Excellent Visible Light Research Articles

Carbon quantum dots modified NH2-MIL-125(Ti) acid-etching derived TiO2-based photocatalysts and efficient removal of high concentrations of dyes from wastewater under visible light

TiO2 is considered one of the most promising photocatalysts for photocatalytic treatment of dye wastewater. However, TiO2 only responds to ultraviolet light, with a small specific surface area and weak photogenerated carrier separation ability, which limit its application in the treatment of high concentration dye wastewater. In this paper, 2-amino terephthalic acid (NH2-BDC) modified TiO2 photocatalyst (NH2BDCX-TiO2) were prepared for the first time through in situ acid-etching strategy of NH2-MIL-125(Ti), and then YCQDs/NH2BDC10-TiO2 composite photocatalysts were synthesized by loading carbon quantum dots (CQDs) on its surface. The results indicated that the NH2BDCX-TiO2 photocatalyst had excellent visible light response and enhanced adsorption capacity. In addition, the successful loading of CQDs on its surface effectively enhanced the separation of photogenerated carriers and further expanded the light absorption range of the composite photocatalyst to the near-infrared region. The adsorption and photocatalytic degradation efficiency of 5CQDs/NH2BDC10-TiO2 composite photocatalyst for high concentration RhB solution (80 mg/L) reached 24.8 % and 87.1 %, respectively, which were 2.0 times and 435.5 times higher than commercial P25, respectively. Moreover, the optimum concentration of RhB solution, photocatalyst dosage and initial pH of RhB solution were also explored. Finally, based on active species capture experiments and energy band structure analysis, a possible mechanism for photocatalytic degradation of high concentration RhB solution by 5CQDs/NH2BDC10-TiO2 was also proposed. This work provided a new insight into the design of TiO2-based composite photocatalysts for the practical treatment of highly concentrated dye wastewater.

Development of bismuth-rich bismuth oxyhalides based photocatalyst for degradation of a representative antibiotic under simulated solar light irradiation

In this study, the novel 2D/2D S-scheme Bi12O15Cl6/BiOCl heterojunction was fabricated using a facile solvothermal followed by a post-thermal treatment process. The samples were characterized by various modern spectroscopy techniques. A series of Bi12O15Cl6/BiOCl heterojunctions were prepared by adjusting the molar ratio of Bi:Cl and the calcination temperature. The crystalline structure, morphology, elemental composition, and optical properties of nanocomposites strongly depend on the synthesis conditions. The sample prepared with Bi:Cl molar ratio of 2.0:1 and calcined at 400 °C (BOC-2.0-400) containing 29.55 wt% of BiOCl and 70.45 wt% of Bi12O15Cl6, exhibited the highest efficiency in the degradation of CIP solution under simulated solar light irradiation. The reaction rate constant was 2.5 times and 1.8 times higher than that of pristine BiOCl and Bi12O15Cl6, respectively. Under the experimental conditions of catalyst dosage of 0.7 gL-1, initial CIP concentration of 10 mgL-1 and pH8.8, CIP was completely degraded within 150 min of irradiation over the BOC-2.0-400. Furthermore, radical scavenging studies signified that O2●–, h+ are evolved in photocatalytic process. The experimental and characterization results provided evidenc that the excellent photocatalytic performance of Bi12O15Cl6/BiOCl heterojunction was facilitated by the construction of S-scheme charge transfer route with compact interface of 2D/2D morphology. The S-scheme Bi12O15Cl6/BiOCl heterojunction exhibited excellent visible light absorption ability, high photogenerated charge separation efficiency and maintained strong redox capacity for electrons and holes during CIP photodegradation. These findings provide a potential strategy for designing S-scheme heterojunction-based bismuth-rich bismuth oxyhalide photocatalyst to eliminate antibiotic residues.

Chitosan and TiO2 functionalized polypropylene nonwoven fabrics with visible light induced photocatalytic antibacterial performances

Chitosan/TiO2 functionalized polypropylene (CS/TiO2/PP) nonwoven fabrics were fabricated through crosslinking of chitosan with glutaraldehyde followed by loading of TiO2 nanoparticles. The functionalized CS/TiO2/PP has super hydrophilicity and excellent visible light induced photocatalytic antibacterial properties owing to the synergistic effects of CS and TiO2. The photocatalytic degradation performance was determined by assessing the degradation of methyl blue under simulated visible light irradiation and its recyclability was also evaluated. In addition, SEM images demonstrated that TiO2 nanoparticles were distributed evenly on the surface of the 2 g/L CS/TiO2/PP. Meanwhile, the polypropylene surface showed a significant increase in hydrophilicity after being treated with chitosan and TiO2. The photocatalytic degradation results revealed that CS/TiO2/PP had higher photocatalytic properties than those of pure PP under visible light, and the degradation rate of methylene blue reached 96.4 % after 90 min of light exposure. Compared to pure PP, the antibacterial properties of CS/TiO2/PP significantly increased, and the bacterial reduction percentages were increased to 98.7 % and 96.3 %, against E. coli and S. aureus, respectively. The functionalized CS/TiO2/PP composites exhibited promising potential in environmentally friendly antibacterial materials.

Cost-effective synthesis of highly-dispersed WS2 nanosheets assembled on tourmaline for improved photocatalytic activity

Tungsten disulfide (WS2) has attracted much attention in photocatalysis due to the excellent visible light harvesting and charge transfer kinetics, yet practical applications have been severely limited by the restacking property. In this work, a novel WS2/tourmaline composite was fabricated by coupling hydrothermal and calcination methods. The highly dispersed WS2 nanosheets homogeneously deposited on the tourmaline surface were revealed by electron microscopy, with sufficient exposure of the photocatalytic sites to enhance the migration efficiency of interfacial electrons. The armadillo-like WS2/tourmaline composite exhibited excellent photocatalytic activity for rhodamine B (RhB), with a degradation efficiency of 89.4 % after 150 min irradiation, while only 30.4 % was achieved by the pure WS2 microspheres. Electron paramagnetic resonance and density functional theory (DFT) calculations showed that the WS2/tourmaline composites with more sulfur vacancies preferred to produce sufficient reactive species for photocatalytic RhB degradation. In addition, photogenerated holes (h+) play a more important role in the degradation process of RhB than superoxide radicals (·O2–) and hydroxyl radicals (·OH), as confirmed by radical quenching experiments. This work presents a new option for the low-cost preparation of high-performance 2D materials via mineral assembly.

Nitrogen vacancy-induced spin polarization of ultrathin zinc porphyrin nanosheets for efficient photocatalytic CO2 reduction

Metalloporphyrin compounds have excellent electron transfer and visible light absorption ability, demonstrating broad application prospects in the field of photocatalysis. In this work, the nitrogen vacancies (NVs) were successfully introduced into zinc porphyrin (ZnTCPP) ultrathin nanosheets through surface N2 plasma treatment, which is environmentally friendly and can react in low temperatures. Furthermore, the prepared nitrogen vacancies-zinc porphyrin (NVs-ZnTCPP) materials exhibited excellent photocatalytic CO2 reduction activity and selectivity, specifically, the CO production rate of ZnTCPP-1 (N2 plasma treatment, 1 min) achieved as high as 12.5 µmol g–1h−1, which is about 2.7 times greater than that of untreated ZnTCPP. Based on the experimental and density functional theory calculation (DFT) results, it is found that the promoted photocatalytic performance of NVs-ZnTCPP could be mainly attributed to nitrogen vacancy-induced spin polarization by reducing the reaction barriers and inhibiting the recombination of photoexcited carriers. This work provides a new perspective for the construction of vacancy-based metalloporphyrin, and further explores the intrinsic mechanism between the electron spin property and the performance of the photocatalyst.

Preparation of three-dimensional porous spherical TiO2@g-C3N4 composites and visible light catalytic degradation on organic dyes

In order to improve the visible light catalytic activity of TiO2, the TiO2@g-C3N4 (TCN) composite catalysts with three-dimensional porous structure and rich active sites were prepared by hydrothermal method and calcination method orderly. The synthesized TCN composites microstructures were thoroughly characterized and their performance for the photocatalytic degradation of organic dyes was investigated. The results show that the prepared composites formed the heterojunctions with a core-shell structure, which can effectively broaden the absorption spectrum of TiO2 to visible light region. In the degradation experiments, the TCN composites exhibited excellent photocatalytic degradation effect on organic dyes, which can reach 99.65% under visible light irradiation for 2 h. The strong acid condition was benefit to the catalytic process. After five cycles of testing, the degradation efficiency of organic dyes can still maintain at 95.62% level, which indicate that the TCN composites had excellent visible light catalytic activity and reusability.

Recent Progress on Semiconductor Heterogeneous Photocatalysts in Clean Energy Production and Environmental Remediation

Semiconductor-based photocatalytic reactions are a practical class of advanced oxidation processes (AOPs) to address energy scarcity and environmental pollution. By utilizing solar energy as a clean, abundant, and renewable source, this process offers numerous advantages, including high efficiency, eco-friendliness, and low cost. In this review, we present several methods to construct various photocatalyst systems with excellent visible light absorption and efficient charge carrier separation ability through the optimization of materials design and reaction conditions. Then it introduces the fundamentals of photocatalysis in both clean energy generation and environmental remediation. In the other parts, we introduce various approaches to enhance photocatalytic activity by applying different strategies, including semiconductor structure modification (e.g., morphology regulation, co-catalysts decoration, doping, defect engineering, surface sensitization, heterojunction construction) and tuning and optimizing reaction conditions (such as photocatalyst concentration, initial contaminant concentration, pH, reaction temperature, light intensity, charge-carrier scavengers). Then, a comparative study on the photocatalytic performance of the various recently examined photocatalysts applied in both clean energy production and environmental remediation will be discussed. To realize these goals, different photocatalytic reactions including H2 production via water splitting, CO2 reduction to value-added products, dye, and drug photodegradation to lessen toxic chemicals, will be presented. Subsequently, we report dual-functional photocatalysis systems for simultaneous energy production and pollutant photodegradation for efficient reactions. Then, a brief discussion about the industrial and economical applications of photocatalysts is described. The report follows by introducing the application of artificial intelligence and machine learning in the design and selection of an innovative photocatalyst in energy and environmental issues. Finally, a summary and future research directions toward developing photocatalytic systems with significantly improved efficiency and stability will be provided.

B-TiO2/CuInS2 photocatalyst based on the synergistic effect of oxygen vacancy and Z-scheme heterojunction for improving photocatalyst CO2 reduction

Photocatalytic reduction CO2 into valuable solar fuels is a promising strategy to alleviate the greenhouse effect and the energy crisis on Earth. In this work, a B-TiO2/CuInS2 photocatalyst has been synthesized through a simple hydrothermal-calcination method for efficient reducing CO2 into CO and CH4. Boron doping and sensitization of CuInS2 ensure the excellent visible light response capacity of the composite catalyst. The synergistic effect between oxygen vacancies and Z-scheme heterojunction also endow the photocatalyst with strong carrier separation capability. Consequently, the optimized B-TO/CIS-2.5 sample exhibited the best CO (21.39 μmol g−1 h−1) and CH4 (4.83 μmol g−1 h−1) production, approximately 9 and 14 times higher than that of TO and B-TO, respectively. This study provides a reliable approach for developing photocatalysts with boosted CO2 reduction activity and high stability.

Unique roles of exfoliated bentonite in S-scheme BiOBr/Bi2MoO6 heterojunction for boosted ciprofloxacin degradation

S-scheme heterojunction retained the strong redox potential of catalysts, yet confronting severe photocorrosion and particle agglomeration, resulting in poor stability. Herein, the dual Bi-based S-scheme heterojunction supported by exfoliated bentonite (BiOBr/Bi2MoO6/BTex) was fabricated via a facile microwave hydrothermal strategy. BTex could promote the dispersion of photocatalysts and reinforce heterojunction stability through intensive surface interaction, thus reducing leakage of metal ions. The optimal BiOBr/10% Bi2MoO6/BTex exhibited excellent visible light photocatalytic performance and 94% ciprofloxacin (CIP) could be degraded within 120 min. Furthermore, the high catalytic efficiency could be maintained within the pH range from 5 to 9, and efficient degradation of tetracycline and dyes could also be achieved. Basing the analysis of band structures and determination of active species, enhanced separation and migration efficiency of photogenerated carriers could be ascribed to the synergistic effect of internal electron field (IEF) from heterojunction and surface charge repulsion from BTex. Additionally, the susceptible sites of CIP were obtained by density functional theory calculations, and three possible degradation pathways, including breakage of the quinolone ring, oxidation of the piperazine ring and defluorination were speculated combined with HPLC-MS results. With prolonging photocatalysis time, the diminished toxicity of intermediates was confirmed. This study supplied new insights to improve performance and control morphology of S-scheme heterojunctions by introducing cost-effective nature bentonite.

In-situ construction of direct Z-scheme NiO/Bi2MoO6 heterostructure arrays with enhanced room temperature ether sensing properties under visible light irradiation

Light irradiation has emerged as a promising strategy to promote room temperature sensing of resistive-type semiconductor gas sensors recently. However, high recombination rate of photo-generated carriers and poor visible light response of conventional semiconductor sensing materials have greatly limited the further performance improvement. It is urgent to develop gas sensing materials with high photo-generated carrier separation efficiency and excellent visible light response. Herein, a novel direct Z-scheme NiO/Bi2MoO6 heterostructure arrays were designed and in-situ constructed on alumina flat substrate to form thin film sensors, which realized excellent room temperature gas response towards ether under irradiation of visible light for the first time, together with excellent stability and selectivity. Based on density functional theory calculation and experimental characterization, it was demonstrated that the construction of Z-scheme heterostructure could greatly promote the separation of photo-generated carriers and adsorption of ether. Moreover, the excellent visible light response characteristics of NiO/Bi2MoO6 could improve the utilization of visible light. In addition, the in-situ construction of array structure could avoid a series of problems caused by the conventional thick film devices. The work not only provides a promising guideline for Z-scheme heterostructure arrays in promoting the room temperature sensing performance of semiconductors gas sensors under visible light irradiation, but also clarifies the gas sensing mechanism of Z-scheme heterostructure at the atomic and electronic level.

Bifunctionalization of carbon nitride by incorporation of thiophene ring and polar nickel complex to promote photocatalytic activity for hydrogen evolution

Photocatalytic performance of polymeric carbon nitride (CN) is primarily restricted by limited light utilization and poor charge separation efficiency. To this end, skeleton modification strategy was adopted by attaching thiophene ring and polar nickel complex (NiL) onto CN. The obtained bifunctionalized carbon nitride (TCN-NiL) displayed obviously elevated optical absorption and photoexcited charge separation efficiency. The NiL, with polar structure, plays as active sites like cocatalyst thus exhibited platinum-like H2 evolution activity from water splitting under visible light. The optimized photocatalytic H2 generation rate over TCN-NiL reached 136.7 μmol·h−1 without any cocatalyst, the highest rate reported so far in noble-metal-free CN-based catalysts, which is 5 times of that of CN loaded with 3 wt% Pt. Additionally, the maximum wavelength of performing H2 production capacity over TCN-NiL extends to 550 nm from 450 nm of CN, suggesting an excellent visible light absorption ability. This work provides a way for modifying CN to enhance the photocatalytic activities in a noble metal free system.

Flexible and conductive core-sheath fiber using multifunctional merocyanine as a smart electrolyte for a high-performance fibrous visible light sensor

Flexible conductive fibers have attracted significant attention in the wearable electronics field because of light weight, small size, and easy shape morphing. To date, there are few reports on multifunctional flexible conductive fibers. Finding a facile and effective solution for large-scale production of flexible conductive fibers is still a challenge. In this work, a flexible core-sheath fiber with excellent electrical conductivity (24.71 Ω·m) and visible light sensing is fabricated, which contains a merocyanine diol (MC(OH)2)/CrCl3·6H2O/ethanol aqueous solution core layer and a silicon rubber outer layer. The synthesized MC(OH)2 is an intelligent molecular switch with a visible light response that can reversibly convert from open-form MC(OH)2 to closed-form spiropyran diol (SP(OH)2) after short visible light irradiation. In the reverse process, the transition from SP(OH)2 to MC(OH)2 can occur gradually in the dark. This can be used to sense visible light in addition to electrical conductivity. The reversible change in the electrical resistance of the MC(OH)2/CrCl3·6H2O/ethanol aqueous solution reaches 15.59%. This fiber shows excellent electrical conductivity, good flexibility, a sensitive visible light response, good photochromism, a simple structure, low cost, easy preparation, and suitability for industrial large-scale production, offering promise for applications in the fields of flexible and wearable electronics.

Facile fabrication of novel In2S3–BiOCl nanocomposite-supported porous polymer monolith as new generation visible-light-responsive photocatalyst for decontaminating persistent toxic pollutants

We report synthesizing a novel p-In2S3 and n-BiOCl heterojunction nanocomposite of varying β-In2S3 stoichiometry (10–50%) fabricated via. The hydrothermal and combustion methods. In2S3–BiOCl nanocomposites were homogeneously integrated onto a porous poly(ethylene glycol dimethacrylate) monolith to serve as a high-performance visible-light-responsive renewable photocatalyst decontaminating toxic organic pollutants such as Rhodamine B. The photocatalyst's structural and surface features were characterized using ppowder X-ray diffraction, X-ray photoelectron spectrometer, high-resolution transmission electron microscopy–selected area electron diffraction, field-emission scanning electron microscopy-energy-dispersive X-ray spectral, UV–Vis-diffuse reflectance spectral, photoluminescence spectral, Fourier transforms infrared, electrochemical impedance spectroscopy, and Brunauer–Emmett–Teller/Barrett-Joyner-Halenda (BJH) analysis. Using 20 wt% of In2S3 composition in the In2S3–BiOCl nanocomposite facilitated better electron–hole pair separation with excellent visible light responsive photocatalytic activity, confirmed through electrochemical impedance spectroscopy, photoluminescence spectral and bandgap measurements. The Brunauer–Emmett–Teller/BJH analysis revealed that the In2S3–BiOCl nanocomposite-loaded poly(ethylene glycol dimethacrylate) monolith had high surface area and pore dimensions, with voluminous photoactive sites. The role of analytical parameters such as pH, nanocomposite ratio, photocatalyst dosage, dye concentration, photosensitizers/oxidizers, and light intensity were studied/optimized. Under the optimized conditions of pH 2.0, 100 mg photocatalyst dosage, 30 ppm dye concentration, 1.0 mM KBrO3, and 300 W/cm2 visible light intensity, the monolithic photocatalyst showed a dissipation efficiency of ≥98.6% for Rhodamine B in ≤0.3 h. The renewable photocatalyst can be reused for six cycles without loss in efficiency/performance and proved promising in efficiently decontaminating persistent organic pollutants at an affordable cost and time.

Snake Scale-Inspired Poly(vinylidene fluoride)/Ti3CNTx@Polypyrrole Coatings for Ultrawide-Bandwidth Microwave and Visible Light Absorption.

The accuracy of data collected by optical instruments can be greatly impacted by radar band electromagnetic waves (EM) and scattered visible light. Traditional electromagnetic-wave-absorbing (EMA) materials face challenges in effectively attenuating electromagnetic waves within the visible light spectrum. To address this issue, a structural engineering-based assembly strategy was developed to construct PVDF/Ti3CNTx@PPyNF composites with multiple heterogeneous interfaces, inspired by snake scales. And through the self-doping of N elements and the coating process, the material finally exhibits excellent microwave and visible light absorption properties. This approach generates multiple polarization losses of electromagnetic waves, enabling the material to exhibit excellent electromagnetic wave absorption performance. Specifically, the PVDF/Ti3CNTx@PPyNF composite, containing 5 wt % Ti3CNTx@PPyNFs, demonstrates exceptional microwave absorption performance, with a minimum reflection loss of -65.5 dB and an effective absorption bandwidth of up to 6.95 GHz. Additionally, the composite coating exhibits 97.4% visible light absorption performance, providing a promising solution to the challenges of protecting against complex electromagnetic environments.

Novel CoMn2O4-ZnIn2S4 hollow heterostructure cage for efficient photocatalytic hydrogen evolution

Semiconductor photocatalytic hydrogen evolution (PHE) is used to convert solar energy to hydrogen energy. Therefore, a low-cost, effective, and dependable photocatalyst could be a viable solution to environmental and energy crises. However, performing energy-conversion reactions by preparing photocatalysts with suitable photoabsorption and effective charge separation is challenging. Herein, a novel CoMn2O4-ZnIn2S4 (CMO-ZIS) hollow microcube composite catalyst with a p-n heterojunction is constructed, in which ZnIn2S4 nanosheets are grown in situ on the surfaces of CoMn2O4 hollow microcubes. Surprisingly, 10% CoMn2O4-ZnIn2S4 (CMO-ZIS-10) exhibits a PHE rate of up to 11.04 mmol h−1 g−1, which is approximately 3.6 times higher than that of pure ZnIn2S4. In addition, to maintain the excellent visible light absorption efficiency of ZnIn2S4 nanosheets, the close-contact heterogeneous interface of CMO-ZIS enables easy separation and transfer of the carriers. Furthermore, the hollow structure increases the absorption efficiency of sunlight and provides more active sites, thus increasing the reactivity of photocatalyst. In this paper, we report a workable approach for building heterojunction photocatalysts powered by water splitting.

Facet-dependent CuO/{010}BiVO4 S-scheme photocatalyst enhanced peroxymonosulfate activation for efficient norfloxacin removal

Rapid recombination of charge carriers and sluggish Cu2+/Cu+ conversion rate in Cu-based photocatalysts hinder the improvement of the peroxymonosulfate (PMS) activation efficiency. Herein, a novel S-scheme system was successfully built through hydrothermal and in-situ calcination methods to activate PMS for norfloxacin (NOR) degradation, which combined CuO with BiVO4 (BVO) containing surface heterojunction. The UV–vis spectra manifested that BVO displayed excellent visible light absorption performance after compounding with CuO, and the light absorption threshold of CuO/BVO was about 600 nm. Thanks to the existence of surface heterojunction in BVO, the photoinduced electrons, and holes would transfer to {010} and {110} facets, respectively. The construction of S-scheme heterojunction further facilitated the accumulation of electrons on CuO, thus realizing the spatial separation of charge carriers. In addition, the electrons gathered on the CuO expedited the Cu2+/Cu+ cycle, thereby improving the activation efficiency of PMS. On this basis, the NOR removal capacity of 5CuO/BVO composites was obviously enhanced, which was 3.65 and 2.45 times that of CuO and BVO. Moreover, the influence of ambient pH and PMS dosage on the photocatalytic performance of CuO/BVO was investigated. Through the analysis of NOR degradation pathways and degradation products, it was found that the toxicity threat of NOR to the environment was reduced during the degradation process. According to the XPS results, forming the S-scheme heterojunction accelerated the Cu2+/Cu+ redox cycle during the PMS activating process. Meanwhile, photoluminescence (PL) and time-resolved photoluminescence (TRPL) analysis demonstrated that the CuO/BVO composites exhibited eminent ability for charge separation. The possible mechanism of charge transfer was assumed by exploring reactive species and the energy band structure of catalysts. To sum up, this research provides a new perspective on boosting PMS activation to purify antibiotics in water.

Fabrication of hybrid polyaniline – Polyoxometalate decorated with ZrO2 ternary nanocomposites with excellent visible light driven photocatalytic performance

The significant environmental concerns need the extensive fabrication and design of efficient visible light responsive photocatalysts materials. The objective of this research is to develop a highly efficient ternary polyaniline – phosphotungstic acid @ZrO2 nanohybrid photocatalyst for use in visible light. polyaniline – phosphotungstic acid @ZrO2 nanohybrids were successfully synthesized by chemical oxidative polymerization method and characterized. The XRD analysis confirms the formation of monoclinic zirconia phase crystalline polymer while HR-SEM and HR-TEM results reveals that polymers were grown on the surface of Phosphotungstic Acid-Zirconia and contributes to visible light absorption property. The photocatalytic activity of Polyaniline (PANI)/Phosphotungstic acid (PTA)-Zirconia (ZrO2) nanohybrids was studied using methylene blue (MB) dye, p-Nitrophenol (PNP), 2, 4-dichlorophenoxyaceticacid (2, 4-D) as toxic pollutants. It is found that, PANI/PTA-ZrO2 (3:1) shows enhanced photocatalytic activity.

The Construction of p/n-Cu2O Heterojunction Catalysts for Efficient CO2 Photoelectric Reduction

Cu2O is a p-type direct bandgap semiconductor with a band gap of 2~2.2 eV, which has excellent visible light absorption and utilization. However, slow charge transfer and poor stability hinder its practical application. In this paper, a facile electrodeposition approach successfully synthesized the heterostructure of p-Cu2O and n-Cu2O. The protective layer of n-Cu2O on the surface of p-Cu2O nanoparticles forms a p/n heterojunction. Due to the p/n heterojunction, the PEC performance of p/n-Cu2O is enhanced significantly. The charge separation efficiency of photogenerated electron/hole pairs in p/n-Cu2O is greatly improved. Therefore, p/n-Cu2O shows superior photoelectrochemical (PEC) CO2 reduction reaction (CO2RR) efficiency when used as a photocathode.

BiVO4 As a Sustainable and Emerging Photocatalyst: Synthesis Methodologies, Engineering Properties, and Its Volatile Organic Compounds Degradation Efficiency.

Bismuth vanadate (BiVO4) is one of the best bismuth-based semiconducting materials because of its narrow band gap energy, good visible light absorption, unique physical and chemical characteristics, and non-toxic nature. In addition, BiVO4 with different morphologies has been synthesized and exhibited excellent visible light photocatalytic efficiency in the degradation of various organic pollutants, including volatile organic compounds (VOCs). Nevertheless, the commercial scale utilization of BiVO4 is significantly limited because of the poor separation (faster recombination rate) and transport ability of photogenerated electron-hole pairs. So, engineering/modifications of BiVO4 materials are performed to enhance their structural, electronic, and morphological properties. Thus, this review article aims to provide a critical overview of advanced oxidation processes (AOPs), various semiconducting nanomaterials, BiVO4 synthesis methodologies, engineering of BiVO4 properties through making binary and ternary nanocomposites, and coupling with metals/non-metals and metal nanoparticles and the development of Z-scheme type nanocomposites, etc., and their visible light photocatalytic efficiency in VOCs degradation. In addition, future challenges and the way forward for improving the commercial-scale application of BiVO4-based semiconducting nanomaterials are also discussed. Thus, we hope that this review is a valuable resource for designing BiVO4-based nanocomposites with superior visible-light-driven photocatalytic efficiency in VOCs degradation.

Microstructure FSS patterning to improve 5G microwave signals through low-e plastic windows

Low emissivity (low-e) windows are widely used in the architectural sector to block the infrared (IR) radiation from the Sun. The windows contain a multilayer nanoscale coating of metallic and dielectric layers. The metallic layer, which is responsible for the IR reflection, also attenuates the radio and microwave frequencies used for modern-day technologies such as Fifth Generation (5G) communications. As there is an ever-increasing demand for a reliable interior-to-exterior signal coverage, low-e windows should be transparent to such signals. A class of surface modification — Frequency Selective Surface (FSS) is the technique of choice to be applied on the thin metallic coating to transmit the wireless signal.In this work, a thin silver (Ag) film — 10 nm thick was deposited by electron beam evaporation on polycarbonate substrates as an example low-e coating. Despite excellent IR blocking (64 %) and visible light transmittance (60 %), it also presented a high attenuation of 20 dB at 5G signal bands (72–82 GHz).​ FSS patterns of various geometries and sizes were applied via laser ablation and evaluated to provide the lowest attenuation. We demonstrated that the application of the hexagonal pattern provided largest improvement reducing the 5G attenuation value from 20 dB to 1 dB, without compromising the visible transmittance and having only a minor effect on IR reflection.