Spatial construction of Pd and MnOx on a facet-engineered BiVO4 photocatalyst for efficient removal of glyphosate pesticide

Abstract

As a widely used organophosphorus pesticide, glyphosate in aquatic environments and soil is causing increasing risks to public health and the environment, and feasible solutions to eliminate glyphosate contaminants are still in demand. Herein, we report on the photocatalytic removal of glyphosate using a decahedron bismuth vanadate (BiVO₄) photocatalyst by incorporating Pd and MnO_x cocatalysts on different exposed facets. It is elucidated that the selective deposition of Pd on the electron-accumulating {010} facets of BiVO₄ substantially enhances the oxygen reduction reaction, thereby accelerating the formation of ˙O₂⁻ radicals. Concurrently, the construction of MnO_x on the hole-accumulating {110} facets promotes the water oxidation reaction, augmenting the production of ˙OH radicals. The synergistic integration of Pd and MnO_x dual cocatalysts onto different facets of BiVO₄ results in a striking enhancement in glyphosate degradation rates, surpassing those of pristine BiVO₄ by two orders of magnitude. Furthermore, the optimized BiVO₄ was assembled on cellulose fabric and shows effective degradation capability in glyphosate-polluted soil. This study underscores the significance of rationally designing semiconductor photocatalysts at the nano-/micrometer scale for application in the removal of persistent environmental contaminants.