Carbyne with one-dimensional sp-hybridized carbon atoms is synthesized under ambient conditions in the laboratory.

α-Ag2WO4 (AWO) has been studied extensively due to its H2 evolution and organic pollution degradation ability under the irradiation of UV light. However, the band gap of AWO is theoretically calculated to be 3.55 eV, resulting in its sluggish reaction to visible light. Herein, we demonstrated that, by using the electronic reconstruction of AWO nanorods upon a unique process of laser irradiation in liquid, these nanorods performed good visible-light photocatalytic organics degradation and H2 evolution. Using commercial AWO powders as the starting materials, we achieved the electronic reconstruction of AWO by a recrystallization of the starting powders upon laser irradiation in liquid and synthesized AWO nanorods. Due to the weak bond energy of AWO and the far from thermodynamic equilibrium process created by laser irradiation in liquid, abundant cluster distortions, especially [WO6] cluster distortions, are introduced into the crystal lattice, the defect density increases by a factor of 2.75, and uneven intermediate energy levels are inset into the band gap, resulting in a 0.44 eV decrease of the band gap, which modified the AWO itself by electronic reconstruction to be sensitive to visible light without the addition of others. Further, the first-principles calculation was carried out to clarify the electronic reconstruction of AWO, and the theoretical results confirmed the deduction based on the experimental measurements.

effect of the upper catalysts. [ 6 ] The other one is the inconvenience originating from the intricate operations to extract the catalysts for recycling. Meanwhile powder loss may take place. [ 7 ] In order to overcome these weaknesses, we consider that photocatalysts may achieve more effi cient water splitting if they are integrated onto a substrate that can fl oat on water. [ 8 ] In this case, all the photocatalysts can absorb light energy effectively and the integrated sheet can be taken out from the water by a tweezer directly for recycling. Therefore, hydrophilic and low-mass carbon foam (CF) with 3D porous structure is selected as the fl oatable substrate. [ 9 ] Given that high carrier recombination rate is still a bottleneck of the photocatalytic technology, [ 10 ] the addition of a cocatalyst is regarded as a valid approach since the cocatalyst can act as a sink to trap the photoelectrons as well as active site for the reduction reaction. [ 11 ] Unfortunately, the state-of-theart cocatalysts are still noble metals (e.g., Pt, Au, Ru, or Pd) or their oxides that are rare and expensive. [ 12 ] Beyond them, cheap and effi cient cocatalysts have drawn more attention. Transition metal dichalcogenides (TMDs) have been more and more popular because of their fascinating physical and chemical properties. [ 13 ] The cocatalytic effect of molybdenum disulfi de (MoS 2 ) has been fully demonstrated already. [ 14 ] It was reported that tungsten-based TMDs possess better optical properties than molybdenum-based ones. [ 15 ] Moreover, an improved electrical conductivity and more active sites can be offered by selenium-based TMDs in electrocatalysis. [ 16 ] So tungsten diselenide (WSe 2 ) is expected to be a good cocatalyst. [ 17 ] Here, we demonstrate an effi cient solar photocatalytic water splitting using a fl oating sheet with a novel WSe 2 cocatalyst and nanodiamond-embedded Cu 2 O (NEC) photocatalyst. [ 18 ] This new-type artifi cial photocatalytic system makes full use of the incident light and avoids intricate operations in the recycling procedure. Meanwhile, the WSe 2 cocatalyst acts as an electron sink to promote electron-hole separation. Interestingly, this fl oating NEC/WSe 2 /CF structure achieves efficient water splitting upon simulated solar irradiation with an increased H 2 evolution rate, which is 13.2 times that of the powder-dispersing photocatalytic system. Overall, these fi ndings provide new ideas for the design of novel artifi cial photocatalytic systems.Solar photocatalytic water splitting has been a promising way to provide clean hydrogen energy. There are two weaknesses in the typical photo catalytic process in which photocatalysts are generally dispersing in water under stir. One is the inadequate utilization of light energy and the other one is the cumbersome operation in the recycling procedure. This study demonstrates an effi cient solar photocatalytic water splitting using a fl oating sheet with a novel WSe 2 cocatalyst. The sheet is fabricated by laser-depositing WSe 2 fi lm on a carbo...

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In this paper, we report a theoretical investigation of the electronic structures, electron/phonon transport properties, and electrochemical parameters of the C2N/graphene bilayer. The p-type C2N/graphene bilayer, with a direct band gap of 0.2 eV at Γ-point, exhibits promising electric conductivity similar to that of the graphene monolayer. In addition, it also shows excellent lattice thermal conductivity of 1791.1 W/m·K, compared to 82.22 W/m·K of the C2N monolayer. The theoretical capacity of C2N/graphene in Li-ion batteries is found to be 490.0 mA h/g. For Li diffusion, the energy barriers for the energetically favorable diffusion pathways are found to be in the range of 0.2–0.5 eV for both C2N monolayer and C2N/graphene bilayer. The planar diffusion coefficients of the Li atom on C2N and C2N/graphene materials are predicted to be 2.97 × 10–11 and 4.74 × 10–11 m2/s at 300 K, respectively, comparable with that of the graphene monolayer. With the help of first-principles molecular dynamics (FPMD) simulations at low temperature, it has been revealed that the Li atoms either absorbed or intercalated in the C2N/graphene heterostructure, which could migrate easily in the vertical direction through the large hole of the C2N atomic layer, and these ascended Li atoms together with absorbed Li atoms on the upper surface of the C2N monolayer are able to hop further away from the substrate, giving the strongly absorbed inner Li layer and weakly attached outer Li layer on the top of the C2N atomic layer. The outer Li atoms are mainly responsible for the ionic diffusion at room temperature. The hopping process between the nearest adsorption sites, which is obtained from routine nudge elastic band calculations, is only seen in FPMD simulations at high temperatures (>800 K).

CuNi nanoalloys with cocatalytic activities comparable to Pt for TiO2 photocatalytic H2 evolution were investigated based on the hydrogen evolution pathway.

The geometric structure and electronic structure of an imogolite nanotube have been studied using density functional theory (DFT). The calculation results indicate that the deformation of the material leads to structural electric charges on the tube wall. This hydrous aluminosilicate single-walled nanotube is a wide gap semiconductor with a direct band gap, E(g)∼3.67 eV at the Γ point, which may be promising for application in optoelectronic devices. In conjunction with the DFT calculations, molecular dynamics simulations based on empirical potentials are also performed to evaluate the mechanical properties of this material.

Recently, a novel boron monolayer with the "hexagon holes" density of η = 1/8 was repeatedly predicted to be the most stable boron sheet in different literatures. Its fascinating porous characteristic structure and sufficient surface space seem attractive and motivate researchers to perform further investigation about it. Herein, we demonstrated that the Li-decorated 1/8-boron monolayer is a kind of ultrahigh capacity hydrogen storage medium. We also established that Li atoms can be attached above the centers of the hexagonal holes in the novel 1/8-boron monolayer due to the charge transfer from Li atoms to boron atoms, and the electric field induced by the positive charged Li atoms attracts and polarizes the H 2 molecules and makes the binding strong enough for potential applications to store H 2 molecules but not dissociate them. Detailed calculations showed that the two-sided Li-decorated 1/8boron monolayer has an ultrahigh hydrogen storage capacity averagely to bind up to four H 2 molecules for each Li atom with an ideal binding energy of 0.23 eV/H 2 , which is just in the ideal binding energy scope (0.2−0.4 eV/H 2 ) for reversible hydrogen storage and corresponding to a hydrogen uptake of 15.26 wt %. These findings suggested a possible method of engineering a new structure for ultrahigh-capacity hydrogen storage materials with the reversible adsorption and desorption of hydrogen molecules, and they were expected to motivate an active line of experimental efforts.