タングステン及びモリブデンを含む規則化ペロブスカイト型酸化物の合成、結晶構造と触媒特性

長崎大学学位論文 学位記番号:博(海)甲第182号 学位授与年月日:平成12年3月31

Metal-organic framework derived hierarchical porous TiO2 nanopills as a super stable anode for Na-ion batteries

Hierarchical porous TiO2 nanopills were synthesized using a titanium metal-organic framework MIL-125(Ti) as precursor. The as-synthesized TiO2 nanopills owned a large specific surface area of 102 m2/g and unique porous structure. Furthermore, the obtained TiO2 nanopills were applied as anode materials for Na-ion batteries for the first time. The as-synthesized TiO2 nanopills achieved a high discharge capacity of 196.4 mAh/g at a current density of 0.1 A/g. A discharge capacity of 115.9 mAh/g was obtained at a high current density of 0.5 A/g and the capacity retention was remained as high as 90% even after 3000 cycles. The excellent electrochemical performance can be attributed to its unique hierarchical porous feature

Mesoporous titania nanotubes: their preparation and application as electrode materials for rechargeable lithium batteries

Mesoporous titania nanotubes with tunable dimension have been fabricated within the pores of alumina membranes by a simple sol‐gel templating method. The 3D network structures of these mesoporous nanotubes (see figure) can provide both electron pathway and lithium ion pathway which benefit their applications in a high rate rechargeable lithium battery

Ultrasensitive electrochemical sensor for p-nitrophenyl organophosphates based on ordered mesoporous carbons at low potential without deoxygenization

<p> p-Nitrophenyl organophosphates (OPs) including paraoxon, parathion and methyl parathion, etc, are highly poisonous OPs, for which sensitive and rapid detection method is most needed. In this work, an ultrasensitive electrochemical sensor for the determination of p-nitrophenyl OPs was developed based on ordered mesoporous carbons (OMCs) modified glassy carbon electrode (GCE) (OMCs/GCE). The electrochemical behavior and reaction mechanism of p-nitrophenyl OPs at OMCs/GCE was elaborated by taking paraoxon as an example. Experimental conditions such as buffer pH, preconcentration potential and time were optimized. By using differential pulse voltammetry, the current response of the sensor at -0.085 V was linear with concentration within 0.01-1.00 mu M and 1.00-20 mu M paraoxon. Similar linear ranges of 0.015-0.5 mu M and 0.5-10 mu M were found for parathion, and 0.01-0.5 mu M and 0.5-10 mu M for methyl parathion. The low limits of detection were evaluated to be 1.9 nM for paraoxon, 3.4 nM for parathion and 2.1 nM for methyl parathion (S/N = 3). Common interfering species had no interference to the detection of p-nitrophenyl OPs. The sensor can be applicable to real samples measurement. Therefore, a simple, sensitive, reproducible and cost-effective electrochemical sensor was proposed for the fast direct determination of trace p-nitrophenyl OPs at low potential without deoxygenization. (C) 2014 Elsevier B. V. All rights reserved.</p

Supercritical fluid processing of mesoporous crystalline TiO2 thin films for highly efficient dye-sensitized solar cells

In this study, a high light-to-electricity conversion efficiency of 5.14% was achieved by applying a TiO2 thin film with a thickness of 1.87 µm as an electrode material under an AM 1.5 solar light (100 mW cm−2). This high efficiency can be attributed to post-treatment by the supercritical fluid process and the addition of nanoparticles to the thin film. Supercritical fluid treatment is shown to significantly enhance the thermal stability of these thin films. Thus, the high porosity of the treated films was maintained even upon calcination at a high temperature. Additionally, the addition of crystalline light scattering nanoparticles in the thin film not only increases the crystallinity of the thin films but also ensures capture of the incident light and increases the efficiency of light harvesting. The thin film with well-preserved mesopores among the nanoparticles can capture the incident light efficiently and further increase efficiency of light harvesting, which leads to the remarkably high light-to-electricity conversion efficiency

Synthesis of Nb 2 O 5 Nanorods by a Soft Chemical Process

Single crystalline Nb 2 O 5 nanorods have been successfully synthesized by a soft chemical process, in which only metal Nb powder and water were used as the starting materials. The synthesized Nb 2 O 5 nanorods are highly crystalline and their growth is along [001] direction. The diameter of the nanorods is found to be ca. 50 nm and their lengths up to several micrometers. Based on the experimental results of XRD, SEM, and TEM measurements, the possible mechanism for the formation of Nb 2 O 5 nanorods was discussed