It is highly desirable to enhance the charge separation and introduce catalytic functions for efficient water splitting into hydrogen on g-C 3 N 4 . Herein, heterojunctions of PCN-222(M)/g-C 3 N 4 -AA were successfully synthesized through the in-situ hydrothermal method, where metallic ions (M) were strategically incorporated into porphyrinic metal-organic framework (MOF) ligands. This heterojunction design strategy is considered to establish directional charge transfer channels for photogenerated electron-hole (e − -h + ) pairs and thereby enhance its separation efficiency. Remarkably, the 1 % PCN-222(Pd)/g-C 3 N 4 -AA composite demonstrated superior photocatalytic hydrogen evolution performance, achieving a rate of 2338.17 μmol·g −1 ·h −1 . This rate was 3.23 times higher than that of pure g-C 3 N 4 and 2.79 times higher than that of g-C 3 N 4 -AA. The composite morphology was characterized by a series of physicochemical properties. Bandgap analysis via Tauc plot revealed that metal ion doping in the porphyrin center effectively modulates the HOMO-LUMO levels at the composite interface. First-principles calculations coupled with hydrogen adsorption free energy analysis elucidated how interfacial engineering between PCN-222(M) and g-C 3 N 4 -AA governs heterostructure formation and charge transfer pathways. This work systematically deciphers the synergistic effects of bimetallic MOF integration and provides insights into the underlying photocatalytic reaction mechanism.
Hao Zhang,Qiuye Li,Bowen Li,Bo Weng,Zhihong Tian,Jianjun Yang,Johan Hofkens,Feili Lai,Tianxi Liu
We report a porous metal–organic framework loaded with single Pt atoms, namely PCN-222(Pt) nanorods, which are prepared by the self-assembly of Pt-metalized tetrakis(4-carboxyphenyl)porphyrin ligand with a Zr 6 cluster. The mass-loading of Pt in the synthesized PCN-222(Pt) is up to 4.67%, and can be accurately controlled by using an in-situ reaction strategy. Remarkably, the PCN-222(Pt) exhibits a highly efficient photocatalytic hydrogen production rate of 614 μmol g -1 h −1 , which is 7.4 times higher than that of PCN-222 (an isostructural sample to PCN-222(Pt) without coordinated Pt ions in the porphyrin rings). The apparent quantum efficiency of PCN-222(Pt) reaches up to 1.049% at 420 nm. Electron paramagnetic resonance spectra confirm the as-formed intermediate Zr III , obtained from the reduction of Zr IV species, participates in the photocatalytic reaction. Density functional theory calculations demonstrate the positive role that single Pt atoms in PCN-222(Pt) play in optimizing the corresponding hydrogen binding energy. The existence of this dual reaction mechanism in PCN-222(Pt) greatly and synergistically boosts the photocatalytic H 2 production activity.
The emergence of antibody-drug conjugates (ADCs) targeting trophoblast cell-surface antigen-2 (Trop-2) has reshaped the therapeutic landscape of advanced breast cancer. Accurate profiling of the Trop-2 status of tumor cells can facilitate the identification of patients who will benefit from Trop-2-targeting therapy; however limited analytical method has hindered this process. In this study, we have proposed a specific and sensitive biosensor for visual tracking of the Trop-2 status of breast cancer cells based on tetrahedral DNA nanostructure (TDN)-decorated Fe-based metal-organic framework nanoparticles (TDN-PCN-222 (Fe)). In the design, a dual-aptamer-assisted biomimetic capture strategy shows high capture efficiency while maintaining the viability and original phenotype of captured cells, ensuring the accurate profiling of the Trop-2 status. Meanwhile, by using the high intrinsic peroxidase activity and excellent targeting ability of Trop-2-specific aptamer-linked TDN-PCN-222 (Fe), specific detection of Trop-2-positive tumor cells can be achieved with a limit of detection (LOD) of 10 cells/mL, and the Trop-2 status of tumor cells can be visually tracked. Moreover, the proposed biosensor has been successfully used for tracking the Trop-2 status of tumor cells in breast cancer tissues, suggesting that our method has great promise for clinical applications.
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