Article
Chemistry, Physical
Melina Zysler, Victor Shokhen, Samuel Spencer Hardisty, Anya Muzikansky, David Zitoun
Summary: In this study, ultralow platinum Pt@Ni@Pt core-bishell nanorods were designed, synthesized, and characterized as bifunctional electrocatalysts with high efficiency in ORR and OER. The structural properties of the nanorods were controlled by adjusting the solvent ratio.
ACS APPLIED ENERGY MATERIALS
(2022)
Article
Chemistry, Physical
Jong-Hwan Park, Jae Chul Ro, Su-Jeong Suh
Summary: FeCo nanoparticles with different surface-layer compositions were synthesized using the polyol method. The FeCo nanoparticles consist of an Fe-rich FeCo alloy core and a Co-rich FeCo oxide layer. Fe59Co41 (S4) exhibits the optimal intrinsic catalytic activity for an oxygen evolution reaction.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Physical
Ha-Young Lee, Caleb Gyan-Barimah, Cheol-Hwan Shin, Jong-Sung Yu
Summary: In this study, carbon materials with both graphiticity and porosity were successfully achieved by utilizing porogen templates. Pyrolysis of g-C3N4 with metallic Mg produced highly graphitized N-doped carbon with abundant Mg3N2 sites. The self-generated Mg3N2 acted as a template for a unique honeycomb-like porous structure, making it an effective support material for PtCo alloy nanoparticles in PEMFC operation, resulting in high peak power density.
JOURNAL OF MATERIALS CHEMISTRY A
(2023)
Article
Materials Science, Multidisciplinary
Jadranka Milikic, Srna Stojanovic, Ljiljana Damjanovic-Vasilic, Rastko Vasilic, Biljana Sljukic
Summary: Four cerium-zeolites were tested as economical bifunctional electrocatalysts for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) in an alkaline solution. Characterization of the four samples was carried out using various methods, and all four zeolites exhibited activity for the studied reactions. Ce-13X cal showed the best performance in terms of OER/ORR, with the lowest onset potential, highest current density for OER, and positive onset and half-wave potentials for ORR.
Article
Chemistry, Analytical
Jadranka Milikic, Srna Stojanovic, Ljiljana Damjanovic-Vasilic, Rastko Vasilic, Lazar Rakocevic, Slavica Lazarevic, Biljana Sljukic
Summary: The study found that calcined forms of ZSM-5 and beta zeolites can be used as better electrocatalysts for the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) due to more active sites and decreased charge-transfer resistance.
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Xu Zhao, Xiangyang Li, Lulu An, Kevin Iputera, Jiang Zhu, Pengfei Gao, Ru-Shi Liu, Zhenmeng Peng, Jinlong Yang, Deli Wang
Summary: This study presents a versatile strategy to enhance the anodic hydrogen oxidation reaction (HOR) performance in alkaline electrolytes. By inserting nitrogen into nickel nanosheets and precisely controlling the orbital hybridization and strain fields, optimized adsorption of critical hydrogen intermediates and hydroxyl species is achieved, thereby accelerating the rate of the HOR. This strategy provides a promising approach to design robust and economic catalysts for energy-related electrocatalysis through finely engineering the orbital hybridization and strain fields.
ENERGY & ENVIRONMENTAL SCIENCE
(2022)
Article
Chemistry, Physical
Yu Zhang, Luca Mascaretti, Michele Melchionna, Olivier Henrotte, Stepan Kment, Paolo Fornasiero, Alberto Naldoni
Summary: A fabrication approach was developed to create TiN/F-doped carbon hybrids with high catalytic activity for H2O2 production. These hybrids showed a maximum H2O2 selectivity of 90% and achieved a H2O2 productivity of 207 mmol g(TiN) (-1) h(-1) at 0.2 V vs RHE. The formation of nanocomposites played a key role in achieving high currents, with increased TiO x N y surface content promoting higher H(2)O(2) selectivity and fluorinated nanocarbon imparting good stability to the electrodes due to their superhydrophobic properties.
Article
Chemistry, Physical
Jitong Yan, Yanyan Liu, Runan Wang, Meirong Xia, Jing Wang, Faming Gao, Yongfu Tang
Summary: Bamboo-like carbonitride nanotubes with high-density multi-type active sites are synthesized to omni-directionally utilize carbon-based material in nanoscale and improve its catalytic activity. The CoO@Co-N-bCNT electrocatalyst exhibits high catalytic activity for ORR with high stability, showing great potential for practical applications.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Chemistry, Physical
Mingrui Wei, Hui Kang, Chao Wang, Guanlun Guo, Yihui Liu, Qiang Ma
Summary: In this paper, two bimetallic manganese-cobalt spinel oxide supported on carbon nanotube (MnCo2O4/CNT) composite materials with different crystal planes exposed were synthesized by adjusting the amount of ammonia during the hydrothermal process. It was found that the MnCo2O4/CNT-800 composite material exposed to the (112) crystal plane exhibited higher oxygen reduction reaction (ORR) catalytic activity in alkaline electrolyte. This was attributed to the greater specific surface area, exposure of high-index crystal plane, and high-valence metal sites on the surface. Density functional theory (DFT) calculations confirmed the improved adsorption and ORR thermodynamics on the (112) crystal plane. This work provides a strategy for the development of advanced bimetallic spinel electrocatalysts.
APPLIED SURFACE SCIENCE
(2023)
Article
Chemistry, Multidisciplinary
Tatiana Priamushko, Eko Budiyanto, Nicolas Eshraghi, Claudia Weidenthaler, Juergen Kahr, Marcus Jahn, Harun Tueysuez, Freddy Kleitz
Summary: Ordered mesoporous CuNiCo oxides prepared by nanocasting demonstrate excellent electrocatalytic performance for oxygen reduction and oxygen evolution reactions, with the optimal Cu/Ni ratio being 1:4.
Review
Chemistry, Multidisciplinary
Tianlei Wang, Arunabhiram Chutia, Dan J. L. Brett, Paul R. Shearing, Guanjie He, Guoliang Chai, Ivan P. Parkin
Summary: Palladium-based alloy materials are being considered as potential substitutes for platinum-based catalysts in fuel cells for the reduction of oxygen. Through a scientometric analysis, research fronts and hotspots have been identified, with volcano plots showing general principles for catalyst modifications to enhance the oxygen reduction reaction. Various influencing factors, such as alloying, structure, and particle size, are discussed for their potential in improving the ORR activity.
ENERGY & ENVIRONMENTAL SCIENCE
(2021)
Review
Chemistry, Physical
Ming Zhou, Jiangna Guo, Jiye Fang
Summary: This review article discusses the mechanisms of oxygen reduction reaction (ORR) of palladium (Pd)-based electrocatalysts in alkaline media and various strategies for designing high-performance Pd-based catalysts. It also provides insights into future challenges and research directions in the rational design and controlled synthesis of Pd-based ORR electrocatalysts.
Article
Chemistry, Inorganic & Nuclear
Siyu Dai, Yuqi Liu, Yunjie Mei, Jue Hu, Kaiming Wang, Yanghua Li, Nanhao Jin, Xinying Wang, Huilong Luo, Wei Li
Summary: A novel two-dimensional Co-MOF material with excellent OER and HER catalytic performance was prepared using mixed organic ligands. The integration of Fe dopant and amorphous interface into Co-MOF improves its electrocatalytic performance, showing potential for developing electrocatalysts for water splitting.
DALTON TRANSACTIONS
(2022)
Article
Chemistry, Multidisciplinary
Yanqiang Li, Zehao Yin, Xuan Liu, Ming Cui, Siru Chen, Tingli Ma
Summary: Molybdenum carbide-based catalysts show great potential in electrochemical reactions such as the hydrogen evolution reaction and oxygen evolution reaction due to their unique electronic structure and physicochemical properties. Research has systematically summarized the synthesis strategies, structure, and catalytic performance of these catalysts, highlighting the relationships between process-structure-property and analyzing catalytic mechanisms. Existing challenges and future perspectives for further development of molybdenum carbide-based catalysts have also been discussed.
MATERIALS TODAY CHEMISTRY
(2021)
Review
Chemistry, Physical
Saswati Santra, Verena Streibel, Ian D. Sharp
Summary: The transition from a global economy dependent on fossil fuels to one based on sustainable energy conversion technologies is the primary challenge of the day. Earth-abundant bifunctional transition metal catalysts, especially those based on molybdenum (Mo), show great promise in reducing cost, simplifying systems, and providing prospects for accelerated scaling and sustainable material reuse. This comprehensive review focuses on recent progress in Mo-based multifunctional catalysts, discussing various formations and structures, as well as emerging trends and opportunities in this promising materials space.
Article
Chemistry, Physical
Xiaofei Lu, Tatsuya Shinagawa, Kazuhiro Takanabe
Summary: Apart from the choice of electrocatalyst, the catalytic performance is greatly affected by the reaction conditions (pressure and temperature) and the operating current density. Strategies developed at low current densities may not be applicable for achieving high electrocatalytic performance. This study focuses on the high flux electroreduction of CO over Cu based electrocatalysts in the form of gas-diffusion electrodes. By conducting detailed microkinetic analysis, the study establishes rate expressions based on elementary steps and interprets the reaction pathways.
Article
Chemistry, Physical
Keisuke Obata, Tomohiro Higashi, Feifan Ye, Masao Katayama, Kazuhiro Takanabe
Summary: Semiconductor photocatalysts are promising for solar energy conversion, and SrTaO2N with a band gap of 2.1 eV is a candidate for visible-light-driven water splitting. However, its poor charge separation efficiency due to reduced Ta4+ sites limits its water splitting efficiency. This study focuses on improving the photocatalytic activity of SrTaO2N by introducing foreign metal cations with a low oxidation state. Among the samples investigated, 1.0 mol % Ga3+-doped SrTaO2N significantly improves the photocatalytic activity, possibly by suppressing the formation of Ta4+ species.
Article
Chemistry, Multidisciplinary
Ayato Takabayashi, Fuminao Kishimoto, Hiroto Tsuchiya, Hitoshi Mikami, Kazuhiro Takanabe
Summary: This study investigates the protection of metal nanoparticles from sintering by selectively forming nanoscale SiO2 shells on Pd supported on TiO2 by ultraviolet (UV) light irradiation. The SiO2 shell prevents thermal aggregation of Pd nanoparticles, maintaining the catalyst's activity even at high temperatures.
NANOSCALE ADVANCES
(2023)
Article
Engineering, Chemical
Yuhang Yu, Sean-Thomas B. Lundin, Keisuke Obata, S. Mani Sarathy, Kazuhiro Takanabe
Summary: A comprehensive microkinetic mechanism for the oxidative coupling of methane (OCM) was developed and verified using a La2O3-CeO2 catalyst. The mechanism accurately predicted the temperature and pressure dependencies of the reaction, providing guidance for achieving high C2-3 yields.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2023)
Article
Chemistry, Multidisciplinary
Huihang Qiu, Keisuke Obata, Zhicheng Yuan, Takeshi Nishimoto, Yaerim Lee, Keisuke Nagato, Ikuya Kinefuchi, Junichiro Shiomi, Kazuhiro Takanabe
Summary: The green hydrogen economy is important for carbon neutrality, but industrial-scale water electrolysis needs improvement in efficiency, operation costs, and capital costs. A detailed understanding of bubble behavior in water electrolyzers is necessary to control bubbles. This study investigates how electrolyte properties affect bubble detachment sizes and establishes a quantitative relationship to regulate bubble management through electrolyte engineering.
Article
Chemistry, Multidisciplinary
Hiroki Komiya, Keisuke Obata, Melody Wada, Takeshi Nishimoto, Kazuhiro Takanabe
Summary: Developing highly active electrocatalysts and conductive electrolytescan improve water-splitting efficiency in the presence of chloride ions. This study introduces a new electrolyte engineering approach using a Cl--containing borate/carbonate mixed buffer electrolyte, which enhances conductivity and achieves a competitive value compared to 30 wt % KOH. The optimized performances for HER and OER are achieved by tuning the concentration of cations and operating pH, resulting in a stable zero-gap cell with high faradaic efficiency for seawater splitting.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2023)
Article
Multidisciplinary Sciences
Fuminao Kishimoto, Tatsushi Yoshioka, Ryo Ishibashi, Hiroki Yamada, Koki Muraoka, Hiroki Taniguchi, Toru Wakihara, Kazuhiro Takanabe
Summary: Microwave-driven catalytic systems are being recognized for their role in electrification of the chemical industry and creating a unique catalytic reaction field. This study demonstrated the selective heating of single alkali metal cations in aluminosilicate zeolites under microwave irradiation. The selectively heated Cs+ cations showed selective CH4 combustion performance, with COx production occurring only at the heated Cs+ cations while suppressing side reactions in the low-temperature gas phase.
Article
Engineering, Chemical
William J. Movick, Yuuka Kubo, Fuminao Kishimoto, Kazuhiro Takanabe
Summary: The study investigates the impact of in situ NH3 removal techniques on NH3 synthesis reaction, showing that it can significantly increase the reaction rate under milder conditions, overcoming NH3 inhibition and thermodynamic limitations, and can reactivate promoter species.
ACS ENGINEERING AU
(2023)
Article
Chemistry, Physical
Tomohiro Higashi, Hiroshi Nishiyama, Yuriy Pihosh, Kaisei Wakishima, Yudai Kawase, Yutaka Sasaki, Akira Nagaoka, Kenji Yoshino, Kazuhiro Takanabe, Kazunari Domen
Summary: The self-conductivity of tantalum nitride (Ta3N5) thin film-based semitransparent photoanodes can enhance the current in the photoelectrochemical oxygen evolution reaction (PEC OER) without a conducting substrate. By modifying the surface with NiFeOx-electrocatalyst, an optimized Ta3N5 thin film directly fabricated on a transparent insulating quartz substrate achieved a photocurrent density of about 5.9 ± 0.1 mA cm-2 at 1.23 V vs. the reversible hydrogen electrode under simulated AM 1.5G solar illumination. The relationship between the PEC OER performance of NiFeOx-modified Ta3N5 photoanodes and the electrical properties of Ta3N5 thin films was investigated using Hall effect measurements.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Haruka Komada, Keisuke Obata, Duanxing Li, S. Mani Sarathy, Kazuhiro Takanabe
Summary: In this study, a two-stage reactor was used to investigate the successive reactions of oxidative coupling of methane (OCM) products. Homogeneous and heterogeneous gas phase reactions of OCM products on catalysts and supports were systematically investigated. Dehydrogenation and condensation of OCM products were observed in the gas phase, while steam reforming and water gas shift reactions led to the loss of C-2 yield. A design guideline for OCM reactors was proposed based on the findings.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)
Article
Chemistry, Physical
Xiaofei Lu, Tatsuya Shinagawa, Kazuhiro Takanabe
Summary: In addition to the identity of the electrocatalyst materials, the catalytic performance is influenced by the local steady-state environment perturbed by reaction conditions, pressure, and temperature, as well as the operating current density. Strategies developed at low current densities cannot be directly applied to achieve high electrocatalytic performance. This study analyzed the microkinetics of CO electroreduction over high-surface-area Cu-based electrocatalysts, establishing rate expressions and interpreting reaction pathways using Tafel analysis, kinetic isotope effects, and temperature and pressure dependence measurements. The findings revealed the optimal operating conditions for maximizing the performance of specific products.
Article
Chemistry, Physical
Xiaofei Lu, Busra Dereli, Tatsuya Shinagawa, Mohamed Eddaoudi, Luigi Cavallo, Kazuhiro Takanabe
Summary: The reaction mechanisms of electrocatalytic CO2 reduction into CO over Co or Fe complexes were studied using gas diffusion electrodes. Experimental and theoretical calculations showed that Fe-based molecular catalysts had more positive redox potentials but were less effective in desorbing CO, especially at high overpotentials. In contrast, heterogenized Co-based molecular complexes were found to tolerate high coverage of CO and achieved higher reaction rates.
Article
Materials Science, Multidisciplinary
Taro Saito, Rafia Ahmad, Fuminao Kishimoto, Tomohiro Higashi, Masao Katayama, Luigi Cavallo, Kazuhiro Takanabe
Summary: This study synthesized diverse crystal phases of bismuth oxides induced by the addition of tantalum and investigated their optoelectronic and redox properties using experimental and computational methods. The synthesis conditions, phase transition behavior, and crystal structures were determined and characterized. The study also provided insights into the reducibility and substitutional positions of the atoms in the oxides. These findings are significant for the optoelectronic and thermal catalytic applications of bismuth oxides.
JOURNAL OF MATERIALS CHEMISTRY C
(2022)
Article
Materials Science, Multidisciplinary
HanHsuan Huang, Kesiuke Obata, Fuminao Kishimoto, Kazuhiro Takanabe
Summary: This study numerically investigates the impact of a thin p-type modification layer on the photoelectrochemical performance of an n-type photoanode, and finds that the dopant densities are key parameters to control the depletion depths in the p-type modification layer and n-type photon absorber.
MATERIALS ADVANCES
(2022)
Article
Chemistry, Multidisciplinary
Xingyu Qi, Tatsuya Shinagawa, Xiaofei Lu, Yuhki Yui, Masaya Ibe, Kazuhiro Takanabe
Summary: By externally controlling the electrochemical potential of catalysts, this study successfully reduces high coverage of a substance to improve thermal-catalytic rates, leading to a significant increase in CO2 formation rate.
