JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2018
·Vol. 29
·期 7
·5954-5960
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IF 2.324
Wang Yan,Wang Yishu,Han Jing,Tan Shihai,Guo Fu
Sn grain orientation in solder matrix has recently been considered as one of the principal failure contributions in lead-free solder joints. Since β -Sn exhibits high anisotropy, the differences of electromigration behavior of solder joints with various grain orientations are dramatic. With different angle ( θ ) between the c -axis of Sn grain and the direction of electron flow, the solder joints often demonstrate varying degrees of electromigration-induced damage. The present investigation illustrated significant differences in microstructural features on the surface of Cu reinforced composite solder joints, even with similar angle θ . Two Cu particles reinforced Sn 3.5 Ag composite solder joints with the similar angle θ of 35° and 40° were selected to investigate the effects of Sn grain c -axis on electromigration under high current stressing for 528 h. A large number of Cu 6 Sn 5 compounds were observed and occupied nearly the whole surface with clear polarization effect in one sample. In contrast, very few Cu 6 Sn 5 were found on the surface of the solder matrix in the other sample after current stressing, and the Cu 6 Sn 5 which was formed after reflow disappeared with subsequent current stressing. Even though polarization effect was not obvious, and the cathode interfacial dissolution was observed on such sample. Systematic study revealed that the angle θ alone was not a sole factor to determine the electromigration damage. It has to be considered along with the coordinate system containing the orientation of the c -axis of the Sn grain, a more dominative factor for the diffusing species.
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JOURNAL OF ORGANOMETALLIC CHEMISTRY
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2018
·
IF 1.946
Linna Sha,Peng Gao,Xiaobo Li,Xuefeng Bai
In this work, amorphous CoB has been uniformly coated on C 60 surfaces through a simple ball milling process. Accordingly their XRD , SEM and TEM measurements clarify their related composite structures. Especially, a C-B chemical bond has been found through its XPS measurement, which enhanced the composite's stability and electrochemical activity. And the following electrochemical experimental results demonstrated that the as-obtained C 60 /CoB composite had considerably high storage capacities of 602 mA h/g, which were much higher than those of individual C 60 and CoB. Furthermore their hydrogen storage processes and the mechanism have also been investigated.
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JOURNAL OF THE ENERGY INSTITUTE
·
2024
·
IF 5.6
Bowen Luo,Xiaoxin Chen,Yongxiang Guo,Riyang Shu,Chao Wang,Jianping Liu,Junyao Wang,Zhipeng Tian,Ying Chen
Hydrodeoxygenation (HDO) is a crucial technique for upgrading biomass-derived compounds, playing a significant role in the advancement of sustainable energy technologies. Under harsh reaction conditions, conventional HDO catalysts often suffer from reduced efficiency due to particle aggregation. This study presents a highly efficient Ni/Al 2 O 3 -C catalyst that mitigates this issue by stabilizing Ni metal particles and enhancing metal-support interactions. Characterization of the catalyst was carried out using XRD, TEM, and CO-TPD, which revealed that the incorporation of Al species improved metal dispersion and reduced the size of the Ni particles. Guaiacol, a phenolic compound derived from lignin, was chosen to evaluate the HDO performance under mild conditions. The optimized Ni/3Al 2 O 3 -5C catalyst achieved a guaiacol conversion of 99.9 % with a cyclohexane selectivity of 99.8 % at 210 °C. The outstanding performance is attributed to the high hydrogenation capacity of the small Ni particles and the acid sites on the carbon surface. Metal-support interactions stabilize the Ni particles, preventing leaching and deactivation. The catalyst has also exhibited comparable effectiveness in the HDO of both lignin-derived compounds and lignin-oils, confirming its adaptability across various substrates. The study demonstrates that Al 2 O 3 -C plays a crucial role in enhancing both the structural stability and catalytic efficiency of HDO catalysts, offering a promising approach for upgrading biomass-derived compounds.
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Journal of Materials Chemistry A
·
2025
·
IF 9.5
Jiaqi Huang,Xinglin Tang,Yuqi Zhou,Ting Wang,Fangzhou Zhao,Weijian Wang,Yan Meng,Wanglai Cen,Yongzhi Zhang
The practical application of manganese-rich lithium manganese iron phosphate, i.e., LiMn0.8Fe0.2PO4, is limited by poor cycling stability and severe voltage decay. In this study, a novel and facile Zn-gradient doping strategy has been employed to enhance the structural stability and lithium-ion de-intercalation kinetics, thereby suppressing the voltage decay of LiMn0.8Fe0.2PO4/C (LMFP/C). Compared to the pristine LMFP/C, the Zn-gradient doped LiMn0.8Fe0.2PO4/C (Zn-LMFP/C) exhibits significantly enhanced cycling stability with the capacity retention increasing from 64.11% to 97.47% and suppressed voltage decay with the energy retention increasing from 60.75% to 96.06% after 300 cycles at 1C. Furthermore, the reversible capacity of Zn-LMFP/C is 157.21 mA h g−1 at 0.1C and 138.88 mA h g−1 at 5C, much higher than those of most of the Mn-rich LMFP/C materials reported in previous literature. Cyclic voltammetry (CV) and Galvanostatic Intermittent Titration Technique (GITT) results show that the delithiation/lithiation kinetics of Zn-LMFP/C are notably enhanced. Further first-principles calculations confirm that Zn-LMFP/C possesses superior structural stability and lithium-ion diffusion kinetics. These findings underscore the effectiveness of gradient doping in improving the electrochemical stability of LMFP, providing a promising strategy to mitigate voltage decay and enhance the long-term performance of high-capacity cathode materials for lithium-ion batteries.
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ELECTROCHIMICA ACTA
·
2024
·
IF 5.5
Zhenwu Zhong,Xiaoyu Yang,Zhaoxiang Qi,Ke Zhao,Salman Riaz,Ying Qi,Peng Wei,Min Jae Ko,Jian Cheng,Yahong Xie
Carbon-based MAPbI 3 perovskite solar cells (C-PSCs) have attracted significant attention due to their low cost and stable performance. However, due to inherent structural defects and an energy level mismatch between the perovskite layer and the carbon electrode, C-PSCs still show a poorer power conversion efficiency (PCE) than traditional perovskite solar cells (PSCs). In this study, LaFeO 3 @C nanocomposite particles were successfully synthesized via pyrolysis of La-containing MIL-100(Fe) MOF gel. By introducing these pre-synthesized LaFeO 3 @C bimetallic composite oxide nanoparticles into the carbon electrode, the device featuring a FTO/SnO 2 /CH 3 NH 3 PbI 3 /LaFeO 3 @C/C architecture achieved an impressive maximum PCE of 16.35%, surpassing that of the pristine device by 9.36%. The enhanced optoelectronic performance can be primarily attributed to enhanced interfacial contacts, superior interfacial charge extraction ability, and better electrical conductivity . The LaFeO 3 @C-based device maintained more than 90% of the initial PCE after being stored for 31 days at room temperature and ambient humidity. This study provides a novel strategy for the preparation of efficient and stable C-PSCs from the perspective of spatial structure regulation of bimetallic MOF-based composites.
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CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Wenmiao Zhao,Lishi Mo,Xiaoyuan Shi,Bo Liu,Guangmin Yang,Ting Deng
CoTe 2 as a potential electrode material for sodium-ion batteries (SIBs) suffers severe volume expansion and rapid capacity degradation. Herein, we propose an anionic chemistry regulation strategy to enhance the redox performance of CoTe 2 by Se substitution which creates more porosity inside the structure to accommodate the volume expansion. Physical characterizations and theoretical calculations have studied the structural and dynamical influence of Se/Te ratio on the overall performance. As a result, CoSe 1.33 Te 0.67 @C with a 〈1 1 1〉 preferential growth direction exhibited the most balanced performance, which delivered a high initial specific capacity of 795 mAh/g at 0.05 A/g, a high rate performance of 5 A/g and a capacity retention of 370 mAh/g after 400 cycles at 0.5 A/g. Accordingly, a full SIB was constructed with a Na 3 V 2 (PO 4 ) 3 cathode and a CoSe 0.67 Te 0.33 @C anode, delivering a maximum energy density of 197.2 Wh kg −1 . These results have proved that anionic chemistry regulation is quite efficient to synthesize metal tellurides with high redox activity and long life-span for SIB .
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CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Junpeng Jiang,Liwen Yan,Mengjia Song,Yifan Li,Anran Guo,Haiyan Du,Jiachen Liu
Thermal insulation and electromagnetic wave (EMW) absorption integrated materials with lightweight are highly desirable in hypersonic vehicles and military application, as they provide both aerodynamic heat resistance and EMW stealth capability. Herein, a C/SiC/SiBCN ceramic composite aerogel was developed using a novel strategy combining in situ chemical vapor deposition of SiC nanofibers with the polymer-derived ceramic (PDC) aerogel method. The microstructure, phase composition, thermal insulation, mechanical properties and EMW absorption performances of the composite aerogel were thoroughly investigated. The resulting C/SiC/SiBCN composite aerogel with three impregnation-pyrolysis cycles demonstrates improved mechanical properties, with the compressive strength increasing from 0.21 MPa to 0.48 MPa compared to pure SiBCN aerogel. Additionally, the composite aerogel shows a low thermal conductivity of 0.049 W/mK and a low density of 0.116 g/cm 3 . Moreover, the C/SiC/SiBCN composite aerogel exhibits outstanding EMW absorption properties, achieving a minimum reflection loss of −45.7 dB and an effective bandwidth of 5.3 GHz. Owing to the integration of EMW absorption and thermal insulation properties, the C/SiC/SiBCN composite aerogel offers promising potential for developing integrated microwave absorption and thermal insulation materials for high-speed vehicles.
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Materials Today Sustainability
·
2024
·
IF 7.1
Guilu Qin,Yifan Liu,Ruhumuriza Jonathan,Baoshan Wu,Xian Jian
TiO 2 semiconductor has the disadvantages of energy bandwidth, low photo-quantum efficiency, and electron-hole pair easy recombination, which makes TiO 2 semiconductor photocatalytic materials cannot be widely used efficiently. Here, a simple and low-cost method is used to prepare TiO 2 /C/Cu hybrid by in-situ carbon reduction by chemical vapor deposition. During high-temperature calcination, an amorphous carbon is formed on the surface of anatase TiO 2 , and CuO is reduced by in-situ carbon to obtain Cu. Partial Cu-doping into TiO 2 introduces defects, and in-situ Cu and C loads act as electron traps to reduce photogenerated electron/hole recombination. Compared with the original TiO 2 , the TiO 2 /C/Cu hybrids have a narrow band gap (2.77 eV) and abundant defect active sites and have excellent photocatalytic activity to improve the degradation of formaldehyde (HCHO) and methyl orange (MO) under visible light. In addition, after 4 cycles, the degradation of HCHO and MO still maintained excellent stability. This innovation has many potential applications in the future, including air purification and industry.
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Molecular Catalysis
·
2024
·
IF 3.9
Shengya Ge,Chenzhang Li,Peiyan Bi,Wei Hong
The operation of direct ethylene glycol fuel cells (DEGFCs) to generate electric energy from ethylene glycol rely on the effective electrocatalysts for the ethylene glycol oxidation reaction (EGOR). The fabrication of EGOR electrocatalysts with high activity, high durability and high resistance for corrosion, is essential important for the DEGFCs. Herein, we report a fabrication of Pd nanoparticles immobilized by the Ce-doped ZIF-67-derived carbon (Pd-CeO 2 /ZDC). The Pd nanoparticles are generated by the in-situ reduction reaction between the H 2 PdCl 4 and the Co nanoparticles formed during the ZIF-67 pyrolysis. Owe to the porous structure and N-doping inherited from the ZIF-67, the Pd and CeO 2 nanoparticles show a uniform distribution. Due to the enhanced EGOR electrooxidation kinetic promoted by the ZIF-67-derived support, the multiple-components and structure synergies, the resultant Pd-CeO 2 /ZDC catalyst affords a EGOR current density of 32.4 mA cm -2 , which is higher than the commercial Pd/C as well as the counterpart Pd/ZDC catalyst without CeO 2 . Furthermore, the Pd-CeO 2 /ZDC catalyst also present a better EGOR durability. This work provides a strategy for the design of EGOR catalyst with multiple-components and desired structure, which may inspire the new tactics for controllable design and synthesis of other electrocatalysts for various electrocatalysis.
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2024
·
IF 20.2
Hua Wang,Yunchuan Tu,Sijun Li,Yimin Jiang,Niandan Zhao,Wenbin Wang,Wei Shen,Ming Li,Rongxing He
Efficient electrocatalytic co-reduction of CO 2 and NO 3 − to urea involves simultaneous generation and stabilization of C- and N-coupling intermediates. Herein, we report positive feedback at the interfaces of an AuPd/SnO x catalyst that enables generation and stable co-adsorption of *CO and *NH 2 OH at low-potential, fostering efficient C-N coupling for urea formation. A combination of in-situ spectroscopic analyses and theoretical calculations show that *CO 2 captures electrons by bonding to the AuPd/SnO x interface, leading to positively charged Pd sites, which promote the NO 3 RR to give the key N-intermediate *NH 2 OH. The adsorbed *NH 2 OH provides electron feedback to the catalyst surface , which not only enhances the adsorption of CO 2 and promotes the conversion of *CO 2 to *CO to accelerate the CO 2 RR, but also enhances the adsorption strength of the catalyst for *CO. Owing to this positive feedback, the Faraday efficiency and yield of urea reached 21.3 % and 1280.5 μg∙h −1 ∙mg −1 at −0.2 V (versus the relative hydrogen electrode), surpassing the performance of most previously reported catalysts. This finding provides new insights into catalyst design for advancing C-N coupling systems.
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CATALYSIS TODAY
·
2024
·
IF 5.2
Wei Wang,Hong Zhao,Xikang Zhao,Junfeng Rong,Ning Liu,Peng Yu,Jingxin Xie,Genghuang Wu,Huan Li,Mudi Xin,Mingsheng Zong
Atomically well-dispersed platinum catalysts play a vital role in various chemical processes such as direct dehydrogenation of propane (PDH), due to their high performance originated from high atom utilization. However, these catalysts suffer from complex preparation methods, and preparing atomically dispersed Pt-based catalysts with feasible methods remains challenging. Herein, we report a convenient method to prepare efficient atomically dispersed Pt/C catalysts for PDH by sulfur doping into the carbon support by simple cyclohexane impregnation method. The prepared atomically well-dispersed catalysts possess strong interactions between Pt and carbon support, which led to improved exposure of active sites and higher propylene formation rate compared to that without sulfur doping. Sintering of the Pt species was also inhibited and stability was improved by 47%. Propylene selectivity also showed a positive correlation with the amount of sulfur doping. The propane conversion first increased and then decreased, which was due to the loss of sulfur during the reaction that caused the agglomeration of Pt and the evolution of structure. It was found that the maximum catalytic activity appeared with Pt clusters of ∼ 0.71 nm with an average Pt-Pt coordination number of 3.1 and Pt-Pt bond distance of 3.09 Å.
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APL Materials
·
2024
·Vol. 12
·期 4
·
IF 5.3
Lin Jia,Wang Shuai,Jin Hua,Cui Shuyuan,Wang Rongwen,Yang Yihang,Huang Guimei,Wang Jinhuo
The preparation of ceramic materials with complex porous structures through photopolymerization-based 3D printing requires the development of stable and printable slurries. In this study, zirconium acetylacetonate was incorporated into the thiol vinyl organosilicon prepolymer to create a photosensitive Si–Zr–O–C slurry. Regarding the natural bone structures and the Tyson polygon principle, a gradient pore structure was designed and then printed using a digital light processing 3D printer. After printing, the effects of sintering temperatures on the phase composition and structure of Si–Zr–O–C ceramics were systematically investigated. Subsequently, a comparative analysis of structure and properties was performed on sintered samples with different zirconium acetylacetonate contents. The results revealed that the sample containing 30 wt. % zirconium acetylacetonate exhibited a higher compressive strength of 9.70 ± 0.28 MPa and a lower room temperature thermal conductivity of 0.528 W m −1 K −1 . This study confirmed the significant potential of using 3D printing technology to prepare Si–Zr–O–C precursor ceramics with a porous structure.
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