Electrokinetic Analyses Uncover the Rate-Determining Step of Biomass-Derived Monosaccharide Electroreduction on Copper.

Electrochemical biomass conversion holds promise to upcycle carbon sources and produce valuable products while reducing greenhouse gas emissions. To this end, deep insight into the interfacial mechanism is essential for the rational design of an efficient electrocatalytic route, which is still an area of active research and development. Herein, we report the reduction of dihydroxyacetone (DHA)-the simplest monosaccharide derived from glycerol feedstock-to acetol, the vital chemical intermediate in industries, with faradaic efficiency of 85±5 % on a polycrystalline Cu electrode. DHA reduction follows preceding dehydration by coordination with the carbonyl and hydroxyl groups and the subsequent hydrogenation. The electrokinetic profile indicates that the rate-determining step (RDS) includes a proton-coupled electron transfer (PCET) to the dehydrated intermediate, revealed by coverage-dependent Tafel slope and isotopic labeling experiments. An approximate zero-order dependence of H+ suggests that water acts as the proton donor for the interfacial PCET process. Leveraging these insights, we formulate microkinetic models to illustrate its origin that Eley-Rideal (E-R) dominates over Langmuir-Hinshelwood (L-H) in governing Cu-mediated DHA reduction, offering rational guidance that increasing the concentration of the adsorbed reactant alone would be sufficient to promote the activity in designing practical catalysts.

Defects in lead halide perovskite light-emitting diodes under electric field: from behavior to passivation strategies.

Lead halide perovskites (LHPs) are emerging semiconductor materials for light-emitting diodes (LEDs) owing to their unique structure and superior optoelectronic properties. However, defects that initiate degradation of LHPs through external stimuli and prompt internal ion migration at the interfaces remain a significant challenge. The electric field (EF), which is a fundamental driving force in LED operation, complicates the role of these defects in the physical and chemical properties of LHPs. A deeper understanding of EF-induced defect behavior is crucial for optimizing the LED performance. In this review, the origins and characterization of defects are explored, indicating the influence of EF-induced defect dynamics on LED performance and stability. A comprehensive overview of recent defect passivation approaches for LHP bulk films and nanocrystals (NCs) is also provided. Given the ubiquity of EF, a summary of the EF-induced defect behavior can enhance the performance of perovskite LEDs and related optoelectronic devices.

Branched-Chain-Induced Host-Guest Assembly in Covalent-Organic Frameworks for Efficient Separation of No-Carrier-Added 177Lu.

No-carrier-added (NCA) 177Lu is one of the most interesting nuclides for endoradiotherapy. With the dramatically rapid development of radiopharmaceutical and nuclear medicine, there is a sharp increase in the radionuclide supply of NCA 177Lu, which has formed a great challenge to current radiochemical separation constituted on classical materials. Hence, it is of vital importance to design and prepare new functional materials able of recovering 177Lu from an irradiated target with excellent efficacy. In this work, we proposed to apply noncovalent interactions to regulate the porous properties of covalent organic frameworks (COFs) by tuning the branched chain, rendering related covalent hosts different encapsulation abilities toward a flexible guest, 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (P507). More interestingly, we found that the noncovalent interaction has a great effect on the host-guest complexes, which can achieve efficient NCA 177Lu separation with high recovery (95.97%). A systematic mechanism combined with experimental and theoretical investigations has confirmed that the noncovalent interactions between COFs and P507 play a preeminent role in adjusting the macroscopic properties of the host-guest complexes. This work not only uncovers that noncovalent interactions can affect the basic properties of covalent organic bonded materials but also provides a strategy for the design and preparation of other new moieties with specific functionalities.

Streptomyces kalpinensis sp. nov., an actinomycete isolated from a salt water beach.

A novel actinobacterium designated TRM 46509T was isolated from a salt water beach at Kalpin, Xinjiang, north-west China. The strain was aerobic and Gram-stain-positive, with an optimum NaCl concentration for growth of 1 % (w/v). The isolate formed sparse aerial mycelium and produced spiral spores at the end of the aerial mycelium on Gauze's No. 1 medium. The isolate contained ll-diaminopimelic acid as the diagnostic diamino acid and ribose as the major whole-cell sugar. The polar lipids included diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, phosphatidylinositol, phosphatidylinositol mannosides and an unidentified phospholipid. The predominant menaquinones were MK-9(H2), MK-9(H6) and MK-9(H8). The major fatty acids were C16:0, iso-C16 : 0, anteiso-C15 : 0, iso-C15 : 0 and iso-C14 : 0. The G+C content of the DNA was 69.3 mol%. Phylogenetic analysis showed that strain TRM 46509T shared 16S rRNA gene sequence similarity of 97.6 % with the closest described species Streptomyces tacrolimicus ATCC 55098T. On the basis of evidence from this polyphasic study, strain TRM 46509T should be designated as representing a novel species of the genus Streptomyces, for which the name Streptomyces kalpinensis sp. nov. is proposed. The type strain is TRM 46509T (=CCTCC AA 2015028T=KCTC 39667T).

Streptomyces litoralis sp. nov., isolated from a salt water beach.

A novel actinomycete strain, designated TRM 46515T, was isolated from a salt water beach at Awat, Xinjiang, Northwest China, and characterized using polyphasic taxonomy. Comparison of 16S rRNA gene sequences showed that strain TRM 46515T is a member of the genus Streptomyces, exhibiting highest similarity with Streptomyces qinglanensis 172205T (98.32 %). However, DNA-DNA relatedness and phenotypic data readily distinguished strain TRM 46515T from phylogenetically related type strains. The G+C content of the DNA was 70.40 mol%. Whole-cell hydrolysates of strain TRM 46515T were found to contain ll-diaminopimelic acid as the diagnostic diamino acid and ribose was the major whole-cell sugar. The major fatty acids identified were anteiso-C17 : 0, anteiso-C15 : 0, iso-C15 : 0, iso-C16 : 0 and iso-C17 : 0. The main menaquinone was MK-9(H8) and the polar lipids were identified as diphosphatidylglycerol, phosphatidyl ethanolamine, phosphatidylglycerol, phosphatidylcholine, phosphatidylinositol and one unknown glycolipid. On the basis of these phenotypic, chemotaxonomic and phylogenetic data, strain TRM 46515T should be designated as a representative of a novel species of the genus Streptomyces, for which the name Streptomyces litoralis sp. nov. is proposed. The type strain is TRM 46515T (=CCTCC AA 2015040T=KCTC 39729T).