Boosting PMS activation over BiVO4 piezo-photocatalyst to rapidly degrade tetracycline: Intermediates and mechanism

The photocatalytic activation of peroxymonosulfate (PMS) remained inefficient due to the rapid recombination of photoinduced carriers. Herein, monoclinic scheelite bismuth vanadate (m-BVO) piezo-photocatalyst was developed to improve the separation of photoinduced carriers and consequently promoted the photocatalytic activation of PMS. The piezoelectric effect of m-BVO was analyzed by piezo-response force microscopy (PFM). Better still, m-BVO with the piezoelectric effect exhibited improved photocatalytic activities to tetracycline (TC) elimination with the assistance of PMS. Compared to t-BVO without the piezoelectric effect, the TC degradation kinetic rate of m-BVO with the piezoelectric effect increased by 1.1 times. The notable enhancement contributed to the internal electric field of m-BVO, which drove the photoinduced electrons and holes separation to the contrary surfaces of m-BVO and hence promoted PMS activation and TC degradation. Furthermore, the possible mechanism of piezo-photocatalytic activation of PMS for TC degradation was revealed through a comparative experiment. The toxicities of the intermediate products, degradation pathways in the PMS system, and antibacterial experiments were also analyzed. In summary, this work would shed more light on developing a piezo-photocatalyst to promote PMS activation.