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Optically pumped gas molecular terahertz (THz) lasers are promising for generating high-power and high-beam-quality coherent THz radiation. However, for pulsed gas THz lasers, the temporal behavior of the output THz pulse has rarely been investigated. In this study, the temporal behavior of a pulsed gas THz pumped by a fundamental-mode TEA CO

Poor charge separation is the main factor that limits the photocatalytic hydrogen generation efficiency of organic conjugated polymers. In this work, a series of linear donor–acceptor (D–A) type oligomers are synthesized by a palladium-catalyzed Sonogashira–Hagihara coupling of electron-deficient diborane unit and different dihalide substitution sulfur functionalized monomers. Such diborane-based A unit exerts great impact on the resulting oligomers, including distinct semiconductor characters with isolated lowest unoccupied molecular orbital (LUMO) orbits locating in diborane-containing fragment, and elevated LUMO level higher than water reduction potential. Relative to A-A type counterpart, the enhanced dipole polarization effect in D–A oligomers facilitates separation of photogenerated charge carriers, as evidenced by notably prolonged electron lifetime. Owing to π–π stacking of rigid backbone, the oligomers can aggregate into an interesting 2D semicrystalline nanosheet (≈2.74 nm), which is rarely reported in linear polymeric photocatalysts prepared by similar carbon–carbon coupling reaction. Despite low surface area (30.3 m2 g−1), such ultrathin nanosheet D–A oligomer offers outstanding visible light (λ > 420 nm) hydrogen evolution rate of 833 µmol g−1 h−1, 14 times greater than its A-A analogue (61 µmol g−1 h−1). The study highlights the great potential of using boron element to construct D–A type oligomers for efficient photocatalytic hydrogen generation. © 2021 Wiley-VCH GmbH

Inspired by amino acids with amphoteric groups for electrochemical enantiorecognition, amphoteric chitosan (ACCS) was prepared with chloroacetic acid and CS, and has perfect solubility in alkaline and acid solution, compared with CS. ACCS was linked to the ethylenediamine-functionalized multiwalled carbon nanotubes (MWCNTs–EA) through covalent bonding. Chiral interfaces were fabricated with MWCNTs–EA–ACCS and used for the electrochemical enantiorecognition of phenylalanine (Phe) enantiomers. The ACCS chiral interfaces showed excellent selectivity toward the Phe enantiomers. Also, the optimization of parameters such as pH, temperature and response time was carried out for the electrochemical recognition. Furthermore, the ACCS is capable of determining the percentage of enantiomers in mixed solutions. The electrochemical recognition of amino acid enantiomers with different functional groups was investigated, and it was found that the amphoteric functional groups of ACCS play an important role in the enantioselective discrimination.

A simple chiral electrochemical sensor based on N-carboxymethyl chitosan (NCCS) covalently bound with ethylenediamine-carboxylic multiwalled carbon nanotubes (MWCNTs-EA) was developed for enantioselective recognition of tryptophan (Trp) enantiomers; NCCS preferably combined with L-Trp than with D-Trp. The recognition efficiency prominently increased after the introduction of N-carboxymethyl into chitosan (CS). The carboxymethyl and imino groups of NCCS play an important role in enantioselective discrimination system. Moreover, the parameters of enantioselective recognition such as pH, temperature and response time were investigated. The electrochemical recognition of amino acid enantiomers with different functional groups was carried out. The chiral recognition mechanism was investigated by quantum computing. The results were confirmed by quantum chemical calculations.