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Liu Y, Lin L, Yu L, Mu R, Fu Q. Spatially Separated Active Sites Enable Selective CO Oxidation Reaction on Oxide Catalyst. J Phys Chem Lett 2023; 14:9780-9786. [PMID: 37882533 DOI: 10.1021/acs.jpclett.3c02247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2023]
Abstract
The search for efficient non-noble-metal catalysts able to perform selective oxidation reactions is of great importance, with relevance to many catalytic processes. However, this is often hampered because the origin of the selectivity remains controversial, particularly for reactions catalyzed by oxides. Here, combining high-pressure surface imaging techniques and theoretical calculations, we identify that spatially separated active sites for O2 activation and H2 adsorption on an ultrathin Mn3O4 surface enable selective oxidation of CO over H2. Theoretical calculations reveal that Mn-O pairs for H2 dissociation are separated from Mn-Mn pairs for the formation of adsorbed O2* so that H2 has to surmount much higher barriers for both H2 dissociation and H diffusion while CO can directly react with O2* following the Eley-Rideal process. Our study sheds light on the atomic-level understanding of the surface structure-dependent selective oxidation reaction on oxide catalysts.
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Affiliation(s)
- Yijing Liu
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Le Lin
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Liang Yu
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Rentao Mu
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Qiang Fu
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
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Abdelgawad A, Salah B, Eid K, Abdullah AM, Al-Hajri RS, Al-Abri M, Hassan MK, Al-Sulaiti LA, Ahmadaliev D, Ozoemena KI. Pt-Based Nanostructures for Electrochemical Oxidation of CO: Unveiling the Effect of Shapes and Electrolytes. Int J Mol Sci 2022; 23:15034. [PMID: 36499359 PMCID: PMC9737813 DOI: 10.3390/ijms232315034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 11/09/2022] [Accepted: 11/10/2022] [Indexed: 12/03/2022] Open
Abstract
Direct alcohol fuel cells are deemed as green and sustainable energy resources; however, CO-poisoning of Pt-based catalysts is a critical barrier to their commercialization. Thus, investigation of the electrochemical CO oxidation activity (COOxid) of Pt-based catalyst over pH ranges as a function of Pt-shape is necessary and is not yet reported. Herein, porous Pt nanodendrites (Pt NDs) were synthesized via the ultrasonic irradiation method, and its CO oxidation performance was benchmarked in different electrolytes relative to 1-D Pt chains nanostructure (Pt NCs) and commercial Pt/C catalyst under the same condition. This is a trial to confirm the effect of the size and shape of Pt as well as the pH of electrolytes on the COOxid. The COOxid activity and durability of Pt NDs are substantially superior to Pt NCs and Pt/C in HClO4, KOH, and NaHCO3 electrolytes, respectively, owing to the porous branched structure with a high surface area, which maximizes Pt utilization. Notably, the COOxid performance of Pt NPs in HClO4 is higher than that in NaHCO3, and KOH under the same reaction conditions. This study may open the way for understanding the COOxid activities of Pt-based catalysts and avoiding CO-poisoning in fuel cells.
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Affiliation(s)
- Ahmed Abdelgawad
- Center for Advanced Materials, Qatar University, Doha 2713, Qatar
- Gas Processing Center, College of Engineering, Qatar University, Doha 2713, Qatar
| | - Belal Salah
- Center for Advanced Materials, Qatar University, Doha 2713, Qatar
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Private Bag 3, P O Wits, Johannesburg 2050, South Africa
| | - Kamel Eid
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Private Bag 3, P O Wits, Johannesburg 2050, South Africa
| | | | - Rashid S. Al-Hajri
- Petroleum and Chemical Engineering Department, Sultan Qaboos University, Muscat 123, Oman
| | - Mohammed Al-Abri
- Nanotechnology Research Centre, Sultan Qaboos University, P.O. Box 17, PC 123, SQU, Al-Khoudh 123, Oman
- Department of Petroleum and Chemical Engineering, College of Engineering, Sultan Qaboos University, P.O. Box 33, PC 123, SQU, A-Khoudh 123, Oman
| | | | - Leena A. Al-Sulaiti
- Department of Mathematics, Statistics, and Physics, Qatar University, Doha 2713, Qatar
| | - Doniyorbek Ahmadaliev
- Andijan State Pedagogical Institute, Andijan 170100, Uzbekistan
- Presidential School in Andijan, Agency for Presidential Educational Institutions of the Republic of Uzbekistan, Andijan 170100, Uzbekistan
| | - Kenneth I. Ozoemena
- Gas Processing Center, College of Engineering, Qatar University, Doha 2713, Qatar
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Sato K, Zaitsu S, Kitayama G, Yagi S, Kayada Y, Nishida Y, Wada Y, Nagaoka K. Operando Spectroscopic Study of the Dynamics of Ru Catalyst during Preferential Oxidation of CO and the Prevention of Ammonia Poisoning by Pt. JACS AU 2022; 2:1627-1637. [PMID: 35911446 PMCID: PMC9326823 DOI: 10.1021/jacsau.2c00195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Hydrogen is a promising clean energy source. In domestic polymer electrolyte fuel cell systems, hydrogen is produced by reforming of natural gas; however, the reformate contains carbon monoxide (CO) as a major impurity. This CO is removed from the reformate by a combination of the water-gas shift reaction and preferential oxidation of CO (PROX). Currently, Ru-based catalysts are the most common type of PROX catalyst; however, their durability against ammonia (NH3) as an impurity produced in situ from trace amounts of nitrogen also contained in the reformate is an important issue. Previously, we found that addition of Pt to an Ru catalyst inhibited deactivation by NH3. Here, we conducted operando XAFS and FT-IR spectroscopic analyses with simultaneous gas analysis to investigate the cause of the deactivation of an Ru-based PROX catalyst (Ru/α-Al2O3) by NH3 and the mechanism of suppression of the deactivation by adding Pt (Pt/Ru/α-Al2O3). We found that nitric oxide (NO) produced by oxidation of NH3 induces oxidation of the Ru nanoparticle surface, which deactivates the catalyst via a three-step process: First, NO directly adsorbs on Ru0 to form NO-Ruδ+, which then induces the formation of O-Ru n+ by oxidation of the surrounding Ru0. Then, O-Ru m+ is formed by oxidation of Ru0 starting from the O-Ru n+ nuclei and spreading across the surface of the nanoparticle. Pt inhibits this process by alloying with Ru and inducing the decomposition of adsorbed NO, which keeps the Ru in a metallic state.
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Affiliation(s)
- Katsutoshi Sato
- Department of Chemical Systems Engineering, Graduate school of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan
- Elements Strategy Initiative for Catalysts and Batteries, Kyoto University, 1-30 Goryo-Ohara, Nishikyo-ku, Kyoto 615-8245, Japan
| | - Shuhei Zaitsu
- Department of Applied Chemistry, Graduate School of Engineering, Oita University, 700 Dannoharu, Oita 870-1192, Japan
| | - Godai Kitayama
- Department of Applied Chemistry, Graduate School of Engineering, Oita University, 700 Dannoharu, Oita 870-1192, Japan
| | - Sho Yagi
- Department of Applied Chemistry, Graduate School of Engineering, Oita University, 700 Dannoharu, Oita 870-1192, Japan
| | - Yuto Kayada
- Department of Applied Chemistry, Graduate School of Engineering, Oita University, 700 Dannoharu, Oita 870-1192, Japan
| | - Yoshihide Nishida
- Department of Chemical Systems Engineering, Graduate school of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan
| | - Yuichiro Wada
- Department of Integrated Science and Technology, Faculty of Science and Technology, Oita University, 700 Dannoharu, Oita 870-1192, Japan
| | - Katsutoshi Nagaoka
- Department of Chemical Systems Engineering, Graduate school of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan
- Elements Strategy Initiative for Catalysts and Batteries, Kyoto University, 1-30 Goryo-Ohara, Nishikyo-ku, Kyoto 615-8245, Japan
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