Science China Chemistry最新文献

Birefringence is crucial for birefringent crystals to modulate polarized light and nonlinear optical crystals to enable phase-matching. It is closely related to the arrangement of advantageous functional groups with large microcosmic polarizability anisotropy in the structure. Currently, designing crystals with large birefringence by modulating the arrangement of advantageous functional groups is still a challenge. In this work, the arrangement of the advantageous [B₃O₇] groups is optimized by introducing rigid tetrahedral [SO₄] groups, resulting in a novel boron-rich borosulfate, Na₂B₆SO₁₃, which exhibits unprecedented [B₆SO₁₃]_∞ double chain and an enhanced birefringence (Δn = 0.07 at 589.3 nm) against the borate parent LiB₃O₅. Theoretical calculations confirm that the birefringence is mainly attributable to the uniform alignment of [B₃O₇] groups. Na₂B₆SO₁₃ also possesses a deep ultraviolet (DUV) cutoff edge (λ < 185 nm). This work provides a feasible method to design DUV birefringent crystals with large birefringence by inducing the arrangement of advantageous functional groups.

Ferroelectric materials hold great promise in photocatalytic water splitting because their built-in electric field induced by the depolarization field can fulfill the separation of photogenerated carriers. However, a number of intrinsic charged vacancy defects are simultaneously generated to screen the depolarized field for stabilizing the crystal structure, always resulting in severe recombination of photogenerated carriers and thus poor overall water splitting activity. Herein, we proposed a strategy to promote the separation and transport of photogenerated carriers of ferroelectric photocatalysts by adjusting the ferroelectric polarization and altering the coordination environment of elements to reduce the defect concentration. Specifically, we prepared a series of Ta-doped PbTiO₃ with low Pb (V_Pb) and O (V_O) vacancy concentrations by reducing the polarization intensity and strengthening the Pb–O interaction. The Ta-doped PbTiO₃ shows efficient charge separation and greatly enhanced photocatalytic overall water splitting activity with the assistance of cocatalyst. This work highlights the importance of regulating ferroelectric polarization and vacancy defect concentration by the doping strategy in charge separation for photocatalytic water splitting.

The molecular engineering of fluorescent organic/polymeric materials, specifically those emitting in the deep red to near-infrared spectrum, is vital for advancements in optoelectronics and biomedicine. Perylene diimide (PDI), a well-known fluorescent scaffold, offers high thermal and photophysical stability but suffers from fluorescence quenching in solid or aggregate states due to intense π-π interactions. To mitigate this, simple and versatile methods for strong PDI aggregate emission without extensive synthetic demands are highly desirable but still lacking. Here, we report a straightforward strategy to enhance the solid-state emission of PDI by introducing certain degree of through-space charge transfer (TSCT) via controlled radical polymerization, which can efficiently distort the typical face-to-face PDI stacking, enabling greatly enhanced deep red emission. This is achieved by growing electron-donating star-shape styrenic (co)polymers from a multidirectional electron-accepting PDI initiator. The incorporation of polycyclic aromatic monomers further shifted the emission into the near-infrared region, albeit with a reduced intensity. Overall, the emission of the PDI-based TSCT polymers can be systematically manipulated by leveraging the balance between PDI stacking and the TSCT degree, as confirmed by both experimental study and theoretical calculations. Our approach circumvents complex synthetic procedures, offering highly emissive materials with large Stokes shifts and showing broad potential for optoelectronic technology.

Tandem hydroformylation/hydrogenation of olefins to alcohols is an appealing and challenging route that has received continuous interest. Herein, we report a bifunctional atomically dispersed Rh and Co catalyst (RhCo/Al₂O₃-10) prepared by a simple ball milling method that displays superior synergistic catalytic performance (>95% olefins conversion and >80% alcohols selectivity) and broad substrate scope for tandem hydroformylation/hydrogenation reaction, outperforming Rh/Al₂O₃, Co/Al₂O₃, and their physically mixed counterparts. In situ CO-DRIFTS, XPS, and kinetic experiments demonstrate that the electron interaction between Rh and Co atoms effectively lowers the apparent activation energy, thus promoting the tandem hydroformylation/hydrogenation reaction. This work not only presents a novel tandem hydroformylation/hydrogenation reaction system for converting olefins to alcohol but also throws light on the rational design of versatile bifunctional catalysts for on-demand synergistic catalysis.

Developing highly efficient Pt-based methanol oxidation reaction (MOR) catalysts is pivotal for direct methanol fuel cells. Phase engineering of nanomaterials offers a promising strategy to improve their catalytic performance, yet achieving phase modulation in one-dimensional nanowires (NWs) remains a great challenge. Herein, we report a facile and one-pot synthesis approach for the crystal-phase-controlled Pt-Sn intermetallic nanowires (NWs), realizing the crystal-phases regulation of face-centered cubic Pt₃Sn intermetallic NWs (FCC-Pt₃Sn INTNWs) and hexagonal close-packed PtSn intermetallic NWs (HCP-PtSn INTNWs) by adjusting the amounts of Sn precursors. Notably, the FCC-Pt₃Sn INTNWs exhibit high mass and specific activities of 6.4 A mg_Pt^-1 and 11.8 mA cm^-2, respectively, surpassing its counterparts, the HCP-PtSn INTNWs and commercial Pt/C catalysts. After a 10,000 s durability test, the FCC-Pt₃Sn INTNWs still maintain a mass activity of 5.6 A mg_Pt^-1, which is 24.3 times higher than that of commercial Pt/C catalyst. This dramatic enhancement of MOR performance is primarily attributed to the phasecontrolled structure and accelerated removal of CO intermediates (CO*). Theoretical calculations and CO stripping experiments demonstrate that the FCC-Pt₃Sn INTNWs lower the energy barrier for converting CO* into COOH* by reducing CO* binding and enhancing OH adsorption, thus significantly improving the MOR activity, CO tolerance, and stability.

The reactive oxygen species (ROS) generation from photosensitizer in photodynamic therapy (PDT) is limited by tumor hypoxia. Even type-I photosensitizers, e.g., sulfur-substituted Nile blue, still rely on oxygen as the main center for transferring electrons to generate ROS. Cutting off the pathway of oxygen consumption in tumor can help photosensitizers overcome the limitation of low oxygen, in order to efficiently generate more ROS. It is known that glycolysis inhibitor 3-bromopyruvic acid (3-BP), which could specially target mitochondria, can provide more oxygen by inhibiting oxidative phosphorylation. Herein, we successfully designed and synthesized a new 3-BP-coupled sulfur-substituted Nile blue as prodrug (NBBP) for chemical/photodynamic synergistic therapy. Major results indicated that the protons in tumor catalyzed the hydrolysis of NBBP, inhibited photoinduced electron transfer between 3-BP and the photosensitizer in NBBP and further assisted the photosensitizer to be localized in mitochondria, utilizing local oxygen as much as possible and kill tumor cells more efficiently. Moreover, the glycolysis inhibition-induced autophagy was combined with PDT-induced autophagy, which could promote the deaths of tumor cells. Unlike other remedies exploiting nanomaterials, this construction method of NBBP achieves the efficient synergy of photodynamic therapy and glycolysis inhibition, stronger than their theoretical addition, in spatiotemporal dimensions. Our study provides not only a highly efficient platform for tumor therapy but also a design approach for prodrugs with synergistic effects.

Seawater electrolysis for green hydrogen production is one of the key technologies for achieving carbon neutrality. However, in anode systems, the chloride ions (Cl⁻) in seawater will trigger an undesired chlorine evolution reaction (CER) that competes with an oxygen evolution reaction (OER), resulting in inferior OER activity and selectivity. Besides, the corrosive Cl⁻ and its derivative products will corrode anodes during seawater electrolysis, leading to poor stability. Therefore, great efforts have been devoted to developing efficient strategies for chlorine inhibition to improve the activity, selectivity, and stability of anode materials. Herein, focusing on chlorine inhibition, we present a mini review to comprehensively and concisely summarize the recent progress in anode systems for boosting seawater electrolysis. In particular, two strategies of physical and chemical regulation to inhibit Cl⁻ are summarized in some representative cases. Finally, some challenges and future opportunities in anode systems for seawater electrolysis are prospected. This mini review aims to shed light on designing highly efficient anode materials for seawater electrolysis.

Realizing simultaneous adjustment of energy levels and work functions in two-dimensional/three-dimensional (2D/3D) perovskite solar cells (PSCs) is a challenge. Here, a pseudohalide 3,5-bis (trifluoromethyl) benzylammonium tetrafluoroborate (TF-PMABF₄) was used to react with unreacted PbI₂ on the surface of 3D bulky perovskite to form a mixed halide of 2D perovskite denoted (TF-PMA)₂FA₂Pb₃I₈(BF₄)₂. This novel 2D/3D perovskite enables the simultaneous adjustment of energy levels and work functions on the surface of active layers. Due to the significantly enhanced quality of 2D/3D perovskite film, decreased surface defects and increased charge carrier lifetime, the 2D/3D PSCs exhibit an outstanding power conversion efficiency (PCE) of 25.15% and a high V_OC of 1.194 V. Importantly, 2D/3D PSCs exhibit remarkable enhancements in environmental stability, unencapsulated devices retaining more than 90% of their initial PCE at 50% humidity for 2,280 h.

Unveiling the role of weak non-covalent forces in chiral self-assembly is pivotal in the design and fabrication of functional chiroptical materials. The nature of arene-perfluoroarene (AP) force is the electrostatic attraction between π-hole and π planes of perfluoroarenes and polyaromatic hydrocarbons (PAHs), which is emerging in constructing supramolecular motifs and coassembled optical devices. In this work, we reveal the potential of AP forces in building diversified levels of chiral coassemblies adaptive to the geometries of PAHs. The naphthalene-F₈ was covalently conjugated with a chiral amine, which folded into a semi-rectangular geometry via two intramolecular F⋯H bonds. PAHs of naphthalene, anthracene, pyrene, carbazole, perylene and benzoperylene were introduced to afford coassemblies in the crystalline state. X-ray structures suggest the formation of supramolecular boxes that encapsulate the PAHs with a 2:1 stoichiometric ratio, as well as the formation of consecutive layered ladders with a 1:1 stoichiometric ratio. The preference is adaptive to the geometries of PAHs, and experimental and computational results evidenced the ladder structures possess strong binding affinity. On this top, the selective chiral recognition in the mixtures of PAHs was realized, which shows promising applications in the separation of PAHs and rational design of crystalline chiroptical materials.

The efficient harvesting of triplet excitons is crucial to the realization of high-performance organic light-emitting diodes (OLEDs). Herein, we show that coordination of donor-acceptor (D-A) type molecules to a metal atom in a monodentate fashion can lead to thermally activated delayed fluorescence (TADF) emissions with wide color tunability only through varying the non-coordinating acceptor moiety. A panel of TADF gold(I) complexes with emission maxima (λ_max) of 545–645 nm from metal perturbed intraligand charge-transfer (MPICT) excited states have been developed. Synergetic effects of heavy atom-induced spin-orbit coupling (SOC), steric-induced donor-acceptor twisting and suppressed intramolecular motions lead to high emission efficiencies of 65%–85% in doped films with delayed fluorescence lifetime of as short as 2.0 µs. Transient absorption spectroscopic studies on selected complexes determined the k_ISC to be 6.5 × 10⁹ s⁻¹. Theoretical calculations confirmed the participation of minor d orbital into the lowest excited state, which led to an SOC value of 5.19 cm⁻¹ between the lowest-lying singlet and triplet excited states. The yellow to deep red solution-processed OLEDs based on the new gold(I) complexes incorporated with various D-A ligands demonstrated promising performances. This study validates a modular design for TADF metal complexes, which will broaden the choices of metal centers and allow for facile color tuning via simple ligand synthesis.