Tribocatalysis and self-Fenton reaction of schorl/pyrite mineral composites under stirring conditions

Abstract

Tribocatalysis utilizes the energy generated from friction to activate chemical reactions, enabling the degradation of dyes and other pollutants. However, pyrite suffers from low electron-hole separation efficiency, which limits its catalytic performance. To address this challenge, we synthesized Schorl/Pyrite (SP) composite, leveraging schorl's self-polarization electric field to modulate pyrite's energy band structure and improve its charge separation efficiency. Herein, we systematically investigated the tribocatalytic performance of the SP composite. Under stirring conditions, the SP composite achieved a remarkable 93.8 % degradation of methylene blue (MB) within 12 h, significantly outperforming the individual components, schorl and pyrite, which degraded 47.5 % and 22.7 %, respectively. Additionally, the SP composites significantly increase the production of reactive oxygen species (ROS), with •O₂⁻ and •OH concentrations 406.27 % and 143.59 % higher than those of pure pyrite. The primary ROS, particularly hydroxyl radicals (•OH), were mainly produced through a self-Fenton reaction facilitated by tribocatalysis. Furthermore, a possible degradation pathway for MB during the tribocatalytic process was proposed. These results highlight the critical role of schorl's self-polarization in enhancing electron mobility and boosting tribocatalytic efficiency. These findings offer valuable insights into the tribocatalytic behavior of natural minerals, significantly improving their degradation efficiency. Additionally, the study introduces a novel approach to modulating the energy band structure of tribocatalytic materials, thereby optimizing their tribocatalytic performance.