An Iron-Based High-Entropy Alloy with Highly Efficient Degradation for p-Nitrophenol

High-entropy alloys (HEAs) have attracted widespread attention due to their excellent mechanical properties. However, their functional properties arising from the supersaturated solid solution state can be improved. Advanced oxidation processes (AOPs) are considered to be an effective method for decomposing organic pollutants, and HEAs are proposed as effective candidates for AOP catalysts. Currently, several HEAs used for organic pollutant degradation are prepared through mechanical alloying. In this work, FeAlCoNi and FeAlCoNiB Fenton-like catalysts were prepared by single roll melt spinning and subsequent ball milling techniques. We found that the FeAlCoNiB HEA exhibits highly efficient degradation for p-nitrophenol (p-NP). The degradation efficiency of FeAlCoNiB is 120 times higher than that of FeAlCoNi, which confirms that boron functions effectively during the degradation process. FeAlCoNiB has a better degradation efficiency than pure iron powder and a degradation efficiency comparable to that of the amorphous Fe78Si11B11 alloy. Additionally, the degradation efficiency of FeAlCoNiBX increases (k values from 0.13 to 0.55 min−1) when the boron content increases from an X value of 0.25 to 1.25. We speculate that Fe2B favors the degradation process and promotes zero-valent iron to decompose organic pollutants through a galvanic cell effect. Possible p-NP degradation pathways are proposed after LC–MS analysis. This study provides a new series of HEA Fenton-like catalysts, which have the potential to be prepared into bulk devices for industrial applications.