H₂O₂) from these nano-piezocatalytic systems, it was inferred that Pt acted as a cathodic- and anodic-like catalyst while RuO₂ acted as an anodic-like catalyst. The mechanism of the synergistic catalysis for co-loaded Pt and RuO₂ was similar to the principle of an electrolytic reactor, in which Pt and RuO₂ were its two catalytic nano-electrodes and the power was from the piezo-potential of t-BaTiO₃.