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Li Y, Yu G, Li J, Bian Z, Han X, Wu B, Wu G, Yang Q, Hong X. Universal Synthesis of Amorphous Metal Oxide Nanomeshes. Small 2024:e2401162. [PMID: 38511537 DOI: 10.1002/smll.202401162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 03/11/2024] [Indexed: 03/22/2024]
Abstract
Constructing the pore structures in amorphous metal oxide nanosheets can enhance their electrocatalytic performance by efficiently increasing specific surface areas and facilitating mass transport in electrocatalysis. However, the accurate synthesis for porous amorphous metal oxide nanosheets remains a challenge. Herein, a facile nitrate-assisted oxidation strategy is reported for synthesizing amorphous mesoporous iridium oxide nanomeshes (a-m IrOx NMs) with a pore size of ∼4 nm. X-ray absorption characterizations indicate that a-m IrOx NMs possess stretched Ir─O bonds and weaker Ir-O interaction compared with commercial IrO2. Combining thermogravimetric-fourier transform infrared spectroscopy with differential scanning calorimetry measurements, it is demonstrated that sodium nitrate, acting as an oxidizing agent, is conducive to the formation of amorphous nanosheets, while the NO2 produced by the in situ decomposition of nitrates facilitates the generation of pores within the nanomeshes. As an anode electrocatalyst in proton exchange membrane water electrolyzer, a-m IrOx NMs exhibit superior performance, maintaining a cell voltage of 1.67 V at 1 A cm-2 for 120 h without obvious decay with a low loading (0.4 mgcatalyst cm-2). Furthermore, the nitrate-assisted method is demonstrated to be a general approach to prepare various amorphous metal oxide nanomeshes, including amorphous RhOx, TiOx, ZrOx, AlOx, and HfOx nanomeshes.
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Affiliation(s)
- Youle Li
- Center of Advanced Nanocatalysis (CAN), Department of Applied Chemistry, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China
- Department of Chemistry, Laboratory of Nanomaterials for Energy Conversion (LNEC), University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China
| | - Ge Yu
- Center of Advanced Nanocatalysis (CAN), Department of Applied Chemistry, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China
| | - Junmin Li
- Center of Advanced Nanocatalysis (CAN), Department of Applied Chemistry, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China
| | - Zenan Bian
- Center of Advanced Nanocatalysis (CAN), Department of Applied Chemistry, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China
| | - Xiao Han
- Center of Advanced Nanocatalysis (CAN), Department of Applied Chemistry, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China
| | - Bei Wu
- Center of Advanced Nanocatalysis (CAN), Department of Applied Chemistry, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China
| | - Geng Wu
- Center of Advanced Nanocatalysis (CAN), Department of Applied Chemistry, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China
| | - Qing Yang
- Department of Chemistry, Laboratory of Nanomaterials for Energy Conversion (LNEC), University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China
| | - Xun Hong
- Center of Advanced Nanocatalysis (CAN), Department of Applied Chemistry, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China
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Banti A, Papazisi KM, Balomenou S, Tsiplakides D. Effect of Calcination Temperature on the Activity of Unsupported IrO 2 Electrocatalysts for the Oxygen Evolution Reaction in Polymer Electrolyte Membrane Water Electrolyzers. Molecules 2023; 28:5827. [PMID: 37570796 PMCID: PMC10421380 DOI: 10.3390/molecules28155827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 07/27/2023] [Accepted: 08/01/2023] [Indexed: 08/13/2023] Open
Abstract
Polymer electrolyte membrane (PEM) water electrolyzers suffer mainly from slow kinetics regarding the oxygen evolution reaction (OER). Noble metal oxides, like IrO2 and RuO2, are generally more active for OER than metal electrodes, exhibiting low anodic overpotentials and high catalytic activity. However, issues like electrocatalyst stability under continuous operation and cost minimization through a reduction in the catalyst loading are of great importance to the research community. In this study, unsupported IrO2 of various particle sizes (different calcination temperatures) were evaluated for the OER and as anode electrodes for PEM water electrolyzers. The electrocatalysts were synthesized by the modified Adams method, and the effect of calcination temperature on the properties of IrO2 electrocatalysts is investigated. Physicochemical characterization was conducted using X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area measurement, high-resolution transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) analyses. For the electrochemical performance of synthesized electrocatalysts in the OER, cyclic voltammetry (CV) and linear sweep voltammetry (LSV) were conducted in a typical three-cell electrode configuration, using glassy carbon as the working electrode, which the synthesized electrocatalysts were cast on in a 0.5 M H2SO4 solution. The materials, as anode PEM water electrolysis electrodes, were further evaluated in a typical electrolytic cell using a Nafion®115 membrane as the electrolyte and Pt/C as the cathode electrocatalyst. The IrO2 electrocatalyst calcined at 400 °C shows high crystallinity with a 1.24 nm particle size, a high specific surface area (185 m2 g-1), and a high activity of 177 mA cm-2 at 1.8 V for PEM water electrolysis.
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Affiliation(s)
- Angeliki Banti
- Physical Chemistry Laboratory, Chemistry Department, Aristotle University of Thessaloniki, 541 24 Thessaloniki, Greece
- Chemical Process and Energy Resources Institute, Centre for Research and Technology Hellas, 570 01 Thessaloniki, Greece; (K.M.P.); (S.B.)
| | - Kalliopi Maria Papazisi
- Chemical Process and Energy Resources Institute, Centre for Research and Technology Hellas, 570 01 Thessaloniki, Greece; (K.M.P.); (S.B.)
| | - Stella Balomenou
- Chemical Process and Energy Resources Institute, Centre for Research and Technology Hellas, 570 01 Thessaloniki, Greece; (K.M.P.); (S.B.)
| | - Dimitrios Tsiplakides
- Physical Chemistry Laboratory, Chemistry Department, Aristotle University of Thessaloniki, 541 24 Thessaloniki, Greece
- Chemical Process and Energy Resources Institute, Centre for Research and Technology Hellas, 570 01 Thessaloniki, Greece; (K.M.P.); (S.B.)
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Lee CY, Li SC, Chen CH, Huang YT, Wang YS. Real-Time Microscopic Monitoring of Flow, Voltage and Current in the Proton Exchange Membrane Water Electrolyzer. Sensors (Basel) 2018; 18:E867. [PMID: 29543734 DOI: 10.3390/s18030867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 03/12/2018] [Accepted: 03/12/2018] [Indexed: 11/29/2022]
Abstract
Looking for alternative energy sources has been an inevitable trend since the oil crisis, and close attentioned has been paid to hydrogen energy. The proton exchange membrane (PEM) water electrolyzer is characterized by high energy efficiency, high yield, simple system and low operating temperature. The electrolyzer generates hydrogen from water free of any carbon sources (provided the electrons come from renewable sources such as solar and wind), so it is very clean and completely satisfies the environmental requirement. However, in long-term operation of the PEM water electrolyzer, the membrane material durability, catalyst corrosion and nonuniformity of local flow, voltage and current in the electrolyzer can influence the overall performance. It is difficult to measure the internal physical parameters of the PEM water electrolyzer, and the physical parameters are interrelated. Therefore, this study uses micro-electro-mechanical systems (MEMS) technology to develop a flexible integrated microsensor; internal multiple physical information is extracted to determine the optimal working parameters for the PEM water electrolyzer. The real operational data of local flow, voltage and current in the PEM water electrolyzer are measured simultaneously by the flexible integrated microsensor, so as to enhance the performance of the PEM water electrolyzer and to prolong the service life.
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