Bimetallic Co2+Cr3+LDH anchored AgCl as excellent solar-light-responsive Ag-decorated type II nano-heterojunction for photodegradation of various dyes

Abstract

The widespread use of organic dyes in industrial applications consistently endangers the eco-system health. The photocatalytic degradation of organic wastewater has been recognized as a highly promising strategy for combating this environmental issue. Herein, A series of bimetallic Co2+Cr3+LDH anchored AgCl as excellent solar-light-responsive Ag-decorated staggered nano-heterojunctions were constructed using a facile sono-precipitation method and their performance toward degradation of various azo dyes were investigated. Ag-AgCl-CoCrLDH(3:1)-PU exhibited excellent photocatalytic activity by degrading acid orange 7, eosin Y, rhodamine B, methylene blue, and methyl orange with respective efficiencies of 100.0 %, 98.4 %, 94.0 %, 88.7 %, and 86.2 %. The photocatalyst characteristics were determined using XRD, FESEM, TEM, EDX, BET-BJH, FTIR, and UV–vis DRS techniques. The DRS analysis of Ag-AgCl-CoCrLDH(3:1)-PU photocatalyst (Eg = 2.37 eV) revealed that the introducing of LDH in the heterostructure, along with the SPR effect of Ag particles, increased the visible light absorption capacity. Furthermore, the staggered band gap accelerated charge carrier transformation, resulting in a lower recombination rate. Based on the BET-BJH results, integration of LDH combined with ultrasound irradiation increased the SBET and pore volume (Vp) to 19.5 m2/g and 0.052 cm3/g, respectively (compared to bare Ag-AgCl-PU with SBET and Vp of 3.4 m2/g and 0.004 cm3/g, and non-sonicated Ag-AgCl-CoCrLDH(3:1)-P with SBET and Vp of 16.8 m2/g and 0.016 cm3/g). The FESEM and TEM images clearly displayed the significant influence of sonication on well dispersion and de-agglomeration of nanoparticles. Subsequently, the reusability of nanophotocatalyst was examined, and a possible degradation mechanism was suggested.