3D layer-by-layer amorphous MoSx assembled from [Mo3S13]2- clusters for efficient removal of tetracycline: Synergy of adsorption and photo-assisted PMS activation

Peroxymonosulfate (PMS) activation and photocatalysis are effective technologies to remove organic pollutants, but the adsorption effect of the catalyst is usually unheeded in degradation process. Herein, a bifunctional catalyst of amorphous MoSx (a-MoSx) with 3D layer-by-layer superstructure was synthesized by assembling basic active units [Mo3S13]2- of MoS2. The large interlayer spacing and high exposure of active sites render a-MoSx to have excellent synergy of adsorption and photo-assisted PMS activation for tetracycline (TC) degradation. Experiments and DFT calculation show that TC can be efficiently enriched on a-MoSx by pore filling, π-π interaction, hydrogen bonding and high adsorption energy. Subsequently, PMS can be quickly activated through electron transfer with a-MoSx, resulting in high TC degradation efficiency of 96.6% within 20 min. In addition, the synergistic mechanism of adsorption and photo-assisted PMS activation was explored, and the degradation pathway of TC was expounded. This work is inspirational for constructing bifunctional catalysts with superior synergistic adsorption and catalytic capabilities to remove refractory organic pollutants in water.