Pub Date : 2024-11-20DOI: 10.1016/j.jallcom.2024.177610
Yu Wang, Yijun Jiang, Yangyang Yuan, Li Xu, Wanting Sun, Si Wu, Wang Qingmiao, Ning Hu, Li Wang
In this study, Ni was severed as a promoter and impregnated on hydroxyapatite (HAP) to prepare a Ni-doped HAP support, and then Ru was highly dispersed onto the Ni-HAP through urea precipitation method. The synergistic effects between Ru and Ni caused a reduction in the particle size of Ru nanoparticles and an increased Ru4+/Ru0 ratios, which was primarily attributed to the strong interaction between the active components and functional groups of OH- and PO43-. Meanwhile, Ru/Ni-HAP possessed the highest amount of medium-strength acid sites and relatively low reduction temperatures, indicating the critical balance between acidity and redox capability. Ru/Ni-HAP exhibited superior activity with complete conversion of toluene at 280 °C and DCM at 400 °C, respectively, and such high activity can be maintained throughout the stability tests. Besides, optimal catalytic performance was observed under 600 ppm concentrations of toluene and DCM with a space velocity of 40,000 mL(g·h)-1. These findings can provide valuable insights for the development of chlorine-resistant catalysts with promising application prospects.
{"title":"Enhanced catalytic combustion of complex VOCs over Ru/Ni-HAP catalyst: Insights into the synergic effects of Ru and Ni species","authors":"Yu Wang, Yijun Jiang, Yangyang Yuan, Li Xu, Wanting Sun, Si Wu, Wang Qingmiao, Ning Hu, Li Wang","doi":"10.1016/j.jallcom.2024.177610","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177610","url":null,"abstract":"In this study, Ni was severed as a promoter and impregnated on hydroxyapatite (HAP) to prepare a Ni-doped HAP support, and then Ru was highly dispersed onto the Ni-HAP through urea precipitation method. The synergistic effects between Ru and Ni caused a reduction in the particle size of Ru nanoparticles and an increased Ru<sup>4+</sup>/Ru<sup>0</sup> ratios, which was primarily attributed to the strong interaction between the active components and functional groups of OH<sup>-</sup> and PO<sub>4</sub><sup>3-</sup>. Meanwhile, Ru/Ni-HAP possessed the highest amount of medium-strength acid sites and relatively low reduction temperatures, indicating the critical balance between acidity and redox capability. Ru/Ni-HAP exhibited superior activity with complete conversion of toluene at 280 °C and DCM at 400 °C, respectively, and such high activity can be maintained throughout the stability tests. Besides, optimal catalytic performance was observed under 600 ppm concentrations of toluene and DCM with a space velocity of 40,000<!-- --> <!-- -->mL(g·h)<sup>-1</sup>. These findings can provide valuable insights for the development of chlorine-resistant catalysts with promising application prospects.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"252 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142678255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Over the last decade, the first two-dimensional transition metal dichalcogenide, MoS2, has been extensively investigated for developing efficient photodetectors due to its tunable bandgap, strong light interaction, high carrier mobility, and large optical transparency. Recently, it has also been integrated with different dimensional materials to improve its optoelectronic behavior. Among the possible heterostructures, MoS2/Si heterojunction-based photodetectors have grabbed huge attention from the scientific fraternity due to their strong light absorption over a broad spectrum and fast carrier transport at the heterointerface. However, none of the existing review articles have addressed the significant contribution of MoS2/Si heterostructures in the field of photodetectors. Therefore, in this article, we are highlighting the recent advances, prospects, and challenges of MoS2/Si heterostructure-based photodetectors for bridging the existing gap. This paper provides a comprehensive analysis of the latest advancements on MoS2/Si heterostructures-based devices, with a specific focus on photodetectors. The carrier dynamics at the MoS2/Si heterointerface and the strategies for improving the performance of devices for developing efficient photodetectors are also highlighted in this report. Finally, we presented a perspective on future opportunities and current challenges for designing mixed-dimensional heterostructures-based photodetectors.
{"title":"A critical review of recent advances, prospects, and challenges of MoS2/Si heterostructure based photodetectors","authors":"Neeraj Goel, Aditya Kushwaha, Smridhi Agarwal, Nitin Babu Shinde","doi":"10.1016/j.jallcom.2024.177692","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177692","url":null,"abstract":"Over the last decade, the first two-dimensional transition metal dichalcogenide, MoS<sub>2</sub>, has been extensively investigated for developing efficient photodetectors due to its tunable bandgap, strong light interaction, high carrier mobility, and large optical transparency. Recently, it has also been integrated with different dimensional materials to improve its optoelectronic behavior. Among the possible heterostructures, MoS<sub>2</sub>/Si heterojunction-based photodetectors have grabbed huge attention from the scientific fraternity due to their strong light absorption over a broad spectrum and fast carrier transport at the heterointerface. However, none of the existing review articles have addressed the significant contribution of MoS<sub>2</sub>/Si heterostructures in the field of photodetectors. Therefore, in this article, we are highlighting the recent advances, prospects, and challenges of MoS<sub>2</sub>/Si heterostructure-based photodetectors for bridging the existing gap. This paper provides a comprehensive analysis of the latest advancements on MoS<sub>2</sub>/Si heterostructures-based devices, with a specific focus on photodetectors. The carrier dynamics at the MoS<sub>2</sub>/Si heterointerface and the strategies for improving the performance of devices for developing efficient photodetectors are also highlighted in this report. Finally, we presented a perspective on future opportunities and current challenges for designing mixed-dimensional heterostructures-based photodetectors.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"2 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142678258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-20DOI: 10.1016/j.jallcom.2024.177682
Yeon-Ji Jeon, Seung Won Lee, Yoonchul Shin, Ji-Hwan Kim, Chang Mo Yoon, Ji-Hoon Ahn
ZrO2 films with ultrathin Al2O3 layers have effectively contributed to the miniaturization of dynamic random access memory (DRAM) capacitors for many years. However, as memory devices continue to shrink, higher dielectric constants are required to maintain cell capacitance. To address this challenge, research has explored the use of tetragonal HfO2 layers, which theoretically possess a higher dielectric constant than ZrO2, as dielectrics. However, the thermodynamically stable phase of HfO2 is monoclinic with a lower dielectric constant, necessitating a phase transition to the tetragonal form for DRAM capacitor applications. Although attempts have been made to induce this phase transition to achieve high dielectric constants by applying an HfO2/ZrO2 layered structure or doping HfO2 with elements such as Zr, Al, and Si, significant challenges remain in completely eliminating the monoclinic phase or implementing a pure tetragonal phase of HfO2. In this study, we systematically investigated the crystallinity changes and improved the electrical properties of HfO2/ZrO2 layered structures with Al doping in the HfO2 layers. Our findings demonstrate that optimizing the partitioning of the ZrO2 and HfO2 layers, combined with Al doping, effectively achieves equivalent oxide thickness scaling.
{"title":"Effect of Al doping on structural and electrical properties of HfO2/ZrO2 layered structures for high-k applications","authors":"Yeon-Ji Jeon, Seung Won Lee, Yoonchul Shin, Ji-Hwan Kim, Chang Mo Yoon, Ji-Hoon Ahn","doi":"10.1016/j.jallcom.2024.177682","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177682","url":null,"abstract":"ZrO<sub>2</sub> films with ultrathin Al<sub>2</sub>O<sub>3</sub> layers have effectively contributed to the miniaturization of dynamic random access memory (DRAM) capacitors for many years. However, as memory devices continue to shrink, higher dielectric constants are required to maintain cell capacitance. To address this challenge, research has explored the use of tetragonal HfO<sub>2</sub> layers, which theoretically possess a higher dielectric constant than ZrO<sub>2</sub>, as dielectrics. However, the thermodynamically stable phase of HfO<sub>2</sub> is monoclinic with a lower dielectric constant, necessitating a phase transition to the tetragonal form for DRAM capacitor applications. Although attempts have been made to induce this phase transition to achieve high dielectric constants by applying an HfO<sub>2</sub>/ZrO<sub>2</sub> layered structure or doping HfO<sub>2</sub> with elements such as Zr, Al, and Si, significant challenges remain in completely eliminating the monoclinic phase or implementing a pure tetragonal phase of HfO<sub>2</sub>. In this study, we systematically investigated the crystallinity changes and improved the electrical properties of HfO<sub>2</sub>/ZrO<sub>2</sub> layered structures with Al doping in the HfO<sub>2</sub> layers. Our findings demonstrate that optimizing the partitioning of the ZrO<sub>2</sub> and HfO<sub>2</sub> layers, combined with Al doping, effectively achieves equivalent oxide thickness scaling.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"46 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
High entropy carbide ceramics, known for their single-phase formation and tunable properties, have seen limited research on regulating the performance of powders and coatings through elemental changes. This study focused on how different elements affect high entropy phase. Two reaction systems were established using precursors Ta2O5, ZrO2, Nb2O5, TiO2, V2O5, MoO3, and carbon black to explore the impact of two elements on the formation of high-entropy carbide. The (TaZrTiNbV)C and (TaMoTiNbV)C dense coatings were prepared by plasma spraying. The influences of two elements (Zr and Mo) on the phase, microstructure, property, and formation mechanism of the coating were analyzed. The (TaZrTiNbV)C coating showing a hardness of 1762 HV0.1 and a toughness of 3.1 MPa·m1/2, which were attributed to the presence of finely-grained (TaZrTiNbV)C particles.
{"title":"The influence of metal element types on the formation mechanism and properties of high-entropy ceramic powders and coatings","authors":"Wen-wei Sun, Yi Hu, Yong Yang, Hong-jian Zhao, Yan-wei Wang, Wei Li, Yu-xuan Shao, Pei-wen Ru, Yu-duo Ma, Sheng-yong Gao, Ai-min Li, Huan-huan Zhang","doi":"10.1016/j.jallcom.2024.177680","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177680","url":null,"abstract":"High entropy carbide ceramics, known for their single-phase formation and tunable properties, have seen limited research on regulating the performance of powders and coatings through elemental changes. This study focused on how different elements affect high entropy phase. Two reaction systems were established using precursors Ta<sub>2</sub>O<sub>5</sub>, ZrO<sub>2</sub>, Nb<sub>2</sub>O<sub>5</sub>, TiO<sub>2</sub>, V<sub>2</sub>O<sub>5</sub>, MoO<sub>3</sub>, and carbon black to explore the impact of two elements on the formation of high-entropy carbide. The (TaZrTiNbV)C and (TaMoTiNbV)C dense coatings were prepared by plasma spraying. The influences of two elements (Zr and Mo) on the phase, microstructure, property, and formation mechanism of the coating were analyzed. The (TaZrTiNbV)C coating showing a hardness of 1762 HV<sub>0.1</sub> and a toughness of 3.1<!-- --> <!-- -->MPa·m<sup>1/2</sup>, which were attributed to the presence of finely-grained (TaZrTiNbV)C particles.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"2 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142678950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The high-value utilization of steel pickling waste liquid (SPWL) is an important direction in the resourceful utilization of hazardous waste. In this study, nano-Fe3O4 prepared from SPWL (S-Fe3O4) was hydrothermally compounded with MnO2 as Fe3O4-MnO2 (SFM), which were compared with Fe3O4-MnO2 (CFM) prepared by chemical reagents. The synthetic materials were evaluated by SEM, VSM, BET, XRD, and zeta potential, the results show that the spherical S-Fe3O4 was encapsulated by spiny spherical shell-like MnO2, and the SFM has a high saturation magnetization and specific surface area (159.91 m2/g). The adsorption experiments demonstrated that the adsorption effect of SFM on Pb2+ is highly similar to that of CFM. The maximal adsorption capacity of SFM reached 129.74 mg/g under ideal composite ratio and pH conditions, and the adsorption process was unaffected by competing heavy metal ions coexisting in the environment. Moreover, the high saturation magnetization strength of the SFM makes it simple to separate materials under a magnetic field. The pseudo-second-order kinetics and Langmuir isotherm models provided a good description of the Pb2+ adsorption on SFM. XPS and FTIR analysis provided evidence that the adsorbent surface has a high concentration of -OH functional groups, and that O atoms serve as Pb2+ binding sites, suggesting that ion exchange occurs during the SFM adsorption process. In this paper, we developed a cheap SFM with high adsorption performance and provided a novel approach to the high-value application of SPWL.
{"title":"Effective removal of Pb2+ from water by a novel magnetic Fe3O4-MnO2 composite prepared from steel pickling waste liquid: adsorption behavior and mechanism","authors":"Yingying Fang, Wenbo Zhou, Yihuan Cheng, Yuge Zhang, Tingting Yu, Shaoxian Song","doi":"10.1016/j.jallcom.2024.177685","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177685","url":null,"abstract":"The high-value utilization of steel pickling waste liquid (SPWL) is an important direction in the resourceful utilization of hazardous waste. In this study, nano-Fe<sub>3</sub>O<sub>4</sub> prepared from SPWL (S-Fe<sub>3</sub>O<sub>4</sub>) was hydrothermally compounded with MnO<sub>2</sub> as Fe<sub>3</sub>O<sub>4</sub>-MnO<sub>2</sub> (SFM), which were compared with Fe<sub>3</sub>O<sub>4</sub>-MnO<sub>2</sub> (CFM) prepared by chemical reagents. The synthetic materials were evaluated by SEM, VSM, BET, XRD, and zeta potential, the results show that the spherical S-Fe<sub>3</sub>O<sub>4</sub> was encapsulated by spiny spherical shell-like MnO<sub>2</sub>, and the SFM has a high saturation magnetization and specific surface area (159.91 m<sup>2</sup>/g). The adsorption experiments demonstrated that the adsorption effect of SFM on Pb<sup>2+</sup> is highly similar to that of CFM. The maximal adsorption capacity of SFM reached 129.74<!-- --> <!-- -->mg/g under ideal composite ratio and pH conditions, and the adsorption process was unaffected by competing heavy metal ions coexisting in the environment. Moreover, the high saturation magnetization strength of the SFM makes it simple to separate materials under a magnetic field. The pseudo-second-order kinetics and Langmuir isotherm models provided a good description of the Pb<sup>2+</sup> adsorption on SFM. XPS and FTIR analysis provided evidence that the adsorbent surface has a high concentration of -OH functional groups, and that O atoms serve as Pb<sup>2+</sup> binding sites, suggesting that ion exchange occurs during the SFM adsorption process. In this paper, we developed a cheap SFM with high adsorption performance and provided a novel approach to the high-value application of SPWL.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"22 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Herein, we synthesized a Cu2O and Co3O4 incorporation with MoS2 to produce MoS2/Co3O4/Cu2O nanocomposites by facile sonication assisted hydrothermal methods. The phase structure and elemental composition of MoS2/Co3O4/Cu2O nanocomposites were investigated using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) morphology studies confirm that MoS2/Co3O4 nanostructure self-assembles in a mixed nanosheet configuration after the introduction of Cu2O. The synthesized samples were used as new types of Pt-free counter electrodes (CE) for DSSCs. Among all, the DSSCs based on the MoS2/Co3O4/Cu2O CE yields a maximum power conversion efficiency of 3.68% (Jsc = 8.2 mA cm-2, Voc = 0.71 mV and FF = 0.629%) under the standard AM 1.5 G illumination, which is 2.5 times higher than that of pure MoS2. To assess the photocatalytic activity, prepared samples were used to suppress methylene blue (MB) and rhodamine B (RhB) dye under UV-visible light irradiation. The MoS2/Co3O4/Cu2O nanocomposites had the highest photocatalytic degradation efficiency of all the samples. It increased degradation efficiency from 43% to 91% for MB dye after 100 minutes, and from 47% to 92% for RhB dye after 90 minutes. Scavengers test analysis proved that the superoxide radical (•O2-) play a major role in the MoS2/Co3O4/Cu2O photocatalytic system. After four consecutive photocatalytic cycles, the crystal structure and surface morphology of the MoS2/Co3O4/Cu2O nanocomposites used in the 4th cycle were more stable, and this was confirmed by SEM, EDAX and XRD studies. The broader significance of these findings provides a straightforward approach for synthesizing a low-cost and high-efficiency MoS2/Co3O4/Cu2O nanocomposite for CE in DSSC photovoltaic cells and facilitates organic pollutant removal through photocatalytic applications.
{"title":"Synergistic Effects in MoS2/Co3O4/Cu2O Nanocomposites for Superior Solar Cell and Photodegradation Efficiency","authors":"Karthigaimuthu Dharmalingam, Arjun Kumar Bojarajan, Elangovan Thangavel, Pardha Saradhi Maram, Sasirekha Venkidusamy, Sambasivam Sangaraju, Abdel-Hamid I. Mourad","doi":"10.1016/j.jallcom.2024.177672","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177672","url":null,"abstract":"Herein, we synthesized a Cu<sub>2</sub>O and Co<sub>3</sub>O<sub>4</sub> incorporation with MoS<sub>2</sub> to produce MoS<sub>2</sub>/Co<sub>3</sub>O<sub>4</sub>/Cu<sub>2</sub>O nanocomposites by facile sonication assisted hydrothermal methods. The phase structure and elemental composition of MoS<sub>2</sub>/Co<sub>3</sub>O<sub>4</sub>/Cu<sub>2</sub>O nanocomposites were investigated using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) morphology studies confirm that MoS<sub>2</sub>/Co<sub>3</sub>O<sub>4</sub> nanostructure self-assembles in a mixed nanosheet configuration after the introduction of Cu<sub>2</sub>O. The synthesized samples were used as new types of Pt-free counter electrodes (CE) for DSSCs. Among all, the DSSCs based on the MoS<sub>2</sub>/Co<sub>3</sub>O<sub>4</sub>/Cu<sub>2</sub>O CE yields a maximum power conversion efficiency of 3.68% (J<sub>sc</sub> = 8.2<!-- --> <!-- -->mA<!-- --> <!-- -->cm<sup>-2</sup>, V<sub>oc</sub> = 0.71<!-- --> <!-- -->mV and FF = 0.629%) under the standard AM 1.5<!-- --> <!-- -->G illumination, which is 2.5 times higher than that of pure MoS<sub>2</sub>. To assess the photocatalytic activity, prepared samples were used to suppress methylene blue (MB) and rhodamine B (RhB) dye under UV-visible light irradiation. The MoS<sub>2</sub>/Co<sub>3</sub>O<sub>4</sub>/Cu<sub>2</sub>O nanocomposites had the highest photocatalytic degradation efficiency of all the samples. It increased degradation efficiency from 43% to 91% for MB dye after 100<!-- --> <!-- -->minutes, and from 47% to 92% for RhB dye after 90<!-- --> <!-- -->minutes. Scavengers test analysis proved that the superoxide radical (•O<sub>2</sub><sup>-</sup>) play a major role in the MoS<sub>2</sub>/Co<sub>3</sub>O<sub>4</sub>/Cu<sub>2</sub>O photocatalytic system. After four consecutive photocatalytic cycles, the crystal structure and surface morphology of the MoS<sub>2</sub>/Co<sub>3</sub>O<sub>4</sub>/Cu<sub>2</sub>O nanocomposites used in the 4th cycle were more stable, and this was confirmed by SEM, EDAX and XRD studies. The broader significance of these findings provides a straightforward approach for synthesizing a low-cost and high-efficiency MoS<sub>2</sub>/Co<sub>3</sub>O<sub>4</sub>/Cu<sub>2</sub>O nanocomposite for CE in DSSC photovoltaic cells and facilitates organic pollutant removal through photocatalytic applications.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"57 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-20DOI: 10.1016/j.jallcom.2024.177683
Jie Zhang, Zekui Zhang, Lu Liu, Han Zhang, Tian Xing, Kexun Li, Ruihua Zhao, Jianping Du
The lightweight, strong absorption, non-resin, and high chemical and thermal stability of electromagnetic wave absorption materials used in space vehicles are required in the harsh space environments. Herein, a light weight and effective microwave-absorbing material is constructed by synthesizing carbide-modified reduced graphene oxide (rGO) aerogels, gradient design and carbonization. The as-prepared aerogel material consists of molybdenum carbide (MC) and rGO, and displays hollow structures with multi-wall rGO layers. The MC structure in the MC/rGO aerogel is regulated by controlling the amount of Mo source, and the dual gradient structure composed of MC/rGOmaterial is designed and optimized by CST Microwave Studio. Compared with MC/rGO aerogel, the dual-gradient MC/rGO (DG-MC/rGO) aerogel exhibits superior impedance matching and significantly enhanced microwave absorption performance. The minimum reflection loss (-62.4 dB) is reduced by 64.6%, and the effective absorption bandwidth (5.7 GHz) is increased by over 35.7% at a thickness of 2.2 mm. The remarkable improvement of microwave absorption is attributed to the synergy effect of well-dispersed molybdenum carbide nanoparticles and the components/structures gradients of DG-MC/rGO material. This novel lightweight material has promising applications in electromagnetic wave absorption fields.
{"title":"Dual-gradient Mo2C-decorated rGO aerogels for enhanced electromagnetic wave absorption","authors":"Jie Zhang, Zekui Zhang, Lu Liu, Han Zhang, Tian Xing, Kexun Li, Ruihua Zhao, Jianping Du","doi":"10.1016/j.jallcom.2024.177683","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177683","url":null,"abstract":"The lightweight, strong absorption, non-resin, and high chemical and thermal stability of electromagnetic wave absorption materials used in space vehicles are required in the harsh space environments. Herein, a light weight and effective microwave-absorbing material is constructed by synthesizing carbide-modified reduced graphene oxide (rGO) aerogels, gradient design and carbonization. The as-prepared aerogel material consists of molybdenum carbide (MC) and rGO, and displays hollow structures with multi-wall rGO layers. The MC structure in the MC/rGO aerogel is regulated by controlling the amount of Mo source, and the dual gradient structure composed of MC/rGOmaterial is designed and optimized by CST Microwave Studio. Compared with MC/rGO aerogel, the dual-gradient MC/rGO (DG-MC/rGO) aerogel exhibits superior impedance matching and significantly enhanced microwave absorption performance. The minimum reflection loss (-62.4<!-- --> <!-- -->dB) is reduced by 64.6%, and the effective absorption bandwidth (5.7<!-- --> <!-- -->GHz) is increased by over 35.7% at a thickness of 2.2<!-- --> <!-- -->mm. The remarkable improvement of microwave absorption is attributed to the synergy effect of well-dispersed molybdenum carbide nanoparticles and the components/structures gradients of DG-MC/rGO material. This novel lightweight material has promising applications in electromagnetic wave absorption fields.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"10 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-20DOI: 10.1016/j.jallcom.2024.177633
Changjiang Zhang, Yijie Hang, Pengkun Guo, Ruipeng Guo, Hong Feng, Jianchao Han, Zhixiong Zhang, Tao Wang, Fan Peng, Shuzhi Zhang, Xinyu Zhang
The tread-off between the strength and ductility of near-β titanium alloys has significantly limited their applications. In this study, a novel near-β titanium alloy containing Si element was designed, and the influence of α-phase spheroidization and silicide precipitation on the mechanical properties was investigated during isothermal multi-directional forging (IMDF) process. The results showed that the β grain is easy to deform and elongate, and the deformed alloy mainly undergoes dynamic recovery (DRV) rather than dynamic recrystallization (DRX). Some silicides are dissolved due to the temperature rise caused by IMDF and the diffusion of atoms on the top of the irregularly shaped silicides. Zr and Si elements are redistributed and segregated at the dislocation, resulting in the formation of submicron-scale and nano-scale silicides. Lath-like αp phase will precipitate from the prior β grain after heat treatment in the dual-phase region, and the volume fraction of αp phase increases with the decrease of heat treatment temperature. In addition, rotation deformation and spheroidization of the lath-like αp phase occur during multi-pass IMDF in the dual-phase region. When multi-pass IMDF temperature is 770 ℃, the silicide distribution is uniform, and the αp phases are equiaxed, which is conducive to the improvement of ductility. The obtained results provide a new way to prepare the Si-containing near-β titanium alloys with excellent mechanical properties.
{"title":"The silicide precipitation mechanism and spheroidization behavior of αp phase in a novel near-β titanium alloy during isothermal multi-directional forging process","authors":"Changjiang Zhang, Yijie Hang, Pengkun Guo, Ruipeng Guo, Hong Feng, Jianchao Han, Zhixiong Zhang, Tao Wang, Fan Peng, Shuzhi Zhang, Xinyu Zhang","doi":"10.1016/j.jallcom.2024.177633","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177633","url":null,"abstract":"The tread-off between the strength and ductility of near-β titanium alloys has significantly limited their applications. In this study, a novel near-β titanium alloy containing Si element was designed, and the influence of α-phase spheroidization and silicide precipitation on the mechanical properties was investigated during isothermal multi-directional forging (IMDF) process. The results showed that the β grain is easy to deform and elongate, and the deformed alloy mainly undergoes dynamic recovery (DRV) rather than dynamic recrystallization (DRX). Some silicides are dissolved due to the temperature rise caused by IMDF and the diffusion of atoms on the top of the irregularly shaped silicides. Zr and Si elements are redistributed and segregated at the dislocation, resulting in the formation of submicron-scale and nano-scale silicides. Lath-like α<sub>p</sub> phase will precipitate from the prior β grain after heat treatment in the dual-phase region, and the volume fraction of α<sub>p</sub> phase increases with the decrease of heat treatment temperature. In addition, rotation deformation and spheroidization of the lath-like α<sub>p</sub> phase occur during multi-pass IMDF in the dual-phase region. When multi-pass IMDF temperature is 770 ℃, the silicide distribution is uniform, and the α<sub>p</sub> phases are equiaxed, which is conducive to the improvement of ductility. The obtained results provide a new way to prepare the Si-containing near-β titanium alloys with excellent mechanical properties.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"64 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673339","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Due to the relatively small particle size of single crystals, the high specific surface area increases the side reactions between the electrode and the electrolyte. Without proper surface modification, single-crystal particles tend to interact directly with the electrolyte, leading to side reactions that impair the electrochemical performance of the material. To address this issue, constructing a coating layer on the material's surface is one effective solution. In this study, a wet-coating technique was employed to co-coat single-crystal LiNi0.5Co0.2Mn0.3O2 cathode material with vanadium (V) and samarium (Sm). SEM and TEM tests revealed the presence of a V-Sm coating layer with a thickness of approximately 1-3 nm on the surface of the coated samples. The coated material demonstrated a capacity retention rate of 86.5% after 450 cycles at a 1 C rate (1 C=160 mAh·g-1), which represents an improvement of about 6.7% compared to the original material. EIS results indicated that the V-Sm coating stabilized the surface SEI film of the material and inhibited the growth of charge transfer resistance (Rct). XPS analysis of the electrodes after cycling showed that the V-Sm coating effectively protected the material by isolating it from direct contact with the electrolyte, suppressing the decomposition of the electrolyte during cycling, and reducing adverse side reactions between the material and the electrolyte, thereby enhancing the overall electrochemical performance of the material.
由于单晶的粒径相对较小，高比表面积会增加电极与电解质之间的副反应。如果不进行适当的表面改性，单晶颗粒往往会直接与电解质发生作用，从而导致副反应，损害材料的电化学性能。为解决这一问题，在材料表面构建涂层是一种有效的解决方案。本研究采用湿涂层技术在单晶 LiNi0.5Co0.2Mn0.3O2 阴极材料表面镀上了钒（V）和钐（Sm）。SEM 和 TEM 测试显示，涂层样品表面存在厚度约为 1-3 nm 的 V-Sm 涂层。涂层材料在 1 C 速率（1 C=160 mAh-g-1）下循环 450 次后，容量保持率达到 86.5%，与原始材料相比提高了约 6.7%。EIS 结果表明，V-Sm 涂层稳定了材料表面的 SEI 膜，抑制了电荷转移电阻（Rct）的增长。对电极进行循环后的 XPS 分析表明，V-Sm 涂层有效地保护了材料，使其与电解液隔绝直接接触，抑制了循环过程中电解液的分解，减少了材料与电解液之间的不良副反应，从而提高了材料的整体电化学性能。
{"title":"Study on the Surface Modification of Regenerated and Repaired LiNi0.5Co0.2Mn0.3O2 Single Crystal","authors":"Jiaxing Han, Weijian Zhang, Yuhui Zhao, Zongbing Chen, Wei Zhang, Yingqing Bao, Xiaozhen Wu, Aigang Zhen, Na Li, Binglong Zhu, Yan Zhuang","doi":"10.1016/j.jallcom.2024.177689","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177689","url":null,"abstract":"Due to the relatively small particle size of single crystals, the high specific surface area increases the side reactions between the electrode and the electrolyte. Without proper surface modification, single-crystal particles tend to interact directly with the electrolyte, leading to side reactions that impair the electrochemical performance of the material. To address this issue, constructing a coating layer on the material's surface is one effective solution. In this study, a wet-coating technique was employed to co-coat single-crystal LiNi<sub>0.5</sub>Co<sub>0.2</sub>Mn<sub>0.3</sub>O<sub>2</sub> cathode material with vanadium (V) and samarium (Sm). SEM and TEM tests revealed the presence of a V-Sm coating layer with a thickness of approximately 1-3<!-- --> <!-- -->nm on the surface of the coated samples. The coated material demonstrated a capacity retention rate of 86.5% after 450 cycles at a 1<!-- --> <!-- -->C rate (1<!-- --> <!-- -->C=160 mAh·g<sup>-1</sup>), which represents an improvement of about 6.7% compared to the original material. EIS results indicated that the V-Sm coating stabilized the surface SEI film of the material and inhibited the growth of charge transfer resistance (Rct). XPS analysis of the electrodes after cycling showed that the V-Sm coating effectively protected the material by isolating it from direct contact with the electrolyte, suppressing the decomposition of the electrolyte during cycling, and reducing adverse side reactions between the material and the electrolyte, thereby enhancing the overall electrochemical performance of the material.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"8 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-20DOI: 10.1016/j.jallcom.2024.177686
Hong Liu, Wanfeng Zhuang, Ning Chen, Hao Chen, Weiling Wang, Jie Xing, Jianguo Zhu
We achieved ultrahigh temperature stability of the piezoelectric coefficient d33 by doping heterovalent ions in the PbZr0.54Ti0.46O3 ceramics at the A/B sites in the ABO3 lattice. The Sm3+-ion amount at the A-site remains constant, while the Ta5+-ion amount at the B-site changes. We utilized electron paramagnetic resonance (EPR) and X-ray photoelectron spectroscopy (XPS) to investigate the reduction of oxygen vacancies, which are closely associated with the defect dipoles formed by heterovalent doping. We utilized piezoresponse force microscopy (PFM), temperature-dependent X-ray diffraction (XRD) combined with Rietveld refinement, and temperature-dependent Raman spectroscopy to understand the mechanism of the temperature stability of the piezoelectric coefficient d33. When x=0.01, the performance of xTa-0.01Sm-PbZr0.54Ti0.46O3 ceramic is optimal: d33=530 pC/N, electromechanical coupling factor kp=0.72, Curie temperature TC =343 °C, where the temperature stability of the piezoelectric coefficient is ultrahigh, and the d33 changes only 2.2% over the 25−200 °C temperature range.
{"title":"Ultrahigh temperature stability in heterovalent-ion doped PZT ceramics","authors":"Hong Liu, Wanfeng Zhuang, Ning Chen, Hao Chen, Weiling Wang, Jie Xing, Jianguo Zhu","doi":"10.1016/j.jallcom.2024.177686","DOIUrl":"https://doi.org/10.1016/j.jallcom.2024.177686","url":null,"abstract":"We achieved ultrahigh temperature stability of the piezoelectric coefficient <em>d</em><sub>33</sub> by doping heterovalent ions in the PbZr<sub>0.54</sub>Ti<sub>0.46</sub>O<sub>3</sub> ceramics at the A/B sites in the ABO<sub>3</sub> lattice. The Sm<sup>3+</sup>-ion amount at the A-site remains constant, while the Ta<sup>5+</sup>-ion amount at the B-site changes. We utilized electron paramagnetic resonance (EPR) and X-ray photoelectron spectroscopy (XPS) to investigate the reduction of oxygen vacancies, which are closely associated with the defect dipoles formed by heterovalent doping. We utilized piezoresponse force microscopy (PFM), temperature-dependent X-ray diffraction (XRD) combined with Rietveld refinement, and temperature-dependent Raman spectroscopy to understand the mechanism of the temperature stability of the piezoelectric coefficient <em>d</em><sub>33</sub>. When <em>x</em>=0.01, the performance of <em>x</em>Ta-0.01Sm-PbZr<sub>0.54</sub>Ti<sub>0.46</sub>O<sub>3</sub> ceramic is optimal: <em>d</em><sub>33</sub>=530 pC/N, electromechanical coupling factor <em>k</em><sub>p</sub>=0.72, Curie temperature <em>T</em><sub>C</sub> =343 °C, where the temperature stability of the piezoelectric coefficient is ultrahigh, and the <em>d</em><sub>33</sub> changes only 2.2% over the 25−200 °C temperature range.","PeriodicalId":344,"journal":{"name":"Journal of Alloys and Compounds","volume":"46 1","pages":""},"PeriodicalIF":6.2,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673341","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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