Pt Electrocatalyst Prepared by Hydrothermal Reduction onto the Gas Diffusion Layer for High-Temperature Formic Acid and Ethanol Fuel PEMFC

An alternative method for the preparation of PEMFC electrodes is presented in this work based on the direct deposition of Pt particles onto the gas diffusion layer (Pt@GDL) by hydrothermal reduction of the H2PtCl6 precursor from formic acid, ethylene glycol, and ethanol reductive solutions. There is a successful anchorage of Pt particles via the formation of Pt crystal aggregates. The influence of the reducing agent concentration and temperature was studied to analyze their influence on the size, morphology, and distribution of the Pt particles on the gas GDL. The prepared Pt@GDL was tested for formic acid and ethanol high-temperature H3PO4-doped PEMFC. The Pt@GDL prepared in the formic acid reductive atmosphere presented the best performance associated with the formation of smaller Pt crystals and a more homogeneous dispersion of the Pt particles. For formic acid and ethanol-fed high-temperature PEMFC using a H3PO4-doped polybenzimidazole membrane as the solid electrolyte, maximum power densities of 0.025 and 0.007 W cm−2 were drawn at 200 °C, respectively.

Mechanically Tunable Spongy Graphene/Cellulose Nanocrystals Hybrid Aerogel by Atmospheric Drying and Its Adsorption Applications

For expanding applications of spongy graphene aerogels (GAs) cost-effectively, we report a marriage of the two-step hydrothermal reduction and atmospheric drying method to fabricate a spongy CNC-graphene aerogel (CNG) with oil/water selectivity and tunable mechanical strength by a low-cost and straightforward approach. The reduced graphene oxide (rGO) with CNC by the ice-templated method can give rise to forming the hierarchical structure of hybrid GAs within the PUS network. Meanwhile, the fractured structure of PUS with a pre-compressive step arouses more versatility and durability, involving its selective and high-volume absorbability (up to 143%). The enhanced elastic modulus and more significant swelling effect than pure sponge materials give it a high potential for durable wastewater treatment.

SYNTHESIS, CHARACTERISTIC AND ACTIVITY OF NANOSIZED Cu–Me (Me–Co, Zn, Ni) OXIDE SYSTEMS IN CO OXIDATION IN THE PRESENCE OF H2

Nanooxides of Cu–Me composition (Me–Co, Zn, Ni) were synthesized by hydrothermal reduction of metal salts with subsequent calcination and the influence of their properties (size, morphology, structure) on catalytic activity of deep CO oxidation reaction in the presence of H2 was considered. The nanooxides have been characterized by XRD and SEM methods. It was revealed that particles of Cu–Co–O are nanoplates (30–35 nm), and Cu–Zn–O (12.5–20 nm) are nanorods. The SEM method revealed a higher structural organization of the Cu–Сo–O particles than Cu–Zn–O; the growth of nanocrystals is shown by varying the magnification of the scale grid of images. The highest activity of the Cu–Co–O system was found among the mentioned and corresponding individual oxides. The effect of metal (Cu/Co) ratio on the dispersibility and morphology of nanoparticles and their activity has been studied. The non-additive increase in activity is explained by the redox properties of cobalt oxides and the contribution of copper to electronic state of this element. The variation of composition, as well as high dispersibility (30–35 nm) make it possible to reduce the temperature of oxidation beginning (T50%) of CO to less than 1150C

Effect of Functionalization of Reduced Graphene Oxide Coatings with Nitrogen and Sulfur Groups on Their Anti-Corrosion Properties

Electrophoretic production of anticorrosion carbonaceous coatings on copper could be successfully performed by anodic oxidation of negatively charged graphene platelets suspended in an aqueous solution. The various platelets were synthesized by Hummer’s method followed by a hydrothermal reduction in the presence of NH4SCN which was expected to substitute some parts of graphene structure with nitrogen and sulfur groups. X-ray photoelectron spectroscopy analysis confirmed that the graphene precursors, as well as the coatings, contained typical nitrogen groups, such as pyridinic and pyrrolic, and sulfur groups, such as thiol, thiophene, or C-SO2. However, due to oxidation during deposition, the qualitative and quantitative composition of the graphene coatings changed relative to the composition of the precursors. In particular, the concentration of nitrogen and sulfur dropped and some thiophene groups were oxidized to C-SO2. Studies showed the functionalized coatings had a uniform, defect-free, hydrophobic, more adhesive surface than nonmodified films. The corrosion measurements demonstrated that these coatings had better protective properties than the ones without these heteroatoms. This behavior can be assigned to the catalytic activity of nitrogen towards oxidation of C-SO2 groups to C-SO3H with oxygen.

Controlled synthesis of γ-MnOOH nanorods via a facile hydrothermal method for the high-performance Li-ion batteries

In this work, a hydrothermal reduction route was applied for the controlled production of MnOOH nanohydrangeas and MnOOH nanorods. The structure and morphology of formed products were characterized. Both MnOOH...

Band Gap Tuning of Photo Fenton-like Fe3O4/C Catalyst through Oxygen Vacancies for Advanced Visible Light Photocatalysis

In this contribution, low-cost Fe3O4/C nanocomposites has been targeted by a simplistic single-pot D-glucose mediated hydrothermal reduction method using a single iron precursor (FeCl3. 6H2O) acquired from accumulated iron ore...