Stability of MoS2 Nanocatalysts for the Slurry-Phase Catalytic Hydrogenation of Anthracene.

The stability of both the structure and activity of MoS2 nanocatalysts is crucial for minimizing the catalyst cost of the slurry-phase (SP) catalytic hydrogenation. MoS2-GP and MoS2-SP catalysts were, respectively, obtained by gas-phase (denoted as GP) and SP aging of fresh MoS2 catalysts. The MoS2-SP catalyst demonstrated a comparable catalytic hydrogenation activity to that of the fresh MoS2 catalyst, which is about 1.7 times of that for the MoS2-GP catalyst. After 12 cycles of the MoS2-SP catalyst, the obtained Cy12 catalyst demonstrates a retention of 92.0% of its initial catalytic activity. The MoS2-SP catalyst exhibits an impressive stability of catalytic hydrogenation. The MoS2-SP catalyst exhibits average stacking layers of 3.3 and an average slab of 5.2 nm and exposes 14.0% of active sites. The MoS2-SP catalyst can serve as a highly active and stable catalyst for catalytic hydrogenation. This finding can offer valuable insights into the stability of the hydrogenation catalyst in SP hydrogenation technology.

Constructing layer-by-layer self-assembly MoS2/C nanomaterials by a one-step hydrothermal method for catalytic hydrogenation of phenanthrene.

Layer-by-layer self-assembly MoS2/C nanomaterials are constructed through the electrostatic adsorption between MoS2 nuclei with positive charge and C nuclei with negative charge using a facile one-step hydrothermal method. The layer-by-layer self-assembly MoS2/C catalysts with high exposure of catalytic hydrogenation active sites exhibit enhanced catalytic performance in phenanthrene hydrogenation.

Tailored Cl- Ligation on Supported Pt Catalysts for Selective Primary C-H Bond Oxidation.

It is challenging to achieve high selectivity over Pt-metal-oxide catalysts widely used in many selective oxidation reactions because Pt is prone to over-oxidize substrates. Herein, our sound strategy for enhancing the selectivity is to saturate the under-coordinated single Pt atoms with Cl- ligands. In this system, the weak electronic metal-support interactions between Pt atoms and reduced TiO2 cause electron extraction from Pt to Cl- ligands, resulting in strong Pt-Cl bonds. Therefore, the two-coordinate single Pt atoms adopt a four-coordinate configuration and thus inactivated, thereby inhibiting the over-oxidation of toluene over Pt sites. The selectivity for the primary C-H bond oxidation products of toluene was increased from 50.1 to 100%. Meanwhile, the abundant active Ti3+ sites were stabilized in reduced TiO2 by Pt atoms, leading to a rising yield of the primary C-H oxidation products of 249.8 mmol gcat-1. The reported strategy holds great promise for selective oxidation with enhanced selectivity.

Remarkable MnO2 structure-dependent H2O promoting effect in HCHO oxidation at room temperature.

H2O is often critical in determining the activity and stability of metal oxide catalysts for HCHO oxidation; however, synthesis of metal oxide catalysts with super resistance to H2O remains a challenging. Herein, we synthesized Akhtenskite-type MnO2 catalyst with Mn-O-Mn stretching along MnO6 octahedra layers, which promotes the utilization of the associatively adsorbed H2O. The activity and stability of formaldehyde oxidation at room temperature enhanced in humid air. Diffuse-reflectance infrared Fourier transform (DRIRFT) spectroscopy was used to characterize the H2O adsorption and intermediate species. The associatively adsorbed H2O promotes the oxidation of formaldehyde to CO2 via the formic acid intermediate. The service life of MnO2 is prolonged due to formic acid generation. MnO2 gradually deactivates when formic acid accumulates and forms formate and hydrogen carbonate species. This study provides significant insights into the development of a high-efficiency MnO2 catalyst for formaldehyde oxidation in humid air, and the developed MnO2 catalyst is a promising candidate for application in practical formaldehyde elimination.

Patterning of polyoxometalate rings on gold nanorods.

We report a facile method for the self-assembly of various polyoxometalates (POMs) on cetyltriethylammonium bromide-covered gold nanorods (GNRs) into an ordered array of POM rings along their long axis. The periodic distance of POM rings can be tuned by the POM charge and the transverse curvature of GNRs.

Polymer Grafted Aluminum Nanoparticles for Percolative Composite Films with Enhanced Compatibility.

Aluminum nanoparticles hold promise for highly energetic materials and sustainable surface plasmonic materials. Most of the commercial Al nanoparticles are prepared via a high-throughput electrical explosion of wires method (up to 200 g h-1). However, the use of Al nanoparticles produced by an electrical explosion of wires is limited by their micrometer-sized aggregations and poor stability. Here, we use polystyrene with ⁻COOH end-group to graft onto isolated Al nanoparticles and dramatically enhance their colloidal stability in various organic solvents. We further demonstrate that the polystyrene grafted Al nanoparticles can be doped into polystyrene films with high compatibility, leading to enhanced dielectric properties, such as higher dielectric constant, lower dielectric loss, and stronger breakdown strength. Moreover, the composite film can improve the moisture resistance of embedded Al nanoparticles.