Science China Chemistry最新文献

Dry-coating electrode fabrication technologies have emerged as a promising solution for green and low-cost battery manufacturing, which can eliminate the use of contaminative and toxic solvents that challenge current battery industry. The key challenges of current dry-coating electrode fabrication lie in the uneven dispersion of various components and limited scalability. In this review, we introduce the fundamental mechanisms and recent advances in dry-coating electrode fabrication technologies, with a focus on key strategies for material design and process optimization that can promote structural integrity and electrochemical performance of the dry-coating electrodes. We also discuss the effectiveness of these innovative approaches towards promoted processing and scalability. In addition, several solutions regarding inorganic additives, composite binders, and low-melting-point additives are further introduced, which shows promise to address the component agglomeration and interface adhesion. Moreover, we prospect the deployment of dry-coating electrode fabrication technologies in solid-state batteries and conversion-type batteries, where the solvent-free nature and interfacial compatibility offer appealing benefits. The current challenges and future opportunities for dry-coating electrode fabrication technologies are summarized, aiming to provide valuable insights to this emerging field.

Developing safe and high-performance solid polymer electrolytes (SPEs) remains a critical challenge for all-solid-state batteries. Among various polymer materials, poly(ethylene oxide) (PEO) is most widely studied, while poly(vinylidene fluoride) (PVDF) has also attracted great interest recently. However, the intrinsic disadvantages of single polymers make them hardly meet the demands for practical applications. Physical blending of different types of SPEs is a simple and straightforward strategy to optimize their performance. Unfortunately, the direct blending of PEO and PVDF (or PVDF derivatives) usually leads to macro-phase separation and fails to couple together. Herein, we designed and synthesized PEO-based block copolymers as compatibilizers to prevent macroscopic phase separation in PVDF/PEO blends. By tuning the interfacial compatibility, continuous nanostructures with high optical transparency are constructed through the microphase segregation. The obtained SPEs combine the merits of high mechanical modulus (380 MPa), high ionic conductivity (2.0 × 10⁻⁴ S cm⁻¹, 30 °C), large transference number (0.60), and electrochemical stability (4.5 V). This simple and efficient chemical modification approach sheds light on alternative solutions for designing high-performance SPEs.

The electrochemical oxidation of 5-hydroxymethylfurfural (HMFOR) represents a promising route for biomass valorization, yet its efficiency is often limited by suboptimal adsorption configurations of reaction intermediates on conventional catalysts. Herein, we demonstrate that Ce doping effectively modulates both geometric and electronic structures of CuO to achieve exceptional HMFOR performance. The designed Ce-CuO catalyst exhibits remarkable activity and selectivity, achieving near-quantitative FDCA Faradaic efficiency (98.4%) with substantially enhanced production rates (67.0 µmol cm⁻² h⁻¹) compared to pristine CuO (87.3%, 54.0 µmol cm⁻² h⁻¹), while maintaining over 90% FDCA Faradaic efficiency over 8 cycles. Comprehensive in-situ/ex-situ spectroscopic characterization and theoretical calculations reveal that Ce incorporation induces electron transfer to Cu sites and triggers the coordination geometric restructuring, while simultaneously optimizing the geometric matching between active sites and reaction intermediates. This dual modulation enables key intermediates to adopt thermodynamically favorable adsorption configurations with significantly reduced steric hindrance, thereby lowering the energy barrier of the rate-determining step from 0.99 to 0.46 eV. This work establishes geometric configuration engineering through rational dopant incorporation as a crucial design strategy beyond conventional electronic structure modulation for advanced electrocatalysts in biomass conversion and other complex electrochemical transformations.

The primary amino acid sequence dictates the structural, conformational and functional properties of proteins. Extending this sequence-function paradigm to synthetic self-assemblies provides a powerful means to program molecular structure and emergent properties with precision. Here, we report the remote control of both the stereoselective synthesis and functional properties of molecular cinquefoil knots by modification of the peptide sequence attached to the knotted loop. Specifically, six dipeptide chains, containing alanine (Ala), valine (Val) or phenylalanine (Phe) units, are incorporated directly into the ligand backbone at sites peripheral to the knotted core. Using a metal-templated approach followed by ring-closing metathesis, distinct knotted architectures were prepared with high efficiency (58%–95%) and complete stereoselectivity. Advanced NMR analyses confirmed that subtle sequence variations influence local conformational preferences without altering topological integrity. Heterogeneous peptide helicates display rapid exchange in self-sorting compared with their homogeneous counterparts, owing to steric and cooperative mismatches, resulting in reduced stability, reminiscent of sequence-dependent stabilization in protein folding and assembly. Circular dichroism studies demonstrated that global topology dominates the chiroptical response, with minor modulation from residue placement. UV-vis titrations revealed strong bromide binding (K_a > 10⁵ M⁻¹), with sequence-specific variations in affinity, highlighting the role of residue identity and position in modulating molecular recognition. Incorporation of a tripeptide sequence further demonstrated the broad applicability of the strategy. These results establish a general strategy for encoding functional information in molecular knots through peripheral amino acid sequences, providing a biomimetic means of remotely controlling the functions of topologically complex molecular architectures.

Photocatalysis provides a green way to produce hydrogen peroxide (H₂O₂) from oxygen and water. Although many materials with different structures have been designed for the photocatalytic production of H₂O₂, the supramolecular porous materials have been rarely reported. Herein, three imine-linked [3+6] type POCs, containing benzoxadiazole units with tunable functional groups (R = H, OMe, OH), named H-POC, OMe-POC, and OH-POC, are rationally fabricated for visible-light-driven generation of H₂O₂ in water and oxygen. The results show that performance is improved by regulating group from H, OMe, to OH, with the H₂O₂ yields of 527, 670, and 976 µmol h⁻¹ g⁻¹, respectively. Moreover, under the synergistic effect of light and heat (70 °C), the H₂O₂ production rate of OH-POC was further increased to 2748 µmol h⁻¹ g⁻¹. Photophysical and electrochemical studies have shown that functional group regulation enhances hydrophilicity, light absorption, and charge separation/transfer. In addition, the mechanism of the two-step 1e⁻ ORR and direct 2e⁻ WOR pathway for H₂O₂ production. Importantly, OH-POC shows extraordinary potential in the degradation of water environmental pollutants (tetracycline hydrochloride and mercaptobenzothiazole). This study provides a novel idea for the rational design of photocatalysts that rely on the POCs platform from the perspective of molecular structure design.

Defect engineering is regarded as an effective strategy for enhancing gas-sensing performance in metal-organic frameworks (MOFs). However, precise control over defect types and their specific impact on gas-sensing properties remains a significant challenge. Herein, we propose a representative water-treatment approach to induce and regulate different defect types in various MOFs. Comparative structural analysis of ZIF-8 and ZIF-67, differing in metal centers, before and after water treatment, reveals that water molecules disrupt metal-ligand bonds, leading to metal defects in ZIF-8 via metal detachment and ligand defects in ZIF-67 through partial ligand loss. Gas-sensing results demonstrate that defect concentrations and gas-sensing capabilities in MOFs can be effectively modulated by controlling water treatment time. Notably, the presence of metal defects enhances the NO₂ response of ZIF-8 (20 ppm) by 2.63 times, while ligand defects improve the C₂H₄ response of ZIF-67 (25 ppm) by 3.96 times. Additionally, metal defect formation in MOF-74 is evidenced by a 2.97-fold enhancement in its response to 100 ppm acetone. Density functional theory calculations confirm that the defect sites enhance gas adsorption and sensing performance. This study offers new insights into defect engineering in MOFs, expanding the potential of defect-engineered MOFs for diverse applications.

As important catalysts for C–C coupling, copper-based materials have great potential for electrocatalytic reduction of CO₂ to C₂₊ products. In this work, Cu₂O catalysts modified with different lanthanide hydroxides were successfully synthesized and used for CO₂ electroreduction. The results showed that compared with Cu₂O/Gd(OH)₃ and Cu₂O/Yb(OH)₃ catalysts, Cu₂O/La(OH)₃ exhibited the highest electrocatalytic performance for CO₂ reduction. This catalyst was able to maintain a high Faraday efficiency for C₂₊ products (({rm FE}_{{rm C}_{2+}})) of about 60% within the current density range of 400–800 mA cm⁻². The highest ({rm FE}_{{rm C}_{2+}}) reached 66% at 600 mA cm⁻² and the partial current density for C₂₊ products reached a maximum of 488 mA cm⁻². Meanwhile, the catalyst could run stably for 40 h with a remained ({rm FE}_{{rm C}_{2+}}) of about 60%. Multiple characterizations reveal that the introduction of La(OH)₃ promotes the formation of *CO intermediates, and also helps to stabilize the Cu(I) species in Cu₂O under cathodic potentials, thus facilitating the C–C coupling for C₂₊ production. This work provides a new strategy to enhance the C₂₊ production via stabilizing Cu(I).