Fabrication Of Z-scheme Research Articles

Fabrication of Z-scheme Fe2O3/g-C3N4 nanocomposite with improved visible light induced photodegradation of pharmaceutical pollutants and photoelectrochemical water oxidation

The photodegradation and photoelectrochemical performance of Fe2O3 catalyst is an encouraging visible-light induced catalyst owing to its less harmfulness, cheap and ecofriendly. However, owing to its quick charge carriers recombination rate and less lifespan of charge carriers obstructs its catalyst application. Therefore, it has been lately established that the construction of heterojunction with other semiconductor might be a possible method to improve its catalytic activity. Herein, a novel Z-scheme Fe2O3/g-C3N4 heterostructure catalyst has been synthesized by a simple hydrothermal technique and studied its photoelectrochemical and photodegradation activity. The addition of g-C3N4 greatly improves the light absorption ability light, reduced charge recombination rate and progress the charge transportation. The composite catalyst exhibited the superior photodegradation performance (97.8 %) of sulfamethoxazole antibiotic remedy within 30 min of visible light illumination. •OH and •O2– radicals show a key role for dye degradation activity, and proposed a possible photodegradation charge carrier transfer mechanism based on a potential band structures of composite catalyst. Furthermore, the prepared catalysts are further used to examine the photoelectrochemical properties for hydrogen generation. The Fe2O3/g-C3N4 nanocomposite photoelectrode exhibited enriched photocurrent density (0.764 mA/cm2) than g-C3N4 (0.271 mA/cm2) and Fe2O3 (0.370 mA/cm2) photoelectrodes, which ∼ 2.8 and ∼2.1 folds greater photocurrent density than pure photoelectrodes. Electrochemical impedance spectroscopy analysis revealed that the composite electrode has minimal charge transfer resistance and greater electron transfer ability. Therefore, the current study presents a facile formation of Z-scheme catalyst and offers a sustainable method to eradicate water impurities and hydrogen generation by renewable solar energy.

Fabrication of Z-Scheme CeVO4/BiVO4 Heterojunction and Its Enhanced Photocatalytic Degradation of NFX

Fabrication of Z-Scheme CeVO4/BiVO4 Heterojunction and Its Enhanced Photocatalytic Degradation of NFX

Fabrication of Z-scheme ZnIn2S4/ZnSe heterostructed microspheres toward antibiotic degradation from real pharmaceutical wastewater

BackgroundAlthough Z-type heterojunction can significantly improve the catalytic performance of photocatalyst, there have been few reports on Z-type heterojunction about ZnSe. Therefore, it is meaningful to search for the Z-type photocatalyst in ZnSe to enhance its photocatalytic efficiency. MotivationZnIn2S4, as a novel photocatalyst, its VB (1.72V) and CB (−0.71V) can match with ZnSe, indicating the potential formation of a Z-type heterojunction. Therefore, we hope to construct the ZnIn2S4/ZnSe photocatalyst by forming Z-type heterojunction to boost the photocatalytic activity of ZnSe. MethodsIn this paper, ZnIn2S4/ZnSe heterojunction was prepared through hydrothermal method using ZnIn2S4, Zn(CH3COO)2·2H2O and Na2SeO3 as raw materials, and heated at 180 °C for 24 h. Results and conclusionsThe optimum 30 % ZnIn2S4/ZnSe nanocomposites exhibit superior photocatalytic degradation towards Tc and OTC, with removal rates reaching 80 % and 74 % within 60 min, respectively, significantly higher than the degradation efficiency of pure ZnSe. And in the process of photodegradation for antibiotics, the most significant contribution rate are ∙O2− and h+, while ·OH plays a minor role. Herein, we have provided a good example for removing antibiotic residues by using ZnSe based Z-type heterojunction towards environmental remediation.

Fabrication of Z-scheme ZnO/g-C3N4/ZnS nanocomposites using high power laser for methylene blue degradation

Photocatalysis plays a vital role in addressing environmental challenges by harnessing solar energy for efficient pollutant degradation. In this study, we investigate the photocatalytic activity of a ZnO/g-C3N4/ZnS composite system in the degradation of methylene blue, a widely used dye with detrimental effects on aquatic ecosystems. The composite materials were synthesized using a facile and scalable approach, and their structural properties, morphologies, sizes, and elemental compositions were characterized using different analytical techniques. The ZnO/g-C3N4/ZnS composite exhibited enhanced photocatalytic performance compared to individual components. Remarkably, the degradation efficiency reached 80% for the composite with a 30% ZnO composition, surpassing the efficiencies of ZnS alone (29%) and ZnS/g-C3N4 (65%). The composite’s higher degradation efficiency is due to synergistic semiconductor effects, enhancing charge transfer and reducing electron–hole recombination. ZnO incorporation increases active sites and surface area, improving interaction with methylene blue. The favorable band edge positions of ZnO aligned with ZnS and g-C3N4, facilitating the utilization of a broader spectrum of solar light. The composite’s photocatalytic activity was achieved under UV light irradiation, demonstrating its potential for sustainable and energy-efficient applications. This study highlights the significance of composite design and the Z-scheme concept in photocatalysis, offering insights into the development of advanced materials for environmental remediation. The findings contribute to the understanding of efficient solar-driven pollutant degradation and pave the way for the design and optimization of innovative photocatalytic systems for sustainable environmental solutions.

Fabrication of Z-scheme ZnO/g-C3N4 heterojunction modified by silver nanoparticles for photocatalytic removal of Norfloxacin and Rhodamine B

A novel ternary photocatalyst with a Z-scheme heterojunction was successfully synthesized through the deposition of Ag nanoparticles onto the surface of a ZnO/g-C3N4 composite. The prepared photocatalysts were characterized by XRD, FT-IR, XPS, HRSEM, TEM, DRS, PL, EIS, TPC, and M-S. The photocatalytic performance of the as-synthesized photocatalysts was systematically investigated through the photodegradation of norfloxacin (NOR) and rhodamine B (RhB) under visible light irradiation. The photodegradation efficiency of 5% Ag/ZnO/g-C3N4 (5AZCN) composite photocatalyst reached 86.7% (480 min) and 98.0% (60 min) for NOR and RhB, respectively. Moreover, the apparent rate constants of the 5AZCN composite photocatalysts for NOR and RhB were found to be 3.4 and 22.2 times higher than that of the ZCN composite photocatalysts, respectively. The significantly enhanced photocatalytic performance was ascribed to the widened range of visible light response and the efficient separation and migration of carriers facilitated by the introduction of Ag nanoparticles that functioned as electron transfer mediators. Based on the free radicals quenching experiment and electron spin resonance (ESR) spectroscopy characterization, superoxide radicals (·O2−) were the main reactive species in the photodegradation process. Furthermore, the charge transfer process was proved to be a Z-scheme transfer mechanism. This work provides a promising approach to simply constructing novel efficient Z-scheme photocatalysts for the elimination of environmental pollutants.

Fabrication of Z-scheme Bi7O9I3/g-C3N4 heterojunction modified by carbon quantum dots for synchronous photocatalytic removal of Cr (Ⅵ) and organic pollutants

Chromium(VI) (Cr(VI)), a highly toxic metal ion, generally co-exists with organic pollutants in industrial effluents. The clean and effective technology for water purification is an imperative issue but still a challenging task. A series of Bi7O9I3/g-C3N4 (BOI/CN) composites modified by lignin-derived carbon quantum dots (CQDs) were fabricated by hydrothermal method and applied for synchronous photocatalytic removal of Cr (Ⅵ) and levofloxacin (LEV). With the modification of CQDs in BOI/CN heterojunction, the 0.5-CQD/BOI/CN photocatalyst (0.5% content of CQDs) exhibited stronger light-harvesting capacity, more efficient charge separation, and faster electron transfer. Compared to those of BOI (51.2%), CN (36.8%), and BOI/CN (74.4%), the photoreduction efficiency of Cr(VI) reached up to 100% by 0.5-CQD/BOI/CN under 60 min of light irradiation, together with 94.8% degradation efficiency of LEV. The degradation of LEV was dominantly controlled by active species (•OH and •O2−) identified by electron paramagnetic resonance analysis and free radical trapping experiments. The intermediates of LEV were determined by LC-MS and the possible degradation pathway was speculated in combination with density functional theory calculation, involving defluorination, decarboxylation, quinolone rings opening, and piperazine moieties oxidation reactions. This work provides an advanced strategy for the fabrication of high-efficiency CQDs-based Z-scheme photocatalysts for environmental remediation.

Fabrication of Z-scheme CdS/H5PMo10V2O40/g-C3N4 for the photocatalytic depolymerization of lignin into aromatic monomers

As the most abundant resource composed of aromatic groups in nature, lignin harbors significant potential for the production of bio-based fuels and chemicals. In recent years, solar-driven photocatalysis with its mild, low cost and environmental benign, has been employed for lignin depolymerization. Herein, we designed a Z-scheme CdS/H5PMo10V2O40/g-C3N4 (CdS/HPA-2/CN) photocatalyst via hydrothermal method for the photocatalytic depolymerization of lignin. The prepared CdS/HPA-2/CN presents a nanoflower-like morphology with the average diameter of ∼600 nm. With the presence of electron-mediated HPA-2, CdS/HPA-2/CN exhibits the enhanced separation and transfer capacity of photogenerated charge carriers through Z-scheme mechanism. Result shows that the total yield (Y) of vanillin and vanillic acid from lignin depolymerization over optimized CdS/HPA-2/CN can reach to 32.7 mg/g lignin in DMF/formic acid (v/v = 40/10) for 4 h. Reusability experiment of optimized CdS/HPA-2/CN displays that Y (26.5 mg/g lignin) can still reach to 81.0% of initial one after three cycles. Qualitative analysis of depolymerized products reveals that most components are aromatic compounds with the dominant products of vanillin and vanillic acid. Evidence also shows that photocatalysis promotes the reaction and small molecular products increased significantly after depolymerization. In addition, mechanism experiments and electron spin resonance tests exhibit that h+, ·O2− and ·OH took part in lignin depolymerization together and the effect sequence was ·O2− > ·OH > h+. In this work, as an electron mediator, HPA-2 provides the inspiration for construction of Z-scheme heterojunction, and CdS/HPA-2/CN exhibits enormous potential in lignin depolymerization by photocatalysis.

Fabrication of Z-scheme TiO2/BP/g-C3N4 nanocomposite via pulsed laser ablation in liquid for photocatalytic overall water splitting

Indirect Z-scheme heterostructure photocatalysts possess great potential for simulated light-induced overall water splitting. However, the fabrication of highly-efficient indirect Z-scheme heterostructures under solar light irradiation remains a great challenge. In this work, a novel ternary nanocomposite material comprising of TiO2 nanowires, g-C3N4 nanosheets, and black phosphorous (BP) has been fabricated successfully using pulsed laser ablation technique. A series of characterization techniques were exploited to elucidate the optical, structural, and morphological attributes of the synthesized nanostructure. Under simulated light irradiation, the fabricated TiO2/BP/g-C3N4 nanocomposite displayed stable and efficient photocatalytic overall water splitting performance with hydrogen and oxygen evolution rate of 118.2 and 240 μmol g−1h−1, respectively. The nanocomposite showed an Apparent Quantum Yield (AQY) of 7.8% (400 nm), excellent photocatalytic activity i.e. (≈5.4 times higher than TiO2/BP nanocomposite), and stability. The significant enhancement in the photocatalytic efficiency of the fabricated nanocomposite is attributed to the collective gains arising from the low bandgap, large surface area, and formation of Z-scheme that facilitated charge separation on the TiO2/BP/g-C3N4 nanocomposite.

Construction of Z-scheme Cs3PMo12O40/g-C3N4 composite photocatalyst with highly efficient photocatalytic performance under visible light irradiation

Exploitation of effective, persistent and visible-light-responsive photocatalysts is of significance for photodegrading antibiotics and organic dyes in environmental modification. Here, a novel Cs3PMo12O40/g-C3N4 (abbreviated as x% CPM/CN; x ​= ​2, 4, 6 and 8, respectively) composite was fabricated through a convenient dissolution-precipitation method. As-obtained CPM/CN composite was composed of three-dimensional (3D) CPM nanospheres and two-dimensional (2D) CN nanosheets, which was verified through SEM and TEM techniques. The interfacial interaction between CPM and CN was confirmed with XPS results, which manifested the heterojunction formation in CPM/CN composite. The prepared materials displayed excellent and durable catalytic activity for tetracycline hydrochloride (TCH), ciprofloxacin (CIP) and Rhodamine B (RhB) removal with visible light illumination (λ ​> ​420 ​nm). Particularly, 4% CPM/CN sample displayed the optimal activity, whose photodegradation rates for TCH, CIP and RhB could reach 83.11% (k ​= ​0.01255 min−1), 65.43% (k ​= ​0.00591 min−1) and 100% (k ​= ​0.64822 min−1), respectively. The improvement of photocatalytic performance was due to the enhancement in the visible light absorption and the accelerated separation and migration rate of electrons-holes. The electron spin resonance (ESR) and free radicals trapping experiments proved that superoxide radical (·O2−) and holes (h+) were dominating active species in contaminants removal. Moreover, the photocatalytic degradation pathways of TCH were detected by high performance liquid chromatography-mass spectrometry (HPLC-MS). Combined the analysis of the energy band structure and precious metal deposition test, a Z-scheme catalytic mechanism was presented in detail. This work affords novel horizons for the rational design and fabrication of Z-scheme POMs/CN-based catalysts with excellent catalytic activity for environmental protection.

Fabrication of Z-Scheme TiO2/SnS2/MoS2 ternary heterojunction arrays for enhanced photocatalytic and photoelectrochemical performance under visible light

In the current work, Z-scheme TiO2/SnS2/MoS2 ternary heterojunction arrays were synthesised on a fluorine-doped tin oxide conductive glass by using a facile hydrothermal technique. The microstructures, energy band structures, and photocatalytic performances of TiO2, TiO2/SnS2, and TiO2/MoS2 were investigated. The results revealed that for methylene blue, ternary TiO2/SnS2/MoS2 exhibited considerably enhanced photocatalytic efficiency (∼79%) and the optimal transient current density (∼0.92 ​mA/cm2) under visible-light irradiation; these two values were four and eight times higher than those exhibited by TiO2, respectively. The highly improved photocatalytic and photoelectrochemical performance could be attributed to the unique microstructure and band alignment of TiO2/SnS2/MoS2. These attributes can be explained as follows: (i) the large specific surface area offers numerous active sites, (ii) the modulation of the narrow-band SnS2 and MoS2 broadens visible-light response, and (iii) the Z-scheme heterojunction effectively restricts the bulk recombination and spatially separates the photogenerated electron–hole (e−–h+) pairs.

Fabrication of Z-scheme ZnO/Bi2O4 heterojunction photocatalyst with superior photocatalytic nitrogen fixation under visible light irradiation

ZnO/Bi2O4 heterojunctions with different ratios were successfully synthesized by one-step hydrothermal method. The photocatalytic activity for nitrogen fixation was investigated by Nessler's reagent spectrophotometry and ion chromatography method for comparison. As a result, the NH4+ concentration over 10%ZnO/Bi2O4 catalyst measured by ion chromatography is 0.22 mmol L−1 h−1·gcat−1 after 150 min visible light irradiation, which is about 1/135 of that obtained by Nessler's reagent method. Furthermore, the photocatalytic activity for degradation of methyl orange and ciprofloxacin was also evaluated. 10%ZnO/Bi2O4 shows optimal photocatalytic degradation efficiency (97.5 % and 95.6 % for methyl orange and ciprofloxacin), which are 40.7 and 28.3 times that of pure ZnO. Various characterization techniques and photoelectrochemical tests have proved that such enhanced photocatalytic activity was due to the heterojunction formation between ZnO and Bi2O4, which possesses a lower charge transfer resistance and efficient electron-hole pairs separation.

Fabrication of Z-scheme Bi2WO6/CNT/TiO2 heterostructure with enhanced cephalexin photodegradation: Optimization and reaction mechanism

A Z-scheme Bi2WO6/CNT/TiO2 heterostructure was synthesized through the hydrothermal method. The photocatalysts were characterized by XRD, FTIR, SEM, EDX, TEM, UV–vis DRS, PL, and BET-BJH analyses. The photocatalytic activity of Bi2WO6/CNT/TiO2 was evaluated by the degradation of cephalexin under simulated sunlight illumination. The ternary Bi2WO6/CNT/TiO2 Z-scheme containing the optimal loading amount of 35 wt% TiO2 and 0.75 wt% CNTs, showed the best photocatalytic activity compared with pristine Bi2WO6, Bi2WO6/TiO2 and Bi2WO6/CNT/TiO2 with different mass percentage ratios. The enhanced photocatalytic activity of Bi2WO6/CNT/TiO2 was attributed to the higher specific surface area, higher visible-light adsorption spectrum, lower band gap, lower recombination of electron-hole pairs, better charge separation and higher redox ability, due to the Z-scheme construction. The optimum values of operating parameters were determined as: catalyst dose = 0.75 g/L, pH = 5, illumination time = 70 min, and cephalexin initial concentration = 20 mg/L using the central composite design. The maximum cephalexin removal efficiency in the presence of Bi2WO6/CNT/TiO2 reached 89.7% at optimum conditions. The maximum total organic carbon (TOC) removal rate was 78.9%. The photocatalytic degradation of cephalexin followed the first-order kinetic and the reaction rate by ternary composite was about 3.33 and 1.5 times, greater than those of Bi2WO6 and Bi2WO6/TiO2, respectively. The synthesized Z-scheme demonstrated an excellent chemical stability and reusability after five cyclic utilizations. According to matched Fermi level of CNTs between Bi2WO6 and TiO2, CNTs acted as electron mediator for charge transfer in the Z-scheme. Assigned to the trapping experiments, OḢ, O2−•, h+ and e- effectively improved the photodegradation process.

Fabrication of Z-scheme CuPd/SrTiO3–CuPd–Bi2O3 photocatalyst for converting organic dye containing N and S elements into (NH4)2SO4

Several novel Z-scheme CuPd/SrTiO 3 –CuPd–Bi 2 O 3 photocatalysts are prepared via chemical reduction and calcination methods to degrade organic dyes containing N and S and convert NO 2 - , NO 3 - and SO 3 2- into (NH 4 ) 2 SO 4 . Sodium borohydride (NaBH 4 ), ascorbic acid (C 6 H 8 O 6 ) and hydrazine hydrate (N 2 H 4 ·H 2 O) are selected as reductants to deposit CuPd alloy nanoparticles on corresponding photocatalyst. The influence of solar light irradiation time on photocatalytic degradation of organic dye and conversion of the generated inorganic ions is studied. The reusability and stability of the prepared photocatalysts are assessed. The results indicate that the Z-scheme CuPd/SrTiO 3 –CuPd–Bi 2 O 3 photocatalyst prepared by using NaBH 4 has best photocatalytic activity, reusability and stability. The capture experiment of active species proves that holes play crucial roles in photocatalytic degradation of organic dyes and conversion of SO 3 2- and electrons are momentous for the conversions of NO 2 - and NO 3 - . A possible mechanism on photocatalytic degradation of organic dyes containing N and S and conversions of NO 2 - , NO 3 - and SO 3 2- into (NH 4 ) 2 SO 4 caused by Z-scheme CuPd/SrTiO 3 –CuPd–Bi 2 O 3 photocatalyst is proposed. • Several novel photocatalysts are prepared via chemical reduction and calcination. • CuPd alloy cocatalyst is introduced to Z-scheme SrTiO 3 /Bi 2 O 3 photocatalytic system. • Effect of CuPd alloy gained via three reductants on catalyst activity is clarified. • Formation of alloy can boost synergistic effect of Cu and Pd in reduction reaction. • The catalyst can selectively convert organic dye containing N and S into (NH 4 ) 2 SO 4 .

Fabrication of Z-scheme Bi5O7I/MIL-53(Fe) hybrid with improved photocatalytic performance under visible light irradiation

A series of Bi5O7I/MIL-53(Fe) (BOI/MIL-w) composites were successfully prepared by a facile in-situ solvothermal approach. The matched energy bands enabled Bi5O7I and MIL-53(Fe) to form a Z-scheme heterojunction which resulted in an efficient separation of the photo-induced electron–hole pairs. The photocatalytic activity of BOI/MIL-w was evaluated by the degradation of Rhodamine B (RhB) in water under the visible light irradiation. Compared with Bi5O7I, photocatalytic performances of BOI/MIL-w notably boosted. When the content of added MIL-53(Fe) was 3 wt%, BOI/MIL-3 presented the highest activity with a degradation efficiency of 99.7% only after 60 min of irradiation. The reaction rate constant k could reach 0.0992 min−1 which was nearly 12.6 times as high as that of Bi5O7I. Moreover, BOI/MIL-w had a good stability and reusability, which could ensure its practical application. Trapping experiments confirmed that h+ and ·O2− were the dominant active species during the photocatalytic process, and further demonstrated the formation of the Z-scheme heterojunction facilitated the photocatalytic performance of BOI/MIL-w.

A novel Z-scheme porous g-C3N4 nanosheet/Ag3PO4 photocatalyst decorated with N-doped CDs for high efficiency removal of antibiotics.

A number of porous g-C3N4 nanosheet/Ag3PO4/NCDs (PCNNS/AP/NCDs) with little amounts of Ag3PO4 were synthesized via an in situ sedimentation-calcination method. The PCNNS/AP/NCDs photocatalyst exhibited excellent photocatalytic performance for the photocatalytic degradation of tetracycline (TC) under visible light irradiation at a removal rate of 90.5% in 40 min. The study of the reaction kinetics of the as-prepared samples was in accordance with the pseudo-second-order kinetics, with the correlation coefficient (R2) being greater than 0.9776. Meanwhile, the photocatalyst was capable of degrading ciprofloxacin (CIP), and showed good performance even under actual water conditions with natural sunlight irradiation, indicating that the photocatalyst has wide practical applications. In addition, the photocatalytic performance and the XRD and FTIR spectra showed no obvious changes even after four photocatalytic degradation cycles, which revealed the high stability of the PCNNS/AP/NCDs photocatalyst. Furthermore, the possible degradation pathways of TC and the possible Z-scheme mechanism were proposed with ˙O2- and h+ as the main active species contributing to photocatalytic degradation. The results provide a novel insight into the fabrication of Z-scheme PCNNS/AP/NCDs and introduce them as an efficient visible-light-responsive photocatalyst for use in practical applications.

Fabrication of Z-scheme MoO3/Bi2O4 heterojunction photocatalyst with enhanced photocatalytic performance under visible light irradiation

Constructing Z-scheme heterojunction to improve the separation efficiency of photogenerated carriers of photocatalysts has gained extensive attention. In this work, we fabricated a novel Z-scheme MoO3/Bi2O4 heterojunction photocatalyst by a hydrothermal method. XPS analysis results indicated that strong interaction between MoO3 and Bi2O4 is generated, which contributes to charge transfer and separation of the photogenerated carriers. This was confirmed by photoluminescence (PL) and electrochemical impedance spectroscopy (EIS) tests. The photocatalytic performance of the as-synthesized photocatalysts was evaluated by degrading rhodamine B (RhB) in aqueous solution under visible light irradiation, showing that 15% MoO3/Bi2O4 (15-MB) composite exhibited the highest photocatalytic activity, which is 2 times higher than that of Bi2O4. Besides, the heterojunction photocatalyst can keep good photocatalytic activity and stability after five recycles. Trapping experiments demonstrated that the dominant active radicals in photocatalytic reactions are superoxide radical (•O2−) and holes (h+), indicating that the 15-MB composite is a Z-scheme photocatalyst. Finally, the mechanism of the Z-scheme MoO3/Bi2O4 composite for photo-degrading RhB in aqueous solution is proposed. This work provides a promising strategy for designing Bi-based Z-scheme heterojunction photocatalysts for highly efficient removal of environmental pollutants.

Design and construction of Z-scheme Bi2S3/nitrogen-doped graphene quantum dots: Boosted photoelectric conversion efficiency for high-performance photoelectrochemical aptasensing of sulfadimethoxine

Rational design and fabrication of Z-scheme visible-light-driven photoactive materials have drawn much attention owing to their great potential in handling environment and energy crisis. In this work, Z-scheme Bi2S3/nitrogen-doped graphene quantum dots (NGQDs) with superior photoelectric conversion efficiency were designed and fabricated, which demonstrated enhanced photoactivity compared with Bi2S3 owing to the improved separation efficiency of photogenerated electron and hole pairs. The emphasis was put on designing Z-scheme Bi2S3/NGQDs, and then the mechanism of Z-scheme charge transfer mode was verified by the electron spin resonance (ESR) technique. On this basis, the proposed sensor exhibited a wide linear range of 0.1–120 nM and a detection limit of 0.03 nM (S/N = 3) for SDM, with high sensitivity (0.075 μA nM –1), good selectivity and stability. Moreover, the proposed PEC aptasensor using Bi2S3/NGQDs as the photoelectrode achieved sensitive and selective determination of sulfadimethoxine in milk samples. This work could provide some ideas for designing other Z-scheme photoactive species and insights into the charge transfer mechanism of Z-scheme. Furthermore, the promising applicability of PEC aptasensor using photoactive species could be extended to other accurate monitoring for contaminants.

Fabrication of Z-scheme BiVO4/GO/g-C3N4 Photocatalyst with Efficient Visble-Light Photocatalytic Performance

Fabrication of Z-scheme BiVO4/GO/g-C3N4 Photocatalyst with Efficient Visble-Light Photocatalytic Performance

Fabrication of Z-scheme Bi3O4Cl/g-C3N4 2D/2D heterojunctions with enhanced interfacial charge separation and photocatalytic degradation various organic pollutants activity

A novel Z-scheme Bi3O4Cl/g-C3N4 2D/2D heterojunctions were successfully prepared by solid phase calcination method. The Z-scheme Bi3O4Cl/g-C3N4 2D/2D heterojunctions exhibit outstanding photocatalytic activity for removing the various water contaminant under visible light, such as antibiotic, dye and heavy metal. The enhancement of phototcatalytic performance is ascribed to the interfacial interaction between 2D Bi3O4Cl nanoflakes and 2D g-C3N4 nanosheets, which can enlarge specific surface area and improve separation efficiency of photogenerated electron-hole pairs. To explain the interfacial interaction between Bi3O4Cl and g-C3N4 in Z-scheme Bi3O4Cl/g-C3N4 2D/2D heterojunctions, the transmission electron microscopy, X-ray photoelectron spectroscopy and N2 adsorption-desorption isotherms measurements were investigated. In addition, the photocatalytic mechanism over Z-scheme Bi3O4Cl/g-C3N4 2D/2D heterojunction is systematically investigated by the calculation, trapping experimental and ESR technology. The present work may provide a promising approach to fabrication of other Z-scheme 2D/2D heterojunction with efficient photocatalytic activity.

Fabrication of Z-scheme Ag3PO4/MoS2 composites with enhanced photocatalytic activity and stability for organic pollutant degradation

In this study, highly efficient visible-light-driven Ag3PO4/MoS2 composite photocatalysts with different weight ratios of MoS2 were prepared via the ethanol-water mixed solvents precipitation method and characterized by ICP, XRD, HRTEM, FE-SEM, BET, XPS, UV–vis DRS and PL analysis. Under visible-light irradiation, Ag3PO4/MoS2 composites exhibit excellent photocatalytic activity towards the degradation of organic pollutants in aqueous solution. The optimal composite with 0.648wt% MoS2 content exhibits the highest photocatalytic activity, which can degrade almost all MB under visible-light irradiation within 60min. Recycling experiments confirmed that the Ag3PO4/MoS2 catalysts had superior cycle performance and stability. The photocatalytic activity enhancement of Ag3PO4/MoS2 photocatalysts can be mainly ascribed to the efficient separation of photogenerated charge carriers and the stronger oxidation and reduction ability through a Z-scheme system composed of Ag3PO4, Ag and MoS2, in which Ag particles act as the charge separation center. The high photocatalytic stability is due to the successful inhibition of the photocorrosion of Ag3PO4 by transferring the photogenerated electrons of Ag3PO4 to MoS2. The evidence of the Z-scheme photocatalytic mechanism of the composite photocatalysts could be obtained from the active species trapping experiments and the photoluminescence technique.