Mo-Based Heterogeneous Interface and Sulfur Vacancy Synergistic Effect Enhances the Fenton-like Catalytic Performance for Organic Pollutant Degradation

Abstract

Heterogeneous Fenton-like reactions (HFLRs) based on the in situ electrochemical generation of hydrogen peroxide (H 2 O 2 ) are one of the green methods to remediate organic pollutants in wastewater. However, the design of Fenton-like catalysts with specific active sites and high pollutant degradation rate is still challenging. Here, MoS 2 −MoC and MoS 2 −Mo 2 N catalytic cathodes with heterojunctions were successfully prepared, and the mechanism by which hydroxyl radicals and singlet oxygen ( 1 O 2 ) were generated cleanly without adding chemical additives other than oxygen was clarified. The composite catalysts contained more sulfur vacancies, and the catalytic cathode achieved a high paracetamol pollutant degradation efficiency with 0.17 kWh g −1 TOC specific energy consumption. And almost 5 times higher activity was achieved compared to a pure MoS 2 catalytic cathode. Experimental studies confirmed that the production of 1 O 2 was based on the transformation of superoxide radicals by Mo 6+ , and 1 O 2 accounted for approximately 66% of the total degradation and enhanced the nonradical behavior in the reaction. This work provides a sustainable strategy for pollutant utilization, which is valuable for solving the difficult problems of HFLRs and developing new environmental remediation technologies.

Sulfur Vacancies in Pyrite Trigger the Path to Nonradical Singlet Oxygen and Spontaneous Sulfamethoxazole Degradation: Unveiling the Hidden Potential in Sediments

“…Natural pyrite possesses inherent defects on its surface, and compared with common sulfur sites, SVs are notable for their stronger binding affinity with compounds . X-ray photoelectron spectroscopy (XPS) and EPR are effective in analyzing surface defect types and concentrations . As shown in Figure S15, various sulfur species, including (S 2 ) 2– -bulk, (S 2 ) 2– -surface, SO 4 2– , and S 0 /S n 2– , were detected in the XPS spectrum of S 2p (Table S2).…”

“…Under illumination, a decline in ROS detection was attributed to the strong adsorption of ROSs by surface oxygen vacancies . Prior studies proposed that SVs, with high surrounding electron density, ,,− might act as reduction reaction sites for radical ROS capture. SV sites exhibited strong adsorption of •OH within an energetically favorable adsorption energy. , It was reasonable to infer that ROSs generated in photoreactions were not entirely utilized for contaminant degradation, explaining the lower SMX removal observed under light compared to that under darkness.…”

“…48 X-ray photoelectron spectroscopy (XPS) and EPR are effective in analyzing surface defect types and concentrations. 49 As shown in Figure S15, various sulfur species, including (S 2 ) 2− -bulk, (S 2 ) 2− -surface, SO 4…”

Visible-Light-Induced Photocatalytic Degradation of Rhodamine B Dye Using a CuS/ZnS p-n Heterojunction Nanocomposite under Visible-Light Irradiation

“…Photo-Fenton MoS 2 /Mo 2 N hydrothermal 20 mg L −1 paracetamols 71% degradation in 120 min under UV light [14] Electrochemical SA/TiO 2 immersion 5 mg L −1 p-nitrophenol 5% degradation in 120 min under UV light and 5% in 180 min under visible light [15] Ozonation Fe 2 O 3 /S-C 3 N 4 one-pot in situ 10 mg L −1 methylene blue (MB) dye 96% removal in 240 min under UV light [16] Sonolysis Cu x S/ZnO/TiO 2 spray pyrolysis 0.58 mg L −1 phenol 72% degradation in 600 min under UV light [17] Photocatalysis CoS 2 /MoS 2 hydrothermal 10 mg L −1 rhodamine B (RhB) dye 78% degradation in 60 min under visible light [18] Photocatalysis g-C 3 N 4 (SCN)/TiO 2 electrospinning 50 mg L −1 congo red (CR) dye 100% degradation in 60 min under UV light [19] Photocatalysis S@GO/TiO 2 ultrasonication 0.3 mg L −1 methylene blue (MB) dye 93% degradation in 120 min under UV light [20] Photocatalysis is one of the most researched AOPs due to its high degradation efficiency and continuously evolving nature, and it being regarded as a green, sustainable water treatment technology [8]. However, the application of common semiconductor photocatalysts such as TiO 2 and ZnO is limited by their wide bandgap energy, which makes them active under UV light irradiation only [21].…”

Nanocatalysts for modulating antitumor immunity: fabrication, mechanisms and applications

“…3F). 66 In addition to Fe, several transitional metals have been found with Fenton or Fenton-like catalytic activity, including Cu, 67 Mn, 68 Co, 69 Ti, 70 V, 71 Pd, 72 Ag, 73 Mo, 74 Ru, 75 W, 76 Ce, 77 and others. 78 In 2016, chemodynamic therapy (CDT) as a novel treatment modality was defined based on Fenton catalysis.…”