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排序方式: 共有232条查询结果,搜索用时 15 毫秒
1.
《International Journal of Hydrogen Energy》2022,47(10):6710-6720
Herein, molybdenum disulfide nanoflakes decorated copper phthalocyanine microrods (CuPc-MoS2) are synthesized via two step simple hydrothermal method. The as synthesized hybrid along with pure molybdenum disulfide (MoS2) nanoflower and pure copper phthalocyanine (CuPc) microrods are well characterized by various techniques that confirm phase, morphology, elemental compositions etc. Next, electrocatalytic oxygen reduction reaction towards fuel cell is investigated in alkaline medium and obtained results proclaim that our CuPc-MoS2 heterostructure outperforms the other two constituent materials. Efficient oxygen reduction is achieved following four electron pathway by CuPc-MoS2 whereas partial reduction is done through two electron process by CuPc and MoS2 separately. Long-time durability test reveals almost 97.6% retention after 8000s that eventually dictate us that CuPc-MoS2 heterostructure can be the efficient cathode electrocatalyst for future generation fuel cell. 相似文献
2.
《International Journal of Hydrogen Energy》2022,47(26):12903-12913
Oxygen evolution reaction (OER) plays a decisive role in electrolytic water splitting. However, it is still challengeable to develop low-cost and efficient OER electrocatalysts. Herein, we present a combination strategy via heteroatom doping, hetero-interface engineering and introducing conductive skeleton to synthesize a hybrid OER catalyst of CNT-interconnected iron-doped NiP2/Ni2P (Fe-(NiP2/Ni2P)@CNT) heterostructural nanoflowers by a simple hydrothermal reaction and subsequent phosphorization process. The optimized Fe-(NiP2/Ni2P)@CNT catalyst delivers an ultralow Tafel slope of 46.1 mV dec?1 and overpotential of 254 mV to obtain 10 mA cm?2, which are even better than those of commercial OER catalyst RuO2. The excellent OER performance is mainly attributed to its unique nanoarchitecture and the synergistic effects: the nanoflowers constructed by a 2D-like nanosheets guarantee large specific area and abundant active sites; the highly conductive CNT skeleton and the electronic modulation by the heterostructural NiP2/Ni2P interface and the hetero-atom doping can improve the catalytic activity; porous nanostructure benefits electrolyte penetration and gas release; most importantly, the rough surface and rich defects caused by phosphorization process can further enhance the OER performance. This work provides a deep insight to boost catalytic performance by heteroatom doping and interface engineering for water splitting. 相似文献
3.
《International Journal of Hydrogen Energy》2021,46(69):34287-34297
Developing efficient and stable non-noble metal oxygen evolution reaction (OER) electrocatalysts for sustainable overall water-splitting is extremely desirable but still a great challenge. Herein, we developed a facile strategy to fabricate Co3O4–CoOOH heterostructure nanosheet arrays with oxygen vacancies grown on carbon paper (Co3O4–CoOOH/CP). Benefiting from the unique 3D architecture, large surface area, synergistic effects between Co3O4, CoOOH and oxygen vacancies, the obtained self-supporting Co3O4–CoOOH/CP presents excellent electrocatalytic OER activity (low overpotentials of 245 and 390 mV at 10 and 100 mA cm−2) and robust long-term stability in alkaline condition. The present strategy provides the opportunities for the future rational design and discovery of high-performance non-noble metal based electrocatalysts for advanced water oxidation and beyond. 相似文献
4.
Yanlong Shi Xiaojuan Feng Haiyu Guan Jiahua Zhang Zhongai Hu 《International Journal of Hydrogen Energy》2021,46(12):8557-8566
Constructing high-efficient and nonprecious electrocatalysts is of primary importance for improving the efficiency of water splitting. Herein, a novel sunflower plate-like NiFe2O4/CoNi–S nanosheet heterostructure was fabricated via facile hydrothermal and electrodeposition methods. The as-fabricated NiFe2O4/CoNi–S heterostructure array exhibits remarkable bifunctional catalytic activity and stability toward oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline media. It presents a small overpotential of 219 mV and 149 mV for OER and HER, respectively, to produce a current density of 10 mA cm?2. More significantly, when the obtained electrodes are used as both the cathode and anode in an electrolyzer, a voltage of 1.57 V is gained at 10 mA cm?2, with superior stability for 72 h. Such outstanding properties are ascribed to: the 3D porous network structure, which exposes more active sites and accelerates mass transfer and gas bubble emission; the high conductivity of CoNi–S, which provides faster charge transport and thus promotes the electrocatalytic reaction of the composites; and the effective interface engineering between NiFe2O4 (excellent performance for OER) and CoNi–S (high activity for HER), which leads to a shorter transport pathway and thus expedites electron transfer. This work provides a new strategy for designing efficient and inexpensive electrocatalysts for water splitting. 相似文献
5.
异质谷间转移电子器件的计算机模拟 总被引:2,自引:1,他引:1
薛舫时 《固体电子学研究与进展》1995,15(2):118-124
使用弛豫时间近似求出了描述两能谷间电子交换的方程。在此基础上建立了双能谷电子的连续性方程和油松方程。对具体的GaAs/AlxGa1-xAs异质谷间转移电子器件结构求解了这些方程组,得到了直流工作时器件内的电场分布、双能谷中载流子的布居以及两个能谷的电流分布。这些结果正好和常规Gunn器件相反,说明了两种器件的不同工作机理。最后通过对低Al组份势垒结构的计算说明了X谷电子注入对器件工作的重要作用。 相似文献
6.
Suwaree Suraprapapich Supachok Thainoi Songphol Kanjanachuchai Somsak Panyakeow 《Solar Energy Materials & Solar Cells》2006,90(18-19):2968-2974
InAs self-assembled quantum dots (SA-QDs) were incorporated into GaAlAs/GaAs heterostructure for solar cell applications. The structure was fabricated by molecular beam epitaxy on p-GaAs substrate. After the growth of GaAs buffer layer, multi-stacked InAs QDs were grown by self-assembly with a slow growth rate of 0.01 ML/s, which provides high dot quality and large dot size. Then, the structure was capped with n-GaAs and wide band gap n-GaAlAs was introduced. One, two or three stacks of QDs were sandwiched in the p–n heterojunction. The contribution of QDs in solar cell hetero-structure is the quantized nature and a high density of quantized states. I–V characterization was conducted in the dark and under AM1 illumination with 100 mW/cm2 light power density to confirm the solar cell performance. Photocurrent from the QDs was confirmed by spectral response measurement using a filtered light source (1.1-μm wavelength) and a tungsten halogen lamp with monochromator with standard lock-in technique. These experimental results indicate that QDs could be an effective part of solar cell heterostructure. A typical I–V characteristic of this yet-to-be-optimized solar cell, with an active area of 7.25 mm2, shows an open circuit voltage Voc of 0.7 V, a short circuit current Isc of 3.7 mA, and a fill factor FF of 0.69, leading to an efficiency η of 24.6% (active area). 相似文献
7.
Yanhua Song Jianjian Yi Junjie Yuan Ting Fei Xianglin Zhu Wenshu Yang Huaming Li Hui Xu 《International Journal of Hydrogen Energy》2021,46(39):20516-20523
Despite that several strategies have been demonstrated to be effective for improving the catalytic hydrogen evolution activity of bulky g-C3N4, the large-scale hydrogen production over g–C3N4–based photocatalysts still confronts a big challenge. Here, a two-step calcination method is presented in constructing metal oxide/two-dimensional g-C3N4, i.e., Ta2O5/2D g-C3N4 photocatalyst. Thanks to the superiority of the synthetic method, nanostructure engineering forming 2D structure, and surface assembly with another semiconductor, can be realized simultaneously, in which ultrathin structure of 2D g-C3N4 and strong interfacial coupling between two components are two important characteristics. As a result, the structure engineered Ta2O5/2D g-C3N4 induces high photocatalytic hydrogen evolution half reaction rate of ~19,000 μmol g?1 h?1 under visible light irradiation (λ > 400 nm), and an external quantum efficiency (EQE) of 25.18% and 12.48% at 405 nm and 420 nm. The high photocatalytic performance strongly demonstrates the advance of the synchronous engineering of nanostructure and construction of heterostructure with tight interface, both of which are beneficial for the fast charge separation and transfer. 相似文献
8.
《International Journal of Hydrogen Energy》2022,47(90):38124-38133
The construction of a bifunctional electrocatalyst with excellent performance and low cost plays a key role in the application prospect of renewable energy. Herein, nickel sulfide/CoFe layered double hydroxide heterostructures on nickel foam (NiS/LDH/NF) have been constructed by using hydrothermal and electro-deposition methods. The amorphous nickel sulfide is deposited on the surface of crystalline LDH mesh-like nanosheets to form a hierarchical flower-like structure. The deposition of amorphous NiS can control the morphology and modulate the electronic structure of NiS/LDH/NF. The obtained NiS/LDH/NF is employed as a bifunctional catalyst for overall water splitting, which can achieve a current density of 10 mA cm?2 at a low voltage of 1.51 V in 1 M KOH. The results show that the high electrocatalytic activity is ascribed to the formation of amorphous NiS/crystalline LDH heterostructure with abundant surface defects and active sites. The synthetic strategy holds a great promise for accelerating the development of hydrogen energy by highly efficient electrocatalytic production of hydrogen. 相似文献
9.
《International Journal of Hydrogen Energy》2021,46(80):39822-39829
A novel visible-light active MoO3/N–MoS2 heterostructure photocatalyst was fabricated via hydrothermal process. The structure, morphology and optical characteristics were studied using X-ray diffraction (XRD) technique, scanning electron microscopy (SEM), UV–visible and photoluminescence (PL) spectroscopies. The results indicated that loading pf MoO3 and nitrogen doping played main influence role in advancing the morphology and optical characteristics. Upon visible photo-illumination, the MoO3/N–MoS2 sample displayed superior photocatalytic H2-production activity (118 μ mol h−1g−1), which was about four-time higher than that of pure MoS2 (30 μ mol h−1g−1). The enhancement in photocatalytic performance of MoO3/N–MoS2 photocatalyst can be ascribed to the development of direct Z-scheme heterostructure, which promoted the photo-excited electrons/holes transfer and separation. The recycling experiment verified that the MoO3/N–MoS2 photocatalyst had superior cyclic activity and stability, implying promising applications in energy field. 相似文献
10.
Charles Musca Jaroslaw Antoszewski John Dell Lorenzo Faraone Józef Piotrowski Zenon Nowak 《Journal of Electronic Materials》1998,27(6):740-746
This paper describes a new multi-heterojunction n
+pp photovoltaic infrared photodetector. The device has been developed specifically for operation at temperatures of 200–300K
in the long wavelength (8–14 μm) range of the infrared spectrum. The new structure solves the perennial problems of poor quantum
efficiency and low dynamic resistance found in conventional long wavelength infrared photovoltaic detectors when operated
near room temperature. Computer simulations show that devices with properly optimized multiple heterojunctions are capable
of achieving the performance limits imposed by the statistical nature of thermal generation-recombination processes. In order
to demonstrate the technology, multiple heterojunction devices have been fabricated on epilayers grown by isothermal vapor
phase epitaxy of HgCdTe and in situ As p-type doping. The detector structures were formed using a combination of conventional dry etching, angled ion milling,
and angled thermal evaporation for contact metal deposition. These multi-junction n
+pp HgCdTe heterostructure devices exhibit performances which make them useful for many applications. D* of optically immersed
multiple heterostructure photovoltaic detectors exceeding 108cmHz1/2/W were measured at λ=10.6 μm and T=300K. 相似文献