Zr2N2O Coating-Improved Corrosion Resistance for the Anodic Dissolution Induced by Cathodic Transient Potential

Study on Corrosion Resistance and Conductivity of TiMoN Coatings with Different Mo Contents under Simulated PEMFC Cathode Environment

TiMoN coatings with different Mo contents on a SS316L substrate are deposited by using closed field unbalanced magnetron sputtering ion plating (CFUMSIP) technology to enhance the corrosion resistance and durability of stainless steel (SS) bipolar plates (BPs) in proton exchange membrane fuel cell (PEMFC) during the start-up/shut-down process. The electrochemical test results illustrate that TiMoN-4A coating has extremely good corrosion resistance compared to other coatings. The potentiostat polarization (+0.6 V_SCE) tests indicate that the corrosion current density (I_corr) of TiMoN-4A coating is 5.22 × 10⁻⁷A cm⁻², which meets the department of energy 2020 targets (DOE, ≤1 × 10⁻⁶ A cm⁻²). Otherwise, TiMoN-4A coating also exhibits the best corrosion resistance and stability in potentiostatic polarization, electrochemical impedance spectroscopy (EIS), and high potential (+1.2V_SCE) polarization tests. The interfacial contact resistance (ICR) measurement results show that TiMoN-4A coating has the minimum ICR of 9.19 mΩ·cm², which meets the DOE 2020 targets (≤10 mΩ·cm²).

Enhanced photoelectrochemical activity of α-Fe2O3/TiO2 nanoheterojunction by controlling hydrodynamic conditions

Interfacial heterostructuring has appeared to be an efficient strategy to address the efficiency and applicability of the photocatalysts in solar energy conversion. Herein, we developed one-dimensional (1D) α-Fe₂O₃/TiO₂ nanoheterojunction arrays for enhanced photoelectrochemical (PEC) activity. α-Fe₂O₃ nanotubes were firstly prepared via anodization under controlled hydrodynamic conditions to increase the efficiency. 1D α-Fe₂O₃/TiO₂ nanoheterojunction arrays were then prepared through a hydrothermal treatment and a subsequent annealing process. A controlled anodization by modulating the hydrodynamic conditions, added a fine coating of TiO₂ overlayer, to finally give an optimized composition and geometry for improved light absorption and spatial charge separation efficiency. Consequently, the optimized α-Fe₂O₃ generated a photocurrent of 0.07 mA cm^-2 (3.5 times higher than that of pristine α-Fe₂O₃), and the as-obtained α-Fe₂O₃/TiO₂ nanoheterojunction exhibited a photocurrent intensity of 0.12 mA cm^-2 (about 6 times higher than that of pristine α-Fe₂O₃). A long-term stability can also be ensured. The well-controlled architectures provides a guideline for synthesis of advanced nanomaterials.

Nonwetting Behavior of Al-Co Quasicrystalline Approximants Owing to Their Unique Electronic Structures

Good wetting is generally observed for liquid metals on metallic substrates, while poor wetting usually occurs for metals on insulating oxides. In this work, we report unexpected large contact angles for lead on two metallic approximants to decagonal quasicrystals, namely, Al₅Co₂ and Al₁₃Co₄. Intrinsic surface wettability is predicted from first principles, using a thermodynamic model based on the Young equation, and validated by the good agreement with experimental measurements performed under ultra-high vacuum by scanning electron microscopy. The atomistic details of the atomic and electronic structures at the Pb-substrate interface, and the comparison with Pb(111)/Al(111), underline the influence of the specific electronic structures of quasicrystalline approximants on wetting. Our work suggests a possible correlation of the contact angles with the density of states at the Fermi energy and paves the way for a better fundamental understanding of wettability on intermetallic substrates, which has potential consequences in several applications such as supported catalysts, protective coatings, or crystal growth.