Rational design of C@MoS2@Ag2S heterojunction nanozymes for synergistic activation of H2O2 and persulfate toward enhanced p-nitrophenol degradation

C@MoS 2 @Ag 2 S heterojunction nanozyme was constructed. • C@MoS 2 @Ag 2 S presented exceptional peroxidase-like activity. • p-nitrophenol was efficiently degraded by C@MoS 2 @Ag 2 S through activating H 2 O 2 and PDS. In this study, a carbon-coated MoS 2 @Ag 2 S (C@MoS 2 @Ag 2 S) heterojunction nanozyme with superior peroxidase-like activity is prepared via heterojunction pre-construction followed by carbonization. The kinetic parameters toward H 2 O 2 are determined to be K m = 1.02 mM and V max = 38.08 × 10 −8 M·s −1 , and toward 3,3′,5,5′-tetramethylbenzidine (TMB) are K m = 0.14 mM and V max = 60.35 × 10 −8 M·s −1 . Notably, its affinity for H 2 O 2 is substantially higher than that of natural horseradish peroxidase (HRP, K m = 3.7 mM), and the catalytic efficiency (V max ) is also superior. Enhanced performance stems from three-component synergy improving electron transport, charge separation, and ROS generation. Through synergistically activating persulfate (PDS) and H 2 O 2 , SO 4 • ⁻ , •OH, and 1 O 2 are generated, which collectively degrade PNP, achieving 90% removal in 40 min. This study offers theoretical guidance for the controllable synthesis of biomass-derived carbon/metal sulfide heterojunction nanozyme and the design of dual-oxidant synergistic activation systems for degradation of organic pollutants. Download: Download high-res image (151KB) Download: Download full-size image