We report a reinterpretation of the reduction of 4-nitrophenol catalyzed by silver nanoparticles. Mass spectrometry and ultraviolet−visible light spectroscopy measurements support the existence of 4-nitrosophenol as a stable reaction intermediate. We propose that dissolved oxygen is consumed, both by oxidizing 4nitrosophenol (an intermediate) and reoxidizing the reduced catalyst surface, resulting in the commonly observed "induction period" in the reaction kinetics. Upon complete consumption of dissolved oxygen, subsequent reduction to 4-aminophenol can occur. A complete kinetic analysis including modeling is presented, conceptually fitting data from recent reports in the literature, as well as fitting data from our own experiments.

Transition metal dichalcogenides (TMDs) of molybdenum and tungsten are layered van der Waals materials that exhibit a rich array of polytypes. The different possible arrangements of the constituents of the “two-dimensional” MX2 sheets (where M = group 4–10 elements, X = chalcogen) give rise to a host of interesting and tunable phenomena. Molybdenite, or molybdenum disulfide (MoS2) in its most abundant and thermodynamically stable form, 2H-MoS2, is perhaps the most widely used TMD, though the potential applications of its metastable polytypes have been recognized only recently. From among the polytypes, the 3R-MoS2 (rhombohedral) phase has attracted the most interest because of its thermodynamic stability, ABC stacking (as opposed to the AA′ of the more common 2H-MoS2), and lack of inversion symmetry. These properties make it an excellent candidate for photonics, optoelectronics, and catalysis. Because the literature on this material is rapidly expanding, this review seeks to summarize the history, known and predicted characteristics, syntheses, and applications, as well as common misconceptions of, and surrounding, 3R-MoS2. Although the review is chemically focused, it includes suggested reading to cover a broader scope.

The unique anisotropy, polytypism, and abundance of molybdenum disulfide make it a singularly versatile material for a range of catalytic, electrochemical, and tribological applications. By employing a hydrothermal synthesis, a...

Reactive methanol removal either by adsorption or by azeotropic distillation promotes complete conversion of different alcohols to the corresponding carbonates.

Chevrel phases (M x Mo6S8) are a class of molybdenum chalcogenide materials that are attractive candidates for active non-noble metal catalysts due to the relatively low coordination of their molybdenum moieties. Conventionally, the lengthy and energy-intensive synthesis of Chevrel phases (CPs) produces highly crystalline, low surface area materials. In this work, a synthetic approach leading to a Chevrel phase with an unprecedented nanostructure is presented. The resultant material is fully characterized using a variety of spectroscopic, microscopic, and electrochemical techniques. In electrochemical testing aimed at catalyzing the hydrogen evolution reaction (HER), this nanostructured catalyst shows a substantially lower overpotential than an equivalent MoS2 phase with a similar nanostructure. Furthermore, the nanostructured Chevrel phases prove to be easily modified by electrochemical intercalation, which allows performance fine-tuning, revealing a family of versatile and tuneable catalysts.

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We report a research-enhanced undergraduate laboratory practical in which students synthesize and characterize color-controllable, stable silver nanoparticles for use in a simple catalytic reaction analyzed by UV–vis spectroscopy. The practical has been prepared for students using electronic laboratory notebooks, enables collaborative data sharing, and can be altered to suit time, experience, and instrumentation constraints. This experiment is conducted as part of our Talented Student Program and introduces students to the themes of nanoscience, catalysis, and green chemistry as well as to a range of relevant instrumentation and techniques.

The full extent to which the electrochemical properties of MoS 2 electrodes are influenced by their morphological characteristics, such as crystalline disorder, remains unclear. Here, we report that disorder introduced by ball-milling decreases the Faradaic component of cell capacity and leads to increasingly pseudo-capacitive behaviour. After high temperature annealing, a more battery-like character of the cell is restored, consistent with a decrease in disorder. These findings aid the optimisation of MoS 2 electrodes, which show promise in several battery technologies.