記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Physical Chemistry C  

The visible light-response plasmonic photocathodes were established by depositing Au nanorod structures on wide band gap semiconductor electrodes. By using Au nanorods showing multicolor response characteristics, we observed the generations of the photocurrent under multicolor light illuminations. Additionally, we successfully estimated the absolute electrochemical potential of the excited electrons through the photoinduced depositions of metal species. Our important finding is that the electrochemical potential of the reactive electrons changes not only with the wavelength of illuminated light but also with the semiconductor substrates. Insights from our current findings can be used to develop highly efficient systems for converting light into energy.

DOI： 10.1021/acs.jpcc.4c03271

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Solid State Electrochemistry  

Increasing the concentration of carbon dioxide gas (CO2) in the atmosphere is a problem that must be addressed in modern society. A promising alternative solution to overcome this problem is to convert CO2 into fuel and value-added chemical compounds such as formic acid (HCOOH). This study addresses this concern by electrochemical method to reduce CO2 using a boron-doped diamond (BDD) electrode-modified SnO-SnO2/Ti3C2Tx material which acts as a catalyst in improving the performance of the working electrode. The SnO-SnO2/Ti3C2Tx material in this study has three various concentrationsof SnO-SnO2/Ti3C2Tx 0.05 g/mL, SnO-SnO2/Ti3C2Tx 0.1 g/mL, and SnO-SnO2/Ti3C2Tx 0.2 g/mL, which were dropped onto the surface of the BDD electrode and characterized using cyclic voltammetry (CV), scanning electron microscope-energy dispersive X-ray (SEM-EDX), and X-ray photoelectron spectroscopy (XPS). Electroreduction of CO2 in this study was able to produce the highest concentration of HCOOH by using a SnO-SnO2/Ti3C2Tx-BDD 0.2 g/mL electrode at a reduction potential of − 0.903 V (vs. NHE). The resulting HCOOH has a concentration of 21.32 ppm with a faraday efficiency of 94.06%. The SnO-SnO2/Ti3C2Tx-BDD electrode was then compared with the bare-BDD and BDD-MXene electrodes at the same reduction potential of − 0.903 V (vs. NHE). The concentration of HCOOH produced by bare-BDD was 7.63 ppm with a faraday efficiency of 63.28% and for BDD-MXene that is 9.81 ppm with a faraday efficiency of 79.87%. Thus, BDD electrode modified with SnO-SnO2/Ti3C2Tx is effective to reducing the overpotential of CO2 electroreduction and producing a higher efficiency of HCOOH. Graphical Abstract: (Figure presented.)

DOI： 10.1007/s10008-024-05983-7

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Physical Chemistry Chemical Physics  

Polycrystalline phosphorus-doped diamond was fabricated by the quartz-tube-type microwave plasma-assisted chemical vapor deposition method. Significantly, red phosphorus was used as a source of phosphorous, instead of PH3. Phosphorus-doped diamond electrodes with hydrogen-terminated and oxygen-terminated surfaces were investigated for the redox reactions of K3[Fe(CN)6] and [Ru(NH3)6]Cl3. The carrier concentration was estimated as 2.1-5.3 × 1018 cm−3 from electrochemical impedance measurements. Polycrystalline phosphorus-doped diamond shows great promise as chemical electrode materials.

DOI： 10.1039/d3cp06018g

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Sensors International  

The uncontrolled use of ciprofloxacin (CIP) has led to increased resistance in patients and potential health issues such as kidney disorders, digestive disorder, and liver complications. This study addresses these concerns by introducing an innovative electrochemical sensor utilizing a screen-printed electrode (SPE) enhanced with a novel rGO-SnO2 nanocomposite for the precise monitoring of CIP concentration. Through square wave voltammetry (SWV), this sensor demonstrates unparalleled sensitivity and accuracy in determining CIP levels. These analyses validated the superior performance of the SPE/rGO-SnO2 electrode, revealing CIP potential range of 0.85–1.50 V with irreversible oxidation reaction and an exceptional signal-to-background (S/B) ratio of 1.91, surpassing the 1.21 ratio achieved by the SPE/rGO electrode. The SPE/rGO-SnO2 electrode also exhibited the highest active surface area (0.0252 cm2), facilitating faster transfer electron. Crucially, the SPE/rGO-SnO2 electrode exhibited an impressively low limit of detection (LOD) at 2.03 μM within a concentration range of 30–100 μM for CIP, setting a new benchmark for sensitivity (9.348 μA/μM) in CIP detection. The %RSD value was less than 5 % indicating that this modified electrodes exhibit good precision and stability. The real-world applicability of this developed methods was exemplified through its successful implementation in the analysis of river water and milk, achieving remarkable recovery rates of 101.2 % and 97.7 %, respectively. Consequently, the SPE modified with rGO-SnO2 nanocomposite emerges as a highly promising and effective tool for precise and sensitive CIP measurement, offering unparalleled performance metrics and opening avenues for enhanced environmental and health monitoring.

DOI： 10.1016/j.sintl.2023.100276

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記述言語：英語   掲載種別：論文集(書籍)内論文   出版者・発行元：Diamond Electrodes: Fundamentals and Applications  

BDD electrode was utilized as the cathode for the electrochemical CO2 reduction due to its high hydrogen overpotential and high stability. Electroreduction of CO2 is one of the ways to convert CO2 into useful compounds which can be used in industrial fields and can be used as fuels. The efficiency or selectivity for the production of CO2 reduction products can be affected by electrode materials and electrolysis conditions. BDD electrode is inert, so formic acid production was predominant. However, we could also produce various kinds of products from CO2 by optimizing the electrode itself or electrolysis conditions. Many kinds of BDD electrodes were used such as BDD electrodes with various boron doping level, BDD electrodes with sp2 carbon impurities and BDD electrodes modified with metal particles electrochemically. Electrolysis conditions were also optimized such as the applied potential, applied current, catholyte and anolyte. In this chapter, the electrochemical CO2 reduction using BDD electrodes or using metal-modified BDD electrodes was described.

DOI： 10.1007/978-981-16-7834-9_10

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