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排序方式: 共有351条查询结果,搜索用时 156 毫秒
1.
《International Journal of Hydrogen Energy》2022,47(12):7783-7792
Efficient and sustainable Janus catalysts toward hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are highly desirable for future hydrogen production via water electrolysis. Herein we report an active Janus electrocatalyst of amorphous-crystalline cobalt-molybdenum bimetallic phosphide heterostructured nanosheets on nickel foam (CoMoP/CoP/NF) for efficient electrolysis of alkaline water. As-reported CoMoP/CoP/NF consists of amorphous bimetal phosphide nanosheets doped with crystalline CoMoP/CoP heterostructured nanoparticles on NF. It can efficiently catalyze both HER (η = 127 mV@100 mA cm?2) and OER (η = 308 mV@100 mA cm?2) in alkaline electrolyte with long-term durability. Serving as anode and cathode of water electrolyzer, CoMoP/CoP/NF generates electrolytic current of 10, 50 and 100 mA cm?2 at low voltage of 1.50, 1.59, and 1.67 V, respectively. 相似文献
2.
《International Journal of Hydrogen Energy》2020,45(11):6519-6528
MoSe2 ultrathin nanospheres with three-dimensional network structure (MSS) were prepared by improved solvothermal method. These MoSe2 nanospheres are only 10 nm in size and actually composed of ultra-thin MoSe2 nanosheets with a thickness of only 2–3 molecular layers. Compared with the MoSe2 nanosheets (6–8 molecular layer thicknesses) of the three-dimensional flower structure (MSF) prepared by ordinary hydrothermal method, the MSS are thinner resulting in higher specific surface area of 5 times than that of MSF, and the light absorption ability at all UV–vis spectrum is stronger. The photocatalytic and photoelectrochemistry results show that the photocatalytic activity of MSS is 17 times that of the MSF, and the photoelectrochemical performance is twice. The results of electrochemical impedance spectroscopy and fluorescence spectroscopy confirmed that the MoSe2 ultra-thin nanospheres with three-dimensional network structure have lower internal resistance and higher carrier transport and separation efficiency. In the most important three aspects that determine the photoelectrochemical performance of photocatalyst: specific surface area, light absorption capacity, carrier transport and separation efficiency, MSS exceed MSF. This three-dimensional network nanospheres structure can improve the performance of MoSe2. This research successfully demonstrates the enhancement of the properties of MoSe2 two-dimensional materials through structural regulation. 相似文献
3.
《International Journal of Hydrogen Energy》2020,45(16):9635-9647
In this work, a cascade structure among ZnSe, carbon membrane and TiO2 NTAs was constructed precisely. This carbon membrane bridged ZnSe and TiO2 composite exhibits excellent H2 evolution activity, the H2 evolution rate of ZnSe/C/TiO2 NTAs (866.76 μmol/cm2) is about 6.95 times higher than that of pure TiO2 NTAs (124.64 μmol/cm2) after 200 min irradiation. The introduction of carbon membrane can greatly facilitate the electron transfer from ZnSe to TiO2, ZnSe/C/TiO2 ternary composite exhibits the highest transient photocurrent density (1.05 mA/cm2) and the lowest impedance (677.6 Ω) among all the samples. Besides, the contact between TiO2 and electrolyte is improved after introducing carbon membrane, therefore C/TiO2 NTAs shows more positive flat band potential of (1.86 V) compared with TiO2 NTAs (0.50 V). It is also found that pure carbon powder can achieve H2 production under visible light irradiation, its sensitization effect can further improve photocurrent density of the composite under 500 nm light radiation, the electrons produced in carbon film can inject into TiO2, and holes from TiO2 can quickly transfer to carbon film, leading to excellent H2 evolution efficiency. 相似文献
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The performance of organic semiconductor devices is strongly affected by the interface energetics at the junctions between the constituent materials. A large group of organic semiconductors consists of rodlike small molecules that crystallize upon deposition with a molecular orientation dependent on the specifics of the molecule–molecule and molecule–substrate interactions. By means of Kelvin probe force microscopy (KPFM), this work studies naphthyl end-capped oligothiophene, 5,50-bis(naphth-2-yl)-2,20-bithiophene (NaT2), deposited on samples of pristine and samples of graphene-covered . The crystal molecular orientation of NaT2 is dependent on the substrate on which it is deposited. On , the NaT2 molecules are predominately upright standing, forming crystallites with distinct terrace heights of . Measurements indicate formation of an initial wetting layer in the NaT2- system for the upright standing molecules. When deposited on graphene, the molecules additionally form fibrous structures with heights of consisting of molecules lying down (face-on orientation). Using KPFM, a difference in the local contact potential difference (CPD) of upright standing NaT2 and face-on oriented structures on graphene is measured to be , indicating a work function difference between the two system configurations, which is confirmed through Density Functional Theory calculations. 相似文献
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以4-(苯并[d]噻唑-2-基)-N,N-二甲基苯胺(1)、L-丝氨酸作为主配体和辅助配体,合成了一种新型环金属铱配合物(2),所有化合物的结构通过1H NMR、MS和IR进行了表征确认。通过紫外吸收光谱和荧光发射光谱研究了铱配合物(2)的光物理性质,并采用含时密度泛函理论(TDDFT)对其最低能量电子跃迁和最低三重激发态进行了计算。而且铱配合物(2)的荧光发射光谱可选择性地被汞离子猝灭,暗示着此配合物可作为一种高效的turn-off型汞离子磷光传感器。 相似文献
9.
《International Journal of Hydrogen Energy》2019,44(10):4821-4831
Construction of semiconductor heterojunctions can effectively accelerate the separation of photo-induced charge carriers and thereby enhance photocatalytic activity. Here, NiSe was used as an effective co-catalyst to construct an active NiSe/TiO2 heterojunction for improving the photocatalytic H2 production of TiO2. The resultant 10%NiSe/TiO2 heterojunction exhibited 11 times higher photocatalytic H2-production activity than that of bare TiO2. The NiSe/TiO2 heterojunction and the photo-reduction of partial Ni2+ to Ni0 notably accelerated the separation and transfer of photo-excited electron-hole pairs, and thus resulted in obvious improvement of H2-evolution activity. This work holds promise for the application of NiSe in photocatalysis as a high-efficiency photocatalytic cocatalyst. 相似文献
10.
Xiaobao Li Ruyi Zou Yanyan Niu Wei Sun Xinlong Tian 《International Journal of Hydrogen Energy》2018,43(48):21791-21797
A facile and effective approach was developed for the preparation of mesoporous Fe-NC by pyrolyzing the mixture of FeCl2, urea, (NH4)2MoO7, phthalic anhydride and SBA-15, during which the in-situ formation of iron phthalocyanine is confirmed. The obtained catalyst exhibits high catalytic activity towards ORR, whose half-wave potential can be 53 mV more positive than that of commercial Pt/C catalyst. Besides, the catalyst also exhibits high selectivity of four electron path, along with excellent stability and methanol tolerance in alkaline media. Based on the characterization results, we suggest, the higher surface areas, highly porous structures induced by SBA-15 addition, as well as high graphitic N content should be the proper origins for its outstanding catalytic performance. 相似文献