BiOCl/diatomite composite with enhanced photocatalytic property for the degradation of liquid Tetracycline hydrochloride (TC) and gaseous formaldehyde (HCHO) were successfully prepared by a facile hydrothermal method at different pH value. The structure and morphology characterizations of BiOCl/diatomite composite exhibit that diatomite not only acts as a natural porous support of photocatalyst but also acts as dominant facets regulator at pH = 3 when the doping amount is change, owing to the surface electrical property of the diatomite and interaction between diatomite and BiOCl. This interaction is certified by XPS and FT-IR which indicate that Bi in layer structure of [Bi2O2]2+ group interacts with the O in SiOSi bond when the formation of BiOCl with the participation of diatomite. The BET characterization confirms that the increasing amount of diatomite enables the composite with more reaction points for light harvest and molecule adsorption than pure BiOCl. Furthermore, TC and formaldehyde are targeted as degradation objects to test the photocatalytic property of BiOCl/diatomite composite. The optimum photocatalytic property are BiOCl(3–1.2) and BiOCl(12–0.6) at TC degradation and BiOCl(3–0.3) and BiOCl(12–0.6) at formaldehyde elimination, which is much better than that of pure diatomite or BiOCl. The difference of optimum photocatalysts in liquid and gaseous phase systems can be attributed to the photoelectric performances of BiOCl/diatomite composite, which were characterized by DRS, PL, transient photocurrents and the electrochemical impedance spectroscopy technique. 相似文献
AgI/BiOCOOH composite photocatalysts have been synthesized via a simple deposition-precipitation method. The crystal structure, microstructure, element valance, light and electrical properties of as prepared samples were characterized by XRD, SEM, TEM, XPS, UV–Vis DRS, PL, EIS and photocurrent response. The loading of AgI nanoparticles endowed BiOCOOH with good visible light absorption and photocatalytic activity for degrading rhodamine B. The composition with Ag:Bi?=?1:1 exhibited the best photocatalytic activity. The enhanced photocatalytic performance could be mainly attributed to the effective separation of the photogenerated carriers at the heterojunction. O2? and h+ were suggested as the main reactive species in the photocatalytic reaction. In addition, the photocatalysts showed excellent stability over multiple reaction cycles. 相似文献
BiOBr and BiOCl were decorated on TiO2 QDs through n-p-p heterojunctions by a simple strategy and they were applied for degradation of three organic dyes upon visible illumination. The obtained photocatalysts were analyzed via XRD, FESEM, EDX, UV–vis DRS, PL, BET, TEM, HRTEM, FT-IR, EIS, XPS, and transient photocurrent measurements. The TiO2 QDs/BiOBr/BiOCl nanocomposite with 20% wt. of BiOBr and 30% wt. of BiOCl displayed superior photoability in the degradation of methylene blue, rhodamine B, and fuchsine, which was almost 34.5, 176, and 78.7-times larger than TiO2 and 27.8, 13.5, and 51.5-folds greater than TiO2 QDs, respectively. The results show that the construction of intimate n-p-p heterojunctions between BiOBr, TiO2 QDs, and BiOCl counterparts leads to enhanced visible-light harvesting and improved charge separation, resulted efficiently increased photocatalytic activity. The trapping results proved that h+, •O2−, and OH• species have considerable effects on the degradation reaction. We think that the improved efficiency of the ternary TiO2 QDS/BiOBr/BiOCl photocatalyst is a splendid alternative for the removal of toxic contaminants from wastewater. 相似文献
Introduction of oxygen vacancies (OVs) on the surface of photocatalyst has been proved to be a potent avenue to improve photocatalytic capability by accelerating the segregation of photoactivated carriers and creating a defect energy level. In this presentation, a facile hydrothermal approach was performed to fabricate polyphenylene sulfide (PPS)/OVs-BiOCl composites to further improve the catalytic capability of OVs enriched BiOCl. The successful construction of rich OVs in BiOCl was firmly confirmed by X-ray photoelectron spectroscopy (XPS) and low- temperature electron spin resonance (ESR). Surface photovoltage spectrum (SPS) and electrochemical characterization display that the existence of PPS in the synthetic system dramatically affects the surface states of BiOCl, expediting the segregation of photoinduced carriers. Photocatalytic capacity of PPS/OVs-BiOCl was examined by disintegration of perfluorooctanoic acid (PFOA), rhodamine B (RhB) and tetracycline (TC). PPS surface modification can significantly improve the photoactivity of OVs-BiOCl toward destruction of PFOA, RhB and TC. Interestingly, when mass ratio of PPS/BiOCl is 0.5%, the degradation capacity of PPS/OVs-BiOCl for decontamination of RhB and TC is 4.25 and 3.10 -fold higher than that of OVs-BiOCl, respectively. In consideration of the observations, the photocatalytic enhancement mechanism for PPS/OVs-BiOCl was elaborated. 相似文献
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.
Plasmonic photocatalysts are promising candidates for use in the degradation of pollutants. Their ability to degrade a wide range of organic pollutants stems from key properties such as high visible light absorption, the ability to generate hot electrons and the formation of a Schottky barrier that facilitates effective separation of charge carriers. In the present work, we synthesised bismuth oxychloride sensitised with gold nanoparticles (NPs, 20–50 nm) via a two-step chemical process at low temperature. The fabricated Au/BiOCl powder was evaluated in the degradation of Rhodamine B (RhB) dye under visible light irradiation. The photocatalytic performance of the Au/BiOCl hybrid was almost double that of pristine BiOCl. This enhanced performance was attributed to electron transfer from BiOCl to Au via the formation of heterojunctions at the BiOCl/Au interface. Additionally, the surface plasmon resonance effect of the Au NPs provided high optical absorbance in the visible spectrum. TEM (transmission electron microscopy) analysis indicated the presence of polar (010) facets on the BiOCl sheets, which also contributed to dramatically improving their photocatalytic performance. The degradation time of the Au/BiOCl hybrid was 200 min compared with 320 min for pure BiOCl. 相似文献
Constructing heterojunctions is an excellent way to enhance the photocatalytic property of semiconductors. Herein, a range of S-scheme BiOCl/g-C3N4 heterojunctions with varying mass ratios were designed using a facile hydrothermal route, and their photocatalytic ability was assessed by degrading the ethyl xanthate (EX) under visible light (λ > 400 nm). The results showed that the degradation efficiency of BiOCl/g-C3N4-0.1 heterojunction for EX was up to 91.2 % within 180 min, and its apparent rate constants (Kapp) were 4.3 and 11 times greater than those of BiOCl and g-C3N4, respectively. The experimental and characterization results revealed that the excellent photocatalytic property was ascribed to the construction of S-scheme heterojunctions. Such structure not only enhanced the visible light response but also facilitated the efficient separation of photoinduced carriers with the S-scheme transfer route, retaining strong redox-capable holes and electrons to participate in surface reactions. Furthermore, the cycling experiments indicated that the fabricated photocatalysts have great recyclability and stability. Based on the results of active substance capture, the S-scheme charge transfer model was proposed and the photodegradation mechanism of EX was reasonably elucidated. Overall, this work offers some theoretical direction for the design and construction of S-scheme heterojunctions with superior visible-light-driven photocatalytic performance. 相似文献
Sn-doped BiOCl (Sn/BiOCl) photocatalysts were synthesized by a precipitation method using Bi(NO3)3?·?5H2O as a bismuth source, SnCl2 as an Sn source, imidazole hydrochloride as a chlorine source, a solvent, and a template agent. The photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy, surface area analysis (Brunauer, Emmett and Teller [BET]), and diffuse reflectance spectroscopy. The XRD results showed a greater increase in the peak intensity of Sn/BiOCl because of its high degree of crystallinity. The UV–Vis results indicated a redshift from 368?nm (BiOCl) to 418?nm (Sn/BiOCl), leading to the reduced band gap of BiOCl because of Sn doping in BiOCl. The Sn/BiOCl not only retained ultraviolet photocatalytic activity of BiOCl but also showed visible photocatalytic activity. The BET results showed that the surface area of Sn/BiOCl (23.35?m2?) was bigger than that of BiOCl (13.54?m2?g). The bigger surface show higher photocatalytic activity due to more contact opportunity between reactants. Hence, the increased photocatalytic activity of Sn/BiOCl in the degradation of rhodamine B can be attributed to a higher degree of crystallinity, larger surface area, and broader range of optical absorption. The Sn/BiOCl needed only 20?min under visible light and 40?min under ultraviolet light to completely degrade rhodamine B. Moreover, the photocatalytic experiment did not require any other chemical reagent such as H2O2. The microstructures of BiOCl and Sn/BiOCl ensured that the catalyst still has high recovery rate when it is reused. The microstructures of catalyst have a little of loss. 相似文献
Herein, a novel CoTiO3/BiOI (CTOB) p-n heterojunction with nanosheets-on microrods structure were prepared via a simple coprecipitation method for the first time. The catalysts were carefully characterized by various instruments. The CTOB heterostructures display improved photocatalytic performance towards RhB degradation. Among CTOB composites, CTOB-15 exhibits the optimal photocatalytic performance. Moreover, CTOB-15 also shows enhanced photocatalytic activity for MO and TC degradation compared to bare catalysts. The degradation rate constants for RhB and MO by CTOB-15 heterostructure are ca 1.6 and 1.4-fold higher than bare BiOI. The improved photocatalytic performance could be on account of the efficient separation of photoinduced carriers as well as enhanced light absorbance. Trapping experiments indicates that holes (h+) and superoxide anion radical (O2–) play a significant role in the removal of RhB by CTOB composites. The excellent photocatalytic activity and stability make it a promising photocatalyst in environmental remediation. 相似文献
Focussing on visible light active ferrites for high performance removal of noxious pollutants, we report the synthesis of Mg0.5NixZn0.5-xFe2O4 (x = 0.1, 0.2, 0.3, 0.4, & 0.5) ferrite nanoparticle for degradation of reactive blue-19 (RB-19). Lattice parameters calculated using intense X-ray diffraction (XRD) peaks and Nelson-Riley plots (N-R plot) are in well agreement with each other. The sample Mg0.5Ni0.4Zn0.1Fe2O4 (M5N4) exhibits best performance with 99.5% RB-19 degradation in 90 min under visible light. Photoluminescence (PL) results confirm that recombination of charge carriers is highly reduced in the photocatalyst. Scavenging experiments suggest that O2− radicals were the dominant species responsible for photocatalytic performance. The photocatalytic mechanism was explained in terms of dopant driven shifting of conduction bands and valence bands (calculated by Mott-Schottky plots). The thermodynamic probability of radical generation along with role of redox cycles of metal ions has been discussed in the mechanism. The dye degradation was ascertained by detection of intermediates via mass spectrometry analysis and a possible degradation route was also predicted. The findings in this work provide intriguing opportunities to modify the electronic band structure of spinel ferrites for visible and solar light photocatalytic activity for environmental detoxification. 相似文献
Visible light-active bismuth oxychloride–reduced graphene oxide (BiOCl–RGO) composite photocatalysts were synthesised using a hydrothermal method at low temperature, and at a low cost. This approach reduced the recombination of electron–hole pairs and thereby provided more efficient photocatalysts. The size of BiOCl structure was controlled by polyvinylpyrrolidone (PVP) addition. Furthermore, formation of nanosized BiOCl sheets and BiOCl–RGO composites were confirmed by X-ray diffraction, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. Fabricated BiOCl–RGO composite with PVP exhibited better photocatalytic activity than pure BiOCl grown with and without PVP towards degradation of Rhodamine B (RhB). It was found that the composite photocatalyst degrades RhB completely within 310 min as compared with several hours for pure BiOCl. The improved photocatalytic performance of BiOCl–RGO composite was attributed to its high specific surface area (22.074 m2 g?1 and existence of polar surfaces, compared with 9.831 m2 g?1 for pure BiOCl). The analyses indicated that RGO helped to reduce recombination losses and improve electron transport. It also showed that presence of polar surfaces improved photocatalytic activity of BiOCl. Hence, BiOCl–RGO composite is a promising catalyst for the degradation of organic pollutants under visible light and could be used in applications such as water purification devices. 相似文献
Ag/AgX (X?=?Cl, Br) plasmonic photocatalysts were synthesized via a facile one-pot ultrasonic spray pyrolysis method, wherein no additional issues such as high pressure, surfactants and reducing agents were required. The structure, morphology, and optical property of the as-prepared photocatalysts was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM), ultraviolet–visible light absorption spectra and total organic carbon (TOC). The results showed that Ag/AgX photocatalysts have excellent photocatalytic performance for the photodegradation of methyl orange (MO) and methylene blue (MB) pollutants under visible light illumination, and the photocatalytic activity maintains a high level after seven cycles. Metallic Ag0 particles nucleate on the surface of AgX uniformly through the thermal decomposition of residual AgNO3 solution, which enhanced the interaction between Ag0 and AgX. The outstanding photocatalytic activity benefits from the small size and high dispersion of Ag0 nanoparticles and the enhanced interaction between Ag0 and AgX. 相似文献
Nanoparticle photosensitizers possess technical advantages for photocatalytic reactions due to enhanced light harvesting and efficient charge transport. Here we report synthesis of semiconductor nanoparticles through covalent coupling and assembly of metalloporphyrin with condensed carbon nitride. The resultant nanoparticles consist of light harvesting component from the condensed carbon nitride and photocatalytic sites from the metalloporphyrins. This synergetic particle system effectively initiates efficient charge separation and transport and exhibits excellent photocatalytic activity for CO2 reduction. The CO production rate can reach up to 57 µmol/(gh) with a selectivity of 79% over competing H2 evolution. Controlled experiments demonstrate that the combination of light harvesting with photocatalytic activity via covalent assembly is crucial for the high photocatalytic activity. Due to effective charge separation and transfer, the resultant nanoparticle photocatalysts show exceptional photo stability against photo-corrosion under light irradiation, enabling for long-term utilization. This research opens a new way for the development of stable, effective nanoparticle photocatalysts using naturally abundant porphyrin pigments.
The g-C3N4/NaNbO3 photocatalyst was synthesized by simply calcining the mixture of NaNbO3 and melamine. The synthesized composite exhibits high photocatalytic performance in the selective oxidation of 5-Hydroxymethylfurfural (HMF) to 5-formyl-2-furancarboxylic acid (FFCA) when using water as solvent. The structure and composition of g-C3N4/NaNbO3 photocatalysts were characterized by TG, XRD, SEM, UV–Vis, FT-IR, and XPS methods, and the optical and electrochemical properties were investigated by EIS, PC, and PL techniques. O2− was inferred to be the primary active species in this process based on the active species trapping experiment. Heterostructure formation of g-C3N4/NaNbO3 composites efficiently promoted the separation of photo-generated electron-hole pairs and accelerated the electron transfer rate, thus reduced the formation of OH, and sequentially improved the selectivity of FFCA. The highest HMF conversion of 35.8% with FFCA selectivity of 87.4% was achieved on C/N-59.6 photocatalyst under the irradiation of visible light. The possible mechanism and reaction route were also proposed. 相似文献
In this work, we have employed melamine, cyanuric acid and thymine to fabricate triazine-based carbon nitrides (CNs) by supramolecular approach. The resultant CNs possess large specific surface area, hierarchical porous structure, better light absorption capacity and high separation rate of photoinduced carriers. Then, the photocatalytic reduction and oxidation performance has been evaluated. The obtained CNs exhibit enhanced photocatalytic reduction performance on water splitting to H2, the largest hydrogen evolution rate can reach 8466.3 μmol g?1 h?1, which is 81.9 times as high as that of bulk CN. Simultaneously, the porous CNs show excellent photocatalytic reduction ability on the conversion of CO2 to H2, CO and CH4. Of particular interest is that they have high selectivity for CO. It’s worth noting that the porous CNs also possess outstanding photocatalytic oxidation ability on high concentration nitric oxide (NO), and the highest NO conversion rate can reach 79.3% under visible light. The enhanced photocatalytic performance for the multifunctional porous CN can be ascribed to the synergic effect of large specific surface area, strong light absorption capacity and fast separation of photoinduced electron–hole pairs. Finally, the photocatalytic reduction and oxidation mechanism of the porous CN is also proposed and discussed. 相似文献
In this research, Bi4O5I2 and AgI nanoparticles were anchored over g-C3N4 nanosheets (denoted as NGCN/Bi4O5I2/AgI) to preparation highly impressive visible-light-driven samples. The synthesized nanocomposites were investigated by X-ray diffraction (XRD), Fourier transform-infrared (FT-IR), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), UV–vis diffuse reflectance spectroscopy (DRS), energy dispersive analysis of X-rays (EDX), electrochemical impedance spectroscopy (EIS), photocurrent density, Brunauer-Emmett-Teller (BET), and photoluminescence (PL) analyses. Among the ternary photocatalysts, the NGCN/Bi4O5I2/AgI (20%) photocatalyst illustrated the highest photoactivity in degradation of rhodamine B (RhB), which was approximately 58.4, 15.2, and 12.8 times higher than the GCN, NGCN, and NGCN/Bi4O5I2 (20%) samples, respectively. Furthermore, the O2− was discovered as the main species in the respective system by the quenching tests. Also, by studying the electrochemical properties, a cascade photocatalytic mechanism was suggested based on the energy bands to describe the enhanced charge carriers migration and separation, which caused impressive photocatalytic performances in degradations of four hazardous contaminants. This study highlights the rational anchoring of Bi4O5I2 and AgI nanoparticles over NGCN to prepare highly efficient photocatalysts for wastewater remediation. 相似文献