Watanabe LaboratoryWatanabe Laboratory
WATANABE LABORATORY / RESEARCH
Four research themes spanning materials, structures, reactors and energy supply. We connect catalysis with reaction engineering to develop molecular transformations into processes.
01 / CARBON CIRCULATION
We combine CO₂ conversion, syngas production and solid-carbon fixation in reaction systems for carbon circulation.
We study reaction processes that use CO₂ and methane as carbon sources to produce syngas for fuels and chemicals, or solid carbon that can be recovered and used. Alongside catalytic molecular transformations, we investigate combinations of reactors and the separation and recovery of products to control where carbon goes.
To convert industrial exhaust gases into resources on site, we study the relationships between gas composition, reaction temperature, flow rate and reaction equilibrium. We connect catalyst performance with the carbon balance of the entire process, aiming for continuous conversion and recovery.
We convert CO₂ into carbon monoxide using the reverse water-gas shift reaction (RWGS) and dry reforming of methane (DRM). For syngas, which consists of hydrogen and carbon monoxide, we investigate how combinations of reaction conditions and catalysts affect its composition and production rate.
We combine RWGS with reactions that produce solid carbon from carbon monoxide, as well as methanation with reforming and decomposition. We investigate where carbon forms, its morphology, its accumulation on catalysts and recovery methods, developing processes that extract carbon while reactions continue.
We connect multiple reaction stages and adjust temperature, gas composition and water removal at each stage. By examining the role of each reaction and material transfer between stages, we assess CO₂ conversion, product recovery and carbon use across the entire reactor system.
02 / STRUCTURED CATALYSTS
We use spiral structures, porous metals and washcoats to build catalytic reactors that account for heat and mass transfer.
In catalytic reactors, reaction performance depends on catalyst activity, gas flow, heat transfer and mass transfer to catalyst surfaces. We use structured catalysts based on spirals and porous metals to create reaction environments through both materials and geometry.
We deposit catalytic components on substrates by washcoating and plating, adjusting the catalyst distribution and flow-channel geometry. We combine reaction experiments with flow and heat-transfer analysis to investigate gas transport to catalysts and the transfer of reaction heat.
We study how spiral twisting and porous-metal flow channels affect gas mixing, residence and contact with catalysts. We examine the relationship between reaction performance and pressure drop as flow increases, seeking reactor geometries suited to the required throughput.
We form catalyst layers on metal substrates using methods including washcoating and electroless plating. We study how catalyst loading, distribution and adhesion relate to reaction performance, making use of substrate heat conduction and catalyst functionality.
We study flow and temperature distributions inside reactors through experiments and computational fluid dynamics (CFD). Using reactions such as CO₂ methanation, we evaluate how structured-catalyst geometry contributes to distributing generated heat and supplying reaction gases.
03 / e-REACTION PROCESS
We introduce electrical energy directly into reactors and catalysts, exploiting rapid response, local heating and compact equipment.
We pass current directly through metal catalyst structures and use the Joule heat generated by electrical resistance for reactions. Generating heat in the catalyst-bearing structure allows us to control the relationship between energy-input locations and reaction locations, and to investigate chemical processes through their heating methods.
We connect the materials and heat-generation properties of electrified catalysts with reactor temperature distributions and heat transfer. We investigate responses to changes in input power, gas flow and reaction composition, developing electrified reaction processes including CO₂ methanation and reforming.
We examine the relationships among current paths, structural electrical resistance, catalyst-layer placement and heat generation. We measure input power and reaction temperature and compare direct heating with external heating to evaluate how the heat-supply method affects catalytic reactions.
We study conversion, product composition and catalyst state in electrified CO₂ methanation (e-Methanation) and dry reforming of methane (e-DRM). For both exothermic and endothermic reactions, we examine the relationship between direct heating and reaction heat.
We combine reactions such as methanation and reforming in stages, adjusting power supply and operating conditions for each stage. We investigate responses to startup and operating changes, control of syngas composition and compact equipment, aiming for reaction systems that can be used on site.
04 / LATTICE SULFUR CATALYSIS
We study redox catalytic processes in which sulfur is released from sulfide lattices and reinserted from H₂S, repeatedly using lattice sulfur through sulfur vacancies.
We use the lattice sulfur (lattice S) that forms sulfides as a chemical species participating in reactions. We focus on its involvement in hydrogen abstraction from hydrocarbons and release as H₂S, followed by sulfur reinsertion into sulfur vacancies.
Through redox cycles that repeatedly consume and regenerate lattice sulfur, we study alkane dehydrogenation and the conversion of sulfur-containing compounds. We investigate relationships between material state during reactions and products to develop catalytic processes that use sulfur species.
We study how lattice sulfur in sulfides participates in hydrocarbon conversion. For reactions such as alkane dehydrogenation to olefins, we examine relationships between catalyst composition, reaction temperature, gas composition and product selectivity.
We focus on sulfur vacancies left after lattice-sulfur release and sulfur reinsertion using H₂S. We evaluate reaction and regeneration conditions, sulfur transport and catalyst performance during repeated operation to find conditions for repeated use of lattice sulfur.
We investigate hydrocarbon conversion mediated by sulfur species and reactions of sulfur-containing compounds. By relating catalyst-surface conditions to heating methods, we examine how operation using direct heating and other methods affects reactivity and products.
FROM CATALYST TO PROCESS
Our approach connects materials chemistry with reaction engineering, structured catalysts and energy supply.
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