Chemistry of Materials最新文献

Designing the organization of supramolecular systemswith high-precisionself-assembly along diverse pathways is a crucial strategy for optimizingfunctional properties. However, achieving such control remains a significantchallenge in the field. Here, we report the selective pathway dynamicsof platinum(II) terpyridine-based complexes with (R)-chiral side chains, which exhibit three distinct states (Agg-A,-DH, and -SH) in different pathways during the self-assembly process.The assembly is initiated by the formation of metastable helical structures(Agg-A) with concentration-dependent handedness, which subsequentlyundergo a transient helical inversion. Kinetic evaluations revealthat Agg-A diverges into two distinct pathways governed by the thermalenergy landscape. At 308 K, Agg-A acts as an on-pathway intermediate,forming a kinetically trapped superhelix (Agg-DH) via interfiber interactions.Conversely, at 333 K, Agg-A serves as an off-pathway intermediate,directly transforming into a thermodynamically stable single helix(Agg-SH). Ultimately, all metastable and kinetically trapped statesconverge toward the thermodynamically favored Agg-SH. Notably, thisstructural divergence enables the selective regulation of chiropticalfunctions. Specifically, the thermodynamically stable Agg-SH stateexhibits a distinct circularly polarized luminescence (CPL) signal,whereas the kinetically trapped Agg-DH state displays a negligibleCPL response. Furthermore, we successfully demonstrated precise pathwaycontrol utilizing seeded living supramolecular polymerization. Thisstudy highlights how morphological evolution driven by transient helicalinversion and intermolecular Pt–Pt interactions can be utilizedas a rational design strategy to program the specific optical functionsof chiral supramolecular materials.

Thephotocatalytic carbon dioxide reduction reaction (CO₂RR)offers a promising route to convert waste CO₂ intovaluable synthetic fuels and chemicals using solar energy. However,practical application is hindered by insufficient charge separation,weak CO₂ activation, and poor catalyst recoverability.Herein, we systematically synthesized a self-sufficient photocatalystcomprising ionic liquid (IL)-modified Pt single atoms on TiO₂ nanosheets, fabricated in both powder (IL-Pt/TiO₂) and3D-printed monolithic (3D-IL-Pt/TiO₂) forms. In the photocatalyticCO₂RR, the 3D-IL-Pt/TiO₂ exhibits a significantlyenhanced CO evolution rate of 2051.46 μmol g^–1 h^–1, significantly higher than that of the powdersample (1598.79 μmol g^–1 h^–1) and far exceeding the sum of the individual constituents withoutadditional cocatalysts. The spectroscopic analysis reveals that whilethe IL alone does not perturb the TiO₂ lattice, its combinationwith atomically dispersed Pt induces a strong interfacial electronicredistribution. This synergistic interaction of IL and Pt atoms stabilizessurface Ti³⁺ species and electron-rich Pt sites and modifiesthe surface oxygen environment without degrading the bulk structureof TiO₂. Notably, the system functions most effectivelywithout external photosensitizers, which otherwise compete for lightabsorption and promote charge recombination. Long-term stability testsreveal that the 3D-printed monolith retained stable performance overextended cycling, whereas the powder material gradually deactivated.These findings demonstrate that optimized interfacial electronic regulation,rather than extreme band-edge position, governs photocatalytic efficiency,offering a strategy for scalable solar-driven CO₂ conversion.

Therising consideration of ammonia as a viable fuelhas propelledthe research on exploring the feasibility of commercializing directammonia fuel cells (DAFCs). However, DAFCs at present have poor efficiencycaused by the sluggish ammonia oxidation reaction (AOR) kinetics andsurface poisoning of the catalyst. This work is tackling the issuesassociated with the anodic part of the DAFCs by developing an electrocatalyst,i.e., Pt_0.76Ir_0.21W_0.03/HGO-13. Theintrinsic pores of Holey Graphene Oxide (HGO) play a decisive rolein enhancing the metal–support interactions, along with effectivelymitigating flooding and mass-transport limitations during device testing.The oxyphilic W acts as a competitive OH^– reservoir,reducing OH^– poisoning on the PtIr active sites,which further boosts the AOR activity through OH^– mobilization by the spillover mechanism. The theoretical investigationof Pt_0.76Ir_0.21W_0.03/HGO-13 revealsthe electron redistribution among Pt, Ir, and W, thereby modulatingthe NH_x and N adsorption and mitigatingactive-site poisoning. Also, the 2–3 atomic % of the W incorporationcreates better nanointerface formation with PtIr than bulk W. Electrochemicalhalf-cell analysis shows a better onset potential of 0.37 V and asuperior peak current density of 76.1 A g^–1 (Pt_0.76Ir_0.21W_0.03/HGO-13) compared to thebenchmark systems (Pt/C and PtIr/C). When employed in DAFCs, the Pt_0.76Ir_0.21W_0.03/HGO-13-based electrodeexhibits a peak power density (PPD) of 90 mW cm^–2, outperforming the standard PtIr/C (54.8 mW cm^–2), clearly augmenting the synergistic modulations between the activesites and engineered porous support achieved in the present system.

In contrast to conventional inorganic laser media, organicsingle-crystal(OSC) laser media are emerging as next-generation light sources owingto their intrinsic high processability. To achieve practical OSC lasermaterials, candidate compounds must satisfy three key requirements:(1) processability, (2) crystallinity, and (3) high luminescence performance.However, fulfilling these criteria concurrently remains challenging.Processability and crystallinity are typically in a trade-off relationship,and luminescence performance is often difficult to control becauseit depends not only on molecular structure but also on the aggregationmotifs present in the crystal state. Here, we present a crystal engineeringstrategy that enables the simultaneous realization of these threeproperties in π-conjugated organic compounds. Our approach focuseson disrupting intermolecular CH−π interactions throughthe strategic introduction of methoxy substituents. Appropriate substitutionsites induce controlled disruption of CH−π contacts,promoting the formation of a rigid crystal framework while retaininghigh processability, effectively overcoming the conventional trade-offbetween these parameters. Moreover, the resulting changes in crystalpacking are accompanied by enhanced luminescence performance, includingan increased radiative decay rate. This methodology provides a molecular-designstrategy for OSC laser media integrating processability, crystallinity,and high optical performance, offering a promising route toward next-generationlaser technologies.

Metal–organic frameworks (MOFs) with excellenttwo-photonexcited fluorescence (TPEF) properties have shown great potentialin multiple fields. While numerous pressure-responsive TPEF MOFs havebeen reported, the precise modulation of their optical performancevia structural design remains a critical challenge. In this study,the impact of ligand coordination arm length on the TPEF propertiesof tetraphenylethylene-based MOFs (TPE-MOFs) was systematically explored.By designing two TPE-MOFs with varying coordination arm lengths, itwas demonstrated that LIFM-DJZ-1, based on L1 with long coordinationarms, exhibited superior PLQY and TPA action cross sections comparedto LIFM-DJZ-2 with shortened L2. Notably, pressure stimulation furtherenhanced the TPEF performance of LIFM-DJZ-1, highlighting the potentialof structural modulation in designing high-performance piezofluorochromicmaterials. This study not only offers fresh insights into the structure-propertyrelationship in TPE-MOFs but also establishes a crucial foundationand practical guideline for advancing the development of high-performanceTPE-MOF materials.

Earth-abundant transition-metalborides are promisingalternativesto noble-metal catalysts for the hydrogen evolution reaction (HER),but achieving high activity and durability under industrially relevantoperating conditions remains challenging. Herein, we develop a seriesof arc-melted solid-solution transition-metal borides, YCr_1–xMo_xB₄, YCr_1–xW_xB₄, and YMo_1–xW_xB₄ (x = 0.25, 0.5, and0.75), as robust HER electrocatalysts for acidic media. Through solid-solutionengineering, the catalytic performance of the parent borides is significantlyimproved, with each composition outperforming commercial 20 wt % Pt/Cat high current density. Notably, YCr_0.25W_0.75B₄ exhibits the best overall HER performance, requiringonly 0.449 V overpotential to reach 1000 mA/cm², comparedwith 0.742 V for 20 wt % Pt/C. The enhanced activity is further supportedby a high double-layer capacitance of 54 mF/cm², reflectingincreased electrochemically accessible surface area and abundant exposedHER-active sites. The catalyst also shows excellent acid stability,retaining 92% of its activity after 5000 cycles and 24 h of continuousoperation. Scanning electrochemical cell microscopy (SECCM) analysisreveals heterogeneous, composition-dependent local HER behavior, withYMo_0.25W_0.75B₄ exhibiting the leastnegative onset potential, followed closely by YCr_0.25W_0.75B₄, highlighting the importance of surface compositionin controlling catalytic activity. These findings establish solid-solutiontransition-metal borides as a versatile platform for designing inexpensive,durable, and high current electrocatalysts for sustainable hydrogenproduction.