MoS₂/FeS Nanocomposite Catalyst for Efficient Fenton Reaction

Abstract

Nanocomposites containing FeS as catalyst and MoS2 as cocatalyst have been synthesized toward efficient heterogeneous Fenton reaction. The deposition of FeS nanoparticles in situ on the surface of MoS2 nanosheets creates strong contact between the two components and generates a large number of exposed Mo6+ sites and sulfur vacancies, which contribute to the enhanced degradation rate by accelerating Fe3+/Fe2+ cycling and ensuring rapid electron transfer. In addition, the MoS2/FeS nanocomposite catalysts exhibit the best performance at near-neutral conditions (pH 6.5), which solves the challenges in conventional Fenton reactions such as leaching of metal ions, the formation of iron slurry, and the need of adjusting solution pH. Further, the nanocomposite can maintain high efficiency after many recycling experiments. It is believed that the MoS2/FeS nanocomposite represents an efficient heterogeneous Fenton catalyst that can greatly promote the performance of advanced oxidation processes (AOPs) for solving practical environmental issues.

Enhancing Tumor Catalytic Therapy by Co‐Catalysis

“…According to potassium thiocyanate (KSCN) assay (Figure 3c), in conventional Fe 2+ ‐triggered Fenton reactions, the concentration of Fe 3+ increased significantly in 5 min of reaction, as a consequence of the differential reaction kinetics between the first and the second steps of Fenton reactions. The amount of accumulated Fe 3+ could only be reduced gradually after Fe 2+ exhaustion [21] . Comparatively, for MSFP nanosheet‐triggered Fenton reactions, the amount of Fe 2+ accounts for 66 % of overall Fe amount of the nanosheet after 5 min of reactions according to XPS measurement (Figure 3d), which is almost the same as that of Fe 2+ in the nanosheet before reactions (Figure S13b).…”

“…The amount of accumulated Fe 3 + could only be reduced gradually after Fe 2 + exhaustion. [21] Comparatively, for MSFP nanosheet-triggered Fenton reactions, the amount of Fe 2 + accounts for 66 % of overall Fe amount of the nanosheet after 5 min of reactions according to XPS measurement (Figure 3d), which is almost the same as that of Fe 2 + in the nanosheet before reactions (Figure S13b). In addition, a stronger peak at 236 eV could be observed in the Mo 3d XPS spectrum of MSFP nanosheet after Fenton reactions, corresponding to Mo 6 + specie (Figure 3e), [22] while only a weak peak at the same binding energy could be observed in the Mo 3d XPS spectrum of pristine MSFP.…”

Enhancing Tumor Catalytic Therapy by Co‐Catalysis

“…These vacancy defects can act as the electron donors to increase surface electron density of MSFP nanosheets, [20] which was also demonstrated by the results of XPS and zeta potential analysis (Figure S13a, S18). These defects benefit the adsorption of H 2 O 2 , energetically favoring ⋅OH generation by increasing the concentration of H 2 O 2 reactants around the catalytic sites, as well as donating electrons to H 2 O 2 to promote its decomposition into ⋅OH [21] . More importantly, the Mo 4+ sites can be exposed considerably and become more reactive after S atom removal, thus significantly promoting the reduction of Fe 3+ to Fe 2+ [5] …”

Recent advances in MoS2-based materials for electrocatalysis

“…(6) In addition to the fields of HER/NRR/CO 2 RR activity, in just the past few years, owing to its superior electronic properties and capacities, MoS 2 has also been widely employed in a wide range of applications such as the environmental applications, 222 electrochemical oxygen reduction reaction (ORR), 223 NO reduction, 224 supercapacitors, 225 sensors, 226 secondary batteries ( e.g. , Li-ion batteries (LIBs), 227 Li–S batteries, 228 Li–O 2 batteries, 229 Na–S batteries, 230 Na–O 2 batteries, 231 Mg-ion batteries, 232 Al-ion batteries, 233 and Na-ion batteries, 234 etc.…”