Tokyo Institute of Technology · Materials Science
Professor Tsuyoshi Nagasawa's research lab specializes in advanced energy conversion and environmental materials, focusing on improving the efficiency and durability of clean energy technologies. Key research directions include developing innovative combustion strategies for internal combustion engines—such as thermal stratification via in-cylinder water injection—to enhance fuel efficiency under lean-burn conditions. The lab also investigates nanostructured catalysts, particularly Pt/CeO₂ systems synthesized via flame-assisted methods, for high-temperature applications in fuel cells and emission control. Additionally, the lab contributes to coastal environmental science by analyzing extreme natural disasters, such as the 2011 Tohoku tsunami, to understand structural and geomorphological impacts.
Figures are computed from collected data and may differ slightly.
In order to improve thermal efficiency of spark ignition engine under super-lean burn conditions (excess air ratio <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:mi>λ</mml:mi> <mml:mo>≈</mml:mo> <mml:mn>2</mml:mn> <mml:mo>.</mml:mo> <mml:mn>0</mml:mn> </mml:mrow> </mml:math> ), thermal stratification technique by in-cylinder water injection toward piston surface (stratified water insulated combustion architecture), in which low temper
Flame synthesis of nanoparticles has received much attention due to its scalable production ability and potential for controlling nanoparticle structure by adjusting synthesis parameters. In this study, Pt/CeO2 nanoparticles are synthesized by flame-assisted spray pyrolysis (FASP) using a CH4-N2/O2-N2 burner diffusion flame supplied with atomized precursor droplets toward application as a supported metal catalyst with high thermal stability. The effect of precursor concentration and flame temper
Huge damage of the civil structures caused by Tohoku-Pacific Ocean Earthquake and Tsunami in 2011 has never been seen before in our latest history in terms of that the tsunami has done tremendous damage to the large area. The strong wave power and flow generated by the run-up of it has destroyed many sea and river embankments and buildings in coastal area. Additionally, they caused a large-scale geographical variation. This paper shows one's consideration of the structural damages with massive g
Distribution of electrochemical reaction sites in a composite cathode of solid oxide fuel cell is investigated through active sites imaging by oxygen isotope labeling combined with three-dimensional microstructure observation by focused ion beam–scanning electron microscopy (FIB-SEM). Power generation with oxygen isotope and subsequent cell quenching is conducted at 973 K for LSM/YSZ cathode using a button cell. Through FIB-SEM observation and secondary ion mass spectroscopy (SIMS) analysis, the
Cua Dai beach, located in Hoi An town – Quang Nam province, has experienced serious erosion for the past few years with extremely high speed of shoreline retreat. Despite coastal erosion itself may not be that much problematic, it turns out to be serious problem since there is a large residential area right behind and a huge investment in tourism has been done. Generally, causes of erosion are among unbalance of sediment transport, storm surges and sea level rise. However, the rate of shoreline
In order to improve the performance and stability of anodes for solid oxide fuel cells (SOFCs) under low hydrogen concentration conditions, SrZr0.95Y0.05O3-α (SZY) proton conductor particles were incorporated into the conventional Ni/YSZ anode. Power generation experiments were conducted using the electrolyte-supported single cells with conventional Ni/YSZ and Ni/YSZ-5%SZY anodes. Enhanced output power density under low hydrogen partial pressure conditions was achieved with the modified anode. T
In order to overcome the severe degradation of widely-used Ni-based cathodes in solid oxide electrolysis cells (SOECs), Ni-free oxide cathodes have recently attracted much attention. In this study, CO2 electrolysis mechanism at LSCM ((La0.75Sr0.25)0.97Cr0.5Mn0.5O3) and LSCM/GDC (Gd-doped CeO2) porous cathodes of SOEC, which are promising oxide cathodes, is investigated through active sites imaging by oxygen isotope labeling combined with electrochemical measurements. CO2 electrolysis supplied wi
• Pt/CeO 2 catalysts are synthesized by flame-assisted spray pyrolysis (FASP). • Pt/CeO 2 has bimodal structure with 100 nm-scale particles and single nanoparticles. • Particle formation routes are discussed by droplet evaporation simulation in flame. • Higher flame temperature results in higher Pt dispersion and CO oxidation activity. • FASP-made Pt/CeO 2 shows better thermal stability than impregnation method-made one. Flame synthesis offers the potential for the synthesis of structure-control
Active sites for oxygen reduction reaction in strontium-doped lanthanum manganite (LSM)/scandia-stabilized zirconia (ScSZ) composite cathode of solid oxide fuel cell (SOFC) was visualized in particle scale by oxygen isotope labeling. In order to quench a reaction, a SOFC power generation equipment with a nozzle for direct helium impinging jet to the cell was prepared. A typical electrolyte-supported cell was operated by supplying 18O2 at 1073 K and abruptly quenched to room temperature. During t
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