Study on Performance and Mechanism of the Ball-Milling-Driven Piezoelectrochemical Effect on Catalytic Oxidation of Toluene in the Air Condition

We use the characteristics of piezoelectric barium strontium sulfate (BSS) to collect the mechanical energy generated byball-milling to produce the piezoelectrochemical effect. At the same time,in coordination with the mechanochemical effect generated by ball-milling, toluene is oxidized to phenol in air atmosphere. Starting withcharacterization, BSS was characterized by X-ray powder diffraction(XRD), thermalfield emission scanning electron microscopy, electro-chemical test, Fourier transform infrared spectroscopy, and ultravioletvisible spectroscopy. Moreover, six reaction parameters???catalyst type,catalyst dosage, reaction time, ball-milling speed, pH value of reactionsolution, and toluene concentration???were discussed, and the optimumreaction conditions were obtained. Ultimately, the mechanism ofcatalytic reaction was discussed. It is found that the superoxide radical(center dot O2-), which formed by oxygen in the air and electrons generated by theBSS piezoelectric effect, is the main oxidation species for the oxidation of toluene. The oxidation potential of center dot O2-is-0.33 V versusNHE, which can oxidize toluene to phenol without excessive oxidation