关键词: SrFe_0.6Co_0.4O₃催化剂, 孔雀石绿, 催化, 降解, 反应机理, 电荷转移

Abstract: Malachite green (MG) is a triphenylmethane dye with a complex molecular structure, which is difficult to be degraded, and it makes a difficulty in industrial wastewater treatment. In this paper,based on Goldschmidt radius tolerance rule, the ABO₃ type catalysts with formula SrFe_(1-x)Co_xO₃ (x=0～1) for degrading MG was designed. After experimental investigation, the SrFe_0.6Co_0.4O₃ with highest catalytic activity was selected as target catalyst for MG degradation. The characteristics of this catalyst were analysed by XRD, SEM, BET and XPS methods. XRD pattern shows that the catalyst is pure perovskite crystal; the SEM image shows the morphology of catalyst particles is “honeycomb” flake with irregular stacking. In the BET adsorption isotherm of the catalyst, there is no obvious hysteresis loop, which means that there is no pore like “ink bottle”. Seeing from the XPS spectrum of the catalyst, the B-position has four ions (Fe²⁺/Fe³⁺ and Co²⁺/Co³⁺) at the same time, and the distribution ratio of above four ions vary greatly before and after the catalytic reaction. Based on these results, the mechanism of the catalytic reaction is speculated as follow: at first the Co³⁺ on B-site with the dissolved oxygen to form active oxygen [O₂]⁺ and Co²⁺; then the [O₂]⁺ oxidizes the MG, as well as the positive charge of [O₂]⁺ is transferred to the Fe²⁺ on B-site to form Fe³⁺; at last, the positive charge of Fe³⁺ could be transferred to Co²⁺ on the B-site to form Co³⁺, and the transfer and circulation of the charge in catalytic process is completed.

Key words: SrFe_0.6Co_0.4O₃ catalyst, malachite green, catalysis, degradation, reaction mechanism, charge transfer