Large-Scale Continuous and In Situ Photosynthesis of Hydrogen Peroxide by Sulfur-Functionalized Polymer Catalyst for Water Treatment.

Photocatalytic H2 O2 generation system based on polymer catalyst receives increasing attention in recent years; however, the insufficient charge separation efficiency and low oxygen adsorption/activation capacity severely limit their potential application. In this study, a sulfur (C=S) functionalized polymer catalyst is reported through a green water-mediated and catalyst-free multi-component reactions (MCRs) route. The sulfur functional group endows the polymer with a suitable energy band and facilitates the separation of photogenerated electron-hole pair. The reported polymer achieves a high H2 O2 production efficiency (3132 µmol g-1 h-1 ) in pure water without oxygen aeration. To demonstrate their potential in in situ wastewater treatment, a panel reactor system (20×20 cm) is constructed for large-scale production of H2 O2 , which realizes continuous degradation of emerging pollutants including antibiotics and bisphenol A under natural sunlight irradiation condition. The H2 O2 utilization efficiency of the photo-self-Fenton system using in situ generated H2 O2 is found 7.9 times higher than that of the traditional photo-Fenton system. This study offers new insights in green synthesis and design of functional polymer photocatalyst, and demonstrates the feasibility of panel reactor system for large-scale continuous H2 O2 photocatalytic production and water treatment.

Cyano-Regulated Organic Polymers for Highly Efficient Photocatalytic H2 O2 Production in Various Actual Water Bodies.

Photocatalytic production of H2 O2 has drawn significant attention in recent years, but the yield rate of current photocatalytic systems is still unsatisfactory. Moreover, the presence of various components in actual water bodies will consume the photogenerated charges and deactivate the catalyst, severely limiting the real applications of photocatalytic H2 O2 production. Herein, a cyano-modified polymer photocatalyst is synthesized by Knoevenagel condensation with subsequent thermal polymerization. The introduction of cyano group and sulfer (S), oxygen (O) elements modulates the microstructure and energy band of the polymer catalyst, and the cyano group sites can effectively adsorb and activate O2 , realizing the generation of H2 O2 in the two-step single-electron oxygen reduction process. The reported system achieves high H2 O2 generation rate up to 1119.2 µmol g-1 h-1 in various water bodies including tap water, river water, seawater, and secondary effluent. This simple and readily available catalyst demonstrates good anti-interference performance and pH adaptability in photocatalytic H2 O2 production in actual water bodies, and its photodegradation and sterilization applications are also demonstrated. This study offers new insights in developing polymer catalysts for efficient photocatalytic production of H2 O2 in various water bodies for practical application.

ZnS-embedded porous carbon for peroxydisulfate activation: Enhanced electron transfer for bisphenol A degradation.

Transition metal sulfides have garnered increasing attention for their role in persulfate activation, a crucial process in environmental remediation. However, the function of metal sulfides without reversible valence changes, such as ZnS, remains largely unexplored in this context. Here we report ZnS-embedded porous carbon (ZnS-C), synthesized through the pyrolysis of Zn-MOF-74 and dibenzyl disulfide. ZnS-C demonstrates remarkable activity in activating peroxydisulfate (PDS) across a wide pH range, enabling the efficient mineralization removal of bisphenol A (BPA). Through electrochemical investigation and theoretical simulations of charge density distributions, we unveil that the electron transfer from BPA to PDS mediated by the ZnS-C catalyst governs the reaction. This study, both in theory and experiment, demonstrates metal sulfide as electron pump that enhances electron transfer efficiency in PDS activation. These findings redefine the role of metal sulfide catalysts, shedding new light on their potential for regulating reaction pathways in PDS activation processes.