Science China Chemistry最新文献

Establishing supply chains for future ammonia energy systems requires the development of efficient materials and processes for ammonia production under mild conditions. Recent researches disclose unique functionalities of binary alkali and alkaline earth metal hydrides in mediating ammonia synthesis. Thanks to the rich compositional and structural properties of the metal-hydrogen system, we herein report that LiBaH₃, as a narrow band gap perovskite hydride, exhibits a strong response to visible light illumination. Specifically, hydridic hydrogen undergoes reductive elimination of producing H₂ and creates an electron-rich surface. Such an environment favors dinitrogen fixation to form N–H bonds. Based on this chemical property, a chemical looping ammonia synthesis process mediated by LiBaH₃ and driven by both photo and thermal energies was proposed and evaluated. This work demonstrates that hydride perovskites are promising candidates for mediating photo-assisted nitrogen fixation reactions.

Metal-organic frameworks (MOFs) based on anion exchange membranes (AEMs) have garnered considerable interest, particularly for their potential to enhance ion conductivity by pre-introducing anions into MOFs. This approach is recognized as straightforward and effective for improving ion conductivity. However, developing high-performance AEMs is limited by the inherent instability and low resistance of MOFs. This study presents a novel 1,3,5-triazine μ₃-bridged neutral Cu(I) framework, designated SXU-120 (where SXU represents Shanxi University). This framework is synthesized using melamine, a widely available industrial product, as the starting material, achieving a high space-time yield exceeding 1.1 kg m⁻³ day⁻¹. The organic ligands and metal ions in SXU-120 are 3-connected, forming a rare eta topology with the point symbol 8³. SXU-120 exhibits exceptional stability, even in a 10 M KOH solution, due to its high density of uncoordinated–NH₂ and carbonyl groups. Furthermore, the framework’s unique one-dimensional channels, characterized by their electronegativity, interact electrostatically with OH⁻ ions, thereby accelerating OH⁻ ion transfer along these channels. Consequently, the OH⁻ conductivity of this material reaches an impressive 0.49 S cm⁻¹ at 90 °C under full humidity for 100 h, representing the highest OH⁻ conductivity reported for MOF-based conductors to date. These properties make SXU-120 a promising candidate for efficient AEM materials in next generation industrial applications.

Hepatocellular carcinoma (HCC) is a highly aggressive liver malignancy and the main form of liver cancer. Early diagnosis and treatment of HCC can effectively reduce mortality. Carboxylesterase (CE)-specific detection and imaging can be used for early diagnosis and image-guided surgical of HCC. However, traditional optical probes suffer from poor selectivity and low imaging signal-to-noise ratio. Here, we have constructed a series of chemiluminescent probes for carboxylesterase detection based on the strategy of enzymatic pocket-oriented steric tailoring techniques. The probes with different unique and excellent properties have been obtained through the structure-based steric hindrance adjustment on the recognition site. Here, CE-2 has been successfully used for high-throughput screening of rapid carboxylesterase inhibitors due to its extremely low detection limit (2.5 × 10⁻⁴ U mL⁻¹) and fast recognition ability. CE-3 has been successfully used for image-guided surgery of orthotopic hepatocellular carcinoma due to its ultra-long chemiluminescence imaging (over 12 h) of hepatocellular carcinoma. This study may promote advances in the rapid detection and screening of inhibitory drugs for CE and the field of surgical navigation in HCC.

Modifying the microstructure of photocatalysts while simultaneously introducing vacancies has shown significant potential in enhancing their performance for hydrogen production. Herein, a novel tubular mesoporous carbon nitride (TMCN) with nitrogen vacancies was fabricated using a microwave-assisted synthesis strategy, employing melamine-cyanuric acid supramolecular (MC-S) as the precursor. The optimized TMCN exhibited an outstanding H₂ production rate, approximately 29 times higher than that of pristine g-C₃N₄. The N-vacancies serve as sites for reactant adsorption and activation, leading to enhanced delocalization of HOMO-LUMO. Furthermore, the porous structures of TMCN facilitate the reactant diffusion, while its tubular architectures promote the oriented transfer of charge carriers. Crucially, the markedly improved photocatalytic performance of TMCN can be predominantly attributed to the synergistic effects arising from its superior structure and N-vacancy defects. This work opens new possibilities for the simultaneous formation of surface defect states as photocatalytic reaction sites and distinctive structures conducive to charge carrier transport.

Lipid nanoparticles (LNPs) are non-viral nucleic acid delivery systems that show great potential in vaccine development and disease treatment. Although LNPs are particularly advantageous for in vivo delivery, the wide application of LNPs is impeded as their systemic delivery of nucleic acid drugs to extrahepatic tissues remains highly challenging. To address this issue, we developed lung-targeted polyzwitterionic LNPs with zwitterionic polymer poly(2-methyacryloyloxyethyl phosphorylcholine) (PMPC) modified 1,2-dimyristoyl-sn-glycerol lipid for the delivery of small interfering RNA (siRNA). Three libraries with 90 PMPC-LNPs@siRNA were established. The polyzwitterionic PMPC-LNPs had high siRNA encapsulation efficiency of about 90%. The findings revealed that polyzwitterionic PMPC-LNPs@siRNA absorbed protein corona with the main component of Vitronectin, mediating lung-targeted delivery of siRNA. With good cellular uptake and endo/lysosomal escape ability, in vitro and in vivo studies demonstrated that polyzwitterionic PMPC-LNPs with siRNA against tumor necrosis factor-α (TNF-α) could significantly down-regulate the TNF-α in mRNA and protein levels, and improved the pathological features of lung inflammation. Polyzwitterionic PMPC-LNPs@siRNA achieved safe and efficient treatment of lung inflammation. Therefore, this work offered a promising siRNA therapeutic approach for lung diseases.

The conventional method of fabricating hydrogels constantly confronts the conflict between elasticity and toughness, limiting their repetitive application. Achieving the desired elasticity through a simple and low-cost approach is a significant challenge for hydrogels, particularly through rational molecular design. Here, low-hysteresis and high-toughness hydrogels are developed from the design of a new feature monomer, N-acryloylethylsemicarbazide (NACE). Based on a concept of “asymmetric H-bonding design”, the unique double and triple H-bonding of NACE can result in a novel asymmetric crosslinking polymer with alternating strong and weak H-bonding regions. The NACE is copolymerized with acrylamide (AM) to regulate the mechanical properties of hydrogel via H-bonding density. The P(NACE-AM) ionic hydrogels are obtained simply and rapidly via one-step photopolymerization without a chemical cross-linking agent. The P(NACE-AM) hydrogels combine superb mechanical elasticity and toughness, and excellent ionic conductivity, showing great potential as durable ionic conductive devices for wearable utilization.

Large-area flexible organic photovoltaic (OPV) modules are challenging to achieve high power conversion efficiency (PCE). Electrical shunts or shortages generally occur in large-area OPV modules due to the ultrathin (100–200 nm) and soft active layers. Improving the surface smoothness of bottom transparent electrode will be able to suppress the shunts and shortages. In this work, we report a method to fabricate smooth and flexible transparent electrodes based on thin silver film, and further to fabricate efficient large-area flexible OPV modules. The fabricated thin silver transparent electrodes simultaneously have high conductivity, high optical transmittance, good mechanical flexibility and low surface roughness. Humidity exposure (h.e.) treatment on MoO₃ effectively facilitates the continuous growth of the thin transparent silver electrode. 6 nm silver film on MoO₃ (h.e.) on plastic substrate shows a transmittance up to 89%, a sheet resistance of 15 Ω/sq, and a low surface roughness with a root-mean-square value of 0.276 nm. Furthermore, 52-cm² flexible organic solar modules (15 subcells) showed a certified PCE of 12.66%. Furthermore, a 1350 cm² flexible component assembled by 25 pieces of 52–55 cm² modules showed certified PCE of 12.10% with an open-circuit voltage of 62.85 V.