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1.
《International Journal of Hydrogen Energy》2020,45(15):8497-8506
A facile, one-pot, solvothermal synthesis of MoS2 microflowers (S1) and the heterostructures MoS2/g-C3N4 with varying ratios of 1:1 (S2), 1:2 (S3) and 1:3 (S4) exhibiting enhanced visible-light-assisted H2 generation by water splitting has been reported. The compounds were thoroughly characterized by PXRD, FESEM, HRTEM, EDS, UV–vis and XPS techniques. FESEM and HRTEM analyses showed the presence of microflowers composed of nano-sized petals in case of pure MoS2 (S1), while the MoS2 microflowers covered with g-C3N4 nanosheets in case of MoS2/g-C3N4 heterostructure, S4. XPS analysis of S2 showed the presence of 2H phase of MoS2 with g-C3N4. The Eosin-Y/dye-sensitized visible-light-assisted photocatalytic investigation of the samples in the absence of any noble metal co-catalyst revealed very good water splitting activity of MoS2/g-C3N4 heterostructure, S2 with hydrogen generation rate of 1787 μmol h−1g−1 which is about 6 and 40 times higher than pure MoS2 and g-C3N4 respectively. The relatively higher catalytic activity of the heterostructure, S2 has been ascribed to the efficient spatial separation of photo-induced charge carriers owing to the synergistic interaction between MoS2 and g-C3N4. A possible mechanism for the Eosin-Y-sensitized photocatalytic H2 generation activity of MoS2/g-C3N4 heterostructures has also been presented. The enhanced activity of S2 was further supported by fluorescence measurements. Thus, the present study highlights the importance of non-noble metal based MoS2/g-C3N4 heterojunction photocatalysts for efficient visible-light-driven H2 production from water splitting. 相似文献
2.
Enzhou Liu Chenyang Jin Chenhui Xu Jun Fan Xiaoyun Hu 《International Journal of Hydrogen Energy》2018,43(46):21355-21364
Transition metal phosphides are considered as the most prospective replacements for noble metal cocatalysts used for H2 evolution during photocatalytic water splitting. In this work, Ni2P/g-C3N4 composite photocatalyst was synthesized using a simple in-situ hydrothermal method by one step. Benefiting from the excellent light trapping, efficient transfer of charge carriers and strong stability of Ni2P nanoparticles, as well as the stable interface contact between Ni2P and g-C3N4, the Ni2P/g-C3N4 exhibit greatly enhanced H2 evolution performance during photocatalytic water splitting. The optimized H2 evolution rate can reach 3344 μmol h?1 g?1 over 17.5 wt% Ni2P/g-C3N4, which is 68.2 times greater than that of pure g-C3N4 and even much greater than that of 15 wt% Pt/g-C3N4. The apparent quantum efficiency (QE) is about 9.1% under 420 nm monochromatic. The enhancement mechanism was demonstrated in detail by transient photocurrent responses, photoluminescence spectra and electrochemical impedance spectroscopy. This work develops a facile strategy to fabricate transition metal phosphide/semiconductor heterojunction systems with potential application for photocatalytic H2 evolution. 相似文献
3.
Nanoporous Zn0.5Cd0.5S nanosheets/reduced graphene oxide (Zn0.5Cd0.5S/RGO) composites were prepared by a facile in-situ photoreduction method of graphene oxide (GO) in the presence of nanoporous Zn0.5Cd0.5S single-crystal-like nanosheets under visible light irradiation. The Zn0.5Cd0.5S/RGO photoelectrodes was characterized by TEM, IR and Raman spectra. Electrochemical measurements demonstrated that Zn0.5Cd0.5S/RGO photoelectrodes own a higher anodic photocurrent density, a lower zero current potential, and a higher photoelectrochemical response than that of pure Zn0.5Cd0.5S photoelectrodes under visible light irradiation under the same conditions. This high photochemical activity is predominately ascribed to the presence of RGO, which serves as the electron collector to efficiently prolong the lifetime of photoinduced electrons from the excited Zn0.5Cd0.5S nanosheets. In addition, the content of RGO in the composites had a remarkable influence on the photoelectrochemical behaviors of the photoelectrodes and the optimal RGO content was found to be 5 wt%. Zn0.5Cd0.5S/RGO composites at RGO content of 5 wt% reached a stable hydrogen production rate of 12.05 μmol h−1 cm−2 at an externally applied bias of 0.6 V. Furthermore, the Zn0.5Cd0.5S/RGO composites as photoelectrodes were found to be highly stable for hydrogen evolution reaction. The electrons stored in RGO are readily discharged or scavenged on demand by the applied positive bias to the counter electrode, and thus rectify the flow of electrons. Importantly, this work may open up a facile in-situ method for using RGO scaffold to create a stable photoelectrode with enhanced photoelectrochemical activities. 相似文献
4.
Teng Li Xin Guo Lijun Zhang Teng Yan Zhiliang Jin 《International Journal of Hydrogen Energy》2021,46(39):20560-20572
For heterojunction composite photocatalyst, intimate contact interface is the key to the carrier transfer separation conditions. Due to the interface contact, the electron transfer rate between catalysts can be increased during photocatalytic hydrogen production, therefore, we design the close contact of 0D/2D heterojunction, which greatly enhanced the photocatalytic hydrogen production activity of the composite catalyst. The composite catalyst WO3/CoP was obtained by simple high temperature in situ synthesis. Moreover, it was proved by photoelectric chemistry and fluorescence tests that appropriate conduction band and valence band locations of WO3 and CoP provided a favorable way for thermodynamic electron transfer. In addition, fluorescence results showed that WO3 load effectively promoted photoelectron-hole transfer and increased electron lifetime. The formation of S-scheme heterojunctions can make more efficient use of useful photogenerated electrons and prevent the photogenerated electron-hole recombination of CoP itself, further promote the liveness of photocatalytic H2 evolution. Meanwhile, the study of Metal-organic frameworks (MOFs) materials further promoted the application of MOFs derivatives in the field of photocatalytic hydrogen evolution, and provided a reference for the rational design of composite catalysts for transition metal phosphide photocatalysts. 相似文献
5.
《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
6.
《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
7.
Yanming Lin Qi Wang Mintong Ma Peiying Li V. Maheskumar Zhenyi Jiang Ruiqin Zhang 《International Journal of Hydrogen Energy》2021,46(14):9417-9432
Our theoretical research indicate that the electric field are generated in the direction of (C doped) TiO2 (101) surface to (B-doped) g-C3N4 monolayer for the pristine, C and B doped g-C3N4/TiO2, and higher band-edge potential on the (C doped) TiO2 (101) surface are observed compared to (B-doped) g-C3N4 monolayer. Thus, the pristine (2.591 eV), C-doped (2.663 eV) and B-doped (2.339 eV) g-C3N4/TiO2 are Z-scheme heterostructures, which promotes charge separation and retains a prominent redox ability. After C doping, the C 2p energy level is introduced which facilitate the separation of photoexcited carriers. The B-doped g-C3N4/TiO2 has a reduced bandgap and the mixing of B 2p and N 2p energy levels, promoting the red-shift of the optical absorption edge. The C&B codoped g-C3N4/TiO2 follows type-II charge transfer mode because of their synergistic effect in C and B atoms, which changes the direction of the built-in electric field. It also has a narrow bandgap (1.309 eV) and effectively separate electron-hole pairs leading to strong optical absorption ability in the range of 360 nm–460 nm. The band-edges matching of the semiconductor photocatalyst and the direction of the built-in electric field jointly determine whether the charges are selected to be Z-scheme or II-type transfer mode. Based on g-C3N4/TiO2 for C or/and B (co)doping, their different charge transfer modes have been established and they are expected to show promising photocatalytic water splitting performance. 相似文献
8.
Shaoqin Peng Ran An Yuexiang Li Gongxuan Lu Shuben Li 《International Journal of Hydrogen Energy》2012
Bi3+ doped Cd0.5Zn0.5S photocatalysts were prepared by a simple hydrothermal method, and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscope (XPS), energy dispersive X-ray spectroscopy (EDX), BET and UV-Vis absorption spectroscope techniques. When Bi3+ doping content is lower, the doping ions lie at the surface lattice sites, whereas when the doping content is higher, the ions also enter the bulk lattice sites. Their photoactivities were evaluated by hydrogen evolution from aqueous solution containing Na2S and Na2SO3 as a hole scavenger under visible light (λ ≥ 420 nm) irradiation. Bi3+ doping enhances markedly photocatalytic activity. When Bi3+ doping content is 0.10 mole %, the photocatalyst exhibits the highest activity, and the average apparent quantum yield amounts to 9.71% during 30 h irradiation. The possible mechanism was discussed. 相似文献
9.
Issei Fujimoto Nini Wang Rie Saito Yugo Miseki Takahiro Gunji Kazuhiro Sayama 《International Journal of Hydrogen Energy》2014
We report on the improvement in the water splitting efficiency of a WO3/BiVO4 composite photoelectrode by the application of an improved auto-combustion method to the preparation of porous BiVO4 thin films. The unique feature of this preparation method is the addition of both NH4NO3, as a strong oxidizing agent, and an organic additive into BiVO4 precursor solution. The local decomposition heat of the organic additive and oxidizing agent created a porous film with small, highly crystalline BiVO4 particles. The photoelectrode has many advantages over existing ones, such as the high light-harvesting efficiency (LHE), a single BiVO4 phase, the facile access of the holes to the photoelectrode/electrolyte interface, and the ease of water and oxygen diffusion. The maximum incident photon-to-current efficiency (IPCE) was estimated to be 64% (at 440 nm, 1.23 V vs. RHE) and the applied bias photon-tocurrent efficiency (ABPE) reached as high as 1.28%. This ABPE value is highest among all oxide semiconductor photoelectrodes reported previously, except for the case of a stacking photoelectrode system. 相似文献
10.
Highly ordered TiO2 nanotube arrays for hydrogen production have been synthesized by electrochemical anodization of titanium sheets. Under solar light irradiation, hydrogen generation by photocatalytic water splitting was carried out in the two-compartment photoelectrochemical cell without any external applied voltage. The hydrogen gas and oxygen generated on Pt side and on TiO2 nanotubes side respectively were efficiently separated. The effect of anodization time on the morphology structures, photoelectrochemical properties and hydrogen production was systematically investigated. Due to more charge carrier generation and faster charge transfer, a maximum photoconversion efficiency of 4.13% and highest hydrogen production rate of 97 μmol h−1cm−2 (2.32 mL h−1cm−2) were obtained from TiO2 nanotubes anodized for 60 min. 相似文献
11.
Ziwei Pan Rui Wang Junnan Li Shahid Iqbal Wei Liu Kebin Zhou 《International Journal of Hydrogen Energy》2018,43(10):5337-5345
Design of non-noble-metal artificial photosynthesis system that can split water with high apparent quantum yield (AQY) and robust stability remains a fundamental challenge. Here we report that a physical mixture of Fe2P nanopaticles (NPs) and CdS nanosheets (NSs) can gives AQY of photocatalytic hydrogen production as high as 90% at 420 nm monochromatic light with ethanol as electron donor at strong alkaline conditions. The highest rate for hydrogen production reached about 220 mmol g?1 h?1. In this hybrid photocatalyst system, free standing Fe2P NPs act as efficient and robust noble-metal-free co-catalysts and ultrathin CdS NSs are used as the photosensitizer. PL and TRPL results demonstrate that photoexcited electron can transfer from the conduction band of the excited CdS to Fe2P, which aided charge separation and enhanced the hydrogen evolution activity. Femtosecond transient absorption result reveals that the time-averaged interfacial electron transfer (ET) rate constant (<kET>) from CdS NSs to Fe2P is about 7.4 × 109 s?1 under the guarantee of the scavenging of photoexcited hole immediately, which is one order faster than the electron relaxation rate in pure CdS NSs. 相似文献
12.
《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
13.
《International Journal of Hydrogen Energy》2023,48(52):19995-20005
Hydrogen production from electrochemical water splitting is a promising strategy to generating green energy, which requires development of efficient and stable bifunctional catalysts for hydrogen and oxygen evolution reaction (HER/OER). Herein, dual transition metal phosphides/N-doped carbon/Nickel foam composite (CoNiP/NC-NF) is prepared via direct phosphidation of ZIF-67, in which ZIF-67 can control the size and N-doping content of CoNiP/NC, boosting the bifunctional activities for the OER and HER. Then, the overall water splitting is performed by using CoNiP/NC-NF as the cathode and anode, showing a low cell voltage of 1.60 V to reach current density of 10 mA cm−2. Experimental studies indicate that ZIF-67 influences the electrocatalytic performance, and theoretical studies identify the active component of CoNiP/NC-NF for HER and OER, respectively. 相似文献
14.
Xiang Feng Yuhai Zhao Dakuo Liu Yasi Mo Yibin Liu Xiaobo Chen Wenjuan Yan Xin Jin Bingxu Chen Xuezhi Duan De Chen Chaohe Yang 《International Journal of Hydrogen Energy》2018,43(36):17112-17120
Catalytic hydrolysis of ammonia borane has tremendous potential as an energy-efficient approach to supply hydrogen for energy vehicles and portable electronic devices. Herein, DFT calculation is first performed on electronic properties of Ni2P and Ni5P4 nanocatalysts. It is found that more electrons are transferred from Ni to P for Ni5P4, indicating that Ni5P4 may show superior performance based on the electron effect. Therefore, Ni2P and Ni5P4 with high purity are synthesized by the phase-controlled thermal decomposition approach. Gratifyingly, the Ni5P4 catalyst exhibits the as-expected better catalytic activity than that of Ni2P catalyst. It also shows low activation energy and good stability. Furthermore, the structures and morphologies of both catalysts are characterized by multi-techniques such as XRD, HRTEM and XPS. The better performance could be ascribed to the higher positive charge of Ni together with the stronger ensemble effect of P. The insights sheds new light on the design of efficient NiP catalysts for hydrogen generation. 相似文献
15.
Xiao-jing Wang Xu-li Li Chao Liu Fa-tang Li Yu-pei Li Jun Zhao Rui-hong Liu Guo-dong Li 《International Journal of Hydrogen Energy》2018,43(1):219-228
The development of high-efficiency and low-cost photocatalysts in photocatalytic H2 evolution systems from water remains challenging. The substitution of a noble metal as the co-catalyst is still one of the important and meaningful issues in this field. Herein, we report a series of CaIn2S4 catalysts combined with Ni2P, which acts as the co-catalyst, for boosting photocatalytic hydrogen evolution under visible light. The integrated system of the Ni2P/CaIn2S4 composite exhibited high efficiency and durability, which were even higher than those of Pt decorated catalysts. The promoting effect of Ni2P can be ascribed to its excellent reductive ability and analogous metallic character, which can accelerate the transfer and consumption of the photo-generated electrons. Moreover, based on the surface photo-voltage technique and electrochemical tests, the unique mechanism of Ni2P for the movement of photo-generated charges during the photocatalysis process is proposed for the first time. 相似文献
16.
Lisha Yan Jun Zhang Xuemei Zhou Xiaoxing Wu Jinyao Lan Yinshu Wang Gang Liu Jiaguo Yu Linjie Zhi 《International Journal of Hydrogen Energy》2013
Potassium niobate (KNbO3) submicro-crystals with cubic and orthorhombic phases were hydrothermally prepared and characterized by powder X-ray diffraction, micro-Raman spectroscopy, Fourier transform infrared spectroscopy, nitrogen adsorption–desorption, diffuse reflectance UV–visible spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and high-resolution transmission electron microscopy. The photocatalytic performance of the as-prepared KNbO3 samples was evaluated toward H2 generation from an aqueous methanol solution under UV. The surface area-normalized rate of H2 production over submicro-cubes with cubic phase is two times larger than that of submicro-rods with orthorhombic phase. In addition, both cubic and orthorhombic KNbO3 submicro-crystals showed much higher reactivity than commercial KNbO3 bulk-like powders. The underlying mechanism was discussed in terms of crystal structure and electronic structure. The results from this study are potentially applicable to a range of perovskites useful in water splitting as well as other areas of heterogeneous photocatalysis. 相似文献
17.
Cong Wang Zhili Wang Hongli Wang Yue Chi Minggang Wang Daowen Cheng Jingjing Zhang Chen Wu Zhankui Zhao 《International Journal of Hydrogen Energy》2021,46(13):9030-9039
Developing an efficient catalyst for hydrogen (H2) generation from hydrolysis of ammonia borane (AB) to significantly improve the activity for the hydrogen generation from AB is important for its practical application. Herein, we report a novel hybrid nanostructure composed of uniformly dispersed Co@Co2P core-shell nanoparticles (NPs) embedded in N-doped carbon nanotube polyhedron (Co@Co2P/N–CNP) through a carbonization-phosphidation strategy derived from ZIF-67. Benefiting from the electronic effect of P doping, high dispersibility and strong interfacial interaction between Co@Co2P and N-CNTs, the Co@Co2P/N–CNP catalyst exhibits excellent catalytic performance towards the hydrolysis of AB for hydrogen generation, affording a high TOF value of 18.4 mol H2 mol metal?1 min?1 at the first cycle. This work provides a promising lead for the design of efficient heterogeneous catalysts towards convenient H2 generation from hydrogen-rich substrates in the close future. 相似文献
18.
《International Journal of Hydrogen Energy》2022,47(5):2936-2946
A high-efficiency and easy-available approach was developed to obtain a ternary heterojunction composites with advanced hydrogen evolution reaction (HER) performance under visible light by water split. PdAg bimetallic nanoparticles make a close contact interface between g-C3N4(CN) and Zn0.5Cd0.5S(ZCS). Under visible light irradiation, CN and ZCS are both excited to generate electron-hole pairs, PdAg bimetallic nanoparticles act as a bridge between CN and ZCS. Not only can the photogenerated electrons from CN be captured, but they can also be quickly transferred to the surface of ZCS and participate in the photocatalytic reaction to release H2, and the recombination of charge carriers between the contact interface of ZCS and CN can be significantly inhibited. In addition, the thin CN layer reduces the photocorrosion of the ZCS and enhances the specific surface area of the composite material. After testing, the composite material with 30 wt% ZCS and 4 wt% PdAg demonstrates hydrogen evolution performance, up to 6250.7 μmol g?1h?1, which is 753 times the hydrogen evolution rate of single-component CN and 12.6 times of ZCS/CN. Compared with single-component and two-component photocatalysts, the ternary ZCS/PdAg/CN photocatalyst achieves significantly enhanced photocatalytic activity. 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.
Chao-Wei Huang Chi-Hung Liao Jeffrey C.S. Wu Yu-Chang Liu Chun-Ling Chang Chih-Hung Wu Masakazu Anpo Masaya Matsuoka Masato Takeuchi 《International Journal of Hydrogen Energy》2010
Photocatalytic TiO2 thin films were prepared via an electron beam-induced deposition (EBID) method. The effects of post-calcination treatment on the properties of the prepared TiO2 thin films were studied. X-ray diffraction (XRD), scanning electron microscope-energy dispersive spectrometry (SEM-EDS), and UV–V is absorption spectrometry were performed to reveal the crystallinity, surface morphology, chemical composition, and light absorbance of the prepared TiO2 thin films. The photoelectrochemical characteristics of the TiO2 thin films were investigated with a potentiostat. Under UV irradiation, a photocurrent of ˜2.1 mA was observed for the TiO2 thin film with post-calcination at 500 °C. A water-splitting reaction was conducted over the TiO2 thin film with the best photoelectrochemical performance. The yields of hydrogen and oxygen were 59.8 and 30.6 μmole, respectively, after 8 h of reaction under UV irradiation. 相似文献