High entropy nanoparticles of CoCrXFeNi (X=Al, Cu, Mn) loaded on activated carbon for efficient degradation of methylene blue

Different from the reported catalysts such as metallic glasses ribbons and ball-milled high entropy alloy powder, high entropy alloy nanoparticles (HEA NPs) have attracted wide attention for compelling and functional catalytic properties to degrade methylene blue (MB) dye. CoCrXFeNi (X = Al, Cu, Mn) HEA NPs with different loadings were synthesized by impregnation-adsorption method on activated carbon (AC). Nanoscale HEA NPs with maximized configuration mixing entropy are composed of a single solid-solution face-centered cubic (FCC) phase and the nanocomposites show distinctive porous architectures and large specific surface area (average S_BET = 632.7 m²/g) for 10 wt.% loadings. The reaction rates (k_obs) of 10 wt.% CoCrAlFeNi and CoCrMnFeNi HEA NPs-AC for MB degradation are 0.1998 and 0.1830 min⁻¹ and show comparable intrinsic catalytic performance to amorphous ribbons and HEA powders. The HEA NPs can effectively decompose MB molecule via nanoscale galvanic cell effect which provides a promising material in dye decomposition and mineralization.