Singlet oxygen (1O2) is an excellent active species for the selective degradation of organic pollutions. However, it is difficult to achieve high efficiency and selectivity for the generation of 1O2. In this work, we develop a graphitic carbon nitride supported Fe single‐atoms catalyst (Fe1/CN) containing highly uniform Fe‐N4 active sites with a high Fe loading of 11.2 wt %. The Fe1/CN achieves generation of 100 % 1O2 by activating peroxymonosulfate (PMS), which shows an ultrahigh p‐chlorophenol degradation efficiency. Density functional theory calculations results demonstrate that in contrast to Co and Ni single‐atom sites, the Fe‐N4 sites in Fe1/CN adsorb the terminal O of PMS, which can facilitate the oxidization of PMS to form SO5.−, and thereafter efficiently generate 1O2 with 100 % selectivity. In addition, the Fe1/CN exhibits strong resistance to inorganic ions, natural organic matter, and pH value during the degradation of organic pollutants in the presence of PMS. This work develops a novel catalyst for the 100 % selective production of 1O2 for highly selective and efficient degradation of pollutants.

Single atom catalysts (SACs) with the maximized metal atom efficiency have sparked great attention. However, it is challenging to obtain SACs with high metal loading, high catalytic activity, and good stability. Herein, we demonstrate a new strategy to develop a highly active and stable Ag single atom in carbon nitride (Ag‐N2C2/CN) catalyst with a unique coordination. The Ag atomic dispersion and Ag‐N2C2 configuration have been identified by aberration‐correction high‐angle‐annular‐dark‐field scanning transmission electron microscopy (AC‐HAADF‐STEM) and extended X‐ray absorption. Experiments and DFT calculations further verify that Ag‐N2C2 can reduce the H2 evolution barrier, expand the light absorption range, and improve the charge transfer of CN. As a result, the Ag‐N2C2/CN catalyst exhibits much better H2 evolution activity than the N‐coordinated Ag single atom in CN (Ag‐N4/CN), and is even superior to the Pt nanoparticle‐loaded CN (PtNP/CN). This work provides a new idea for the design and synthesis of SACs with novel configurations and excellent catalytic activity and durability.

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Carbon quantum dots/CdS quantum dots/g-C3N4 (CDs/CdS/GCN) photocatalysts have been designed and prepared. Systematic characterization such as XRD, SEM, TEM, UV, and XPS, were done to confirm the composite catalysts of CDs/CdS/GCN. The simultaneous photocatalytic production of hydrogen coupled with degradation of organic contaminants (p-chlorophenol, bisphenol A, and tetracycline, called 4-NP, BPA, and TTC, respectively) was efficiently realized over the resultant CDs/CdS/GCN composites. The as-prepared 3%CDs/10%CdS/GCN exhibits high efficiency of photocatalytic hydrogen evolution from water splitting and photodegradation rates of organic pollutants in aqueous solutions of 4-NP, BPA, and TTC under visible-light illumination since the formation of interfaces between CdS quantum dots and GCN nanosheets leads to an efficient charge separation efficiency. Furthermore, as compared to that in a pure water system, the photocatalytic evolution rate of H2 over the 3%CDs/10%CdS/GCN catalyst in the presence of 4-NP solution is decreased, while the H2 evolution rates increase when BPA or TTC solution were used instead of 4-NP solution under visible-light irradiation. Consequently, 4-NP shows higher photodegradation efficiency than do BPA and TTC in the simultaneous photocatalytic oxidation and reduction system. Aiming at making clear the relationship between the photocatalytic H2 production and the photocatalytic pollutants degradation, density functional theory (DFT) calculations, and liquid chromatography mass spectrometry (LC-MS) were used for a systematic investigation. The present work reports a plausible mechanism of photodegradation of different organic contaminants with synchronous photocatalytic H2 evolution from water and the photocatalytic enhancement of the CDs/10%CdS/GCN catalysts.