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Single‐atom photocatalysts have shown their fascinating strengths in enhancing charge transfer dynamics; however, rationally designing coordination sites by metal doping to stabilize isolated atoms is still challenging. Here, a one‐unit‐cell ZnIn2S4 (ZIS) nanosheet with abundant Cu dopants serving as the suitable support to achieve a single atom Pt catalyst (Pt1/Cu–ZIS) is reported, and hence the metal single atom–metal dopant interaction at an atomic level is disclosed. Experimental results and density functional theory calculations highlight the unique stabilizing effect (Pt–Cu interaction) of single Pt atoms in Cu‐doped ZIS, while apparent Pt clusters are observed in pristine ZIS. Specifically, Pt–Cu interaction provides an extra coordination site except three S sites on the surface, which induces a higher diffusion barrier and makes the single atom more stable on the surface. Apart from stabilizing Pt single atoms, Pt–Cu interaction also serves as the efficient channel to transfer electrons from Cu trap states to Pt active sites, thereby enhancing the charge separation and transfer efficiency. Remarkably, the Pt1/Cu–ZIS exhibits a superb activity, giving a photocatalytic hydrogen evolution rate of 5.02 mmol g−1 h−1, nearly 49 times higher than that of pristine ZIS. [ABSTRACT FROM AUTHOR]

The activity of heterogeneous photocatalytic H2O2 activation in Fenton‐like processes is closely related to the local electron density of reaction centre atoms. However, the recombination of electron‐hole pairs arising from random charge transfer greatly restricts the oriented electron delivery to active center. Here we show a defect engineered iron single atom photocatalyst (Fe1‐Nv/CN, single Fe atoms dispersed on carbon nitride with abundant nitrogen vacancies) for the activation of H2O2 under visible light irradiation. Based on DFT calculations and transient absorption spectroscopy results, the engineered nitrogen vacancies serve as the electron trap sites, which can directionally drive the electrons to concentrate on Fe atoms. The formation of highly concentrated electrons density at Fe sites significantly improves the H2O2 conversion efficiency. Therefore, the optimized single atom catalyst exhibiting a higher ciprofloxacin degradation activity, which was up to 18 times that of pristine CN. [ABSTRACT FROM AUTHOR]

Photoinduced molecular oxygen activation offers a promising strategy for oxidative degradation of organic pollutants, but the critical step of oriented electron delivery from the active sites into the stable O 2 molecules presents a considerable challenge. Herein, we report the construction of a direct Z-scheme heterojunction with abundant nitrogen defects (α-Fe 2 O 3 /g-C 3 N 4) for powering molecular oxygen activation by steering a specific migration route. This specific interfacial photoelectron transfer pathway showcases the establishment of an effective sequential photoelectron transfer channels between α-Fe 2 O 3 and g-C 3 N 4. The nitrogen defects on the g-C 3 N 4 surface can not only serve as the oxygen adsorption sites, but also can act as the terminal electron sink to donate photoexcited high-energy electrons to the adsorbed O 2. Therefore, the optimized α-Fe 2 O 3 /g-C 3 N 4 exhibits greatly enhanced catalytic performance for molecular oxygen activation, and the degradation rate constant of tetracycline is 4.7 and 12 times higher than g-C 3 N 4 and α-Fe 2 O 3 , respectively. [Display omitted] • A novel defect-mediated Z-scheme α-Fe 2 O 3 /g-C 3 N 4 heterojunction is reported. • Z-type charge transfer pathway was proved by in situ-XPS, EPR and DFT calculations. • Nitrogen vacancy serves as adsorption site and electron sink for O 2 activation. • This efficient O 2 activation system shows excellent performance in TC degradation. [ABSTRACT FROM AUTHOR]