Catalysts
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2019
·Vol. 9
·期 4
·352
·
IF 3.444
Dongdong Wang,Shuangde Li,Yingchao Du,Xiaofeng Wu,Yunfa Chen
Rational design LDHs (layered double hydroxides) with 3D hierarchical hollow structures have generated widespread interest for catalytic oxidation due to the high complexity in shell architecture and composition. Herein, we reported a handy two-step method to construct a 3D hierarchical NiCo2O4/NiO nanocage. This synthetic strategy contains a partial in situ transformation of ZIF-67 (zeolitic imidazolate framework-67) into Co-NiLDH yolk-shelled structures following ethanol etching, and a structure-preserved transformation from Co-NiLDH@ZIF-67 to a biphase nanocage following calcination. CoNi-yh-T (varied reaction time and calcination temperature) nanocages were investigated systematically by Brunauer–Emmett–Teller (BET), X-ray photoelectron spectroscopy (XPS), H2- temperature-programmed reduction (TPR), NH3-temperature-programmed desorption (TPD) and studied for toluene oxidation. The CoNi-6h-350 sample showed much higher activity with 90% toluene conversion (T90) at 229 °C at a high space velocity (SV = 60,000 mL g−1h−1) than other catalysts (T90>240 °C). Abundant surface high valence Co ions caused by the novel hierarchical nanostructures, together with adsorbed oxygen species and abundant medium-strength surface acid sites, played a key role for catalytic activities.
研究领域:
材料科学
·
催化化学
✓ 已验证
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2025
·
IF 5.4
Xuan Li,Yuyan Cao,Yihui Shen,Yulin Wu,Shicong Cui,Lingli Cheng,Xuechun Yang,Zheng Jiao
Nowadays, designing sensing materials possessing both high sensitivity and humidity resistance is still a challenge in the field of sensing materials. In this work, a ternary Ag nanoparticles decorated NiCo 2 O 4 /NiO (Ag/NiCo 2 O 4 /NiO) composite with hollow nanocage structure has been successfully obtained, which uses ZIF-67 as a template combined with self-etching method, followed by NaBH 4 reduction of silver ions. For the synergistic effect of the novel morphology, the presence of Ag nanoparticles and hydroxyl absorbent NiO, and the formation of p-p heterojunction between NiCo 2 O 4 and NiO, Ag/NiCo 2 O 4 /NiO exhibits good humidity resistance and high-sensitive to n-butanol. The mesoporous hollow nanocage morphology not only provides abundant adsorption sites for target gases, but also facilitates the diffusion of water molecules. The doping of Ag nanoparticles can regulate the adsorption of oxygen on the surface of gas sensing materials, improving the sensitivity while suppressing the hydroxyl poisoning reaction process. The hydroxyl absorbent NiO in Ag/NiCo 2 O 4 /NiO can both directly absorb water and form p-p heterojunction structure with NiCo 2 O 4 , which improves sensor performance while suppressing hydroxyl poisoning. In the gas sensing tests, the optimal Ag/NiCo 2 O 4 /NiO composites can achieve a high response value of 31.41, as well as rapid response/recovery times (65 s/47 s) to 100 ppm n-butanol at the working temperature of 170 °C. Moreover, it displays a wide detection range (1–120 ppm), a low detection limit (0.27 ppm), excellent selectivity to n-butanol, and superior long term stability (maintaining a response value of 84.68 % after 14 days). Notably, the optimal Ag/NiCo 2 O 4 /NiO demonstrates great humidity-tolerant ability with a response values fluctuation of 16 % under the range of 33 %-80 % relative humidity. This research provides a feasible approach for designing practical gas sensing materials with high sensitivity and moisture resistance.
研究领域:
材料科学
·
纳米技术
·
气体传感
·
化学传感器
·
环境监测
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Wenming Zhang,Pin Cao,Zihao Zhang,Yajun Zhao,Yu Zhang,Ling Li,Kun Yang,Xiaowei Li,Lin Gu
Rational design of nanostructured metal oxides with carbon substrates is urgently needed to improve the electrochemical properties of sodium-ion batteries (SIBs). In this paper, the preparation of one-dimensional (1D) metal-organic frameworks grown on polymer(Co/Ni) fiber films via a feasible electrospinning method and in situ growth strategy is reported. After successive carbonization and oxidation heat-treatments, hierarchical heteroatom-doped carbon nanofibers decorated with several nanocomposites (denoted as NiCo 2 O 4 /NiO/carbon nanofibers) were obtained. When their electrochemical properties were evaluated by testing Na half-cells, the resultant sample displayed a high sodium-storage capacity of 210 mAh g −1 after 200 cycles at a current density of 100 mA g −1 and an outstanding rate capability. The enhancement of the sodium-storage performance of NiCo 2 O 4 /NiO/carbon nanofibers was ascribed to the novel structure and the synergistic effect between Co/Ni-Oxide and carbon component. The 1D carbonized nanofibers are well intertwined to form a three-dimensional conductive matrix with heterogeneous particles embedded, which can effectively reduce the ionic diffusion distance and ensure high electronic mobility along their 1D geometry, leading to rapid diffusion kinetics. Furthermore, well-dispersed heterogeneous particles endow the composite high surface to exposure to the electrolyte, which can contribute to a high utilization rate.
研究领域:
材料科学
·
储能技术
·
电化学
·
纳米材料
·
金属有机框架（MOFs）
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2018
·
IF 3.779
Shan Yan,Lina Xu,Jun Jiang,Hongping Xiao,Xinhua Li
Single-material electrodes do not satisfy the demands of high-performance supercapacitors. To exploit the advantages of both oxides and carbon-based materials, a tightly packed Co 3 O 4 /NiCo 2 O 4 /NiO/C&S nanocomposite is fabricated by sintering a Co/Ni-based coordination complex precursor at 400 °C. The composites and basic components are characterized using various techniques, namely, X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy , Brunauer–Emmett–Teller specific surface area analysis, and elemental analysis . The electrochemical performance is analyzed by cyclic voltammetry , galvanostatic charge/discharge cycling, and electrochemical impedance spectrometry . A uniform nanocomposite was found to be formed of NiCo 2 O 4 , NiO, and Co 3 O 4 nanoparticles , incompletely carbonized C, and incompletely vulcanized S. When used as supercapacitor electrodes, the synthesized composites show extra-long cycling stability (>20,000 cycles) during the charge/discharge process. This improvement in the cycle life of the composites is attributed to its highly stable structure. The roles of C and S in forming a stable structure are investigated. The results show that a supercapacitor with electrodes made from the as-prepared Co 3 O 4 /NiCo 2 O 4 /NiO/C&S composite will be promising for commercial applications.
研究领域:
材料科学
·
电化学
·
能量存储
·
纳米材料
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）