Achieving high-efficient photocatalytic persulfate-activated degradation of tetracycline via carbon dots modified MIL-101(Fe)octahedrons

The synergistic reaction of photocatalysis and advanced oxidation is a valid strategy for the degradation of harmful antibiotic wastewater.Herein,carbon dots(CDs)modified MIL-101(Fe)octahedrons to form CDs/MIL-101(Fe)composite photocatalyst was synthesized for visible light-driven photocatalytic/persulfate(PS)-activated tetracycline(TC)degradation.The electron spin resonance(ESR)spectra,scavenging experiment and electrochemical analysis were carried out to reveal that the high visible light-driven photocatalytic degradation activity of TC over CDs/MIL-101(Fe)photocatalysts is not only ascribed to the production of free active radicals in the CDs/MIL-101(Fe)/PS system(·OH,·SO_(4-),^(1)O_(2),h^(+)and·O_(2)^(-))but also attributed to the consumption of electrons caused by the PS,which can suppress the recombination of photo-generated carriers as well as strong light scattering and electron trapping effects of CDs.Finally,the possible degradation pathways were proposed by analyzing intermediates via liquid chromatography-mass spectrometry technique.This research presents a rational design conception to construct a CDs/PS-based photocatalysis/advanced oxidation technology with high-efficient degradation activity for the remediation of organic antibiotic pollutant wastewater and for the improvement of carrier transport kinetics of photocatalysts.

Nanodiamonds decorated yolk-shell ZnFe_(2)O_(4) sphere as magnetically separable and recyclable composite for boosting antibiotic degradation performance

Photocatalysis is an environmentally friendly and energy-saving technology, which can effectively remove persistent dangerous pollutants in the water. Pitifully, optical absorption capacity and carrier separation have become major bottlenecks for marvelous photocatalytic performance of photocatalysts.Herein, to address these issue, Nanodiamonds/yolk-shell ZnFe_(2)O_(4) spheres(NDs/ZFO) nanocomposites were successfully constructed via a facile two-step of solvothermal and calcination methods. The synthesized optimal NDs/ZFO-10 nanocomposite exhibits superior photocatalytic degradation activity of antibiotic under visible light, approximately 85% of the total tetracycline(TC) is degraded, and this photocatalyst shows durable cycling stability. This stems from two aspects of refinement: improvement of light absorption capacity and photo-induced charges migration and separation. In addition, the NDs/ZFO composite photocatalyst features excellent magnetic recovery capability, facilitating the recovery of photocatalyst in industry. This study opens a new chapter in the combination of NDs with magnetic materials, and deepens the understanding of the application of NDs modified composite photocatalysts.

Pomelo biochar as an electron acceptor to modify graphitic carbon nitride for boosting visible-light-driven photocatalytic degradation of tetracycline

In this study,biochar(BC)derived from pomelo was prepared via a high-temperature calcination method to modify the graphitic carbon nitride(g-C_(3)N_(4))to synthesize the BC/g-C_(3)N_(4)composite for the degradation of the tetracycline(TC)antibiotic under visible light irradiation.The experimental results exhibit that the optimal feeding weight ratio of biochar/urea is 0.03:1 in BC/g-C_(3)N_(4)composite could show the best photocatalytic activity with the degradation rate of tetracycline is 83%in 100 min irradiation.The improvement of photocatalytic activity is mainly attributed to the following two points:(i)the strong bonding with π-π stacking between BC and g-C_(3)N_(4)make the photogenerated electrons of light-excited g-C_(3)N_(4)transfer to BC,quickly and improve the separation efficiency of carriers;(ii)the introduction of BC reduces the distance for photogenerated electrons to migrate to the surface and increases the specific surface area for providing more active sites.This study provides a sustainable,economical and promising method for the synthesis of photocatalytic materials their application to wastewater treatment.

Ternary Ni_(2)P/Bi_(2)MoO_(6)/g-C_(3)N_(4)composite with Z-scheme electron transfer path for enhanced removal broad-spectrum antibiotics by the synergistic effect of adsorption and photocatalysis

Constructing the stable,low-cost,efficient,and highly adaptable visible light-driven photocatalyst to implement the synergistic effect of photocatalysis and adsorption has been excavated a promising strategy to deal with antibiotic pollution in water bodies.Herein,a novel 3 D ternary Z-scheme heterojunction photocatalyst Ni_(2)P/Bi_(2)MoO_(6)/g-C_(3)N_(4)(Ni_(2)P/BMO/CN)was fabricated by a simple solvothermal method in which the broad spectrum antibiotics(mainly tetracyclines and supplemented by quinolones)were used as target pollution sources to evaluate its adsorption and photocatalytic performance.Notably,the Zscheme composite significantly exhibit the enhancement for degradation efficiency of tetracycline and other antibiotic by using Ni_(2)P nanoparticles as electron conductor.Active species capture experiment and electron spin resonance(ESR)technology reveal the mechanism of Z-scheme Ni_(2)P/BMO/CN photocatalytic reaction in detail.In addition,based on the identification of intermediates by liquid chromatography–mass spectroscopy(LC–MS),the possible photocatalytic degradation pathways of TC were proposed.

CdS nanoparticles decorated hexagonal Fe_(2)O_(3) nanosheets with a Z-scheme photogenerated electron transfer path for improved visible-light photocatalytic hydrogen production

Photocatalytic water splitting for hydrogen production(H_(2))is one of the main potential applications of photocatalytic technology,which can use solar energy as the energy required for chemical reactions to alleviate the energy crisis.In this work,zero-dimensional/two-dimensional(0D/2D)contact surface CdS/α-Fe_(2)O_(3)(CF)heterojunction photocatalyst was synthesized via a simple solvothermal method.Photocatalytic hydrogen production experiments revealed that the CF-15 sample shows the optimal photocatalytic H_(2)rate(1806μmol·h^(-1)·g^(-1))and apparent quantum efficiency(AQE=13.7%atλ=420 nm).The enhancement of photocatalytic performance is mainly attributed to the contact of 0D/2D interface and the synergistic effect of Z-scheme electron transfer mechanism.This work provides an effective way for modified composite semiconductor photocatalyst by constructing special interface heterojunction to achieve highly efficiently catalysis.

Improvement of synergistic effect photocatalytic/peroxymonosulfate activation for degradation of amoxicillin using carbon dots anchored on rod-like CoFe_(2)O_(4)

β-lactam antibiotics in aquatic environment have severely damaged ecological stability and caused a series of environmental pollution problems to be solved urgently.Herein,a novel composite photocatalyst prepared by loading carbon dots(CDs)onto rod-like CoFe_(2)O_(4)(CFO),which can effectively degrade amoxicillin(AMX)by photocata lytic/peroxy mono sulfate(PMS)activation under visible light irradiation.The degradation results exhibits that the optimal degradation efficiency with 97.5%within 80 min is achievd by the CDs-CFO-5 composite.Such enhanced activity is ascribed to the introduction of CDs that effectively improves the separation efficiency of photogenerated electron pairs and creates new active sites as electron bridges that improve the photocata lytic performance.More importantly,a strong synergistic between CDs and photo-induced electrons generated from CFO can further activiate PMS to provide more SO4-·and·OH radicals for boosting the degradation ability towards AMX.The present study aims to elucidate positive role of CDs in photocata lytic/peroxy monosulfate activation during the degradation reaction.

Highly efficient visible/near-infrared light photocatalytic degradation of antibiotic wastewater over 3D yolk-shell ZnFe_(2)O_(4)supported 0D carbon dots with up-conversion property

The development of effective visible and near-infrared photocatalysts is highly promising in the current field of photocatalysis.Herein,carbon dots/ZnFe_(2)O_(4)(CDs/ZFO)with coating zero dimensional(0D)CDs on the surface of three dimensional(3D)yolk-shell ZFO spheres was designed and synthesized via a selftemplated solvothermal method.The as-prepared CDs/ZFO composites displayed outstanding visible and near-infrared photocatalytic degradation activity of tetracycline(TC),and the optimal 3%CDs/ZFO sample with loading 3%(mass)CDs displayed the highest photocatalytic TC degradation ability under visible light(79.5%within 120 min)and near-infrared light(41%within 120 min).The enhancement of photocatalytic activity for CDs/ZFO composite is mainly ascribed to the fact that 0D/3D yolk-shell CDs/ZFO structure not only effectively reflect the incident light to increase the utilization efficiency of solar light,but also utilize the up-conversion photoluminescence and electronic conductivity properties of CDs to broaden sunlight absorption range and promote separation and transfer of electron-hole pairs.

Controllably grown single-crystal films as flexoelectric nanogenerators for continuous direct current output

Until now,conventional nanogenerators could only produce electric pulses with relatively low-power densities.Herein,we invent a novel controllable growth technique for two-dimensional(2-D)cuprous oxide(p-Cu2O)single-crystal films,and on this basis,a new concept of 2-D single-crystal film flexoelectric nanogenerators(FENGs)are rationally designed and constructed for the first time,which has the characteristics of long-range order lattice,few grain boundaries and defects.More importantly,the accumulated built-in polarization potential in the bent 2-D p-Cu2O single-crystal film FENGs is in the same orientation as the output electricity,resulting in the first nanogenerator that can output continuous and stable electric signals with high voltage(Voc of 2.8 V),current(Jsc of 11.5μA·cm^(-2))and power density(14.4μW·cm^(-2)),exhibiting great practical application potential for power generation and motion capture.This research breaks new ground and establishes a precedent for high-performance and continuous-output nanogenerators,as well as smart wearable sensors.

Synergistic CO_(2)reduction and tetracycline degradation by CuInZnS-Ti_(3)C_(2)T_(x)in one photoredox cycle

Optimizing photocatalytic CO_(2)reduction with simultaneous pollutant degradation is highly desired.However,the photocatalytic efficiency is restricted by the unmatched redox ability,high carriers’recombination rate,and lack of reactive sites of the present photocatalysts.Herein,the CuInZnS-Ti_(3)C_(2)T_(x)hybrid with matched redox ability and suitable CO_(2)adsorption property was rationally synthesized.The nucleation and growth process of CuInZnS was interfered by the addition of Ti_(3)C_(2)T_(x)with a negative charge,resulting in thinner nanosheets and richer reactive sites.Besides,the Schottky heterojunction built in the hybrid simultaneously improved the photoexcited charge transfer property,sunlight absorption range,and CO_(2)adsorption ability.Consequently,upon exposure to sunlight,CuInZnS-Ti_(3)C_(2)T_(x)exhibited an efficient photocatalytic CO_(2)reduction performance(10.2μmol·h^(−1)·g^(−1))with synergetic tetracycline degradation,obviously higher than that of pure CuInZnS.Based on the combination of theoretical calculation and experimental characterization,the photocatalytic mechanism was investigated comprehensively.This work offers a reference for the remission of worldwide energy shortage and environmental pollution problems.