Utilizing the enhanced Fenton-like catalytic reactivity and superior photothermal conversion capacity of cobalt doped nickel phosphide for efficient peroxymonosulfate activation and antibiotics degradation

Abstract

This study developed a novel photothermal peroxymonosulfate (PMS) activation method for degrading antibiotic pollutants. A bifunctional photothermal catalyst, Co-Ni2P, was synthesized, combining superior light-to-heat conversion capability and enhanced Fenton-like catalytic activity. This catalyst was used to construct a Fenton-like system driven by near-infrared (NIR) irradiation (Co-Ni2P+PMS+NIR). The degradation rate of this designed system was approximately 3.5 times and 11.1 times to that of Ni2P+PMS+NIR system and Co-Ni2P+PMS+Dark system, respectively. These results demonstrated the important role of cobalt doping and NIR irradiation in the PMS activation and antibiotic degradation. The cobalt doping introduced additional reactive sites and bimetallic synergistic effect, while NIR was effectively converted into heat by Co-Ni2P to elevate the reaction temperature, which collectively improved the degradation efficiency of Co-Ni2P+PMS+NIR system. Radical (SO4·-) and nonradical (1O2 and electron transfer process) pathways were identified to jointly mediate the oxidation of antibiotic pollutant represented by levofloxacin. Furthermore, NIR showed stronger penetration capacity and less energy loss, thus was more suitable for photothermal degradation system applied in deep water with turbidity and colority. This work provided new insights into the construction of NIR-driven photothermal Fenton-like systems for efficient water purification.