Cu–Fe Incorporated Graphene-Oxide Nanocomposite as Highly Efficient Catalyst in the Degradation of Dichlorodiphenyltrichloroethane (DDT) from Aqueous Solution

Topics in Catalysis - Fe/graphene oxide and Cu–Fe/graphene oxide nanocomposite were synthesized by the atomic implantation method to study the photocatalytic degradation of...     

Gold-vapor-assisted chemical vapor deposition of aligned monolayer WSe2 with large domain size and fast growth rate

Orientation-controlled growth of two-dimensional (2D) transition metal dichalcogenides (TMDCs) may enable many new electronic and optical applications. However, previous studies reporting aligned growth of WSe₂ usually yielded very small domain sizes. Herein, we introduced gold vapor into the chemical vapor deposition (CVD) process as a catalyst to assist the growth of WSe₂ and successfully achieved highly aligned monolayer WSe₂ triangular flakes grown on c-plane sapphire with large domain sizes (130 µm) and fast growth rate (4.3 µm·s⁻¹). When the aligned WSe₂ domains merged together, a continuous monolayer WSe₂ was formed with good uniformity. After transferring to Si/SiO₂ substrates, field effect transistors were fabricated on the continuous monolayer WSe₂, and an average mobility of 12 cm²·V⁻¹·s⁻¹ was achieved, demonstrating the good quality of the material. This report paves the way to study the effect of catalytic metal vapor in the CVD process of TMDCs and contributes a novel approach to realize the growth of aligned TMDC flakes.

     

Effect of Diamond-Like Carbon Coatings on Ball Bearing Performance in Normal,Oil-Starved,and Debris-Damaged Conditions

In this study, a process was developed to deposit wear-resistant metal-doped diamond-like amorphous hydrocarbon and carbon coatings onto spherical rolling elements. Nanocomposite WC/a-C:H, TiC/a-C, and Ti/a-C:H coatings were applied in a closed-field unbalanced magnetron sputtering system and their mechanical, compositional, and microstructural properties were examined. The ability of the coated spherical rolling elements to affect bearing performance in normal, oil-starved, and debris-damaged conditions was evaluated in thrust bearing tests. WC/a-C:H-coated spherical rolling elements (balls) exhibit the ability to improve bearing performance in normal, oil-starved, and debris-damaged conditions.     

Tuning the oxygen reduction reactivity of interconnected porous carbon by incorporation of phosphorus and activity enhancement through blending with 2D metal dichalcogenides materials

Design and construction of strong oxygen reduction reaction (ORR) electrocatalysts with high activity and durability are the main concerns in proton exchange membrane fuel cells (PEMFCs). In this study, a unique interconnected porous carbon (ICPC) and phosphorus doped ICPC (P-ICPC) were synthesized and utilized as a support matrix for ORR in alkaline medium. The activity of P-ICPC further enhanced by compositing with 2D metal dichalcogenide MoS₂ materials through facile hydrothermal method. The structural characterization indicated that the addition of phosphorus created more defective site in the carbon structure. The MoS₂/P-ICPC catalyst exhibited enhanced ORR activity, and its performance is close to commercial Pt/C catalyst with regards to current density and onset potential. The synthesized MoS₂/P-ICPC catalyst shows better stability regarding activity even after the 2000 cycles of acceleration test. The electron transfer number (n) obtained for MoS₂/P-ICPC is ～3.8, indicating that the oxygen reduction reaction proceeds via 4e^? pathway with the similar kinetics of commercial Pt/C. The current results revealed that the synthesized MoS₂/P-ICPC material might be a better catalyst for oxygen reduction reaction.     

Microwave applications to oil sands and petroleum: A review

This review provides a general overview of microwave applications in oil sands bitumen or shale oil production in petroleum upgrading. The vast oil reserves in the oil sands of Alberta will become a major source of petroleum products in the near future and a number of alternative technologies have been explored for the production and upgrading of oil sands and heavy oil. This study is based primarily on the unique selective heating capacity associated with exposure of materials to microwaves. Of particular interest are applications of microwaves for bitumen extraction, upgrading heavy oils, removing heteroatoms, and the underground heating of oil sands to reduce bitumen viscosity and allow it to be pumped to the surface. The fundamentally different method of transferring energy from the source to the sample is the main advantage of utilizing microwave energy. By directly delivering energy to microwave-absorbing materials, conventional issues such as long heating periods and energy loses can be minimized. Microwave energy was shown to be effective in some applications; however, it is not used commercially at the present time.     

Noble metal-free FeN-CNFs as an efficient electrocatalyst for oxygen reduction reaction

Carbonaceous materials containing non-precious metal atoms and doped with nitrogen have enthralled stunning attention in the field of electrochemical energy conversion systems. Herein, we demonstrated a facile method to fabricate iron and nitrogen doped carbon nanofiber (FeN-CNFs) catalyst material from ferric chloride and interfacial synthesized polyaniline (PANI) nanofibers, by carbonization process in an inert atmosphere at 800 °C. Further, synthesized material was characterized by elemental analysis and X-ray photoelectron spectroscopy (XPS) that confirms the presence of FeN bonds. The structural and morphological features are studied using various microscopy and spectroscopy techniques. The oxygen reduction reaction (ORR) activity of synthesized catalyst materials was examined by rotating disk electrode experiments in 0.1 M KOH. Among all these synthesized materials FeN-CNFs material showed enhanced ORR activity regarding current density and onset potential. Also, FeN-CNFs catalyst exhibited tolerance to methanol and durability in comparison to commercial Pt/C catalyst. The superior performance of FeN-CNFs may be attributed due to the introduction of Fe and formation of FeN bond in catalyst material.