Fluorine-doped BiVO4 photocatalyst: Preferential cleavage of C-N bond for green degradation of glyphosate.

ABSTRACT

With increasing concerns on the environment and human health, the degradation of glyphosate through the formation of less toxic intermediates is of great importance. Among the developed methods for the degradation of glyphosate, photodegradation is a clean and efficient strategy. In this work, we report a new photocatalyst by doping F ion on BiVO4 that can efficiently degrade glyphosate and reduce the toxic emissions of aminomethylphosphonic acid (AMPA) through the selective (P)-C-N cleavage in comparison of BiVO4 catalyst. The results demonstrate that the best suppression of AMPA formation was achieved by the catalyst of 0.3F@BiVO4 at pH = 9 (AMPA formation below 10%). In situ attenuated total reflectance Fourier transforms infrared (ATR-FTIR) spectroscopy indicates that the adsorption sites of glyphosate on BiVO4 and 0.3F@BiVO4 are altered due to the difference in electrostatic interactions. Such an absorption alteration leads to the preferential cleavage of the C-N bond on the N-C-P skeleton, thereby inhibiting the formation of toxic AMPA. These results improve our understanding of the photodegradation process of glyphosate catalyzed by BiVO4-based catalysts and pave a safe way for abiotic degradation of glyphosate.