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Bismuth vanadate (BiVO4) is a promising photocatalytic material for use in environmental protection and water splitting. However, its short photogenerated carrier lifetime and narrow visible-light response restrict its extensive application. Herein, a novel electrospinning method was developed to prepare bismuth (Bi)-modified BiVO4 (Bi/BiVO4) porous nanofibers. The morphologies, structures, and chemical states of the obtained samples were characterized using a series of analytical techniques. The photocatalytic performance of the Bi/BiVO4 porous nanofibers was evaluated via the photocatalytic degradation of methylene blue (MB) under visible-light irradiation. The enhanced visible-light photocatalytic activity of Bi/BiVO4 can be attributed to the Bi nanoparticles, which exhibit a surface plasmon resonance (SPR) effect and have semiconductor character, extending the optical absorption of BiVO4 and restraining the recombination of electron–hole pairs during the photocatalytic degradation process, respectively. In this work, new insight is provided into the fabrication of a Bi/BiVO4 composite, which can act as an outstanding visible-light responsive photocatalyst, facilitating its application in the field of environmental protection. [ABSTRACT FROM AUTHOR]

In this paper, we propose a new acetylenic carbon material called pyridyne, which is composed of acetylenic linkages and pyridine rings. From first-principles calculations, we investigate the structural, elastic and electronic properties of pyridyne. It is found that the structure of pyridyne is stable at 300 K and its stability is comparable to experimentally synthesized graphdiyne and graphtetrayne. Compared with graphene or graphyne, pyridyne possesses more diverse pores and reduced delocalization of electrons. The in-plane stiffness of pyridyne is 183 N m−1 with a Poisson's ratio of 0.304. Pyridyne is found to be a semiconductor with a direct band gap of 0.91 eV. The intrinsic electron mobility can reach 6.08 × 104 cm2 V−1 s−1, while the hole mobility can reach 1.82 × 104 cm2 V−1 s−1. [ABSTRACT FROM AUTHOR]

Ni-based heterostructures have been regarded as promising catalysts for the hydrogen evolution reaction (HER) in alkaline solutions due to its high efficiency in catalyzing the water dissociation process. Therefore, an in-depth understanding of the water-dissociation-related activity of Ni species within varied structures and coordination environments is significant for the design of novel catalysts. Herein, we synthesized three types of Ni-based heterostructures, namely NiS/MoS2, NiSe/MoS2 and NiSe2/MoS2 by a controllable route to investigate their catalytic trends and origins of the HER under alkaline conditions. Combined with experimental data and theoretical calculation results, we revealed that the alkaline HER activity of the heterostructures relies on the catalyzing ability of Ni species in the Volmer step, which is associated with the d-band center, and is further related to the coordination condition of the Ni atoms in the chalcogenides. With the highest valence state and d-band center among the samples, Ni atoms in NiS exhibit the fastest reaction rate in the Volmer step, thus providing the best catalytic activity for the NiS/MoS2 heterostructure in the alkaline HER. Furthermore, an activity trend for the Ni chalcogenides in the Volmer step, in the order of NiS > NiSe2 > NiSe, has been proposed, which is expected to contribute insights into the design of novel heterostructured catalysts. [ABSTRACT FROM AUTHOR]

Carbon quantum dots/TiO2 nanotubes composites were prepared by a simple technical route through which TiO2 nanotubes prepared by electrospinning were dispersed in carbon quantum dots solution, and dried at 80 °C. The results indicated that the TiO2 nanotubes composites were combined with the carbon quantum dots. The photocatalytic activity of the carbon quantum dots/TiO2 nanotubes composites was investigated by the degradation of rhodamine B under visible light irradiation, and it was demonstrated to be significantly enhanced compared with that of pure TiO2 nanotubes. Through analysis, this enhancement of visible light photocatalytic activity was attributed to the carbon quantum dots with the unique up-converted photoluminescence behavior. [ABSTRACT FROM AUTHOR]

Water-soluble, fluorescent carbon dots (CDs) have been successfully synthesized from waste paper. The as-prepared CDs, with an amorphous structure and small particle size, exhibit good photostability, high photoluminescence quantum yields (PLQYs) and fairly low toxicity, which indicate potential applications in the field of biolabelling. [ABSTRACT FROM AUTHOR]