Broad-spectrum photothermal high-entropy alloy powders for efficient solar-driven antibacterial and dye degradation

The development of solar-driven photothermal materials for efficient wastewater treatment remains a significant challenge. Herein, we have designed and synthesized a series of FeMnCo-based high-entropy alloy powders (HEAPs) with exceptional photothermal conversion, antibacterial properties and dye degradation capabilities. Under visible light irradiation, FeMnCoTiV HEAPs demonstrate a solar absorption efficiency of 85.6% across a broad solar spectrum range (200-2500 nm). This broad absorption range enables HEAPs to heat water to 45 degrees C, and completely degrade Orange II within 15 minutes. Furthermore, HEAPs effectively inhibit the growth of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Theoretical calculations of the d-band density of states (d-DOS) attribute the wide absorption range and high efficiency to the optimized distribution of 3d electrons, particularly influenced by the high proportion of Ti and V states in the alloy. The distribution which correlated with d-d interband transitions indicated that the solar absorption properties could be controlled by adjusting elemental composition. These findings not only open additional pathways for wastewater treatment but also provide insights for the composition design and industrial applications of HEAPs.