ELECTROCHIMICA ACTA
·
2018
·
IF 5.116
Xiaozhen Chen,Ji Qi,Pan Wang,Chuang Li,Xiao Chen,Changhai Liang
Herein, PVA-Mo 2 C/Mo 2 N nanospheres with surface roughness are synthesized via a polyvinyl alcohol (PVA) involved approach and used for hydrogen evolution reaction (HER). The average crystallite size of the PVA protected nMo 2 CN nanospheres (6.1 nm) is one third of that of the PVA-Mo 2 C/Mo 2 N without PVA protection (17.9 nm). At 10 mA cm −2 current density, the as-synthesized PVA-Mo 2 C/Mo 2 N nanospheres with surface roughness exhibit HER overpotentials of 132 mV and 142 mV with corresponding Tafel slope of 51.8 mV dec −1 and 50.4 mV dec −1 in acid and alkaline medium, respectively. This high apparent activity can be attributed to the high intrinsic activity originated from the adjacent surface active sites of Mo 2 C and Mo 2 N as well as the large ECSA of PVA-Mo 2 C/Mo 2 N nanospheres with surface roughness.
研究领域:
材料科学
·
电化学
·
纳米催化
·
能源化学
·
表面科学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·Vol. 51
·期 6
·6968-6975
·
IF 5.1
Xinrong Yang,Deqin Chen,Guobin Zhu,Siyu Xiong,Xiaowei Zhu,Laijun Liu,Chunchun Li
The impact of configurational entropy on the microwave dielectric properties of LnNbO 4 fergusonite was investigated by designing a series of high-entropy counterparts, including (La, Nd, Sm, Ho, Yb, Y)NbO 4 (6RNO), (La, Nd, Sm, Eu, Ho, Yb, Y)NbO 4 (7RNO), (La, Nd, Sm, Eu, Gd, Ho, Yb, Y)NbO 4 (8RNO), and (La, Nd, Sm, Eu, Gd, Ho, Tm, Yb, Lu, Y)NbO 4 (10RNO). Simply prepared by the solid-state route, a pure phase with a monoclinic fergusonite structure of space group C /2 c was obtained. By comparing the microstructural evolution and lattice vibration modes, an analysis was conducted on the variations in microwave dielectric performances. It was confirmed that the permittivity ( ε r ) is primarily influenced by relative density, while the quality factor ( Q × f ) exhibits a strong correlation with packing fraction and lattice vibrations. The resonant frequency temperature coefficient (τ f ) is significantly associated with bond valence. The optimal microwave dielectric properties were achieved in 7RNO ceramics at a temperature of 1270 °C, resulting in a relative density of 95.43 %. The microwave dielectric properties were measured as ε r = 18.62, Q × f = 35200 GHz, τ f = −23.28 ppm/°C. The present study expands the application of entropy engineering to achieve ultrahigh configurational entropy in microwave dielectric ceramics . These findings demonstrate that optimizing the configuration entropy is an effective approach for manipulating the dielectric properties, thereby providing valuable insights for material component design.
研究领域:
材料科学
·
无机非金属材料
·
功能陶瓷
·
介电材料
·
固态化学
✓ 已验证
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2016
·
IF 4.803
M.Y. Gao,C. Yang,Q.B. Zhang,Y.W. Yu,Y.X. Hua,Y. Li,P. Dong
Porous Ni-Cu alloy films composed of nanosheets are directly fabricated on Cu substrate using a facile potentiostatic electrodeposition approach from a 1:2 choline chloride-ethylene glycol eutectic solvent (ethaline) containing nickel chloride and copper chloride. Electrochemical co-deposition of Ni-Cu alloy in ethaline is found to be thermodynamically favorable in comparison to conventional aqueous solutions. The deposition process occurs via an instantaneous nucleation and growth of nanoparticles at the initial stage and develops vertically to form nanoporous structures arrayed with nanosheets over deposition time . The as-prepared porous Ni-Cu alloy nanosheet arrays exhibit enhanced electrocatalytic activity for the hydrogen evolution reaction (HER) in alkaline media , which displays a small Tafel slope of 57.2 mV dec −1 with a low onset potential of −48 mV vs. RHE at an optimal condition. It requires small overpotentials of −128 and −150 mV to drive catalytic current densities of 10 and 20 mA cm −2 , respectively. This facile electrodeposition method performed in ethaline provides an efficient way to fabricate porous Ni-based alloy nanosheets directly on a current collector, which is a promising technology for the synthesis of earth-abundant HER electrocatalysts .
研究领域:
电催化
·
材料科学
·
能源化学
·
纳米材料
·
电化学
✓ 已验证
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2017
·
IF 4.798
Lvlv Ji,Lei Zhu,Jianying Wang,Zuofeng Chen
A self-supported copper sulfide (CuS) nanowire array (NWA) of hierarchical and porous structure has been developed on Cu foil via two consecutive liquid-solid reactions at room temperature. The composition, structure and morphology of the as-prepared CuS NWA samples have been systematically investigated by a series of techniques. When applied as cathode for the hydrogen evolution reaction (HER) in neutral solution, the optimized CuS NWA electrode exhibits excellent HER performance with high long-term stability. To achieve current densities of 10 and 100 mA cm −2 , it requires overpotentials of only ∼97 and ∼226 mV, respectively. The excellent catalytic performance of CuS NWA toward HER is attributable to the binder-free electrode construction strategy, the unique porous nanowire array structure, and the small solubility product ( K sp ) value of CuS that guarantees the high catalyst stability.
研究领域:
材料科学
·
电化学
·
纳米科技
·
能源化学
·
催化化学
✓ 已验证
DOI
高影响因子
APPLIED ORGANOMETALLIC CHEMISTRY
·
2019
·Vol. 33
·期 9
·e5082
·
IF 3.259
Dongmei He,Li Zeng,Guiqing Zhang,Qinggang Li,Wenjuan Guan,Zuoying Cao,Shengxi Wu
A new compound, α-aminophosphonate derivative containing pyridine ring (PPDE), was designed and synthesized as an extractant for the separation of nickel from metal impurities. Over 94.5% of Ni (II) extraction from sulfuric acid solution was achieved by using PPDE with an equilibrium pH of 4.02. Meanwhile, high separation coefficients of 23.8 for Ni to Co, 84.9 for Ni to Mn, 254.1 for Ni to Ca and 696.7 for Ni to Mg, respectively, were obtained. It was noted that PPDE exhibited an excellent regenerability, and the extraction of Ni with the recycled organic phase ranged from 92.5% to 93.9% during six circulations. The extracted nickel complex was determined as [Ni (PPDE) 2 (DNNSA − ) 2 (H 2 O) 4 ], which was supported by the data obtained from Fourier transform-infrared, UV–Vis and electrospray ionization-mass spectrometry spectra.
研究领域:
无机化学
·
湿法冶金
·
分离科学
·
配位化学
·
环境化学
·
资源回收
✓ 已验证
DOI
高影响因子
JOURNAL OF RARE EARTHS
·
2017
·Vol. 36
·期 3
·304-310
·
IF 2.429
Shengting Kuang,Zhifeng Zhang,Yanling Li,Haiqin Wei,Wuping Liao
The extraction and separation of heavy rare earths (REs) using newly synthesized α-aminophosphonic acid extractant 2-ethylhexyl-3-(2-ethylhexylamino)pentan-3-yl phosphonic acid (HEHAPP, H A ) in n-heptane were investigated from chloride medium. The extraction stoichiometries of lanthanum , gadolinium , yttrium and lutetium are determined to be RE A 3 by the slope analysis method. The favorable separation factors of adjacent heavy REs(Ⅲ), i.e. β Y/Ho , β Er/Y , β Tm/Er , β Yb/Tm and β Lu/Yb , are determined to be 1.87, 1.36, 3.21, 3.22 and 1.93, respectively, when extracted from a binary system at proper condition. The loading capacities of H A for Ho, Er, Yb and Lu increase in the order Ho < Er < Yb < Lu with the values being 0.201, 0.205, 0.216 and 0.229 mol/L, respectively. So H A would be a potential extractant for the separation of heavy REs(Ⅲ). Among inorganic acids such as H 2 SO 4 , HNO 3 and HCl, HCl is tested to be the most effective stripping agent.
研究领域:
湿法冶金
·
稀土化学
·
分离科学与技术
·
无机化学
·
萃取化学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2016
·Vol. 42
·期 6
·7767-7773
·
IF 2.758
Shuangbing Li,Jixiao Wang,Song Zhao,Wei Cai,Zhi Wang,Shichang Wang
The unmodified and 3-(trimethoxysilyl) propyl methacrylate (TPM) modified silica nanoparticles were synthesized via the modified Stöber method. The structure and chemical composition of silica nanoparticles were determined by scanning electron microscope (SEM), X-ray diffraction (XRD) characterization, Fourier Transform Infrared Spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The results demonstrate that silica nanoparticles with the diameter of 90 nm and amorphous state are successfully modified by TPM. The rheological test results demonstrated that surface modification of nanoparticles and medium exerted great influence on the rheological properties of silica particle suspension. Under high shear rate of about 250 s −1 , the viscosity of suspension comprising unmodified silica nanoparticles and deionized water , TPM-modified silica nanoparticles and deionized water, TPM-modified silica nanoparticles and polyethylene glycol , is about 0.4 Pa.s, 0.1 Pa.s and 30 Pa.s, respectively. The results are significant for preparing homogenous and stable silica nanoparticle suspension, and meaningful for ceramic processing .
研究领域:
材料科学
·
纳米技术
·
陶瓷加工
·
胶体化学
·
高分子材料
✓ 已验证
DOI
高影响因子
Advanced Materials Interfaces
·
2018
·Vol. 5
·期 15
·1800515
·
IF 4.834
Lingxia Zheng,Wangwang Hu,Xuwei Shu,Huajun Zheng,Xiaosheng Fang
Cobalt phosphides based materials are considered as promising electrocatalysts for the hydrogen evolution reaction (HER). The catalytic performance can be further enhanced by improving the intrinsic catalytic activity, exposing more active sites and coupling with conductive support. Herein, a novel electrocatalyst based on nitrogen doped reduced graphene oxides decorates with uniformly distributed CoP x nanoparticles with a suitable P/Co ratio ( x = 1.7) via a facile and mild condition. The optimized composite (CoP x /N-rGO) exhibits superior electrocatalytic HER activities with a low overpotential of 104 mV (at 10 mA cm −2 ), a small Tafel slope of 65 mV dec −1 , and long-term stability in the alkaline media, comparable to the performance of other HER electrocatalysts. The remarkable HER performance can be ascribed to the good electrical conductivity of rGO and extra active sites created by nitrogen doping. In addition, the ultrafine nanostructure (average particle size ≈4 nm) and well-dispersed CoP x nanoparticles also help expose more active sites for electrocatalytic reactions, largely hindering the agglomeration and exfoliation. This work provides a versatile route on the design of multifunctional composite materials for renewable energy research with low cost and high activity.
研究领域:
材料科学
·
电化学
·
纳米科技
·
能源化学
·
催化化学
✓ 已验证
DOI
高影响因子
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2022
·
IF 4.598
Mingyuan Chen,Yaxin Lv,Peilin Wu,Liuyan Dong,Xingquan He,Lili Cui
To obtain highly active electrocatalyst for the whole electrochemical water splitting is of importance to generate hydrogen. Co(OH) 2 is used as electrocatalyst towards OER, however, the performance can be improved further. Usually, to construct the interface and adjust the electronic environment of electrocatalysts are regarded as powerful ways to improve the activity. Herein, CeO 2 -Co(OH) 2 sheets supported on copper foam (CF) are fabricated by electrodeposition method. The morphology and the electron structure of metals are adjusted by changing the molar ratio of Co to Ce, thus, resulting in different electrocatalytic activity. The optimal hybrids of CeO 2 -Co(OH) 2 exhibits lower overpotentials of 188, 269 mV to reach 10 mA cm −2 towards HER and OER, respectively, and good stability. Notably, it is found that the electroactivity is extremely superior to that of bare CF as well as the counterparts in the literature. Also, we try to employ M(OH) 2 (M = Fe, Ni) to substitute Co(OH) 2 to investigate the effect of species of hydroxides on the electron interaction between CeO 2 and hydroxides, the XPS results indicate that Ce and Co shows stronger electron interaction compared to other two control hydroxides. As electrocatalysts for alkaline full water splitting, CeO 2 -Co(OH) 2 requires a cell voltage of 1.62 V to drive 10 mA cm −2 . Experimental results prove the advantages of the electron engineering and morphology control.
研究领域:
材料科学
·
电化学
·
能源化学
·
纳米材料
·
催化化学
✓ 已验证
DOI
高影响因子
CHEMOSPHERE
·
2018
·
IF 4.427
Xianqiang Yin,Yanji Jiang,Yuehui Tan,Xiangmin Meng,Huimin Sun,Nong Wang
The ability to predict the transport of heavy metal ions in porous media with different surface characteristics is crucial to protect groundwater quality and public health. In this study, the effects of graphene oxide (GO) on co-transport and remobilization of Pb 2+ and Cd 2+ in humic acid (HA), smectite , kaolinite , and ferrihydrite-coated sand media were evaluated via laboratory packed-column experiments. Scanning electron microscope and energy dispersive X-ray analysis showed that the surface morphology of the coated sands was quite different and that ∼56.7–89.9% of the surface was covered by the coating and the major elemental components were C, O, Si, Al, and Fe. GO exhibited high mobility in HA, kaolinite , and smectite-coated sand, but showed high retention in ferrihydrite-coated sand. While GO reduced the transport of Pb 2+ and Cd 2+ , both metal ions also reduced the mobility of GO in coated-sand columns. Elution experiments revealed that GO led to the remobilization and release of the previously sorbed Pb 2+ and Cd 2+ from the coated sand. However, GO could not release Pb 2+ and Cd 2+ from smectite-coated sand columns, probably because smectite has stronger adsorption affinity to the heavy metals than GO. Derjaguin-Landau-Verwey-Overbeek calculations were employed and explained the GO transport behavior in the columns well. Furthermore, the advection-dispersion-reaction equation simulated the cotransport of Pb 2+ and Cd 2+ with GO in the coated sand well. These results are expected to provide insight into the potential impact of coexisting nanomaterials with contaminants in vulnerable soil and groundwater systems.
研究领域:
环境地球化学
·
土壤学
·
水文地质学
·
纳米毒理学
·
环境污染与修复
✓ 已验证
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2015
·
IF 4.504
K. Huang,K. Bi,J.C. Xu,C. Liang,S. Lin,W.J. Wang,T.Z. Yang,Y.X. Du,R. Zhang,H.J. Yang,D.Y. Fan,Y.G. Wang,M. Lei
Novel nanocomposites of spherical graphite-carbon encased tungsten carbide (GC-WC) are synthesized by solid state reaction with melamine and WO 3 as precursors under N 2 atmosphere. The diameters of the GC-WC composites range from 50 to 200 nm and the WC nanoparticles inside with an average size of ca. 15 nm distribute uniformly. The characterization results indicate that the GC-WC is composed of few layers of graphite carbon and WC nanoparticles with high crystallization and purity. Moreover, the electrocatalytic performance of GC-WC for the oxygen reduction reaction (ORR) in alkaline medium is further investigated by cyclic voltammetry (CV), rotating disk electrode (RDE) and chronoamperometry test with or without 3 M methanol. The results show that GC-WC has a considerable performance for ORR in the view of activity, stability and methanol tolerance, which may further used as proper supports for noble-metal based ORR catalysts in alkaline fuel cell . The synergetic interaction between the carbide nanoparticles and graphite carbon, which means that the surface graphite carbon layers are activated by WC nanoparticles for ORR and in turn protect inner WC from highly oxidizing environments has also been verified.
研究领域:
材料科学
·
纳米科技
·
电化学
·
能源材料
·
催化化学
✓ 已验证
DOI
高影响因子
Materials Today Energy
·
2022
·
IF 9.257
Jing Fu,Mingcong Yang,Rui Wang,Sang Cheng,Xiaoyan Huang,Shaojie Wang,Junluo Li,Manxi Li,Jinliang He,Qi Li
The electrostatic energy storage performance of polymer dielectrics at high temperature and high electric field can be significantly improved by the incorporation of wide-bandgap, nano-sized particles. It is traditionally believed that the embedded nanoparticles can scatter the hot charges and lead to charge trapping in the interfacial region , which suppress the conduction loss and promote the energy storage performance. In this work, the nano-sized γ-Al 2 O 3 with cubic defect spinel structure and nano-sized α-Al 2 O 3 with a wider bandgap are introduced into a heat-resistant dielectric polymer, respectively, to form two different nanocomposites . The field-dependent energy storage performance, electrical conductivity , and breakdown strength of the polymer nanocomposites at high temperatures, as well as the thermally stimulated depolarization current , are investigated. The results indicate that the intrinsic deep traps introduced by γ-Al 2 O 3 with cubic defect spinel structure are a more critical factor in improving the energy storage performance of the polymer-based composites. We anticipate that our findings reported in this work may help to better guide the selection of nanofillers for high-temperature dielectric polymer nanocomposites.
研究领域:
材料科学
·
介电物理
·
高分子物理
·
能源材料
·
电气工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）