Visible Light-driven Photocatalyst Research Articles

Physical properties and photocatalytic activity of Cr doped TiO2 nanoparticles.

Nanocrystalline Ti1-x Crx O2 (0≤ x ≤0.20) samples are synthesized via acid-modified sol-gel process and characterized with various techniques, such as HRTEM, FESEM, Raman, XPS, DTA and VSM. The TEM image of TiO2 exhibits elongated nanoparticles with an average size of 10 nm. The HRTEM in combination with selected area electron diffraction (SAED) patterns reveals the interplanar spacing and polycrystalline nature of the samples, respectively. FESEM micrographs reveal non-uniform morphologies and less aggregation of the particles in the doped sample. Raman spectra ensure the phase purity of the samples and a blue shift on Cr doping. X-ray photoelectron spectra (XPS) predict the chemical state of the elements and oxygen vacancies in the prepared samples. The room temperature magnetic studies reveal a significant variation in the magnetic parameters on Cr doping in TiO2 . The differential thermal analysis (DTA) shows the structural phase transition at ∼630°C. The photocatalytic performance is studied for the degradation of methylene blue (MB) dye under visible-light irradiation. A higher photocatalytic efficiency is found for the 20% of Cr-doped TiO2 . These studies propose that the appropriate incorporation of Cr ions makes TiO2 very efficient for visible light-driven photocatalysts required for applications in wastewater treatment. In the present study, nanoparticles of TiO2 and Cr doped TiO2 by a cost-effective acid-modified sol-gel process. The effect of Cr doping on the microstructure, thermal, magnetic and photocatalytic properties of TiO2 were explored in detail. The transmission electron microscopy (TEM) images exhibit the presence of elongated nanoparticles with an average size of 10 nm. Field emission scanning electron microscopy (FESEM) was used to study the surface morphology of the synthesized materials, which revealed non-uniform morphologies and less aggregation of the particles in the Cr-doped sample. Energy dispersive x-ray spectroscopy (EDS) confirms the elemental compositions with the appropriate stoichiometry of the elements. Raman spectra ensure the phase purity of the materials and also a blue shift with the incorporation of Cr ions in TiO2 . X-ray photoelectron spectra (XPS) predict the chemical state of the elements and oxygen vacancies in the prepared samples. The magnetic nature of all the synthesized samples was examined through the vibrating sample magnetometer (VSM) and revealed weak ferromagnetic behavior of the samples. These results signify that the oxygen vacancies and defects play a crucial role in developing the ferromagnetic nature of oxide semiconductors. The differential thermal analysis (DTA) shows the structural phase transition at ∼630°C. The photocatalytic performance of the prepared samples was studied for the degradation of methylene blue (MB) dye under irradiation of visible light. A higher photocatalytic efficiency was found for the 20% of Cr-doped TiO2 . These studies propose that the appropriate incorporation of Cr ions makes TiO2 very efficient for visible light-driven photocatalysts required for applications in wastewater treatment. This article is protected by copyright. All rights reserved.

Constructing AgBr/BiOBr@silkworm cocoons photocatalytic degradation and antibacterial material: Based on the excellent adsorption properties of silkworm cocoons

The silkworm cocoon (SC) possesses excellent adsorption performance due to the specific composite structure. Silk fibroin, the main component of SC, possesses lots of functional groups which are suitable for attachment of ligands, it plays an important role in the adsorption and chelation of metal ions, thus making SC a meaningful carrier. As a result, SC exhibits the best adsorption effect on Malachite green (MG), reaching 86.8% within 3 h in the present work. Additionally, AgBr/[email protected] visible light-driven (VLD) photocatalyst was successfully fabricated by ultrasound-assisted impregnation method with AgBr/BiOBr as a model and SC as a support. AgBr/[email protected] showed a remarkable photocatalytic degradation rate for Rhodamine B (Rh B, 98.52%), MG (80.08%) and Tetracycline (TC, 70.92%) under 120 min irradiation. Besides, it displayed superior activity in Staphylococcus aureus (S. aureus) disinfection, and the antibacterial efficiency above 99% upon 20 min of visible-light irradiation. The outstanding photocatalytic and antibacterial properties were mainly attributed to intimate contact and matched energy band positions between AgBr and BiOBr, which efficiently produce more active e--h+ pairs, and availably restrict the recombination of photogenerated carriers. This work could arouse an increasing interest in designing more SC-based photocatalysts for wastewater treatment.

Two-dimensional g-GeC/PtSe2 van der Waals heterostructure: a visible light-driven direct Z-scheme photocatalyst for overall water splitting

The vertical stacking of different two-dimensional materials to construct van der Waals heterostructures (vdWHs) opens up a promising platform for designing high-efficiency photocatalysts. Direct Z-scheme heterostructures for photocatalytic dissociation have received much attention in recent years, in which charge carriers migrate directly between two semiconductors without redox mediators. Here, the electronic and optical properties as well as the solar-to-hydrogen conversion efficiency of g-GeC/ PtSe2 vdWHs are systematically investigated, especially for their high-efficiency visible-light water splitting catalyst features. Calculations show that the g-GeC/ PtSe2 vdWH is a semiconductor with an indirect band gap of 1.356 eV, featuring a type-II band alignment. The built-in electric field E int and band bending at the interface lead to a direct Z-scheme photocatalytic structure, and photocatalytic water splitting can be realized in the pH range of 0–14. In particular, with biaxial tensile strain ϵ= 4% applied, the g-GeC/PtSe2 vdWH possesses a smaller band gap, wider visible light response range and very high STH conversion efficiency (η STH) up to 49.07%, entirely satisfying the optimal photocatalytic water splitting conditions. This work provides a new perspective for designing promising direct Z-scheme visible light water splitting catalysts with a high-efficiency solar energy conversion, beneficially to the development of clean energy.

Mutually supportive growth strategy to engineer a hollow biochar sphere-supported TiO2 composite with improved interfacial compatibility for efficient visible light-driven photocatalysis

Improving the interfacial compatibility between active components and support is significant and challenging. Herein, a mutually supportive growth strategy was created to engineer a Fe-Cu-doped hollow biochar sphere (HBS)-supported TiO2 (TiO2/Fe-Cu-HBS) composite with strong interfacial interaction via simultaneous growth of crystalline TiO2 and epitaxial carbonization of mechanical activation-treated starch-FeCl3-CuCl2. The TiO2/Fe-Cu-HBS composite with highly dispersed distribution and embedding of spherical TiO2 particles on the Fe-Cu-HBS shell had a narrow bandgap, favorable visible light capture and absorption capability, high separation efficiency of electron–hole pairs, and high transfer efficiency of photogenerated carriers. The superior photogenerated electron transport, high specific surface area, and enriched surface oxygen vacancies led to the generation of abundant reactive radicals on TiO2/Fe-Cu-HBS under visible light stimulation, contributing to efficient photocatalytic degradation of tetracycline hydrochloride (removal rate of 95.4% within 120 min; mineralization rate of 75.3% within 180 min), rhodamine B (removal rate of 99.2% within 100 min), and carbamazepine (removal rate of 67.5% within 120 min). Moreover, TiO2/Fe-Cu-HBS maintained high photocatalytic degradation efficiency after five cycles ascribed to its favorable structural stability. A mechanism of photocatalytic degradation of tetracycline hydrochloride and possible degradation pathways were proposed. This work provides a new growth strategy for constructing highly active and stable visible light-driven TiO2-based composite photocatalysts for effectively treating organic pollutants.

Bone powder decorated TiO2 and ZnO nanoparticles: The first investigation of NOx degradation by solar light and visible light-driven photocatalyst

This study performed the transformation of food waste and resin into the valuable photocatalyst which was applied in the NOx decomposition. Bone waste was used as the agricultural waste because of its high CaCO3 compositions. In this study, heterojunction composites were synthesized by calcination ZnO and TiO2 with chicken bone and pork bone (ZnO@Pb, ZnO@Cb, TiO2@Pb and TiO2@Cb). The degradation of NOx can be obtained from 63.30% to 81% under solar light irradiation from the concentration of NOx at 550 ppb. TiO2 decorated with pork bone under visible light gives the best NOx removal efficiency at 70%, with the concentration of NOx at 1800 ppb (1.8 ppm). Furthermore, the trapping experiments confirm that h+ and e− have an impact on the degradation of NOx. The addition of bone waste also shortened the band gap of TiO2/ZnO from 0.649 to 1.266 eV with the microcube formation. This study provides important information on cost-less catalysts for degrading nitrogen oxide (NOx) under solar light and visible light.

Atomic Nickel on Graphitic Carbon Nitride as a Visible Light-Driven Hydrogen Production Photocatalyst Studied by X-ray Spectromicroscopy

The photocatalytic production of solar hydrogen through water splitting by graphitic carbon nitride (g-C3N4) has gained substantial interest due to its advantageous characteristics, such as eco-friendliness, wealth on the earth, favorable bandgap, and easy preparation. Nevertheless, the performance for photocatalytic overall water splitting has been significantly restricted owing to the rapid recombination of charge carriers and slow catalytic kinetics. This investigation demonstrates the utilization of a single-atom Ni-terminating agent to coordinate with the heptazine moieties of g-C3N4, resulting in the formation of a new electronic orbital. g-C3N4 with single-atom Ni-termination can achieve highly efficient photocatalytic overall water splitting into H2 and H2O2 upon visible light irradiation, without requiring the use of any additional cocatalysts. The underlying cause of the enhanced photocatalytic performance of single-atom Ni-incorporated g-C3N4 in hydrogen evolution reaction is identified using synchrotron X-ray spectroscopy and microscopy. The X-ray spectro-microscopic results discover that the new hybrid orbital that is critical for optimizing photocatalysis is associated with carbon defects. The atomic and electronic structures and the band gap of g-C3N4 are adjusted by the new hybrid orbital. Moreover, it synergistically enhances visible light absorption, thereby promoting the separation and transfer of photogenerated charge carriers. The single-atom Ni and the adjacent C atom are recognized as the active sites for water oxidation and reduction, respectively, supporting the efficient photocatalytic splitting of water via a two-electron transfer pathway. This study demonstrated a promising material design for promoting photocatalytic activity in solar energy conversion applications.

Construction of a N−Mo−O bond bridged MoO2/Mo-doped g-C3N4 Schottky heterojunction composite with enhanced interfacial compatibility for efficient photocatalytic degradation of tetracycline

To improve the photocatalytic performance of g-C3N4 (CN), mechanical activation (MA) treatment of precursor followed by calcination was developed to construct a N−Mo−O bond bridged MoO2/Mo-doped CN (MA-MoO2/Mo-CN) Schottky heterojunction composite, which was used as a visible light-driven photocatalyst for degrading tetracycline (TC). The as-prepared MA-MoO2/Mo-CN with strong interfacial interaction showed excellent photocatalytic performance and structural stability, with 92.3% of TC degradation efficiency within 90 min and maintaining over 90% of degradation efficiency after five consecutive cycles. The enhanced photocatalytic performance can be ascribed to that MA treatment induced the improvement of surface area and the formation of N vacancies and N−Mo−O bonds, which served as a bridge to connect Mo-CN and MoO2 for constructing a Schottky barrier. These provided more reactive sites and effectively enhanced migration efficiency of interface electrons, separation efficiency of photogenerated carriers, and light absorption capacity. In addition, the mechanism of photocatalytic degradation of TC and its possible degradation pathway were investigated. This research provides an environmentally friendly and feasible method for producing highly active precious metal-free photocatalysts with excellent migration and separation efficiency of photoexcited charge carriers.

Magnetic and structural characterization of Sn doped cobalt ferrites; A visible light-driven photocatalysts for degradation of rhodamine-B and modeling the process by artificial intelligence tools

Tin (Sn) substituted cobalt ferrites Co1−xSnxFe2O4 with composition (x = 0.0, 0.1, 0.2, 0.3, 0.4 and 0.5) were synthesized utilizing sol-gel auto combustion method. All synthesized powders were characterized for their structural, magnetic and optical characterization after calcination. The single phase spinel with good crystallisation and a decreasing crystallite size with Sn substitution is confirmed by the powder X-ray diffraction (XRD) pattern. The magnetic measurements were carried out at room temperature where saturation magnetization values show sufficient magnetic nature of calcinated ferrites. The bandgap values for pure cobalt and Sn-substituted cobalt ferrites were closer to the experimental value. The visible light photocatalytic degradation of Rhodamine B was carried out in presence of Sn substituted cobalt ferrites that shows good catalytic activity up to 87% degradation for Co0.5Sn0.5Fe2O4 catalyst. Additionally, this study used Artificial Neural Network (ANN) and Adaptive Neuro-Fuzzy Interface System (ANFIS) models to simulate degradation efficiency with inputs including time, pH, and catalyst dosage. The results revealed that the 3–2–2–1 structure ANN4 model outperformed the other ANN and ANFIS models in the testing phase (RMSE = 6.90% and NSE = 0.92). According to the findings of this study, artificial intelligence models are capable of precisely predicting Rhodamine B degradation.

Synthesis and Characterization of Z-Scheme Heterojunction CoWO4/RGO/g-C3N4 as a Visible Light-Driven Photocatalyst for Novel Removal of Organic Pollutant

In this study, novel Z-scheme heterojunction photocatalyst CoWO4/RGO/g-C3N4 was successfully fabricated by a facial hydrothermal. Obtained morphology and topography studies indicated that deposition of reduced graphene oxide (RGO) and CoWO4 nanoparticles did not affect the structure of g-C3N4 sheets. However, optical results showed that visible light absorption of the material was significantly improved. The synthesized heterojunction photocatalyst exhibited improved photocatalytic performance in the novel degradation of rhodamine B, even upon visible irradiation. The improved photocatalytic performance was ascribed to interfacial contact between g-C3N4 and CoWO4 in a Z-scheme heterojunction in which RGO served as electron mediator accelerating its transfer between g-C3N4 and CoWO4 to minimize recombination of photogenerated electron-hole pairs. Therefore, rhodamine B degradation by CoWO4/RGO/g-C3N4 was 1.87 times higher than pristine g-C3N4. The synthesized heterojunction was relatively stable with no distinct reduction in photocatalytic activity after three recycling runs. The fabrication of heterojunction CoWO4/RGO/g-C3N4 is an efficient strategy to develop high-performance photocatalysts for various photocatalytic applications.

Efficient photocatalytic degradation of high-concentration moxifloxacin over dodecyl benzene sulfonate modified graphitic carbon nitride: Enhanced photogenerated charge separation and pollutant enrichment

Photocatalysis technology has been proved to be a promising strategy to eliminate antibiotic pollution from wastewater, in spite of arduous challenges such as insufficient utilization of sunlight, high recombination of photogenerated charges, low efficiency of high-concentration antibiotics, and infrequent investigation on new antibiotics. Herein, we synthesized a visible-light-driven (VLD) photocatalyst by modifying dodecyl benzene sulfonate (DBS) onto graphitic carbon nitride nanosheet (CNNS), and studied its photocatalytic performance for removing high-concentration moxifloxacin (MOX), a fourth-generation quinolone antibiotic. Compared with other studies (Table S1), this catalyst broke through the bottleneck of degradation of high concentration MOX, which could remove 100 mg L−1 MOX under 30 min of irradiation. The hydrophobic dodecyl benzene group and the formed sulfonyl group with strong electron-withdrawing property were beneficial to boost the MOX enrichment from the bulk solution and suppress the recombination of photogenerated charges. The effect of pH value, MOX concentration and photocatalyst dosage was also studied in order to explore the best photocatalytic reaction condition. The superior photocatalytic durability and practical application prospects of DBS/CNNS were also demonstrated. By revealing the band structure of the DBS/CNNS hybrid, as well as the active species and the intermediate products generated in the photocatalytic process, a plausible photocatalytic mechanism was proposed. This study indicates that the DBS/CNNS hybrid is a potential VLD photocatalyst for efficient elimination of high-concentration antibiotics in wastewater.

Three-dimensional ordered microporous silica supported p-lanthanum ferrite and n-ceria as heterojunction photocatalyst to activate peroxymonosulfate for bisphenol a degradation

In this study, three-dimensional ordered microporous silica supported p-lanthanum ferrite and n-ceria (n-CeO2@p-LaFeO3/3DOM SiO2) was successfully synthesized as a visible light-driven photocatalyst for activating peroxymonosulfate (PMS) to degrade Bisphenol A (BPA). In a wide pH range (2–12), the BPA degradation efficiency maintained at a high level, organic matter and natural inorganic ions had no significant negative impact. When the BPA concentration was as low as 2 mg·L−1, the removal rate in 60 min still reached 95.56%, indicating that the novel photocatalyst has potential application in the treatment of trace pollutants. The pore confinement effects of catalysts and the synergistic effect between LaFeO3 and CeO2 result in the excellent photocatalytic performance. We proposed the possible mechanism of BPA degradation, specifically involving the recognition and generation mechanism of reactive oxygen species (ROSs), adsorption processes and diffusion processes. In summary, the novel n-CeO2@p-LaFeO3/3DOM SiO2 would be a promising candidate photocatalytic material for practical sewage treatment.

Cu-Doped ZnIn2S4/NixP Composites with Enhanced Carrier Dynamics and Photocatalytic Hydrogen Production Performance

Photocatalytic technology still faces enormous challenges to design and synthesize highly efficient photocatalytic materials with a high electron/hole separation efficiency, rapid charge migration, low carrier recombination rate, and strong visible light-harvesting capability. Herein, Cu-doped ZnIn2S4/NixP (marked CuyZIS/NP) composites were successfully synthesized by a simple two-step method. The synergistic effect of Cu2+ doping and the NixP cocatalyst on hydrogen evolution performance was investigated in detail. The results showed that superior photoactivity over CuyZIS/NP composites was achieved. The optimal Cu0.5ZIS/NP-1/2 sample had a hydrogen evolution rate of 4746.3 μmol·g–1·h–1 under visible light irradiation, which was approximately 15.98 times higher than that of pure ZnIn2S4 (297 μmol·g–1·h–1). This work may offer a valuable insight into understanding the synergistic effect of doping and cocatalysis and provide a guideline for designing and developing highly efficient visible light-driven photocatalysts toward a water splitting system.

Catalyst-free biphasic orthorhombic/hexagonal tungsten oxide system with enhanced photocatalytic response under visible light

Abstract These days, textile industries pose a more significant threat to surface water and groundwater sources directly or indirectly by discharging wastewater containing various dyes and organic pollutants to these water sources. The phase-junction-engineered heterogeneous photocatalysis carried out by visible light-driven semiconductor photocatalysts is opening a new window for the degradation of environmental organic pollutants. In this work, we have reported a one-step bottom-up hydrothermal synthesis of biphasic tungsten oxide (o/h-WO3) and performed a photodegradation experiment under visible light irradiation for the efficient degradation of organic pollutants such as Methylene blue (MB) and Methyl violet (MV), respectively. The X-ray diffraction, RAMAN, transmission electron microscopy and ultraviolet–Vis characterization techniques were used to investigate the structural, morphological and optical properties of the as-synthesized o/h-WO3. Moreover, the low calculated band gap (∼2.8 eV) and the anionic nature of o/h-WO3 suggest it as an efficient visible light-driven photocatalyst suitable for heterogeneous photocatalysis. The photodegradation experiment performed under visible light using o/h-WO3 photocatalyst showed better degradation efficiency of 71% and 89% for MB and MV, respectively, in 100 min. The dyes followed first-order kinetics, and their kinetic rate constants were calculated using the Langmuir–Hinshelwood model. Furthermore, the recyclability study of the photocatalyst was also performed and discussed the underlying mechanism for the photodegradation of the organic dyes.

Development of visible light-driven SrTiO3 photocatalysts for the degradation of organic pollutants for waste-water treatment: Contrasting behavior of MB & MO dyes

Semiconductor photocatalysts were utilized widely for degrading organic pollutants in water using the advanced, environment-friendly, low-cost, and highly efficient photocatalysis technique. There are various complex energy-consuming techniques used for the refinement of wastewater. However, the photocatalysis process is the cleanest technique used for degrading organic pollutants in wastewater into the water; carbon dioxide, other small molecules, and inorganic pollutants were reduced or oxidized into harmless substances.SrTiO3 nanoparticles (NPs) synthesized by the chemical method are the topic of attention among researchers because of their physical, chemical & photocatalytic properties under sunlight for water purification applications. This paper dealt with the study of The photocatalytic properties of SrTiO3 and its composites under sunlight irradiation. Here, we evaluated the photodegradation of methyl orange (MO) and methylene blue (MB) pollutants using SrTiO3 as a photocatalyst for de-ionized (DI) water and hard water, respectively. Later on, the ex-situ decoration of Ag and Au nanoparticles (NPs) on SrTiO3 NPs results in enhancing the photocatalytic activity of SrTiO3. This article shows the abnormal behaviour of MO degradation compared to MB dye because there was no degradation of methyl orange for both bare SrTiO3 and Ag, Au@SrTiO3 nanocomposites. However, for bare-SrTiO3, the photocatalytic degradation of MB dye for de-ionized and hard water was accomplished in 210 min and 300 min, respectively. Here, SrTiO3 with MB dye shows enhanced photocatalytic activity for de-ionized water than hard water, and thus we determined the degradation of SrTiO3 nanocomposites with DI water only. While in the case of SrTiO3 nanocomposites, degradation occurred in 210min for Ag and 180 min for Au in DI water which signifies that Au a better co-catalyst for photodegradation. Although, degradation of MO in both DI water and hard water does not show any photocatalytic activity even in 6 and 7 h, respectively, for bare SrTiO3 and its nanocomposites. Therefore, it gives an idea about the different behaviour of dyes in photocatalytic degradation of DI and hard water using bare SrTiO3 and noble metal doped SrTiO3 as photocatalysts for water remediation applications.At a glimpse, this work focus on the photocatalytic removal of various water pollutants using the efficient noble metal (Au & Ag) doped SrTiO3 as a photocatalyst and discusses the properties of those materials and also discuss the prospects for the utilization of those photocatalysts in complex form for the wastewater treatment.

Rapid and facile synthesis of Z-scheme ZnO/g-C3N4 heterostructure as efficient visible light-driven photocatalysts for dye degradation and hydrogen evolution reaction

The coupling of two-different semiconductors which are photocatalytically active is gaining popularity in recent years because the heterojunction can decrease the rate of recombination of photoexcited electron-hole pairs and enhance the photocatalytic activity. In the current work, ZnO/g-C3N4 heterojunction hybrids have been generated by simple solution mixing of the dispersed ZnO and graphitic carbon nitride (g-C3N4) nanoparticles. The ZnO/g-C3N4 composite under visible light exhibits 91.5% degradation of the methylene blue (MB) dye in 120 min and also demonstrated excellent cyclic stability. Mechanistic studies and dye degradation experiments carried out in the presence of scavengers (ascorbic acid, potassium dichromate and ammonium oxalate) revealed that the generated superoxide radical (O2•‒) and hydroxyl radicals play a crucial role in MB dye degradation using ZnO/g-C3N4 as a photocatalyst. Further, the ZnO/g-C3N4 composite exhibits improved hydrogen evolution reaction (HER) activity (1358 μmol g-1 h-1) compared to the pristine ZnO nanoparticles (545 μmol g-1 h-1) and g-C3N4 (238 μmol g-1 h-1). The superior HER activity of the hybrid is ascribed to the increased charge-transfer rate owing to the better interfacial contact between the heterocomponents. Secondly, the nanoparticle nature of ZnO and g-C3N4 heterocomponents provides more exposed edge sites and thereby gives significant photocatalytic activity.

Cost-effective preparation of layered tantalum oxynitrides for visible light-driven photocatalysis.

Layered oxynitrides are promising materials for visible light photocatalysis. However, the conventional method for the synthesis of oxynitrides using ammonia as a nitrogen source is dangerous. In this work, we successfully synthesized two layered tantalum oxynitrides, K1.35LaTa2O6.65N0.35 and K1.4Ca2Ta3O9.6N0.4, via a topochemical nitridation process using urea as a solid nitrogen source. Employing different characterization methods, we determined the structure and composition of layered oxynitrides. Furthermore, using Pt as a co-catalyst, these two layered oxynitrides showed excellent photocatalytic performances under visible light irradiation. In contrast to ammonia, urea process provides easy access for the synthesis of layered oxynitrides and sheds new light on the design of effective visible light-driven photocatalysts.

Z-scheme CeO2/Ag/CdS heterojunctions functionalized cotton fibers as highly recyclable and efficient visible light-driven photocatalysts for the degradation of dyes

High-performance photocatalysts with excellent recyclability are viewed as promising materials for dye-contaminated wastewater remediation. In this work, novel Z-scheme CeO2/Ag/CdS ternary heterojunction composites were successfully prepared, which exhibited high photocatalytic activity for efficient visible light-driven degradation of organic dyes, due to the effective charge transfer at the interface of the formed Z-scheme ternary heterojunction. Further, to endow photocatalysts with the facile recyclable feature, the CeO2/Ag/CdS heterojunctions functionalized cotton fibers (CeO2/Ag/CdS-CF) were fabricated based on the “active ester-amino” chemical reaction via utilization of pentafluorophenyl esters. The results presented that the as-prepared CeO2/Ag/CdS-CF had superior photocatalytic activity towards dyes, which could remove 89.4% of methylene blue (MB) under visible-light irradiation for 180 min. Additionally, the CeO2/Ag/CdS-CF showed outstanding recyclability and long-term stability with the MB degradation efficiency remaining above 82.3% even after 5 successive cycles. Overall, this work not only provides a highly visible light active CeO2/Ag/CdS-CF system for dye wastewater treatment but also contributes to developing a versatile method to prepare facile recyclable photocatalysts.

Hot Electron-Driven Photocatalysis Using Sub-5 nm Gap Plasmonic Nanofinger Arrays.

Semiconductor photocatalysis has received increasing attention because of its potential to address problems related to the energy crisis and environmental issues. However, conventional semiconductor photocatalysts, such as TiO2 and ZnO, can only be activated by ultraviolet light due to their wide band gap. To extend the light absorption into the visible range, the localized surface plasmon resonance (LSPR) effect of noble metal nanoparticles (NPs) has been widely used. Noble metal NPs can couple incident visible light energy to strong LSPR, and the nonradiative decay of LSPR generates nonthermal hot carriers that can be injected into adjacent semiconductor material to enhance its photocatalytic activity. Here we demonstrate that nanoimprint-defined gap plasmonic nanofinger arrays can function as visible light-driven plasmonic photocatalysts. The sub-5 nm gaps between pairs of collapsed nanofingers can support ultra-strong plasmon resonance and thus boost the population of hot carriers. The semiconductor material is exactly placed at the hot spots, providing an efficient pathway for hot carrier injection from plasmonic metal to catalytic materials. This nanostructure thus exhibits high plasmon-enhanced photocatalytic activity under visible light. The hot carrier injection mechanism of this platform was systematically investigated. The plasmonic enhancement factor was calculated using the finite-difference time-domain (FDTD) method and was consistent with the measured improvement of the photocatalytic activity. This platform, benefiting from the precise controllable geometry, provides a deeper understanding of the mechanism of plasmonic photocatalysis.

TiO2/BiVO4 nanofibers: visible light-driven photocatalysts for indigo dye remediation

TiO2/BiVO4 nanofibers: visible light-driven photocatalysts for indigo dye remediation

NiFe2O4 nanoplates decorated on MoS2 nanosheets as an effective visible light-driven heterostructure photocatalyst for the degradation of methyl orange

NiFe2O4 nanoplates decorated on MoS2 nanosheets as an effective visible light-driven heterostructure photocatalyst for the degradation of methyl orange