Design of active dual atom Ni-Co-2H-MoS2 catalyst: Synergistic effect of Ni-adsorption and co-catalysis for activating peroxymonosulfate

Abstract

Peroxymonosulfate (PMS)-based advanced oxidation processes synergistically activated by dual atom catalysts (DACs) have become a cutting-edge technology for environmental remediation. Herein, a Ni-Co-2H-MoS2 (NCMS) DAC was successfully prepared by introducing bimetals (Ni and Co) into the framework of the 2H-MoS2 co-catalyst through a host–guest strategy. The NCMS/PMS catalysis system exhibits significant decontamination performance for tetracycline, and its removal efficiency of 99.6% is 3.7 times and 4.0 times higher than that of the Ni-2H-MoS2/PMS and Co-2H-MoS2/PMS single atom catalysts, respectively. Besides, density functional theory (DFT) was employed to disclosure the role of the active sites of NCMS DAC, investigate the influence of heteronuclear diatomic doping on electron aggregation and delocalization, and analyze the mechanism of PMS activation and TC degradation. Experimental results and theoretical simulations demonstrate that Ni and Co atoms of NCMS exert a reasonable regulation effect on the coordination environment and electronic structure, thereby promoting PMS activation with a unique synergy mode. The introduction of Ni lowers the adsorption energy barrier of PMS on the DAC, facilitating subsequent PMS activation. Meanwhile, the interaction between Co and Mo accelerates valence restoration and evolution of Co2+/Co3+ and Mo4+/ Mo5+/ Mo6+, further improving catalytic activity. This work provides a novel strategy for the on-demand design of Fenton-like reactions by regulating microenvironment of the catalyst.