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排序方式: 共有845条查询结果,搜索用时 15 毫秒
1.
Lili Hou Axel Olesund Shameel Thurakkal Xiaoyan Zhang Bo Albinsson 《Advanced functional materials》2021,31(47):2106198
Developing high-performance visible-to-UV photon upconversion systems based on triplet–triplet annihilation photon upconversion (TTA-UC) is highly desired, as it provides a potential approach for UV light-induced photosynthesis and photocatalysis. However, the quantum yield and spectral range of visible-to-UV TTA-UC based on nanocrystals (NCs) are still far from satisfactory. Here, three different sized CdS NCs are systematically investigated with triplet energy transfer to four mediators and four annihilators, thus substantially expanding the available materials for visible-to-UV TTA-UC. By improving the quality of CdS NCs, introducing the mediator via a direct mixing fashion, and matching the energy levels, a high TTA-UC quantum yield of 10.4% (out of a 50% maximum) is achieved in one case, which represents a record performance in TTA-UC based on NCs without doping. In another case, TTA-UC photons approaching 4 eV are observed, which is on par with the highest energies observed in optimized organic systems. Importantly, the in-depth investigation reveals that the direct mixing approach to introduce the mediator is a key factor that leads to close to unity efficiencies of triplet energy transfer, which ultimately governs the performance of NC-based TTA-UC systems. These findings provide guidelines for the design of high-performance TTA-UC systems toward solar energy harvesting. 相似文献
2.
Qingna Gong Songtao Cao Yu Zhou Ruixin Wang Weizhou Jiao 《International Journal of Hydrogen Energy》2021,46(41):21442-21453
Ni2P nanoparticles and CdS nanorods were grew together on a mesoporous g-C3N4 through a facile in-situ solvothermal approach. Under visible light (λ > 400 nm), the as-prepared ternary PCN–CdS-5% Ni2P composite displays a high H2 evolution rate with 2905.86 μmol g?1 h?1, which is about 14, 18 and 279 times that of PCN–CdS, PCN–Ni2P and PCN, respectively. The enhanced photocatalytic activity is mainly attributed to the improved separation efficiency of the photocarriers by the type II PCN–CdS heterojunction and the effective extraction of photogenerated electrons by Ni2P. Meanwhile, Ni2P acts as co-catalyst to provide the photocatalytic active site for hydrogen reduction. In addition, PCN–CdS-5% Ni2P composite exerts good stability in 12-h cycles. 相似文献
3.
Cadmium Sulfide and Ferrous doped Cadmium Sulfide thin films have been prepared on different substrates using an electrodeposition technique. Linear sweep voltammetric analysis has been carried out to determine deposition potential of the prepared films. X-ray diffraction analysis showed that the prepared films possess polycrystalline nature with hexagonal structure. Surface morphology and film composition have been analyzed using Scanning electron microscopy and Energy dispersive analysis by X-rays. Optical absorption analysis showed that the prepared films are found to exhibit Band gap value in the range between 2.3, 2.8 eV for Cadmium Sulfide and Ferrous doped Cadmium Sulfide. 相似文献
4.
《International Journal of Hydrogen Energy》2022,47(16):9566-9578
The construction of heterostructure is an effective strategy to synergetically couple wide-band-gap with the narrow-band-gap semiconductor with a mediate optical property and charge transfer capability. Herein, the Z-Scheme CdS/ZnSnO3 (CdS/ZSO) heterostructures were constructed by anchoring CdS nanoparticles on the surface of double-shell hollow cubic ZnSnO3 via the hydrothermal method. The direct recombination of excited electrons in the conduction band (CB) of ZSO and holes in the valence band (VB) of CdS via d-p conjugation at the interface greatly accelerated the internal electric field (IEF). The transfer mode follows the Z-Scheme mechanism, where CdS/ZSO synergistically facilitates the efficient charges transfer from CdS to ZnSnO3 through the intimate interface. Here, ZnSnO3 and CdS serve as an oxidation photocatalyst (OP) and reduction photocatalyst (RP), respectively. Thus, it can promote synergistically the oxidation half-reaction and reduction half-reaction of H2 evolution. The density-functional theory (DFT) calculation further confirms the charges transfer from CdS to ZnSnO3. The hydrogen evolution of 5% CdS/ZSO heterostructure reached 1167.3 μmol g?1, which was about 8 and 3 folds high compared to pristine ZSO (141.9 μmol g?1) and CdS (315.5 μmol g?1), during 3 h of reaction respectively. Furthermore, the CdS/ZSO heterostructures could suppress the photo corrosion of CdS, resulting in its high stability. This work is expected to enlighten the rational design of heterostructure for OP and RP to promote the hybrid heterostructures photocatalytic H2 evolution. 相似文献
5.
《International Journal of Hydrogen Energy》2020,45(11):6476-6486
Synergistic the modulation of photon absorption capability and interfacial charge transfer of the photocatalyst are highly required for developing high-performance heterojunction photocatalysts. The ternary CdS-graphene quantum dots-titanate nanotubes (CdS-GQDs-TNTs) nanocomposite have been prepared by an in situ growth method. The physicochemical characterization reveals that the GQDs are firmly decorated on both inner and outer surface of TNT through the formation of Ti–O–C chemical bonding, and CdS QDs are loaded on the outer surface of TNTs through strong interfacial interaction. The intimate integrated CdS-GQDs-TNTs nanocomposite exhibits much superior photocatalytic performance toward H2 production compared with binary GQDs-TNTs and pure TNTs photocatalyst, which can be attributed to the combined interaction of the stronger visible light harvesting, the longer lifetime of photogenerated electron−hole pairs, faster interfacial charge transfer rate, fast and long-distance electron transport pass. The interfacial charge transfer mechanism of CdS-GQDs-TNTs ternary composite are proposed based on photoelectrochemical measurements. 相似文献
6.
《International Journal of Hydrogen Energy》2020,45(53):28437-28446
Exploiting efficient and stable noble metal-free hydrogen evolution catalysts for water splitting is of great importance. In this work, NixCo1-xO@C/CdS hybrid is successfully fabricated through an electrostatic interaction of oppositely charged nanoparticles on their surfaces. The resulting NixCo1-xO@C nanoboxes cocatalysts which were derived from NiCo-LDH@ZIF-67 with Ni–Co layered double hydroxides (LDH) decorated with ZIF-67 precursor exhibited improved hydrogen production rate compared with bare CdS semiconductor from 0.7 mmol g−1 h−1 to 56 mmol g−1 h−1. It is demonstrated that the electrostatic interaction between the two surface charged nanoparticles of NixCo1-xO@C and CdS play an important role in migrating and separating of photogenerated charge carriers. The synthesized NixCo1-xO@C as excellent candidates for cost-effective cocatalysts is aimed to substitute for noble metals in photocatalytic H2 evolution. 相似文献
7.
L.C. Souza A.C.A. Silva N.O. Dantas P.C. Morais S.W. da Silva 《Ceramics International》2018,44(1):208-215
Successful fabrication of glass-based hybrid nanocomposites (GHNCs) incorporating Ag, core-shell CdSe/CdS and CdSxSe1?x nanoparticles (NPs) is herein reported. Both metallic (Ag) and semiconductor (CdSe/CdS) NPs were pre-synthesized, suspended in colloids and added into the sol-gel reaction medium which was used to fabricate the GHNCs. During fabrication of the nanocomposites a fraction (20–60%) of core-shell CdSe/CdS NPs was alloyed into CdSxSe1?x (0.20 < x < 0.35) NPs without changing morphology. Modulation of in situ alloying is possible via the relative content of organics added into the sol-gel protocol. Within colloids Ag (core-shell CdSe/CdS) NPs presented average diameter and polydispersity index of 49.5 nm (4.2 nm) and 0.41 (0.21), respectively. On the other hand, the Ag (core-shell CdSe/CdS) NPs’ average diameter and polydispersity index assessed from the GHNCs were respectively 51.5 nm (4.1 nm) and 0.43 (0.25), revealing negligible aggregation of the nanophases within the glass template. The new GHNCs herein introduced presented two independent excitonic transitions associated to homogenously dispersed semiconductor NPs, peaking around 420 nm (core-shell CdSe/CdS) and 650 nm (CdSxSe1?x) and matching the plasmonic resonance (Ag NPs) in the 400–500 nm range. We envisage that the new GHNCs represent very promising candidates for superior light manipulation while illuminated with multiple laser beams in quantum interference-based devices. 相似文献
8.
《International Journal of Hydrogen Energy》2022,47(52):22045-22053
As a novel co-catalyst, Ti3C2 MXene has an excellent prospect in the field of photocatalysis. Herein, the 2D/3D Ti3C2 MXene@CdS nanoflower (Ti3C2@CdS) composite was successfully synthesized by a hydrothermal method. The combination of 2D Ti3C2 MXene and 3D CdS nanoflowers can promote carrier transfer and separation, which can improve the performance of CdS. Compared to pure CdS nanoflowers, Ti3C2@CdS composite presents lower photoluminescence intensity, longer fluorescence lifetime, higher photocurrent density and smaller electrochemical impedance. The Ti3C2@CdS composite with 15 wt% Ti3C2 adding amount presents high photocatalytic hydrogen evolution activity (88.162 μmol g?1 h?1), 91.57 times of pure CdS. The improved photocatalytic activity of Ti3C2@CdS composite is ascribed to the addition of lamellar Ti3C2 MXene, which improves the electrical conductivity of the photocatalytic system and effectively accelerates the excited electrons transfer from CdS to Ti3C2 MXene. 相似文献
9.
《International Journal of Hydrogen Energy》2022,47(76):32531-32542
Constructing active sites on photocatalysts is one of the most effective approaches for promoting photocatalytic H2 production activity. In this paper, a p-type semiconductor α-NiS is in-situ grown on an n-type semiconductor CdS by a simple solid state method, which results in a strong interfacial contact between α-NiS and CdS. Benefitting from the built-in electric field caused by a p-n junction, the photoinduced electrons of CdS and holes of α-NiS migrate to their interface and recombine rapidly, which results in the formation of a Z system. The more negative CB potential of α-NiS/CdS possesses stronger ability to reduce H+ to H2, thereby exhibiting higher photocatalytic H2 evolution activity. Furthermore, the strong interface contact is beneficial to the charge migration and promotes the charge separation efficiency. The H2 evolution rate of 1.0% α-NiS/CdS reaches 9.8 mmol h?1 g?1, corresponding to an AQY of 65.7% at λ = 420 nm. 相似文献
10.
采用电化学沉积方法制备CdS/TiO2电极并研究其光电催化性能,比较了不同电压、反应物浓度、不同电解质等条件下CdS/TiO2电极所显示的光电性能。另外,将CdS/TiO2与CdS/Ti电极进行光电性能比较,得出了在相同沉积时间下CdS/TiO2电极的光电性能比CdS/Ti电极稳定,产生的光电流略有提高的结论,在多数方面都优于CdS/Ti电极。 相似文献