研究者詳細 - 則永　行庸

Engineering Bilayer Tandem Catalysts on Si-Based Photocathodes for High-performance CO2 Reduction to Produce Methane 査読有り

Wu, H; Si, SH; Wang, HT; Wang, CL; Dai, RC; Li, JN; Fukaya, S; Pan, ZH; Xiong, YJ; Usami, N; Norinaga, K; Kurokawa, Y; Sirisomboonchai, S; Liu, D; Wang, Q

ADVANCED MATERIALS 38 巻 ( 15 ) 頁： e18249 2026年2月

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

Solar-powered CO<inf>2</inf> reduction through photoelectrochemical (PEC) approaches to produce hydrocarbon fuels, such as methane (CH<inf>4</inf>), is one of the most promising paths for supplying sustainable fuels. However, the limited light absorption capability and sluggish kinetics restrict the photocatalytic rate and selectivity for hydrocarbon production. Here, we introduce tandem catalysts on photocathodes designed to enhance controlled sequential reactions involving intermediates and thus the selectivity of CO<inf>2</inf> reduction. Specifically, when mounted on Cu/Ag-Cu bilayer catalysts, the p-type Si photocathode with a pyramid-structured surface dramatically improves CO<inf>2</inf>-to-CH<inf>4</inf> conversion, achieving a selectivity of 60.2 ± 3.4% and a working current density of −32.9 ± 1.9 mA cm−2 at −1.1 V vs. RHE. As identified by operando Raman and synchrotron-radiation Fourier transform infrared spectroscopy and Density Functional Theory, the bottom layer of the Cu/Ag-Cu catalysts comprises Ag and Cu nanoparticles, which catalyse the initial reduction of CO<inf>2</inf> to form *CO and the creation of *H species dissociated from H<inf>2</inf>O, respectively. The top Cu layer subsequently enables the protonation of *CO to *CHO, ultimately yielding CH<inf>4</inf>. This design of tandem catalysts, coupled with a thorough investigation of the reaction mechanisms, offers a powerful approach toward high-performance and selective pathways for solar-powered CO<inf>2</inf> reduction to targeted products.

DOI： 10.1002/adma.202518249

Facile Synthesis and Insight of Atomically Dispersed Ni Catalyst on N-Doped Carbonized Lignin for Highly Efficient Electrochemical CO2 Reduction to CO (vol 16, e202300530, 2023) 査読有り

PubMed

O-23　非滅菌メタン発酵残渣を用いたバイオエタノール生成査読有り

谷村あゆみ, 角澤教子, 小長谷耕平, 藤乗隆行, 廣部智己, 菊地亮太, 則永行庸

バイオマス科学会議発表論文集 21 巻 ( 0 ) 頁： 49 - 50 2025年11月

Park, GD; Sirisomboonchai, S; Norinaga, K

CHEMSUSCHEM 18 巻 ( 17 ) 2025年9月

Acetylene formation via oxidative coupling of methane over monolithic Pt/ Al2O3 and Pt/ZrO2 catalysts 査読有り Open Access

Schardt, S; Çelik, A; Bastian, S; Sirisomboonchai, S; Nakamura, M; Norinaga, K; Lott, P

APPLICATIONS IN ENERGY AND COMBUSTION SCIENCE 23 巻 2025年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Applications in Energy and Combustion Science

This study investigates the influence of key operational parameters – including space velocity, feed gas dilution with nitrogen, and the carbon-to-oxygen (C:O) ratio – on monolithic Pt/Al₂O₃ and Pt/ZrO₂ catalysts for the oxidative coupling of methane (OCM). Optimal operating conditions were identified that yielded high C₂ selectivities, with a notably large share of acetylene. Under ideal conditions, a Pt/ZrO₂ catalyst achieved a maximum C₂ selectivity of 11.3 %, with 84 % acetylene contribution and approximately 90 % methane conversion. Zirconia was found to be a superior support material compared to alumina in terms of catalyst stability and longevity. A number of characterization techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) were applied and revealed significant morphological and structural changes in both catalyst types, induced by the harsh reaction conditions with temperatures exceeding 1200 °C. These findings contribute to the advancement of more robust catalyst formulations and optimized process conditions for the OCM reaction.

DOI： 10.1016/j.jaecs.2025.100357

Ethanol production from non-sterile methane fermentation residues for waste-to-biofuel conversion 査読有り Open Access

Tanimura, A; Kakuzawa, N; Obase, K; Tojo, T; Hirobe, T; Kikuchi, R; Norinaga, K

BIORESOURCE TECHNOLOGY REPORTS 31 巻 2025年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Bioresource Technology Reports

Effective valorization of food waste is essential for sustainable resource management. Methane fermentation residues, a byproduct of biogas production from food waste, are typically used as liquid fertilizer. However, their full potential as bioresource substrates remains underexplored. This study investigated the feasibility of producing bioethanol from non-sterile methane fermentation residues mixed with beverage waste under realistic, low-input conditions. Four sucrose-fermenting yeast strains were evaluated for ethanol production in a non-sterile medium composed of residue and deteriorated beverage (1:1, v/v). Ethanol was detected only under the non-sterile condition, not in filter-sterilized controls, suggesting that native microbial populations did not inhibit—and may have enhanced—fermentation. Saccharomyces pastorianus NBRC 11024T achieved the highest ethanol yield (27.4 g/L), reaching 89.4 % of the theoretical maximum within 48 h. Fermentation efficiency declined when the residue ratio exceeded 70 %, indicating possible inhibition due to nitrogen or volatile fatty acid accumulation. 16S rRNA amplicon sequencing revealed a marked shift in microbial community structure, with Leuconostoc species dominating at later stages. These findings suggest that methane fermentation residues can be used as functional co-substrates for ethanol production and may actively contribute to favorable fermentation conditions. In addition, commercially available beverages were shown to be a suitable model for waste beverages and provided practical insights into real-world applications. This approach offers a scalable, decentralized strategy for low-cost ethanol production and contributes to the development of circular bioresource systems.

DOI： 10.1016/j.biteb.2025.102285

Numerical investigation of polycyclic aromatic hydrocarbons (PAHs) and soot formation from various coals in a two-stage entrained flow gasifier with detailed chemistry 査読有り

P-4-5　単管式伝熱管を用いたCO2昇華槽内の温度分布の予測査読有り

千賀香菜子, 田代元太郎, 山口博泰, 上原友輔, 町田洋, 則永行庸, 齋藤泰洋

日本エネルギー学会大会講演要旨集 34 巻 ( 0 ) 頁： 224 - 225 2025年7月

液化天然ガスの極低温を利用する大気中二酸化炭素直接回収技術Cryo-DAC®の研究開発査読有り

則永行庸

日本エネルギー学会機関誌えねるみくす 104 巻 ( 4 ) 頁： 381 - 386 2025年7月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人日本エネルギー学会

本稿では，液化天然ガス（LNG）の未利用冷熱を活用して大気中の二酸化炭素（CO2）を直接回収する技術「Cryo-DAC®」の概要と，その開発状況について紹介する。Cryo-DAC®は，LNGの極低温を利用して気体のCO2を固体（ドライアイス）へと相転移させ，この過程で生じる減圧環境を用いてCO2を吸収したアミン系吸収液からCO2を再生する点に特徴がある。これにより従来必要とされていた加熱操作が不要で，エネルギー消費を抑えたCO2回収が可能となるポテンシャルを有する。現在，プロセスのスケールアップに向けて，コンセプト実証を目的としたベンチスケール装置の運転を開始している。

DOI： 10.20550/jieenermix.104.4_381

CiNii Research

Li, TL; Fukumoto, K; Zhang, LJ; Lin, YX; Choi, C; Machida, H; Norinaga, K

JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS 188 巻 2025年6月

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 Analytical and Applied Pyrolysis

The substitution of air with O<inf>2</inf>/CO<inf>2</inf> atmosphere is a promising solution for CO<inf>2</inf> recirculation during coal gasification. However, a comprehensive understanding on the formation mechanism of PAHs and soot under different conditions is necessary to reduce their emissions. This work presents simulation results of a two-stage entrained flow coal gasifier in a 250 MW industrial-scale plant using detailed chemistry. The influences of reductor temperature (1000–1200 ℃) and coal types (bituminous coal, sub-bituminous coal, and lignite) on PAHs and soot formations from the coal volatiles in the reductor were simulated through a detailed chemical kinetic model under air and O<inf>2</inf>/CO<inf>2</inf> atmospheres. Results show that 2- and 3-ring aromatics are main PAHs products. Rising temperature has inhibitory effects on PAHs formation, especially for lignite. The O<inf>2</inf>/CO<inf>2</inf> condition reduces the PAHs yield compared with the air condition. Rate of production analysis reveals that conversion of major PAHs occurs mainly between PAHs and their radicals. Vinyl-naphthyl radical and indenyl radical play an important role in the acenaphthylene conversion. In addition, soot production increases with a higher temperature under both air and O<inf>2</inf>/CO<inf>2</inf> conditions. The O<inf>2</inf>/CO<inf>2</inf> condition effectively suppressed soot production through a weaker HACA surface growth route than the air condition. lignite produces the least soot, and sub-bituminous coal produces the most. This study deeply reveals the formation mechanisms of PAHs and soot in a two-stage entrained flow gasifier through detailed chemical kinetic modeling, giving an insight into the complex PAHs and soot formations to assess the design and the operating condition of gasifier with O<inf>2</inf>/CO<inf>2</inf> injection.

DOI： 10.1016/j.jaap.2025.107027

Coal Gasification in a Two-Stage Entrained Flow Gasifier under O2/CO2 Conditions 査読有り

Li, TL; Choi, C; Fukumoto, K; Machida, H; Norinaga, K

ENERGY & FUELS 39 巻 ( 20 ) 頁： 9345 - 9358 2025年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Energy and Fuels

Coal gasification in industrial gasifiers faces challenges related to tar and soot formation, which affect performance and emissions. This study proposes a new numerical approach for simulating coal gasification in a two-stage entrained flow gasifier under different O<inf>2</inf>/CO<inf>2</inf> ratios-blown conditions. The modeling framework incorporates a static simulation for the combustor and couples a multistep coal devolatilization model with an expanded gas-phase reaction model in the reductor. Model validation against experimental data showed prediction accuracies ranging from 4 to 20% for the devolatilization model and from 3 to 25% for the gas-phase reaction model across various species. The validated framework was employed to investigate the effect of varying O<inf>2</inf>/CO<inf>2</inf> ratios in gasifying agents on the gasification performance. Results showed that increasing the O<inf>2</inf>/CO<inf>2</inf> ratio from 30% to 50% increased H<inf>2</inf> production from 3.69% to 13.03% and CO from 34.40% to 55.04% while reducing CO<inf>2</inf> from 48.27% to 19.96%. Higher O<inf>2</inf>/CO<inf>2</inf> ratios inhibited soot formation but increased the tar yield, although the final tar concentration remained well below 1 mg/Nm3. This study highlights the potential of using oxy-fuel gasification with CO<inf>2</inf> recirculation for optimizing syngas quality and advancing CO<inf>2</inf> capture, offering valuable insights for industrial gasifier design and operation within oxy-fuel IGCC systems.

DOI： 10.1021/acs.energyfuels.5c00098

Mechanism investigation of direct electrochemical reduction of CO2-loaded 2-(ethylamino)ethanol solution into CO 査読有り

Dai, RC; Zhang, LJ; Tran, KVB; Sirisomboonchai, S; Machida, H; Norinaga, K

SEPARATION AND PURIFICATION TECHNOLOGY 355 巻 2025年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Separation and Purification Technology

Carbon capture and utilization (CCU) has attracted considerable interest recently as CO<inf>2</inf> emission and global warming have greatly affected various aspects of the environment, economy, and society. However, energy consumption during CCU must be substantially reduced. In this study, we propose an alternative approach using electrochemical reduction to directly convert CO<inf>2</inf>-loaded amine solutions into CO. The effects of the electrodes, temperature, potential, and CO<inf>2</inf> loading on the Faradaic efficiency (FE) of CO were comprehensively investigated. The Ag NPs/CP electrode showed good catalytic performance on the electrochemical reduction of CO<inf>2</inf>-loaded amine solution to CO. By comparing the chemical composition in the solution before and after the electrochemical reaction, we determined that the main source of CO might be free CO<inf>2</inf>, which is mainly converted from bicarbonate rather than carbamate. In addition, electrochemical impedance spectroscopy was used to investigate the resistance during the reaction. The electric double-layer was found over the electrode surface when different amine solutions were used as the electrolyte. The spatial structure of ammonium cations and carbamate plays a key role in the FE of CO in this process.

DOI： 10.1016/j.seppur.2024.129575

Design of an efficient CO2 methanation process and techno-economic analysis with CO2 capture from the flue gas of automotive shredder residue 査読有り Open Access

Wasnik, CG; Nakamura, M; Machida, H; Ito, J; Shiratori, K; Norinaga, K

CHEMICAL ENGINEERING JOURNAL 507 巻 2025年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Chemical Engineering Journal

Recycling and utilizing automotive shredder residue (ASR) is necessary for realizing a sustainable automotive industry. This study conducted a feasibility analysis using a process simulator for Case I, where fuel gas is produced through the gasification of ASR followed by combined heat and power generation using a gas engine, CO<inf>2</inf> capture from exhaust gas through chemical absorption, and production of synthetic methane (CH<inf>4</inf>) using the captured CO<inf>2</inf> and renewable hydrogen produced via water electrolysis powered by renewable energy sources. This process produces not only CH<inf>4</inf> but also surplus electricity, which can be used to produce H<inf>2</inf> or power adjacent equipment. Case II, where fuel gas obtained from ASR gasification was directly methanated, was considered for comparison. This study compared the economic potential of both processes for kiln-type ASR gasification that can process 1,200 kg-ASR/h to produce 3,350 Nm3/h of fuel gas. Case I produced 4,800 tons/year of CH<inf>4</inf> with an energy efficiency of 46.5 %, whereas Case II produced 2,720 tons/year. The levelized production cost of methane in 2050 can be estimated at $1,241/ton and $1,568/ton for Cases I and II, respectively, which are lower than the expected cost of natural gas in market environments by 2050. This study highlights the potential of ASR-derived CO<inf>2</inf> methanation as a carbon–neutral technology that can effectively achieve carbon conversion while producing high-value synthetic methane.

DOI： 10.1016/j.cej.2025.160737

CO2 methanation over low-loaded Ni-M, Ru-M (M = Co, Mn) catalysts supported on CeO2 and SiC 査読有り Open Access

Wasnik, CG; Nakamura, M; Shimada, T; Machida, H; Norinaga, K

CARBON RESOURCES CONVERSION 8 巻 ( 1 ) 2025年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Carbon Resources Conversion

The concentration of the major greenhouse gas CO<inf>2</inf> is rapidly increasing in the atmosphere, leading to global warming and a range of environmental issues. An efficient circulation and utilization of CO<inf>2</inf> is critical in the current environmental context. Methanation, an exothermic process, emerges as a critical strategy for effective CO<inf>2</inf> utilization. On this front, there is a significant demand for rational design of catalysts that maintain high activity and methane selectivity over a wide temperature range (250–550 °C). The catalyst that can promise a consistent reaction even at 500 °C under an atmospheric pressure is thus obliged. The present study investigated bimetallic catalysts with SiC, which is known for its exceptional thermal conductivity, and CeO<inf>2</inf>, which is characterized by its CO₂ affinity, as base materials. We incorporated Ni-M and Ru-M (M = Co and Mn) as the active metals, each loaded at 2 %. Impressively, with merely 20 mg, the Ni-Co/SiC catalyst achieved a CO<inf>2</inf> conversion rate of 77 % and CH₄ selectivity of 88 % at 500 °C, in a fixed-bed tubular reactor system with conditions of H<inf>2</inf>/CO<inf>2</inf> = 4, a total flow rate of 70 ml min−1, and a steady GHSV of 12,000 h−1. Moreover, 2Ni-2Co/CeO<inf>2</inf> catalyst demonstrated exceptional performance with a 76 % conversion of CO<inf>2</inf> and a 83 % selectivity for CH<inf>4</inf>, all under identical conditions. The catalyst's durability was confirmed by a subsequent 40-hour stability test, which showed only a 3–5 % degradation. The developed catalysts were comprehensively characterized by BET/BJH, CO pulse chemisorption, H<inf>2</inf>-TPR, HAADF-STEM-EDS, SEM-EDS and XRD etc. to unveil their physicochemical and surface traits. It was found that Co and Mn, when integrated, effectively restrained the agglomeration of Ni and Ru particles, ensuring optimal metal dispersion on the support. In conclusion, our synthesized bimetallic catalysts shown a sustained catalytic capability, even in the high-temperature environment.

DOI： 10.1016/j.crcon.2024.100241

A New Method to Observe the Internal Amine Distribution in an Amine-Functionalized Resin Sorbent Particle 査読有り

Xu, CH; Liu, PB; Peng, YL; Dou, MY; Jiang, QQ; Jia, XH; Zhang, YM; Norinaga, K

INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH 64 巻 ( 10 ) 頁： 5596 - 5601 2025年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Industrial and Engineering Chemistry Research

Understanding the amine distribution within solid amine sorbents is crucial for enhancing their amine utilization and ultimately improving the CO<inf>2</inf> adsorption capacity. However, suitable characterization methods are lacking. To address this, a novel method was proposed to visualize the distributions of total and accessible amine content within the sorbent particles. In this method, SO<inf>2</inf> was selected to label the accessible amine, while scanning electron microscopy and energy dispersive spectroscopy (SEM/EDS) were used to measure the nitrogen and sulfur content, which were further used to calculate the total amine and accessible amine content, respectively. By this method, the total amine content is found to be evenly distributed, which is also higher than the accessible amine content due to the utilization of nitrogen for cross-linking and the diffusion resistance within the particles. For particle sizes larger than a critical size, accessible amine content is higher near the wall and lower at the core. This gradient becomes less pronounced as particle size decreases and becomes uniform when particle size is below this critical size. Therefore, reducing the particle size of solid amine sorbents to below the critical size range (e.g., 250-338 μm in this study) can effectively enhance CO<inf>2</inf> adsorption capacity by maximuming the accessible amine cont within the sorbent particles.

DOI： 10.1021/acs.iecr.4c05007

Observation and kinetic modeling of carbon dioxide deposition under reduced pressures at cryogenic temperatures 査読有り Open Access

Xiao, SW; Hirayama, M; Machida, H; Norinaga, K

CHEMICAL ENGINEERING SCIENCE 305 巻 2025年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Chemical Engineering Science

Liquefied natural gas (LNG) is typically vaporized through heat exchange with seawater or other sources and used as city gas or power generation fuel, but its cold energy remains underutilized. This study proposes a new CO<inf>2</inf> capture process leveraging LNG's cryogenic temperatures to create a vacuum environment, recovering CO<inf>2</inf> from amine-based solutions as dry ice. CO<inf>2</inf> deposition under cryogenic and vacuum conditions was observed, and a deposition rate model was developed. In the experiment, liquid nitrogen circulated through the tube side of a glass vertical single-tube shell-and-tube heat exchanger (230 mm long), while CO<inf>2</inf> was supplied to the shell side. CO<inf>2</inf> was deposited on the outer surface of a 5-mm diameter tube, with its growth rate measured by a laser displacement sensor. At 293 K and pressures of 140–1000 Pa, experimental results matched a rate model based on energy balance and mass transfer.

DOI： 10.1016/j.ces.2024.121177

Nickel/Zirconia-Catalyzed CO2 Methanation in Differential and Integral Fixed-Bed Reactors: Experimental and Computational Fluid Dynamics Studies 査読有り

Shimada, T; Nakamura, M; Fukumoto, K; Ibrahim, M; Wasnik, CG; Machida, H; Norinaga, K

INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH 64 巻 ( 3 ) 頁： 1473 - 1487 2025年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Industrial and Engineering Chemistry Research

Isothermal conditions and a chemical-kinetics-limited rate should be maintained when measuring the reaction rates of gases on solid catalysts. However, in highly exothermic reactions─such as the Sabatier reaction─temperature variations within the catalyst bed make it challenging to achieve isothermality. In this study, temperature changes in a Ni/ZrO<inf>2</inf> catalyst bed were minimized using α-Al<inf>2</inf>O<inf>3</inf> diluent and high gas hourly space velocities (GHSVs) to achieve low feed gas conversion (differential conditions: 0.9 MPa; 523-873 K; GHSV = 7600-30,000 L/h/g cat). The temperature profile within the catalyst bed was obtained by coupling a previously reported kinetic model with three-dimensional computational fluid dynamics (CFD) simulations. Experiments were also conducted under integral conditions at low GHSVs, resulting in high conversion rates and heat release. CFD simulations accurately reproduced the experimental feed gas conversion and temperature, suggesting that the CFD-simulation-guided kinetic parameters appropriately predicted the methanation characteristics at practically relevant high conversion rates.

DOI： 10.1021/acs.iecr.4c03789

CFD simulation of crude oil fouling from laboratory- to industrial-scale heat exchangers using a weak coupling approach 査読有り

Fukumoto, K; Zhang, W; Choi, C; Tang, F; Machida, H; Norinaga, K

APPLIED THERMAL ENGINEERING 258 巻 2025年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Applied Thermal Engineering

Crude oil fouling is described as an accumulation of unwanted materials such as asphaltene and metallic salt on a heat transfer surface in a pre-heat train of the crude distillation unit in oil refineries, causing an economic loss of 1–1.2 billion U.S. dollars per year in 2019. Computational fluid dynamics is one of the useful simulation tools for numerical research on this topic. However, crude oil fouling is a long-term phenomenon; therefore, the time scale is longer than general computational fluid dynamics problems. The fouling layer in oil refineries grows over several months to several years despite the small pipe diameter of several or several tens of millimetres. For this reason, it is not easy to satisfy the Courant–Friedrichs–Lewy condition. To overcome this problem, we developed a new algorithm based on a weak coupling approach, validated this scheme, and exhibited the application of this technology. In the new algorithm, momentum and pressure fields and enthalpy and mass fraction fields are solved separately. The algorithm was implemented as FoulingFOAM, a crude oil fouling simulator based on OpenFOAM v2006. Then, the solver was first validated with the lab-scale measurements, showing good agreement with the experimental data. Next, industrial-scale data in the two refineries were simulated for validation. It was possible to predict the peak fouling resistance against time. Finally, for both lab- and industrial-scale simulations, the predictions of our numerical tool showed that fouling resistance increased with higher wall temperature, lower crude oil velocity, and higher concentration of fouling species, which were identical to previous measurements. Hence, we concluded that the weak coupling approach is promising for investigating crude oil fouling problems.

DOI： 10.1016/j.applthermaleng.2024.124614