Composition engineering of high-entropy diboride nanoparticles for efficient catalytic degradation of antibiotics

Exploiting functional characteristics of high-entropy boride materials is critical for extending their potential applications in harsh environments. Herein we develop high-entropy diboride (HEB2) nanoparticles with efficient catalytic performance by engineering their compositions. Based on the theoretical analysis of the lattice size difference and mixing enthalpy of HEB2and the self-propagating combustion mode of the system, six different compositional HEB2nanoparticles are synthesized viaa facile, rapid, and low-cost combustion synthesis method. By engineering their compositions, we achieve the efficient catalytic ability of HEB2nanoparticles in persulfate activation towards antibiotics removal, namely the highest tetracycline removal efficiency of 93.5%. Further investigations of the adsorption energy and the charge density difference of various adsorption sites viadensity functional theory confirm that the outstanding catalytic ability mainly originates from the Ti constituent rather than the high-entropy effect. In addition, a potential catalytic mechanism of HEB2towards persulfate activation for antibiotics degradation is proposed based on the detected reactive oxygen species and the computational reaction energy barrier. This study not only provides theoretical basis for their component design in the efficient catalytic degradation of antibiotics, but also shows a promising application of HEB2for removal of emerging contaminants from environmental water matrices.