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871.
Dr. Linzhou Zhuang Dr. Yi Jia Hongli Liu Zhiheng Li Dr. Mengran Li Dr. Longzhou Zhang Dr. Xin Wang Prof. Dongjiang Yang Prof. Zhonghua Zhu Prof. Xiangdong Yao 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(34):14772-14778
The oxygen vacancies of defective iron–cobalt oxide (FeCoOx-Vo) nanosheets are modified by the homogeneously distributed sulfur (S) atoms. S atoms can not only effectively stabilize oxygen vacancies (Vo), but also form the Co−S coordination with Co active site in the Vo, which can modulate the electronic structure of the active site, enabling FeCoOx-Vo-S to exhibit much superior OER activity. FeCoOx-Vo-S exhibits a mass activity of 2440.0 A g−1 at 1.5 V vs. RHE in 1.0 m KOH, 25.4 times higher than that of RuO2. The Tafel slope is as low as 21.0 mV dec−1, indicative of its excellent charge transfer rate. When FeCoOx-Vo-S (anode catalyst) is paired with the defective CoP3/Ni2P (cathode catalyst) for overall water splitting, current densities of as high as 249.0 mA cm−2 and 406.0 mA cm−2 at a cell voltage of 2.0 V and 2.3 V, respectively, can be achieved. 相似文献
872.
Jiaxi Zhang Longhai Zhang Li Du Huolin L. Xin John B. Goodenough Zhiming Cui 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(40):17641-17646
A group of newly reported antiperovskite nitrides CuxIn1−xNNi3 (0≤x≤1) with tunable composition are employed as electrocatalysts for the hydrogen evolution reaction (HER). Cu0.4In0.6NNi3 shows the highest intrinsic performance among all developed catalysts with an overpotential of merely 42 mV at 10 mA cmgeo−2. Stability tests at a high current density of 100 mA cmgeo−2 show its super-stable performance with only 7 mV increase in overpotential after more than 60 hours of measurement, surpassing commercial Pt/C (increase of 170 mV). By partial substitution, the derived antiperovskite nitride achieves a smaller kinetic barrier of water dissociation compared to the unsubstituted InNNi3 and CuNNi3, revealed by first-principle calculations. It is found that the partially substituted CuxIn1−xNNi3 possesses a thermal neutral and desirable Gibbs free energy of hydrogen for HER, ascribed to the tailoring of the energy of d-band center arose by the A-site (A=Cu or In) substitution and a resulting optimization of adsorbate interactions. 相似文献
873.
Wan-Feng Zhang Xiao-Ping Xia Takahashi Eiichi Li Li Qing Yang Yan-Qiang Zhang Ya-Nan Yang Ming-Liang Liu Chunkit Lai 《Surface and interface analysis : SIA》2020,52(5):224-233
Secondary ion mass spectrometry (SIMS) has a wide range of applications in Earth Science research, thanks to its high precision and sensitivity, and its capacity in direct insitu micromeasurement. The technique is operated in ultra-high vacuum (UHV) conditions, especially for the measurement of volatiles such as hydrogen, or the water content in nominally anhydrous minerals (NAMs). To minimize the water background and obtain accurate and precise water contents in NAMs (eg, olivine) critical parameters such as presputtering time, field aperture (FA), dynamic transfer on/off, and primary beam current intensity were investigated for a CAMECA IMS 1280-HR system. When the chamber vacuum reaches approximately 2 × 10−9 mbar, we set the DTOS OFF, raster size to 50 μm and primary beam current to 5 nA, and used 2000 μm FA and 170-second presputtering time. Consequently, an approximately 1.2 ppmw water background and 3.6 ppmw limit of detection (LOD) were yielded, from analyzing the San Carlos olivine. Meanwhile, the water content and homogeneity of a range of olivine minerals were characterized for potential use as reference materials for SIMS water content measurement. Olivine water content calibration curve was also established by comparing the Fourier transform infrared (FTIR) results with the SIMS-measured 16O1H−/16O− ratios. Accuracy and precision of water content measurement were estimated to be better than approximately 10% in this study. 相似文献
874.
Solène Béchu Muriel Bouttemy Jackie Vigneron Daniel Lincot Jean-François Guillemoles Arnaud Etcheberry 《Surface and interface analysis : SIA》2020,52(12):975-979
Cu(In,Ga)Se2 absorbers were immerged in deionized water for different times, and specific chemical evolutions were monitored thanks to X-ray photoemission spectroscopy. Cu(In,Ga)Se2 related dissolution products were studied in water through induced coupled plasma optical emission spectroscopy. From those analyses, specific surface network disorganization was observed, with Cu migration towards the surface, leading to different kinetics of oxidation and dissolution for each element that could be quantified. 相似文献
875.
Ultralight flexible polymers enable promising application in many fields but are often hindered by low reusability with fatigue failure, weak mechanical stability and low temperature resistance. Here, superelastic polyimide nanofiber aerogels (PNFAs) with high hydrophobicity have been prepared by utilizing the polyamic acid (PAA) nanofibers to construct a continuous and isotropic fibrous architecture. “Fiber-bonding” effect is designed to endow the PNFAs with the structure-derived superelasticity. The results demonstrate that the PNFAs possess ultralight densities (9.7–19.1 mg cm−3), excellent absorption capacity (58 times for n-hexane), broad working-temperature range, high resilience after 1000 fatigue cycles at 60% strain, and outstanding thermal insulation performance. Analysis of 50 absorption-harvesting cycle tests reveals that these highly hydrophobic PNFAs possess an ultrahigh reusability. The compressed PNFAs return to their original shape after they are distilled to recover the absorbed pollutants. These PNFAs with high absorption capacity and robust mechanical stability are promising to be applied in a variety of industrial and environmental applications. 相似文献
876.
采用电喷雾离子化沉积技术, 在氟掺杂锡氧化物(FTO)衬底上制备了均匀的无定形铁镍双金属氢氧化物薄膜. 与浸泡法制备的薄膜相比, 该薄膜具有更高的纯度、 更大的比表面积和较高的电催化水氧化性能, 在10 mA/cm 2时的过电位为290 mV, 并在催化反应中表现出良好的稳定性, 为可控合成高催化活性的过渡金属氢氧化物薄膜提供了一种新方法. 相似文献
877.
Víctor Manuel Castor-Villegas José Manuel Guevara-Vela Wilmer E. Vallejo Narváez Ángel Martín Pendás Tomás Rocha-Rinza Alberto Fernández-Alarcón 《Journal of computational chemistry》2020,41(26):2266-2277
Hydrogen bonds (HB) are arguably the most important noncovalent interactions in chemistry. We study herein how differences in connectivity alter the strength of HBs within water clusters of different sizes. We used for this purpose the interacting quantum atoms energy partition, which allows for the quantification of HB formation energies within a molecular cluster. We could expand our previously reported hierarchy of HB strength in these systems (Phys. Chem. Chem. Phys., 2016, 18 , 19557) to include tetracoordinated monomers. Surprisingly, the HBs between tetracoordinated water molecules are not the strongest HBs despite the widespread occurrence of these motifs (e.g., in ice Ih). The strongest HBs within H2O clusters involve tricoordinated monomers. Nonetheless, HB tetracoordination is preferred in large water clusters because (a) it reduces HB anticooperativity associated with double HB donors and acceptors and (b) it results in a larger number of favorable interactions in the system. Finally, we also discuss (a) the importance of exchange-correlation to discriminate among the different examined types of HBs within H2O clusters, (b) the use of the above-mentioned scale to quickly assess the relative stability of different isomers of a given water cluster, and (c) how the findings of this research can be exploited to indagate about the formation of polymorphs in crystallography. Overall, we expect that this investigation will provide valuable insights into the subtle interplay of tri- and tetracoordination in HB donors and acceptors as well as the ensuing interaction energies within H2O clusters. 相似文献
878.
Shuman Li Alireza Azizi Steven R. Kirk Samantha Jenkins 《International journal of quantum chemistry》2020,120(19):e26361
We seek to explain why the hydrogen bond possesses unusual strength in small water clusters that account for many of the complex behaviors of water. We have investigated and visualized the donation of covalent character from covalent (sigma) to hydrogen bonds by calculating the eigenvector coupling properties of quantum theory of atoms in molecules (QTAIM), stress tensor σ ( r ), and Ehrenfest Force F ( r ) on the F ( r ) molecular graph. The next-generation three-dimensional (3-D) bond-path framework sets are presented, and only the F ( r ) bond-path framework sets reproduce the earlier finding on the coupling between covalent (sigma) and hydrogen bonds that possess a degree of covalent character. Exploration of the bond-path between the covalent (sigma) and hydrogen bond's critical points provides an explanation for the previously obtained coupling results. The directional character of the covalent (sigma) and hydrogen bonds' 3-D bond-path framework sets for the F ( r ) explains differences found in the earlier results from QTAIM and the stress tensor σ ( r ). 相似文献
879.
建立了深共熔溶剂-高效液相色谱联用提取测定环境水样中3种药品和个人护理品(PPCPs)的方法。通过优化前处理条件,3种PPCPs(氯霉素、氯苯甘醚和萘普生)利用氯化胆碱-乙二醇深共熔溶剂为提取剂,经超声功率120 W下超声波提取5 min,离心转速9000 r/min下离心10 min富集提取。采用外标法定量分析,在5.0~200.0 mg/L范围内线性关系良好,相关系数r≥0.9998。3种环境水样中PPCPs的回收率为81.4%~94.8%,相对标准偏差分别为1.5%,0.4%和0.3%。氯霉素、氯苯甘醚和萘普生的方法检出限(LODs)分别为0.9,3.3,1.6 mg/L,定量限(LOQs)分别为3.1,12.2,5.0 mg/L。方法能够满足环境水样中3种PPCPs的检测需求。 相似文献
880.
综述了水和白酒中异味物质检测的样品前处理方法(包括液液萃取、固相萃取、液相微萃取、固相微萃取、搅拌棒吸附萃取、吹扫捕集、顶空等)和检测方法(包括气相色谱法、气相色谱-质谱法、气相色谱-飞行时间质谱法)的研究进展(引用文献52篇)。 相似文献