We developed an electrochemical cell for scanning electron microscopy observation of the interfaces between an electrode and an electrolyte in the processes of electro-plating and stripping, which were controlled and simultaneously measured by cyclic voltammetry with two terminals. Lead dendrites on an Au electrode in a 1.5 M Pb(NO₃)₂ solution were grown and decomposed during a cyclic of voltammogram. Initially Pb islands formed, followed by dendritic growth. The applied voltage and sweep rate dependence of the processes will be discussed.

We have developed electrochemical tip-enhanced Raman spectroscopy (EC-TERS). In this presentation, we present the EC-TERS spectra of benzenethiol self-assembled monolayers on Au(111) before and after the oxidative desorption.

Remarkable electron-proton correlation properties have been reported for organic crystals of the Cat-TTF molecule, which consists of catechol (Cat) and tetrathiafulvalene (TTF) moieties. In our study, we successfully assembled the proton-donating Cat-TTF monolayer on the proton-accepting imidazole-terminated alkanethiolate self-assembled monolayer in a manner of self-assembly. The characteristics of the heterobilayers were elucidated by means of infrared reflection absorption spectroscopy, photoelectron spectroscopy, X-ray absorption spectroscopy, and theoretical calculations. We discuss the ability to control the electron-proton correlation properties for the Cat-TTF layer.

It has long been suggested that life probably emerged through the chemical evolution that biopolymers have been formed by the polymerization of simple monomers, such as amino acids. Furthermore, it is reported that mineral surfaces such as Titanium dioxide played as a catalyst in polymerization processes. On the other hand, it is a still crucial issue that if peptide sequences could be selectively formed or it depends on mineral species. The objective of this work is to analyze amino acids reactivity on the mineral surface and investigate systemically about the selectivity on the dimerization of amino acids.

Magnetic moment of ortho-H₂ depends on its nuclear spin as well as internal rotational states. A combined use of a magnetic hexapole and a supersonic seeded H₂ beam allowed us to produce a hyperpolarized H₂ beam. Its spin polarization measurement, spin inversion, and a time-of-flight analysis suggesting the rotational M-state selection of o-H₂ will be presented.

Reaction step of CO₂ dissociative adsorption on Cu surface is studied long time because this reaction is late limiting and first step of reverse water gas shift reaction. However, nobody has experimented what is focused on CO₂ molecule energy. Therefore, we clarified CO₂ dissociative adsorption dynamics on single crystal Cu surface by using supersonic molecular beam which can control translational and vibrational energy of CO₂ molecule. As a result, we revealed that CO₂ dissociative adsorption reaction is promoted by increasing CO₂ energy.

CO₂ dissociation on transition metal catalysts is an important process for methane dry-reforming reaction, but the rate of dissociation on single-crystal metal surface has not been measured so far. In the present study, CO₂ dissociation process is investigated by the measurement of ¹³CO₂ and ¹²CO exchange reaction in a reactor directly attached to an UHV system as a function of temperature or CO pressure.

N-doped carbon materials have been attention which shows oxygen reduction reaction (ORR) activity. We clarified Pyridinic-N (nitrogen atom bound to C atoms) forms an active site for ORR. An ORR mechanism on N-doped carbon has been not clarified by experimental method. Recently, we also demonstrated dibenz[a,c]acridine, Pyridinic-N containing molecules, periodically adsorbed on HOPG (DA/HOPG) shows comparable ORR activities with that for Pyridinic-N-doped carbon. Herein, we investigated the state near nitrogen about DA/HOPG as model catalyst after the immersion into acid condition and after applying to voltage in acid condition by X-ray photoelectron spectroscopy measurement and infrared absorption spectroscopy measurement.

In this study, in-situ Raman spectroscopy and IR spectroscopy were operated to reveal ORR elementary steps under acidic condition on molecular catalyst containing pyri-N and strongly-hydrophobic. We found the pyri-N was protonated in sulfuric acid before ORR starts. At the same time, hydrogensulfate (HSO₄⁻) adsorbed as a counter anion. DFT calculations also showed these protonation steps and the protonated pyri-N can recierve an electron to form neutral atomic with the application of voltages. These hydrogenation steps could trigger the O₂ adsorption effectively.

In catalyst layers of polymer electrolyte fuel cell (PEFC), an ionomer such as Nafion is used as a proton conducter and a binder for catalyst particles. Although the interface between a Pt catalyst (Pt) and the ionomer influences the performance of PEFC, the effect of the Pt/ionomer interfacial structure on oxygen reduction reaction (ORR) activity is still unclear. We prepare Nafion films with different thicknesses on a Pt single crystal electrode, and the correlation between the ionomer film thickness and ORR activity was examined.

Methanol synthesis reaction from CO₂ hydrogenation is carried out on Cu-based catalyst under high temperature and pressure conditions. Therefore, methanol synthesis reaction is required to develop a lower-load conversion system. The purpose of this study is to elucidate the reaction mechanism and active site in methanol synthesis reaction from CO₂ hydrogenation. The experiment was performed using in-situ FT-IR to observe the adsorbed species generated on the Cu-based powder catalyst surface. Elucidation of the reaction mechanism and the active site can provide guidelines for the design of highly active catalysts.

In the catalytic reaction that converts CO₂ into chemically useful methanol, the development of a low load operating catalyst has become an issue. In this study, hydrogen is reacted with formate, which is an initial reaction intermediate of methanol synthesis, generated on single crystal Cu (111) surface, and we aim to elucidate the elementary process of formate hydrogenation which is not clarified experimentally. In the experiments, reflection infrared absorption spectroscopy and thermal desorption spectroscopy were used to observe and identify adsorbed species on the catalyst surface.

Monatomic-layered Pt clusters strongly interacting with a Si substrate have different turnover rates of CO oxidation in heating and cooling processes even at the same temperature and partial pressures of CO and O₂; bistability. Temperature-programed desorption measurements show the adsorption energy of CO of this system is lower than that of bulk Pt surfaces. On the basis of these experimental results, it is evidenced that (1) this system possesses higher activity of dissociative adsorption of O₂ owing to electron-donating catalysis and (2) Pt₃₀ maintains the dissociative-adsorption activity at lower temperature than Pt₂₀.

We have examined adsorption, diffusion and desorption processes of methanol on a Pt/TiO₂(110) model catalyst surface by STM. Although methanol molecules were not dissociatively adsorbed on the perfect TiO₂(110) terraces at room temperature, they were dissociated at Pt nanoparticles to form methoxy species, which then spilled over to the substrate 5 fold-coordinated Ti sites (Ti_5c). They diffused along the [001] direction and also jumped to the next Ti_5c rows, but never go over the step edge. Their density gradually decreased when the surface was stored in UHV, whose rate increased as the density of Pt nanoparticles increased.

Polarization-dependent total reflection fluorescence X-ray absorption fine structure (PTRF-XAFS) is a powerful technique to determine a 3D structure of highly dispersed metal species on a single-crystal oxide surface which is considered as a model of oxide-supported metal catalysts. Recently we have developed an operando PTRF-XAFS technique applied to metal nanoparticles on oxide surfaces. The apparatus consists of a compact vacuum chamber which works both as the PTRF-XAFS cell and batch-type reactor. In our talk, we will describe the operando PTRF-XAFS technique and its application to a Pt/Al₂O₃(0001) surface during CO oxidation process.

Experiments were conducted to clarify the adsorption of hydrogen on Pd-Cu single atom alloy surface and the effect of hydrogen on adsorbed species.They were conducted at SPring-8 and PF. First, we deposited Pd on a Cu surface. Thereafter, formic acid was adsorbed onto the prepared Pd-Cu surface, and formate was generated. Next, hydrogen was exposed on formate/Pd-Cu. These process were observed by XPS.Analysis of the results and their interpretation will be presented in a lecture.

2-Cyanopyridine (2CP) + CeO₂ is highly active as a strong base catalyst. According to DFT calculations, it is considered that negative charge on the cyano group of 2CP increases when it is adsorbed on the surface of CeO₂, and that it becomes a strongly basic site. In this research, XPS measurements of CeO₂(111) surfaces were performed under the presence of 2CP gas. It was shown that interactions with the surface of CeO₂ cause an increase in negative charge on the nitrogen of the cyano group of 2CP, which is estimated as large as 0.2e.

A summary of our current effort for characterizing functional buried interfaces is presented. Buried interfaces are to be characterized in the presence of the condensed phase covering the interfaces. Operando or in-situ methods for characterization are definitely developed.

The massive growth of the electronics industry has increased the need for new active materials for various applications in electronic devices. Organic ferroelectrics such as Poly (vinylidene fluoride) or PVDF are highly preferred due to its less cost, easy fabrication, less weight and high Curie temperatures (Tc) compared to conventional inorganic ferroelectric materials. The ferroelectric nature and stability of PVDF can be altered by choosing appropriate substrates to fabricate thin films. In our work, we examine graphene as a support substrate for crystallization of PVDF. We expect that graphene lattice has a strong epitaxial interaction with PVDF chains with specific symmetry providing excellent ferroelectric nature with stability because of a lattice match between graphene and PVDF. Hence, piezoresponse force microscopy is used as a novel probe microscopy tool to characterize the ferroelectric properties by polarization writing and reading on the surface of the heterostructures.

We developed a methodology to discriminate chirality of a single molecule on a solid surface based on STM using molecular tips. A chiral molecule was used as a tip molecule to measure electron transport with the sample molecule on a metal substrate. Axially chiral binaphthyl derivative (BINAP) served as sample molecules. A break-junction technique was employed to determine the conductance of the single molecular assembly composed of the tip and sample molecules. It was found that the conductance depends on the stereochemistry of the sample molecule, thereby achieving chiral recognition on a single-molecule basis. It was demonstrated that the lifetime of the molecular assembly reflects its stabilization energy calculated based on density functional theory. Thus, we conclude that the stereoselectivity originates from the diastereomeric interaction between the tip and sample.

In the bioelectronics field, metalloproteins containing metal atoms and having high electrical conductivity are expected to be applied to electronic devices. For understanding the electron transfer process in the device, the absolute energy level protein is required. In this study, the electronic structure of metalloprotein containing copper atoms was successfully observed by High-Sensitivity Ultraviolet Photoelectron Spectroscopy (HS-UPS) that can detect weak signals of sub-ppm order.

Membrane proteins in plasma membranes are functional elements essential for life activities, and artificial lipid membranes imitating plasma membranes are used to investigate their structures and functions. In this study, the membrane protein, bacteriorhodopsin (bR), was incorporated into giant unilamellar vesicles (GUV) of cell size, and the influence of the bR function expression on the membrane mechanical properties was evaluated from microscopic observation. From the comparison of different lipid systems, we aimed to clarify the relationship between bR function which is dependent on the intermolecular interaction with surrounding lipids and the membrane dynamics properties of GUV.

Immobilization of functional molecules on surfaces with controlling the orientations and arrangements is an essential process in developments of various materials and devices for sensing, separation, and others. In this study, using frequency modulation AFM (FM-AFM) in liquid, we revealed that tetraphenylmethane (TPM) molecules which have rigid tetrapod structure form self-assembled monolayers on the surface of HOPG and are promising anchor structures for immobilizing functional groups with perpendicular orientation with respect to the surface. Our results should provide a new choice of immobilization anchor to design molecular-scale structures at the surface of HOPG.

Bimolecular layer of lipids, which are nature-derived amphiphilic molecules, are fundamental structures of biomembranes such as cell membranes. Supported lipid bilayers (SLBs) are lipid bilayer membranes situated at solid-liquid interfaces. SLBs are worth being investigated as biomembrane model systems by means of surface scientific methods, and as behaviors of self-assembled soft matter systems at interfaces. I introduce our recent results relating to the effects of structures and physicochemical properties of solid substrate surfaces on domains and molecular diffusion in SLBs.

Alzheimer's disease (AD) is a disease in which amyloid β (Aβ) peptide aggregate on the surface of brain cells under non-equilibrium interstitial fluid flow. However, the molecular mechanism of AD has not been clarified because previous experiments were done with closed system such as Petri dishes. In the present study, we constructed non-equilibrium microfluidic devise, which clarified that the flow promoted the Aβ aggregation and a collapse of membrane. From our observation, we proposed a new mechanism concerning the Aβ aggregation on the membrane surface and consequent nerve cell collapse under non-equilibrium fluidic condition.

Mitochondria synthesizes ATP as an energy carrier on an inner membrane surface using an energy produced by an oxygen reduction reaction. Many studies focused on simulating changes in material concentrations, however, the surface electrochemical reaction kinetics has remined to be analyzed. We report how a mitochondrion reaction system uses an energy for systems such as reaction barriers and proton pumping.

Redox-active metalloenzymes are immobilized on electrodes, and then potentials are applied to the electrode to initiate enzymatic reactions. In such protein film electrochemistry, transmembrane metalloenzymes have been used and known to show lower enzymatic activity on electrodes because of differences between electrode interface and biological membrane environments. In this work, we report the formation process of an artificial bilayer lipid membrane at metalloenzyme-electrode interfaces, tracked by using surface-enhanced infrared absorption spectroscopy, and the impact of the presence/absence of the bilayer lipid membrane on the electrocatalytic enzymatic activity.

The ocean covers approximately 70% of the earth's surface. Its mean depth is 3,800 meters and the deep sea represents the layer deeper than 200 meters. The deep sea is a high pressure, dark, and cold world, but the hydrothermal vent is the the only exception, where hot and compressed water, sometimes in the supercritical state (Tc = 374°C, Pc = 22.1 MPa), gushes out from the sea floor. Under such extreme conditions, water exhibits properties that are remarkably different from those of ambient water, such as mixing freely with oil. In this lecture, characteristics of the deep-sea hydrothermal vent as a supramolecular reactor and roles that it likely played in the origin of life will be presented.

Energy production is one of the remarkable characteristics of life. Within a cell, biological energy, adenosine triphosphate (ATP), is produced by ATP synthase, which is a membrane protein machinery, using pre-formed membrane potential. Here, we constructed an artificial organelle (AO) using ATP synthase and a photoreactive proton-pump, bacteriorhodopsin (bR). ATP synthase and bR were integrated in a small size liposome. The resulting AO generates a proton gradient by light and drove ATP synthase. The AO produced ATP even inside a micro size vesicle in few mM level. So photosynthesized ATP was consumed as an energy for protein synthesis by coupling with a cell-free protein synthesis system. Interestingly, we also success to photosynthesize parts of AO and observed that the activity of AO was enhanced after the photosynthesis reaction. This result represents that the artificial cell can produce own component by using self-sufficient energy, in the scheme of positive feedback loop.

In this presentation, we discuss the mechanism underlying the bioinertness of cell- and protein-resistant self-assembled monolayers. We attempted to clarify the mechanism by surface force spectroscopy and surface-enhanced infrared absorption spectroscopy. In addition, we introduce our recent activity on designs of biomaterials using techniques of informatics. In particular, we discuss technical issues in the design of biomaterials.

Biomaterials are rapidly being developed as powerful artificial microenvironments to control not only various differential cells but also various stem-cells fate, such as proliferation and differentiation. Our recent advances include biomaterial-based artificial extracellular matrix formed by immobilizing cell-recognizable molecule, growth factors and cytokines. Here, we propose "Cadherin-Matrix Engineering" for new frontier of cell-recognizable biomaterials for construction of "Cell-cooking plate" for ES/iPS cells technology using chimeric proteins of cell adhesion molecules (e.g., E-cadherin, N-cadherin, or VE-cadherin) and biohybrid organs.

We observed the tensile deformation and the pulsed-voltage structural behavior of zirconium nanocontacts, which has hexagonal close-packed structure at room temperature by transmission electron microscopy. Simultaneously, the conductance of the nanocontacts was measured and associated it with observed structures.

Two nanometer-sized platinum-iridium tips were brought into contact in the sample chamber of a transmission electron microscope. Subsequently, by pulling the formed nanocontact, its most constriction region was thinned to the width of one atom, followed by fracture. The variation in the structure and conductance of the nanocontact during the deformation process was investigated in situ; we examined how conductance depends on the contact width.

Using platinum-iridium, which has been widely used as a probe material for scanning probe microscopy, we fabricated single-atom-sharpened probes by a pulse-wave energization method. The fabrication process was observed in situ by high-resolution transmission electron microscopy. We demonstrated the control of the probe shape at the atomic level.

Although the structural control of pure metal nanocontacts by pulsed-voltage energization was performed only for body-centered and closed-packed metals, we attempted the energization to a face-centered cubic metal, i.e., iridium. We demonstrated for the first time that amorphization occurred in the face-centered cubic metal.

Metal nano-contacts (NCs) have been studied by many groups since they show unique physical behaviors due to surface effect and quantum confinement. Among them, the atomic chains formation and their physical properties such as electrical conductance have attracted a great deal of interest because they are ultimate one-dimensional material. However, the mechanical property of atomic chains has not been investigated much although it is closely related with the electrical property and very important for novel microelectronics. In this study, for measure the effective spring constant of Pt atomic chain, we employed a transmission electron microscope (TEM) combined with a frequency-modulation force sensing system, which was used for non-contact atomic force microscopy.We could measure the spring constants of Pt atomic chains suspended between two electrodes for the first time. These results depended on the number of Pt atoms in the chain or the relative position of the Pt atomic chain to the edge structure of the electrode, which was resonalbe theoretically.

Gold nanomaterials are attractive due to their unique physical and chemical properties which make them suitable for various applications. These properties are heavily dependent on the morphology of gold nanomaterials. Halide anions are shape-directing factors during the synthesis of gold nanomaterials. In this study, we report that effects of halide on the formation of gold micro- and nanostructures by electrodeposition while changing the concentration of halides to explore the interplay of halide on the growth mechanism of gold nanomaterials.

We have evaluated mechanical properties of nanostructures by combining elasticity (equivalent spring constant) measurement with frequency modulation atomic force microscopy (FM-AFM) and geometric measurement with transmission electron microscopy (TEM). From the experiments, we found that there is a correlation between the structure of gold nano-contacts, the equivalent spring constants, and the electrical conductance. Equivalent Young's modulus could be determined from the equivalent spring constant that changes as the gold nano-contacts become thinner. I will discuss the dependence of crystal orientation and dimensions on equivalent Young's modulus.

We simultaneously measured the time-evolution of mechanical properties (equivalent spring constant) and electric conductance of gold nanocontacts during their extension using a frequency modulation atomic force microscope (FM-AFM); we examined the correlation between them. The electric conductance of the metal nanocontacts is known to be quantized by the unit of quantization conductance G₀. While the measured equivalent spring constants of gold nanocontacts showed large variations even at the same value of conductance, the variations were classified into several groups. Consequently, the variations were possibly ascribed to the difference in the angle between the crystal axis of gold nanocontacts and the direction of nanocontacts extension.

Titanium dioxide is known for the most promising photocatalyst. However, it shows photoactivity only under ultraviolet light due to its wide band gap. In recent research, reduced black TiO₂ nanoparticles, which were produced by hydrogenation of white TiO₂ nanoparticles with a high H₂ pressure and high temperature, showed high photoactivity by visible light. Although it was suggested that this nanoparticle has the core-shell structure, the cause of the structural change is not known yet. In this presentation, we report on the structural change of black TiO₂, which produced by a new method using atomic hydrogen, by XRD.

In this study, electrical properties of three kinds of Ru dinuclear complexes with different bridging ligand were investigated by atomic force microscopy. Nonlinear I-V characteristics and current hysteresis were observed. It was found that hysteresis increased with slew rate and the slew rate dependence of hysteresis was different according to the kind of complex. In this presentation, the results of statistical analysis of current hysteresis measured with different slew rate, and conduction mechanism will be discussed.

We are developing graphene FET (G-FET) biosensors, which enables one to detect influenza virus (IFV) with high sensitivity. Infection mechanism of IFV is represented by chemically modified G-FETs with sialic acids, which can specifically bind human IFV or avian IFV. When IFV is bound to sialic acids on G-FETs, the surface charge of IFVs leads to a significant change in drain current of G-FETs, demonstrating a successful detection of IFV.

Since the 1980s, DENSO Corporation has been mass-producing on-vehicle sensors using MEMS technology based on the microfabrication technology developed for LSIs. By the 2000s, the MEMS technology became commonly accessible simply by installing the appropriate processing equipment lineup, making it difficult to differentiate ourselves from our competitors. In this situation, we steered our research toward integrating functional materials to MEMS technology and aimed for dramatic improvement in sensor performance. In this talk, I will introduce our collaborative work with AIST on a piezoelectric material ScAlN at this time. The topics include the development history, patenting, device applications of ScAlN.

MEMS(Micro Electro Mechanical System) technology has become an essential technology for modern social infrastructure such as smartphones, automobiles and robots (for industrial use). We have successfully developed a specific sputtering module and deposition process for the film deposition of insulating material such as PZT. We present how we have developed an original and specific sputtering module and advanced process technologies for mass production.

By applying glancing-angle deposition scheme, in which a substrate is deeply tilted with respect to a material flux, we deposited WO₃ films by using a rf sputtering system. The deposited WO₃ films showed a deep crocodile-cracking structure. The cracks resulted in a drastic reduction of the reaction time for electrochromic color changes, and we succeeded to improve the electrochromic response property of the WO₃ films.

One of the reasons for different properties of the films deposited at the different substrate positions in sputter deposition is that argon ions neutralized and obliquely reflected at the target surface are incident on the film surface from oblique direction. In this study, the quantity and energy of the fast argon atoms are evaluated to investigate the effect on film formation, assuming binary collision.

The formation of negative ions and the shift of the plasma potential in Mg-CF₄ direct current reactive sputtering have been investigated by using Langmuir probe measurements. By obtaining the 2nd derivative of probe potential-current curves, it was clearly shown that the negative ions were formed in a high CF₄ concentration discharge; the plasma potential decreased to less than -80 V with increasing CF₄ concentration in the discharge gas. The decrease of the plasma potential is to keep the discharge current in the plasma with a high negative ion concentration. The abnormal behaviors of electronegative direct current discharge have been clarified by the probe measurements. The formation of negative ions and the negative shift of plasma potential cause the resputtering of depositing thin films.

We visualized water networks on Ni(111) by low-temperature noncontact atomic force microscopy (AFM) with higher spatial resolution than scanning tunneling microscopy (STM).

An oxygen molecule has an S = 1 spin because the ground state of O₂ isa triplet state. The spin of O₂ is preserved below 10 K on an Agsurface. The O₂ adsorbed on Ag(111) surface was investigated bylow-energy electron diffraction and scanning tunneling microscopy. Inthis study, we investigated this system by scanning probe microscopy. We discovered the O₂ lattice alignment with Ag(111) lattice andlong-range periodicity not reported in previous studies.

The relationship between the force exerted by a metallic tip of a scanning probe microscope to a single CO molecule on a copper surface and its vibrational energy shifts are investigated by using atomic force microscopy and inelastic electron tunneling spectroscopy based on scanning tunneling microscopy. The experimental results are interpreted by using the theoretical calculation with Vienna Ab initio simulation package.