Nanomaterials

Research

Jump to: Review

15 pages, 5271 KiB

Open AccessArticle

Construction of BPQDs/Ti₃C₂@TiO₂ Composites with Favorable Charge Transfer Channels for Enhanced Photocatalytic Activity under Visible Light Irradiation

by Ziyu Yao, Huajun Sun, Huiting Sui and Xiaofang Liu

Nanomaterials 2020, 10(3), 452; https://doi.org/10.3390/nano10030452 - 03 Mar 2020

Cited by 42 | Viewed by 4178

Abstract

Design and construction of double heterojunction is favorable to improve the separation and migration efficiency of photogenerated carriers, thus preferably solve the problems of environmental pollution and energy crisis. Herein, TiO₂ nanoparticles (NPs) are in-situ grown on highly conductive Ti₃C [...] Read more.

Design and construction of double heterojunction is favorable to improve the separation and migration efficiency of photogenerated carriers, thus preferably solve the problems of environmental pollution and energy crisis. Herein, TiO₂ nanoparticles (NPs) are in-situ grown on highly conductive Ti₃C₂ nanosheets via low-temperature hydrothermal strategy, and then black phosphorus quantum dots (BPQDs) are introduced on the surface of TiO₂ NPs. Under hydrothermal temperature 120 °C, the BPQDs/Ti₃C₂@TiO₂ photocatalyst exhibits remarkable enhanced photocatalytic degradation of methyl orange (MO) and hydrogen evolution reaction (HER) compared with BPQDs/Ti₃C₂ and Ti₃C₂@TiO₂ composites. Enhanced photocatalytic activity can be attributed to (i) the BPQDs with tunable bandgaps are deposited on the TiO₂ NPs to form intimate heterojunction, which facilitates the electrons transfer from the conduction band (CB) of BPQDs to the CB of TiO₂; (ii) the electrons quickly migrate from CB of TiO₂ NPs to the Ti₃C₂ nanosheets with excellent electronic conductivity via electron transfer channel, which is beneficial to prolong the lifetime of electrons and hinder the recombination of photogenerated carriers; (iii) the enhanced visible light absorption and enlarged specific surface area of BPQDs/Ti₃C₂@TiO₂ further accelerate the photocatalytic reaction. This work emphasizes the essential role of quantum dots in the construction of double heterojunction and the potential application of Ti₃C₂ MXene for improving photocatalytic activity. Full article

(This article belongs to the Special Issue Photocatalytic Nanomaterials)

► Show Figures

Graphical abstract

14 pages, 3714 KiB

Open AccessArticle

Facile One-Step Hydrothermal Fabrication of (Sr_0.6Bi_0.305)₂Bi₂O₇/SnO₂ Heterojunction with Excellent Photocatalytic Activity

by Di Zhu, Xinling Wang, Huiting An, Yan Zhong, Dianhui Wang, Chengying Tang and Chaohao Hu

Nanomaterials 2020, 10(2), 321; https://doi.org/10.3390/nano10020321 - 13 Feb 2020

Cited by 8 | Viewed by 2218

Abstract

The pyrochlore-type (Sr_0.6Bi_0.305)₂Bi₂O₇ (SBO), containing Bi³⁺ and Bi⁵⁺ mixed valent states, was recently found to be used as a new visible light responsive photocatalyst. Novel SBO/SnO₂ heterostructured composites were synthesized through [...] Read more.

The pyrochlore-type (Sr_0.6Bi_0.305)₂Bi₂O₇ (SBO), containing Bi³⁺ and Bi⁵⁺ mixed valent states, was recently found to be used as a new visible light responsive photocatalyst. Novel SBO/SnO₂ heterostructured composites were synthesized through a facile one-step hydrothermal method. The phase structure, morphology, chemical composition, and optical properties of the obtained samples were characterized by XRD, SEM, TEM, XPS, and UV-vis DRS. Compared to pure SBO and SnO₂, the synthesized SBO/SnO₂ composites exhibited significantly enhanced photocatalytic efficiency. The results indicated that the photoinduced holes and superoxide radicals play a dominant role and are the main reactive species during the degradation of Methylene Blue (MB) solution under visible light irradiation. Heterojunctions, formed in samples, directly contribute to the improvement of photocatalytic efficiency of SBO/SnO₂ composites, since it not only broadens the light response range, but also accelerates the separation of photogenerated carriers. Full article

(This article belongs to the Special Issue Photocatalytic Nanomaterials)

► Show Figures

Graphical abstract

15 pages, 3577 KiB

Open AccessArticle

Enhanced Visible-Light Photocatalytic Activity of Ag QDs Anchored on CeO₂ Nanosheets with a Carbon Coating

by Xiaogang Zheng, Qian Chen, Sihao Lv, Xiaojin Fu, Jing Wen and Xinhui Liu

Nanomaterials 2019, 9(11), 1643; https://doi.org/10.3390/nano9111643 - 19 Nov 2019

Cited by 24 | Viewed by 3252

Abstract

Ag quantum dots (QDs) anchored on CeO₂ nanosheets with a carbon coating (Ag/CeO₂@C) (composites) were prepared via an in situ reduction approach for the photocatalytic degradation of Cr(VI) and tetracycline hydrochloride (TCH) in the visible-light region. The photocatalytic activity of [...] Read more.

Ag quantum dots (QDs) anchored on CeO₂ nanosheets with a carbon coating (Ag/CeO₂@C) (composites) were prepared via an in situ reduction approach for the photocatalytic degradation of Cr(VI) and tetracycline hydrochloride (TCH) in the visible-light region. The photocatalytic activity of Ag/CeO₂@C was greatly affected by carbon content, Ag-doping content, Cr(VI) concentration, pH value, and inorganic ions. Enhanced photocatalytic activity was obtained by Ag/CeO₂@C (compared to CeO₂ and CeO₂@C), of which 3-Ag/CeO₂@C-2 with an Ag-doping content of 5.41% presented the best removal efficiency and the most superior stability after five cycles. ·O₂⁻ and ·OH radicals were crucial for the photocatalytic capacity of 3-Ag/CeO₂@C-2. The combined effect of the surface plasma resonance (SPR) of Ag QDs, an electron trapper of carbon shells, and the redox activity of the Ce(III)/Ce(IV) coupling induced efficient charge transfer and separation, suppressing the recombination of electron–hole pairs. Full article

(This article belongs to the Special Issue Photocatalytic Nanomaterials)

► Show Figures

Graphical abstract

16 pages, 6833 KiB

Open AccessArticle

Continuously Improved Photocatalytic Performance of Zn₂SnO₄/SnO₂/Cu₂O Composites by Structural Modulation and Band Alignment Modification

by Tiekun Jia, Junchao An, Dongsheng Yu, Jili Li, Fang Fu, Kun Wang and Weimin Wang

Nanomaterials 2019, 9(10), 1390; https://doi.org/10.3390/nano9101390 - 28 Sep 2019

Cited by 13 | Viewed by 2517

Abstract

Improving the photocatalytic performance of multi-component photocatalysts through structural modulation and band alignment engineering has attracted great interest in the context of solar energy utilization and conversion. In our work, Zn₂SnO₄/SnO₂ hierarchical architectures comprising nanorod building block assemblies [...] Read more.

Improving the photocatalytic performance of multi-component photocatalysts through structural modulation and band alignment engineering has attracted great interest in the context of solar energy utilization and conversion. In our work, Zn₂SnO₄/SnO₂ hierarchical architectures comprising nanorod building block assemblies were first achieved via a facile solvothermal synthesis route with lysine and ethylenediamine (EDA) as directing agents, and then chemically etched in NaOH solution to enlarge the surface area and augment active sites. The etched Zn₂SnO₄/SnO₂ hierarchical architectures were further decorated by Cu₂O nanoparticles though an in situ chemical deposition method based on band alignment engineering. In comparison with unetched Zn₂SnO₄/SnO₂, the specific surface area of Zn₂SnO₄/SnO₂/Cu₂O hierarchical architectures became larger, and the responsive region and absorbance intensity became wider and higher in the whole visible-light range. Zn₂SnO₄/SnO₂/Cu₂O hybrid photocatalysts presented enormously improved visible-light photocatalytic behaviour for Rhodamine B (RhB) decomposition. The enhancement of photocatalytic behaviour was dominantly attributed to the synergy effect of the larger specific surface area, higher light absorption capacity, and more effective photo-induced charge carrier separation and migration. A proposed mechanism for the enormously promoted photocatalytic behaviour is brought forth on the basis of the energy-band structure combined with experimental results. Full article

(This article belongs to the Special Issue Photocatalytic Nanomaterials)

► Show Figures

Figure 1

17 pages, 6050 KiB

Open AccessArticle

Preparation of TiO₂ and Fe-TiO₂ with an Impinging Stream-Rotating Packed Bed by the Precipitation Method for the Photodegradation of Gaseous Toluene

by Guangping Zeng, Qiaoling Zhang, Youzhi Liu, Shaochuang Zhang and Jing Guo

Nanomaterials 2019, 9(8), 1173; https://doi.org/10.3390/nano9081173 - 16 Aug 2019

Cited by 21 | Viewed by 3764

Abstract

Nano-TiO₂ has always been one of the most important topics in the research of photocatalysts due to its special activity and stability. However, it has always been difficult to obtain nano-TiO₂ with high dispersion, a small particle size and high photocatalytic [...] Read more.

Nano-TiO₂ has always been one of the most important topics in the research of photocatalysts due to its special activity and stability. However, it has always been difficult to obtain nano-TiO₂ with high dispersion, a small particle size and high photocatalytic activity. In this paper, nano-TiO₂ powder was prepared by combining the high-gravity technique and direct precipitation method in an impinging stream-rotating packed bed (IS-RPB) reactor followed by Fe³⁺ in-situ doping. TiOSO₄ and NH₃·H₂O solutions were cut into very small liquid microelements by high-speed rotating packing, and the mass transfer and microscopic mixing of the nucleation and growth processes of nano-TiO₂ were strengthened in IS-RPB, which was beneficial to the continuous production of high quality nano-TiO₂. Pure TiO₂ and iron-doped nano-TiO₂ (Fe-TiO₂) were obtained in IS-RPB and were investigated by means of X-ray diffraction (XRD), Raman, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS) and Brunauer–Emmett–Teller (BET) analysis, which found that pure TiO₂ had a particle size of about 12.5 nm, good dispersibility and a complete anatase crystal at the rotating speed of packing of 800 rpm and calcination temperature of 500 °C. The addition of Fe³⁺ did not change the crystalline structure of TiO₂. Iron was highly dispersed in TiO₂ without the detection of aggregates and was found to exist in a positive trivalent form by XPS. With the increase of iron doping, the photoresponse range of TiO₂ to visible light was broadened from 3.06 eV to 2.26 eV. The degradation efficiency of gaseous toluene by Fe-TiO₂ under ultraviolet light was higher than that of pure TiO₂ and commercial P25 due to Fe³⁺ effectively suppressing the recombination of TiO₂ electrons and holes; the highest efficiency produced by 1.0% Fe-TiO₂ was 95.7%. Full article

(This article belongs to the Special Issue Photocatalytic Nanomaterials)

► Show Figures

Figure 1

13 pages, 3383 KiB

Open AccessArticle

Enhancement in Photoelectrochemical Performance of Optimized Amorphous SnS₂ Thin Film Fabricated through Atomic Layer Deposition

by Weiguang Hu, Truong Thi Hien, Dojin Kim and Hyo Sik Chang

Nanomaterials 2019, 9(8), 1083; https://doi.org/10.3390/nano9081083 - 28 Jul 2019

Cited by 17 | Viewed by 3583

Abstract

Two-dimensional (2D) nanomaterials have distinct optical and electrical properties owing to their unique structures. In this study, smooth 2D amorphous tin disulfide (SnS₂) films were fabricated by atomic layer deposition (ALD), and applied for the first time to photoelectrochemical water splitting. [...] Read more.

Two-dimensional (2D) nanomaterials have distinct optical and electrical properties owing to their unique structures. In this study, smooth 2D amorphous tin disulfide (SnS₂) films were fabricated by atomic layer deposition (ALD), and applied for the first time to photoelectrochemical water splitting. The optimal stable photocurrent density of the 50-nm-thick amorphous SnS₂ film fabricated at 140 °C was 51.5 µA/cm² at an oxygen evolution reaction (0.8 V vs. saturated calomel electrode (SCE)). This value is better than those of most polycrystalline SnS₂ films reported in recent years. These results are attributed mainly to adjustable optical band gap in the range of 2.80 to 2.52 eV, precise control of the film thickness at the nanoscale, and the close contact between the prepared SnS₂ film and substrate. Subsequently, the photoelectron separation mechanisms of the amorphous, monocrystalline, and polycrystalline SnS₂ films are discussed. Considering above advantages, the ALD amorphous SnS₂ film can be designed and fabricated according to the application requirements. Full article

(This article belongs to the Special Issue Photocatalytic Nanomaterials)

► Show Figures

Graphical abstract

15 pages, 4425 KiB

Open AccessArticle

Ag₃PO₄ Deposited on CuBi₂O₄ to Construct Z-Scheme Photocatalyst with Excellent Visible-Light Catalytic Performance Toward the Degradation of Diclofenac Sodium

by Xiaojuan Chen, Chunmu Yu, Runliang Zhu, Ning Li, Jieming Chen, Shuai Li, Wei Xia, Song Xu, Hailong Wang and Xin Chen

Nanomaterials 2019, 9(7), 959; https://doi.org/10.3390/nano9070959 - 30 Jun 2019

Cited by 21 | Viewed by 3941

Abstract

CuBi₂O₄/Ag₃PO₄ was synthesized through a combination of hydrothermal synthesis and an in situ deposition method with sodium stearate as additives, and their textures were characterized with XRD, XPS, SEM/HRTEM, EDS, UV-Vis, and PL. Then, the photodegradation [...] Read more.

CuBi₂O₄/Ag₃PO₄ was synthesized through a combination of hydrothermal synthesis and an in situ deposition method with sodium stearate as additives, and their textures were characterized with XRD, XPS, SEM/HRTEM, EDS, UV-Vis, and PL. Then, the photodegradation performance of CuBi₂O₄/Ag₃PO₄ toward the degradation of diclofenac sodium (DS) was investigated, and the results indicate that the degradation rate of DS in a CuBi₂O₄/Ag₃PO₄ (1:1) system is 0.0143 min⁻¹, which is 3.6 times that in the blank irradiation system. Finally, the photocatalytic mechanism of CuBi₂O₄/Ag₃PO₄ was discussed, which follows the Z-Scheme theory, and the performance enhancement of CuBi₂O₄/Ag₃PO₄ was attributed to the improved separation efficiency of photogenerated electron–hole pairs. Full article

(This article belongs to the Special Issue Photocatalytic Nanomaterials)

► Show Figures

Figure 1

13 pages, 4865 KiB

Open AccessArticle

Visible-Light-Driven Photocatalytic Activity of Magnetic BiOBr/SrFe₁₂O₁₉ Nanosheets

by Taiping Xie, Jiao Hu, Jun Yang, Chenglun Liu, Longjun Xu, Jiankang Wang, Yuan Peng, Songli Liu, Xiuyu Yin and Yuanzhen Lu

Nanomaterials 2019, 9(5), 735; https://doi.org/10.3390/nano9050735 - 13 May 2019

Cited by 15 | Viewed by 3414

Abstract

Magnetic BiOBr/SrFe₁₂O₁₉ nanosheets were successfully synthesized using the hydrothermal method. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and UV-visible diffused reflectance spectra (UV-DRS), and the magnetic properties were tested using [...] Read more.

Magnetic BiOBr/SrFe₁₂O₁₉ nanosheets were successfully synthesized using the hydrothermal method. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and UV-visible diffused reflectance spectra (UV-DRS), and the magnetic properties were tested using a vibration sample magnetometer (VSM). The as-produced composite with an irregular flaky-shaped aggregate possesses a good anti-demagnetization ability (Hc = 861.04 G) and a high photocatalytic efficiency. Under visible light (λ > 420 nm) and UV light-emitting diode (LED) irradiation, the photodegradation rates of Rhodamine B (RhB) using BiOBr/SrFe₁₂O₁₉ (5 wt %) (BOB/SFO-5) after 30 min of reaction were 97% and 98%, respectively, which were higher than that using BiOBr (87%). The degradation rate of RhB using the recovered BiOBr/5 wt % SrFe₁₂O₁₉ (marked as BOB/SFO-5) was still more than 85% in the fifth cycle, indicating the high stability of the composite catalyst. Meanwhile, after five cycles, the magnetic properties were still as stable as before. The radical-capture experiments proved that superoxide radicals and holes were main active species in the photocatalytic degradation of RhB. Full article

(This article belongs to the Special Issue Photocatalytic Nanomaterials)

► Show Figures

Graphical abstract

11 pages, 5629 KiB

Open AccessArticle

One-Pot Synthesis of BiCuSO Nanosheets under Ambient Atmosphere as Broadband Spectrum Photocatalyst

by Huanchun Wang, Junping Ding, Haomin Xu, Lina Qiao, Xuanjun Wang and Yuanhua Lin

Nanomaterials 2019, 9(4), 540; https://doi.org/10.3390/nano9040540 - 03 Apr 2019

Cited by 5 | Viewed by 3013

Abstract

Cuprous based chalcogenides have attracted intensive research interest due to the potential applications in solar energy conversion. However, typical fabrications of these compounds are often carried out under severe conditions, such as inert gas protection, high vacuum, and/or extreme high temperature. Here we [...] Read more.

Cuprous based chalcogenides have attracted intensive research interest due to the potential applications in solar energy conversion. However, typical fabrications of these compounds are often carried out under severe conditions, such as inert gas protection, high vacuum, and/or extreme high temperature. Here we reported a one-pot process for cuprous based chalcogenides synthesis in aqueous solution. A strategy for BiCuSO nanosheets fabrication without toxic chemicals or rigorous reagents at pretty low temperatures under an ambient atmosphere was established, with the practicality of morphology controlling and the compatibility of multifarious precursors. Platelike BiCuSO with a thickness range from several to hundreds nanometers are fabricated by adjusting the alkali concentration, reaction time, and temperature. The positive effect of alkali hydroxide concentration is proposed cautiously based on the experimental results. The photocatalytic activities of BiCuSO nanosheet under UV, visible, and near-infrared irradiation were also investigated. BiCuSO obtained at room temperature with a thickness of 4.5 nm showed the most impressive efficiency to decompose organic contaminants. Our research presented a new way for cuprous sulfides fabrication, and might open up a new vista for large-scale synthesis of cuprous based materials as promising broadband spectrum light-absorbing materials. Full article

(This article belongs to the Special Issue Photocatalytic Nanomaterials)

► Show Figures

Graphical abstract

19 pages, 3354 KiB

Open AccessArticle

Challenges in Determining the Location of Dopants, to Study the Influence of Metal Doping on the Photocatalytic Activities of ZnO Nanopowders

by Takuya Tsuzuki, Rongliang He, Aaron Dodd and Martin Saunders

Nanomaterials 2019, 9(3), 481; https://doi.org/10.3390/nano9030481 - 25 Mar 2019

Cited by 26 | Viewed by 4004

Abstract

Impurity doping is one of the common approaches to enhance the photoactivity of semiconductor nanomaterials by increasing photon-capture efficiency in the visible light range. However, many studies on the doping effects have produced inconclusive and conflicting results. There are some misleading assumptions and [...] Read more.

Impurity doping is one of the common approaches to enhance the photoactivity of semiconductor nanomaterials by increasing photon-capture efficiency in the visible light range. However, many studies on the doping effects have produced inconclusive and conflicting results. There are some misleading assumptions and errors that are frequently made in the data interpretation, which can lead to inconsistent results about the doping effects on photocatalysis. One of them is the determination of the location of dopants. Even using advanced analytical techniques, it is still challenging to distinguish between bulk modification and surface modification. The paper provides a case study of transition-metal-doped ZnO nanoparticles, whereby demonstrating common pitfalls in the interpretation of the results of widely-used analytical methods in detail, and discussing the importance of using a combination of many characterization techniques to correctly determine the location of added impurities, for elucidating the influence of metal doping on the photocatalytic activities of semiconductor nanoparticles. Full article

(This article belongs to the Special Issue Photocatalytic Nanomaterials)

► Show Figures

Graphical abstract

22 pages, 4983 KiB

Open AccessArticle

One-Step Low Temperature Hydrothermal Synthesis of Flexible TiO₂/PVDF@MoS₂ Core-Shell Heterostructured Fibers for Visible-Light-Driven Photocatalysis and Self-Cleaning

by Zhi-Guang Zhang, Hui Liu, Xiao-Xiong Wang, Jun Zhang, Miao Yu, Seeram Ramakrishna and Yun-Ze Long

Nanomaterials 2019, 9(3), 431; https://doi.org/10.3390/nano9030431 - 14 Mar 2019

Cited by 45 | Viewed by 5554

Abstract

Novel flexible and recyclable core-shell heterostructured fibers based on cauliflower-like MoS₂ and TiO₂/PVDF fibers have been designed through one-step hydrothermal treatment based on electrospun tetrabutyl orthotitanate (TBOT)/PVDF fibers. The low hydrothermal temperature avoids the high temperature process and keeps the [...] Read more.

Novel flexible and recyclable core-shell heterostructured fibers based on cauliflower-like MoS₂ and TiO₂/PVDF fibers have been designed through one-step hydrothermal treatment based on electrospun tetrabutyl orthotitanate (TBOT)/PVDF fibers. The low hydrothermal temperature avoids the high temperature process and keeps the flexibility of the as-synthesized materials. The formation mechanism of the resultant product is discussed in detail. The composite of MoS₂ not only expands the light harvesting window to include visible light, but also increases the separation efficiency of photo-generated electrons and holes. The as-prepared product has proven to possess excellent and stable photocatalytic activity in the degradation of Rhodamine B and levofloxacin hydrochloride under visible light irradiation. In addition, the TiO₂/PVDF@MoS₂ core-shell heterostructured fibers exhibit self-cleaning property to dye droplets under visible light irradiation. Meanwhile, due to its hydrophobicity, the resultant product can automatically remove dust on its surface under the rolling condition of droplets. Hence, the as-prepared product cannot only degrade the contaminated compounds on the surface of the material, but also reduce the maintenance cost of the material due to its self-cleaning performance. Therefore, the as-prepared product possesses potential applications in degradation of organic pollutants and water treatment, which makes it a prospective material in the field of environmental treatment. Full article

(This article belongs to the Special Issue Photocatalytic Nanomaterials)

► Show Figures

Figure 1

14 pages, 5725 KiB

Open AccessArticle

Three-Dimensional Structure of PANI/CdS NRs-SiO₂ Hydrogel for Photocatalytic Hydrogen Evolution with High Activity and Stability

by Jinrong Lu, Xin Zhang, Huiyuan Gao and Wenquan Cui

Nanomaterials 2019, 9(3), 427; https://doi.org/10.3390/nano9030427 - 13 Mar 2019

Cited by 15 | Viewed by 3480

Abstract

Three-dimensional PANI/CdSNRs-SiO₂ hydrogel (CdS NRs-PANI-SiO₂) was synthesized by loading polyaniline (PANI) onto the semiconductor CdS nanorods (NRs) surface and loading the binary complex on SiO₂ gel. The structure, optical properties, and electrochemical properties of the composite were studied in [...] Read more.

Three-dimensional PANI/CdSNRs-SiO₂ hydrogel (CdS NRs-PANI-SiO₂) was synthesized by loading polyaniline (PANI) onto the semiconductor CdS nanorods (NRs) surface and loading the binary complex on SiO₂ gel. The structure, optical properties, and electrochemical properties of the composite were studied in detail. The hydrogen production amount of CdS NRs-PANI (3%)-SiO₂ (20%) increased in comparison with CdS NRs and reached 43.25 mmol/g in 3 h under visible light. The three-dimensional structure of SiO₂ hydrogel increased the specific surface area of the catalyst, which was conducive to exposing more active sites of the catalyst. In addition, the conductive polymer PANI coated on CdS NRs played the role of conductive charge and effectively inhibited the photo-corrosion of CdS NRs. In addition, the recovery experiment showed that the recovery rate of the composite catalyst reached 90% and hydrogen production efficiency remained unchanged after five cycles, indicating that the composite catalyst had excellent stability. Full article

(This article belongs to the Special Issue Photocatalytic Nanomaterials)

► Show Figures

Figure 1

18 pages, 28464 KiB

Open AccessArticle

Photocatalytic and Photo-Fenton Catalytic Degradation Activities of Z-Scheme Ag₂S/BiFeO₃ Heterojunction Composites under Visible-Light Irradiation

by Lijing Di, Hua Yang, Tao Xian, Xueqin Liu and Xiujuan Chen

Nanomaterials 2019, 9(3), 399; https://doi.org/10.3390/nano9030399 - 09 Mar 2019

Cited by 107 | Viewed by 6408

Abstract

Z-scheme Ag₂S/BiFeO₃ heterojunction composites were successfully prepared through a precipitation method. The morphology and microstructure characterization demonstrate that Ag₂S nanoparticles (30–50 nm) are well-decorated on the surfaces of polyhedral BiFeO₃ particles (500–800 nm) to form Ag₂ [...] Read more.

Z-scheme Ag₂S/BiFeO₃ heterojunction composites were successfully prepared through a precipitation method. The morphology and microstructure characterization demonstrate that Ag₂S nanoparticles (30–50 nm) are well-decorated on the surfaces of polyhedral BiFeO₃ particles (500–800 nm) to form Ag₂S/BiFeO₃ heterojunctions. The photocatalytic and photo-Fenton catalytic activities of the as-derived Ag₂S/BiFeO₃ heterojunction composites were evaluated by the degradation of methyl orange (MO) under visible-light irradiation. The photocatalytic result indicates that the Ag₂S/BiFeO₃ composites exhibit much improved photocatalytic activities when compared with bare Ag₂S and BiFeO₃. The optimum composite sample was observed to be 15% Ag₂S/BiFeO₃ with an Ag₂S mass fraction of 15%. Furthermore, the addition of H₂O₂ can further enhance the dye degradation efficiency, which is due to the synergistic effects of photo- and Fenton catalysis. The results of photoelectrochemical and photoluminescence measurements suggest a greater separation of the photoexcited electron/hole pairs in the Ag₂S/BiFeO₃ composites. According to the active species trapping experiments, the photocatalytic and photo-Fenton catalytic mechanisms of the Ag₂S/BiFeO₃ composites were proposed and discussed. Full article

(This article belongs to the Special Issue Photocatalytic Nanomaterials)

► Show Figures

Graphical abstract

Review

Jump to: Research

33 pages, 6298 KiB

Open AccessReview

TiO₂-based Photocatalytic Cementitious Composites: Materials, Properties, Influential Parameters, and Assessment Techniques

by Fatemeh Hamidi and Farhad Aslani

Nanomaterials 2019, 9(10), 1444; https://doi.org/10.3390/nano9101444 - 11 Oct 2019

Cited by 89 | Viewed by 8158

Abstract

Applications of heterogeneous photocatalytic processes based on semiconductor particles in cement-based materials have received great attention in recent years to enhance the aesthetic durability of buildings and reducing global environmental pollution. Amongst all, titanium dioxide (TiO₂) is the most widely used [...] Read more.

Applications of heterogeneous photocatalytic processes based on semiconductor particles in cement-based materials have received great attention in recent years to enhance the aesthetic durability of buildings and reducing global environmental pollution. Amongst all, titanium dioxide (TiO₂) is the most widely used semiconductor particle in structural materials with photocatalytic activity because of its low cost, chemically stable nature, and absence of toxicity. Utilization of TiO₂ in combination with cement-based materials would plunge the concentration of urban pollutants such as NO_x. In fact, cementitious composites containing TiO₂ have already found applications in self-cleaning buildings, antimicrobial surfaces, and air-purifying structures. This paper aims to present a comprehensive review on TiO₂-based photocatalysis cement technology, its practical applications, and research gaps for further progression of cementitious materials with photocatalytic activity. Full article

(This article belongs to the Special Issue Photocatalytic Nanomaterials)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Photocatalytic Nanomaterials

Share This Special Issue

Special Issue Editor

Special Issue Information

Keywords

Published Papers (14 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI