Photoinduced Holes Research Articles

Preparation of the self-accelerating photocatalytic self-cleaning carboxymethyl cellulose sodium-based hydrogel for removing cationic dyes

Hydrogels loaded with photocatalysts have shown great potential in effectively degrading dye wastewater. In this work, carboxymethyl cellulose sodium-based hydrogels loaded with nitrogen-doped graphene oxide-zinc oxide-zinc peroxide (NGO-ZnO-ZnO2) were synthesized using hydrothermal reaction and in-situ synthesis method. NGO acts as an electron mediator, suppressing the recombination of photoinduced electrons and holes. ZnO2 decomposes to generate hydrogen peroxide (H2O2), promoting a self-enhanced photocatalytic reaction. Carboxymethyl cellulose sodium (CMC) acts as a dispersant, improving the uniformity and stability of NGO-ZnO-ZnO2 within the hydrogel. The results demonstrate that NGO-ZnO-ZnO2 exhibits high photocatalytic degradation efficiency towards methyl orange (MO) (10 mg/L) and rhodamine B (RhB) (50 mg/L), with degradation rates of 99.99 % (200 min) and 99.26 % (160 min), respectively. The carboxymethyl cellulose sodium-based hydrogel achieves a photocatalytic degradation rate of 95.85 % (220 min) for RhB (10 mg/L). After 5 cycles of repeated photocatalytic tests, the degradation efficiency of the hydrogel towards RhB reaches 80.81 %. This work provides a low-cost and convenient method for constructing novel hydrogel carriers with high photocatalytic stability and efficiency.

Evaluation of the photodegradation activity of bismuth oxoiodide/bismuth sub-carbonate nanocatalyst: Experimental design and the mechanism study

In this study, a binary BiOI/(BiO)2CO3 catalyst was prepared and used for sulfasalazine (SSZ) photodegradation in an aqueous phase. The semiconductors were identified by XRD, SEM-EDX, and UV–Vis diffuse reflectance spectroscopy (DRS) methods. Applying the Kubelka-Munk model on DRS results, the band gap energies of 2.09, 3.5, and 2.07 eV were obtained for BiOI, (BiO)2CO3, and BiOI/(BiO)2CO3 samples. pHpzc values of 6.3, 10.1, and 8.1 were estimated for BiOI, (BiO)2CO3, and BiOI/(BiO)2CO3, respectively. After observing the boosted photocatalytic activity by the coupled system, the interaction effects of the influencing variables in SSZ photodegradation were evaluated via the response surface methodology (RSM) approach. The optimal RSM-run conditions were 8.5 ppm SSZ at pH 8, which contained 0.28 g/L of the BiOI/(BiO)2CO3 catalyst and 29 min illumination time, resulting in 87% SSZ photodegradation. The effects of some scavenging agents were also studied to elucidate the relative roles of the reactive species in the SSZ photodegradation by the proposed catalyst, that is, hydroxyl radicals ∼ photoinduced electrons > superoxide radicals ∼ photoinduced holes. The proposed catalyst retained good activity after 5 successive reusing runs.

Oxygen-modified graphitic carbon nitride with nitrogen-defect for metal-free visible light photocatalytic H2O2 evolution

Photocatalytic oxygen reduction is regarded as the cleanest approach for the production of hydrogen peroxide (H2O2). Herein, oxygen-modified graphite carbon nitride (g-C3N4) with nitrogen-defect (namely g-C3N4-ND4-OM3) was synthesized by a feasible method. Owing to the existence of nitrogen vacancy and oxygen-containing functional group, the absorption bands derived from n → π* and π → π* electronic transitions were enhanced, thereby enlarging the visible light response range of catalysts. Interestingly, nitrogen-defect can capture electron and effectively suppress the recombination of photoinduced electrons and holes. More importantly, the introduction of oxygen-containing functional groups can improve the hydrophilicity of g-C3N4, which was beneficial for the adsorption of dissolved oxygen. The electrostatic potential distributions of g-C3N4-based photocatalyst structural unit were also changed after introducing nitrogen vacancy and oxygen-containing functional group, and the electron-donating ability of g-C3N4 was improved. As a result, the evolution rate of H2O2 catalyzed by g-C3N4-ND4-OM3 was as high as 146.96 μmol/g/L under visible light irradiation. The photocatalytic H2O2 generation was completed through the direct 2-e− oxygen reduction. In short, current work will share novel insights into photocatalytic H2O2 generation over g-C3N4-based catalyst.

Effect of the halogen substitution on the interfacial properties of MAPbI3 (110)/Ti3C2T2 (001): First-principles calculations

To improve the optoelectronic properties and charge extraction efficiency of perovskite devices, precise device design and expert interface engineering are essential. In this study, we utilized first-principles simulations to investigate the structural, electrical, and optical characteristics of the interfaces between MAPbI3 and Ti3C2T2 (T = Cl, Br, I). Our computed charge density differences indicate that the internal electric field of MAPbI3/Ti3C2T2 promotes the transfer and separation of photoinduced electrons and holes. Furthermore, the heterostructures exhibit enhanced optical absorption, with higher absorption intensity observed in the visible band. Notably, the PbI2/Ti3C2Br2 interface shows the strongest cohesive energy, charge transfer, and optical absorption among the interfaces investigated. These findings provide detailed insights into the atomic-level interfacial properties of MAPbI3/Ti3C2T2 and offer valuable theoretical recommendations for the development of novel perovskite devices.

Construction of CdS@ZnO core–shell nanorod arrays by atomic layer deposition for efficient photoelectrochemical H2 evolution

Photoelectrochemical (PEC) water splitting provides a promising strategy for the production of clean hydrogen fuel. Herein, a new CdS@ZnO core–shell nanorod arrays (NRAs) is successfully constructed by atomic layer deposition (ALD) for H2 evolution from PEC water splitting. The CdS@ZnO200 obtained after 200 ALD cycles presents a significantly enhanced PEC H2 evolution rate of 21.64 μmol·h−1·cm−2, which is about 9.4 times of pristine CdS NRAs (2.31 μmol·h−1·cm−2). The reasons for the improved PEC H2 evolution performance can be ascribed to several aspects: firstly, the Z-scheme charge transfer mechanism formed between CdS core and ZnO shell promotes the effective spatial separation of photo-induced electrons and holes; secondly, the close contact between the two semiconductors resulted from ALD process helps to reduce the transfer resistance of charge carriers. In addition, the CdS core is tightly wrapped by ZnO shell, which helps to prevent the photo-corrosion of CdS core. This work provides a new type of photoanode material suitable for PEC H2 evolution from water splitting, and provides an efficient anti-corrosion method for the use of photocorrosive semiconductor materials.

Perovskite CuO@BaSnO3 nanorods photocatalysts with promoted visible light ability for desulfurization of thiophene

BackgroundThe desulfurization of fuels is critical to upgrade their performance and to match the demands of sulfur standards MethodMesoporous p-n heterojunctions CuO/BaSnO3 nanorods were fabricated by the hydrothermal process in the presence of polyvinylpyrrolidone. The photocatalytic performance of the synthesized CuO/BaSnO3 nanorods at various CuO percentages compared with the pristine BaSnO3 was evaluated by desulfurising thiophene under visible light illumination Significant findingsXRD and HRTEM results verified the fabrication of perovskite BaSnO3 in cubic structure and CuO in the monoclinic phase, and TEM images of CuO/BaSnO3 exhibited nanorod-like morphology with a length of 100 nm and width of 10 nm decorated with CuO NPs (5 nm). After optimization, the experimental results showed that with a photocatalyst dosage of 2 g/L and CuO percentage of 15%, the maximal desulfurization rate of thiophene was around 100% within 60 min. The rate constant of 15% CuO/BaSnO3 photocatalyst was the maximum, and it was enhanced larger 3.36 times than that of the pristine BaSnO3 nanorods. The photocurrent intensity of 15% CuO/BaSnO3 photocatalyst was enhanced 9.2 times greater than that of pristine BaSnO3. The enhancement of the desulfurization rate illustrated that the creation of an internal electric field through the p-n heterojunction CuO/BaSnO3 system could facilitate the separation of photoinduced holes and electrons, improving the charge transport ability and hence promoting the photocatalytic performance. PL, transient photocurrent responses and electrochemical impedance results were determined to confirm our photocatalytic results. Cycling runs displayed that the obtained CuO/BaSnO3 photocatalyst still exhibited high photocatalytic ability and stability after five cycles. This work is anticipated to strengthen the design of effective and novel p-n heterojunctions photocatalysts for practical photocatalysis applications in terms of H2 production and detoxification of toxic organic compounds.

Photocatalytic degradation of efavirenz and nevirapine using visible light-activated Ag-AgBr-LDH nanocomposite catalyst

Antiretroviral drugs (ARVDs) are one of the many classes of emerging pharmaceutical pollutants that have been detected in South African waterbodies in recent years. Efavirenz (EFV) and nevirapine (NVP) are commonly used drugs in antiretroviral therapy (ART) in the region and have been reported to be persistent in wastewater. Their presence in water poses health hazards to human beings and the aquatic environment. It is therefore important that these compounds be remediated from the environment. Visible light activated photocatalysis is one of the sustainable remediation technologies that aptly removes refractory organic contaminants from various water matrices. This study reports for the first time, the synthesis of silver halide doped Mg-Zn-Al LDH clay as a photocatalyst in the degradation of selected ARVDs under visible light irradiation. The physicochemical properties of the photocatalyst were elucidated using a range of characterization techniques. Response surface modelling was used to evaluate the interactions between the independent variables: initial pH of the solution, photocatalyst loading and initial concentration of the pollutants. The results showed that there were significant interactions between initial concentration and photocatalyst loading for EFV degradation while the interactions between photocatalyst loading and initial concentration, and initial pH of the solution and photocatalyst loading were significant for NVP degradation. The highest degradation efficiencies were 84 and 100% for EFV and NVP, respectively. Scavenger tests revealed that the hydroxyl free radicals and photo-induced holes were the dominant active species that promoted the degradation of ARVDs. The synthesized photocatalyst nanocomposite demonstrated its efficacy in degradation of ARVDs in water under visible light irradiation.

Electrochemical and photocatalytic properties of ZnO nanostructures deposited on nanoporous anodized aluminum oxide membrane and its application for degradation of reactive blue 19 in textile wastewater

The current study's objective was to develop a ZnO photocatalyst for the treatment of reactive blue 19 (RB19) from textile wastewater by depositing ZnO nanostructures over nanoporous anodized aluminum oxide (ZnO-AAO). The ZnO-AAO membrane was created using the atomic layer deposition (ALD) technique. SEM, XRD, and EDS morphological and structural characterizations demonstrated that ZnO nanostructures were successfully deposited on the AAO membrane. Studying the optical properties revealed that the band gap energies for ZnO, AAO, and ZnO-AAO membranes were found to be 3.19, 2.85, and 2.92 eV, respectively. This resulted in an improvement in the separation efficiency of photo-excited electrons and holes as well as an increase in the photocatalytic activity of the ZnO-AAO sample in the visible light region. Studying the electrochemical parameters revealed that ZnO-AAO had the lowest charge transfer resistance, which indicates that photoinduced electrons and holes in ZnO-AAO contacts effectively transfer charge and have slower recombination rates. According to research on photocatalytic performance, ZnO-AAO and ZnO photocatalysts required 70 and 90 min of visible light exposure to completely decolorize RB19, respectively. The photocatalytic decolorization of RB19 in an actual sample of textile wastewater showed that the dye could be effectively removed by photocatalytic means when ZnO-AAO membrane photocatalyst was present.

Contributions of Surface Oxygen Species and Photoinduced Holes on Photothermocatalytic Toluene Oxidation over CeO2–MgO

To reveal the activity enhancement mechanism of volatile organic compounds (VOC) oxidation reaction, is vital for developing high-efficiency and cost-effective photothermocatalytic materials. Herein, porous and low-cost CeO2–MgO composite oxides were simply constructed via the solution combustion method and applied for toluene photothermocatalytic oxidation. The conversion rate for 1500 ppm of toluene over the optimized sample could reach 90% under the photothermocatalytic process at 330 °C and a gas hourly space velocity of 60,000 mL·g–1·h–1. Both gas phase oxygen and reactive oxygen species (ROS) played the dominant role in the photothermocatalytic activity while the total contribution rate of photoinduced holes and surface lattice oxygen was 25% to the activity. In situ Fourier transform infrared and electron paramagnetic resonance results revealed that the synergistic photothermo activation of molecular oxygen accelerated the low-temperature ROS formation. Under irradiation, photoinduced electrons could benefit the efficient transfer from superoxide radicals to peroxide radicals on material. Hence, it provides not only a comprehensive understanding on the activity enhancement mechanism at the molecular level but also a theoretical reference for designing objective catalysts for VOC abatement.

Ti–Si–Zr–Zn Nanometallic Glass Substrate with a Tunable Zinc Composition for Surface-Enhanced Raman Scattering of Cytochrome c

As a remarkably powerful analytical technique, surface-enhanced Raman scattering (SERS) continues to find applications from molecular biology and chemistry to environmental and food sciences. In search of reliable and affordable SERS substrates, the development has moved from noble metals to other diverse types of structures, e.g., nano-engineered semiconductor materials, but the cost of the enhancement factors (EF) substantially decreasing. In this work, we employ biocompatible thin films of Ti-Si-Zr-Zn nanometallic glasses as the SERS substrates, while tuning the Zn composition. Aided by quartz crystal microbalance, we find that the composition of 4.3% Zn (Ti-Si-Zr-Zn4.3) gives an ultrasensitive detection of Cytochrome c (Cyt c) with an EF of 1.38 × 104, 10-fold higher than the previously reported EF in the semiconducting metal oxide nanomaterials, such as TiO2, and even comparable to the reported noble-metal-assisted semiconducting tungsten oxide hydrate. Ti-Si-Zr-Zn4.3 exhibits a stronger adhesion force toward Cyt c, which ensures the strong binding of Cyt c to the surface, facilitating the Cyt c adsorption onto the surface and thus enhancing the SERS signal. The high separation efficiency of photoinduced electrons and holes in Ti-Si-Zr-Zn4.3 is also acknowledged for promoting the SERS activity.

Construction of ternary heterostructured Ag/Ag2O@ZnO@g-C3N4 nanocomposite as an widened visible light photocatalyst for the organic oxidation

Two dimension g-C3N4 was synthesized by thermal polymerization using mixture urea and melamine. The metal oxide Ag2O and ZnO were loaded to nanolayer of g-C3N4. The composites Ag/Ag2O@ZnO@g-C3N4 were constructed by Ag2O and ZnO which were defined for p-type and n-type semiconductor to form heterojunctions. The samples were characterized by X ray diffraction(XRD), transmission electron microscopy(TEM), X ray photoelectron spectroscopy (XPS) and UV/Vis diffuse reflectance spectroscopy (UV–vis DRS). The experiment results indicate that Ag2O and ZnO were uniformly loaded to nanolayer of g-C3N4 and heterojunction of Ag/Ag2O@ZnO@g-C3N4 was constructed. The photocatalytic activity of Ag/Ag2O@ZnO@g-C3N4 was characterized by degradation of methylene blue (MB) under the widened visible light-driven. The photodegradation efficiency of MB was 64.486%, 87.724%, 91.611%, 96.700% and 99.999% over g-C3N4, ZnO@g-C3N4, Ag/Ag2O@g-C3N4, Ag/Ag2O@ZnO@g-C3N4-1 and Ag/Ag2O@ZnO@g-C3N4-2, respectively. The results show that the photocatalytic activity of Ag/Ag2O@ZnO@g-C3N4 was enhanced based on the p-n structure which decreased the recombination rates of photoinduced electron hole between metal oxide and g-C3N4. Finally, photocatalytic mechanism of Ag/Ag2O@ZnO@g-C3N4 was discussed for ternary heterostructured catalysts.

A novel Ni0.85Se/MoSSe heterojunction demonstrated omnipotent boosting catalytic ability in photocatalysis, photoelectrochemistry and electrocatalysis

A new type II 0D/3D Ni0.85Se/MoSSe heterojunction photocatalyst was prepared via a hydrothermal method. These Ni0.85Se/MoSSe heterojunction photocatalysts exhibited outstanding catalytic performance in photocatalysis, electrocatalysis and photoelectrochemistry. By optimizing the composited ratio of MoSSe, the catalyst showed a photocurrent density of 32.95 μA/cm2 which was 4.23 and 32.95 times that of pure Ni0.85Se and MoSSe, respectively. In the degradation of tetracycline hydrochloride, it displayed the largest degradation rate, boosting it 2.81 and 10.3 times that of Ni0.85Se and MoSSe, respectively. In hydrogen evolution reaction and oxygen evolution reaction, the Ni0.85Se/MoSSe heterojunction photocatalyst had Tafel slope of 58 and 37 mV/dec, respectively, which were both much lower than Ni0.85Se (77 and 171 mV/dec) and MoSSe (102 and 389 mV/dec). With structure and morphology analysis, the MoSSe has a 3D reticular structure which is more suitable for loading 0D Ni0.85Se nanoparticles to construct a 0D/3D heterostructure, where carriers generated in Ni0.85Se will be easily collected by MoSSe to accelerate the carriers’ separation and transmission. Moreover, the conduction band and valance band of MoSSe are both lower than those of Ni0.85Se, forming a type-II heterojunction where photoinduced electrons and holes will be separated to different sites. Thus, oxidation and reduction reactions will occur in different locations to demonstrate outstanding catalytic performance.

Controllable synthesis of copper-organic frameworks via ligand adjustment for enhanced photo-Fenton-like catalysis

The efficient heterogeneous photo-Fenton-like catalysts based on two secondary ligand-induced Cu(II) metal–organic frameworks (Cu-MOF-1 and Cu-MOF-2) were constructed for the first time and investigated for the degradation of multiple antibiotics. Herein, two novel Cu-MOFs were prepared using mixed ligands by a facile hydrothermal method. The one-dimensional (1D) nanotube-like structure could be obtained by using V-shaped, long and rigid 4,4′-bis(3-pyridylformamide)diphenylether (3-padpe) ligand in Cu-MOF-1, while polynuclear Cu cluster could be prepared more easily by using short and small isonicotinic acid (HIA) ligand in Cu-MOF-2. Their photocatalytic performances were measured by degradation of multiple antibiotics in Fenton-like system. Comparatively, Cu-MOF-2 exhibited superior photo-Fenton-like performance under visible light irradiation. The outstanding catalytic performance of Cu-MOF-2 was ascribed to the tetranuclear Cu cluster configuration and excellent ability of photoinduced charge transfer and hole separation thus improved the photo-Fenton activity. In addition, Cu-MOF-2 showed high photo-Fenton activity in wide pH working range 3–10 and maintained wonderful stability after five cyclic experiments. The degradation intermediates and pathways were deeply studied. The main active species h+, O2− and OH worked together in photo-Fenton-like system and possible degradation mechanism was proposed. This study provided a new approach to design the Cu-based MOFs Fenton-like catalysts.

Cu doped Fe2O3 growing a nickel foam for sulfadiazine degradation in peroxymonosulfate assisting photo-electrochemical system: Performance, mechanism and degradation pathway

In this study, cost-effective and easily recovery Cu doped Fe2O3 in-situ growing on a nickel foam (Cu-Fe2O3/NF) was successfully fabricated and employed in peroxymonosulfate (PMS) assisting visible-light photoelectrochemical oxidation (VL + EC + catalyst + PMS) system for sulfadiazine (SD) removal. The optimum 2Cu-Fe2O3/NF exhibited excellent catalytic efficiency toward SD degradation in the VL + EC + catalyst + PMS system, 100% of SD being removed in 10 min and the firs-order reaction kinetic constant being 41.30 × 10-2 min−1. The excellent catalytic efficiency of 2Cu-Fe2O3/NF was due to the depressed recombination of photoinduced electron and hole, the enhanced electron transfer efficiency, more Fe2+, Cu+ and Ni2+ in sample resulting from Cu doping, and more active sites owing to the bulk thick petals-like of Fe2O3 being changed to thinner flakes after Cu doping. Therefore, a large number of reactive oxygen species including •OH, •O2− and h+ in the VL + EC + 2Cu-Fe2O3/NF + PMS system were produced to degrade SD. The mechanism of SD degradation in the system was explored in detail. The 2Cu-Fe2O3/NF displayed adaptation ability for a wide range, good anti-interference ability toward ions in real water. More inspiring, benefiting from the in-situ growth of Cu-Fe2O3 on NF surface, 2Cu-Fe2O3/NF exhibited good durability and recycle ability. This study provides a worthy reference for designing efficient and easily recycled catalysts and promotes the practical application possibility of low-cost Fe2O3 in antibiotics removal.

Bimetallic PtNi alloy modified 2D g-C3N4 nanosheets as an efficient cocatalyst for enhancing photocatalytic hydrogen evolution

Platinum-based alloy materials as effective cocatalysts in improving the performance of photocatalytic H2 production have raised great interest. Herein, a facile strategy of chemical reduction is established to synthesize bimetallic PtNi nanoparticles on 2D g-C3N4 nanosheets with excellent photocatalytic activity. The addition of PtNi nanoparticles can provide new H+ reduction sites and increase more active sites of the material. The synergistic effect between PtNi alloy nanoparticles and 2D g-C3N4 nanosheets can regulate electronic structure, narrow the band, accelerate charge transfer efficiency and inhabit the recombination of photo-induced electron (e−) and hole pairs (h+), contributing to the improvement of hydrogen evolution activity. The optimal hydrogen evolution rate of Pt0.6Ni0.4/CN shows higher hydrogen evolution rate (9528 μmol·g−1·h−1), which is 13.1 times than that of pure g-C3N4 nanosheets. Besides, a possible mechanism of photocatalytic hydrogen generation has been brought up according to a series of physical and chemical characterization. This work also provides a potential idea of developing cocatalysts integrating metal alloys with 2D g-C3N4 nanosheets for promoting photocatalytic hydrogen evolution.

Light-driven ammonium oxidation to dinitrogen gas by self-photosensitized biohybrid anammox systems

The anaerobic ammonium oxidation (anammox) process exerts a very vital role in the global nitrogen cycle (estimated to contribute 30%-50% N2 production in the oceans) and presents superiority in water/wastewater nitrogen removal performance. Until now, anammox bacteria can convert ammonium (NH4+) to dinitrogen gas (N2) with nitrite (NO2-), nitric oxide (NO), and even electrode (anode) as electron acceptors. However, it is still unclear whether anammox bacteria could utilize photoexcited holes as electron acceptors to directly oxide NH4+ to N2. Here, we constructed an anammox-cadmium sulfide nanoparticles (CdS NPs) biohybrid system. The photoinduced holes from the CdS NPs could be utilized by anammox bacteria to oxidize NH4+ to N2. 15N-isotope labeling experiments demonstrated that NH2OH instead of NO was the real intermediate. Metatranscriptomics data further proved a similar pathway for NH4+ conversion with anodes as electron acceptors. This study provides a promising and energy-efficient alternative for nitrogen removal from water/wastewater.

Persulfate promoted visible photocatalytic elimination of bisphenol A by g-C3N4–CeO2 S-scheme heterojunction: The dominant role of photo-induced holes

In the last few years, coupling heterogeneous photocatalysis with persulfate (PDS) activation process is an efficient approach to generate abundant reactive oxidative species towards organic contaminant removal in water, however, the key role of PDS in photocatalytic process remains ambiguous. Herein, a novel g-C3N4–CeO2 (CN–CeO2) step-scheme (S-scheme) composite was constructed to photo-degrade bisphenol A (BPA) with the presence of PDS under visible irradiation. At 2.0 mM PDS, 0.7 g/L CN–CeO2 and natural pH 6.2, 94.2% of BPA could be eliminated in 60 min under visible light (Vis) illumination. Aside from the previous view of free radical generation, it tends to assume that most of PDS molecules acted as electron sacrificial agents for capturing photo-induced e− to form sulfate ions, greatly improving the charge carrier separation and thus enhancing the oxidation capacity of nonradical hole (h+) for the removal of BPA. Good correlations are further found between the rate constant and descriptor variables (i.e., Hammett constant σ−/σ+ and half-wave potential E1/2), exhibiting selective oxidation for organic pollutants in the Vis/CN–CeO2/PDS system. The study brings more insights into mechanistic understanding of persulfate-enhanced photocatalytic process for addressing water decontamination.

Perovskite LaMnO3 Composite Graphene Carbon Nitride g-C3N4 Improves the Photocatalytic Performance of Tetracycline Degradation

With the extensive use and improper treatment of antibiotics, antibiotic pollution in aquaculture wastewater has become increasingly severe. Tetracycline antibiotics have become one of the most commonly used fishery antibiotics. In this study, a Z-scheme heterostructure LaMnO3/g-C3N4 was constructed by the sol–gel method as a photocatalyst to degrade tetracycline, and the influence of anions on the degradation effect was investigated. The LaMnO3/g-C3N4 hybrid was successfully constructed by scanning electron microscope, Fourier transform infrared spectrum, and X-ray diffraction. The results of degradation experiments demonstrated that the maximum tetracycline degradation efficiency of LaMnO3/g-C3N4-10 (LMO/CN-10) was 80%, the removal rate of TC decreased from 71% to 48% when the concentration of chloride ions increased from 0 mM to 10 mM, and the removal rate of TC decreased from 75% to 28% when the concentration of carbonate ions increased from 0 mM to 10 mM. This enhanced photocatalytic activity was attributed to the formation of a Z-scheme structure that promoted the separation of photoinduced electron holes while maintaining its own strong redox ability. Finally, the photocatalytic mechanism was designed based on the free radical trapping experiment, electrochemical impedance, and photoluminescence spectra, providing an opportunity for the construction of a new photocatalyst for the treatment of aquaculture tailwater in the future.

Visible-light-induced strong oxidation capacity of metal-free carbon nanodots through photo-induced surface reduction for photocatalytic antibacterial and tumor therapy

Biocompatible metal-free carbon dots (CDs) with good photo-induced strong oxidation capacity in aqueous solutions are scarce for high-performance photocatalytic antibacterial and tumor therapy. In this work, we achieved effective visible light-induced cell death and antibacterial performance based on biocompatible metal-free CDs. The visible-light-induced reducing ability of the surface electron-withdrawing structure of the CDs allowed for the remaining photo-induced holes with high oxidation capacity to oxidize water molecules and generate hydroxyl radicals. Antibiotic-resistant bacteria were effectively inhibited by the CDs under xenon lamp irradiation with 450 nm long pass filter. Moreover, CD-based tumor photocatalytic therapy in mice was achieved using a xenon lamp with 450 nm long pass filter (0.3 W cm−2).

Charge Transfer in Amine-Free CsPbBr3 Perovskite Nanocrystals and Organic Hole-Acceptor Hybrid Structures

Outstanding optoelectronic properties of cesium lead bromide (CsPbBr3) perovskite nanocrystals (PNCs) are recognized in various photonic devices. The surface chemistry of PNCs determines the excited states of PNCs, and their interactions with charge drive redox-active molecules. Here, we have investigated the potential difference between the surface modification of different CsPbBr3-based PNCs (amine-free and amine-based) with the hole-accepting organic molecule, i.e., 7,7-diethyl-5,7-dihydroindeno[2,1-b] carbazole (SPS-IND-Cbz). We have evaluated photoinduced hole transfer (PHT) with the steady-state photoluminescence and lifetime decay curves. Excitingly, the resulting PHT in amine-free CsPbBr3 PNC was nearly twice that of the amine-based CsPbBr3 PNC. Further, we have studied the photocurrent density of amine-free CsPbBr3 PNCs in the newly introduced organic molecule (SPS-IND-Cbz), enhancing the photocurrent responsivity, which could open a promising perspective for implementing these fascinating materials in various photonic strategies.