Article
Chemistry, Physical
Feng Hong, Guanjian Cheng, Weihao Hu, Shengyang Wang, Qike Jiang, Junhong Fu, Botao Qiao, Jiahui Huang
Summary: Gold-based catalysts have shown promise for CO preferential oxidation (CO-PROX) reaction in H-2-rich streams due to their high intrinsic activity for CO elimination even at room temperature. However, the competition of H-2 oxidation and the low stability of gold nanoparticles have limited the CO conversion at elevated temperatures. In this study, a Au-Cu bimetallic catalyst prepared by galvanic replacement method was found to exhibit a wide temperature window for CO total conversion (30-100 degrees C) and excellent catalyst stability without deactivation during a 200-hour test. Detailed characterizations and density functional theory (DFT) calculations revealed that the synergistic effect of Au-Cu and the electron transfer from Au to Cu enhanced the chemisorption of CO and weakened the dissociation of H-2, inhibiting the competition of H-2 oxidation and widening the temperature window for CO total conversion.
Article
Chemistry, Physical
Xudong Du, Yun Lang, Kun Cao, Jiaqiang Yang, Jiaming Cai, Bin Shan, Rong Chen
Summary: This paper designs bifunctional Pt/Ru nanoparticle catalysts via selective atomic layer deposition for PROX in H-2, showcasing optimal activity and selectivity. The enhancement in PROX performance is attributed to the elimination of competitive CO adsorption on Pt, allowing neighboring exposed Ru surfaces to provide highly active sites for O-2 dissociation.
JOURNAL OF CATALYSIS
(2021)
Article
Chemistry, Physical
Chuwei Zhu, Xiang-Kui Gu, Wei-Xue Li
Summary: The bimetallic Cu/Rh catalyst is designed to significantly weaken the CO poisoning effect, improve activity, and favor CO oxidation via the OCOO-mediated associative mechanism with modest barriers, showing high low-temperature CO oxidation activity. The catalyst exhibits good structural stability and lower selectivity for H-2 oxidation, making it promising for the PROX reaction at low temperatures.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Biochemistry & Molecular Biology
Henrik E. Hansen, Daniel O. Fakhri, Frode Seland, Svein Sunde, Odne S. Burheim, Bruno G. Pollet
Summary: In this study, Cu@Pt bimetallic nanocatalysts were successfully synthesized using the sonochemical method, exhibiting significantly higher mass activity in the hydrogen evolution reaction compared to traditional Pt catalysts.
Article
Energy & Fuels
Wanjun Zhao, Hui Dang, Lijun Yue, Yongzhao Wang, Ruifang Wu, Haitao Li, Yongxiang Zhao
Summary: A series of Pd-Cu-xSn/Al2O3 catalysts with low tin content were prepared and used for low-temperature CO preferential oxidation (CO-PROX) in H2-rich stream. The addition of Sn promoted the interaction between Sn species and PdCu/Al2O3, improving the stability of active Cu2Cl(OH)3 species. The doping of Sn also hindered the reduction of active Pd species and facilitated the reoxidation of Cu+ species.
Article
Engineering, Environmental
M. Esperanza Adrover, Tanya Wolff, Gabriela Tonetto, Eduardo Lopez
Summary: The performance and stability of mesostructured Pt catalysts for the preferential oxidation of CO in H-2-rich environments were studied. Pt (1%)/Al-MCM-41 exhibited high activity and stability for CO preferential oxidation at 120 degrees C, even when exposed to steam and CO2.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2022)
Article
Chemistry, Physical
Ya Pan, Liuxin Xu, Li Huang, Wenxue He, Hongmei Li, Siyu Wang, Zhixin Long, Zhihu Sun
Summary: The study employed advanced catalytic analysis techniques to reveal the structural changes of active centers in a bimetallic Pt-Co/Al2O3 catalyst during CO oxidation, identifying the surface CoO species embedded through direct Pt-O-Co interfacial bonds as active sites for O-2 activation, leading to enhanced catalytic activity.
ACS APPLIED ENERGY MATERIALS
(2021)
Article
Chemistry, Physical
Chunlei Wang, Heloise Tissot, Markus Soldemo, Junling Lu, Jonas Weissenrieder
Summary: Inverse oxide/metal model systems were used to study catalytic structure-function relationships at an atomic level. Single-site Fe1Ox was grown on a Pt(111) single crystal surface using atomic layer deposition, showing high flexibility in oxidation states and higher intrinsic activity compared to iron oxide nanoparticles. The redox properties of the catalyst were characterized by AP-XPS and the catalyst exhibited efficient CO oxidation at lower temperatures than traditional iron oxide clusters.
Article
Chemistry, Physical
Christos Papadopoulos, Konstantinos Kappis, Joan Papavasiliou, John Vakros, Aspasia Antonelou, Wojciech Gac, Haibin Li, George Avgouropoulos
Summary: CuCe mixed oxides are commonly used for preferential CO oxidation in the purification of hydrogen-rich gas stream. This study investigated the synthesis of various ceria supports and the preparation of CuCe mixed-oxide catalysts. It found that modifying the hydrothermal parameters can tune the properties of the supports, leading to highly active and selective catalysts. The nature of the reduced copper species and the optimum content in oxygen vacancies play crucial roles in the catalytic performance.
Article
Chemistry, Physical
Yejin Song, Daeho Kim, Seunghwa Hong, Taek-Seung Kim, Ki-Jeong Kim, Jeong Young Park
Summary: The formation and impact of the Pt-CoO interface on Pt-Co bimetallic NPs were investigated, revealing that the interfacial structures play a key role in enhancing catalytic activity.
Article
Chemistry, Physical
Xinglin Hou, Qinyang Zhao, Zichen Liu, Dang-Guo Cheng, Fengqiu Chen, Xiaoli Zhan
Summary: By regulating the stability of ceria crystal planes, the catalytic performance of copper species can be enhanced in CO preferential oxidation (COPROX). The study found that the mass transfer between CuOx clusters and CeO2 weakened, and the sintering of CuOx enhanced as the stability of CeO2 exposed planes increased. The CuO/CeO2-400 catalyst prepared from CeO2-400 with suitable crystal plane stability exhibited the highest amount of Cu+-CO and optimal reactivity in the CO-PROX reaction.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Article
Chemistry, Physical
Mehdi Bejaoui, Abdelhakim Elmhamdi, Laura Pascual, Patricia Perez-Bailac, Kais Nahdi, Arturo Martinez-Arias
Summary: The catalytic performance of CoFe2O4 prepared by sol-gel for preferential CO oxidation in a H-2-rich stream was examined, as well as the promoting effects of incorporation of Ce, Co, Cu, and Zr by impregnation on the process. Surface modifications induced in CoFe2O4 upon introduction of the metals hinder a low temperature CO oxidation process but enhance activity above 125 degrees C, with copper-containing catalyst showing methanation activity due to favored reduced states of cobalt.
Article
Chemistry, Multidisciplinary
Shohreh Kianfar, Ahamd Nozad Golikand, Bahman ZareNezhad
Summary: Nanocatalysts of Pt and Pt-M (M: V, MO and W) supported on rGO were successfully synthesized via irradiation, showing higher electrochemical activities for methanol oxidation. Among the catalysts, Pt-W exhibited the best performance, indicating it as a promising electrocatalyst for direct alcohol fuel cells.
JOURNAL OF NANOSTRUCTURE IN CHEMISTRY
(2021)
Article
Chemistry, Physical
Yang Chen, Jian Lin, Lin Li, Xiaoli Pan, Xiaodong Wang, Tao Zhang
Summary: This study found that Pt nanoparticles supported on an inert substrate can catalyze total CO conversion and CO2 selectivity over a broad temperature range, depending on the local structure of Pt active centers. The ensemble of Pt(OH) and metallic Pt plays a critical role in this process.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2021)
Article
Chemistry, Multidisciplinary
M. Jensen, B. Gonano, W. Kierulf-Vieira, P. J. Kooyman, A. O. Sjastad
Summary: This study presents a novel synthesis strategy for producing true solid solution Pt1-xRhx nanoparticles with suppressed undesired shell formation, as well as modified procedures for creating controlled Rh(core)-Pt(shell) and Pt(core)-Rh(shell) nanoparticles.
Article
Materials Science, Multidisciplinary
S. Kato, N. Nakajima, S. Yasui, S. Yasuhara, D. Fu, J. Adachi, H. Nitani, Y. Takeichi, A. Anspoks
Summary: For the first time, the dielectric response of a BaTiO3 thin film under an AC electric field was investigated using microsecond time-resolved X-ray absorption spectroscopy. The study revealed the correlated contributions of each constituent atom on the electronic states, with Ti 3d hybridizing with O 2p and Ti 4p, and Ba contributing to polarization reversal.
Article
Polymer Science
Yosuke Seto, Misa Nishino, Yuki Okazaki, Katsuyoshi Endo, Kazuya Yamamura, Yuji Ohkubo
Summary: The study focused on characterizing a weak boundary layer (WBL) of polytetrafluoroethylene (PTFE) by observing voids on the surface but not on the bulk side. The thickness of the WBL in PTFE was estimated to be of the order of a single micrometer based on the presence or absence of voids.
Article
Crystallography
Indrajit Saha, Ken Kanazawa, Hiroaki Nitani, Shinji Kuroda
Summary: This study investigates the effect of growth conditions on the structural and magnetic properties of (Zn,Fe)Te thin films. The analysis reveals that films grown under Zn-rich conditions exhibit significant differences in structure and magnetism compared to those grown under Te-rich conditions.
JOURNAL OF CRYSTAL GROWTH
(2022)
Article
Polymer Science
Misa Nishino, Yuki Okazaki, Yosuke Seto, Tsuyoshi Uehara, Katsuyoshi Endo, Kazuya Yamamura, Yuji Ohkubo
Summary: This study investigated the effect of plasma treatment on glass-cloth-containing polytetrafluoroethylene (GC-PTFE). The results showed that the adhesion strength between GC-PTFE and stainless steel increased with longer plasma treatment time and improved surface properties, leading to better adhesion compared to pure PTFE under short plasma treatment times.
Article
Chemistry, Multidisciplinary
Naoto Uegaki, Satoshi Seino, Yuji Takagi, Yuji Ohkubo, Takashi Nakagawa
Summary: Pd nanoparticles were immobilized on an ABS substrate using ionizing radiation. Scanning electron microscopy revealed the presence of Pd nanoparticles on the ABS substrate surface. This method can be applied to various materials, not just plastic plates.
Article
Nanoscience & Nanotechnology
Naoyoshi Murata, Takuya Suzuki, Yunli Lin, Hiroaki Nitani, Yasuhiro Niwa, Takahiro Wada, Motohiro Uo, Kiyotaka Asakura
Summary: A battery-driven micro electromechanical system (MEMS) gas sensor has been developed for household safety when using natural gas. The sensor shows excellent sensitivity to methane and maintains stability under reaction conditions, ensuring a long lifetime.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Physics, Applied
Dai Inoue, Toshiki Komatsu, Hideharu Niwa, Hiroaki Nitani, Hitoshi Abe, Yutaka Moritomo
Summary: This systematic study investigates the local structure of Fe2+ and Fe3+ in 11 solvents using EXAFS and XANES. The results show that both Fe2+ and Fe3+ are coordinated by six oxygen atoms of the ligand molecules, forming a FeL (6)-type complex in all solvents. XANES reveals noncentrosymmetric deformation of the [FeL (6)](3+) complex in several solvents. In protic solvents, the coordination number (n (C)) of the second nearest carbon around Fe3+ significantly depends on the ligand L.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2022)
Article
Physics, Multidisciplinary
Dai Inoue, Toshiki Komatsu, Hideharu Niwa, Toshiaki Ina, Hiroaki Nitani, Hitoshi Abe, Yutaka Moritomo
Summary: In this study, the coordination states of Fe2+ and Fe3+ in organic solvents were investigated using spectroscopic techniques. The results showed that Fe3+ formed [FeCl4](-) complex in all the solutions, while Fe2+ formed different coordination structures in different solvents.
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN
(2022)
Article
Chemistry, Multidisciplinary
Jianjun Li, Wenhan Chen, Haolin Wang, Lili Guo, Nuowei Zhang, Jinbao Zheng, Jile Fu, Hiroaki Nitani, Binghui Chen
Summary: An effective method is proposed for synthesizing a hierarchical Co-doped AlPO4 molecular sieve, CoAIP-CTAB, with both framework and extra framework Co identified by XAFS. The obtained nanocrystals show high catalytic activity and stability in the conversion of n-butenes to isobutene, without the need for gas dilution, due to their hierarchical structure and abundant Co sites in the framework. This novel synthesis strategy may inspire the design of similar zeolite catalysts for selective reactions in the industry.
ADVANCED MATERIALS INTERFACES
(2022)
Article
Chemistry, Multidisciplinary
Satoshi Seino, Yuji Ohkubo, Tomonari Magara, Hiroki Enomoto, Eri Nakajima, Tomoki Nishida, Yasuo Imoto, Takashi Nakagawa
Summary: A new method has been developed to introduce the antimicrobial activity of silver nanoparticles into resin substrates. By irradiating the resin substrate with gamma ray or high energy electron beams, silver nanoparticles were immobilized on the resin surface through chemical reactions induced by ionizing radiation. Various resin materials were found to be applicable for this process, and despite the low amount of silver loading, the obtained samples exhibited high antibacterial and antiviral activities.
Article
Chemistry, Multidisciplinary
Erika Miyake, Misa Nishino, Yosuke Seto, Izuru Komatsu, Katsuyoshi Endo, Kazuya Yamamura, Yuji Ohkubo
Summary: In this study, the adhesion strength between PTFE and silicone gel was improved by modifying PTFE with heat-assisted plasma treatment and treating silicone gel with oleophilic SiO2 powder and plasma jet treatment. The adhesion strength of the PTFE/silicone gel assembly was 1.13 N mm(-1) when treated moderately, but only 0.01 N mm(-1) when untreated and treated excessively. Surface evaluation of the silicone gel showed increased hydrophilic functional groups and cross-linking when treated moderately. Surface degradation was observed when treated excessively, leading to lower adhesion strength. The adhesive-free bonding between PTFE and silicone gel can enable the development of freely attachable and detachable IoT devices.
Article
Chemistry, Multidisciplinary
Naoto Uegaki, Satoshi Seino, Yuji Ohkubo, Takashi Nakagawa
Summary: Pd nanoparticles were immobilized on different polymer substrates using ionizing irradiation-induced chemical reactions. The chemical state of the immobilized nanoparticles depended on the substrate type and affected the adhesion strength of copper plating.
Article
Materials Science, Multidisciplinary
Hiroshi Okuda, Kohei Kintsu, Shu Kurokawa, Masao Tabuchi, Hiroaki Nitani, Hajime Kimizuka, Shin-ichi Inoue, Michiaki Yamasaki, Yoshihito Kawamura
Summary: A coarse-grained picture of segregation layers in MgYZn alloys has been confirmed, where the layers are two-dimensional cluster systems bound in stacking faults. The use of EXAFS, small-angle X-ray scattering, and scanning tunneling microscopy showed that the atomic configurations around Y and Zn atoms in the segregation layers are identical, indicating the presence of L12 clusters. This fingerprint was observed in both bulk LPSO structures and dilute MgYZn alloys.
Article
Chemistry, Multidisciplinary
Misa Nishino, Takumi Kodama, Kazuya Yamamura, Yuji Ohkubo
Summary: In this study, a strong adhesion between polytetrafluoroethylene (PTFE) and copper foil was achieved using heat-assisted plasma (HAP) treatment and thermal compression under reduced pressure. This method is advantageous for maintaining a low interface roughness, making it suitable for manufacturing high-frequency printed wiring boards (PWBs). Evaluation: 9 out of 10.
Article
Chemistry, Multidisciplinary
Yuji Ohkubo, Yuki Okazaki, Misa Nishino, Yosuke Seto, Katsuyoshi Endo, Kazuya Yamamura
Summary: During plasma treatment of polymers, the etching rate can be controlled by varying the base pressure. In this study, polytetrafluoroethylene (PTFE) was subjected to plasma treatments using only He gas at various base pressures. The results showed that controlling the base pressure enables flexible selection of the ratio of functional groups generated on PTFE.
