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1.
Constructing heterojunction provides a promising tactic to improve the photocatalytic efficiency of catalysts. In this paper, hierarchical FeIn 2S 4/BiOBr heterostructure photocatalysts were prepared by facile two step methods and applied to effectively remove ciprofloxacin (CIP) and tetracycline (TC) under visible light. Compared to single catalyst, FeIn 2S 4/BiOBr hybrids display significantly improved photocatalytic activity. Among the series, 6 wt% FeIn 2S 4/BiOBr shows the optimal photocatalytic performance, where the degradation efficiencies of TC and CIP are 3.15 and 2.88 times greater than pure BiOBr, respectively. Such an improvement could arise from the S-scheme heterojunctions and unique hierarchical structures, which brings stronger light absorption, higher photoexcited charge separation efficiency and superior redox ability. Furthermore, 6 wt% FeIn 2S 4/BiOBr composite exhibits excellent stability and reusability. Radical capture experiments and EPR analyses uncover that O 2–, h + and OH are primarily reactive substances during photocatalytic removal of TC. The products of TC were detected by LC-MS analyses and possible decomposition paths are proposed. Eventually, a possible photodegradation mechanism over FeIn 2S 4/BiOBr S-scheme heterojunction is proposed. These findings supply new perspective for the simple synthesis of S-scheme photocatalysts with promising applications in environment remediation. 相似文献
2.
The development of high-efficiency heterojunction with improved photocatalytic property is regarded as a promising way to decontaminate wastewater. In this study, Z-Scheme g-C3N4/H-TiO2 heterojunctions with different proportions were synthesized. The photocatalytic degradation of rhodamine B (RhB) was studied under visible light irradiation. Among them, 10% g-C3N4/H-TiO2 photocatalyst had the best performance, and the degradation rate of RhB was 65% within 120 min. In addition, 10% g-C3N4/H-TiO2 photocatalyst had high stability, and its photocatalytic activity did not decrease significantly after four cycles. Through photocurrent analysis, it is found that the photogenerated carriers have obviously excellent separation and transfer characteristics, which makes the 10% g-C3N4/H-TiO2 photocatalyst have good degradation performance. Electron paramagnetic resonance (ESR) experiments showed that ·OH and ·O2? were active radicals during degradation. 相似文献
3.
At present, the construction of high-efficiency photocatalytic degradation system of antibiotic pollutants has become a research hotspot. In this paper, Bi 28O 32(SO 4) 10/NiAl LDH photocatalyst with three-dimensional spherical morphology was successfully prepared by hydrothermal method followed by calcination, thus applying to the degradation of tetracycline. The characterization and photochemical analysis of the resulted material were used to determine the type of formed heterojunction. Bi 28O 32(SO 4) 10 and NiAl LDH build a close contact interface. The matching band gap structure makes S-scheme heterojunction formed between the two single component. Benefited from this structure, the Bi 28O 32(SO 4) 10/NiAl LDH composite with the mass ratio of 1:1 exhibited 95% efficiency in degradation of tetracycline after irradiation for 120 min, and it is stable, reusable and universal. The apparent rate constant of TC degradation by heterojunction catalyst is greatly increased, which is 5.35 and 4.91 times that of Bi 28O 32(SO 4) 10 and NiAl LDH. Overall, this paper provides a way of thinking for the design of new bismuth based photocatalytic materials, and thus providing a reference for the rational design of S-scheme heterojunction. 相似文献
4.
Graphitic carbon nitride (g-C3 N4) with the merits of high visible light absorption,proper electronic band structure with high conduction band edge and variable modulation,is viewed as a promising photocatalyst for practical use.To alleviate its high recombination rate of photo-excited charge carriers and maximize the photocatalytic performances,it is paramount to design highly effective transfer channels for photo-excited charge carriers.Ferroelectric materials can have the charge carriers transport in opposite directions owing to the internal spontaneous polarization,which may be suitable for constructing the heterostructure with g-C3N4 for efficient charge separation.Inspired by this concept,herein ferroelec tric PbTiO3,which can be the visible-light absorber,is coupled with g-C3N4 to construct PbTiO3/g-C3N4 heterostructure with close contact via Pb-N bond by the facile post thermal treatment.The optimized PbTiO3/g-C3N4 heterostructure exhibited excellent photocatalytic and photoelectrochemical activities under visible light irradiation.Moreover,the simultaneous application of ultrasound-induced mechanical waves can further improve its photocatalytic activities through reinforcing the built-in piezoelectric field.This work proposes a widely applicable strategy for the fabrication of high-performance ferroelectric based photocatalysts and also provides some new ideas for developing the understanding of ferroelectric photocatalysis. 相似文献
5.
The quest to develop efficient photocatalysts in order to maintain a harmonious ecosystem by reducing water pollution from wastewater discharged from various industries is still in progress. Herein, we report a photocatalyst synthesized from exfoliated graphitic carbon nitride (gC 3N 4(ex)) and cadmium sulfide (CdS) which manifested excellent catalytic activity towards the degradation of various textile dyes in the presence of H 2O 2 (50CdS-50gC 3N 4(ex)). Under optimum reaction conditions, ~100 % degradation of some textile dyes such as Turq CL 5B, Red CL 5B, Yell CL 2R, Navy CLR, CB Sol Navy R, and Lanasol Black CE were observed in 10, 15, 30, 25, 30, and 15 min, respectively, when 50CdS-50gC 3N 4(ex) was used as the photocatalyst. This excellent photocatalytic efficiency of 50CdS-50gC 3N 4(ex) ascends from the establishment of synergy between nanorod-shaped CdS and exfoliated tubular-shaped gC 3N 4 due to their intimate concomitance in the nanocomposite. Moreover, the catalyst showed ~93 % catalytic efficiency as well as no change in the crystal structure or morphology after five catalytic cycles. Hence, this work puts forward a highly efficient environment-friendly, and reusable catalyst (50CdS-50gC 3N 4(ex)) which demonstrated its excellent potentiality to be utilized in the treatment of polluted effluents from textile industries under solar or blue LED irradiation. 相似文献
8.
Journal of Materials Science: Materials in Electronics - The development of an efficient and photostable heterostructured photocatalyst has attracted a great deal of attention for the degradation... 相似文献
9.
Journal of Materials Science: Materials in Electronics - A g-C3N4 nanorod/Ag3PO4 (CN-A) Z-Scheme heterojunction, which can response to visible light, was prepared through a convenient and green... 相似文献
10.
This work was designed to synthesize SrMoO 4/g-C 3N 4 heterojunction for efficient degradation of tetracycline (TC) hydrochloride via photocatalysis. SrMoO 4/g-C 3N 4 samples were prepared through a grinding and roasting process. The prepared nanocomposite exhibited excellent visible-light-driven photocatalytic activity. The reaction rate of TC photodegradation reaches 0.0171 min ?1, which is 5.9 times higher than that of neat g-C 3N 4. The origin of the high photoactivity of SrMoO 4/g-C 3N 4 was investigated using a variety of characterization techniques including XRD, FT-IR, TG, SEM, TEM, XPS, DRS, Mott-Schottky, PL, PC, and EIS. Result showed that the added SrMoO 4 was closely loaded on the g-C 3N 4 surface, which is conducive to the electron transfer between SrMoO 4 and g-C 3N 4. Mott-Schottky analysis indicated that SrMoO 4 has a lower conduction band (CB) position than g-C 3N 4. As a result, photogenerated electrons in g-C 3N 4 can move to the CB of SrMoO 4 to hinder the recombination of charge carriers, thereby increasing the photocatalytic activity under visible light. The cycling test further suggested that the SrMoO 4/g-C 3N 4 heterojunction has good stability in the photocatalytic degradation of TC. Super oxygen radicals and holes are the main reactive species. 相似文献
11.
In this study, a novel oxygen vacancy-rich BiOCl/ZnMoO4 composites were successfully prepared by a simple two-step method. Experimental results indicated that the content of BiOCl with oxygen vacancies played an important role in photocatalytic performance of OBZM heterostructures. OBZM-5 exhibited a highly enhanced photocatalytic activity under visible light irradiation compared to pure BiOCl, Ov-BiOCl, ZnMoO4 and other OBZM composites, which can be attributed to the efficient separation and transfer of photogenerated charge carrier. The photocatalytic degradation efficiency of rhodamine B (RhB) can reach 99% within 40 min and almost all of norfloxacin (NOR) can be degradated after 100 min by OBZM-5. In addition, OBZM-5 displayed a good stability during the photocatalytic process, which favored a long-term use. Moreover, a possible photocatalytic mechanism was proposed based on the active species trapping experiments and electron spin resonance (ESR) tests, verifying that the photogenerated holes (h+) and ·O2? radicals were the dominating active species. 相似文献
13.
A visible-light-driven g-C 3N 4/g-C 3N 4 isotype heterojunction photocatalyst was synthesized by one-step thermal treatment using urea and thiourea as the precursor. The photocatalytic activity of as-prepared photocatalyst was evaluated through the degradation of rhodamine B (RhB) and tetracycline hydrochloride (TC) under the visible light irradiation. The hybrid showed enhanced photocatalytic activity in photodegradating the applied pollutants as compared with single g-C 3N 4. When the ratio of urea to thiourea was 2:1, the prepared isotype heterojunction exhibited the highest photocatalytic activity and the photodegradation rates for RhB and TC were 99.8% and 95.1% after being visible light irradiated for 1 h and 4 h respectively. The enhanced photocatalytic performance of the isotype heterojunction is ascribed to the enhanced charge separation efficiency. After being reused for 5 times, the hybrid still showed excellent recyclability and chemical stability. Furthermore, NaI, BQ and IPA were used as the sacrificial agents for studying the surface reactions in the photocatalytic process. The method used in this work provides a new pathway to achieve more efficient degradation of antibiotics and to stimulate further studies in this important field. 相似文献
14.
One-dimensional (1D) hierarchically structured CdS nanoparticles (NPs)/NiO nanofibers (NFs) heterostructures with remarkable removal efficiency for diazo dye Congo red (CR) were fabricated by a stepwise synthesis process, which was involved a chemical bathing deposition combined with calcination, and a microwave-assisted wet chemical reaction. The crystal phases, morphologies, optical absorption properties, and adsorption/photocatalytic activity of as-prepared products were investigated by XRD, FESEM, TEM, high-resolution TEM (HRTEM), N 2 adsorption/desorption isotherms, UV–Vis diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) spectrum respectively. The experimental results indicated that binary satellite- core CdS NPs/NiO NFs heterojunctions are comprised of n-type CdS NPs with size of 10–30 nm decorated onto 1D p-type NiO NFs with diameter of 60–180 nm and length up to microns, which are self-assembled by nanoparticles with 30–100 nm in size. The possible formation mechanism for satellite-core structured CdS/NiO heterojunction is proposed. Interestingly, the decolorization efficiency over CdS/NiO heterostructures reached up to 91.2% in removal of aqueous CR at high concentration within 40 min under visible light irradiation, which was approximately 5.2 and 3.8 times as high as that of pure CdS nanocrystals (NCs) and the mixture of NiO NFs and CdS NCs. Furthermore, the possible photocatalytic mechanism was also investigated. The as-designed hybrid CdS NPs/NiO NFs heterostructures exhibited improved photocatalytic activity, which is attributed to the enhancement of the visible light adsorption, the efficient separation of photogenerated electrons and holes, and the high adsorption capacity towards CR molecules, thereby displaying superior visible- light-driven photodegradation of CR in high concentration. This work may provide a green engineering heterojunction technology to develop the advanced multifunctional nanocomposites for their applications in wastewater purification. 相似文献
15.
Journal of Materials Science: Materials in Electronics - A novel BiOCl/CoAl-LDH direct Z-scheme photocatalyst was successfully designed and fabricated via pH adjustment and solvent thermal method.... 相似文献
17.
Rational design of organic-inorganic heterojunction photocatalyst has become a research hotspot of recent researchers due to their abundance and cost effectivity. Herein, we present the integrated photocatalyst carbon dot (CD) decorated on g-C 3N 4/AgCl heterojunction synthesized by simple impregnation method. The primary confirmation for the as-prepared samples has been carried out by various characterization techniques. From the obtained results, the ternary nanocomposite demonstrated a prominent photocatalytic activity which was almost 10 and 51 fold higher than pure g-C 3N 4 in the degradation of organic dyes. The reasons behind the improved efficiency are (i) The introduced CD facilitates broader absorption in the visible region because of π-conjugated CDs and provide favorable electron kinetics by creating trap states at the CD/g-C 3N 4 interface. (ii) The AgCl acts as an electron sinker and reduce the carrier’s recombination. To justify the photocatalytic activity, a possible mechanism was proposed and verified by trapping experiments. Finally, this approach could be a new one in an organic-inorganic hybrid photocatalyst for the degradation of organic dyes. 相似文献
18.
The challenges like the photocatalytic reduction of N 2 and elimination of contaminants from the wastewater are accessible by low cost, stable, and visible-light-driven semiconductor-based photocatalysis. A novel g-C 3N 4/BiSI nanocomposite was synthesized by hydrothermal method and applied for the first time in photocatalytic nitrogen fixation and degradation of methylene blue dye and phenol. The physicochemical features of the photocatalysts were studied by XRD, XPS, FTIR, BET, DRS, FESEM, TEM, EDX mapping, PL, EIS, Mott-Schottky, and photocurrent techniques. Experimental results showed that the production of ammonia in the presence of g-C 3N 4/BiSI nanocomposite was 1280 μmol L ?1 g ?1, while this values for g-C 3N 4 and BiSI were 274 μmol g ?1 L ?1 and 126 μmol g ?1 L ?1, respectively. Moreover prepared nanocomposite exhibited a higher rate constant in the MB (537.5 × 10 ?4 min ?1) and phenol (353 × 10 ?4 min ?1) degradation compared with the counterparts. The charge separation efficiency obviously improved, which was ascribed to the charges migration between g-C 3N 4 and BiSI in an n-n heterojunction system. In addition, high specific surface area and strong visible light absorption were identified as other factors affecting photocatalytic performance. This unique heterojunction photocatalyst has wide application prospects in environmental treatment. 相似文献
19.
Hexagonal zinc indium sulfide coupled g-C 3N 4 (H-ZnIn 2S 4/g-C 3N 4) nanocomposites were synthesized using chemisorption method and its performance towards photoelectrochemical water splitting activity was studied. The H-ZnIn 2S 4/g-C 3N 4 (H-ZIS/CN) nanocomposites exhibited ∼ 1.9 times enhanced photoelectrochemical performance as compared to the H-ZnIn 2S 4. The enhancement in the PEC water splitting activity of H-ZIS/CN nanocomposite is ascribed to the formation of type-II heterojunction which resulted in improved separation of photogenerated charge carriers and faster transfer of charges at the photoelectrode/electrolyte interface. The electrochemical impedance study and Mott-Schottky supported these results. Moreover, during photoelectrochemical reactions, H-ZIS/CN nanocomposites showed tremendous stability under visible light. A potential mechanism of the enhanced photoelectrochemical activity of H-ZIS/CN nanocomposites was proposed and endorsed by the PEC results. This study demonstrates that establishing a heterostructure system by coupling a ternary chalcogenide semiconductor with a conducting polymer is an effective strategy for PEC water splitting applications. 相似文献
20.
Constructing heterostructures with narrow-band-gap semiconductors is a promising strategy to extend light absorption range of graphitic carbon nitride (g-C3N4) and simultaneously promote charge separa-tion for its photocatalytic activity improvement.However,its highly localized electronic states of g-C3N4 hinder photo-carrier migration through bulk towards heterostructure interfaces,resulting in low charge carrier separation effidency of solid bulk g-C3N4-based heterostructures.Herein,porous g-C3N4 (PCN)material with greatly shortened migration distance of photo-carriers from bulk to surface was used as an effective substrate to host CdSe quantum dots to construct type Ⅱ heterostructure of CdSe/PCN for pho-tocatalytic hydrogen production.The homogeneous modification of the CdSe quantum dots throughout the whole bulk of PCN together with proper band alignments between CdSe and PCN enables the ef-fective separation of photo-generated charge carriers in the heterostructure.Consequently,the CdSe/PCN heterostructure photocatalyst gives the greatly enhanced photocatalytic hydrogen production activity of 192.3 μmol h-1,which is 4.4 and 8.1 times that of CdSe andPCN,respectively.This work provides a fea-sible strategy to construct carbon nitride-based heterostructure photocatalysts for boosting visible light driven water splitting performance. 相似文献
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