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Charpentier L, Miranda P, Tallaron H, Nogales FM, Sández-Gómez Á, Bêche E, Balat-Pichelin M. The Oxidation of ZrB 2/MoSi 2 Ceramics in Dissociated Air: The Influence of the Elaboration Technique. MATERIALS (BASEL, SWITZERLAND) 2024; 17:3818. [PMID: 39124482 PMCID: PMC11313290 DOI: 10.3390/ma17153818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2024] [Revised: 06/19/2024] [Accepted: 06/21/2024] [Indexed: 08/12/2024]
Abstract
In order to investigate the most extreme conditions in which materials potentially applicable in reusable thermal shields can be operated, ultra-high-temperature ZrB2 ceramics with 20 vol.% MoSi2 were prepared using two different techniques, cold isostatic pressing (CIP) and robocasting (RC, an additive manufacturing technique), followed by consolidation using pressureless spark plasma sintering (SPS). The oxidation behavior of the resulting materials was analyzed in low-pressure dissociated air at three different temperatures, namely 1800, 2000 and 2200 K. Using XRD and surface and cross-section SEM (coupled with EDS), zirconia was found to form at all three temperatures, while silica was only present at 1800 K, with gaseous SiO forming at a higher temperature. The elaboration technique influences the density of the ceramic, and less dense materials undergo deeper oxidation. This investigation suggests that 2000 K is already beyond the maximum temperature threshold at which damage to ceramics is limited by the formation of protective silica. This study confirms that the selected material is a promising candidate for thermal protection applications.
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Affiliation(s)
- Ludovic Charpentier
- PROMES-CNRS, 7, Rue Du Four Solaire, 66120 Font-Romeu Odeillo, France; (H.T.); (E.B.); (M.B.-P.)
| | - Pedro Miranda
- Department of Mechanical, Energy and Materials Engineering, Industrial Engineering School, University of Extremadura, Avda. de Elvas s/n, 06006 Badajoz, Spain; (P.M.); (F.M.N.); (Á.S.-G.)
| | - Hugo Tallaron
- PROMES-CNRS, 7, Rue Du Four Solaire, 66120 Font-Romeu Odeillo, France; (H.T.); (E.B.); (M.B.-P.)
| | - Florencia M. Nogales
- Department of Mechanical, Energy and Materials Engineering, Industrial Engineering School, University of Extremadura, Avda. de Elvas s/n, 06006 Badajoz, Spain; (P.M.); (F.M.N.); (Á.S.-G.)
| | - Álvaro Sández-Gómez
- Department of Mechanical, Energy and Materials Engineering, Industrial Engineering School, University of Extremadura, Avda. de Elvas s/n, 06006 Badajoz, Spain; (P.M.); (F.M.N.); (Á.S.-G.)
| | - Eric Bêche
- PROMES-CNRS, 7, Rue Du Four Solaire, 66120 Font-Romeu Odeillo, France; (H.T.); (E.B.); (M.B.-P.)
| | - Marianne Balat-Pichelin
- PROMES-CNRS, 7, Rue Du Four Solaire, 66120 Font-Romeu Odeillo, France; (H.T.); (E.B.); (M.B.-P.)
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Li Q, Si W, Peng Y, Wang Y, Li J. Tuning Pd species via electronic metal-support interaction for methane combustion. J Colloid Interface Sci 2024; 667:12-21. [PMID: 38615619 DOI: 10.1016/j.jcis.2024.03.152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 03/19/2024] [Accepted: 03/22/2024] [Indexed: 04/16/2024]
Abstract
Utilizing catalytic combustion to convert methane (CH4) into CO2 and H2O stands as one of the most effective approaches for mitigating unburnt CH4 emissions from natural gas engines. Supported Pd catalysts have been extensively researched for their role in low-temperature CH4 combustion, with their catalytic activity greatly influenced by metal-support interactions. Surface interaction Pd phases, as a special type of Pd species originating from metal-support interactions on supported Pd catalysts, show controversial catalytic performance in CH4 combustion. Moreover, the impact of electronic metal-support interactions (EMSI, which refers to metal-support interactions associated with electron transfer) remains unclear. Hence, we opted for Ce-Zr solid solutions with different Ce:Zr molar ratios as supports and synthesized a range of supported Pd catalysts with varying EMSI intensities. Characterization revealed that as the oxygen vacancy concentration on the support increased, electron transfer weakened, leading to a higher Pd-O-Ce content, resulting in a lower CH4 activation barrier and better catalytic performance. This study offers a promising approach for regulating EMSI and active Pd species on supported catalysts in practical applications.
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Affiliation(s)
- Qi Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Wenzhe Si
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China.
| | - Yue Peng
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Yu Wang
- School of Environmental Science and Engineering, Yancheng Institute of Technology, Yancheng 224051, China
| | - Junhua Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China.
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3
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Yaldagard M, Arkas M. Enhanced Mass Activity and Durability of Bimetallic Pt-Pd Nanoparticles on Sulfated-Zirconia-Doped Graphene Nanoplates for Oxygen Reduction Reaction in Proton Exchange Membrane Fuel Cell Applications. Molecules 2024; 29:2129. [PMID: 38731620 PMCID: PMC11085642 DOI: 10.3390/molecules29092129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 03/07/2024] [Accepted: 04/30/2024] [Indexed: 05/13/2024] Open
Abstract
Developing highly active and durable Pt-based electrocatalysts is crucial for polymer electrolyte membrane fuel cells. This study focuses on the performance of oxygen reduction reaction (ORR) electrocatalysts composed of Pt-Pd alloy nanoparticles on graphene nanoplates (GNPs) anchored with sulfated zirconia nanoparticles. The results of field emission scanning electron microscopy and transmission electron microscopy showed that Pt-Pd and S-ZrO2 are well dispersed on the surface of the GNPs. X-ray diffraction revealed that the S-ZrO2 and Pt-Pd alloy coexist in the Pt-Pd/S-ZrO2-GNP nanocomposites without affecting the crystalline lattice of Pt and the graphitic structure of the GNPs. To evaluate the electrochemical activity and reaction kinetics for ORR, we performed cyclic voltammetry, rotating disc electrode, and EIS experiments in acidic solutions at room temperature. The findings showed that Pt-Pd/S-ZrO2-GNPs exhibited a better ORR performance than the Pt-Pd catalyst on the unsulfated ZrO2-GNP support and with Pt on S-ZrO2-GNPs and commercial Pt/C.
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Affiliation(s)
- Maryam Yaldagard
- Department of Chemical Engineering, Faculty of Engineering, Urmia University, Urmia 5766-151818, Iran
| | - Michael Arkas
- National Centre for Scientific Research “Demokritos”, Institute of Nanoscience and Nanotechnology, 15310 Athens, Greece
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Wang N, Zhou X, Yu X, Song Y, Ullah S, Nie X, Wang N, Zhang L. Preparation of Solid Superacid SO 42-/ZrO 2 and SO 42-/ZrO 2-M xO y (M=Ce, Co, Mn, and Zn) and Its Application in Toluene Nitration. ACS OMEGA 2024; 9:12037-12045. [PMID: 38496941 PMCID: PMC10938450 DOI: 10.1021/acsomega.3c09663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 02/05/2024] [Accepted: 02/09/2024] [Indexed: 03/19/2024]
Abstract
The nitration reaction of aromatic compounds is one of the extensively studied chemical reactions that result in the manufacturing of various industrial products applied in pharmaceuticals, dyes, perfumes, and explosives. A series of modified sulfated zirconia (SZ) catalysts SO42-/ZrO2-MxOy (M=Ce, Co, Mn, Zn, and M/SZ) doped with different metal elements by a coprecipitation method were investigated in the toluene nitration reaction. Various characterization techniques (X-ray diffraction, Brunauer-Emmett-Teller, thermogravimetric analysis, X-ray photoelectron spectroscopy, and temperature-programmed desorption of ammonia) indicated that doping metal elements in SZ led to excellent catalytic properties, increasing the specific surface area of the catalyst and facilitating the formation of a stable tetragonal zirconia phase. Doping zinc and cobalt in SZ enhanced the acidity of the catalyst and formed stronger acidic sites, promoting the generation of nitronium ions and providing more active sites for the toluene nitration reaction. Additionally, it reduced the loss of sulfate ions in the catalytic system that helped in improving the stability of the catalyst. Under the same conditions, the catalytic activity of toluene nitration reaction demonstrated the following order: Zn/SZ > Ce/SZ > Co/SZ > Mn/SZ > SZ, with the zinc-doped SZ catalyst exhibiting the best catalytic performance, achieving a toluene conversion rate of 78.58% and a para/ortho nitrotoluene ratio of 0.67.
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Affiliation(s)
- Ning Wang
- School
of Chemical Engineering, East China University
of Science and Technology, Shanghai 200231, China
| | - Xiaolong Zhou
- East
China University of Science and Technology, Shanghai 200231, China
| | - Xiaoyan Yu
- School
of Chemical Engineering, East China University
of Science and Technology, Shanghai 200231, China
| | - Yueqin Song
- East
China University of Science and Technology, Shanghai 200231, China
| | - Saif Ullah
- School
of Chemical Engineering, East China University
of Science and Technology, Shanghai 200231, China
| | - Xinyao Nie
- Qingyang
Chemical Industry Corporation, Liaoyang 111000, China
| | - Ning Wang
- Qingyang
Chemical Industry Corporation, Liaoyang 111000, China
| | - Lu Zhang
- Qingyang
Chemical Industry Corporation, Liaoyang 111000, China
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Safira AR, Kaseem M. Interfacial and Electronic Modulation of M-Bridged Heterostructures with L-Tryptophan and Transition Metallic Oxides: Enhancing Corrosion Resistance and Photocatalytic Activity. ACS APPLIED MATERIALS & INTERFACES 2023; 15:59806-59825. [PMID: 38091515 DOI: 10.1021/acsami.3c14582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2023]
Abstract
Despite remarkable advancements in multilayer composite materials, achieving controlled growth on stationary platforms for optimal corrosion protection and photocatalytic capabilities remains a challenge. In this study, we introduce an innovative approach by integrating bifunctional metal-organic frameworks (MOFs) into plasma-electrolyzed layers made on AZ31 Mg alloy. Metallic oxides of Zr, Ti, and W serve as new pivotal centers for MOF formation, while L-tryptophan (Trp) acts as an organic linker. This innovative approach establishes an efficient electron transport system that acts as a functional pathway for creating highly effective and versatile materials. The tunable structure of the MOF/plasma electrolyzed layer enables it to concurrently display electrochemical stability and photocatalytic activity for the photodegradation of organic pollutants. Remarkably, the WOF complex emerges as a standout performer, effectively shielding the substrate from corrosive anion attacks. This sample showcases exceptional photocatalytic efficiency of 99.61% for crystal violet solution, with sustained performance after five cycles and a 72 h corrosion test (96.55% and 98.39% degradation, respectively). Moreover, DFT calculations elucidate the fundamental bonding modes between MOFs and inorganic constituents, delivering comprehensive insights into their structural formation. Our research addresses the critical challenge of achieving controlled growth for enhanced corrosion resistance and photocatalytic activity, demonstrating a novel pathway for creating multifunctional materials with practical applications across various fields.
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Affiliation(s)
- Ananda Repycha Safira
- Corrosion and Electrochemistry Laboratory, Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 05006, Republic of Korea
| | - Mosab Kaseem
- Corrosion and Electrochemistry Laboratory, Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 05006, Republic of Korea
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6
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Nematov DD, Burhonzoda AS, Kholmurodov KT, Lyubchyk AI, Lyubchyk SI. A Detailed Comparative Analysis of the Structural Stability and Electron-Phonon Properties of ZrO 2: Mechanisms of Water Adsorption on t-ZrO 2 (101) and t-YSZ (101) Surfaces. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2657. [PMID: 37836297 PMCID: PMC10574635 DOI: 10.3390/nano13192657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 09/19/2023] [Accepted: 09/20/2023] [Indexed: 10/15/2023]
Abstract
In this study, we considered the structural stability, electronic properties, and phonon dispersion of the cubic (c-ZrO2), tetragonal (t-ZrO2), and monoclinic (m-ZrO2) phases of ZrO2. We found that the monoclinic phase of zirconium dioxide is the most stable among the three phases in terms of total energy, lowest enthalpy, highest entropy, and other thermodynamic properties. The smallest negative modes were found for m-ZrO2. Our analysis of the electronic properties showed that during the m-t phase transformation of ZrO2, the Fermi level first shifts by 0.125 eV toward higher energies, and then decreases by 0.08 eV in the t-c cross-section. The band gaps for c-ZrO2, t-ZrO2, and m-ZrO2 are 5.140 eV, 5.898 eV, and 5.288 eV, respectively. Calculations based on the analysis of the influence of doping 3.23, 6.67, 10.35, and 16.15 mol. %Y2O3 onto the m-ZrO2 structure showed that the enthalpy of m-YSZ decreases linearly, which accompanies the further stabilization of monoclinic ZrO2 and an increase in its defectiveness. A doping-induced and concentration-dependent phase transition in ZrO2 under the influence of Y2O3 was discovered, due to which the position of the Fermi level changes and the energy gap decreases. It has been established that the main contribution to the formation of the conduction band is made by the p-states of electrons, not only for pure systems, but also those doped with Y2O3. The t-ZrO2 (101) and t-YSZ (101) surface models were selected as optimal surfaces for water adsorption based on a comparison of their surface energies. An analysis of the mechanism of water adsorption on the surface of t-ZrO2 (101) and t-YSZ (101) showed that H2O on unstabilized t-ZrO2 (101) is adsorbed dissociatively with an energy of -1.22 eV, as well as by the method of molecular chemisorption with an energy of -0.69 eV and the formation of a hydrogen bond with a bond length of 1.01 Å. In the case of t-YSZ (101), water is molecularly adsorbed onto the surface with an energy of -1.84 eV. Dissociative adsorption of water occurs at an energy of -1.23 eV, near the yttrium atom. The results show that ab initio approaches are able to describe the mechanism of doping-induced phase transitions in (ZrO2+Y2O3)-like systems, based on which it can be assumed that DFT calculations can also flawlessly evaluate other physical and chemical properties of YSZ, which have not yet been studied quantum chemical research. The obtained results complement the database of research works carried out in the field of the application of biocompatible zirconium dioxide crystals and ceramics in green energy generation, and can be used in designing humidity-to-electricity converters and in creating solid oxide fuel cells based on ZrO2.
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Affiliation(s)
- Dilshod D. Nematov
- Osimi Tajik Technical University, Dushanbe 734042, Tajikistan
- S.U. Umarov Physical-Technical Institute of NAST, Dushanbe 734042, Tajikistan
| | - Amondulloi S. Burhonzoda
- Osimi Tajik Technical University, Dushanbe 734042, Tajikistan
- S.U. Umarov Physical-Technical Institute of NAST, Dushanbe 734042, Tajikistan
| | - Kholmirzo T. Kholmurodov
- Joint Institute for Nuclear Research, 141980 Dubna, Russia
- Dubna State University, 141980 Dubna, Russia
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7
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Jin Y, Sun J, Zhang L, Yang J, Wu Y, You B, Liu X, Leng K, Liu S. Controllable Oxidation of ZrS 2 to Prepare High-κ, Single-Crystal m-ZrO 2 for 2D Electronics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2212079. [PMID: 36815429 DOI: 10.1002/adma.202212079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Revised: 01/27/2023] [Indexed: 05/05/2023]
Abstract
High-κ materials that exhibit large permittivity and band gaps are needed as gate dielectrics to enhance capacitance and prevent leakage current in downsized technology nodes. Among these, monoclinic ZrO2 (m-ZrO2 ) shows good potential because of its inertness and high-κ with respect to SiO2 , but a method to produce ultrathin single crystal is lacking. Here, the controllable preparation of ultrathin m-ZrO2 single crystals via the in situ thermal oxidation of ZrS2 is achieved. As-grown m-ZrO2 presents an equivalent oxide thickness of ≈0.29 nm, a high dielectric constant of ≈19, and a breakdown voltage (EBD ) of ≈7.22 MV cm-1 . MoS2 field effect transistor (FET) by using m-ZrO2 as a dielectric layer shows comparable mobility to that using SiO2 dielectric. The ultraclean interface of m-ZrO2 /MoS2 and high crystalline quality of m-ZrO2 lead to negligible hysteresis in transfer curves. Single crystal m-ZrO2 dielectric shows potential application in digital complementary metal oxidesemiconductor (CMOS) logic FET.
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Affiliation(s)
- Yuanyuan Jin
- State Key Laboratory of Chem/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, P. R. China
- Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, 100872, P. R. China
| | - Jian Sun
- School of Physics and Electronics, Central South University, Changsha, 410083, P. R. China
| | - Ling Zhang
- State Key Laboratory of Chem/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, P. R. China
| | - Junqiang Yang
- School of Physics and Electronics, Central South University, Changsha, 410083, P. R. China
| | - Yangwu Wu
- State Key Laboratory of Chem/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, P. R. China
| | - Bingying You
- Department of Information Technology, Ghent University, Technologiepark-Zwijnaarde 15, Gent, 9052, Belgium
| | - Xiao Liu
- State Key Laboratory of Chem/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, P. R. China
| | - Kai Leng
- Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, 100872, P. R. China
| | - Song Liu
- State Key Laboratory of Chem/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, P. R. China
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Kang SU, Kim CH, You S, Lee DY, Kim YK, Kim SJ, Kim CK, Kim HK. Plasma Surface Modification of 3Y-TZP at Low and Atmospheric Pressures with Different Treatment Times. Int J Mol Sci 2023; 24:7663. [PMID: 37108832 PMCID: PMC10144831 DOI: 10.3390/ijms24087663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 04/07/2023] [Accepted: 04/20/2023] [Indexed: 04/29/2023] Open
Abstract
The efficiency of plasma surface modifications depends on the operating conditions. This study investigated the effect of chamber pressure and plasma exposure time on the surface properties of 3Y-TZP with N2/Ar gas. Plate-shaped zirconia specimens were randomly divided into two categories: vacuum plasma and atmospheric plasma. Each group was subdivided into five subgroups according to the treatment time: 1, 5, 10, 15, and 20 min. Following the plasma treatments, we characterized the surface properties, including wettability, chemical composition, crystal structure, surface morphology, and zeta potential. These were analyzed through various techniques, such as contact angle measurement, XPS, XRD, SEM, FIB, CLSM, and electrokinetic measurements. The atmospheric plasma treatments increased zirconia's electron donation (γ-) capacity, while the vacuum plasma treatments decreased γ- parameter with increasing times. The highest concentration of the basic hydroxyl OH(b) groups was identified after a 5 min exposure to atmospheric plasmas. With longer exposure times, the vacuum plasmas induce electrical damage. Both plasma systems increased the zeta potential of 3Y-TZP, showing positive values in a vacuum. In the atmosphere, the zeta potential rapidly increased after 1 min. Atmospheric plasma treatments would be beneficial for the adsorption of oxygen and nitrogen from ambient air and the generation of various active species on the zirconia surface.
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Affiliation(s)
- Sung Un Kang
- Department of Otolaryngology, School of Medicine, Ajou University, Suwon 16499, Republic of Korea
| | - Chul-Ho Kim
- Department of Otolaryngology, School of Medicine, Ajou University, Suwon 16499, Republic of Korea
- Department of Molecular Science and Technology, Ajou University, Suwon 16499, Republic of Korea
| | - Sanghyun You
- Department of Chemical Engineering, Department of Energy Systems Research, Ajou University, Suwon 16499, Republic of Korea
| | - Da-Young Lee
- Department of Chemistry, Department of Energy Systems Research, Ajou University, Suwon 16499, Republic of Korea
| | - Yu-Kwon Kim
- Department of Chemistry, Department of Energy Systems Research, Ajou University, Suwon 16499, Republic of Korea
| | - Seung-Joo Kim
- Department of Chemistry, Department of Energy Systems Research, Ajou University, Suwon 16499, Republic of Korea
| | - Chang-Koo Kim
- Department of Chemical Engineering, Department of Energy Systems Research, Ajou University, Suwon 16499, Republic of Korea
| | - Hee-Kyung Kim
- Department of Prosthodontics, Institute of Oral Health Science, School of Medicine, Ajou University, Suwon 16499, Republic of Korea
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Kang DC, Hee Pyen S, Kim EJ, Woo Kim Y, Suh YW, Kim DP, Shin CH, Min HK. Hydrogen-free carbon monoxide production through decomposition of formic acid over a HPW/TiO2 catalyst. J IND ENG CHEM 2023. [DOI: 10.1016/j.jiec.2023.03.056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
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10
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Yaldagard M, Shahbaz M, Kim HW, Kim SS. Ethanol Electro-Oxidation on Catalysts with S-ZrO 2-Decorated Graphene as Support in Fuel Cell Applications. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:3327. [PMID: 36234455 PMCID: PMC9565634 DOI: 10.3390/nano12193327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 09/19/2022] [Accepted: 09/20/2022] [Indexed: 06/16/2023]
Abstract
Direct ethanol fuel cells (DEFCs) are considered the most suitable direct alcohol fuel cell (DAFC) in terms of safety and current density. The obstacle to DEFC commercialization is the low reaction kinetics of ethanol (C2H5OH) oxidation because of the poor performance of the electrocatalyst. In this study, for the first time, graphene nanoplates (GNPs) were coated with sulfated zirconium dioxide (ZrO2) as adequate support for platinum (Pt) catalysts in DEFCs. A Pt/S-ZrO2-GNP electrocatalyst was prepared by a new process, polyol synthesis, using microwave heating. Field emission scanning electron microscope (FESEM) imaging revealed well-dispersed platinum nanoparticles supported on the S-ZrO2-GNP powder. Analysis of the Fourier transform infrared (FTIR) spectrometry confirmed that sulfate modified the surfaces of the sample. In X-ray diffraction (XRD), no effect of S-ZrO2 on the crystallinity net in Pt was found. Pt/S-ZrO2-GNP electrode outperformed those with unsulfated counterparts, primarily for the higher access with electron and proton, confirming sulfonating as a practical approach for increasing the performance, electrocatalytic activity, and carbon monoxide (CO) tolerance in an electrocatalyst. A considerable decrease in the voltage of the CO electrooxidation peak from 0.93 V for Pt/C to 0.76 V for the Pt/S-ZrO2-GNP electrode demonstrates that the new material increases activity for CO electrooxidation. Moreover, the as-prepared Pt/S-ZrO2-GNPs electrocatalyst exhibits high catalytic activity for the EOR in terms of electrochemical surface area with respect to Pt/ZrO2-GNPs and Pt/C (199.1 vs. 95 and 67.2 cm2.mg-1 Pt), which may be attributed to structural changes caused by the high specific surface area of graphene nanoplates catalyst support and sulfonating effect as mentioned above. Moreover, EIS results showed that the Pt/S-ZrO2-GNPs electrocatalyst has a lower charge transfer resistance than Pt/ ZrO2-GNPs and Pt/C in the presence of ethanol demonstrating an increased ethanol oxidation activity and reaction kinetics by Pt/S-ZrO2-GNPs.
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Affiliation(s)
- Maryam Yaldagard
- Department of Chemical Engineering, Faculty of Engineering, Urmia University, Urmia 5766-151818, Iran
| | - Mehrdard Shahbaz
- Department of Materials Science and Engineering, Faculty of Engineering, Urmia University, Urmia 5766-151818, Iran
| | - Hyoun Woo Kim
- Division of Materials Science and Engineering, Hanyang University, Seoul 04763, Korea
| | - Sang Sub Kim
- Department of Materials Science and Engineering, Inha University, Incheon 22212, Korea
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Soto-Arteaga CE, Guzmán-Cruz MA, Esqueda-Barron Y, Alonso-Nuñez G, Zepeda TA, Fuentes-Moyado S, Díaz de León JN. Triblock Copolymer Effect During the Synthesis of ZrO2-TiO2 Mixed Oxides Supports for NiW Hydrodesulfurization Catalysts. Top Catal 2022. [DOI: 10.1007/s11244-022-01649-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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12
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Delarmelina M, Catlow CRA. Cation-doping strategies for tuning of zirconia acid-base properties. ROYAL SOCIETY OPEN SCIENCE 2022; 9:211423. [PMID: 35223057 PMCID: PMC8864357 DOI: 10.1098/rsos.211423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 01/14/2022] [Indexed: 05/03/2023]
Abstract
The role of Y-, Ca- and Ce-doping of cubic zirconia (c-ZrO2) (111) surface on its acidity, basicity and the interplay between surface acid-base pairs is investigated by computational methods. The most stable surface structures for this investigation were initially determined based on previous studies of Y-doped c-ZrO2 (111) and by a detailed exploration of the most stable configuration for Ca-doped c-ZrO2 (111) and Ce-doped c-ZrO2 (111). Next, surface mapping by basic probe molecules (NH3 and pyridine) revealed a general reduction of the acidity of the surface sites, although a few exceptions were observed for zirconium ions at next nearest neighbour (NNN) positions to the oxygen vacancy and at the nearest neighbour (NN) position to the dopants. Adsorption of CO2 over basic sites revealed a cooperative interplay between acid-base groups. In this case, the overall effect observed was the decrease of the calculated adsorption energies when compared with the pristine surface. Moreover, spontaneous formation of η 3-CO2 systems from initial η 2-CO2 configurations indicates a decrease in the required energy for forming oxygen vacancies in the doped ZrO2 systems at NNN positions or further away from the existing vacancy site.
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Affiliation(s)
- Maicon Delarmelina
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, UK
- UK Catalysis Hub, Research Complex at Harwell, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0FA, UK
| | - C. Richard A. Catlow
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, UK
- UK Catalysis Hub, Research Complex at Harwell, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0FA, UK
- Department of Chemistry, University College London, 20 Gordon Street, London WC1 HOAJ, UK
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Catalytic Pyrolysis of Lignin Model Compound (Ferulic Acid) over Alumina: Surface Complexes, Kinetics, and Mechanisms. Catalysts 2021. [DOI: 10.3390/catal11121508] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Studies of the thermochemical properties of the important model compound of lignin-ferulic acid (FA) and its surface complexes are substantial for developing technologies for catalytic pyrolysis of renewable biomass into biofuels and lignin-derived chemicals as well as for bio-oil upgrading. In this work, the catalytic pyrolysis of ferulic acid over alumina was studied by temperature-programmed desorption mass spectrometry (TPD MS), in situ FT-IR spectroscopy, thermogravimetric analysis, and DFT calculations. We established that both the carboxyl group and the active groups (HO and CH3O) of the aromatic ring interact with the alumina surface. We calculated the kinetic parameters of formation of the main products of catalytic pyrolysis: 4-vinylguaiacol, guaiacol, hydroxybenzene, benzene, toluene, cresol, naphthalene, and PACs. Possible methods of their forming from the related surface complexes of FA are suggested.
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Decarboxylation of p-Coumaric Acid during Pyrolysis on the Nanoceria Surface. COLLOIDS AND INTERFACES 2021. [DOI: 10.3390/colloids5040048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Temperature-programmed desorption mass spectrometry (TPD MS) was used to study the pyrolysis of p-coumaric acid (pCmA) on the nanoceria surface. The interaction of pCmA with the CeO2 surface was investigated by FT-IR spectroscopy. The obtained data indicated the formation on the nanoceria surface of bidentate carboxylate complexes with chelate (Δν = 62 cm−1) and bridge structure (Δν = 146 cm−1). The thermal decomposition of pCmA over nanoceria occurred in several stages, mainly by decarboxylation. The main decomposition product is 4-vinylphenol (m/z 120). The obtained data can be useful for studying the mechanisms of catalytic thermal transformations of lignin-containing raw materials using catalysts containing cerium oxide and the development of effective technologies for the isolation of pCmA from lignin.
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Catalytic Pyrolysis of Aliphatic Carboxylic Acids into Symmetric Ketones over Ceria-Based Catalysts: Kinetics, Isotope Effect and Mechanism. Catalysts 2020. [DOI: 10.3390/catal10020179] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Ketonization is a promising way for upgrading bio-derived carboxylic acids from pyrolysis bio-oils, waste oils, and fats to produce high value-added chemicals and biofuels. Therefore, an understanding of its mechanism can help to carry out the catalytic pyrolysis of biomass more efficiently. Here we show that temperature-programmed desorption mass spectrometry (TPD-MS) together with linear free energy relationships (LFERs) can be used to identify catalytic pyrolysis mechanisms. We report the kinetics of the catalytic pyrolysis of deuterated acetic acid and a reaction series of linear and branched fatty acids into symmetric ketones on the surfaces of ceria-based oxides. A structure–reactivity correlation between Taft’s steric substituent constants Es* and activation energies of ketonization indicates that this reaction is the sterically controlled reaction. Surface D3-n-acetates transform into deuterated acetone isotopomers with different yield, rate, E≠, and deuterium kinetic isotope effect (DKIE). The obtained values of inverse DKIE together with the structure–reactivity correlation support a concerted mechanism over ceria-based catalysts. These results demonstrate that analysis of Taft’s correlations and using simple equation for estimation of DKIE from TPD-MS data are promising approaches for the study of catalytic pyrolysis mechanisms on a semi-quantitative level.
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