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Electrochemical nitrogen reduction reaction (NRR) is a sustainable alternative to the Haber‒Bosch process for ammonia (NH3) production. However, the significant uphill energy in the multistep NRR pathway is a bottleneck for favorable serial reactions. To overcome this challenge, we designed a vanadium oxide/nitride (V2O3/VN) hybrid electrocatalyst in which V2O3 and VN coexist coherently at the heterogeneous interface. Since single‐phase V2O3 and VN exhibit different surface catalytic kinetics for NRR, the V2O3/VN hybrid electrocatalyst can provide alternating reaction pathways, selecting a lower energy pathway for each material in the serial NRR pathway. As a result, the ammonia yield of the V2O3/VN hybrid electrocatalyst was 219.6 µg h−1 cm−2, and the Faradaic efficiency was 18.9%, which is much higher than that of single‐phase VN, V2O3, and VNxOy solid solution catalysts without heterointerfaces. Density functional theory calculations confirmed that the composition of these hybrid electrocatalysts allows NRR to proceed from a multistep reduction reaction to a low‐energy reaction pathway through the migration and adsorption of intermediate species. Therefore, the design of metal oxide/nitride hybrids with coherent heterointerfaces provides a novel strategy for synthesizing highly efficient electrochemical catalysts that induce steps favorable for the efficient low‐energy progression of NRR. [ABSTRACT FROM AUTHOR]

Ceria nanoparticle-based free-radical scavengers for the mitigation of oxidative damage in perfluorosulfonic acid (PFSA)-based polymer electrolyte membrane fuel cells (PEMFCs) suffer from the drawbacks of lowered protonic conductivity and leaching in the acidic environment of a PEMFC. As an alternative to ceria, here we demonstrate that oxidative damage can be mitigated by functionalization of Nafion with 2-Mercaptoethanesulfonic acid (MESA) in different (0.1–1.0 wt%) ratio. The spectroscopic investigation indicated successful functionalization of MESA over the Nafion chain and resulting Nafion-MESA composite membranes displayed improved hydration and swelling behavior, and thermal and mechanical properties. At ≤60 °C (95% relative humidity), the protonic conductivity of composite membranes was higher than/equivalent to that of pristine Nafion membrane; however, at ≥70 °C it was ∼6%–8% lower. At 80 °C, conductivity of Nafion-MESA-0.1 wt%, Nafion-MESA-0.25 wt%, pristine Nafion, and state-of-the-art Nafion-CeO2−1wt% membranes were 1.72 × 10−1, 1.67 × 10−1, 1.8 × 10−1, and 1.6 × 10−1 S∙cm−1, respectively. The fluoride emission rate value for the same membranes were 0.30, 0.17, 1.39, and 0.27 mg∙g−1, respectively, thus indicating that Nafion-MESA membranes can substitute the ceria-based membranes as a chemically stable membrane electrolyte in PEMFCs. [ABSTRACT FROM AUTHOR]

We performed a systematic investigation of the Ti-xAu (x = 5, 10, 15, 20, and 40 wt%) alloys to assess the effect of addition of element Au on the microstructure, mechanical properties, and corrosion behavior of commercially pure titanium (cp-Ti). The phase and microstructure were characterized using X-ray diffraction (XRD), optical microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results indicated that the Ti-xAu alloys containing up to 15 wt% Au showed a hexagonal close-packed α-Ti structure, whereas the Ti-xAu alloys containing more than 20 wt% Au were mainly composed of the α-Ti phase and [Ti.sub.3]Au intermetallic phase. We also investigated the effect of alloying element Au on the mechanical properties (including Vickers hardness and modulus) and corrosion behavior of Ti-xAu binary alloys. The addition of gold to Ti improved its hardness. Electrochemical results showed that the Ti-xAu alloys exhibited improved corrosion resistance than cp-Ti. Keywords Ti-Au alloys * Dental material * Mechanical properties * Microstructure * Corrosion behavior, Introduction Favorable mechanical properties including high-specific strength, excellent corrosion resistance both in air and in biological fluids, and high biocompatibility have made titanium (Ti) and titanium alloys suitable for application [...]

Summary: The electrochemical nitrogen reduction reaction (ENRR) is considered an environmentally‐friendly process for ammonia production under ambient conditions, compared to the conventional Haber‐Bosch method. However, the electrochemical synthesis of ammonia suffers from poor selectivity and low efficiency owing to constrained catalytic activity and the competitive hydrogen evolution reaction (HER). Spinel‐type solid materials have received considerable interest owing to their various applications in catalysis, energy storage, and optical devices. Particularly, mixed transition‐metal oxides with a formula of A2BO4 exhibit improved catalytic activity owing to the presence of multiple balance sites for cations (A2+/3+ and B2+/3+/4+) in their structure. In this study, Ni2GeO4 nanoparticles synthesized via a facile hydrothermal method were investigated as a novel electrocatalyst for the ENRR. X‐ray photoelectron spectroscopy confirmed the presence of octahedrally‐coordinated Ni2+ and tetrahedrally‐coordinated Ge4+ in the prepared spinel‐type Ni2GeO4 material. Notably, the Ni2GeO4 electrocatalyst achieved an excellent Faradaic efficiency of 3.57% and an ammonia yield rate of 3.06 μg h−1 cm−2 at −0.1 V vs RHE, owing to the enhanced charge transfer and chemical activity caused by charge polarization between the polyhedral units. The results of this primary investigation can inspire the development of Ni2GeO4‐based electrocatalysts using innovative approaches to realize superior ENRR activity. [ABSTRACT FROM AUTHOR]