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Influences of Nanostructures of Sn and Ir for the Oxygen Evolution Reaction in Polymer Electrolyte Membrane Water Electrolysis

Bunea, S. (author), Li, M. (author), Demiröz, E. (author), Zeng, Peng (author), Willinger, Marc Georg (author), Urakawa, A. (author)

The influence of nanostructures and interaction of Sn and Ir in oxygen evolution catalysts in a polymer electrolyte membrane electrolyzer were investigated. For this aim, two synthesis methods, namely, the one-step solution combustion method and the precipitation-deposition method with sodium borohydride reduction, were evaluated to prepare...

journal article 2024

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Liquid-Liquid-Gas Triphasic Hydrogenation of Bicarbonate to Formate in a Continuous Flow Tubular Reactor

Afreen, G. (author), Bansode, Atul (author), Wada, Kazuhito (author), Hirano, Makoto (author), Matsuda, Hirokazu (author), Urakawa, A. (author)

Multiphasic reaction of bicarbonate hydrogenation to form formate using homogeneous Ru PNP pincer catalyst in a continuous flow tubular reactor is reported. The reaction system consists of three phases. Catalyst is dissolved in toluene while potassium bicarbonate is dissolved in water. The significance of efficient mixing among the organic...

journal article 2024

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High-Pressure oxidative coupling of methane on alkali metal catalyst – Microkinetic analysis and operando thermal visualization

Yu, Yuhang (author), Obata, Keisuke (author), Movick, William J. (author), Yoshida, Shintaro (author), Palomo Jiménez, J. (author), Lundin, Sean Thomas B. (author), Urakawa, A. (author), Sarathy, S. Mani (author), Takanabe, Kazuhiro (author)

To introduce promotional H₂O effects for both CH₄ rate and C₂ selectivity, the OH radical formation, catalyzed through H₂O activation with O₂ surface species, was critical for modeling selective Mn-K₂WO₄/SiO₂ catalysts. Based on our reported experimental...

journal article 2024

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Influence of mixing time on a reversal tolerant anode measured ex situ for a PEMFC

Homan, S.J.T. (author), Aylar, K. (author), Jurjevic, A. (author), Scolari, M. (author), Urakawa, A. (author), Taheri, P. (author)

When no hydrogen can reach the Pt catalyst in the anode for the hydrogen oxidation reaction (HOR) of an operating proton exchange membrane fuel cell (PEMFC), the anode potential increases and causes the cell potential to be reversed compared to normal operation conditions. During this reversal, the oxygen evolution reaction (OER) and carbon...

journal article 2024

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Exploiting the continuity equation for mechanistic understanding through spatially resolved SSITKA-DRIFTS: The role of carbonyls in RWGS over Pt/CeO₂

Vico Van Berkel, D. (author), Urakawa, A. (author)

Insight into mechanisms of heterogeneously catalyzed reactions holds importance in the development and optimization of new catalytic materials. Yet, the approaches often used in such investigations heavily rely on assumptions concerning the reactor and kinetics. Herein we report a new kind of kinetic investigation taking CO₂...

journal article 2024

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Spatiotemporal operando UV–vis spectroscopy: Development and mechanistic alternation of CO oxidation on Pt/Al₂O₃ on the reactor scale

van Beek, L.E. (author), Jain, D. (author), Gholkar, P.V. (author), Eldridge, T.J. (author), Nguyen, H.P. (author), Muramoto, Kei (author), Urakawa, A. (author)

Operando methodologies are widely used in heterogenous catalysis to understand unique state of catalyst materials emerging under specific reaction conditions and to establish catalyst structure-activity relationships. Recent studies highlight the importance of combining multiple operando techniques (multimodal approach) to gain complementary...

journal article 2024

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Integrated CO₂ capture and reduction catalysis: Role of γ-Al₂O₃ support, unique state of potassium and synergy with copper

Pinto, D. (author), Minorello, S. (author), Zhou, Zhouping (author), Urakawa, A. (author)

Carbon dioxide capture and reduction (CCR) process emerges as an efficient catalytic strategy for CO₂ capture and conversion to valuable chemicals. K-promoted Cu/Al₂O₃ catalysts exhibited promising CO₂ capture efficiency and highly selective conversion to syngas (CO + H₂). The dynamic...

journal article 2024

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Combining Atomic Layer Deposition with Surface Organometallic Chemistry to Enhance Atomic-Scale Interactions and Improve the Activity and Selectivity of Cu-Zn/SiO₂ Catalysts for the Hydrogenation of CO₂ to Methanol

Zhou, Hui (author), Docherty, Scott R. (author), Phongprueksathat, N. (author), Chen, Zixuan (author), Bukhtiyarov, Andrey V. (author), Prosvirin, Igor P. (author), Safonova, Olga V. (author), Urakawa, A. (author), Copéret, Christophe (author), Müller, Christoph R. (author), Fedorov, Alexey (author)

The direct synthesis of methanol via the hydrogenation of CO₂, if performed efficiently and selectively, is potentially a powerful technology for CO₂ mitigation. Here, we develop an active and selective Cu-Zn/SiO₂ catalyst for the hydrogenation of CO₂ by introducing copper and zinc onto...

journal article 2023

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Light and Mass Transport Computations Guide the Fabrication of 3D-Structured TiO₂and Au/TiO₂Aerogel Photocatalysts for Efficient Hydrogen Production in the Gas Phase

Rebber, Matthias (author), Sannemüller, Hendrik (author), Jaruszewski, Michael (author), Pfannkuche, Daniela (author), Urakawa, A. (author), Koziej, Dorota (author)

Efficient mass transfer and light utilization are essential for high photocatalytic production rates. Here, we present a hierarchical three-dimensional (3D)-printed aerogel photocatalyst that unites both aspects by taking inspiration from the light scattering in clouds during photochemical processes and from mass transfer in plants during...

journal article 2023

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Combined capture and reduction of CO₂ to methanol using a dual-bed packed reactor

Wirner, Luca C. (author), Kosaka, Fumihiko (author), Sasayama, T. (author), Liu, Yanyong (author), Urakawa, A. (author), Kuramoto, Koji (author)

Recently, carbon capture and reduction (CCR) technology has gained interest to directly convert CO₂ to value-added products without requiring purification of CO₂ and its subsequent transportation. CCR to methanol in one dual function material (DFM) poses mechanistic and kinetic challenges. To counteract this, a process...

journal article 2023

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The 12th International Conference on Environmental Catalysis (ICEC2022), Osaka (Japan), July 30th – August 2nd, 2022

Yamashita, Hiromi (author), Bian, Zhenfeng (author), Urakawa, A. (author), Stockenhuber, Michael (author)

contribution to periodical 2023

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Catalytic Oxidative Coupling of Methane: Heterogeneous or Homogeneous Reaction?

Hu, L. (author), Pinto, D. (author), Urakawa, A. (author)

Direct valorization of methane via oxidative coupling of methane (OCM) is an encouraging alternative to conventional oil-based processes for the production of light hydrocarbons (ethane and ethylene). Abundant, inexpensive simple oxides such as MgO and La₂O₃ possess the ability to selectively activate methane. However,...

journal article 2023

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Bifunctionality of Re Supported on TiO₂ in Driving Methanol Formation in Low-Temperature CO₂ Hydrogenation

Phongprueksathat, N. (author), Ting, Kah Wei (author), Mine, Shinya (author), Jing, Yuan (author), Toyoshima, Ryo (author), Kondoh, Hiroshi (author), Shimizu, Ken Ichi (author), Toyao, Takashi (author), Urakawa, A. (author)

Low temperature and high pressure are thermodynamically more favorable conditions to achieve high conversion and high methanol selectivity in CO₂ hydrogenation. However, low-temperature activity is generally very poor due to the sluggish kinetics, and thus, designing highly selective catalysts active below 200 °C is a great...

journal article 2023

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Electrochemical Conversion of NO to NH₃ in a PEM Cell

Bunea, S. (author), Coppens, Manoj (author), Urakawa, A. (author)

The continuous electrochemical NO reduction to ammonia in a PEM cell was investigated in this work. We used a ruthenium-based catalyst at the cathode and an iridium oxide catalyst at the anode. The highest ammonia faradaic efficiency was observed at 1.9 V cell voltage. Adjusting the NO flow allowed to achieve 97% NO conversion and 93% ammonia...

journal article 2023

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Enabling complete conversion of CH₄ and CO₂ in dynamic coke-mediated dry reforming (DC-DRM) on Ni catalysts

Pinto, D. (author), Hu, L. (author), Urakawa, A. (author)

Dynamic coke-mediated dry reforming of methane (DC-DRM) is an unsteady-state strategy to overcome the limitations of co-feed operation, including the fast deactivation of the catalysts and the loss of valuable H₂ in the reverse water gas-shift reaction. This paper proves the feasibility of DC-DRM on Ni-based catalytic systems,...

journal article 2023

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Towards Higher NH₃ Faradaic Efficiency: Selective-Poisoning of HER Active Sites by Co-Feeding CO in NO Electroreduction**

Li, M. (author), Verkuil, Jarco (author), Bunea, S. (author), Kortlever, R. (author), Urakawa, A. (author)

Direct electroreduction of nitric oxide offers a promising avenue to produce valuable chemicals, such as ammonia, which is an essential chemical to produce fertilizers. Direct ammonia synthesis from NO in a polymer electrolyte membrane (PEM) electrolyzer is advantageous for its continuous operation and excellent mass transport characteristics...

journal article 2023

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Oxidative coupling of methane under microwave: core-shell catalysts for selective C₂ production and homogeneous temperature control

Kaneda, R. (author), Palomo Jiménez, J. (author), Hu, L. (author), Urakawa, A. (author)

The oxidative coupling of methane (OCM) was investigated using a catalyst with a core@shell structure or a physical mixture comprised of MgO and SiC or Fe₃O₄, which was thermally activated via two different heating methods, namely, conventional resistive heating and microwave heating. The use of microwave radiation...

journal article 2023

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Insertion of MXene-Based Materials into Cu–Pd 3D Aerogels for Electroreduction of CO₂ to Formate

Abdinejad, M. (author), Subramanian, S.S. (author), Motlagh, Mozhgan Khorasani (author), Ripepi, D. (author), Pinto, D. (author), Li, Mengran (author), Middelkoop, J. (author), Urakawa, A. (author), Burdyny, T.E. (author)

The electrochemical CO₂ reduction reaction (CO₂RR) is an attractive method to produce renewable fuel and chemical feedstock using clean energy sources. Formate production represents one of the most economical target products from CO₂RR but is primarily produced using post-transition metal catalysts that...

journal article 2023

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Dimethyl carbonate synthesis from CO2 and methanol over CeO2: elucidating the surface intermediates and oxygen vacancy-assisted reaction mechanism

Stoian, Dragos (author), Sugiyama, Toshiyuki (author), Bansode, Atul (author), Medina, Francisco (author), van Beek, Wouter (author), Hasegawa, Jun-ya (author), Nakayama, Akira (author), Urakawa, A. (author)

Surface intermediate species and oxygen vacancy-assisted mechanism over CeO2 catalyst in the direct dimethyl carbonate (DMC) synthesis from carbon dioxide and methanol are suggested by means of transient spectroscopic methodologies in conjunction with multivariate spectral analysis. How the two reactants, i.e. CO2 and methanol, interact with the...

journal article 2023

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Oxidation Catalysis of Crystalline Mo₃VO_x for the Selective Oxidation of Ethane

Ishikawa, Satoshi (author), Shimoda, Kosuke (author), Kamachi, Takashi (author), Aoki, Nagisa (author), Hagiwara, Takeshi (author), Urakawa, A. (author), Ueda, Wataru (author)

Oxidative dehydrogenation of ethane (ODHE) is an essential reaction in modern society to produce ethylene. The orthorhombic Mo₃VO_x catalyst (MoVO) was reported as one of the best catalysts for this reaction after a particular redox treatment to generate lattice oxygen defects. This study elucidates the location and...

journal article 2023