A pentametallic high-entropy mixed-dimensional mesoporous heterostructure for azo-dye wastewater degradation and decolorization

Abstract

The degradation and decolorization of azo-dyes wastewater require more efficient methodologies to reduce this primary water pollution source. Herein, we developed a pentametallic (Au-Ti-Mg-Al-Cu) high-entropy mixed-dimensional mesoporous heterostructure (HEMDMHs) for azo-dye wastewater degradation and decolorization. This HEMDMHs structure was constructed by irregularly growing nanoscale Mg-Al-Cu layered-double-hydroxide (LDH) onto micro-scaled 2-dimensional (2D) Ti3C2Tx MXene and then in-situ synthesizing ultrasmall (<3 nm) 0-dimensional (0D) gold nanoclusters (AuNCs) onto the LDH/MXene mesoporous support. This Au-Ti-Mg-Al-Cu HEMDMHs can efficiently degrade azo-dyes wastewater within 2 min, producing colorless and clear solutions. This exceptional performance can be achieved across a wide pH range of 2 to 12 and temperatures ranging from 0 to 60 °C under sunlight. Furthermore, this HEMDMHs can be easily recoverable through centrifugation for reuse. Mechanistic investigation revealed a synergistic mechanism in which the mesoporous LDH/MXene enhances physical absorption of azo-dyes, while the AuNCs/LDH heterostructure promotes their chemical degradation. Considering its high decolorization activity, high cycle stability, reusability and controllable economic cost, our results provide a promise HEMDMHs candidate for the treatment of azo-dye wastewater.