Electrochemical CO2 reduction is a key technology to recycle CO2 as a renewable resource, but adsorbing CO2 on the catalyst surface is challenging. We explored the effects of reduced graphene oxide (rGO) in Sn/rGO composites and found that the CO2 adsorption ability of Sn/rGO was almost 4-times higher than that of bare Sn catalysts. Density functional theory calculations revealed that the oxidized functional groups of rGO offered adsorption sites for CO2 toward the adjacent Sn surface and that CO2-rich conditions near the surface facilitated the production of formate via COOH* formation while suppressing CO* formation. Scanning electrochemical cell microscopy directly indicated that CO2 reduction was accelerated at the interface, together with the kinetic suppression of undesirable and competitive hydrogen evolution at the interface. Thus, the synergism of Sn/rGO ensures a substantial/rapid supply of CO2 from the functional groups to the Sn surface, thereby enhancing the Faradaic efficiency 1.8-times compared with that obtained with bare Sn catalysts.

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The discharged state affects the charge transfer resistance of lithium-ion secondary batteries (LIBs), which is referred to as the depth of discharge (DOD). To understand the intrinsic charge/discharge property of LIBs, the DOD-dependent charge transfer resistance at the solid–liquid interface is required. However, in a general composite electrode, the conductive additive and organic polymeric binder are unevenly distributed, resulting in a complicated electron conduction/ion conduction path. As a result, estimating the DOD-dependent rate-determining factor of LIBs is difficult. In contrast, in micro/nanoscale electrochemical measurements, the primary or secondary particle is evaluated without using a conductive additive and providing an ideal mass transport condition. To control the DOD state of a single LiFePO4 active material and evaluate the DOD-dependent charge transfer kinetic parameters, we use scanning electrochemical cell microscopy (SECCM), which uses a micropipette to form an electrochemical cell on a sample surface. The difference in charge transfer resistance at the solid–liquid interface depending on the DOD state and electrolyte solution could be confirmed using SECCM.

Electric double‐layer capacitors (EDLCs) that store electrical energy in the interface between an electrolyte and a solid electrode are favorable energy storage systems that demonstrate high‐power density, excellent cycle stability, and low environmental impact. To increase the operating voltage and improve the capacitance of EDLCs, it is essential to investigate the relationship between the degradation process and structural properties of activated carbon. In the current study, we used scanning electrochemical cell microscopy (SECCM) to assess the site‐specific degradation mechanisms caused by electrolyte decomposition. To simplify the structural properties of activated carbon, we used the highly oriented pyrolytic graphite (HOPG) as a model substrate to distinguish the edge and the basal planes of activated carbon. The mobile and nanoscale electrochemical cell provides local cyclic voltammetry (CV) to examine the difference in the degradation process at the edge and basal planes of HOPG. SECCM's nanoscale electrochemical cell can suppress the impact of capacitive current and can therefore be used to clearly measure the current associated with degradation caused by electrolyte decomposition. SECCM's local CV measurements directly exposed the degradation reaction that occurred at the edge plane in the positive potential range.

An extrusion process for finely grained, recycled hot extrusion material fabricated by hot pressing chips obtained in machining of AZ91D, has been investigated for achieving its higher strength and higher strain-rate superplasticity. Fine dispersion of b-phase Mg 17 Al 12 particles in the matrix of the pressed billet, was obtained through solution heat treatment at 723 K followed by aging at 523 K. Further, by cooling the gate of the extrusion die with nitrogen gas during the hot extrusion, the temperature rise of the extruded billet was suppressed, resulting in fine grain sizes. The combined method of the solution heat treatment and the nitrogen-gas cooling during the extrusion, made it possible to refine average grain size of the extruded material down to less than about 3.5 mm, improving its room temperature strength and superplastic property. The grain refinement was especially effective to improve 0.2% proof stress of AZ91D extrusion alloy. The AZ91D alloy extruded at a temperature of 553 K, showed a superplastic elongation of about 250% at a tensile test temperature of 548 K and a high strain rate of 1ϫ10 Ϫ2 s Ϫ1. The strain rate sensitivity index m of the observed superplasticity was about 0.56. During the superplastic deformation, grain boundary sliding was observed. Its activation energy was about 94.8 kJ/mol. This value is close to that for the grain boundary diffusion of pure magnesium.

Uni-directionally arranged mesoporous titanium oxide powders were prepared for titanium sheet through electrochemical anodization, one-step anodization with mixture of HNO3 and H2SO4 or two-steps anodization with HNO3 after H2SO4. The characterization of novel titanium oxide was carried out by XRD, XPS, SEM and TEM. The doping of S and N was confirmed with XPS evaluations during the anodization process in mixture of HNO3 and H2SO4. Furthermore, the S and N co-doped titanium oxide possessed the unique mesoporous structure.

In this study, glucose oxidase (GOx) was immobilized on the electrode surface by layer‐by‐layer and gel membrane technique and characterized the GOx immobilized film morphology, H2O2 permeability, and glucose response. Concanavalin A (Con A)‐GOx multilayer electrodes showed higher glucose‐related current response than GOx‐bovine serum albumin gel membrane‐coated electrode, a common modification method. The thin thickness of the Con A/GOx multilayer film efficiently catalyzed the enzymatic reaction, and H2O2 was produced near the electrode surface, resulting in an immediate electrode response.