The role and properties of interfaces are well understood in the field of semiconductors and aqueous electrochemistry, but less so in many cases of solid-state electrolytes. In this study, the interface between a solid-state proton conductor BaZr_0.9Y_0.1O_3−δ (BZY10) and a metal phase (Pt), consisting of a positively charged core and an adjacent space charge layer (SCL) with opposite charges, was investigated for proton ceramic fuel cell (PCFC) applications. Considering the H₂ oxidation reaction (HOR) at the Pt/BZY10 interface, the resistances of proton transport through the SCL (R_SCL(H⁺)) and electron charge transfer (ECT) reactions (R_ECT) were identified using the distribution of relaxation time (DRT) analysis on the impedance spectra. The R_SCL(H⁺) is shown to be independent on pH₂ and sensitive to pH₂O. And also, the positive dependency of 1/R_ECT with pH₂O reveals a decrease of the electrical potential at the Pt/BZY10 interface (Δφ(x₁)) with increasing pH₂O. With the presence of a SCL, the exchange current density (j₀) is a function of the anodic potential. As a result, the Tafel equation is modified based on the variable j₀, giving an additional resistance (R^SCL _ECT) with the expression of on top of the ideal R_ECT (absence of a SCL). At high positive bias (>0.2 V), a pronounced SCL effect on the kinetics of ECT reactions is estimated, with the ratio of R^SCL _ECT/R_ECT being over 50%. This study is a first-time experimental investigation of the SCL effect at a metal/solid-state ionic conductor interface, demonstrated in the case of the HOR.

Lithium-ion batteries (LIBs) have been widely used in the fields of smart phones, electric vehicles, and smart grids. With its opened Aurivillius structure, tungstate antimony oxide (Sb₂WO₆, SWO), constituted of {Sb₂O₂}²ⁿ⁺ and {WO₄}²ⁿ⁻, is rarely investigated as an anode for lithium-ion batteries. In this work, Sb₂WO₆ with nanosheets morphology was successfully synthesized using a simple microwave hydrothermal method and systematically studied as an anode for lithium-ion batteries. The optimal SWO (SWO-60) exhibits a high specific discharge capacity and good rate capability. The good electrochemical performance could be ascribed to mesoporous nanosheets morphology, which is favorable for the penetration of the electrolyte and charge transportation. The results show that this nanostructured SWO is a promising anode material for LIBs.

A novel, efficient and durable ZrP@PDA/Ag nanocatalyst was prepared via the facile reduction and deposition of silver nanoparticles (AgNPs) on two dimensional (2D) α-zirconium phosphate (ZrP) nanosheets using bio-inspired dopamine chemistry. The formation, adhesion and dispersion of AgNPs were confirmed by the full morphological and structural characterizations including SEM, TEM, FTIR, TGA, WXRD, and XPS. This ZrP@PDA/Ag nanocatalyst was evaluated by the reduction of 4-nitrophenol into 4-aminophenol, utilizing UV-vis absorption spectroscopy to monitor the reaction solution with a trace silver content of 0.125 μg mL⁻¹. ZrP@PDA/Ag exhibits a superior catalytic activity compared with other noble metal nanocatalysts due to its high turnover frequency of 32.36 min⁻¹ at room temperature without stirring, which is as high as almost 10 times that of the reported nanocatalysts using 2D graphene and silica supports. Furthermore, due to the excellent catalytic recyclability of ZrP@PDA/Ag it has very promising prospects in the treatment of organic pollutants in water.

Hydrogen oxidation reaction (HOR) mechanisms on a novel perovskite anode with a nominal composition of La_0.3Sr_0.7Fe_0.7Cr_0.3O_3-δ (LSFCr-3) were systematically investigated for solid oxide fuel cell (SOFC) applications. In terms of electrochemical impedance spectroscopy study of LSFCr-3-based half cells in various applied DC bias, hydrogen (pH₂) and water vapor partial pressure (pH₂O), the HOR on the LSFCr-3 perovskite was suggested to be rate-limited by the dissociative adsorption of hydrogen. At constant pH₂O and pH₂, the concentration of oxygen vacancies on the LSFCr-3 surface is much higher than that in the bulk. Importantly, a positive impact of water vapor on the process of dissociative adsorption of hydrogen was demonstrated for the perovskite anodes. This finding is explained by the hydration of surface oxygen vacancies, that formed more active oxygen anions sites. Under humid reducing atmosphere, the exact composition of the bulk of the LSFCr-3 is estimated to be La_0.34Sr_0.67Fe^{3 +}_0.7Cr^{3 +}_0.29O_2.65 at 800°C. On the surface of the LSFCr-3 anode, the average oxidation state of B-site cations (Fe and Cr) is found to be lower than that in the bulk, resulting in a presence of Cr³⁺, Fe²⁺ and Fe³⁺. Cr³⁺ on the surface contributes to holding more active oxygen anions for the dissociative adsorption of hydrogen, due to its backbone action in the perovskite lattice structure. This effect of Cr³⁺ is suggested to be of great benefit to the electrochemical performance of the LSFCr-3 perovskite anode.