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1.
《International Journal of Hydrogen Energy》2020,45(41):20851-20858
In this paper, Ag-based g-C3N4 composites have been successfully fabricated through two deferent synthetic methods: (i) a facile and efficient precipitation-calcination strategy (denoted as D–CN–xAg, x represents the dosage of Ag2CO3, the same below), (ii) a calcination method (denoted as Z–CN–xAg). All Ag-based g-C3N4 composites exhibit the enhanced photocatalytic activities under visible-light irradiation. Moreover, the optimal dosage of Ag2CO3 in the D–CN–xAg composite is found to be 5%, the corresponding hydrogen production capacity is 153.33 μmol g−1 h−1, which is 4.6 times higher than that of Z–CN–5%Ag composite. This might be attributed to appropriate content of metallic Ag and more active sites exposed on the surface of D–CN–5%Ag composite. Meanwhile, combining with photoelectrochemical results, it could be inferred that LSPR effect and the intimate interfacial between metallic Ag and g-C3N4 in the system play also important role for the improvement of photocatalytic activity. These results demonstrate that the appropriate loading of metallic Ag originated from Ag2CO3 into g-C3N4 could accelerate the separation and transfer of photogenerated electron-hole pairs, leading to the improvement of photocatalytic activity for hydrogen production from water splitting. Finally, a possible photocatalytic mechanism is proposed. 相似文献
2.
Ying Zhou Shengnan Wei Siyi Li Xudong Liu Xiaoqing Shu Xu Zhang Cheng Zhao Zepeng Qu Dawei Fang Zhaohong Zhang Jun Wang 《International Journal of Hydrogen Energy》2017,42(26):16362-16374
By using TiO2 and Ta2O5 colloids, a stable and efficient visible-light driven photocatalyst, Er3+:Y3Al5O12/TiO2Ta2O5/MoO2 composite membrane, was successfully prepared via sol–gel dip coating method at room temperature. The XRD, FTIR, SEM, TEM and EDX results confirm that approximately spherical Er3+:Y3Al5O12 nanoparticles were embedded in TiO2Ta2O5 matrix. UV–vis absorption and PL spectra of Er3+:Y3Al5O12 were also determined to confirm the visible absorption and ultraviolet emission. The photocatalytic hydrogen generation was carried out by using methanol as sacrificial reagent in aqueous solution under visible-light irradiation. Furthermore, some main influence factors such as heat-treated temperature, heat-treated time and molar ratio of TiO2 and Ta2O5 on visible-light photocatalytic hydrogen generation activity of Er3+:Y3Al5O12/TiO2Ta2O5/MoO2 composite membrane were studied in detail. The experimental results showed that the photocatalytic hydrogen generation activity of Er3+:Y3Al5O12/TiO2Ta2O5/MoO2 composite membrane heat-treated at 550 °C for 3.0 h was highest when the molar ratio of TiO2 and Ta2O5 was adopted as 1.00:0.50. And that a high level photocatalytic activity can be still maintained after four cycles. In addition, a possible mechanism for the visible-light photocatalytic hydrogen generation of the Er3+:Y3Al5O12/TiO2Ta2O5/MoO2 membrane was proposed based on PL spectra. 相似文献
3.
《International Journal of Hydrogen Energy》2022,47(13):8294-8302
Photocatalytic water splitting to produce hydrogen has attracted extensive attention and exhibited broad development prospects. In this work, CuInS2 microflowers were fabricated through the solvothermal method, and decorated with CdSe quantum dots on the surface. As-prepared CdSe/CuInS2 microflowers exhibited high photocatalytic hydrogen production activity (10610.37 μmol g?1 h?1) and high AQE of 48.97% at 420 nm. The enhanced photocatalytic hydrogen production activity owing to the construction of p-n heterostructure improved light absorption ability, increased electrons transfer efficiency and reduced recombination of photo-induced electrons and holes. Moreover, high stability and cyclic utilization of CdSe/CuInS2 microflowers were beneficial to photocatalytic hydrogen production application. 相似文献
4.
Ni(OH)2 modified Mn0.5Cd0.5S with efficient photocatalytic H2 evolution activity under visible-light
《International Journal of Hydrogen Energy》2020,45(41):21532-21539
Developing high-efficiency photocatalysts for water decomposition is one of the major challenges in converting solar energy to chemical energy. In this paper, Ni(OH)2 modified Mn0.5Cd0.5S solid solution without the use of precious metals is successfully synthesized via hydrothermal method followed by precipitation, the photocatalytic activity for hydrogen evolution and stability of composite samples present significant improvement with respect to the pristine Mn0.5Cd0.5S. These improvements are attributed to that Mn0.5Cd0.5S CB potential (−0.7 V vs. NHE) is more negative than the potential of Ni2+/Ni (−0.23 V vs. NHE), which promotes the transfer of photo-generated electrons from Mn0.5Cd0.5S CB to Ni(OH)2 for H2 production as well as partial reduction of Ni2+ to Ni0, leaving VB holes to oxidize the sacrificial reagents. The metal Ni atoms with conductivity and Ni(OH)2 nanoparticles not only boost the segregation and transfer of photo-induced carriers but also act as water-reduction promoter, thereby promoting the photocatalytic activity for hydrogen release. A novel visible light responsive MnxCd1-xS-based photocatalytic material promising for practical applications is provided in this subject. 相似文献
5.
(CuIn)xZn2(1-x)S2 (x = 0.01–0.5) microspheres were prepared by a simple hydrothermal method. They were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–Visible diffuse reflectance spectra (UV–Vis), Raman scattering spectra and Brunauer-Emmett-Teller (BET) surface area measurement. It was found that the (CuIn)xZn2(1-x)S2 samples formed solid solution only in the presence of surfactant cetyltrimethylammonium bromide (CTAB). CTAB enabled the increase of the surface area for the (CuIn)xZn2(1-x)S2 solid solutions. Diffuse reflection spectra of the solid solutions shifted monotonically to long wavelength side as the value of x increased. The photocatalytic H2 evolution activity under visible-light irradiation of the solid solutions was evaluated. The result showed that the activity depended on their corresponding compositions closely. Ru (1.5 wt%)-loaded (CuIn)0.2Zn1.6S2 showed the highest photocatalytic activity of 198.09 μmol h−1 under visible-light irradiation, and the apparent quantum yield amounted to 15.45% at 420 nm. Furthermore, the density functional theory (DFT) calculations showed that the solid solution with the ration of ZnS and CuInS2, 6:1, was a direct band gap semiconductor. The valence band consisted of the hybrid orbital of S 3p and Cu 3d and the conduction band consisted of In 5s5p orbital mixed with Zn 4s4p. The energy band structure resulted in the visible-light response of the solid solution, and affected its photocatalytic performance. 相似文献
6.
Liang Chen Kaisheng Xia Lizhen Huang Liwei Li Libin Pei Shunxin Fei 《International Journal of Hydrogen Energy》2013
This paper reports a facile method for the preparation of nitrogen-doped carbon nanotubes (N-doped CNTs) that shows enhanced hydrogen storage capacity. The synthesis method involves simple pyrolysis of melamine using FeCl3 as catalyst in tube furnace. The materials were characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, elemental analysis, Raman spectroscopy, and nitrogen adsorption–desorption analysis. The results indicated that the prepared N-doped CNTs have a bamboo-like structure with thin compartment layers. The nitrogen doping concentration, specific surface area, and total pore volume of the N-doped CNTs were determined to be 1.5 at%, 135 m2/g, and 0.38 cm3/g, respectively. The hydrogen adsorption measurements at 77 K showed that the N-doped CNTs exhibits gravimetric hydrogen uptake of 0.21 wt% at 1 bar and 1.21 wt% at 7 bar. At room temperature, hydrogen uptake as high as 0.17 wt% at 298 K and 19 bar is achieved, which is among the highest data reported for the N-doped carbon materials under the same condition. 相似文献
7.
Zhongli Li Xiaoping Chen Wenfeng Shangguan Yanjie Su Yijian Liu Xinwei Dong Poonam Sharma Yafei Zhang 《International Journal of Hydrogen Energy》2017,42(10):6618-6626
The photocatalytic water splitting strategy is one of the most promising ways to achieve clean and renewable solar-to-hydrogen energy conversion. In this study, a highly enhanced photocatalytic H2 production system has been achieved, using CdS nanoparticles (NPs) decorated on prickly Ni3S2 nanowires (NWs) as the light-driven photocatalyst. The photocatalyst was prepared by a co-precipitated method in which spiky Ni NWs were employed as starting material for prickly Ni3S2 NWs. Characterization analysis (XRD, TEM, XPS, etc.) show the high purity of Ni3S2/CdS hybrid structures and the well deposition of CdS NPs on prickly Ni3S2 NWs. Besides, the as synthesized Ni3S2/CdS photocatalyst exhibit reduced photoluminescence peak intensity, which means the Ni3S2 NWs functions as electron collector and transporter to quench the photoluminescence of CdS. This prickly Ni3S2/CdS nanocomposite demonstrates a 70 times higher H2 production rate than that of pure CdS and a quantum efficiency of 12.3% at the wavelength of 400 nm in the absence of noble metals. This enhanced H2 production activity is better than the one of CdS loaded with 0.5 wt% Pt. Our findings highlight the potential application of Ni3S2/CdS hybrid structures for visible light photocatalytic hydrogen yielding in the energy conversion field. 相似文献
8.
Xin Han Dongyu Xu Lin An Chengyi Hou Yaogang Li Qinghong Zhang Hongzhi Wang 《International Journal of Hydrogen Energy》2018,43(10):4845-4855
WO3/g-C3N4 two-dimensional (2D) composite photocatalysts were prepared through a simple hydrothermal method followed by a post thermal treatment. The H2 generation activity of these photocatalysts in the visible light was evaluated. The photocatalysts were characterized by X-ray powder diffraction, Fourier transform infrared spectra, transmission electron microscopy and UV–vis diffuse reflectance spectroscopy et al. These results show that the orthorhombic-phase WO3 nanoparticles with a grain size from 5 to 80 nm were successfully anchored on g-C3N4 nanosheets surface with intimate contact. Furthermore, the charge separation mechanisms of photo-generated charge carriers of the 2D WO3/g-C3N4 photocatalysts were further studied by photoelectrochemical response and electrochemical impedance spectroscopy. The result shows that the 2D WO3/g-C3N4 photocatalyst with 10 wt% WO3 possesses the maximum photocatalytic performance for H2 generation, as high as of 1853 μmol h?1 g?1, which is about 6.5 times higher than that of bare g-C3N4, indicating the fast injection of interface interaction between 2D g-C3N4 and WO3. The increased photocatalytic performance of the composite photocatalyst can be attributed to the enhanced absorption of visible light, the higher photo-generated electrons and holes separation efficiency and low recombination rate of electrons and holes generated by photoexcitation. 相似文献
9.
《International Journal of Hydrogen Energy》2020,45(11):6291-6301
The MoS2/Ti3C2 catalyst with a unique sphere/sheet structure were prepared by hydrothermal method. The MoS2/Ti3C2 heterostructure loading 30% Ti3C2 has a maximum hydrogen production rate of 6144.7 μmol g−1 h−1, which are 2.3 times higher than those of the pure MoS2. The heterostructure maintains a high catalytic activity within 4 cycles. The heterostructure not only effectively reduce the recombination of photogenerated electrons and holes, but also provide more activation sites, which promotes the photocatalytic hydrogen evolution reaction (HER). These works can provide reference for the development of efficient catalysts in photocatalytic hydrogen evolution. 相似文献
10.
Jie Dong Lixuan Duan Qiang Wu Weifeng Yao 《International Journal of Hydrogen Energy》2018,43(4):2139-2147
A series of 0.75 wt% Pt/CdS photocatalysts were successfully synthesized via a modified photoreduction process, with the assistance of a protective agent (polyvinylpyrrolidone, PVP) and/or structural inducer (NaI, NaBr, and NaCl). The physicochemical properties of the obtained 0.75 wt% Pt/CdS photocatalysts were characterized in more detailed. Their photocatalytic efficiencies were evaluated by visible-light photocatalytic hydrogen production. The results show that the photocatalytic activities of 0.75 wt% Pt/CdS photocatalysts for H2 production mainly depend on the type of structural inducer. Furthermore, a suitable ratio of PVP/NaI is necessary to optimize the photocatalytic performance of Pt/CdS composites. Notably, 0.75 wt% Pt/CdS (PVP/NaI = 4:1) gains the highest hydrogen production activity with a rate of 1155.8 μmol h?1, which is 1.8 times higher than that of 0.75 wt% Pt/CdS obtained from the traditional photoreduction method (640.9 μmol h?1) and 17.3 times higher than that of the bare CdS sample (66.9 μmol h?1). The as-prepared 0.75 wt% Pt/CdS photocatalyst (PVP/NaI = 4:1) also exhibits a good stability. An optimum ratio of PVP/NaI not only causes a decrease in particle size of Pt nanoparticles but also leads to an increase in BET specific surface area of Pt/CdS and an enhanced electron transfer capability of Pt nanoparticles, which should be responsible for the enhanced photocatalytic performance. 相似文献
11.
Xiaoyang Wang Xu Yang Lei Miao Jie Gao Liangpeng Wu Nan Wang Xinjun Li 《International Journal of Hydrogen Energy》2018,43(24):10950-10958
Exploring and developing novel semiconductor photo-catalysts for visible-light-driven water splitting are of great scientific significance to solve energy and environmental problems. Herein, Bismuth Selenide (Bi2Se3) nanosheets decorated with a thin layer of Bi2SeO2 to form Bi2Se3/Bi2SeO2 nanocomposites were successfully prepared using a conventional reflux and heating method. Fabricated Bi2Se3/Bi2SeO2 heterojunctions were characterized via X-ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy and X-ray photoelectron spectroscopy. It has revealed that, the thickness of outer Bi2SeO2 layer can be tuned upon the annealing temperatures, which strongly influenced the performance of catalyst towards water splitting performances. Annealed at 200 °C, the Bi2Se3/Bi2SeO2 heterojunction with ~5 nm of Bi2SeO2 layer yielded the highest hydrogen production rate of 136 μmol g?1 h?1. This enhanced photo-catalytic activity was ascribed to the synergy effect between the Bi2Se3/Bi2SeO2 layer, increased the visible light absorbance capacity, adjustment of the band gap and accelerate the electron-hole separation efficiency. The results represent a simply solution-based method towards a material with high photo-catalytic performance through the appropriate regulation of the oxidation degree of Bi2Se3 nanosheets, promising their industrial applications. 相似文献
12.
《International Journal of Hydrogen Energy》2019,44(60):31853-31859
Deposition of Pt NPs with preferred dispersion and morphologies on TiO2 have been the focus of studies in photocatalytic and photoelectrochemical hydrogen production. Green synthesis of TiO2/Pt NPs nanocomposites with narrow size distribution of Pt NPs still remain a challenge. Herein, we report that sucrose is highly efficient for the preparation of well-dispersed TiO2/Pt NPs photocatalysts. Moreover, the sucrose could act as an electron donor, showing higher hydrogen production activity under simulated sunlight than pure water. The as-synthesized photocatalysts have been characterized by techniques of transmission electron microscopy (TEM), energy dispersive X-ray spectrometer (EDX), and diffuse reflectance spectroscopy (DRS). Compared with TiO2/Pt NPs photocatalysts prepared through conventional photodeposition, the photocatalysts as prepared showed higher photocatalytic efficiency. Moreover, the catalyst could be reused easily without apparent degradation of their original photocatalytic activities. This approach presents a promising and low-cost strategy to improve the photocatalytic performance of TiO2 from biomass. 相似文献
13.
《International Journal of Hydrogen Energy》2019,44(31):16154-16163
Ceria dioxide supported on graphitic carbon nitride (CeO2/g-C3N4) composites were facilely synthesized to be application for photocatalytic hydrogen (H2) generation in this present work. The physical and chemical properties of CeO2/g-C3N4 nanocomposites were determined via a series of characterizations. The CeO2/g-C3N4 composites prepared by facile thermal annealing and rotation-evaporation method exhibit excellent photocatalytic H2 evolution with visible-light illumination. The best hydrogen generation rate of CeO2/g-C3N4 composite with 1.5 wt% Pt is 0.83 mmol h−1 g−1, which is almost same as that of composite with 3 wt% Pt prepared by simple physical mixing method. The significantly developed photocatalytic activity of CeO2/g-C3N4 composite is majorly ascribed to the stronger interfacial effects with the more visible-light absorbance and faster electron transfer. This work reveals that construction of the CeO2/g-C3N4 composite with high disperse and close knit by the facile thermal annealing and rotation-evaporation method could be an effective method to achieve excellent photocatalytic hydrogen evolution performance. 相似文献
14.
Sonam Patel Jiechao JiangFuqiang Liu 《International Journal of Hydrogen Energy》2011,36(17):11108-11115
We report a facile synthesis and characterization of highly-dispersed platinum nanoparticles supported on Ketjen carbon black (Pt/C) as electrocatalysts for polymer electrolyte membrane fuel fells (PEMFCs). Pt particles with size of ∼ 2.6 nm were synthesized through adsorption of Pt acetylacetonate on carbon supports and subsequently thermal decomposition. A comparative characterization analysis, including X-ray diffraction (XRD), high resolution transmission electron microscope (HR-TEM), cyclic voltammetry (CV), and hydrodynamic voltammetry measurements, was performed on the synthesized and commercial TKK catalysts. It revealed the details of Pt dispersion on the carbon support, particle size and distribution, electrochemical surface area (ECSA), and oxygen reduction reaction (ORR) activity of the catalysts. It was found that the synthesized Pt/C has similar particle size to that of the TKK catalyst (2.6 nm and 2.7 nm, respectively), but narrower particle size distribution. Accelerated durability tests under potential cycles were performed to study electrochemical degradation of the catalysts in corrosive environments. The synthesized Pt/C displayed significant losses in ECSA and activities after 20 k potential cycles, especially from 5 k to 20 k cycles, though with higher initial values (43% and 79% higher in ECSA and mass activity, respectively). 相似文献
15.
Development of heterostructured photocatalysts which can facilitate spatial separation of photo-generated charge carriers is crucial for achieving improved photocatalytic H2 production. Consequently, herein, we report the synthesis of Zn0.5Cd0.5S/Ni2P heterojunction photocatalysts with varying amount of Ni2P, 0.5 (S1), 1 (S2), 3 (S3), 5 (S4) and 10wt% (S5) for the efficient visible-light-assisted H2 generation by water splitting. The heterostructures were characterized thoroughly by PXRD, FE-SEM, EDS, HR-TEM and XPS studies. FE-SEM and HR-TEM analyses of the samples unveiled the presence of Zn0.5Cd0.5S microspheres composed of smaller nanocrystals with the surface of the microspheres covered with Ni2P nanosheets and the intimate contact between the Zn0.5Cd0.5S and the Ni2P. Further, visible-light-assisted photocatalytic investigation of the samples showed excellent water splitting activity of the heterostructure, Zn0.5Cd0.5S/1wt%Ni2P (S2) with very high H2 generation rate of 21.19 mmol h?1g?1 and the AQY of 21.16% at 450 nm with turnover number (TON) and turnover frequency (TOF) of 251,516 and 62,879 h?1 respectively. Interestingly, H2 generation activity of S2 was found to be about four times higher than that of pure Zn0.5Cd0.5S (5.0 mmol h?1g?1) and about 240 times higher than that of CdS/1wt%Ni2P. The enhanced H2 generation activity of S2 has been attributed to efficient spatial separation of photogenerated charge carriers and the presence of highly reactive Ni2P sites on the surface of Zn0.5Cd0.5S microspheres. A possible mechanism for the enhanced photocatalytic H2 generation activity of Zn0.5Cd0.5S/1wt%Ni2P (S2) has been proposed and is further supported by photoluminescence and photocurrent measurements. Furthermore, the catalyst, S2 can be recycled for several cycles without significant loss of catalytic activity and photostability. Remarkably, the H2 generation activity of S2 was found to be even higher than the reported examples of ZnxCd1-xS doped with noble metal cocatalysts. Hence, the present study highlights the importance of Zn0.5Cd0.5S/Ni2P heterostructures based on non-noble metal co-catalyst for efficient visible-light-driven H2 production from water splitting. 相似文献
16.
《International Journal of Hydrogen Energy》2019,44(36):19967-19977
A promising biochar/ZnFe2O4 (BZF) composite has been synthesized to improve the efficiency of visible-light-driven H2 evolution via a simple microwave hydrothermal method. The materials were investigated through diverse characterization means including XRD, FTIR, SEM, BET, XPS, VSM, UV–vis/DRS, PL, EIS. Different ratios of BZF composites expressed enhanced photocatalytic H2 evolution performance over pure ZnFe2O4. Especially, biochar/ZnFe2O4 catalysts with 5:1 mass ratio (BZF-5) attained the optimal H2 evolution rate, which is around 6 times higher than that of pure ZnFe2O4. Biochar acts as an electron mediator can effectively promote the separation of electron-hole pairs to enhance the rate of photocatalytic hydrogen evolution. Moreover, Eosin Y, photocatalyst and TEOA have synergistic effects accounted for enhanced photocatalytic performance in reaction system. Three cyclic runs for the photocatalytic H2 evolution on BZF-5 sample illustrated its good stability and sustainable reusability. 相似文献
17.
《International Journal of Hydrogen Energy》2022,47(85):36139-36148
Developing new renewable, carbon-neutral fuels to diminish the amount of released CO2 in the atmosphere and to solve global challenges such as global warming and climate change is significant. Among them, hydrogen (H2) is attracting much attention due to its high energy density, ease of transportation, and multiple means of production. To meet the global demand of H2, photocatalytic water splitting is one of the most promising methods for large scale production. Herein, Al-doped SrTiO3 photocatalyst (Al–SrTiO3) was prepared by a molten flux method. Then, plasmonic metal nanoparticles (Au, Cu, Pt), and cocatalysts Rh/Cr2O3 and CoOOH were selectively deposited onto the reductive and oxidative active sites of Al–SrTiO3 using multi-step photodeposition-impregnation methods for water splitting and H2 production under UV-rays, UV–Vis. Light, and visible light (λ ≥ 400 nm). Our results showed that, compared with Pt and Cu loaded Al–SrTiO3 photocatalyst supported with Rh/Cr2O3 and CoOOH cocatalysts, Au-loaded samples showed the highest H2 production efficiency under both UV (920 μmol/h - EQE = 41% at 365 nm) and UV–Vis (100.5 μmol/h) rays. In addition, the amount of evolved H2 decreased by increasing the weight ratio of Au nanoparticles (NPs) due to the overlap between Au NPs and Rh/Cr2O3 cocatalyst. Although Au 0.3 wt%-loaded sample showed high activity under both UV and UV–Vis. Rays, it exhibited almost no efficiency under visible light because of the large bandgap of Al–SrTiO3 (3.1 eV) and the poor absorption in the visible region. Visible light absorption was then enhanced by increasing the loaded amount of Au NPs and by separating Au NPs and Rh/Cr2O3 cocatalyst responsible for H2 evolution by combining both photodeposition and impregnation methods. Under visible light, Rh/Cr2O3-loaded Al–SrTiO3 with 4 wt % Au NPs showed the highest H2 evolution efficiency (41 μmol/3 h). This was attributed to the efficient hot electron transfer from Au NPs to Al–SrTiO3 then to RhCr2O3, resulting in charge separation needed for efficient H2 generation. 相似文献
18.
VS4/reduced graphene oxide (VS4/rGO) composites are successfully synthesized via a one-step hydrothermal route. Then their photocatalytic activities are examined by water splitting reaction, and the morphology and structure are characterized by transmission electron microscopy, X-ray diffraction, Fourier transform infrared, X-ray photoelectron spectroscopy and thermo gravimetric analysis, respectively. It is shown that graphene accelerates the nucleation during the growth period of VS4. Main product is VS4, not VS2. Monoclinic VS4 particles interact with graphene through chemical action. VS4/rGO composites show excellent photocatalytic water splitting activities under visible-light irradiation. This excellent performance is due to the formation of π-conjugated structure, which can transmit electrons from S2p to graphene rapidly. However, composites with excess graphene show poor dispersion, which leads to the best doping ratio of graphene is 5 wt%. 相似文献
19.
Warapong Krengvirat Srimala Sreekantan Ahmad-Fauzi Mohd Noor Nobuaki Negishi Song Yul Oh Go Kawamura Hiroyuki Muto Atsunori Matsuda 《International Journal of Hydrogen Energy》2012
Carbon-incorporated titanium dioxide (TiO2) photoelectrodes with different structural features were prepared via rapid-anodic oxidation under different electrical potentials and exposure times. The interstitial carbon arising from the pyrogenation of ethylene glycol electrolytes induced a new C2p occupied state at the bottom of the conduction band, which lowered the band gap energy to ∼2.3 eV and consequently enabled the visible-light responsiveness. Photoelectrodes with nanotubular structures provided higher photoconversion efficiency (η) and hydrogen (H2) evolution capability than those with irregular structures. The increased aspect ratio, wall thickness, and pore size of the nanotube arrays contributed to η through greater photon excitation and penetration. However, this contribution is limited by the high recombination of the charge carriers at ultra-high aspect ratios. Photoelectrodes with a nanotube length of ∼19.5 μm, pore size of ∼103 nm, wall thickness of ∼17 nm, and aspect ratio of ∼142.5 exhibited remarkable capability to generate H2 at an evolution rate of up to ∼508.3 μL min−1 cm−2 and η of ∼2.3%. 相似文献
20.
《International Journal of Hydrogen Energy》2017,42(27):16968-16978
A binary heterostructured CdS/MoS2 flowerlike composite photocatalysts was synthesized via a simple one-pot hydrothermal method. This photocatalyst demonstrated higher photocatalytic hydrogen production activity than pure MoS2. The heterojunction formed between MoS2 and CdS seems to promote interfacial charge transfer (IFCT), suppress the recombination of photogenerated electron–hole pairs, and enhance the hydrogen generation. Based on the good match between the conduction band (CB) edge of CdS and that of MoS2, electrons in the CB of CdS can be transferred to MoS2 easily through the heterojunction between them, which prevents the accumulation of electrons in the CB of CdS, inhibiting photocorrosion itself and greatly enhancing stability of catalyst. Hydrogen evolution reaction (HER) using Na2S/Na2SO3 or glucose as sacrificial agents in aqueous solution was investigated. The ratio between CdS and MoS2 plays an important role in the photocatalytic hydrogen generation. When the ratio between CdS and MoS2 reaches 40 wt%, the photocatalyst showed a superior H2 evolution rate of 55.0 mmol g−1 h−1 with glucose as sacrificial agent under visible light, which is 1.2 times higher than using Na2S/Na2SO3 as sacrificial agent. Our experimental results demonstrate that MoS2-based binary heterostructured composites are promising for photocorrosion inhibition and highly efficient H2 generation. 相似文献