Carbon nitride derived carbon and nitrogen Co-doped CdS for stable photocatalytic hydrogen evolution
TL;DR: In this paper, graphitic carbon nitride (GCN) is used as sacrifice agent to synthesize is nitrogen and carbon co-doped CdS nanoparticles with of uniform small size and higher specific surface area via hydrothermal reaction.
About: This article is published in Surfaces and Interfaces.The article was published on 2021-08-01. It has received 12 citations till now. The article focuses on the topics: Carbon nitride & Graphitic carbon nitride.
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TL;DR: Chalcogenides are narrow-band gap semiconductors that have been widely used as photocatalysts as mentioned in this paper, which allow more efficient absorption of over 40% of solar energy in the visible light range.
Abstract: Chalcogenides are narrow-band gap semiconductors that have been widely used as photocatalysts. These narrow-band gap materials allow more efficient absorption of over 40% of solar energy in the visible light range, which will eventually improve its photocatalytic properties. Under visible light irradiation, these materials generate electron and hole (e−/h+) pairs. Photo-generated e−/h+ pairs have been utilized to split water into hydrogen and oxygen and to remove and degrade industrial, pharmaceutical and agricultural organic/inorganic/biological pollutants that have been accumulated in the environment. In this perspective review, different types of chalcogenides, namely, binary, multinary (ternary and quaternary) and chalcogenide-based heterostructures are presented briefly. This perspective review also highlights the mechanisms involved and remarkable photocatalytic activity enhancement under visible light irradiation that has been widely researched such as the photocatalytic degradation of industrial pollutants and photocatalytic inactivation of bacteria. Lastly, future prospects for the use of chalcogenides as photocatalysts and chalcogenide-based heterostructures were discussed.
39 citations
TL;DR: In this paper, a hierarchical binary CdS/NiO hollow heterogeneous architectures (HHAs) with p-n heterojunction are constructed by a facile microwave-assisted wet chemical process for high-efficient photocatalytic hydrogen evolution reaction (HER) from water.
Abstract: The hierarchical binary CdS/NiO hollow heterogeneous architectures (HHAs) with p-n heterojunction are constructed by a facile microwave-assisted wet chemical process for high-efficient photocatalytic hydrogen evolution reaction (HER) from water. The asdesigned CdS/NiO HHAs are composed of hexagonal n-type CdS nanoparticles with a size in the range of 20–40 nm attaching to cubic p-type NiO hollow microspheres (HMSs) which are aggregates of porous nanoplates with a thickness of about 20 nm. The photocatalytic water splitting over CdS/NiO HHAs is significantly increased under simulated solar irradiation, among which the most active sample of CdS/NiO-3 (the mass ratio of CdS to NiO is 1:3) exhibits the fastest photocatalytic HER rate of 1.77 mmol·g−1·h−1, being 16.2 times than that of pure CdS. The boosted photocatalytic HER could be attributed to the synergistic effect on the proportional p-n heterojunction with special hierarchical hollow and porous morphology, an enhancement of visible light absorption, and an improvement of photoinduced charge separation as well as the photo-stability given by the composite heterojunction. This work shows a viable strategy to design the heterojunction with special morphology for the efficient hydrogen generation by water splitting utilizing solar energy.
24 citations
TL;DR: In this paper , the authors used the imidazolium salt zeolite framework (ZIFs) organometallic framework materials for preparing photocatalytic semiconductors and showed that the Co3O4 material obtained by this method not only has a unique spatial morphology but also shows a strong light absorption performance and a high charge transfer rate.
Abstract: The imidazolium salt zeolite framework (ZIFs) organometallic framework materials have the advantages of high stability and controllable structure and are excellent materials for preparing photocatalytic semiconductors. In this study, the regular dodecahedron material ZIF‐67 was used as the substrate, and the intermediate was calcined after the substrate adsorbed Co‐based metal clusters to obtain Co3O4 with a hollow double‐shell structure. Through SEM and fluorescence detection, it can be seen that the Co3O4 material obtained by this method not only has a unique spatial morphology but also shows a strong light absorption performance and a high charge transfer rate. In addition, graphite‐like phase carbon nitride (g‐C3N4), as a traditional catalyst, has been unable to move toward industrialization due to its low electron utilization and light absorption properties. So here, the composite catalyst CNCO‐x (x = 1, 2, 2, 3, 4, and 5) was prepared by simply anchoring Co3O4 and g‐C3N4 to improve the catalytic performance of g‐C3N4. The results show that the introduction of Co3O4 not only improves the electron utilization of g‐C3N4 but forms a charge transfer bridge channel (p‐n heterojunction) after contact between the two, which effectively promotes the rapid transfer of photoelectrons between the contact interfaces. Finally, when the amount of Co3O4 introduced is 15%, the amount of hydrogen produced in 5 hours can reach 0.163 mmol (3.26 mmol g−1 hour−1), which is 163 times that of pure g‐C3N4.
8 citations
TL;DR: In this paper , the Co3O4/ZnIn2S4 p−n heterojunction photocatalyst was successfully prepared using the block stacked by Co 3O4 nanosheets as the carrier.
Abstract: The Co3O4/ZnIn2S4 p‐n heterojunction photocatalyst was successfully prepared using the block stacked by Co3O4 nanosheets as the carrier. Because the surface of the Co3O4 nano‐block is rough, it is easy to absorb more ZnIn2S4 nanosheets, which leads to the tight coupling of composite Co3O4/ZnIn2S4. In addition, the interaction of the p‐n heterojunction interface accelerates the separation of photogenerated carriers, thus increasing the rate of photocatalytic hydrogen evolution. In the photocatalytic hydrogen evolution test, the composite Co3O4/ZnIn2S4 showed excellent hydrogen evolution performance, and the maximum hydrogen evolution capacity was up to 72.01 μmol, which was about 5.6 times that of pure Co3O4. Under the action of the built‐in electric field, the accumulation of electrons and holes in the ZnIn2S4 conduction band and Co3O4 valence band is accelerated, thus higher separation efficiency is achieved. The addition of various characterizations also confirmed the excellent properties of the composites. This work provides a reference for the construction of photocatalytic heterojunction.
7 citations
TL;DR: In this paper , the Co3O4/ZnIn2S4 p-n heterojunction photocatalyst was successfully prepared using the block stacked by Co3 o4 nanosheets as the carrier.
Abstract: The Co3O4/ZnIn2S4 p-n heterojunction photocatalyst was successfully prepared using the block stacked by Co3O4 nanosheets as the carrier. Because the surface of the Co3O4 nano-block is rough, it is easy to absorb more ZnIn2S4 nanosheets, which leads to the tight coupling of composite Co3O4/ZnIn2S4. In addition, the interaction of the p-n heterojunction interface accelerates the separation of photogenerated carriers, thus increasing the rate of photocatalytic hydrogen evolution. In the photocatalytic hydrogen evolution test, the composite Co3O4/ZnIn2S4 showed excellent hydrogen evolution performance, and the maximum hydrogen evolution capacity was up to 72.01 μmol, which was about 5.6 times that of pure Co3O4. Under the action of the built-in electric field, the accumulation of electrons and holes in the ZnIn2S4 conduction band and Co3O4 valence band is accelerated, thus higher separation efficiency is achieved. The addition of various characterizations also confirmed the excellent properties of the composites. This work provides a reference for the construction of photocatalytic heterojunction.
6 citations
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TL;DR: In this article, a critical review presents the recent advances and progress in the design and synthesis of various semiconductor photocatalytic technology that converts solar energy into chemical fuel has been widely studied.
Abstract: To solve the problem of the global energy shortage and the pollution of the environment, in recent years, semiconductor photocatalytic technology that converts solar energy into chemical fuel has been widely studied. Regarding semiconductor-based photocatalysts, CdS has attracted extensive attention due to its relatively narrow bandgap for visible-light response and sufficiently negative potential of the conduction band edge for the reduction of protons. Studies have shown that CdS-based photocatalysts possess excellent photocatalytic performance in terms of solar-fuel generation and environmental purification. This critical review presents the recent advances and progress in the design and synthesis of various CdS and CdS-based photocatalysts. The basic physical and chemical properties of CdS and the related growth mechanism have been briefly summarized. Moreover, the applications of CdS-based photocatalysts have been discussed such as in photocatalytic hydrogen production, reduction of CO2 to hydrocarbon fuels and degradation of pollutants. Finally, a brief perspective on the challenges and future directions for the development of CdS and CdS-based photocatalysts are also presented.
1,054 citations
TL;DR: In this paper, Zhao et al. used Zn11−xCdxS solid solutions as the visible-light-driven photocatalysts and a mixed Na2S and Na2SO3 aqueous solution as the sacrificial reagent.
Abstract: Photocatalytic hydrogen (H2) production from water splitting under visible-light irradiation is considered to be an attractive way to solve the increasing global energy crises in modern life. In this study, highly efficient photocatalytic H2 production without the assistant of a cocatalyst was achieved using Zn11–xCdxS solid solutions as the visible-light-driven photocatalysts and a mixed Na2S and Na2SO3 aqueous solution as the sacrificial reagent. The Zn1–xCdxS samples were prepared by a simple zinc–cadmium–thiourea (Zn–Cd–Tu) complex thermolysis method using thiourea, zinc acetate (Zn(Ac)2), and cadmium acetate (Cd(Ac)2) as the precursors. The obtained Zn1–xCdxS solid solutions feature a small crystallite size and precisely controllable band structure, which are beneficial for the photocatalysis. When the Zn/Cd molar ratio is 1:1, the prepared Zn0.5Cd0.5S sample exhibits the highest H2-production rate of 7.42 mmol·h–1·g–1, exceeding that of the pure CdS and ZnS samples by more than 24 and 54 times, resp...
508 citations
TL;DR: Through interstitial P doping, the impurity level of S vacancies is located near the Fermi level and becomes an effective electron trap level in CdS-P, which can change dynamic properties of photogenerated electrons and thus prolong their lifetimes.
Abstract: Photocatalytic hydrogen evolution from pure water is successfully realized by using interstitial P-doped CdS with rich S vacancies (CdS-P) as the photocatalyst in the absence of any electron sacrificial agents. Through interstitial P doping, the impurity level of S vacancies is located near the Fermi level and becomes an effective electron trap level in CdS-P, which can change dynamic properties of photogenerated electrons and thus prolong their lifetimes. The long-lived photogenerated electrons are able to reach the surface active sites to initiate an efficient photocatalytic redox reaction. Moreover, the photocatalytic activity of CdS-P can be further improved through the loading of CoP as a cocatalyst.
407 citations
TL;DR: It is demonstrated that ZnIn2S4/g-C3N4 heterojunction nanosheets considerable boost the charge transfer efficiency, therefore improve the probability of photoinduced charge carriers to reach the photocatalysts surfaces for highly efficient H2 production.
Abstract: We have realized in-situ growth of ultrathin ZnIn2S4 nanosheets on the sheet-like g-C3N4 surfaces to construct a "sheet-on-sheet" hierarchical heterostructure. The as-synthesized ZnIn2S4/g-C3N4 heterojunction nanosheets exhibit remarkably enhancement on the photocatalytic activity for H2 production. This enhanced photoactivity is mainly attributed to the efficient interfacial transfer of photoinduced electrons and holes from g-C3N4 to ZnIn2S4 nanosheets, resulting in the decreased charge recombination on g-C3N4 nanosheets and the increased amount of photoinduced charge carriers in ZnIn2S4 nanosheets. Meanwhile, the increased surface-active-sites and extended light absorption of g-C3N4 nanosheets after the decoration of ZnIn2S4 nanosheets may also play a certain role for the enhancement of photocatalytic activity. Further investigations by the surface photovoltage spectroscopy and transient photoluminescence spectroscopy demonstrate that ZnIn2S4/g-C3N4 heterojunction nanosheets considerable boost the charge transfer efficiency, therefore improve the probability of photoinduced charge carriers to reach the photocatalysts surfaces for highly efficient H2 production.
308 citations
TL;DR: In this paper, NiCo-LDH/P-CdS hybrid photocatalysts are fabricated by combining strategies of P-doping and in-situ loading of NiCoLDH.
Abstract: Designing durable and highly active photocatalysts for hydrogen evolution via water splitting is still very challenging. Novel NiCo-LDH/P-CdS hybrid photocatalysts are fabricated by combining strategies of P-doping and in-situ loading of NiCo-LDH. P-doping creates a mid-gap at the bottom of the conduction band of CdS, which facilitates to prolong the life-time of the photo-induced electrons. Subsequently, the in-situ loading of NiCo-LDH is able to form heterojunctions between NiCo-LDH and P-CdS that not only promote the separation efficiency of carriers, but also effectively reduce the light corrosion phenomenon commonly observed in CdS. The as-prepared 2 mol% NiCo-LDH/40 wt% P-CdS sample shows a high visible-light catalytic H2 production rate of 8.665 mmol·h−1 g−1, which is 45 times higher than pure CdS. The apparent quantum yield is determined to be 14.0% at 420 nm monochromatic light. Based on the calculation of density function theory (DFT), the rational photocatalytic mechanism has been proposed and is well consistent with the experimental results. Our study not only demonstrates a facile, eco-friendly and scalable strategy to synthesize highly efficient photocatalysts, but also provides a new viewpoint of the rational design and synthesis of advanced photocatalysts by harnessing the strong synergistic effects through simultaneously tuning and optimizing the electronic structure and surface.
196 citations