Al/Cu-PILC as a Photo-Fenton Catalyst: Paracetamol Mineralization

Electronic structure regulation of Fe single atom coordinated nitrogen doping MoS2 catalyst enhances the Fenton-like reaction efficient for organic pollutant control

An efficient cathode for a Fenton-like reaction based on hydrogen peroxide (H2O2) has significant implications for the potential application of the advanced oxidation process. However, the low H2O2 selectivity and efficient activation remain challenging in wastewater treatment. In the present study, a single Fe atom doped, nitrogen-coordinated molybdenum disulfide (Fe1/N/MoS2) cathode that exhibited asymmetric wettability and self-absorption molecular oxygen was successfully prepared for pollutant degradation. The X-ray absorption near-edge structure and extended X-ray absorption fine structure of Fe1N3 in the Fe1/N/MoS2 catalyst were determined. The electronic structure demonstrated favorable H2O2 selectivity (75%) in a neutral solution and the cumulative hydroxyl radical concentration was 14 times higher than the pure carbon felt. After 10 consecutive reaction experiments, the removal ratio of paracetamol still reached 97%, and the catalytic performance did not decrease significantly. This work deeply understands the catalytic mechanism of Fenton-like reaction between single Fe atom and MoS2 double reaction sites, and proves that the regulation of the electronic structure of Fe single atom is an effective strategy to improve the activity of Fenton-like reaction.

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

Heterogeneous Fenton-like reactions (HFLRs) based on the in situ electrochemical generation of hydrogen peroxide (H₂O₂) 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, MoS₂-MoC and MoS₂-Mo₂N catalytic cathodes with heterojunctions were successfully prepared, and the mechanism by which hydroxyl radicals and singlet oxygen (¹O₂) 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 MoS₂ catalytic cathode. Experimental studies confirmed that the production of ¹O₂ was based on the transformation of superoxide radicals by Mo⁶⁺, and ¹O₂ 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.

Photo-Oxidation of Glycerol Catalyzed by Cu/TiO2

In the present study, glycerol was oxidized by photocatalysis to glyceraldehyde, formaldehyde, and formic acid. Copper-doped TiO2 was synthesized by the evaporation-induced self-assembly approach and it was used as catalyst during the glycerol photo-oxidation reactions. The prepared mesoporous material exhibited high specific surface area (242 m2/g) and band gap energy reduction of 2.55 eV compared to pure titania (3.2 eV) by the synthesis method due to the presence of copper cations (Cu2+ identified by XPS). The catalyst showed only anatase crystalline phase with nanocrystals around 8 nm and irregular agglomerates below 100 μm. The selectivity and formation rate of the products were favored towards formaldehyde and glyceraldehyde. The variables studied were catalyst amount, reaction temperature, and initial glycerol concentration. The response surface analysis was used to evaluate the effect of the variables on the product’s concentration. The optimized conditions were 0.4 g/L catalyst, 0.1 mol/L glycerol, and temperature 313.15 K. The response values under optimal conditions were 3.23, 8.17, and 1.15 mM for glyceraldehyde, formaldehyde, and formic acid, respectively. A higher selectivity towards formaldehyde was observed when visible light was used as the radiation source. This study is useful to evaluate the best reaction conditions towards value-added products during the oxidation of glycerol by photocatalysis using Cu/TiO2.