Strategies to improve photocatalytic activity of nanoscale zero valent iron decorated MoS2: Construction of novel S-scheme nanoflower heterojunction with advanced visible-light degradation of tetracycline

Although both MoS2 and nanoscale zero valent iron have presented bright prospects for environmental remediation. The constrained conductivity of MoS2 and the passivation and aggregation of Fe0 still retained challenges. Given this, innovative strategies of activating the passivation layers of Fe0 into semiconductors by photocatalysis and constructing S-scheme nanoflower heterojunctions with MoS2 (Fe0@MoS2) were fabricated. The results revealed that Fe0@MoS2 exhibited enhanced efficiency toward visible-light degradation of tetracycline, which was 3.20 and 1.27 times as high as that of bare MoS2 and Fe0, respectively. The boosted activity was attributed to the cooperation of MoS2 and Fe0. The synergistic effects stemmed from the following mechanisms: (1) the fluffy nanoflower-like structure and widened interlayer spacing of MoS2 facilitated the dispersion of Fe0, guaranteeing its enhanced adsorption and reduction capacity; (2) the conductivity of MoS2 was remarkably improved due to the doping of the passivation layers of Fe0, and the layers were activated as semiconductors by visible-light, causing the establishment of S-scheme heterojunctions between them and MoS2. Moreover, the kinetics, stability, recyclability, and optical characteristics of Fe0@MoS2 were confirmed comprehensively. The potential routes for TC elimination deriving from the action of •O2− and h+ were proposed. These findings provided novel strategies for construction of Fe0-based S-scheme heterojunction with advanced visible-light-induced degradation performance.