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Abstract: Covalent organic frameworks (COFs) are emerging as a class of photocatalyst for solar energy utilization. The separation of photogenerated excitons in COFs is crucial for their photocatalytic performance. Herein, we report a strategy to tune the electronic structure of COFs by implanting Zn ions within the framework to facilitate the separation and utilization of the photoinduced charges. Zn ions are incorporated within the shell of hollow COF cages (Zn@H‐TpPa) by a sacrificial template method with a formation of hollow cages. The implantation of Zn ions within the framework results in a redistribution of electron density and an increment of the polarity of the COF, as evidenced by experimental and computational analyses, and thus contributes to the separation and transport of charge carries. The Zn@H‐TpPa shows enhanced photocatalytic H2 production efficiency as compared to TpPa. The results demonstrate a new way to optimize the electronic structure of COFs for photocatalysis. [ABSTRACT FROM AUTHOR]

Crystalline covalent organic frameworks (COFs) are porous polymeric semiconductors with network topologies, which are built from the integration of selected organic blocks with covalent bond linkages. They have shown great promise for artificial photosynthesis, owing to broad light harvesting, high crystallinity, and high carrier mobility. This Minireview introduces state‐of‐the‐art COF photocatalysts based on different linkages and discusses the origin of photocatalytic activities for hydrogen evolution. Three typical COF photocatalysts, with linkages including imine (−C=N−), β‐ketoenamine (O=C−C=C−NH−), and vinylene (−C=C−), are discussed with a particular focus on the advancements in synthetic methodologies and structural design, as well as photoelectronic properties that are relevant to photocatalytic performance. The Minireview is expected to elucidate their structure–property relationships and the way to design photoactive COFs with enhanced performances. [ABSTRACT FROM AUTHOR]

Facile fabrication of nanocatalysts consisting of metal nanoparticles (NPs) anchored on a functional support is highly desirable, yet remains challenging. Covalent organic frameworks (COFs) provide an emerging materials platform for structural control and functional design. Here, a facile one‐pot in situ reduction approach is demonstrated for the encapsulation of small Pd NPs into the shell of COF‐derived hollow polyamine spheres (Pd@H‐PPA). In the one‐pot synthetic process, the nucleation and growth of Pd NPs in the cavities of the porous shell take place simultaneously with the reduction of imine linkages to secondary amine groups. Pd@H‐PPA shows a significantly enhanced catalytic activity and recyclability in the tandem dehydrogenation of ammonia borane and selective hydrogenation of nitroarenes through an adsorption–activation–reaction mechanism. The strong interactions of the secondary amine linkage with borane and nitroarene molecules afford a positive synergy to promote the catalytic reaction. Moreover, the hierarchical structure of Pd@H‐PPA allows the accessibility of active Pd NPs to reactants. [ABSTRACT FROM AUTHOR]

Photocatalytic conversion of CO2 into value‐added chemical fuels is a promising approach to address the depletion of fossil energy and environment‐related concerns. Tailor‐making the electronic properties and band structures of photocatalysts is pivotal to improve their efficiency and selectivity in photocatalytic CO2 reduction. Herein, a covalent triazine‐based framework was developed containing electron‐donor triphenylamine and electron‐acceptor triazine components (DA‐CTF). The engineered π‐conjugated electron donor–acceptor dyads in DA‐CTF not only optimized the optical bandgap but also contributed to visible‐light harvesting and migration of photoexcited charge carriers. The activity of photocatalytic CO2 reduction under visible light was significantly improved compared with that of traditional g‐C3N4 and reported covalent triazine‐based frameworks. This study provides molecular‐level insights into the mechanism of photocatalytic CO2 reduction. [ABSTRACT FROM AUTHOR]

Photocatalytic CO2 reduction into carbonaceous feedstock chemicals is a promising renewable energy technology to convert solar energy and greenhouse gases into chemical fuels. Here, a covalent triazine‐based framework (CTF) is demonstrated as an efficient cocatalyst to reduce CO2 under visible‐light irradiation. The nitrogen‐rich triazine moieties in CTF contribute to CO2 adsorption, while the periodical pore structure of CTF favors the accommodation of CO2 and electron mediator. Immobilization of cobalt species onto CTF promotes the photocatalytic activity with a 44‐fold enhancement over pristine CTF and the optimal CO production rate of the obtained Co/CTFs was up to 50 μmol g−1 h−1. The results of solid‐state UV‐vis diffuse reflectance spectra (UV‐vis DRS), CO2 adsorption and electrochemical impedance spectroscopy (EIS) illustrated that the increased activity was ascribed to the enhanced CO2 capture capacity, improved absorption of visible‐light and facilitated the transfer of charge from CTF to CO2 molecules. The CTF not only serves as a substrate for active Co species, but also bridges the photosensitizer with cobalt catalytic sites for the efficient transfer of photoexcited electrons. This work highlights the capability and ease of fabricating covalent organic framework‐based photocatalytic systems that are potentially useful for energy‐conversion applications. [ABSTRACT FROM AUTHOR]

The protein tyrosine phosphatase PTP1B, which is encoded by PTPN1, is a ubiquitously expressed nonreceptor protein tyrosine phosphatase. PTP1B has long been known to negatively regulate insulin and leptin receptor signalling. Recently, it was reported to be aberrantly expressed in cancer cells and to function as an important oncogene. In this study, we found that PTP1B protein levels are dramatically increased in breast cancer (BC) tissues and that PTP1B promotes the proliferation, and suppresses the apoptosis, of both HER2‐positive and triple‐negative BC cell lines. Bioinformatics analysis identified that the miRNA, miR‐193a‐3p, might potentially target PTP1B. We demonstrate that miR‐193a‐3p regulates PTP1B in BC cells and that it regulates the proliferation and apoptosis of BC cells by targeting PTP1B, both in vitro and in vivo. In conclusion, this study confirms that PTP1B acts as an oncogene in BC and demonstrates that miR‐193a‐3p can serve as a tumour suppressor gene in BC by targeting PTP1B. Dysregulation of miR‐193a‐3p leads to PTP1B overexpression via a post‐transcriptional mechanism in HER2‐positive and triple‐negative breast cancer (BC) cells. The miR‐193a‐3p/PTP1B regulatory axis promotes cell proliferation, suppresses apoptosis and ultimately accelerates BC progression. [ABSTRACT FROM AUTHOR]

Abstract: MoS2 quantum dots (QDs)‐modified covalent triazine‐based framework (MoS2/CTF) composites are synthesized through an in situ photodeposition method. MoS2 QDs are well distributed and stabilized on the layers of CTFs by coordination of the frameworks to MoS2. The QDs–sheet interactions between MoS2 and CTFs facilitate interfacial charge transfer and separation. As a consequence, the composites exhibit outstanding photocatalytic activity and stability for hydrogen evolution under visible light irradiation (λ≥420 nm), that exceed those over pristine CTFs and MoS2‐modified g‐C3N4 (MoS2/g‐C3N4) composite, making them promising materials for solar energy conversion. [ABSTRACT FROM AUTHOR]

Despite extensive efforts dedicated to researching two-dimensional (2D) transition metal oxides (TMOs), significant challenges still remain to simplify their synthesis and improve the activity and reusability of these materials. In this work, we prepared a 2D Cu-containing layered double oxide (CuLDO) under mild conditions. Only via stirring LDO in diluted Cu solution at room temperature could ion exchange between Mg in LDO and Cu ions from that solution allow fixing of Cu onto the surfaces of LDO nanosheets with good dispersion at a high density. The obtained CuLDO was then annealed to give CuOx-rich nanosheets (denoted as c-CuLDO), which maintained a thin thickness of 5–9 nm with a flowers-like architecture thanks to the structural memory of the source materials. The excellent morphology of CuOx-based nanosheets helped to avoid the restacking of nanosheets. Such a c-CuLDO outperformed many other reported Cu-based nanomaterials as a catalyst in phenol degradation (k = 0.335 min−1) because c-CuLDO could efficiently activate persulfate to generate abundant amounts of sulfate radical (SO4Ṗ−). Furthermore, the catalytic activity of used c-CuLDO could be restored by a simple hydrothermal treatment. The developed chemistry could also be used to remove copper ions from wastewater, generating value-added Cu-based nanomaterials and eliminating waste at the same time. The current results may inspire the design of novel low dimensional nanomaterials that are difficult to synthesize directly by conventional bottom-up strategies. [ABSTRACT FROM AUTHOR]