Performance and applications of ZnO/pyrolusite composite particle electrode.

In this research, we employed a synergistic three-dimensional (3D)-electrode technology in combination with a photocatalytic method to effectively treat wastewater containing chlorine derived from sulfonated phenolic resin (SMP). To modulate the band gap of single ZnO through semiconductor compounding, we successfully synthesized a ZnO/pyrolusite composite particle electrode on the surface of a pyrolusite particle electrode via a hydrothermal method. By incorporating MnO2 into pyrolusite, the ZnO band gap was modified, leading to a reduction in bandwidth of approximately 1.21 eV compared to pristine ZnO. Consequently, the light absorption range of the material was significantly broadened. Through the synergistic effect of photocatalysis, we achieved an impressive 96.45% removal rate of chemical oxygen demand (COD) in SMP wastewater, which effectively enhanced the photocatalytic performance of the material. Furthermore, our quenching experimental study confirmed the involvement of active chlorine species (ACl: Cl2, HClO, and ClO-), OH, h+, and O2- in the degradation process of SMP within the photocatalytic system constructed by the ZnO/pyrolusite composite particle electrode. The relative contributions were ranked as follows: ACl > h+ > ·OH > ·O2-.