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Bimetallic Single‑Atom Catalysts for Water Splitting

Nano-Micro Letters 2025年第1期17卷 1-45页

作者： Megha A.Deshmukh Aristides Bakandritsos Radek Zbořil nanotechnology Centre Centre for Energy and Environmental TechnologiesVŠB–Technical University of Ostrava17.listopadu 2172/1570800 Ostrava‑PorubaCzech Republic Regional Centre of advanced Technologies and materials Czech Advanced Technology and Research Institute(CATRIN)Palacky University OlomoucŠlechtitelů241/2778371 Olomouc–HoliceCzech Republic

Green hydrogen from water splitting has emerged as a critical energy vector with the potential to spearhead the global transition to a fossil fuel-independent *** field of catalysis has been revolutionized by single-atom catalysts(SACs),which exhibit unique and intricate interactions between atomically dispersed metal atoms and their ***,bimetallic SACs(bimSACs)have garnered significant attention for leveraging the synergistic functions of two metal ions coordinated on appropriately designed *** offer an avenue for rich metal–metal and metal–support cooperativity,potentially addressing current limitations of SACs in effectively furnishing transformations which involve synchronous proton–electron exchanges,substrate activation with reversible redox cycles,simultaneous multi-electron transfer,regulation of spin states,tuning of electronic properties,and cyclic transition states with low activation *** review aims to encapsulate the growing advancements in bimSACs,with an emphasis on their pivotal role in hydrogen generation via water *** subsequently delve into advanced experimental methodologies for the elaborate characterization of SACs,elucidate their electronic properties,and discuss their local coordination ***,we present comprehensive discussion on the deployment of bimSACs in both hydrogen evolution reaction and oxygen evolution reaction,the two half-reactions of the water electrolysis process.

关键词： Single-atom catalysts Single-atom dimers Hydrogen evolution Oxygen evolution Water splitting

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Mechanical properties of the A356 aluminum alloy modified with La/Ce

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Journal of Rare Earths 2013年第8期31卷 811-816页

作者： E. Aguirre-De la Torre R. Pérez-Bustamante J. Camarillo-Cisneros C.D. Gómez-Esparza H.M. Medrano-Prieto R. Martínez-Sánchez advanced materials Research Center (CIMAV) National Laboratory of Nanotechnology

The research of rare earths for the synthesis of materials with improved mechanical performance is of great interest when they are considered for potential applications in the automotive industry. In this regard, the effect on the mechanical properties and microstmcture of the automotive A356 aluminum alloy reinforced with 0.2 （wt.%） AI-6Ce-3La （ACL） was investigated. The ACL was added to the melted A356 alloy in the as-received condition and processed by mechanical milling. In the second route, the effect of the ACL processed by mechanical milling and powder metallurgy techniques was investigated, and compared with the results ob- tained from the A356 alloy strengthened with ACL in the as-received condition. Microstmctural properties were evaluated by means of X-ray diffraction in order to observe the solubility of Ce/La in the A1 matrix. In addition, electron microscopy was employed in or- der to investigate the effect of milling time on the size and morphology of La/Ce phase under milling process. Mechanical properties of the A356 alloy modified with ACL were measured by hardness and tensile test. For comparison unmodified specimens of the A356 were characterized according to the previous procedure. The microstructural and mechanical characterization was carried out in specimens alter solution and artificial aging. Observations in scanning electron microscopy indicated a homogeneous dispersion of La/Ce phases by using both routes; however, mechanical results, in the modified A356 alloy with the ACL in the as-received condi- tion, showed an improvement in the mechanical performance of the A356 alloy over that reinforced with the ACL mechanically milled.

关键词： A356 rare earths mechanical milling mechanical properties

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Improvement of the off-state breakdown voltage with field plate and low-density drain in AlGaN/GaN high-electron mobility transistors

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Chinese Physics B 2015年第3期24卷 332-335页

作者：张鹏赵胜雷侯斌王冲郑雪峰马晓华张进成郝跃 Key laboratory of Wide Band-Gap Semiconductor materials and Devices School of Advanced Materials and NanotechnologyXidian University

We present an AlGaN/GaN high-electron mobility transistor（HEMT） device with both field plate（FP） and lowdensity drain（LDD）. The LDD is realized by the injection of negatively charged fluorine（F-） ions under low power in the space between the gate and the drain electrodes. With a small-size FP and a LDD length equal to only 31% of the gate-drain spacing, the device effectively modifies the electric field distribution and achieves a breakdown voltage enhancement up to two times when compared with a device with only FP.

关键词： GaN high-electron mobility transistors fluorine electric field

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Defects‑Rich Heterostructures Trigger Strong Polarization Coupling in Sulfides/Carbon Composites with Robust Electromagnetic Wave Absorption

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Nano-Micro Letters 2025年第1期17卷 528-547页

作者： Jiaolong Liu Siyu Zhang Dan Qu Xuejiao Zhou Moxuan Yin Chenxuan Wang Xuelin Zhang Sichen Li Peijun Zhang Yuqi Zhou Kai Tao Mengyang Li Bing Wei Hongjing Wu Mengyang Li Bing Wei Hongjing Wu School of Physics Xidian UniversityXi’an 710071People’s Republic of China School of advanced materials and nanotechnology State Key Discipline Laboratory of Wide Band Gap Semiconductor TechnologyXidian UniversityXi’an 710071People’s Republic of China School of Microelectronics Xidian UniversityXi’an 710071People’s Republic of China School of Telecommunication Engineering Xidian UniversityXi’an 710071People’s Republic of China MOE Key laboratory of Material Physics and Chemistry Under Extraordinary School of Physical Science and TechnologyNorthwestern Polytechnical UniversityXi’an 710072People’s Republic of China The Ministry of Education Key laboratory of Micro and Nano Systems forAerospace School of Mechanical EngineeringNorthwestern PolytechnicalUniversityXi’an 710072People’s Republic of China

Defects-rich heterointerfaces integrated with adjustable crystalline phases and atom vacancies,as well as veiled dielectric-responsive character,are instrumental in electromagnetic *** methods,however,constrain their delicate ***,an innovative alternative is proposed:carrageenan-assistant cations-regulated(CACR)strategy,which induces a series of sulfides nanoparticles rooted in situ on the surface of carbon *** unique configuration originates from strategic vacancy formation energy of sulfides and strong sulfides-carbon support interaction,benefiting the delicate construction of defects-rich heterostructures in M_(x)S_(y)/carbon composites(M-CAs).Impressively,these generated sulfur vacancies are firstly found to strengthen electron accumulation/consumption ability at heterointerfaces and,simultaneously,induct local asymmetry of electronic structure to evoke large dipole moment,ultimately leading to polarization coupling,i.e.,defect-type interfacial ***“Janus effect”(Janus effect means versatility,as in the Greek two-headed Janus)of interfacial sulfur vacancies is intuitively confirmed by both theoretical and experimental investigations for the first ***,the sulfur vacancies-rich heterostructured Co/Ni-CAs displays broad absorption bandwidth of 6.76 GHz at only 1.8 mm,compared to sulfur vacancies-free CAs without any dielectric *** defects-rich heterostructures,this one-pot CACR strategy may steer the design and development of advanced nanomaterials,boosting functionality across diverse application domains beyond electromagnetic response.

关键词： Defects-rich heterointerfaces Sulfides Polarization coupling Electromagnetic wave absorption

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Effect of alkaline metal ions on the photoluminescence properties of Eu^(3+)-doped Ca_3Al_2O_6 phosphors

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Journal of Rare Earths 2016年第12期34卷 1193-1198页

作者： Kyeongsoon Park Joon Woo Pi Deshmukh Abdul Hakeem Faculty of nanotechnology and advanced materials Engineering Sejong University

Ca3–xAl2O6：x Eu^3＋（0.02≤x≤0.10） and Ca（2.92）Al2O6：0.04Eu^3＋,0.04M^＋（M^＋=Li^＋, Na^＋, and K^＋） phosphors were prepared by sol-gel method and their photoluminescence properties were investigated. The crystal structure of the annealed Ca3–xAl2O6：x Eu^3＋ and Ca（2.92）Al2O6：0.04Eu^3＋,0.04M^＋ phosphors was analyzed with X-ray diffraction（XRD）. The size and morphological characteristics of the annealed phosphors were investigated with a field emission scanning electron microscope（FE-SEM）. The photoluminescence properties were evaluated with a spectrofluorometer. The phosphors were effectively excited by the light of 396 nm and showed intense red emission at 616 nm, which originated from the 5D0→7F2 transition of Eu^3＋. Among the prepared phosphors, the Ca（2.96）Al2O6：0.04Eu^3＋ phosphor showed the strongest emission intensity and the highest color purity. The addition of alkaline metal ions（Li^＋, Na^＋, and K^＋） to Ca（2.96）Al2O6：0.04Eu^3＋ phosphor degraded the emission intensity and color purity.

关键词： phosphor photoluminescence emission sol-gel method Eu3+ rare earths

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TiP_2O_7-coated LiNi_(0.8)Co_(0.15)Al_(0.05)O_2 cathode materials with improved thermal stability and superior cycle life

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Journal of Energy Chemistry 2019年第1期28卷 151-159页

作者： Guan Wu Yingke Zhou The State Key laboratory of Refractories and Metallurgy Institute of Advanced Materials and Nanotechnology College of Materials and Metallurgy Wuhan University of Science and Technology

The co-precipitation derived LiNi_(0.8)Co_(0.15)Al_(0.05)O_2 cathode material was modified by a coating layer of TiP_2O_7 through an ethanol-based process. The TiP_2O_7-coated LiNi_(0.8)Co_(0.15)Al_(0.05)O_2 is characterized by Xray diffraction analysis, scanning electron microscopy and transmission electron microscopy to investigate the microstructure and morphology. The differential scanning calorimetry was employed to confirm the improved thermal stability. The electrochemical properties were evaluated by the constant-current charge/discharge tests. The TiP_2O_7 coating layer is effectively suppressing the structural degradation and ameliorating the surface status of LiNi_(0.8)Co_(0.15)Al_(0.05)O_2 particles, and the intrinsic rhombohedral layered structure of TiP_2O_7-coated LiNi_(0.8)Co_(0.15)Al_(0.05)O_2 was well maintained during the long-term cycling process, while the surface structure of pristine LiNi_(0.8)Co_(0.15)Al_(0.05)O_2 was degraded from rhombohedral R3 m layered structure to cubic rock-salt structure. The charged state Ni^(4+) ions will easily transform into Ni^(2+) when the electrolytes oxidized at the interface of cathode/electrolytes and formed the cubic rock-salt NiO type structure, and the cubic rock-salt structure without electrochemical activity on the surface of LiNi_(0.8)Co_(0.15)Al_(0.05)O_2 particles will finally accelerate capacity fading. The thermal stability and cyclic performances of the LiNi_(0.8)Co_(0.15)Al_(0.05)O_2 electrode were remarkably improved by TiP_2O_7 coating, the total amount of heat release corresponding to the intensity of thermal runaway were 1075.5 and 964.6 J/g for pristine LiNi_(0.8)Co_(0.15)Al_(0.05)O_2 and TiP_2O_7-coated LiNi_(0.8)Co_(0.15)Al_(0.05)O_2 respectively, the pouch shaped full cells that employed TiP 2 O7-coated LiNi_(0.8)Co_(0.15)Al_(0.05)O_2 as cathode were able to perform more than 2200 cycles at 25 ℃ and more than 1000 cycles at 45 ℃ before the capacity retention fading to 80%.

关键词： LiNi0.8Co0.15Al0.05O2 Coating Thermal stability Cyclic performances Lithium-ion batteries

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Fabrication of a monolithic 4H-SiC junction barrier schottky diode with the capability of high current

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Science China(Technological Sciences) 2015年第8期58卷 1369-1374页

作者： SONG QingWen YUAN Hao HAN Chao ZHANG YuMing TANG XiaoYan ZHANG YiMeng GUO Hui ZHANG YiMen JIA RenXu WANG YueHu School of advanced materials and nanotechnology Xidian University Key laboratory of Wide Band Gap Semiconductor materials and Devices Xidian University

There is a great interest in monolithic 4H-SiC Junction Barrier Schottky （JBS） diodes with the capability of a high forward current for industrial power applications. In this paper, we report large-area monolithic 4H-SiC JBS diodes fabricated on a 10 μm 4H-SiC epitaxial layer doped to 6×1015 cm-3. JBS diodes with an active area of 30 mm2 had a forward current of up to 330 A at a forward voltage of 5 V, which corresponds to a current density of 1100 A/cm2. A near ideal breakdown voltage of 1.6 kV was also achieved for a reverse current of up to 100 gA through the use of an optimum multiple floating guard rings （MFGR） termination, which is about 87.2% of the theoretical value. The differential specific-on resistance （RSP-ON） was meas- ured to be 3.3 mΩcm2, leading to a FOM （VB2/RSP-ON） value of 0.78 GW/cm2, which is very close to the theoretical limit of the tradeoff between the specific-on resistance and breakdown voltage for 4H-SiC unipolar devices.

关键词： 4H-SiC JBS current capability breakdown voltage

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Preparation and infrared emissivities of alkali metal doped ZnO powders

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Journal of Central South University 2014年第9期21卷 3449-3455页

作者：李会会黄云霞李智敏姚银华张淑敏 School of advanced materials and nanotechnology Xidian University

Alkali metal(Li, Na, K) doped ZnO powders were synthesized by solid-state reaction at different calcination temperatures and holding time. Effects of holding time and K sources on the infrared emissivity of ZnO were investigated. The structure and surface morphologies of samples were characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM). The UV-Vis absorption and infrared emissivities were investigated by a UV-Vis spectrophotometer and an infrared emissometer, respectively. XRD patterns confirm the wurtzite structure of the as prepared samples with single phase. Smooth grain surfaces are detected in all doped ZnO samples, while ZnO:Li and ZnO:Na present the aggregation of grains. The redshifts in the optical band-gap are observed in K-, Na-, and Li-doped ZnO with the values 3.150, 3.144, and 3.142 eV. Due to better crystalline quality, ZnO:K shows a lower emissivity than others. The emissivity of K-doped ZnO decreases to the minimum value(0.804), at 1200 °C and holding 2 h. Compared with KNO3 as K source, K2CO3 doped ZnO has lower emissivities.

关键词： infrared emissivity alkali metal crystalline quality optical band-gap ZnO powders

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Development of anti-corrosive coating on AZ31 Mg alloy modified by MOF/LDH/PEO hybrids

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Journal of Magnesium and Alloys 2024年第2期12卷 586-607页

作者： Muhammad Ali Khan Ananda Repycha Safira Mohammad Aadil Mosab Kaseem Corrosion and Electrochemistry laboratory Department of Nanotechnology and Advanced Materials EngineeringSejong UniversitySeoul 05006Republic of Korea

The self-assembly of hybrid inorganic-organic materials on stationary platforms plays a critical role in improving their structural stability and wide *** this work,a novel two-step hydrothermal approach is proposed for synthesizing stable and advanced hybrid coatings on metal-oxide platforms through the surface modification of layered double hydroxide(LDH)films using novel metal-organic frameworks(MOFs).Initially,Mg-Al LDH nanocontainers,grown on a magnesium oxide layer produced through plasma electrolytic oxidation(PEO)of AZ31 Mg alloy substrate,were intercalated with cobalt via an oxidation route,providing the metallic coordination center for the MOF *** the subsequent step,a pioneering technique is introduced,utilizing tryptophan as the organic linker for the first time at a pH of *** self-assembly of cobalt-tryptophan complex,driven by the strong bonding between electrophilic sites of monomers and nucleophilic sites,facilitated the formation of a MOF network having a cloud-like structure on the surface of MgAl LDH's *** resulting MOF-LDH encapsulation containers demonstrate exceptional electrochemical stability when exposed to a 3.5 wt.%NaCl solution,surpassing the performance of PEO and pure LDH *** enhanced stability is attributed to the development of a dense top layer and a stable composition within the self-assembled MOF,effectively sealing flaws and preventing the infiltration of corrosive ions into the underlying metallic *** formation mechanism of MOFs on LDH galleries is investigated using density functional theory calculations.

关键词： Mg alloy Layered double hydroxide Metal-organic frameworks Corrosion DFT

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Contact-Size-Dependent Cutoff Frequency of Bottom-Contact Organic Thin Film Transistors

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Chinese Physics Letters 2015年第10期32卷 110-112页

作者：孙静王宏王湛吴士伟马晓华 School of advanced materials and nanotechnology Key Laboratory of Wide Band-Gap Semiconductor TechnologyXidian University

The contact-size-dependent characteristic of cutoff frequency fT in bottom-contact organic thin film transistors （OTFTs） is studied. The effects of electrode thickness, field-effect mobility, channel length and gate-source voltage on the contact length （source and drain electrodes＇ length） related contact resistance of bottom-contact OTFTs are performed with a modified transmission line model. It is found that the contact resistance increases dramatically when the contact length is scaled down to 20O nm. With the help of the contact length related contact resistance, contact-size-dependent fT Of bottom-contact OTFTs is studied and it is found that fr increases with the decrease of the contact length in bottom-contact OTFTs.

关键词： Contact-Size-Dependent Cutoff Frequency of Bottom-Contact Organic Thin Film Transistors length

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