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The optimal conditions for fabricating a screen-printed diamond electrode for the sensitive detection of l -cysteine (Cys), a non-essential amino acid, were investigated. As-grown (AG-), hydrogen-terminated (H-) and oxygen-terminated boron-doped diamond powders (O-BDDP) were prepared, and BDDP-printed electrodes were fabricated using BDDP-containing inks. Comparing the linear sweep voltammograms of Cys at AG-BDDP-, H-BDDP-, and O-BDDP-printed electrodes, among the three samples, the H-BDDP-printed electrode was found to be the most suitable for the sensitive detection of Cys at low concentrations, showing a steep slope in its calibration curve and a low background current density. In addition, the H-BDDP-printed electrode exhibited a lower limit of detection (0.620 μM) and a more negative oxidation peak potential (+0.663 V vs. Ag/AgCl) and wider linear concentration range (1–194 μM) than a H-boron-doped diamond (BDD) thin-film electrode. It is thought that a slight amount of sp2 carbon on the BDDP contributed to these optimal properties. Using the H-BDDP-printed electrode, Cys was detected in a solution containing electroactive interferents (glutathione and methionine) with a recovery of 86–104%. Therefore, it was concluded that the H-BDDP-printed electrode can be used as a highly sensitive and disposable electrochemical sensor for Cys detection.

This study investigates the effect of chemical surface termination on the electrochemical characteristics of boron-doped diamond powder (BDDP). The aim is to realize highly sensitive electrochemical detection of ciprofloxacin (CIP) on BDDP-printed electrodes. To this end, we prepared oxygen-terminated BDDP (O-BDDP) and hydrogen-terminated BDDP (H-BDDP), and mixed them with an insulating polyester (PES) resin binder to obtain BDDP ink for the printed electrode. Scanning electron microscopy of the BDDP-printed electrodes revealed that the O-BDDPs were partially covered with PES resin, while the H-BDDPs were entirely covered with resin. This structural difference might explain the lower charge-transfer resistance of the Ru(NH3)62+/3+ redox reaction at the O-BDDP-printed electrode than at the H-BDDP-printed electrode. The slope of the calibration curve of the linear sweep voltammogram of CIP was steeper at the O-BDDP-printed electrode than at the H-BDDP-printed electrode and the O-BDD thin-film electrode, and was similar to that at the H-BDD thin-film electrode. Using the O-BDDP-printed electrode, we determined the CIP in artificial buffer-diluted urine in the concentration range 1–30 μM with a recovery of 107%. We conclude that the O-BDDP-printed electrodes provide a highly sensitive and disposable electrochemical sensor for CIP detection.

Boron-doped diamond (BDD) electrodes have a wide potential window and can produce ozone by water electrolysis at high voltage. Though ozone has strong oxidative power (standard oxidation potential: 2.07 V vs. NHE), it cannot decompose certain types of recalcitrant organic matter completely. We developed an advanced oxidation process (AOP), in which hydroxy radicals with stronger oxidative power (standard oxidation potential: 2.85 V vs. NHE) are formed using a combination of ozone, photocatalyst, and UV. In this study, we fabricated a mesoporous TiO2/BDD hybrid electrode and examined its potential for AOPs. A synergetic effect between electrochemical water treatment and photocatalytic water treatment was observed with the hybrid electrode that did not occur with the BDD electrode.

Here, we report the first synthesis of polycrystalline boron-doped diamond (BDD) by an In-liquid microwave plasma CVD (IL-MPCVD) process from a mixture of alcohols and boron trioxide (B2O3). We simultaneously achieved high growth rates (up to 287 μm/h) and high boron concentrations (up to 7 × 1021 cm−3). We examined the growth mechanism and show that water generated by dissolution of B2O3 in the alcohol is key to rapid growth of BDD. Even with the same C:H:O ratio, diamond growth rate and nucleation density drastically decreased by addition of water. Water has a strong etching effect, which shifts diamond to grow in carbon rich conditions. Finally, we evaluated the as-grown BDD film as a diamond electrode. Our IL-MPCVD-grown BDD showed electrochemical properties comparable to those of BDD grown by the conventional CVD process in terms of its potential window (3.2 V) and peak separation (85 mV) in 1 mM K3[Fe(CN)6]. Owing to the high growth rate, IL-MPCVD is an effective technique for synthesizing BDD.

Herein, a conductive boron-doped nanodiamond (BDND) particle is prepared as an electrode material for an aqueous electric double-layer capacitor with high power and energy densities. The BDND is obtained by depositing a boron-doped diamond (BDD) on a nanodiamond particle substrate with a primary particle size of 4.7 nm via microwave plasma-assisted chemical vapor deposition, followed by heat treatment in air. The BDND comprises BDD and sp

In this research work, we reported the synthesis of a spherical-shaped bismuth vanadate (BiVO4) photocatalyst using a cost-effective, simple, chemical hydrothermal method and studied the effect of deposition temperatures on the structural, morphological, optical properties, etc. The XRD result confirmed the monoclinic scheelite phase of BiVO4. An XPS study confirmed the occurrence of Bi, V, and O elements and also found that Bi and V exist in +3 and +5 oxidation states, respectively. SEM micrographs revealed the spherical-shaped morphology of the BiVO4 photocatalyst. Optical investigation showed that the bandgap of the BiVO4 photocatalyst varied between 2.25 and 2.32 eV. The as-synthesized BiVO4 photocatalyst was used to study the photocatalytic degradation of crystal violet (CV) dye under visible light illumination. The photocatalytic degradation experiment showed that the degradation percentage of crystal violet dye using BiVO4 reached 98.21% after 120 min. Mineralization of crystal violet dye was studied using a chemical oxygen demand analysis.

We report a simple room-temperature synthesis route for increasing the reactivity of a TiO2 photocatalyst using a solution plasma process (SPP). Hydrogen radicals generated from the SPP chamber interact with the TiO2 photocatalyst feedstock, transforming its crystalline phase and introducing oxygen vacancy defects. In this work, we examined a pure anatase TiO2 as a model feedstock because of its photocatalytic attributes and well-characterized properties. After the SPP treatment, the pure anatase crystalline phase was transformed to an anatase/brookite heterocrystalline phase with oxygen vacancies. Furthermore, the SPP treatment promoted the absorption of both UV and visible light by TiO2. As a result, TiO2 treated by the SPP for 3 h showed a high gaseous photocatalytic performance (91.1%) for acetaldehyde degradation to CO2 compared with the activity of untreated TiO2 (51%). The SPP-treated TiO2 was also more active than nitrogen-doped TiO2 driven by visible light (66%). The overall photocatalytic perfor...

Platinum nanoparticle-supported boron-doped diamond powder (Pt/BDDP) was prepared and investigated as a durable polymer electrolyte fuel cell (PEFC) cathode catalyst. The use of the nanocapsule method enabled dense deposition of Pt nanoparticles (2–5 nm in size) on a boron-doped diamond (BDD) powder

We focused on a micro diamond (MD) particle with the highest thermal conductivity among existing materials and aimed to make a MD/copper composite material by electroplating. However, copper is naturally non-wetting with MD due to its chemical incompatibility, leading to weak interfacial bonding and high thermal resistance. We improved the wettability between MD and copper functionalized by the amino group on the MD using a photocatalytic reaction. The functionalization of the diamond surface by amino groups was achieved by treating the MDs in a 3-aminopropyltrimethoxysilane-containing solution. The amino group functionalized MD was dispersed in the electroplating bath, where copper was deposited on the MD. As a result, the composite material of amino group functionalized MD assisted by photocatalyst and copper improved their interfacial affinity and exhibited the high thermal conductivity of 595 W/m K.

Techniques for large-area pattern formation on polymeric substrates are important for fabricating a large variety of functional devices, such as flexible electronics, tunable optical devices, adhesives, and so on. The present study demonstrates a method for pattern formation on poly(dimethylsiloxane) that involves grafting methacrylate polymers through photo-initiated polymerization. The influence of substrate stiffness and monomers type on pattern formation was investigated. Firstly, the stiffness of the substrate was found to affect the topology of the patterns produced. The gap width of convex regions of the pattern was enlarged with decreasing stiffness. It was found that the gap width trended in a manner that was consistent with previous reports, but in this study, relatively large gap widths were observed compared with those from previous studies. Secondly, it was revealed that the solubility of the monomer in the poly(dimethylsiloxane) precursor was the dominant factor in determining whether or not pattern formation occurred. When using insoluble monomers (glycidyl methacrylate and benzyl methacrylate), characteristic patterns were observed. It is speculated that intermolecular attractive forces between the grafted polymers induce lateral aggregation on the substrate, resulting in buckling instability of the grafted polymer layer caused by a mismatch in the equilibrium between the grafted polymer layer and the substrate. Copyright © 2017 John Wiley & Sons, Ltd.

A boron-doped diamond (BDD) electrode with a large specific surface area was fabricated by formation of a hierarchical nanostructure. A BDD thin film was deposited on a silicon pillar array substrate fabricated using photolithography to obtain a BDD pillar array (BDD-PA). The BDD-PA was subjected to a two-step thermal treatment to form dense pores on the surface (P-BDD-PA). The P-BDD-PA was then treated by reactive ion etching (RIE) to form nanowhiskers on the surface (P-BDDW-PA). The combination of these structures (pillar array, pores and nanowhiskers) enabled enhanced double-layer capacitance (ca. 2800 μF cm − 2 ) based on the enlarged specific surface area without narrowing of the potential window (ca. 3 V) in an aqueous electrolyte. The combination of the two-step thermal treatment and RIE treatment should be an effective post-treatment method for enhancement of the capacitance of porous BDD materials consisting of micrometer-sized structures without significant increase of the time constant.

Herein, a conductive boron-doped nanodiamond (BDND) particle is prepared as an electrode material for an aqueous electric double-layer capacitor with high power and energy densities. The BDND is obtained by depositing a boron-doped diamond (BDD) on a nanodiamond particle substrate with a primary particle size of 4.7 nm via microwave plasma-assisted chemical vapor deposition, followed by heat treatment in air. The BDND comprises BDD and sp2 carbon components, and exhibits a conductivity above 1 S cm−1 and a specific surface area of 650 m2 g−1. Cyclic voltammetry measurements recorded in 1 M H2SO4 at a BDND electrode in a two-electrode system shows a capacitance of 15.1 F g−1 and a wide potential window (cell voltage) of 1.8 V, which is much larger than that obtained at an activated carbon electrode, i.e., 0.8 V. Furthermore, the cell voltage of the BDND electrode reaches 2.8 V when using saturated NaClO4 as electrolyte. The energy and power densities per unit weight of the BDND for charging–discharging in 1 M H2SO4 at the BDND electrode cell are 10 Wh kg−1 and 104 W kg−1, respectively, and the energy and power densities per unit volume of the BDND layer are 3–4 mWh cm−3 and 10 W cm−3, respectively. Therefore, the BDND is a promising candidate for the development of a compact aqueous EDLC device with high energy and power densities.

Titanium dioxide (TiO2) has been widely used as a catalyst material in different applications such as photocatalysis, solar cells, supercapacitor, and hydrogen production, due to its better chemical stability, high redox potential, wide band gap, and eco-friendly nature. In this work TiO2 thin films have been deposited onto both glass and silicon substrates by the atmospheric pressure plasma jet (APPJ) technique. The structure and morphological properties of TiO2 thin films are studied using different characterization techniques like X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and field emission scanning electron microscopy. XRD study reveals the bronze-phase of TiO2. The XPS study shows the presence of Ti, O, C, and N elements. The FE-SEM study shows the substrate surface is well covered with a nearly round shaped grain of different size. The optical study shows that all the deposited TiO2 thin films exhibit strong absorption in the ultraviolet region. The oleic acid photocatalytic decomposition study demonstrates that the water contact angle decreased from 80.22 to 27.20° under ultraviolet illumination using a TiO2 photocatalyst.

A coating was developed by controlling its glass transition temperature (Tg). This coating attained its highest Tg value in wet conditions (wet Tg) of higher than 100 °C, and maintained its adhesion on stainless steel even after immersion in boiling water. When this coating material was applied to a conventional two-component epoxy structural adhesive as a metallic primer, it improved the primer adhesion durability on the stainless steel sheet in water significantly, even if it was not chemically modified (without pretreatment). This indicated that a relative weak hydrogen bond between the hydroxyl group of the epoxy network and a surface hydroxyl group of the oxide layer of the stainless steel could be sufficient to prevent water penetration into the interface if the thermal mobility of the epoxy network is restrained. An investigation by X-ray photoelectron spectroscopy (XPS) indicated an interaction between a primer amino-group component and the metallic surface accompanied by proton transfer. However, the thermal mobility of the epoxy network could be the most important factor in its adhesion in wet conditions.

The surface of nanodiamond (ND) particles was modified with 1-octadecene via a simple thermal reaction to obtain octadecyl-modified ND. Fourier transform infrared spectroscopy and thermogravimetric analysis results indicated that octadecyl groups were successfully introduced onto the ND surface. The amount of the octadecyl groups on the ND surface was observed to increase with increasing reaction time and to eventually saturate. A bead-milling process, which enabled disaggregation of NDs in 1-octadecene, was observed to increase the amount of octadecyl groups adsorbed onto the ND surface. The estimated surface coverage was as high as 2.2 × 1014 molecules cm−2, which corresponds to submonolayer level. Dispersion tests revealed that the octadecyl-modified ND particles exhibit hydrophobic/lipophilic character, whereas the oxidized ND (before surface modification with 1-octadecene) exhibited good dispersibility in water. Particle size distribution analysis by dynamic light scattering revealed that the particle size of the octadecyl-modified ND in chloroform, a non-polar solvent, was ca. 20 nm. Thus, the present method should be useful for fabricating NDs that can be dispersed in non-polar organic solvents and should facilitate the expansion of the application fields of ND.

Primary challenges in electrochemical CO2 reduction lie with its product selectivity and competitive hydrogen evolution reaction (HER). Therefore, selective CO2 reduction with less hydrogen evolution or without any hydrogen evolution is very essential for industrial interests. In this study, we report a selective electrochemical CO2 reduction at a boron-doped diamond electrode modified with Cu nanoparticles in ionic liquid. In addition to the improved product selectivity, control of the competitive HER was also achieved in this work.

Diamond synthesis and its morphology by in-liquid plasma chemical vapor deposition (CVD) method are investigated in this study. Diamond films were grown on Si substrates from mixed alcohol solution. Very high growth rate of 170 μm/h was achieved by this method. Microcrystalline and nanocrystalline diamond films were formed in different conditions. In the case of microcrystalline film, the shapes of diamond grains depend on the location in the film. All morphological differences in this study can be explained by the same mechanism of conventional gas phase CVD method. It means diamond morphology by in-liquid plasma CVD method can be controlled by process parameters as well as gas phase CVD method.

Understanding the fundamentals of photoelectrocatalytic (PEC) biomolecular oxidation benefits the development of next-generation PEC biosensors. In this work, single-step electrospun titanium-di-oxide–gold (TiO2–Au) hybrid nanofibers (HNF) are reported as being a potential candidate for PEC glutathione (GSH) bioanalysis. The chemical environment of TiO2 and TiO2–Au HNFs were studied with X-ray photoelectron spectroscopy and found to have a strong electronic interaction between TiO2 and the Au nanoparticles (NPs). The PEC measurements revealed that the intramolecular backbone hydrogen bonding of GSH molecules predominantly contributes highly active Au–GSH bio-nano interfaces, which facilitate the PEC oxidation rate of GSH and thus enhance the photocurrent. Furthermore, the Au NPs present act as auxiliary electron transport channels resulting in enhanced charge collection at the external circuit. As a result, the TiO2–Au electrode generated a two-fold higher photocurrent density of ∼84.4 μA cm−2 in the presence of 0.5 mM GSH, where the pristine TiO2 NFs displayed only a negligible influence. Likewise, the TiO2–Au HNF electrode showed a higher sensitivity of 0.002 mM and a wide linear detection range between 0.022 mM and 0.7 mM, with a superior selectivity towards GSH bioanalysis over ascorbic acid and glucose at −0.33 V (versus silver/silver chloride) than that obtained with pristine TiO2. The implications of these findings towards the development of a next-generation PEC biosensor are discussed.

There is a need for highly efficient photocatalysts, particularly for water purification. In this study, we fabricated a mesoporous TiO2 thin film on a boron-doped diamond (BDD) layer by a surfactant-assisted sol-gel method, in which self-assembled amphiphilic surfactant micelles were used as an organic template. Scanning electron microscopy revealed uniform mesopores, approximately 20 nm in diameter, that were hexagonally packed in the TiO2 thin film. Wide-angle X-ray diffraction and Raman spectroscopy clarified that the framework crystallized in the anatase phase. Current&ndash, voltage (I&ndash, V) measurements showed rectification features at the TiO2/BDD heterojunction, confirming that a p&ndash, n hetero-interface formed. The as-synthesized mesoporous TiO2/BDD worked well as a photocatalyst, even with a small volume of TiO2 (15 mm &times, 15 mm &times, c.a. 1.5 &micro, m in thickness). The use of deep UV light (&lambda, = 222 nm) as a light source was necessary to enhance photocatalytic activity, due to photo-excitation occurring in both BDD and TiO2.

A two-step thermal treatment method was developed for the fabrication of porous conductive boron-doped diamond (BDD) electrodes. The first step involved graphitization of the BDD thin film surface to form a fine microstructure by heating in an argon atmosphere at 1000 °C. The second step was removal of the graphitic components by oxidation in air at 425 °C. The heat treatment resulted in the formation of dense pores with several tens to several hundred nanometer sizes or smaller on the BDD surface. The pore formation mechanism was discussed by microscopic observation of the (1 1 1) and (1 0 0) crystal facets on the treated BDD surface. The porous BDD electrode exhibited a double-layer capacitance ( C dl ) of ca. 140 μF cm −2 , which was estimated from cyclic voltammetry (CV) and galvanostatic measurements in an aqueous electrolyte. This C dl value was approximately 40 times larger than that for the as-deposited BDD electrode, while the potential window remained wide at ca. 3 V.

Micrometer-sized porous diamond spherical particles (PDSPs) were fabricated from nanodiamond (ND) particles using spray drying and microwave plasma-assisted chemical vapor deposition (MPCVD). Nitrogen gas sorption measurement revealed that the PDSP fabricated from 5 nm detonation ND particles had a Brunauer–Emmett–Teller (BET) surface area of ca. 300 m 2 g − 1 and a narrow pore diameter distribution around 10 nm. Nitrogen sorption analysis of PDSP fabricated from various ND particle sizes (diameters from 20 to 50 nm) showed that the BET surface area decreased (200–85 m 2 g − 1 ) and the average pore diameter increased (4.6–9.3 nm) as the ND diameter increased from 20 to 50 nm. Calculation with a simple model revealed that the pores of the PDSP were derived from the interparticle space of the NDs. The PDSP was durable to immersion in aqueous solutions of HF and NaOH, which indicates the extremely high chemical stability of the diamond-based mesoporous material. The PDSP surface was modified with octadecyl groups using a photochemical method. A column packed with the modified PDSP was successfully employed in a reverse phase high performance liquid chromatography (HPLC) column, and the successful separation of organic compounds was demonstrated with a water/acetonitrile mixture mobile phase.

The influence of low pressure oxygen (O2) and argon (Ar) gas plasma modification of polyimide film on the adhesion to an alloy plating layer made from chromium (Cr) and nickel (Ni) was investigated. X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) were employed, respectively, to estimate the chemical and morphological status of the modified polyimide surface. Attenuated total reflectance-Fourier transform infrared (ATR-IR) spectroscopy and scanning electron microscopy (SEM) were also employed to determine the fracture mode during an adhesion durability test. The results indicated that O2 plasma treatments generated carboxyl groups, but an excess of carboxyl groups could oxidize the Cr at the interface at elevated temperatures, which led to a loss of adhesion.

Cobalt polypyrrole-supported carbon (CoPPy/C) has been expected to be a low-cost alternative to platinum catalysts for proton exchange membrane fuel cell (PEMFC) cathode. Although the catalytic activity of the CoPPy/C is relatively high, improvement of the durability to long-term use is still challenging problem. In order to know the deterioration mechanism of PEMFC cathode, dynamic-secondary ion mass spectrometry (D-SIMS) was used in this study for analysis of cathode catalyst layer/solid electrolyte membrane interfaces before and after an aging test. The depth profile of cobalt species across the interface of a CoPPy/C cathode was significantly changed after the aging test. From the depth profile of cobalt in the CoPPy/C catalyst, it is suggested that the cobalt species may transfer in the membrane along with the flow of the back diffusion water.

Liposome was synthesized by using mixture of dipalmitoylphosphatidylcholine and cholesterol in the ultrapure water or physiological saline. Phase transformation temperature and vibrational mode of dipalmitoylphosphatidylcholine molecule were detected by using transmission Fourier-transform infrared spectroscopy for aqueous solution, which we developed. The liposomes were fixed on an amorphous carbon mesh for ultra-high resolution transmission electron microscopy observation and stained with platinum thymidine blue. As-prepared liposomes reinforced with cholesterol were spherical in shape with size larger than 100 nm in diameter and still stable in the vacuum. Under the strong electron irradiation condition, the solution enclosed in the liposomes became unstable and then collapsed. On the other hand, the liposome synthesized in the physiological saline sometimes contains crystallized salt. As a result, the liposome shows proper strength to hold wet material in itself in a vacuum and can be used for the transmission electron microscopy observation.

Platinum nanoparticle-embedded porous diamond spherical particles (PtNP@PDSPs), as an active and stable catalyst, were fabricated by spray-drying of an aqueous slurry containing nanodiamond (ND) particles, platinum nanoparticles (PtNP), and polyethylene glycol (PEG) to form ND/PtNP/PEG composite spherical particles, followed by removal of PEG and a short-time diamond growth on the surface. The average diameter of the PtNP@PDSPs can be controlled in the range of 1–5 μm according to the spray-drying conditions. The Brunauer-Emmett-Teller (BET) surface area and average pore diameter of the PtNP@PDSPs were estimated to be ca. 170–300 m2 g−1 and ca. 4–13 nm, respectively. When ND with the size of 20–30 nm was used, the size of PtNP in the PtNP@PDSP was almost unchanged at 5–6 nm even after high temperature processes and reuse test for catalytic reaction, showing stable supporting. The catalytic activity of the PtNP@PDSPs for the dehydrogenation of cyclohexane was higher than that for a Pt/C catalyst, which is attributed to the stable PtNP support by the three-dimensional packing of ND and efficient mass transfer via the interconnected through-hole pores in the PDSPs.

Competitive hydrogen evolution and multiple proton-coupled electron transfer reactions limit photoelectrochemical CO2 reduction in aqueous electrolyte. Here, oxygen-terminated lightly boron-doped diamond (BDDL) thin films were synthesized as a semiconductor electron source to accelerate CO2 reduction. However, BDDL alone could not stabilize the intermediates of CO2 reduction, yielding a negligible amount of reduction products. Silver nanoparticles were then deposited on BDDL because of their selective electrochemical CO2 reduction ability. Excellent selectivity (estimated CO:H2 mass ratio of 318:1) and recyclability (stable for five cycles of 3 h each) for photoelectrochemical CO2 reduction were obtained for the optimum silver nanoparticle-modified BDDL electrode at −1.1 V vs. RHE under 222-nm irradiation. The high efficiency and stability of this catalyst are ascribed to the in situ photoactivation of the BDDL surface during the photoelectrochemical reaction. The present work reveals the potential of BDDL as a high-energy electron source for use with co-catalysts in photochemical conversion.

Semiconductor photocatalysis driven by electron/hole has begun a new era in the field of solar energy conversion and storage. Here we report the fabrication and optimization of TiO2/BDD p-n heterojunction photoelectrode using p-type boron doped diamond (BDD) and n-type TiO2 which shows enhanced photoelectrochemical activity. A p-type BDD was first deposited on Si substrate by microwave plasma chemical vapor deposition (MPCVD) method and then n-type TiO2 was sputter coated on top of BDD grains for different durations. The microstructural studies reveal a uniform disposition of anatase TiO2 and its thickness can be tuned by varying the sputtering time. The formation of p-n heterojunction was confirmed through I-V measurement. A remarkable rectification property of 63773 at 5 V with very small leakage current indicates achieving a superior, uniform and precise p-n junction at TiO2 sputtering time of 90 min. This suitably formed p-n heterojunction electrode is found to show 1.6 fold higher photoelectrochemical activity than bare n-type TiO2 electrode at an applied potential of +1.5 V vs SHE. The enhanced photoelectrochemical performance of this TiO2/BDD electrode is ascribed to the injection of hole from p-type BDD to n-type TiO2, which increases carrier separation and thereby enhances the photoelectrochemical performance.

A disposable and sensitive screen-printed electrode was fabricated on a polyimide film substrate using an ink containing conductive boron-doped diamond powder (BDDP). The BDDP-printed electrode exhibited a wider potential window and lower background current in an aqueous electrolyte than a carbon-printed electrode, and the signal-to-background ratio of the redox peak for ferri/ferrocyanide was greater at the BDDP-printed electrode than at the carbon-printed electrode. Electrode fouling during potential cycling in the presence of dopamine was found to be less at the BDDP-printed electrode than at the carbon-printed electrode. Thus the BDDP-printed electrode should be useful as a disposable, sensitive and low-fouling platform for bio- and electrochemical sensors compared to conventional carbon-printed electrodes. Keywords: Boron-doped diamond (BDD) electrode, Screen-printed electrode, Electroanalysis

Search for non-platinum metal catalyst as the cathode of polymer electrolyte membrane fuel cell (PEMFC) is an important subject in the recent fuel cell research. Macromolecule–metal complexes with macrocyclic ligands such as porphyrin and macromolecular ligands such as polypyrrole, all of which contain four nitrogen donors (Co-N4 chelates) and are adsorbed on carbon, were prepared and heat-treated in the hope that they can be an alternate to the conventional carbon-supported platinum catalyst. Carbon-supported cobalt (5,10,15,20-tetraethylporphyrin) (HT-CoTEtP/C), poly(cobalt (5-mono(3-thienyl)-10,15,20-triethylporphyrin)) (HT-P(CoM3ThTEtP)/C), and cobalt-(polypyrrole) (HT-CoPPy/C) were chosen as candidate heat-treated catalysts based on the electrocatalytic activity tests on the prepared macromolecule–metal complexes. The rotating ring-disk method revealed that these catalysts reduce oxygen mainly with four electrons. Characterization using X-ray photoelectron spectroscopy showed that the catalysts maintain the Co-N4 chelate structure, strongly suggesting a major contribution of the Co-N4 chelate to the four-electron reduction of oxygen. Membrane electrode assemblies (MEAs) of PEMFCs were then constructed using HT-CoTEtP/C, HT-P(CoM3ThTEtP/C), and HT-CoPPy/C as the cathode catalysts and the current density-cell voltage and current density-power density relationships were examined for the PEMFC. HT-CoTEtP/C exhibited a much higher performance than the other macromolecule–metal complexes. Although the open circuit voltage and power density values of the PEMFCs were lower than those of the conventional carbon supported platinum catalyst, the power density per unit metal weight was almost comparable for the cobalt and platinum catalysts. Copyright © 2011 John Wiley & Sons, Ltd.

超臨界二酸化炭素(scCO2)を溶媒として用いた化学酸化重合法によりピロール(Py)を重合し，導電性高分子であるポリピロール(PPy)を得た．反応開始剤として，scCO2 に可溶なビストリフルオロアセトキシヨードベンゼン(BTI)を用いることで，助溶媒等の有機溶媒を必要としない溶媒フリーな導電性高分子の重合プロセスとした．得られた PPy の形状を走査型電子顕微鏡(SEM)および動的光散乱(DLS)により評価した．得られた形状と実験条件の関係から粒子径分布幅の狭いナノ粒子となる条件を決定し，PPy ナノ粒子の合成を検討した．この結果，Py 0.1 M，BTI 0.005 M，圧力 20 MPa，温度 40℃，反応時間 1 h を最適条件とした．この反応条件において，50～90 nm 程度の粒子径分布幅の狭いナノ粒子が得られることが明らかとなった．さらに，ピロール誘導体の一つである 3-ヘプチルピロール(HPy)についてもナノ粒子の合成に成功した．

エンジニアリングプラスチックとして知られるポリ(2,6-ジメチル-1,4-フェニレンエーテル)(PPE)は，2,6-ジメチルフェノールの酸化重合により得られる．筆者らは最近，重合機構の解析により，重合度の異なる 2 種類の PPE 類からブロック共重合体が生成することを見いだした．具体的には，PPE(Mn=2.2×104, Mw/Mn=2.5)とオリゴ(2-エトキシカルボニル-6-メチル-1,4-フェニレンエーテル)(Mn=7.5×103, Mw/Mn=1.5)を溶解し，酸化剤として酸化銀(I)を添加し反応させた．反応液を任意の時間で採取し，時間経過に伴う分子量変化を GPC により追跡した．反応開始前に見られた GPC ピークの数は反応時間の経過とともに減少し，単一のピークが融合した(Mn=1.5×104, Mw/Mn=2.2)．140 時間後に GPC ピークは単峰性を示し，再沈殿精製後の NMR, DSC を用いた解析によりブロック共重合体の生成が示された．トリフルオロ酢酸によりエステルを加水分解し，カルボン酸置換 PPE ブロック共重合体を得た．PPE とオリゴ(2,6-ジフェニル-1,4-フェニレンエーテル)(Mn=8.5×103, Mw/Mn=1.3)を反応させ，得られたブロック共重合体の一方のユニットへ選択的にスルホン酸基を導入し，スルホン酸置換 PPE ブロック共重合体を合成した．固体高分子形燃料電池電解質の膜材料としての応用を期待して，膜劣化やイオン交換容量(IEC)など膜特性を評価した．スルホン酸置換 PPE ブロック共重合体の微細相分離構造を明らかにし，高い IEC を示す膜を得た．

アセトニトリルを助溶媒とした超臨界二酸化炭素(scCO2/AN)中において，アニリンを電解重合し，導電性高分子であるポリアニリンを得た．まず，超臨界二酸化炭素に助溶媒を加え，アニリン・支持電解質・トリフルオロ酢酸(TFA)を加え，相図を作製した．この相図より，均一相の条件において各圧力条件での電解重合を行い，得られるサイクリックボルタモグラムから電気化学反応特性を議論した．得られた重合膜の表面観察をレーザー顕微鏡および原子間力顕微鏡により測定した．得られた生成膜の特徴と実験条件の関連から，緻密な重合膜を得るための条件を決定し，緻密な平滑膜の合成を検討した．その結果，最適条件はアニリン 0.04 M, TBAPF6 0.04 M, AN 16 vol%, TFA 0.04 M，圧力 10 MPa が最適条件であった．この重合条件では，有機溶媒中で合成した膜に比べ，より平滑かつ均一な重合膜が得られることが明らかとなった．これにより，scCO2 中での電解重合法が電解合成に幅広く応用できることが示された．

Surface-modified mesoporous silicas (MSs) were investigated for recyclable adsorption of an endocrine disrupter, bisphenol A (BPA). Surface-modified MSs were prepared by (i) post-synthesis surface modification of MSs using surface hydroxyl groups and organosilanes (m-MS) and by (ii) co-condensation of tetraethoxysilane and the corresponding organosilanes (d-MS). Infrared measurements indicated that organic groups mainly existed on the surface of m-MS, which resulted in a surface characterized by high hydrophobicity. Both organic groups and isolated hydroxyl groups existed on the surface of d-MS, resulting in both hydrophobicity and hydrophilicity on the surface. The amount of BPA adsorbed on surface-modified MSs per organic group was similar for m-MS and d-MS, however, the d-MS established equilibrium for BPA adsorption faster than m-MS, as measured by UV-vis spectra. A larger amount of BPA per surface area could be adsorbed on carbon materials than on the surface-modified MSs, however, the regeneration of carbon materials by washing could not be done easily. The surface-modified MSs retain adsorption capacity for BPA after several regeneration cycles, demonstrating that the surface-modified MSs are effective recyclable adsorbents of the endocrine disrupter, bisphenol A.

Aluminosilicate mesoporous materials (AIMS) were synthesized by two different methods. In "stepwise direct synthesis" of AIMS, sodium aluminate was added at the second ageing after the first ageing of sodium silicate and surfactant mixtures with the purpose of Al incorporation on or near the surface region of the pore wall in order to provide easily accessible ion-exchange sites. Most of the Al atoms in the AIMS prepared by the "stepwise direct synthesis" were present as tetrahedral-coordinated framework in the resulting mesostructured aluminosilicate of hexagonal symmetry. FT-IR spectra of pyridine adsorbed on the AIMS revealed that the AIMS prepared by the "stepwise direct synthesis" had a higher ratio of Bronsted acid sites to Lewis acid sites than the AIMS prepared by the conventional direct synthesis. Copper ion-exchanged AIMS (Cu/AlMS) catalysts were evaluated for NO reduction by CO. The Cu/AlMS catalyst prepared by the "stepwise direct synthesis" demonstrated catalytic activity for NO reduction without an aggregation of Cu species.

Carbon nanoparticles modified with a polypyrrole (PPy) film, impregnated with a solution of a cobalt salt, and heat-treated under an inert atmosphere at 600−700 °C are a good electrocatalyst for the four-electron reduction of O2.