MoS2(1-x) Se2x single-layer films are prepared using a mixture of organic selenium and sulfur precursors as well as a solid molybdenum source. The direct bandgaps are found to scale nearly linearly with composition in the range of 1.87 eV (pure single-layer MoS2 ) to 1.55 eV (pure single-layer MoSe2 ) permitting straightforward bandgap engineering.

Novel CdS quantum dot (QD)-coupled graphitic carbon nitride (g-C 3 N 4 ) photocatalysts were synthesized via a chemical impregnation method and characterized by Xray diffraction, transmission electron microscopy, ultraviolet− visible diffuse reflection spectroscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and photoluminescence spectroscopy. The effect of CdS content on the rate of visible light photocatalytic hydrogen evolution was investigated for different CdS loadings using platinum as a cocatalyst in methanol aqueous solutions. The synergistic effect of g-C 3 N 4 and CdS QDs leads to efficient separation of the photogenerated charge carriers and, consequently, enhances the visible light photocatalytic H 2 production activity of the materials. The optimal CdS QD content is determined to be 30 wt %, and the corresponding H 2 evolution rate was 17.27 μmol•h −1 under visible light irradiation, ∼9 times that of pure g-C 3 N 4 . A possible photocatalytic mechanism of the CdS/g-C 3 N 4 composite is proposed and corroborated by photoluminescence spectroscopy and photoelectrochemical curves.

Highly ordered magnetic Ni nanotubules (see Figure) have been successfully prepared. Electrodeposition in the pores of an alumina membrane modified with an organoamine as pore‐wall modifying agent results in a perfectly ordered array of such metal nanotubules tens of micrometers long. These metal nanotubules with open ends could be employed for the creation of materials with special magnetic, optical, or electrical properties.

Sputtering of MoS2 films of single-layer thickness by low-energy argon ions selectively reduces the sulfur content of the material without significant depletion of molybdenum. X-ray photoelectron spectroscopy shows little modification of the Mo 3d states during this process, suggesting the absence of significant reorganization or damage to the overall structure of the MoS2 film. Accompanying ab initio molecular dynamics simulations find clusters of sulfur vacancies in the top plane of single-layer MoS2 to be structurally stable. Measurements of the photoluminescence at temperatures between 175 and 300 K show quenching of almost 80% for an ~10% decrease in sulfur content.

A graphene-supported Ag 3 PO 4 /Ag/AgBr water oxidation photocatalyst was prepared by a photoassisted deposition−precipitation reaction, followed by a hydrothermal treatment. The composite photocatalyst exhibits double the O 2 -production activity than that of bare Ag 3 PO 4 under visible light irradiation. Moreover, it exhibits enhanced activity in comparison to unsupported Ag 3 PO 4 /Ag/AgBr, to graphenesupported bare Ag 3 PO 4 powder as well as to Ag/AgBr powder. This increase in activity is attributed to a combination of depletion of the conduction band of the as-synthesized ndoped Ag 3 PO 4 material and a downshift of the Ag 3 PO 4 valence band due to the pinning of its conduction band at the silver Fermi level, a process that is assisted by charge transfer and distribution onto the graphene support.

We demonstrate bandgap tuning of a single-layer MoS2 film on SiO2/Si via substitution of its sulfur atoms by selenium through a process of gentle sputtering, exposure to a selenium precursor, and annealing. We characterize the substitution process both for S/S and S/Se replacement. Photoluminescence and, in the latter case, X-ray photoelectron spectroscopy provide direct evidence of optical band gap shift and selenium incorporation, respectively. We discuss our experimental observations, including the limit of the achievable bandgap shift, in terms of the role of stress in the film as elucidated by computational studies, based on density functional theory. The resultant films are stable in vacuum, but deteriorate under optical excitation in air.

Organocatalytic atom transfer radical polymerization (O-ATRP) is recently emerging as an appealing method for the synthesis of metal-free polymer materials with well-defined microstructures and architectures. However, the development of highly effective catalysts that can be employed at a practical low loading are still a challenging task. Herein, we introduce a catalyst design logic based on heteroatom-doping of polycyclic arenes, which leads to the discovery of oxygen-doped anthanthrene (ODA) as highly effective organic photoredox catalysts for O-ATRP. In comparison with known organocatalysts, ODAs feature strong visible-light absorption together with high molar extinction coefficient (ε455nm up to 23,950 M–1 cm–1), which allow for the establishment of a controlled polymerization under sunlight at low ppm levels of catalyst loading.

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