Regulating electronic configuration to fully exploit the potential of Pt single atoms for efficient photocatalytic hydrogen production is of great significance, but remains challenging. Herein, we report alkaline earth metals (AM) modified atomically dispersed Pt sites on graphitic carbon nitride (CN) for photocatalytic H₂ production. The results of XPS, XAFS and DFT calculation demonstrate that in these AMPt-CN (AM: Mg, Ca, Sr and Ba) catalysts, the incorporation of AM effectively increases the electron density of Pt single-atom and decreases the d-band center of Pt, concurrently reducing the free energy barrier for the hydrogen evolution reaction. Additionally, fs-TAS and photoelectric performance tests of catalysts reveal concurrent improvements in light absorption and charge separation efficiency with alkaline earth metal doping. Consequently, the optimized AMPt-CN achieve a remarkable hydrogen production rates of 2.79 (MgPt-CN), 1.55 (CaPt-CN), 2.12 (SrPt-CN) and 1.34 (BaPt-CN) mol g_Pt^-1 h^-1 with an high apparent quantum yield of 21.7%, 18.1%, 18.9% and 10.8%, respectively, superior to most of the reported carbon nitride based Pt single-atom catalysts. Noteworthily, together with energy band structure results, a prominent linear relationship between the hydrogen evolution activity and the corresponding conduction band potentials is established. These findings reveal a new perspective for in-depth comprehension of the role of alkaline earth metals in adjusting electronic properties of Pt single-atom catalysts for promoting photocatalytic performance.

S-scheme possesses superior redox capabilities compared with the II-scheme, providing an effective method to solve the innate defects of g-C₃N₄ (CN). In this study, S-doped g-C₃N₄/g-C₃N₄ (SCN-tm/CN) S-scheme homojunction was constructed by rationally integrating morphology control with interfacial engineering to enhance the photocatalytic hydrogen evolution performance. In-situ Kelvin probe force microscopy (KPFM) confirms the transport of photo-generated electrons from CN to SCN. Density functional theory (DFT) calculations reveal that the generation of a built-in electric field between SCN and CN enables the carrier separation to be more efficient and effective. Femtosecond transient absorption spectrum (fs-TAS) indicates prolonged lifetimes of SCN-tm/CN3 (τ₁: 9.7, τ₂: 110, and τ₃: 1343.5 ps) in comparison to those of CN (τ₁: 4.86, τ₂: 55.2, and τ₃: 927 ps), signifying that the construction of homojunction promotes the separation and transport of electron hole pairs, thus favoring the photocatalytic process. Under visible light irradiation, the optimized SCN-tm/CN3 exhibits excellent photocatalytic activity with the hydrogen evolution rate of 5407.3 μmol·g⁻¹·h⁻¹, which is 20.4 times higher than that of CN (265.7 μmol·g⁻¹·h⁻¹). Moreover, the homojunction also displays an apparent quantum efficiency of 26.8% at 435 nm as well as ultra-long and ultra-stable cycle ability. This work offers a new strategy to construct highly efficient photocatalysts based on the metal-free conjugated polymeric CN for realizing solar energy conversion.

Traditional surgical treatment is difficult to thoroughly remove esophageal squamous cell carcinomas (ESCC), and postoperative recurrence caused by residual tumor cells is a critical factor in the poor prognosis. Since surgical resection promotes the local angiogenesis at the tumor site, further exacerbating the proliferation and invasion of residual tumor cells, it is urgent to inhibit angiogenesis after surgery. Here, a functional peptide-based nanomedicine was obtained from peptide–drug conjugates, which are composed of a hydrophilic targeting motif (vascular endothelial growth factor family and their receptors (VEGFR) targeting peptide for anti-angiogenesis), and an ester-linked hydrophobic oridonin (ORI). The nanomedicine exhibits esterase-catalyzed disassembly and drug release, and significantly enhanced the anti-tumor efficacy of chemotherapeutics in a postoperative tumor recurrence model through synergistic anti-angiogenic strategies. This study provides an integrated solution for anti-angiogenesis-augmented chemotherapy and demonstrates the encouraging potential for postoperative treatment.