scispace - formally typeset
Search or ask a question
Journal ArticleDOI

Facile fabrication of CdS/UiO-66-NH2 heterojunction photocatalysts for efficient and stable photodegradation of pollution

TL;DR: In this article, a novel CdS/UiO-66-NH2 heterojunction photocatalyst has been successfully fabricated via facile water bath deposition, which introduces deionized water as solvent, reduces production cost and simplifies the fabrication process.
Abstract: Novel CdS/UiO-66-NH2 heterojunction photocatalysts have been successfully fabricated via facile water bath deposition. Compared with the traditional preparation technology, such strategy introduces deionized water as solvent, reduces production cost and simplifies the fabrication process of the heterojunction photocatalyst. Characterizations indicate that CdS nanoparticles (NPs) are uniformly interspersed on the surface of UiO-66-NH2 and the intimate contacted heterojunction interface is generated to prevent recombination of photogenerated charge carriers. CdS/UiO-66-NH2 with a mass ratio of 1.5:1 (CdS: UiO-66-NH2) exhibits the highest photocatalytic degradation rate for RhB of approximately 92.5% in 40 min and excellent photostability through four recycles. Furthermore, Photoluminescence (PL) spectra, UV–vis diffuse reflectance spectra (DRS), transient photocurrent, electrochemical impedance spectra (EIS), Nyquist plots and Mott-Schottky plots are applied to characterize the photoelectrochemical properties. The observably enhanced photocatalytic performance can be attributed to: 1) larger specific surface area, increased photocatalytic active sites, intimate contacted interface, 2) created n-n type heterojunction, and 3) rapid separation and transfer of photoexcited interfacial charges.
Citations
More filters
Journal ArticleDOI
TL;DR: This review highlights the advances in the use of MOFs in the elimination (adsorption and/or degradation) of EOCs from water, classifying them by the nature of the contaminant.
Abstract: Water is essential in all aspects of life, being the defining characteristic of our planet and even our body. Regrettably, water pollution is increasingly becoming a challenge due to novel anthropogenic pollutants. Of particular concern are emerging organic contaminants (EOCs), the term used not only to cover newly developed compounds but also compounds newly discovered as contaminants in the environment. Aside from anthropogenic contamination, higher temperature and more extreme and less predictable weather conditions are projected to affect water availability and distribution. Therefore, wastewater treatment has to become a valuable water resource and its reuse is an important issue that must be carried out efficiently. Among the novel technologies considered in water remediation processes, metal-organic frameworks (MOFs) are regarded as promising materials for the elimination of EOCs since they present many properties that commend them in water treatment: large surface area, easy functionalizable cavities, some are stable in water, and synthesized at large scale, etc. This review highlights the advances in the use of MOFs in the elimination (adsorption and/or degradation) of EOCs from water, classifying them by the nature of the contaminant.

542 citations

Journal ArticleDOI
TL;DR: In this article, the progress in the design and synthesis of various metal sulfide/MOF-based nanocomposites for applications in photocatalytic H2 production is provided.

149 citations

Journal ArticleDOI
TL;DR: In this paper, a review of the latest efforts in applying UiO-66 MOFs as superior water-stable MOFs for efficient removal (adsorption/separation and degradation/reduction) of various water pollutants, including organic dyes, heavy metal ions, pharmaceuticals and personal care products, phosphate, and fluoride.

78 citations

Journal ArticleDOI
TL;DR: Zirconium-based metal organic frameworks (Zr-MOFs) materials have gathered increasing interest in the field of photocatalysis as discussed by the authors, and they not only have the large surface area, orderly porous structure, and tunable organic bridging linker/metal clusters as other MOFs, but also possess higher thermal stability and excellent water-tolerant than most of other materials.

76 citations

Journal ArticleDOI
TL;DR: An efficient and recyclable CdS/SnO2 heterostructure was synthesized for photocatalytic degradation of methylene blue dye under UV and natural sunlight radiations as discussed by the authors.
Abstract: An efficient and recyclable CdS/SnO2 heterostructure containing various proportions of CdS (0–10) wt % was synthesized for photocatalytic degradation of methylene blue dye under UV and natural sunlight radiations. Mesoporous SnO2 nanoparticles of surface area 19.2 m2/g and particle size 34 nm with well definite slit pore structure were synthesized by sol-gel route using span as structure and pore directing agent. The physicochemical properties of the novel nanoparticles were investigated by X-ray diffraction [XRD], N2-adsorption-desorption isotherm, diffuse reflectance spectra [DRS], X-ray photoelectron spectroscopy [XPS], photoluminescence [PL] and high resolution transmission electron microscope [HRTEM]. CdS quantum dots of size 9 nm, surface area 26.5 m2/g and wide mesoporous size (pore radius = 119.2 A) were incorporated homogeneously on the surface of SnO2 forming an efficient heterojunction that cause a remarkable reduction in the band gap energy of SnO2 from 3.52 to 2.53 eV. These novel heterostructures facilitate the electron transfer from CB of CdS of more negative potential (-0.52 eV) to that of SnO2 of less negative potential (-0.04 eV), thus enhancing the separation efficiency of the charge carrier and increasing the life time of the reactive radicals. It is emphasized that the photocatalytic reactivity of SnCd5 is more than twice that of SnO2 and CdS nanoparticles. Experiments with different quenchers indicate that the electrons conduction band and superoxide radicals are the predominant reactive species on SnCd5 hybrid nanoparticles, however, hydroxyl radical and positive holes are more efficient on pure SnO2 surface. The as-synthesized SnCd5 nanoparticles exhibits an excellent photocatalytic stability and the catalyst retains 83 % of its reactivity after five consecutive cycles revealing that there is no deterioration in the catalyst structure.

70 citations

References
More filters
01 Jan 2008
TL;DR: A review of the current progress in the area of TiO 2 photocatalysis, mainly photocatalytic air purification, sterilization and cancer therapy is discussed in this article.
Abstract: Abstract Scientific studies on photocatalysis started about two and a half decades ago. Titanium dioxide (TiO 2 ), which is one of the most basic materials in our daily life, has emerged as an excellent photocatalyst material for environmental purification. In this review, current progress in the area of TiO 2 photocatalysis, mainly photocatalytic air purification, sterilization and cancer therapy are discussed together with some fundamental aspects. A novel photoinduced superhydrophilic phenomenon involving TiO 2 and its applications are presented.

6,294 citations

Journal ArticleDOI
TL;DR: This review attempts to summarize the recent progress in the rational design and fabrication ofheterojunction photocatalysts, such as the semiconductor-semiconductor heterojunction, the semiconductors-metal heterojunctions, the silicon-carbon heteroj junction and the multicomponent heteroj conjunction.
Abstract: Semiconductor-mediated photocatalysis has received tremendous attention as it holds great promise to address the worldwide energy and environmental issues. To overcome the serious drawbacks of fast charge recombination and the limited visible-light absorption of semiconductor photocatalysts, many strategies have been developed in the past few decades and the most widely used one is to develop photocatalytic heterojunctions. This review attempts to summarize the recent progress in the rational design and fabrication of heterojunction photocatalysts, such as the semiconductor–semiconductor heterojunction, the semiconductor–metal heterojunction, the semiconductor–carbon heterojunction and the multicomponent heterojunction. The photocatalytic properties of the four junction systems are also discussed in relation to the environmental and energy applications, such as degradation of pollutants, hydrogen generation and photocatalytic disinfection. This tutorial review ends with a summary and some perspectives on the challenges and new directions in this exciting and still emerging area of research.

3,013 citations

Journal ArticleDOI
TL;DR: In this article, a family of isoreticular MOFs, based on the UiO-66 structure, was obtained from the three different linker ligands H2N−H2BDC, O2N −H2BDDC, and Br−H 2BDC and the physicochemical and chemical investigation of these materials demonstrate that this class of MOFs retains high thermal and chemical stabilities, even with functional groups present at the linker units.
Abstract: The development in the field MOF materials is moving from the discovery of new structures toward applications of the most promising materials. In most cases, specialized applications require incorporation of functional chemical groups. This work is a systematic investigation of the effect that simple substituents attached to the aromatic linker have on the stability and property to the parent MOF. A family of isoreticular MOFs, based on the UiO-66 structure was obtained from the three different linker ligands H2N−H2BDC, O2N−H2BDC, and Br−H2BDC. The physicochemical and chemical investigation of these materials demonstrate that this class of MOFs retains high thermal and chemical stabilities, even with functional groups present at the linker units. The results demonstrate the possibility of incorporating active functional groups into the UiO-66 structure almost without losing its exceptionally high thermal and chemical stability. It has been established that the functional groups, at least in the amino func...

1,430 citations

Journal ArticleDOI
TL;DR: Insight is provided into heterostructure photocatalysis and a novel way to design and fabricate high-performance semiconductor composites is described, which can greatly enhance the visible-light photocatalytic performance.
Abstract: The fabrication of multiple heterojunctions with tunable photocatalytic reactivity in full-range BiOBr–BiOI composites based on microstructure modulation and band structures is demonstrated. The multiple heterojunctions are constructed by precipitation at room temperature and characterized systematically. Photocatalytic experiments indicate that there are two types of heterostructures with distinct photocatalytic mechanisms, both of which can greatly enhance the visible-light photocatalytic performance for the decomposition of organic pollutants and generation of photocurrent. The large separation and inhibited recombination of electron–hole pairs rendered by the heterostructures are confirmed by electrochemical impedance spectra (EIS) and photoluminescence (PL). Reactive species trapping, nitroblue tetrazolium (NBT, detection agent of •O2–) transformation, and terephthalic acid photoluminescence (TA-PL) experiments verify the charge-transfer mechanism derived from the two types of heterostructures, as we...

651 citations

Journal ArticleDOI
01 Jul 2015-Small
TL;DR: In this review, the latest progress in MOF-involved solar-to-chemical energy conversion reactions are summarized according to their different roles in the photoredox chemical systems, e.g., photocatalysts, co-catalyststs, and hosts.
Abstract: Metal–organic frameworks (MOFs) have attracted significant research attention in diverse areas due to their unique physical and chemical characteristics that allow their innovative application in various research fields. Recently, the application of MOFs in heterogeneous photocatalysis for water splitting, CO2 reduction, and organic transformation have emerged, aiming at providing alternative solutions to address the world-wide energy and environmental problems by taking advantage of the unique porous structure together with ample physicochemical properties of the metal centers and organic ligands in MOFs. In this review, the latest progress in MOF-involved solar-to-chemical energy conversion reactions are summarized according to their different roles in the photoredox chemical systems, e.g., photocatalysts, co-catalysts, and hosts. The achieved progress and existing problems are evaluated and proposed, and the opportunities and challenges of MOFs and their related materials for their advanced development in photocatalysis are discussed and anticipated.

511 citations