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Graphitic carbon nitride (gCN) has shown great potential in photocatalysis. Developing suitable cocatalysts is a critical way to enhance gCN's photocatalytic performance. In this paper cobalt–nickel bimetallic phosphide (CoNiP) was used as a cocatalyst to modify gCN. A gCN/CoNiP composite was successfully prepared by a simple hydrothermal method. XRD, XPS, SEM, UV-vis DRS, and PL characterization studies showed that a Schottky junction-like structure was constructed between gCN and CoNiP, which intensified the visible light response, enhanced the charge transfer rate and prohibited the recombination of photogenerated carriers, thus significantly improving gCN photocatalytic activity. Under simulated sunlight, the removal efficiency of methylene blue (10 mg L−1) was 97.8% by 120 min of irradiation, 44.6% higher than that of gCN. The quenching experiment showed that ˙O2−, ˙OH and h+ were the main active species. Based on the above points, the possible mechanism of photocatalysis was deduced. [ABSTRACT FROM AUTHOR]

In this paper, three-dimensional TiO2 nanoflowers (NFs) were prepared by a facile hydrothermal method, and Ag3PO4 was grown in situ following alkali treatment to design and synthesize a Ag3PO4/OH/TiO2 catalyst with excellent photocatalytic activity under visible light. The test results show that the photocatalytic degradation performance of TiO2 NFs after alkali treatment and Ag3PO4 loading is significantly improved. This is because the alkali treatment and the introduction of Ag3PO4 can provide a large amount of –OH, which can be converted to ˙OH under UV irradiation, followed by an increase in the number of active radicals to enhance the photocatalytic degradation performance. Meanwhile, the introduction of Ag3PO4 can effectively improve the light absorption ability of the photocatalyst. Moreover, the in situ growth of Ag3PO4 on TiO2 NFs can construct a high-quality Ag3PO4/TiO2 heterojunction to promote the charge separation and transport. Therefore, the degradation rate of Ag3PO4/OH/TiO2 can reach 90% after 30 min for degrading 3 mg L−1 RhB under visible light. The Ag3PO4/OH/TiO2 photocatalyst designed in the present work provides a new tool for the degradation of organic dyes. [ABSTRACT FROM AUTHOR]

Enhancing the piezoelectric polarization strength of materials to promote the photogenerated carrier separation is of great significance for piezoelectric polarization-assisted photoelectrochemical (PEC) water splitting. In this paper, P-BiFeO3 composite photoelectrodes were synthesized by modifying BiFeO3 photoelectrodes with phosphate ions. The maximum photocurrent density of the P-BiFeO3 composite photoelectrodes could reach 0.87 mA cm−2 at 1.23 V vs RHE, which is significantly enhanced compared to the BiFeO3 photocurrent. The enhanced photoelectrochemical activity of the phosphate ion-modified BiFeO3 photoelectrodes may be attributed to the increased visible light absorption and larger active area due to the presence of phosphate groups. Furthermore, the photocurrent density of the P-BiFeO3 composite photoelectrodes after the introduction of the piezoelectric polarisation field reached 2.58 mA cm−2 at 1.23 V vs RHE, which was 2.2 times higher than that of BiFeO3 (1.17 mA cm−2). The presence of phosphate groups on the surface of BiFeO3 photoelectrodes can improve their asymmetry and increase their piezoelectric polarisation intensity, further enhancing the PEC water splitting performance of the material. This study provides a strategy for the design of highly active photoanodes with ionic modification to enhance the piezoelectric polarisation of the material to improve PEC water splitting. [ABSTRACT FROM AUTHOR]

Promoting the separation of photoelectrons and holes can enhance the photocatalytic performance of photocatalysts. The combination of photocatalysts with piezoelectric materials is an effective way to improve the photocatalytic performance. In this paper, the heterogeneous structure of PZT/Ag2O is proposed, which can effectively improve its photocatalytic degradation performance through the piezoelectric effect. RhB degradation experiments were conducted under ultrasonic vibration and visible light irradiation to evaluate the photocatalytic performance of PZT/Ag2O. It is worth noting that PZT/Ag2O showed excellent piezo-/photocatalytic activity, and the degradation rate of RhB within 60 min was 96.31%, which was higher than those achieved under ultrasonic vibration (55.98%) and visible light irradiation (65.14%). The improved performance is due to the heterojunction construction widening the optical response range, while the piezoelectric effect provides a built-in polarization field to improve the separation efficiency of photogenerated electrons and holes. This study provides an efficient and feasible piezo-/photocatalyst for the treatment of pollutants. It is helpful to understand the mechanism of the piezoelectric effect and improve the photocatalytic performance. [ABSTRACT FROM AUTHOR]

BiVO4, as a visible light catalyst, produces photogenerated electrons and photogenerated holes that are easy to recombine. In this paper, a BiVO4/Ag2O composite was prepared to promote the separation of photogenerated carriers of BiVO4. Compared with BiVO4, the properties and photocatalytic activity of BiVO4/Ag2O were obviously improved. The improvement of BiVO4/Ag2O was reflected in the better separation of photogenerated electrons and photogenerated holes, higher UV-visible maximum absorption wavelength, and stronger ability to degrade doxycycline. The effects of Ag2O on the crystal structure, the morphology and the binding energy of BiVO4 were analyzed by XRD, XPS and SEM, and the existence of a heterojunction in BiVO4/Ag2O was confirmed. The results of capture experiments showed that the photocatalytic processes of BiVO4 and BiVO4/Ag2O produced hydroxyl radicals (˙OH), holes (h+) and superoxide radicals (˙O2−). However, the contribution of active species was different in the two systems. The degradation pathways and intermediate products of doxycycline were analyzed by UPLC-QTOF. This work proposed a new method for the preparation of BiVO4/Ag2O particles with remarkable photocatalytic activity, and provided a reference for the degradation of doxycycline. [ABSTRACT FROM AUTHOR]

The heterojunction structure of semiconductor photocatalysts is significant for making full use of their capabilities for organic molecules and dye degradation. In this paper, we present a heterogeneous junction composite fabricated with hybrid phase TiO2 and g-C3N4 for methylene blue (MB) removal through adsorption and photocatalytic degradation. The heterogeneous junction system was prepared by hydrothermal treatment with a subsequent pyrolysis process. The variation of the proportion and lattice structure of hybrid phase TiO2 in the synthesized catalysts was analyzed by refinement. Adsorption experiments showed that the maximum adsorption capacity of TiO2/g-C3N4 (1 : 10) was 1667 mg g−1, which was 45.97 times and 63.78 times higher than that of TiO2 and g-C3N4, respectively. In the photodegradation process, the TiO2/g-C3N4 (1 : 10) photocatalyst shows a removal rate of MB of 100 mg L−1, which was as high as 96.262%, significantly higher than that of pure TiO2 and g-C3N4. Brunner–Emmett–Teller (BET) measurements and Fourier transform infrared spectroscopy (FTIR) showed that the adsorption of MB onto TiO2/g-C3N4(1 : 10) was chemical adsorption, and ˙OH, which acts as an active substance, was found to play a major role in the photocatalytic degradation process. Overall, the developed hybrid phase TiO2/g-C3N4 heterojunction composite may be beneficial for the treatment of water pollution. [ABSTRACT FROM AUTHOR]

Visible light irradiation of the readily available sandwich complex [(C5H5)Fe(C6H6)]BF4 with multidentate salicylate dyes such as Aluminon, Alumocresone, Chrome Azurol S, or Eriochrome Cyanine R produced intesively colored iron(III) complexes. Similar reaction can proceed on paper, cotton, or polyacrylamide hydrogel to give colored pH-sensitive patterns. [ABSTRACT FROM AUTHOR]

In this paper, a series of BN/NTCDA photocatalysts have been prepared using a simple calcination method and their photocatalytic performance under visible light irradiation is studied with tetracycline (TC) as the target pollutant. When the ratio of BN and NTCDA is 100 : 1 and the temperature is 350 °C, the sample (BN/NTCDA (100 : 1)) has the highest adsorption efficiency (28.65%) and photodegradation efficiency (51.54%) for TC. The characterization results of XRD, FTIR, XPS, TEM, and 1H NMR show that BN/NTCDA (100 : 1) is a BN-based photocatalytic material, which is likely formed through the reaction of the surface hydroxyl group of BN and the anhydride of NTCDA. The band gap of BN is about 4.11 eV, and the band gap of NTCDA is 2.67 eV. So, the electron is firstly excited from the VB of NTCDA to its CB, and then the electron in the VB of BN is excited into the empty VB of NTCDA, implying that TC is degraded by photoactive species (˙O2−, h+ and ˙OH) from the VB of BN and CB of NTCDA. The capture experiment of photoactive species suggests that ˙O2− makes the main contribution to TC photodegradation, followed by h+, ˙OH. After five recycle experiments, BN/NTCDA (100 : 1) still has 77.32% removal efficiency for TC. The removal efficiency (80.19%) of BN/NTCDA (100 : 1) is higher than that of TiO2 (75.63%) and g-C3N4 (24.44%). This work contributes to the development of novel metal-free-photocatalysts and the application of photocatalytic technology to the removal of antibiotics. [ABSTRACT FROM AUTHOR]

In this paper, Eu/F co-doped bismuth vanadate photocatalysts with different doping ratios were prepared by a hydrothermal method, and their microscopic morphology, crystal structure, light absorption and photocatalytic performance were investigated. Part of the F in the Eu/F co-doped samples might be doped to replace O in the BiVO4 lattice, while Eu3+ ions replaced Bi3+ ions, which led to a difference in the morphology and internal structure. XRD and Raman spectroscopy characterization showed that the crystal structures of the samples were all monoclinic scheelite type, and contained a certain tetragonal scheelite type, and the crystallinity was good. The Eu/F co-doped samples exhibited better photoactivity under UV-Vis light. The recombination rate of the photogenerated carriers in the Eu/F co-doped samples was obviously reduced, but it showed a serious concentration dependence on the doping species. Under visible light irradiation, Eu/F co-doped samples (R = 0.75) had the best degradation effect on methylene blue (MB). In addition, the degradation mechanism of the photocatalyst was also explored. ˙O2− and h+ were the main active species affecting the degradation of MB by Eu/F–BiVO4. [ABSTRACT FROM AUTHOR]

BiOCl has garnered considerable attention recently. However, its relatively wide bandgap and poor separation efficiency of charge carriers limit its application in the visible light range. Introducing oxygen vacancies (OVs) and constructing heterojunctions are both considered as viable modification approaches. In this study, oxygen vacancy-rich BiOCl/Bi24O31Cl10 heterojunctions were synthesized using glycine as the fuel by a one-pot self-propagation method. Variations in the amount of fuel led to differences in OV concentration and heterojunction composition in the prepared samples. The XRD pattern, FTIR spectra and EDS confirmed the formation of BiOCl/Bi24O31Cl10 heterojunctions. The XPS and ESR spectra proved the existence of oxygen vacancies. The BET results showed that the sample prepared with an appropriate amount of glycine exhibited a larger specific surface area. The most effective OVs-BiOCl/Bi24O31Cl10 composite demonstrated improvements in degrading rhodamine B (RhB), showing 8.09 and 17.96 times greater efficiency compared to BiOCl and Bi24O31Cl10, respectively. It achieved 93% dye degradation within 30 minutes. [ABSTRACT FROM AUTHOR]

Latent fingerprint (LFP) detection is an important tool in criminal offense detection. Nowadays, ultraviolet (UV) excited visible emission phosphors are widely used in LFP detection; however, due to the shortcomings of UV excitation (λex < 270 nm) such as low power, high price, and susceptibility of visible light to the influence of natural light, their application in LFP detection is restrained. Here, a new idea is proposed: the use of blue light-excited near-infrared (NIR) emitting phosphors as a tool for fingerprint detection visualization. To this end, in this work, a series of blue-excited (λex = 467 nm) NIR phosphors Ca(1−x)SrxO:Eu2+ (x = 0–0.2) were designed based on CaO:Eu2+ by using the crystal field engineering strategy. When x = 0.2, the luminescence center is red-shifted from 733 nm to 783 nm, and the full width at half maximum (FWHM) is broadened from 100 nm to 156 nm, and the red-shift and broadening of the spectrum greatly improve the accuracy of fingerprint detection. Finally, Ca0.8Sr0.2O:0.1%Eu2+ gives high-quality visualized fingerprints in LFP detection, which is a good solution to the problems faced by UV-excited visible-emitting phosphors in LFP detection. Not only that, a NIR phosphor-converted light-emitting diode (NIR pc-LED) was prepared by combining Ca0.8Sr0.2O:0.1%Eu2+ with a blue LED chip, which was verified to have the potential for applications in biological tissue penetration and night vision illumination. This work introduces a new idea for the detection of a LFP and demonstrates that rationalizing the local structure around Eu2+ is an effective strategy for exploring Eu2+-doped NIR luminescent phosphors. [ABSTRACT FROM AUTHOR]

The development of advanced efficient and durable non-precious metal-based anode catalysts for photo-assisted direct methanol fuel cells remains a significant challenge. In this study, Ce-doped Co3O4 (Ce–Co3O4) was prepared by a three-step process involving hydrothermal synthesis, cation exchange and calcination. The introduction of Ce can not only induce more Co3+ with oxidation properties, but also expand the light absorption range and improve the separation efficiency of photogenerated electron–hole pairs. In an alkaline solution and under visible light irradiation, Ce–Co3O4 showed high current density (31.4 A g−1), high photo-response current (3.52 A g−1) and good long-term stability (the current density retention was 82% after 13 h under visible light irradiation). The reaction mechanism for the photo-assisted methanol oxidation was investigated by a series of optical characterization studies (UV-vis diffuse reflectance spectroscopy, Mott–Schottky, photoluminescence spectroscopy, and electron paramagnetic resonance). The results indicated that the strong oxidative photogenerated hole (h+), ˙OH, and ˙O2− were beneficial for the oxidation of methanol and COads. This study provides a good idea for the design of efficient non-precious metal based anode catalysts for photo-assisted direct methanol fuel cells. [ABSTRACT FROM AUTHOR]

Visible-light active heterogeneous photocatalysts offer various advantages owing to their ability to exploit clean, renewable, and economically viable visible light as a driving force. This study aims to develop such photocatalysts by incorporating various loadings (10, 20, and 30 wt%) of bismuth tungstate (Bi2WO6 or BWO) into graphitic carbon nitride (g-C3N4 or CN) nanosheets. The CN nanosheets and BWO nanomaterials are synthesized using an eco-friendly hydrothermal method. The objective is to evaluate the photocatalytic activity of these catalysts for the Knoevenagel condensation reaction under 12 W blue LED light (low power), aiming to outperform the activity of pure CN. Various characterization methods, including XRD, UV-vis DRS, FTIR, PL, XPS, and TEM, are employed to analyze the catalysts. The study specifically focuses on the performance of the various BWO loading percentages on CN nanosheets. Among those, 20 wt% BWO loaded CN achieves a yield of 80% with minimal activity decline over five recyclability cycles. Furthermore, this study identifies that BWO/CN follows a Z-scheme pathway, enhancing the photocatalytic performance and facilitating organic transformations. Scavenging experiments confirm the formation of radicals during photocatalysis, validating the proposed mechanism and providing crucial mechanistic insights. Ultimately, this research seeks to highlight BWO/CN as a promising, environmentally friendly photoactive substance with significant potential for effective photocatalytic use. To our knowledge, this is the first study to use BWO/CN catalysts for the Knoevenagel condensation reaction under blue LED irradiation. [ABSTRACT FROM AUTHOR]

This method describes the iron-promoted amidation of dioxazolone under visible light to obtain aromatic/alkyl substituted amides. The nitrogen radicals formed during this process undergo hydrogen atom transfer (HAT) to form amides through the proton provided by HBpin. This reaction eliminates the need for external chemical oxidants and expensive photocatalysts, and exhibits compatibility with various aryl/alkyl substituted derivatives. This method has good prospects for application and development in organic synthesis and medicine. [ABSTRACT FROM AUTHOR]

In this work, based on the electrostatic adsorption theory, a direct Z-scheme NH2-UiO-66/BiOCl composite photocatalyst was prepared by a one-step solvothermal method with NH2-UiO-66 embedded on the smooth surface of flower-like BiOCl without additional chlorine source to form a close contact interface. The photocatalytic degradation of tetracycline hydrochloride (TCH) of 1.0-NH2-UiO-66/BiOCl(1.0-NUBC) prepared under simulated sunlight was 1.63 times and 78.84 times that of pure BiOCl and pure NH2-UiO-66, respectively. The reason for the enhanced photocatalytic performance may be that electrostatic adsorption promotes the homogeneous and orderly synthesis of heterogeneous structures, significantly increasing the ratio of NH2-UiO-66/BiOCl surface, which not only improves the visible light response range but also promotes the formation of the interface electric field between NH2-UiO-66 and BiOCl interface. The separation and transfer of the photogenerated electron–hole pairs are greatly promoted. Therefore, this study provides an effective way for the synthesis of BiOCl/MOF composites and has a good application prospect. [ABSTRACT FROM AUTHOR]

The development of high-efficiency photocatalytic materials responsive to visible light is one of the most effective ways to address the environmental threats posed by organic dyes in industrial wastewater. In this paper, novel visible-light-responsive nitrogen–sulfur co-doped carbon quantum dots modified ZnO (ZnO/N,S-CQDs) composites with a significantly enhanced photocatalytic degradation performance of Rhodamine B (RhB) were successfully synthesized. Under visible light, the photocatalytic degradation efficiency reached 98.7% over the optimal composite. Besides, the degradation obeyed the pseudo-first-order kinetics model with a photocatalytic rate constant (k) of 0.0473 min−1, which was around 3.71 times higher than that of pure ZnO nanoparticles (0.01273 min−1). In addition, the morphology, size and elemental composition of the ZnO/N,S-CQDs were characterized using TEM, SEM, XRD, FT-IR, and XPS which confirmed the successful synthesis of the composites. Photoluminescence (PL) and transient photocurrent response results indicated an increase in the carrier separation efficiency of ZnO/N,S-CQDs. Based on the active species removal experiment, superoxide radicals (˙O2−) played a leading role in the photocatalytic reactions and a possible photocatalytic degradation mechanism was revealed. These further demonstrate that the N,S-CQDs with varying properties contributed significantly to the enhanced photocatalytic activity of ZnO. Overall, the present method follows the principle of green economy, and novel N,S-CQDs provide a feasible approach for the development of photocatalytic performance of ZnO. [ABSTRACT FROM AUTHOR]

In this study, Z-scheme Cr2O3–Fe3O4/C hetero-nanostructure polyhedra are prepared using the amine-functionalized metal–organic framework NH2-MIL-101(Fe) as the precursor through a simple hydrothermal method and impregnation–calcination route. Systematic characterization was conducted on the phase structure, morphology, optical/electrochemical properties and the photocatalytic performance exhibited by the magnetic Cr2O3–Fe3O4/C samples. As observed from the results, Congo red (CR) degradation rates of the magnetic polyhedron-like Cr2O3–Fe3O4/C hetero-nanostructures under visible light are found to be nearly 1.86 and 1.21 times higher than those achieved by Cr2O3 and Fe3O4/C samples, respectively. Complying with the results achieved by the active specie tests, superoxide radicals could be the major active species in the CR photocatalytic degradation due to graphite carbon with high conductivity. On this basis, a model Z-scheme photogenerated carrier transfer system was developed. In the present paper, an approach for developing and designing Z-scheme hetero-nanostructure photocatalysts for purifying wastewater is presented. [ABSTRACT FROM AUTHOR]

In this paper, a novel pristine carbon nitride (np-CN) with hollow capsule-like morphology was facilely prepared by the thermal polymerization of melamine and cyanuric chloride at 550 1C in air for 4 h. Then, modified carbon nitride (CN-P4mg) micro-flakes with zigzag edges were synthesized by the copolymerization of melamine, cyanuric chloride, and triaminotriphenylamine with a mass fraction of 0.13%. Analysis of the microstructure, surface state, porosity, and optoelectronic properties of the two samples indicates that CN-P4mg has a larger specific surface area and a lower bandgap than np-CN. Under visible light, CN-P4mg displays enhanced photocatalytic performance for the generation of hydrogen compared to that of np-CN and bulk graphite carbon nitride (g-C3N4). The photocatalytic hydrogen evolution rate of CN-P4mg reaches 16897.3 mmol g-1 h-1, which is 1.84 times that of np-CN and 72 times that of bulk g-C3N4. The experimental results confirm that the addition of triaminotriphenylamine provides a modified design for developing metal-free carbon nitride derivatives and a new route to study efficient photocatalytic materials. [ABSTRACT FROM AUTHOR]

In this paper, we designed and synthesized a novel pH and NIR light responsive UCNP/TiO2/Cur@ZIF-8 nano-composite. The newly synthesized nano-platform was characterized using spectroscopic methods. Here, upconversion nanoparticles (UCNPs) and titanium dioxide nanoparticles (TiO2 NPs) were encapsulated to upconvert energy through the photosensitizing phenomenon where the chemotherapeutic agent curcumin (Cur) and TiO2 synergistically achieved therapeutic effects. At first, ZIF-8 decomposed in the acidic microenvironment of tumors that assisted TiO2 NPs to efficiently convert the irradiated near infrared (NIR) 808 nm light into UV visible light, thus producing a large number of reactive oxygen species to effectively inhibit tumor growth. Furthermore, in vitro and in vivo data demonstrated that UCNP/TiO2/Cur@ZIF-8 is an excellent nanoplatform that can be used as NIR-mediated photodynamic as well as chemotherapeutic therapy for tumors. [ABSTRACT FROM AUTHOR]

A novel CdS@TiO2@C/Ti3C2 composite as a high-efficiency photocatalyst for the degradation of tetracycline hydrochloride (TC-HCl) was fabricated by in situ oxidizing two-dimensional (2D) layered transition metal Ti3C2 MXene and subsequently compounding with CdS nanoparticles (NPs) via a two-step hydrothermal method. Benefitting from the in situ oxidation of Ti3C2 MXene, the derived TiO2@C/Ti3C2 composites possess excellent interface contact and uniform morphology distribution. Furthermore, the in situ grown TiO2 displays a nanosheet (NS) structure with high-energy (001) facets, which could bring about unique surface heterojunctions between the (101) and (001) facets of the TiO2 NSs. On the above basis, CdS NPs are introduced to effectively improve the light-harvesting ability in the visible region due to the narrow band gap and enlarged surface area. Meanwhile, the separation and transfer efficiencies of photo-generated carriers are significantly enhanced by the synergistic effect of the C/Ti3C2 matrix, surface heterojunctions of the TiO2 NSs and heterojunctions of CdS/TiO2. Therefore, the CdS@TiO2@C/Ti3C2 composites display remarkably enhanced photocatalytic ability for TC-HCl degradation under the irradiation of visible light, and the CdS@TiO2@C/Ti3C2-2 sample exhibits optimal photodegradation efficiency with a value of 85% within 60 min, which is 8.5 times higher than that of the TiO2@C/Ti3C2 sample. Additionally, the corresponding improved mechanism is also deeply discussed in the present paper. [ABSTRACT FROM AUTHOR]

Comprehensive strategies with the development of advanced materials are required for the remediation of water and land pollution to protect the environment and human health. In this regard, iron oxide catalysts are recognized as preferable catalysts for the heterogeneous photo-Fenton process, which is an efficient technique for degrading organic pollutants in waste water. The present study discusses the photocatalytic performance of iron oxide-based catalysts synthesized from industrial waste red mud for methylene blue degradation under visible light irradiation. XRD studies confirmed the formation of a pure α-Fe2O3 (hematite) phase, whereas the doping of iron oxide with Mn, Cu, and Ce was ascertained by XPS analysis. 3 wt% Cu doped iron oxide with a TOC value of ∼84.7% showed the best removal efficacy to the tune of ∼91% within 60 min of visible light irradiation. Impedance data supports the enhanced charge separation in metal doped α-Fe2O3, which improves the photocatalytic performance. A similar trend was observed in photo-electrochemical (PEC) properties, where Cu doped Fe2O3 showed 2 times higher photocurrent than the bare one. Based on scavenging tests, electrons and hydroxyl radicals (˙OH) were shown to be major players in the photodegradation of pollutants under visible light. A probable mechanism explaining the enhanced e−/h+ pair separation and migration was proposed by examining electrochemical properties. This work has significant implications for wastewater treatment with the efficient use of industrial waste red mud as a cost-effective resource. [ABSTRACT FROM AUTHOR]

It is essential to design and fabricate semiconductor-based photocatalysts with excellent activity to split H2O into H2 and O2 using sunlight because of the depletion of fossil resources and environmental pollution. LaVO4 is a visible light catalyst with a narrow band gap, satisfactory stability, and a low price. Therefore, in this work, alkali metal-doped LaVO4 was manufactured. Alkali metal-modified LaVO4 was prepared by a hydrothermal method as a photocatalyst for water splitting under visible light illumination, and a series of characterizations was carried out. The results showed that alkali metal doping improved the catalytic performance of pure LaVO4 and mainly optimized the hydrogen and oxygen production of Na-doped LaVO4 so that a maximum H2 and O2 evolution of 2.83 and 0.71 mmol g-1 h-1, respectively was obtained. The superior photocatalytic activity of Na-doped LaVO4 was mainly attributed to synergistic effects, including the extended visible-light response and improved charge separation. This study provides a new idea for the design of a highly efficient LaVO4-based water-cracking photocatalys.t. [ABSTRACT FROM AUTHOR]

The fabrication of environmentally friendly materials for wastewater remediation represents a promising approach. Thus, we present the fabrication of nanostructured CoFe2O4 (CF) particles entangled within a hydrogel-based matrix composed of carboxy methyl cellulose-psyllium-RGO (CPRHG/CF). The functionality, composition, and nature of the fabricated composite were characterized using FTIR, XRD, and XPS techniques. Furthermore, the internal and surface morphology was analyzed through FE-SEM and HR-TEM imaging. To assess the photo activity, UV-Vis and photoluminescence (PL) spectroscopy were employed, confirming that CPRHG/CF exhibits significant potential for light absorption in the visible spectrum while minimizing the charge recombination rate. The fabricated CPR/CFHG composite hydrogel was employed for the removal of pharmaceutical effluent, tramadol (TMD), via both adsorption and photocatalysis processes. In batch adsorption experiments lasting 2 hours, the composite hydrogel demonstrated impressive adsorption efficiency of 92.93% and a maximum adsorption capacity of 89.97 mg g-1. Subsequently, during photocatalytic treatment under 1 h of solar illumination, approximately 90.36% of the TMD was successfully degraded. The degradation process followed a pseudo-firstorder kinetics model with a rate constant (k1) of 0.0380 min-1. Furthermore, the investigation of reactive oxygen species (ROS) has identified superoxide radicals (O2 -) as the major species responsible for the degradation process, which was confirmed through radical scavenging experiments. [ABSTRACT FROM AUTHOR]

The most effective approach to develop new photocatalysts involves solar activation and prevention of the recombination of photogenerated hole–electron pairs. To achieve these goals, in this work, a series of bismuth oxyiodide and graphene oxide (BiOI/GO) composites were synthesized by a simple ex situ method. The structural, morphological, optical, and electrical properties of the synthesized compounds were thoroughly investigated. The photooxidation reaction of NO in the gas phase under visible light irradiation was used to assess the photocatalytic activity of BiOI/GO composites. The results showed that a small amount of GO significantly improved the photocatalytic activity. The BiOI/GO-0.5% sample prepared with 0.5 wt% GO showed the highest NO conversion (∼100%), indicating excellent photocatalytic stability after four continuous irradiation cycles and a high selectivity of 97% for nitrate ion formation. The increase in photocatalytic activity was mainly related to increased light absorption, high specific surface area, and better separation of light-generated charges. The use of chemical scavengers contributed to clarifying certain aspects of the possible photooxidation process of NO, which demonstrated that superoxide radicals (˙O2−) could be the main factor responsible for the photodegradation of NO by BiOI/GO-0.5%. [ABSTRACT FROM AUTHOR]

TiO2/rGO (TG) composites were synthesized using a hydrothermal reduction method, with titanium dioxide and graphene as the starting materials. Subsequently, dye-sensitizing titanium dioxide/graphene photocatalytic composites, named DTG and APTG, were prepared by covalently attaching C.I. Direct Black 17 or C.I. Acid Violet 3 dye onto TG. The composites were characterized using FTIR, TEM, UV-vis DRS, EDS, and Raman spectroscopy. The EDS surface scanning results of APTG and D2.70TG composites have shown that Ti and S atoms are uniformly distributed on the graphene sheets. The presence of characteristic peaks for S2p and N1s near 166 eV and 399 eV in D2.70TG and APTG was intensified compared to those of TG composites. The grafting rate reached its peak when the amount of C.I. Direct Black 17 was 2.70 and the fixed amount of TG was 0.1 g. The UV-vis diffuse reflectance spectroscopy study results demonstrated a shift in the response range to visible light after dye modification for DTGs and APTG. Photocatalytic experiments showed that D2.70TG was capable of removing over 99% of MB within 1 hour. Furthermore, after 5 cycles of photocatalytic experiments, the removal rate of MB remained at above 95%. [ABSTRACT FROM AUTHOR]

This study developed an efficient photocatalyst for hydrogen production, consisting of CdS nanorods and the CoTPPBr4 co-catalyst. The synthesized photocatalyst was characterized using a suite of techniques including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), photoluminescence (PL) spectroscopy, and ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS). Additionally, transient photocurrent response and electrochemical impedance spectroscopy (EIS) were carried out to further probe the material's properties. Our findings demonstrate that the CoTPPBr4 co-catalyst significantly enhances the photocatalytic H2 evolution efficiency under visible light irradiation. Notably, among the tested photocatalysts, a 12.5% CoTPPBr4/CdS composite exhibited the most superior photocatalytic performance, achieving a hydrogen production rate of 41.3 mmol g−1 h−1, which is 4.1 times higher than that of pristine CdS. The introduction of CoTPPBr4 effectively facilitates charge transfer within CdS, enhances the separation efficiency of light-induced electron–hole pairs, and boosts the surface H2-evolution kinetics. This research not only introduces a promising photocatalyst for visible light-driven hydrogen production but also provides a way for the development of highly efficient and stable CdS-based hybrid semiconductor nanocomposites suitable for diverse photocatalytic applications. [ABSTRACT FROM AUTHOR]

The presence of antibiotics in aquatic systems poses a significant risk to both the ecological balance and human health. To address this issue, the development of advanced photocatalytic materials capable of efficiently treating antibiotic-contaminated wastewater is imperative. In this investigation, we successfully synthesized nitrogen–phosphorus co-doped carbon dots (NPCDs) modified (001) TiO2/Ti3C2Tx composites via a series of uncomplicated hydrothermal reactions, ensuring visible light responsivity. Comprehensive characterization of the composite photocatalysts was conducted using XRD, FT-IR, N2 adsorption, SEM, TEM, XPS, UV-Vis DRS, and PL techniques. Subsequently, the photocatalytic performance was assessed through the degradation of tetracycline hydrochloride (TC) and ceftiofur sodium solutions under visible light irradiation. The optimized composites exhibited remarkable photocatalytic degradation efficiencies of 93.4% and 75.5% for TC and ceftiofur sodium, respectively, under visible light, following quasi-primary kinetic behavior. Reactive free radical capture experiments highlighted the predominant roles of ˙O2− and ˙OH species in the photocatalytic degradation process. Additionally, we proposed plausible mechanisms governing photocatalytic degradation based on the obtained results. The heightened photocatalytic reactivity arises from the efficient transfer of photogenerated electrons through the NPCDs → TiO2 →Ti3C2Tx pathway, a mechanism that effectively facilitates the separation and transfer of photogenerated charge carriers. [ABSTRACT FROM AUTHOR]

This work reported an Aux/BaTiO3 plasmonic photocatalyst with superior photocatalytic CO2 reduction performance under visible light irradiation compared to ordinary BaTiO3. This is mainly attributed to the introduction of plasmonic Au NPs, which improves the separation efficiency of photogenerated carriers and further enhances the photocatalytic CO2 reduction performance of the catalyst through the hot electrons generated by the LSPR effect. The photocatalytic conversion rates of CO2 to CO and CH4 by Au5/BaTiO3 reached 62.3 and 20.7 μmol g−1 h−1, respectively. [ABSTRACT FROM AUTHOR]

The development of clean and sustainable nitrogen-fixing methods has always attracted significant attention for decades. In this work, we investigated a strategy to enhance the N2 photo-fixation performance of titanium dioxide (TiO2) films by leveraging the synergistic effect between photon localization effects and iron (Fe) doping. Introducing Fe ions into TiO2 broadens its light absorption spectrum, making it extend into the visible light range, while improving charge separation capabilities. Our findings revealed that the photocatalytic ammonia generation of Fe-doped TiO2 (FT) catalysts, with a Fe3+ concentration of 6%, could reach up to 1.5 times that of pure TiO2. Besides, the photon localization effect of the SiO2 opal photonic crystals (SOPC) could enhance the light harvesting efficiency of the photocatalysts. By coupling the SOPC layer and nanocrystalline FT films, the N2 photo-fixation performance of FT/SOPC composite membranes was further promoted to 55.6 mmol g-1 h-1. This study offered a promising route for nitrogen fixation using solar energy. [ABSTRACT FROM AUTHOR]

NiO nanoparticles were synthesized and modified with Ni0 in the form of Ni/NiO blend and supported on a porous diatomite substrate, forming hybrid structures of NiO/D and Ni@NiO/D with enhanced photocatalytic performances. The obtained structures were applied for the effective oxidation of acephate pesticides under visible light. The obtained results demonstrated enhancement in the catalytic performance of Ni@NiO/D compared to NiO, Ni/NiO, and NiO/D structures. The full oxidation of AC (50 mg L−1) was determined after 40 min using Ni@NiO/D at doses of 0.5 g L−1. Moreover, the complete mineralization of AC molecules over Ni@NiO/D was detected after 70 min, considering the complete removal of TOC and the detection of essential inorganic anions (NO3− (7.6 × 10−5 mol L−1), SO42− (1.7 × 10−5 mol L−1), and PO43− (5.4 × 10−5 mol L−1)). The oxidation pathway was illustrated by considering the estimated intermediates and the detection of hydroxyl radicals as main oxidizing species. The toxicity of untreated AC solutions and degraded intermediates was analyzed by assessing their inhibitory effect on Vibrio fischeri. Samples that underwent partial oxidation during their initial examination exhibited a greater degree of toxicity (65.3% inhibition) compared to AC. Nevertheless, a sample subjected to an 80 minute treatment exhibited neglected toxicity (1.4% inhibition). The combination of the diatomite substrate and Ni0 doping enhanced the adsorption and photocatalytic properties of NiO. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs) have been studied for years as one of the most promising fluorescent nanomaterials. Herein, fluorescent CDs excited by visible light emitted red fluorescence with a quantum yield of 32.8% via a facile hydrothermal treatment. In addition to being applied in cell imaging, the as-prepared CDs were also utilized in the detection of ammonia and formaldehyde in aqueous solutions because of their pH-dependent properties, with a low limit of detection of 3.7 nM and 44 μM, respectively. Furthermore, we synthesized flexible and transparent fluorescence films by mixing the as-prepared CDs and PVB powder, which can be utilized to directly detect ammonia gas under visible light according to significant colour changes. Therefore, the as-prepared CDs would have more prominent and influential application in clinical diagnostics and environmental analysis. [ABSTRACT FROM AUTHOR]

The development of high-efficiency and low-cost photocatalysts for hydrogen production reactions is very important to solve energy problems. In this paper we study the photocatalytic H2 evolution activity of a CeO2/CoS2 heterojunction catalyst under visible light. Characterization studies such as XRD and XPS proved the successful synthesis of a CeO2/CoS2 catalyst. The composite catalyst with a CeO2 and CoS2 mass ratio of 1 : 20 had the best activity, and the hydrogen evolution rate reached 5172.20 μmol g−1 h−1. BET and UV-Vis DRS characterization showed that the introduction of CeO2 not only increased the specific surface area of the composite catalyst, but also improved the response of the photocatalyst to visible light. In addition, PL and electrochemical experiments showed that the electrons and holes of the CeO2/CoS2 catalyst could be quickly separated and transferred, thereby accelerating the kinetics of the hydrogen evolution reaction. This work provided an experimental basis for designing a composite photocatalyst with high stability and hydrogen production activity. [ABSTRACT FROM AUTHOR]

Based on the anion exchange strategy, a novel Bi2S3/BiOCl0.1Br0.9 S-scheme heterojunction was prepared via a facile one-step low-temperature water bath method for the first time. In this process, 2D Bi2S3 nanosheets were controllably grown on the surface of a 3D hollow BiOCl0.1Br0.9 solid solution. Under visible light irradiation, the as-prepared 3BS-BCB exhibited a remarkable photocatalytic degradation efficiency of 99.67% toward rhodamine B (Rh B) within 140 min, which is approximately 3.57 times higher than that of the BiOCl0.1Br0.9 solid solution alone. The enhanced photocatalytic performance is attributed to the formation of an interfacial electric field (IEF), which accelerated the separation rate of photoinduced electron–hole pairs and coupled the strong redox ability of both the semiconductors. Moreover, the photosensitive effect of Bi2S3 extended its light absorption range, increasing the yield of photogenerated charge carriers. Such thermodynamic and kinetic compatibility is the fundamental reason for the enhanced photocatalytic efficiency. This study provides new insights into the design of S-scheme heterojunction photocatalysts with visible light response and high redox ability based on wide-band gap semiconductors. [ABSTRACT FROM AUTHOR]

A novel Fe–RGO/TiO2/PTFE photocatalytic composite membrane was developed for the purification of MB wastewater. The properties of the prepared membranes were characterized using XRD, SEM, FT-IR spectroscopy, the BET method, and water contact angle, membrane flux, and BSA adsorption measurements. The photocatalytic properties of the surface-modified membranes were investigated in filtration experiments using MB as a representative organic contaminant. The results of the experiments showed that the Fe–RGO/TiO2 particles were securely loaded onto the surface of the PTFE membrane, demonstrating excellent chemical stability of the composite membrane. The incorporation of Fe3+ inhibited the agglomeration of TiO2 particles and enhanced the photocatalytic reaction rate. The introduction of RGO could broaden the photoresponsive range of TiO2, increase the specific surface area of the photocatalyst, introduce a large number of hydrophilic groups to enhance the hydrophilicity of the composite membrane, and subsequently increase the membrane flux. The MB wastewater was treated with the Fe–RGO/TiO2/PTFE composite membrane system for 3 h and the removal rate of MB reached 95.8% and 60.1% under UV and visible light, respectively. Reaction kinetic analysis indicated that the removal process of MB wastewater by Fe–RGO/TiO2/PTFE involves an adsorption–degradation–filtration synergy mechanism. [ABSTRACT FROM AUTHOR]

Spherical BiOI/UiO-66(Zr) composite materials were synthesized using a solvothermal method. The compositions, structures, and optical properties of the materials were characterized through X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, Brunauer–Emmett–Teller measurements, and UV-Vis spectroscopy. The experimental investigation involved the activation of persulfate (PMS) by BiOI/UiO-66(Zr) for the visible light degradation of Acid Orange II. The effects of the BiOI to UiO-66(Zr) mass ratio, BiOI/UiO-66(Zr) dosage, PMS concentration, Acid Orange II concentration, pH, and inorganic anion species on the degradation system were explored. BiOI/UiO-66(Zr) exhibited excellent visible light responsiveness. Under the optimal conditions (BiOI to UiO-66(Zr) mass ratio of 1 : 0.3, BiOI/UiO-66(Zr) dosage of 300 mg L−1, 0.3 mmol L−1 PMS, 100 mg L−1 Acid Orange II, 25 °C, and pH 7.0), the degradation efficiency reached 98.5%. While HCO3− and CO32− significantly influenced the reaction system, NO3−, Cl−, and SO42− had minimal impact. The reaction process followed a first-order kinetic model. Mechanistic analysis indicated that efficient transfer of holes and electrons between BiOI and UiO-66(Zr) occurred during the degradation, enhancing the separation efficiency of photo-generated electron–hole pairs. The ˙O2− and 1O2 generated in the reaction system played a crucial role in photocatalytic degradation of Acid Orange II, with ˙OH, SO4−˙, and h+ acting as auxiliary agents. The degradation process was a result of the synergistic action of various reactive radicals. Repetitive photocatalysis experiments demonstrated that the BiOI/UiO-66(Zr) composite exhibited excellent stability, with minimal reduction in degradation efficiency after four cycles. [ABSTRACT FROM AUTHOR]

A novel MOF-derived Mn2O3-decorated MoS2-graphene (MMG) composite was prepared via a facile hydrothermal method. The synthesized MMG composite was characterized through PXRD, FT-IR spectroscopy, DRS, TEM, FESEM, XPS and PL techniques. The prepared pure Mn2O3 exhibits a nano-chain-like agglomerated morphology with an average particle size of 50 nm distributed on the MoS2 and graphene layer as indicated by TEM images. DRS studies reveal a band gap of 1.22 eV for the MMG hybrid, demonstrating that the MMG hybrid can be used as a visible light–active photocatalyst. The study shows that the MMG-3 catalyst is excellent for the degradation of penicillin G under visible light with a rate constant (kapp) of 1.1 × 10−1 min. The photodegradation of PG by the MMG catalyst was found to be significantly faster than that by individual MSG or Mn2O3. The synergistic effect of MoS2 and graphene and a higher charge separation in the composite are major factors for a higher photocatalytic activity of the MMG catalyst. Moreover, the MMG catalyst exhibits good photostability, which ensures its potential applications in wastewater treatment and other energy applications. Finally, the photocatalytic mechanism of the MMG hybrid under visible light is presented after performing some radical scavenger tests. [ABSTRACT FROM AUTHOR]

Lignocellulose nanofibrils (LCNFs), as an emerging member of the green nanofibril family, have tremendous potential in improving the dispersibility, adsorption and photogenerated carrier separation efficiency of BiOBr because of the combination of the advantages of nanocellulose (NC) and nanolignins. Herein, sulfated lignocellulose nanofibrils (SLCNFs) were obtained from the poplar alkaline peroxide mechanical pulp (APMP) using a deep eutectic solvent (DES) and a mechanical defibrillation strategy, and flower-like BiOBr/SLCNF composites with oxygen vacancies were prepared by in situ synthesis. Due to the well-preserved lignin structure, abundant oxygen-containing functional groups, and the interconnected three-dimensional mesh structure in SLCNFs, the composites exhibited flower-like morphology, good dispersion and excellent adsorption performance after the introduction of SLCNFs. EPR analysis showed that the introduction of SLCNFs increased the number of oxygen vacancies in BiOBr, which improved the visible light absorption and reduced the recombination of photogenerated carriers. In addition, the photocatalytic activity improved with interfacial interaction between BiOBr and SLCNFs promoting the separation of electrons and holes. Therefore, BiOBr/SLCNF can effectively remove RhB in the dynamic continuous process of adsorption enrichment and photocatalytic oxidation. Under visible light, 99% of RhB was degraded within 30 min and 88.5% of tetracycline hydrochloride (TCH) was degraded within 60 min. Importantly, the main active species which removed RhB by BiOBr/SLCNF were ˙O2− and h+, and the BiOBr/SLCNF composites still have good stability and recyclability after 5 times of repeated use. Overall, the BiOBr/SLCNF composite photocatalyst has great potential for the purification of organic wastewater. [ABSTRACT FROM AUTHOR]

Pollution-related problems in the water environment caused by nuclear wastewater leakage has attracted widespread public attention. In this study, the strategy of treating waste with waste was adopted to prepare a tea waste-derived biochar/g-C3N4/MoS2 (BgM) Z-scheme composite for the photocatalytic reduction of U(VI) in water using thermal polymerization and hydrothermal methods. Among different proportions of BGMs, 10%BgM holds the highest removal efficiency of U(VI). Approximately all U(VI) was removed by 10%BgM under air atmosphere after 2 h of light irradiation (pH = 4.5, dosage is 0.5 g L−1). Furthermore, the removal efficiency of U(VI) by 10%BgM remained >80% after five cycles of tests, and it maintained a high selectivity in the presence of co-existing ions. Based on the quenching experiments and characterization analysis, photogenerated e− and ˙O2− play an important role in the reduction of U(VI). The enhancement of the photoreduction activity can be attributed to the acceleration of photogenerated electron transfer by the incorporation of tea waste biochar and the formation of a Z-type charge transfer mechanism, which improved the visible light absorption capacity. This study presents a promising material and approach for the effective treatment of uranium wastewater using photocatalysis. [ABSTRACT FROM AUTHOR]

The photocatalytic reduction of carbon dioxide into high value-added chemical feedstock is significant for mitigation of the energy crisis and the greenhouse effect. Metal–organic frameworks (MOFs) possess broad application prospects in photocatalytic CO2 conversion due to the ability to adjust the metal types in metal cluster nodes. Herein, the CO2 photocatalytic performance of trimetallic Fe0.02Ni0.10–Cox–PCN-250 (x = 0.05, 0.10, 0.15, 0.20 mol) was investigated by adjusting the content of Co. Notably, the photocatalytic yields of Fe0.02Ni0.10–Cox–PCN-250 (x = 0.05, 0.10, 0.15, 0.20 mol) were higher than those of bimetallic Fe0.02Ni0.10–PCN-250 and Fe0.02Co0.10–PCN-250 irradiated by visible light. The optimum yield of CO was obtained by trimetallic Fe0.02Ni0.10–Co0.15–PCN-250, up to 299 μmol g−1 h−1. The enhanced yield of CO might be ascribed to the high CO2 adsorption capacity and photogenerated electron transfer after addition of a suitable amount of the third ion, Co. This study provides new insights by designing trimetallic catalysts to increase the efficiency of photocatalytic CO2 reduction. [ABSTRACT FROM AUTHOR]

The photodegradation of propranolol (PRO) by BiOCl0.5I0.5/persulfate under visible light was comprehensively investigated. The results demonstrated a significant increase in the removal efficiency of PRO under visible light irradiation, achieved by the combination of BiOCl0.5I0.5 solid solution and persulfate (PS). The photocatalytic activity of the system was found to be enhanced with an increase in the pH value. Additionally, the addition of a certain amount of PS improved the degradation of PRO. The presence of typical water constituents, Cl− and NO3−, had a negligible impact on PRO removal. In contrast, the increasing concentration of humic acid (HA) exhibited apparent inhibition of PRO degradation. Furthermore, radical scavenging experiments revealed that the removal of PRO was primarily facilitated by active free species, including h+ and ˙O2−. The presence of characteristic peaks of ˙OH (peak ratio 1 : 2 : 2 : 1), 1O2 and ˙SO4− in the EPR spectrum indicates that these three radicals are also involved in the degradation process. Moreover, the BiOCl0.5I0.5/PS system demonstrated excellent photocatalytic activity, as well as favorable reusability and stability. This study offers new insights into the photocatalytic degradation of PRO, presenting a promising approach in this field. [ABSTRACT FROM AUTHOR]

Heterojunctions are of great importance for improving photocatalytic performance. Using simple solvothermal and solid reduction techniques, plasmon bismuth (Bi0) nanoflake-decorated BiFeO3 (BBFO) heterojunction photocatalysts with numerous oxygen vacancies (OVs) were created. The OVs not only improved photo-generated carrier separation, but also the sorption and activation of antibiotic compounds (tetracycline hydrochloride, TC). Furthermore, the surface plasmon resonance (SPR) effect of the Bi0 nanoflakes can boost visible light absorption and inhibit charge carrier recombination, resulting in an excellent ability for TC elimination under visible light illumination. The removal ratio of TC for BBFO is up to 99%, which is several times higher than that for pure BiFeO3. The obvious photothermal effect could further enhance the photocatalytic activity owing to an SPR effect and defect engineering. Trapping experiments indicate that the emergence of plentiful OVs, the participation of metal Bi0 nanoflakes, and the formation of heterojunctions can significantly promote photogenerated charge separation, thus improving photothermal-photocatalytic performance. This work combines thermal and chemical energies in solar energy conversion for efficient degradation of pollutants, which would bring new ideas to solve the problems of environmental pollution and energy shortage. [ABSTRACT FROM AUTHOR]

Tetrabromobisphenol A (TBBPA), a prevalent brominated flame retardant, poses significant environmental and health risks, necessitating its removal. In this study, WO3 with different structures was synthesized for TBBPA photodegradation under visible light using H2O2 and O2 as oxidants. The catalyst exhibited robust stability and reusability, rendering it suitable for practical applications. The crystalline structure and surface structure of WO3 controlled its catalytic activity towards TBBPA photodegradation. Monoclinic WO3 with the (022) plane was found to be the most active for ˙O2− active species generation from H2O2 and thus active for TBBPA degradation. Degradation product analysis showed that the catalyst was active not only for the removal of TBBPA, but also for the debromination of TBBPA. Nearly 100% debromination was achieved. [ABSTRACT FROM AUTHOR]

Three-dimensional rose-like ZnO (R-ZnO) is an appealing photocatalyst due to its remarkable properties, while it is also essential to boost its current visible light photocatalytic performance. In this study, R-ZnO was prepared by the hydrothermal method, and oxygen vacancies and Ag nanoparticles were introduced by calcining the ZnO precursor in an argon atmosphere and the photoreduction method, respectively, to improve the photocatalytic activity. The prepared Ag/Ar-ZnO exhibits a narrower bandgap of 2.79 eV, highly increased light absorption both in the ultraviolet and visible light regions, and improved charge separation and transfer efficiencies induced by the relatively higher number of oxygen vacancies and the localized surface plasmon resonance (LSPR) effect of the Ag nanoparticles. Therefore, Ag/Ar-ZnO displays a significantly enhanced visible light photocatalytic performance, with a methyl orange (MO) photodegradation rate constant (Kap) that is 2.41 and 3.59 times higher than those of Ag-ZnO and Ar-ZnO, respectively. This research offers an effective way to enhance the photodegradation performance of R-ZnO under visible light irradiation. [ABSTRACT FROM AUTHOR]

A fluorescent molecular switch (SP-OX-HBT), designed by fusing spiropyran with 2-(2-hydroxyphenyl)benzothiazole (HBT), exhibited red, orange and dark emission color switching among four states in the solution and solid states. The transformation from merocyanine (SP-OX-HBT) to ring-closed spiropyran (SP-HBT-C) or deprotonated ring-closed spiropyran (SP-HBT-CN) could be controlled by visible light or base stimuli, respectively, and these processes are verified by UV-vis spectra. The deprotonated merocyanine form (MC-N) was briefly involved in the basochromic process in solution but stable in the solid state. Besides the significant visible and fluorescent color variations, the single molecular switch has been further successfully applied to construct reversible multicolor displays and for anti-counterfeiting. [ABSTRACT FROM AUTHOR]

In this paper, a new visible-light harvesting photocatalyst denoted as g-C3N4/γ-Fe2O3/TiO2/Pd was successfully fabricated and fully characterized by different techniques including FT-IR, XPS, XRD, TEM, SEM, elemental mapping, VSM, DRS, and ICP analysis. The as-prepared catalyst was utilized as an efficient magnetically separable photocatalyst in the fluoride-free Hiyama and Suzuki–Miyaura cross-coupling reactions at room temperature under visible light irradiation. By using this approach good to excellent yields of biaryls were achieved from the reaction of various aryl iodides/bromides and even chlorides as highly challenging substrates, which are more available and cheaper than aryl iodides and bromides, with triethoxyphenylsilane or phenylboronic acid. The superior photocatalytic activity of g-C3N4/γ-Fe2O3/TiO2/Pd could be attributed to the synergistic catalytic effects of Pd nanoparticles and g-C3N4/γ-Fe2O3/TiO2. Utilizing a sustainable and safe light source, no need to use any additive or heat, using an eco-friendly solvent and long-term stability and magnetic recyclability of the catalyst for at least seven successive runs are the advantages that support the current protocol towards green chemistry. [ABSTRACT FROM AUTHOR]

In this paper, the sensitization photodegradation of single and mixed dyes by wide band gap boron nitride (BN, 3.94 eV) under visible light irradiation has been investigated for the first time. The obtained results show that the sensitization degradation of rhodamine B (RhB) most easily occurs (45.2%), followed by methylene blue (MB, 12.2%) and methyl orange (MO, 7.4%). This may occur because the photo-induced electron is the easiest to transfer from dyes to BN via hydrogen bonding (interaction between RhB and BN) and then π⋯π stacking (interaction between MB and BN). MO is an anion and BN has a negative surface, which may result in the sensitization photodegradation of MO being the worst among RhB, MB and MO. The sensitization photodegradation results of RhB–MB and RhB–MO by BN under visible light irradiation are very interesting. For the RhB–MB mixture, the photodegradation of RhB decreased to 9.2% from 45.2%, but the photodegradation of MB increased to 45.4% from 12.2%. This may occur because the MB moiety in the RhB–MB complex faces BN, and MB is less stable than RhB, leading to the increased photodegradation of MB. When RhB interacted with MO to form the RhB–MO complex, the photodegradation of RhB decreased to 2.6% from 45.2%, and the photodegradation of MO increased only to 10.7% from 7.4%. This may be due to the MO moiety in the RhB–MO complex facing BN and the transfer of the photo-induced electron from the negative MO to the negative surface of BN not being easy. This work can help facilitate a deeper understanding of the sensitization phenomena during wastewater treatment. [ABSTRACT FROM AUTHOR]

In this paper, copper-based oxide (CuO/Cu2O, Cu2O, Cu2O/Cu, and Cu) nano/micron particles were prepared in polyethylene glycol (PEG)-400 with copper acetate (Cu(CH3COO)2·H2O) as a raw material by a one-step thermal decomposition method. The effects of the reaction time on the valence state, composition, morphology and particle size of the products were investigated. The results show that PEG-400 acted as a modifier and reductant in the system, reducing the copper source from Cu(II) through Cu(I) to elemental Cu. Cu-Based nanocomposites with different valence states were formed at different time points. The photocatalytic activity of the products decreased with the increase of the particle size and the width of the band gap. The CuO/Cu2O composites exhibited as high as 97% (0.0485 g g−1) photocatalytic degradation of rhodamine B (RhB) in 5 minutes under visible light in the presence of H2O2. This simple and green method can be used to tune the composition of copper-based oxide nanocomposites with excellent performance and is suitable for scaling up. [ABSTRACT FROM AUTHOR]

In this paper, we reported, for the first time, the preparation of La2MnTiO6 double perovskite nanostructures using a simple sol–gel method in the presence of citric acid as the size controlling agent. The crystalline structure, morphology, and elemental composition of the prepared samples were characterized by XRD, TEM, FE-SEM, and EDX mapping analysis. Owing to superior electronic properties of the double perovskite, we used the prepared samples in the photocatalytic degradation of acid blue 113 (AB 113) under visible light irradiation. The photocatalytic degradation of AB 113 was nearly 72% after 120 min irradiation. Also, the effects of the photocatalyst amount and pH value of the dye solution were studied. Investigation on the photocatalytic degradation mechanism using various radical scavenging agents revealed that the photo-generated holes are the dominant oxidants for the degradation of AB 113. The reusability experiment showed that the prepared sample has good recyclability even for 6 reaction cycles. [ABSTRACT FROM AUTHOR]

A novel metal-free and environment-friendly approach for synthesizing biologically important moieties, benzothiazoles and benzimidazoles, under visible light irradiation using photocatalyst Eosin Y, ethanol:water as a green solvent and atmospheric air as an oxidant has been developed. Using an organic dye, Eosin Y, provided a mild and economical catalytic system to synthesize a series of benzothiazoles and benzimidazoles in good to excellent yields. Besides, the photocatalytic system does not require an additional oxidant, which is good for the environment. This method has several advantages, including the absence of metals, low cost, environmental friendliness, green solvent, non-toxicity, ease of handling, and renewable energy sources such as visible light. [ABSTRACT FROM AUTHOR]

A new cobalt(II) coordination polymer 'Cp-Co' has been designed and synthesized. The construction includes cobalt(II) as the central metal core along with 1,4-benzenedicarboxylic acid and the spacer 3,5-diamino-1,2,4-triazole obtained by a solvothermal method. The architecture of 'Cp-Co' was established using single X-ray crystallography and the topology of the coordination polymer. The 'Cp-Co' exhibited a periodic 3D framework. Furthermore, infrared spectroscopy (FT-IR), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and Brunauer–Emmett–Teller (BET) analysis further supported the structure of 'Cp-Co'. The prepared material was explored as a catalyst for the photocatalytic degradation of methyl green (MG) dye and displayed outstanding degradation efficiency under visible light radiation. The experimental design was explored towards optimization of the reaction variables, such as catalyst dose, MG dye concentration, etc. It was found that 10 mg of Cp-Co with 150 mg L−1 MG resulted in 99.77% photocatalytic efficiency within 60 min of visible light irradiation. The kinetic data was simulated using the Langmuir–Hinshelwood kinetic model and the value of the apparent rate constant (Kapp) was found to be 0.020 min−1, 0.024 min−1 and 0.029 min−1 for 50, 100 and 150 mg L−1 MG concentrations. The trapping experiments suggested the involvement of a superoxide anion radical (O2−˙) in the degradation of MG. [ABSTRACT FROM AUTHOR]