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Metal–organic frameworks (MOFs) have great potential for producing photoelectrocatalyzed hydrogen and degrading pollutants, owing to several factors such as high porosity and tunable semiconductor-like properties. Wide band gaps, which restrict their use to only UV light induced reactions, and low efficiencies for the separation of photogenerated charge carriers (electrons and holes) pose significant challenges to the widespread applications of MOFs. In this study, a hierarchical hollow Pt@H-UiO-66-NH2/CdS ternary catalyst was designed and synthesized. The immobilized CdS nanoparticles (NPs) in this catalyst endow the MOF H-UiO-66-NH2 with high visible light absorption ability and the Pt NPs serve as electron sinks to improve charge carrier separation. Furthermore, the hierarchical hollow structure of H-UiO-66-NH2 in the composite contributes to boosting light absorption and shortening the distance for charge transfer. As a proof of principle, Pt@H-UiO-66-NH2/CdS catalyzes methylene blue (MB) degradation with a high rate constant of 1.025 × 10−2 and hydrogen production with a rate of 12 810 μmol g−1 h−1, the latter of which is about 2.3, 11.7 and 173 times higher than those of Pt@UiO-66-NH2/CdS, H-UiO-66-NH2/CdS and Pt@H-UiO-66-NH2, respectively. [ABSTRACT FROM AUTHOR]

Highly efficient 2D/2D layered heterostructure of nickel oxide (NiO) and molybdenum sulphide (MoS2) has been fabricated for the photoelectrochemical (PEC) water splitting and degradation of Bromophenol Blue (BPB) under visible light. The XRD spectra confirm mixed characteristic peaks of MoS2 and NiO in the nanocomposite. SEM displays flower-like patterns of pure and composite material with the 2D nanosheets layer structure. The band gap reduction (2.25–1.72 eV) is due to the incorporation of NiO in MoS2 for visible light harvesting. TEM confirms the homogeneous distribution of 2D/2D nanosheets. The excellent interfacial coupling in strong 2D/2D interactions boost the electro and photocatalytic activities. 15.0% NiO showed excellent PEC activity toward OER with maximum photocurrent density of 1.57 mA cm−2, which influenced the overall water splitting at lower potential, ensuring visible photoresponse. The maximum photodegradation performance for highly toxic BPB was achieved by the photocatalyst, which contains 15.0 wt% NiO in NiO/MoS2 composite. It displays the highest conversion efficiency (∼87.0%) for BPB owing to exposed active sites via Mo–Ni–S linkages. Defects in NiO/MoS2 offer favorable reaction dynamics to PEC OER, which are helpful in tuning the band potentials. [ABSTRACT FROM AUTHOR]

Building Z-scheme heterojunction systems is a high-efficiency pathway to improve the utilization of visible light. Herein, CsxPW11M/g-C3N4 (M = Co, Fe) was successfully prepared by the simple grinding and calcination technology with a Z-scheme heterojunction structure. This Z-scheme heterojunction structure could significantly improve the separation and utilization efficiency of photogenerated carriers while enhancing the redox capacity and photocatalytic activity. The energy band structure of Keggin-type polymers was optimized by modulating the coordination metal. The prepared composites have specific high photocatalytic properties and good reusability. The photocatalytic degradation activity of the prepared CsxPW11M (M = Co, Fe) modified 2D g-C3N4 materials was investigated using two different types of pollutants. Currently, when the loading capacity of CsxPW11M in the CsxPW11M/g-C3N4 sample reached 3 wt%, the photocatalyst of this composite material showed the best photocatalytic degradation performance. Meanwhile, the active species of the response were explored through free radical trapping experiments and ESR characterization, indicating that h+,˙O2 and ˙1O2 played a key role. The suitable band structure and the correct charge analysis, as well as the investigation of the transfer mechanism, provided new ideas for the construction of a Z-scheme heterojunction structure using Keggin-type transition metal-substituted heteropolymers and 2D g-C3N4. It improves the performance of conventional catalysts. [ABSTRACT FROM AUTHOR]

In the rapid growth of perovskite solar cells, there are still specific issues regarding the extensive absorption of incident photons. Double-layered methyl ammonium (MA)-free perovskite solar cells (PSC) have been proposed to sort out these issues. The material absorber in solar cells based on MA-free and cesium-based perovskite, i.e., Cs2BiAgI6, is a critical parameter because of its non-volatile nature as well as its band gap of 1.6 eV being helpful in a broader visible absorption spectrum than the conventional CH3NH3PbI3 material. Moreover, the quantum efficiency (QE) and power conversion efficiency (PCE) in a configuration with MXene + TiO2 as the electron transport layer (ETL) in the PSC can make improvements over a more extensive range. The results of the current modeling of numerical simulations are used to investigate the exclusive optoelectrical outputs of the PSC. Furthermore, we use a novel approach of an ETL of MXene + TiO2 in a PSC, which will lower the manufacturing cost and defectiveness. The present work compares different ETLs to attain the best PCE using Cs2BiAgI6 as a perovskite absorber layer (PAL). The results are exciting as the highest open circuit voltage (VOC) of 1.48 V, high short current density (JSC) of 22.8 mA cm-2, with a high fill factor (FF) of nearly 84.6% in the double-layered PSC offer a high power conversion efficiency (PCE) of more than 28%. The designed outputs will be efficient for the convenient fabrication of the PSC. [ABSTRACT FROM AUTHOR]

We employed a solvothermal and thermal pyrolysis approach to prepare a heterojunction of oxide perovskite (Bi2MoO6) dispersed on polymeric carbon nitride (PCN) sheets. The introduction of Bi2MoO6 particles onto the PCN sheets improved the light absorption characteristics of the Bi2MoO6/PCN heterojunction. The as synthesized Bi2MoO6/PCN heterojunction exhibited a larger surface area of 24 m² g-1, compared to the individual Bi2MoO6 (18 m² g-1) and PCN (7 m² g-1), respectively. This enhanced surface area provided newer catalytic sites for the heterojunction. The resulting heterojunction was employed as a photocatalyst for the reduction of a series of toxic mono, di, and tri-nitrophenols, namely 2-nitrophenol, 3-nitrophenol, 4-nitrophenol, 2,4-dinitrophenol, and 2,4,6-trinitrophenol, into industrially important amino phenols. By utilizing visible light irradiation and NaBH4 as a reducing agent, the Bi2MoO6/PCN photocatalyst demonstrated accelerated reduction kinetics compared to the individual catalysts. This enhanced performance was attributed to the larger surface area and suppressed charge carrier recombination of the Bi2MoO6/PCN heterojunction, which facilitated efficient photoreduction. Overall, this study sheds light on the promising application of oxide perovskite/PCN heterojunction systems in photocatalytic reduction reactions, offering a viable solution for mitigating emerging pollutants. [ABSTRACT FROM AUTHOR]

Molecularly imprinted Ni and F co-doped TiO2 nanoparticles were synthesized via the sol–gel method. The nanoparticles displayed high photocatalytic activity under both sunlight and artificial visible light for degradation of bisoprolol. Characterization of the nanoparticles was carried out using XRD, FE-SEM, TEM, FT-IR, DRS, EDX and BET-BJH. The effects of different operational variables on the photocatalytic activity were optimized using the response surface methodology (RSM). The optimal experimental conditions for achieving the highest photocatalytic efficiency (72.5% by a desirability function value of 1.0) are as follows: pH = 5.9, photocatalyst mass = 83.42 mg, bisoprolol concentration = 16.2 mg L−1, and irradiation time = 137 min. The selectivity of the photocatalyst was investigated against pantoprazole. The excellent photocatalytic activity is attributed to the doping of Ni and F dopants into the TiO2 structure. The investigation of the mechanism of the photocatalytic reaction revealed that the main active species involved in the degradation of bisoprolol are OH˙ radicals. [ABSTRACT FROM AUTHOR]

Antibacterial RBS@Cu:ZnO nanoparticles (NPs) were prepared by decorating Cu-doped ZnO NPs with Roussin's black salt (RBS), a nitric oxide (NO) precursor. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) tests indicated that the RBS@Cu:ZnO NPs were particulate matter with crystal morphology and nanoscaled sizes. X-ray diffraction (XRD) patterns revealed the wurtzite crystal structure of the NPs. Under irradiation of 543 nm laser, the RBS@Cu:ZnO NPs released NO in a controllable manner due to the decomposition of RBS. Cu-doped ZnO with a Cu/Zn molar ratio of 5% showed antibacterial activity in response to ultraviolet and visible light by photocatalysis. The doping of Cu enhanced the visible light absorption of ZnO by reducing its band gap. The RBS@Cu:ZnO NPs exhibited high antibacterial activity originating from the synergistic bacterial inhibitory effects of Cu-doped ZnO and released NO under visible laser irradiation. More importantly, the antibacterial activity could be controlled by adjusting the power output of laser irradiation. The RBS@Cu:ZnO NPs are promising antibacterial agents with potential applications in biomedicine and pharmaceutics. [ABSTRACT FROM AUTHOR]

(001)-TiO2/BiOI photocatalysts with microsphere morphology were synthesized by a solvothermal method. The (001)-TiO2/BiOI demonstrated highest photocatalytic performance for the RhB degradation rate of 0.049 min−1 under visible light, which is 5 and 7 times that of (001)-TiO2 and BiOI, respectively. The increased photocatalytic efficiency is due to the construction of heterojunctions, which promote the transportation of photo-generated carriers. The good photochemical stability of the prepared photocatalysts was demonstrated by cycling experiments. The radical quenching experiments show that ˙O2− and ˙OH are the principal active species in the photocatalytic reaction mechanism. Finally, a possible mechanism of p–n heterojunctions in the photocatalytic reaction process was proposed. [ABSTRACT FROM AUTHOR]

Photocatalytic degradation is considered to be a promising approach for treating water contamination caused by industrialization. Hence, an eco-friendly photocatalyst with high efficiency is needed. Bismuth oxychloride (BiOCl) and Zr-doped BiOCl (ZBCl) with enhanced visible light-induced photocatalytic activities were prepared through a simple co-precipitation method at ambient conditions. The synthesized materials were characterized using XRD, FT-IR, Raman, UV-Vis DRS, PL, TEM, HRTEM, and BET analysis. Photocatalytic studies showed that ZBCl possesses higher photocatalytic activity for the degradation of rhodamine B under visible light irradiation in comparison to BiOCl. Among the synthesized materials, the 1% ZBCl exhibited the highest photocatalytic efficiency. The 1% ZBCl was able to degrade 97.7% of RhB dye within 60 min. Additionally, the linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) studies showed enhanced response under visible light irradiation in comparison to dark conditions which is caused by a decrease in electron transfer resistance and an increase in photocurrent. This research suggests that ZBCl can be used successfully as a photocatalyst and as a photoelectrode material due to its enhanced photocatalytic and photoelectrochemical response. [ABSTRACT FROM AUTHOR]

Element doping is an effective approach to modify the electronic structure of semiconductors and improve the photocatalytic activity. Herein, we designed a process for the oxygen doping of lamellar ZnIn2S4 (O-doped ZIS) nanosheets that were coated on layered g-C3N4 (CN) to form a g-C3N4/O-doped ZnIn2S4 (CN/O-doped ZIS) heterojunction to improve the charge separation efficiency, thereby boosting the photocatalytic performance of CN/O-doped ZIS. The optimized 20% CN/O-doped ZIS showed high photocatalytic performance (RhB, 97% in 20 min) under visible light, which is 19.6 and 2.5 times higher than that of CN and O-doped ZIS photocatalysts, respectively. In the investigations on the band structure, trapping experiments, and ESR tests, the photocatalytic mechanism of RhB degradation by the CN/O-doped ZIS composite was proposed. The photocatalytic performance was effectively promoted via oxygen doping and coupling with CN, which opens new insight into a highly efficient photocatalytic system. [ABSTRACT FROM AUTHOR]

α-Fe2O3/Bi2O3 nanocomposites with a p–n heterojunction were synthesized via an anodization strategy and the hydrothermal method for photocatalytic applications. By changing the hydrothermal treatment time, Bi2O3 nanosheets were deposited on the surface of α-Fe2O3 nanotube arrays (NTAs). The morphologies and photochemical performance of the as-prepared α-Fe2O3/Bi2O3 nanocomposites were investigated in detail. The presence of Bi2O3 nanosheets resulted in an obvious red-shift in the UV-Vis diffuse reflectance spectrum, indicating that the α-Fe2O3/Bi2O3 nanocomposites had an expanded visible light photo-response range. The α-Fe2O3/Bi2O3 nanocomposites displayed excellent photocatalytic activity, stability and recyclability toward the decomposition of methylene blue under visible light illumination. The photocurrent and electrochemical impedance spectra also testified efficient electron transport and charge separation in the α-Fe2O3/Bi2O3 nanocomposites. The enhanced photocatalytic performance can be ascribed to a high light harvesting ability, fast separation of photogenerated electron–hole pairs and the presence of an efficient interfacial electric field from the p–n heterojunction. The photogenerated holes and superoxide radicals played crucial roles in the photocatalytic process. The photocatalytic mechanism was discussed. [ABSTRACT FROM AUTHOR]

Solar-driven photocatalytic hydrogen generation via splitting water requires an efficient visible light active photocatalyst. In this work, Ni cocatalysts on a TiO2 composite photocatalyst with different graphene oxide (GO) contents were prepared using a hydrothermal method and characterized by TEM, XRD, UV-vis, Raman and PL spectra. The results show that the synthesized TiO2/GO/Ni nanosheet composites have a large specific surface area and can provide a large number of active sites for a photocatalytic hydrogen production reaction. GO can broaden the optical absorption range of TiO2 and absorb more visible light, thus stimulating more photogenerated electron–hole pairs. At the same time, GO can collect electrons and promote the separation of photogenerated electron–hole pairs. Ni, as a cocatalyst, can be used as an active site for hydrogen ion adsorption, which is conducive to promoting the migration of photogenerated electrons in the system and prolonging the life of photogenerated electrons and holes, thus ensuring the high efficiency of the photocatalytic reaction. [ABSTRACT FROM AUTHOR]

This work involved the in situ chemical polymerization of aniline at ambient temperature using a simple hydrothermal method to synthesize a novel ternary photocatalyst for wastewater treatment. The Z-scheme heterojunction features of this ternary nanocomposite (20 wt%-g-C3N4/0.5 wt%-PANI/α-MnO2) led to exceptional photocatalytic activity. In comparison to the pure nanomaterials g-C3N4 (15.5 m2 g−1) and α-MnO2 (18.5 m2 g−1), the surface area of the catalyst dramatically increased (40.5 m2 g−1) after being modified by PANI. Tetracycline hydrochloride (TCH) photodegradation was examined using pure g-C3N4 and α-MnO2, g-C3N4/α-MnO2 binary nanocomposite (with varying weight% of g-C3N4), and ternary nanocomposite (with varying weight% of PANI). After one hour, TCH (50 mg L−1) was degraded by a maximum of 96% with the ternary nanocomposite, which is much more than those of 20-g-C3N4/α-MnO2 (75%), g-C3N4 (35%) and α-MnO2 (20%). Even after five consecutive cycles, the modified ternary photocatalyst continued to function well and sustained almost 86% of its degrading efficiency. The large surface area and quenching of photoluminescence, which result in efficient separation of electron/hole pairs and consequent reduction in the rate of recombination of charge carriers, are the main causes of the ternary catalyst's strong photocatalytic activity. This study offers a method for enhancing photocatalytic activity using conductive polymers. [ABSTRACT FROM AUTHOR]

For the first time, the synthesis of the Cu2OQDs@MOF-801 nanocomposite using a simple and low cost route is reported. MOF-801 was chosen as the main matrix owing to its water stability, chemical stability, high surface area, suitable pore size, and biocompatibility. Cu2O QDs were well confined inside the MOF-801 as template and main matrix via the double solvents method (DSM) combined with an in situ reduction route (ISRR). The characterization of the MOF-801 and Cu2OQDs@MOF-801 nanocomposite was performed by PXRD, FT-IR, EDX, XPS, N2 adsorption–desorption isotherm, TEM, TGA, DRS, PL, EIS, and Mott–Schottky measurements. The band gap of Cu2OQDs@MOF-801 is smaller than that of MOF-801 and larger compared to bulk Cu2O due to the quantum confinement effect. The enhancement in the Cu2OQDs@MOF-801 photocatalytic activity can be attributed to rapid charge transfer, efficient separation of photoinduced charge carriers, and shortening of the distance for electron and hole transfer. [ABSTRACT FROM AUTHOR]

The low electron–hole separation in the photoanode generally restricts the visible light response of photocatalytic fuel cell (PFCs). In this study, 5% NH2-MIL-125/g-C3N4/Bi2O3/Ti photoanode was synthesized and assembled with a PFC with Cu cathode to degrade rhodamine B and generate electricity. With visible light irritation, the maximum photocurrent density, maximum power density, and degradation rate of the PFC were 0.59 mA cm−2, 29.88 μW cm−2, and 97.48% (1 h), respectively. The major active species in the PFC were h+, ˙O2−, and ˙OH. The good performance of the PFC was ascribed to the formation of a double Z-type heterojunction in the 5% NH2-MIL-125/g-C3N4/Bi2O3/Ti photoanode so that the photoelectrons of NH2-MIL-125 and Bi2O3 directly combine with the photoholes of g-C3N4, making the photoholes of NH2-MIL-125 and Bi2O3 and the photoelectrons of g-C3N4 directly or indirectly involved in the RhB degradation process and generating electricity. Thus, the separation rate of the e−–h+ pairs in the photoanode and the capability of the PFC are greatly improved. [ABSTRACT FROM AUTHOR]

In this study, a Cu2O/g-C3N4 nanocomposite was prepared through in situ growth of Cu2O nanoparticles on g-C3N4 nanosheets. Subsequently, the antibacterial activities of Cu2O, g-C3N4 and Cu2O/g-C3N4 composites against Staphylococcus aureus and Pseudomonas aeruginosa were studied, respectively. The results show that the minimum bacteriostatic concentration of the composite is significantly smaller than that of Cu2O and g-C3N4 alone, and it also has better long-term bacteriostatic effect. The bacteriostatic effect of the prepared Cu2O/g-C3N4 nanocomposites is further enhanced by visible light irradiation. The first-principles calculation based on density functional theory (DFT) was used to obtain the work function of the composite materials. The Cu2O/g-C3N4 composite has a work function that is significantly lower than that of Cu2O and g-C3N4. The lower work function is beneficial to the separation of electrons and holes and the formation of reactive oxygen species (ROS) on the surface of the material, further reducing photocorrosion. This also explains the reason why the composite material has high bacteriostatic efficiency and better bacteriostatic effect. In addition, the calculation of the differential charge shows that the Cu atom near the heterojunction interface has a strong positive charge, which makes it more difficult to cause redox reactions and enhances the long-acting effect of the bacteriostatic agent. Therefore, based on our experimental and theoretical calculation results, the Cu2O/g-C3N4 composite has a broad application prospect in the field of photocatalytic bacteriostasis. [ABSTRACT FROM AUTHOR]

ZnIn2S4 is considered one of most promising green catalysts for visible light driven photocatalytic H2 generation, but it suffers from relatively low photocatalytic performance. Here, we for the first time report the design and preparation of an efficient ZnIn2S4-based catalyst using porous ZnWO4 as cocatalyst (denoted ZIS/PZW). ZIS/PZW consists of flower-like microspheres composed of ZnIn2S4 nanosheets embedded with porous ZnWO4 nanoflakelets. The as-synthesized ZIS/PZW showed excellent photocatalytic performance for H2 generation with an optimal hydrogen production rate of 8.86 mmol g−1 h−1. Further investigation revealed that the porous ZnWO4 cocatalyst could lead to the formation of dense contact sites with ZnIn2S4 nanosheets, thus benefiting electron migration. The hydrogen generation rate was found to be 2.15 times higher than that when solid ZnWO4 nanoparticles acted as cocatalyst. Our work highlights the importance of finely designing cocatalysts and provides a new route for the further development of high-efficiency ZnIn2S4-based photocatalysts for H2 generation. [ABSTRACT FROM AUTHOR]

Due to their carcinogenic, mutagenic and poisonous nature, industrial wastes such as metals, dyes, polycyclic aromatic hydrocarbons, surfactants and pharmaceutical waste have become a major worldwide issue for human health. In this context, we are reporting the synthesis, characterization and application of copper-immobilized nanocomposites NiAlFeO4@Cu for catalytic reduction of hazardous and carcinogenic nitrophenols and photocatalytic degradation of different dyes (rhodamine B (RhB), methyl orange (MO) and methylene blue (MB)), individually as well as their mixture under visible light irradiation. Magnetically separable mesoporous composites of NiAlFeO4 and copper nanoparticles in the molar ratios of 2 : 1 (NAFO2@Cu), 5 : 1 (NAFO5@Cu) and 10 : 1 (NAFO10@Cu) were prepared through a simple reduction method with pure water as the solvent. The structural, morphological and physicochemical features of the prepared nanocatalysts were examined using PXRD, FE-SEM, PL, DRS, VSM and BET. The nanocomposites were found to be very porous and spherical with an average crystallite size between 4 and 8 nm. Magnetic measurements were carried out using a vibrating sample magnetometer, which reveal the ferromagnetic nature of our samples, making them magnetically separable. A UV/Vis study was used to analyse the reduction of nitrophenols by employing sodium borohydride as a reducing agent. Furthermore, the band gap energy values of the nanocomposites were found to be in the visible range (1.63–1.66 eV) making them suitable for photocatalysis. Rhodamine B was used as a model dye pollutant for estimation of the photocatalytic deterioration of the synthesized nanocatalysts. Among all the prepared nanocomposites, NAFO2@Cu exhibited the highest catalytic efficiency for the reduction of nitrophenols, while the maximum degradation efficiency was shown by NAFO10@Cu for the photodegradation of different dyes individually as well as in their ternary solution. [ABSTRACT FROM AUTHOR]

In this work, 2-aminobenthiol (ABT) small molecules were doped with g-C3N4/WO3via calcination to improve the visible light catalytic ability. Characterization methods such as SEM, TEM, and XPS were applied to explore the properties of the materials. A characterization study using UV diffuse reflection spectroscopy confirmed that the absorption capacity of 1 wt% ABT/CN in the visible region enhanced significantly after doping the 2-ABT molecule. TC (tetracycline) was used as the target pollutant to study the catalyst. The results showed that compared with g-C3N4, WO3, 1 wt% ABT-g-C3N4, and g-C3N4/WO3 materials, the 1 wt% ABT-CN/WO3 catalyst showed a more robust photocatalytic performance in the degradation of TC under visible light irradiation. The degradation rate of TC is 87.78% within 40 min. The composition of free radicals in the system and the role of ABT in the reaction process were analyzed, and the possible degradation mechanism was proposed. [ABSTRACT FROM AUTHOR]

Rhodamine B (RhB) is a carcinogenic cationic dye with strong stability and fluidity in water. For this purpose, carbon (C) modified TiO2 pillared illite/smectite (Ti(I/S)) composites (C-Ti(I/S)) were successfully synthesized to degrade RhB under visible light irradiation. Due to the existence of carbon nanomaterials, C-Ti(I/S) composites have a larger specific surface area and stronger electron hole separation ability than Ti(I/S) composites. The results showed that C-Ti(I/S) composites exhibited good photocatalytic activity for RhB degradation. After 120 min, about 80% of RhB was degraded by the C-Ti(I/S)-3 composite, which was much higher than that of C (40%) or Ti(I/S) (60%). In addition, the C-Ti(I/S)-3 composite also had good photocatalytic stability. In this photocatalytic system involving the C-Ti(I/S)-3 composite, the oxidation of RhB mainly involved h+ and ˙O2−. [ABSTRACT FROM AUTHOR]

An efficient ternary Ag/BiOBr/rGO nanoflower composite was prepared by applying in situ precipitation and reduction process. The rGO nanosheets and Ag nanoparticles were modified on three-dimensional BiOBr nanoflowers. The structure, morphology, photoelectrochemical properties, etc., of Ag/BiOBr/rGO-4 were characterized and explored. The photocatalytic activity of Ag/BiOBr/rGO was assessed for the degradation of HCHO and RhB. Ag/BiOBr/rGO-4 showed remarkably improved photocatalytic activity than BiOBr and BiOBr/rGO in the degradation of HCHO and RhB under visible light irradiation. The Ag/BiOBr/rGO-4 composite can degrade 69% gaseous HCHO (0.16 mg L−1) in 40 min (λ > 400 nm). The Ag/BiOBr/rGO-4 also has the highest photodegradation performance of RhB, with a 60 minutes degradation rate of 94%. The improved catalytic performance of the Ag/BiOBr/rGO is attributed to the following reasons: (1) rGO and Ag nanoparticles effectively improve the visible light absorption and utilization of BiOBr; (2) the construction of a Schottky junction between Ag nanoparticles and other components promotes charge flow and improves the separation of photo-generated carriers; (3) a three-dimensional nano-flower structure makes each component have good interface contact and fast carrier transfer ability and exposes more catalytic active sites. Furthermore, free-radical capture and ESR display that ˙O2− and ˙OH play major roles. The degradation process of the RhB is further investigated by LC-MS. The Ag/BiOBr/rGO composite reported in this research has great potential for environmental purification. [ABSTRACT FROM AUTHOR]

Constructing a heterojunction photocatalyst composed of two important two-dimensional (2D) materials, i.e., g-C3N4 and MoS2, to make full use of the unique advantages of each component has very important theoretical and demonstrative significance. Although it is possible to achieve enhanced visible light absorption and increased active sites in such a system, the practical difficulties stem from the loose interfacial coupling between the two and the formed type I heterostructure by specific energy level positions, which are both unfavorable for suppressing the recombination of photogenerated carriers. By creating N vacancies on g-C3N4 flakes and then inducing S atoms to enter the nitrogen vacancies to form Mo–S–C bonds, we prepared a tightly coupled heterojunction with strong electronic interfacial interaction. Not only that, MoS2 loaded onto g-C3N4 nanosheets exhibited a mixed-phase structure, in which the semiconducting (2H-MoS2) and metallic (1T-MoS2) phases act as good photosensitizers and electron acceptors, respectively. Due to the close contact and the synergistic effect of the MoS2 mixed phase, the currently designed unique heterostructure photocatalyst has greatly improved catalytic performance under visible light, which may provide new ideas for the hierarchical structure design of photocatalysts. [ABSTRACT FROM AUTHOR]

In this work, a novel flower-shaped NV-g-C3N5@VS2 heterojunction was prepared by hydrothermal in situ synthesis using NV-g-C3N5 as the matrix and thioacetamide as the precursor. The prepared heterojunction showed a flower-like and layered structure, which widened the visible light absorption range and facilitated the usage of visible light. Under visible light irradiation, the NV-g-C3N5@VS2 heterojunction exhibited excellent photoelectrocatalytic nitrogen reduction activity with an ammonia yield of 49.26 μg h−1 mg−1 in an electrolyte solution saturated with N2. Moreover, the NV-g-C3N5@VS2 heterojunction achieved outstanding photocatalytic degradation activity. The photocatalytic degradation rate of Rhodamine (RhB) reached 95% in 35 min under visible light irradiation. More importantly, the catalyst displayed good reusability and stability after four cycling runs for the photodegradation of MB. The prepared catalyst showed excellent photocatalytic universality and was also applied to efficiently degrade organic pollutants such as methyl orange (MO) and methylene blue (MB). Therefore, solar light-driven photocatalytic and photoelectrocatalytic applications based on the NV-g-C3N5@VS2 heterojunction are expected to pave a new way for fertilizers, energy utilization, and environmental remediation. [ABSTRACT FROM AUTHOR]

Keratin, a biological polymer with high sulfur content, is the main component of hair, feathers and wool. Human hair is the cheapest natural source of keratin. In this study, an optimized and very effective reduction reaction method was used to obtain keratin from human hair. During this process, the disulfide bridge of keratin was reduced in the presence of sodium sulfide to form free sulfhydryl (thiols) that would act as a strong nucleophile. The results of FTIR spectroscopy, Tricine-SDS-PAGE and MALDI-TOF/MS verified the successful extraction of the reduced human hair keratin. A well-interconnected structure with three-dimensional (3D) scaffolds was prepared using keratin and methacrylated gelatin (GelMA), KeratinGel, for tissue engineering and other biomedical applications. KeratinGel hydrogels were in situ prepared via Michael addition reaction and visible light crosslinking. Two complementary crosslinking reactions were combined to enhance the network structure and provide ductility. With the targeted two-step method, the reactivity of vinyl groups of GelMA to photocrosslinking and thiol groups in keratin to the Michael addition reaction was exploited. Rheological monitoring of the Michael addition reaction was performed for KeratinGel hydrogels in a basic reaction environment at pH 7.4 with a constant concentration of GelMA (10% w/v) and different amounts of reduced human hair keratin (5, 7.5 and 10% w/v) at room temperature. The physical properties, swelling and degradation rates of KeratinGel hydrogels were determined to understand their suitability for tissue regeneration. We finalize that KeratinGel hydrogels would be better in minimally invasive surgeries, soft tissue engineering, especially with in situ gelling features, and favourable for the preparation of complex shapes and applications. [ABSTRACT FROM AUTHOR]

Developing multifunctional materials for 2-naphthol (2-NAP) monitoring is in urgent demand since 2-NAP not only brings us convenience but also causes serious environmental and health issues. Herein, we report a novel β-cyclodextrin (β-CD)-based molecular-responsive photonic hydrogel chemosensor composed of a poly(N-isopropylacrylamide-co-maleic anhydride-β-cyclodextrin) (PNACD) hydrogel with embedded superparamagnetic Fe3O4 colloidal particle chains, for highly sensitive and visual detection of 2-NAP in aqueous solution. The Fe3O4 particle chains in the polymer matrix could strongly diffract visible light and transmit a 2-NAP concentration signal to the color change of the gel by changing the gel volume and lattice spacing of Fe3O4 particles. The rich β-CD groups attached to the polymer networks could specifically recognize and bind to 2-NAP by forming stable β-CD/2-NAP inclusion complexes. This specific molecular recognition expanded the gel, increased the particle spacing, and thus redshifted the reflection wavelengths of the gel and indicated the color changes of the gel. This photonic hydrogel exhibited remarkable thermo- and pH-dependent responsiveness to 2-NAP, a wider linear detection range of 0.01–500 μM and a comparatively lower detection concentration of 0.01 μM compared with the conventional instrument-based methods. Besides, it also demonstrated excellent regenerability and was applicable to monitor 2-NAP in a simulated contaminated river water sample. Such a multifunctional hydrogel with high sensitivity and selectivity toward 2-NAP as well as excellent recyclability holds great potential in sensitive, precise and naked-eye detection of aromatic pollutants in contaminated water bodies. [ABSTRACT FROM AUTHOR]

In this work, we fabricated peculiar and highly cogent iron-doped graphitic carbon nitride (Fe@g-C3N4) nanocatalysts with varying ratios of g-C3N4 nanosheets to Fe-dopant in 1 : 1, 1 : 3, and 1 : 5, respectively. Numerous physicochemical techniques, including high-resolution transmission electron microscopy (HRTEM), Fourier transform infrared (FTIR), powder X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were used to validate the as-synthesized catalysts to explain their morphology and chemical structure. In addition, it was revealed that Fe metal ions were well disseminated with no alteration in the layered stacking structures of the g-C3N4 nanosheet and/or might interact with N atoms of the graphitic plane, forming intercalation compounds, thereupon influencing the energy band structure, augmenting visible light absorption, and electron–hole rupture rate. Under visible light (12 W) conditions, Fe@g-C3N4 (1 : 1) has shown superior performance for selective Baeyer–Villiger oxidation reaction, giving 100% cyclohexanone conversion and an admirable product selectivity of 2-oxepanone, i.e., 99.85%. Besides, the main advantages of the present catalyst include its excellent reusability up to five repeated cycles with no significant loss of activity. [ABSTRACT FROM AUTHOR]

To enhance charge transfer driving force and accomplish the high separation efficiency of photo-generated electrons and holes, a well-designed hierarchical BixOyIz nanoflowers with oxygen defect was obtained by regulating the calcination temperature of BiOI. The photoluminescence (PL) and electron paramagnetic resonance (EPR) measurements demonstrated that the concentrations of oxygen vacancies in BixOyIz changed with temperature. Benefiting from the strong attraction effect to electrons and the stronger oxidation capability, the oxygen-deficient Bi4O5I2 exhibited prominent visible light photocatalytic degradation performance towards antibiotic tetracycline (TC) and bisphenol A (BPA). The removal rates for TC and BPA could reach 100% within 10 min and 30 min, which are 10.13 times and 3.06 times than that of BiOI, respectively. This work provides a facile method for the synthesis of bismuth-rich materials and offers potential directions for the efficient degradation of antibiotics. [ABSTRACT FROM AUTHOR]

In order to synthesize α-Fe2O3 with improved surface conductivity for photo-Fenton catalysts, polyaniline (PANI)/α-Fe2O3 heterojunction composite catalysts (FP) were prepared using a simple non-in situ polymerization method, in which the aniline monomer is mixed with porous rod-like α-Fe2O3 obtained from rod-like β-FeOOH precursors. The effects of annealing temperatures on α-Fe2O3 and the molar ratio of the aniline monomer-to-α-Fe2O3 on FP were investigated by the removal of methylene blue (MB) under visible light Fenton conditions. The results showed that α-Fe2O3 annealed at 500 °C (F(T2)) exhibits the highest removal activity of MB among the α-Fe2O3 series, and when the molar ratio of the aniline monomer-to-F(T2) is 2 : 1, the sample (FP-3) removed 99% of MB within 20 min, which demonstrated that the visible light irradiation could promote the removal of MB by PANI/α-Fe2O3. The enhanced MB removal activity was attributed to the introduction of PANI into α-Fe2O3 constructing type-II heterojunctions, improving the surface conductivity and photogenerating the e−–h+ separation efficiency of α-Fe2O3 under photo-Fenton conditions, in which the cycling between Fe(II) and Fe(III) was accelerated by visible light in the FP-3 system. The hydroxyl radical (˙OH) and the cavity radical (h+) are the main reactive species in the photo-Fenton experiment as demonstrated using free radical quenching experiments and electron spin resonance tests. In addition, the FP-3 composite catalyst showed relatively good cycling performance. [ABSTRACT FROM AUTHOR]

Graphitic carbon nitride (CN) is considered to be a promising metal-free photocatalyst, but the charge carrier separation and rapid complexation of electrons and holes are difficult to modulate for effective and comprehensive photodegradation of TC. In this work, a MoS2 QD decorated sea-urchin carbon nitride nanohybrid was prepared via a water bath method. In comparison to the 85.6% degradation efficiency of sole sea-urchin carbon nitride (SUCN), the optimized 5% MoS2 QDs/SUCN (5%MSUCN) demonstrated a removal efficiency of 96.0% towards aqueous tetracycline (TC) under visible light. Such an outstanding photoactivity was mainly attributed to the interfacial synergistic effect of MoS2 QDs and SUCN, in which the outstanding charge extraction ability and quick surface kinetics of MoS2 QDs were primarily accountable for the subsequent deep photodegradation behavior of 5%MSUCN. A series of factors that may affect photoactivity of 5%MSUCN include pH values, inorganic ions, and organic matter. Finally, the deep photodegradation mechanisms of TC and intermediates were proposed based on ex situ HPLC-MS. This work not only explains the deep decomposition of TC but also presents a facile approach for designing and manufacturing carbon nitride nanohybrids. [ABSTRACT FROM AUTHOR]

As a member of the ternary sulfides, CdIn2S4 is a visible light responded catalyst with a band gap of 2.2–2.6 eV, which is suitable for solar spectrum. In this study, a simple two-step solvothermal method was used to construct Ni12P5/In(OH)3/CdIn2S4 composite catalysts with type-II and Z-scheme heterojunctions, and there was a synergy between the two heterojunctions. The Ni12P5/In(OH)3/CdIn2S4 composite catalyst formed a donor-mediator-acceptor system for photogenerated electrons, which greatly improved the separation efficiency of the photogenerated carriers. Moreover, the highest hydrogen production activity achieved by the Ni12P5/In(OH)3/CdIn2S4 composites was 5.75 mmol g−1 h−1, which was 21 times the original CdIn2S4. [ABSTRACT FROM AUTHOR]

Effective interfacial engineering to fabricate a suitable nano-photocatalyst for environmental remediation is on high demand. A magnetic nanocomposite is a potential candidate for reusability and recovery from treated wastewater. CuFe2O4/CdS nanoclusters (NCs) were fabricated using a chemical co-precipitation method. SEM and TEM images of the fabricated NCs revealed coral-like agglomerations and polycrystalline nature of NCs with clear lattice fringes. XPS and EDAX were performed for elemental analysis. The apparent photodegradation rate of dye by NCs is two-fold higher compared to that of pure CdS and CuFe2O4. The S-scheme interface retained both strong potential e−/h+ for ˙OH and ˙O2− production under visible light illumination. A 97.71% photocatalytic efficiency was retained after six cycles of reuse. This enhancement in the photocatalytic performance of NCs demonstrates their excellent potential to behave as environmental remediating agents. [ABSTRACT FROM AUTHOR]

The decomposition efficiency of refractory organic pollutants depends strongly on the characteristics of the photoanode semiconductors in the photoelectrocatalytic (PEC) process. The selection of superior materials with excellent PEC efficiency is a challenge in the practical application of PEC oxidation technology. Herein, a novel S-Co3O4/Bi2WO6 heterojunction photoanode was fabricated using a simple hydrothermal procedure. Compared with Bi2WO6 nanoflowers, the as-prepared S-Co3O4/Bi2WO6 photoanode had a large electroactive surface area, low charge transfer resistance, strong light absorption ability, and high separation efficiency for induced photogenerated electron/hole pairs (e−/h+). This relies on the fact that S doping not only controls the morphology of Co3O4 but also changes its intrinsic electronic structure to improve the interlayer polarization. Notably, the Z-scheme heterojunction formed by the combination of S-Co3O4 and Bi2WO6 not only enhances the e−/h+ separation efficiency but also results in a stronger redox ability than that of pure Bi2WO6. In addition, reactive species trapping experiments and electron spin resonance tests demonstrated that the S-Co3O4/Bi2WO6 photoanode plays a dominant role in the degradation of tetracycline (TC) by ˙O2− and ˙OH radicals. Therefore, the prepared S-Co3O4/Bi2WO6 photoanode exhibits better PEC performance than Co3O4, S-Co3O4 and Bi2WO6 in the degradation of TC. The optimized S-Co3O4/Bi2WO6 composite showed a degradation rate of 87.4% in 30 mg L−1 TC solution. This work provides a new strategy for the construction of efficient photoelectroanodes. [ABSTRACT FROM AUTHOR]

The importance of photocatalytic hydrogen evolution is increasing in energy research and environmental catalysis. Co-MOF, a metal–organic framework compound with a zeolite topological structure, has the advantage of being a semiconductor in photocatalytic applications. The new composite materials constructed by coupling Co-MOF with traditional semiconductors will significantly stimulate the potential of photocatalysis due to the construction of a heterogeneous interface. We accurately controlled the growth of Co-MOF with different morphologies by adjusting the ratio of raw materials. With the increase of dimethylimidazole, hexagonal prism morphology (Co-MOF-H), leaf morphology (Co-MOF-B), and Daisy morphology (Co-MOF-D) were successively synthesized. The experimental results show that H-g-C3N4 has the best catalytic activity when adsorbing hexagonal prism Co-MOF. When the ratio of H-g-C3N4 reached 125 mg, the optimal hydrogen evolution activity reached 1033 μmol g−1 h−1. Various characterization methods were used to explain the influence of morphology regulation on the hydrogen evolution ability of Co-MOF and explore the mechanism of hydrogen evolution of Co-MOF/H-g-C3N4 composite catalysts. [ABSTRACT FROM AUTHOR]

Elimination of antibiotics such as tetracycline hydrochloride (TC) from wastewater is of great significance, but still faces challenges. In this regard, Cu2O decorated CuZnAl-layered double hydroxide (Cu2O/CuZnAl-LDHs) heterostructure photocatalysts were designed via a facile coprecipitation method and subsequent in situ reduction approach. The XRD, XPS, UV-vis DRS, PL, Mott–Schottky plots, and VB-XPS results together revealed that the construction of a heterostructure inhibits the recombination of relatively useful electrons and holes, providing a strong driving force for the photocatalytic degradation of TC. Additionally, the synergistic effects increased visible light absorption and the population of adsorption sites, which also played pivotal roles in the removal of TC. As a result, the degradation efficiency of TC catalyzed by Cu2O/CuZnAl-LDHs under visible light reached 94.1% within 120 min. The capture experiments of active species and ESR analysis confirm that the superoxide radical (˙O2−), holes (h+) and hydroxyl radicals (˙OH) were responsible for the decomposition of TC. This study provides a rational design strategy and performance assessment of LDH-based heterostructured photocatalysts for the treatment of antibiotic-contaminated water. [ABSTRACT FROM AUTHOR]

We demonstrate a low-cost, simple-operation, and environmentally friendly magnetic grinding synthetic process to prepare nontoxic copper sulfide-based composites with photocatalytic activity. Using this efficient approach, CuS/ZnS and CuS/CdS composites were successfully synthesized from elemental powders without using any other additives or solvents. The formation of metal sulfides was confirmed using a series of characterizations. The photocatalytic activities of the as-prepared materials were evaluated by the degradation of methylene blue (MB), rhodamine B (RhB), and methyl orange (MO) dyes in the presence of hydrogen peroxide (H2O2), which served as an oxidant under visible irradiation. The degradation efficiencies of MB and RhB by CuS/ZnS and CuS/CdS composites were more than 95% in 30 min and the degradation efficiency of MO was more than 85% in 90 min. The photocatalytic activities of the CuS/ZnS and CuS/CdS composites were better than those of pure metal sulfides. In addition, the CuS/ZnS and CuS/CdS composites showed good stability toward photocatalytic degradation and their main reactive species for degrading organic dyes are photogenerated hydroxyl radical (˙OH). Reasonable photocatalytic reaction mechanisms are proposed to explain the photocatalytic processes of the CuS/ZnS and CuS/CdS composites. [ABSTRACT FROM AUTHOR]

Recently, the treatment of wastewater to remove antibiotics, such as oxytetracycline hydrochloride (OTC), has attracted much attention. In this work, coral-like HTiOF3 was used as a template to construct the small-scale nanomaterials {001}-TiO2, TiOF2/HTiOF3, and F-H2Ti3O7via different solvothermal methods. The crystal forms, structures, morphologies, optical properties, and charge separation properties of the obtained materials were thoroughly characterized using several techniques. Of these materials, F-H2Ti3O7 (KOH-HTF), synthesized via an alkali thermal synergistic ion exchange method, showed excellent OTC degradation activity (92%). The three-dimensional (3D) flower-like morphology of KOH-HTF enhances its OTC adsorption capacity. The co-modification of lattice fluorine and surface fluorine introduced in situ during the preparation of KOH-HTF brings a significant surface fluorine effect, which is not only conducive to the generation of Ti3+ and oxygen vacancies (Vos), but also conducive to the activation of OTC molecules and the migration of photogenerated electrons and holes. In addition, O2− has been proven to be the main active species in the photocatalytic process. It is proposed that the ligand-to-metal charge transfer effect between KOH-HTF and OTC is the key to improving the visible light response and carrier separation. A possible photocatalytic mechanism is also investigated. [ABSTRACT FROM AUTHOR]

A novel Cu-doped one dimensional (1D) Bi2S3 rod-shaped nanocapsule/rGO composite is explored as a photocatalyst for selective reduction of CO2 to methanol. In particular, the effects of Cu doping of rGO supported Bi2S3 on band gap tuning and on product selectivity are investigated. Bi2S3 rod-shaped nanocapsules and 0.5, 1, and 2 weight percent Cu-doped Bi2S3/rGO are synthesised through a hydrothermal approach. The photocatalysts are characterized by XRD, FTIR, UV-Vis spectroscopy, photoluminescence spectroscopy, X-ray photoelectron spectroscopy, and SEM, TEM and EDX analysis. It is revealed that Cu-doped Bi2S3/rGO for all different compositions offers selective and enhanced production of methanol compared to undoped Bi2S3/rGO, pristine Bi2S3, and Cu-doped Bi2S3 which produce formic acid along with methanol. The optimum 1 weight percent Cu-doped Bi2S3/rGO photocatalyst, exhibiting the smallest band gap and the lowest rate of recombination of electron–hole pairs, offers the highest photocatalytic activity of 719 μmol gcat.−1 h−1. DFT studies corroborate the experimental finding of a drastic reduction of the band gap (1.36 eV) of Cu-doped Bi2S3/graphene and unveil that Cu 3d–C 2p hybridization as well as enhancement of Bi 6p–C 2p hybridization in the presence of copper significantly increases the overall DOS of the system at the Fermi level, resulting in enhancement of electronic conductivity and charge transfer; further deformation in the graphene sheets due to the presence of Cu-Bi2S3 creates CO2 trapping sites for its efficient adsorption and selective photoreduction. [ABSTRACT FROM AUTHOR]

Converting the naturally available mechanical energy and solar energy into chemical energy holds great promise for exploiting renewables. Here, by coupling the piezoelectric effect of ZnO and the plasmon resonance of Ag nanoparticles, we construct a binary catalytic system, which can capture hydromechanical energy from fluids and visible light energy from sun to drive the degradation of tetracycline. Our research demonstrated that the mechanical stirring induced an inner electric field across the piezoelectric ZnO, while the light irradiation triggered plasmonic hot carriers in Ag NPs. These hot carriers injected into ZnO would be utilized to drive piezoelectric catalytic reactions. Our study broadens the horizon of piezo catalysis by utilizing low-density mechanical energy and coupling it with plasmonic photocatalysis. [ABSTRACT FROM AUTHOR]

Bismuth vanadate (BiVO4) is one of the most effective photoanode materials for photoelectrochemical water splitting, but its reaction rate is greatly limited by the poor separation efficiency of photo-generated charges and sluggish kinetics. In this work, a surface hydroxylation strategy was carried out to overcome the above-mentioned shortcomings. A simple post-synthetic NaOH immersion method was used to successfully hydroxylate the BiVO4 photoanode surface without affecting its bulk properties. The modified surface hydroxyl group not only promotes the photo-generated charge separation efficiency of hydroxylated BiVO4 but also tailors its local electronic structure to form high-valence Bi(3+x)+ states. The Bi(3+x)+ species serving as the active site is advantageous for water dissociation, thus decreasing the free energy barrier of the potential-determining step for the boosted overall water oxidation kinetics. As a result, the best hydroxylated BiVO4 photoanode achieves a higher photocurrent density of 1.14 mA cm−2 at 1.23 V vs. RHE under visible light irradiation, which is 4.75 times that of bare BiVO4 (0.24 mA cm−2), and moreover, a cathodic shift of 190 mV at 1 mA cm−2 is obtained. Our work affords a practical method with strong operability to improve the intrinsic photoelectrochemical performance of photoanodes by the efficient surface hydroxylation strategy. [ABSTRACT FROM AUTHOR]

Graphite carbon nitride (g-C3N4) has attracted much attention in the field of photocatalysis because of its visible light response and stable properties. However, its photocatalytic activity is not ideal because of its limited visible light response range, easy recombination of photogenerated electron holes, and poor dispersion. In this study, the visible light catalytic performance of g-C3N4 was significantly improved by the double modification method of surface hydroxyl and coupling agent grafting. Firstly, g-C3N4 was prepared by thermal polymerization with melamine as the raw material, and then the surface hydroxyl group was introduced by hydrogen peroxide. Finally, the organic groups were grafted on the surface of g-C3N4 by using silane coupling agent YDH171 as the grafting agent. The catalysts were characterized by FT-IR, XPS, XRD, contact angle measurements, UV-vis DRS, PL, electrochemical methods and particle size distribution. Taking simulated oily wastewater as the target material, the reaction rate of graphite carbon nitride was increased by 2.7 times after surface double modification. Moreover, a radical trap experiment was carried out, which indicated that the hole acted as the main reactive species for the photocatalytic degradation process. The catalytic mechanism of the material was investigated. The results showed that the synergistic effect of surface hydroxyl group grafting and coupling agent grafting increased the separation efficiency of photogenerated electron holes and improves their dispersion in water, thus promoting the photocatalytic performance of the catalyst. [ABSTRACT FROM AUTHOR]

Oxime ethers are of great importance in the field of pharmaceutical chemicals and polymer materials. Herein, we have developed a straightforward synthetic method to prepare oxime ethers starting from tetrahydrofuran or other cyclic ethers and various oxime derivatives with tetrabromomethane as a mediator. A plausible mechanism indicates that tetrabromomethane is first cleaved by visible light irradiation, and the derived radicals transform tetrahydrofuran into its cationic species, which then reacts with oxime to form the target oxime ethers with the formation of a C–O bond. This novel oxidative cross-coupling reaction can be carried out under transition metal-free and mild conditions with good functional group tolerance, and is easy to scale-up. [ABSTRACT FROM AUTHOR]

The development of an efficient, cost-effective, and stable visible-light-driven photocatalyst for the photodegradation of organic pollutants is a challenging task. Herein, the synthesis and characterization of a Ag2O–Co3O4 Z-scheme photocatalyst and evaluation of its photocatalytic performance are reported. An aqueous solution of a reactive yellow dye was used as a model organic pollutant. Co3O4 and Ag2O–Co3O4 were synthesized by precipitation and impregnation methods, respectively. Advanced techniques including XRD, DRS-UV-Vis, SEM, TEM, TGA, and XPS were employed for the characterization of the synthesized Ag2O–Co3O4. The prepared materials were tested as a catalyst for the degradation of the reactive yellow dye. It was found that coupling of Ag2O with Co3O4 enhanced the photocatalytic performance from 55 to 100% towards a 50 mL dye solution containing 100 mg L−1 of dye. The rate constant for Ag2O–Co3O4 catalyzed photodegradation of the reactive yellow dye was 2.8 times higher than the rate constant with Co3O4. The dependence of photocatalytic performance on experimental parameters like catalyst dosage, Ag2O content, recycling of the catalyst, and concentration of the dye was also investigated. The as-prepared Ag2O–Co3O4 was found to be an efficient, cost-effective, and stable Z-scheme photocatalyst for the photodegradation of the reactive yellow dye under visible light irradiation. [ABSTRACT FROM AUTHOR]

The design of organic photocatalysts with visible-light-response is an important way to solve energy crisis and environmental pollution. Polypyrrole (PPy) as one of the conjugated polymers is a prospective photocatalyst material due to its excellent optical properties, easy synthesis and high environmental stability. In this work, polyacrylonitrile (PAN) and g-C3N4 were electrospun as a fiber membrane matrix. PPy was coated on the matrix by in situ polymerization of a pyrrole monomer using doped Fe3+ as an oxidant. PPy exhibited a broadband visible light absorption region and a narrow band gap which was conducive to improve visible light utilization. The separation efficiency of photogenerated e−–h+ pairs was improved by constructing a heterojunction between PPy and g-C3N4. The doping of Fe3+ as an electron scavenger further prevented the recombination of carriers. The PAN/g-C3N4-PPy-Fe3+ membrane showed highly efficient removal performance for both cationic and anionic dyes. Moreover, PAN/g-C3N4-PPy-Fe3+ exhibited excellent recyclability and stability. This work outlined an approach for designing a novel conjugated polymer based multi-component composite photocatalyst with visible light response. [ABSTRACT FROM AUTHOR]

The effects of Zn precursors, S precursors and hydrothermal temperatures on the morphologies and structures of ZnS microspheres were investigated by a facile hydrothermal method. The results showed that the mixed phase ZnS microspheres prepared with ZnCl2 and L -cysteine at 180 °C exhibited a visible light response. The as-prepared ZnS microspheres were used for photodegradation of rhodamine B (RhB), methyl orange (MO) and methylene blue (MB). The photodegradation rates of ZnS microspheres to these azo dyes were 87.5% (RhB), 84.3% (MB), and 65.3% (MO), respectively. In addition, ZnS microspheres maintained good photodegradation activity after four cycles. In this work, ˙O2− was the major active species and the possible photocatalytic mechanism of ZnS microspheres was also illustrated. [ABSTRACT FROM AUTHOR]

A novel and effective blue LED-induced methodology has been developed to synthesize a number of 6-alkyl(aryl)phenanthridines from isocyanobiaryls and alkyl(aryl)sulfinates in ethyl lactate under aerobic conditions. This protocol did not require a photoredox catalyst, and the reaction was sparked by the photochemical activity of an electron donor–acceptor complex formed by the interaction of isocyanobiaryls with alkyl(aryl)sulfinates. The environmental friendliness, mildness, gram-scale synthesizability, lack of toxic organic solvents/additives, and lack of a transition metal are only a few notable advantages of this methodology. [ABSTRACT FROM AUTHOR]

Realizing highly efficient utilization of solar energy for solving problems of environmental pollution and energy shortage has attracted increasing attention. Herein, Z-scheme two-dimensional (2D)/2D NiCo-LDH/g-C3N4 (LDH/CN) heterojunction composites were synthesized, which showed enhanced photocatalytic performance for tetracycline hydrochloride (TC) degradation and hydrogen (H2) generation under visible light irradiation. A 2D/2D heterojunction structure was formed between NiCo-LDH nanosheets (LDH) and g-C3N4 (CN), which was beneficial for the effective separation of photogenerated charge carriers. The active species of hydroxyl (˙OH), superoxide (˙O2−) and hole (h+) radicals contributed to TC photodegradation. The optimum photocatalyst showed a remarkably enhanced photocatalytic capability with a hydrogen generation rate of 451.7 μmol g−1 h−1. The improved photocatalytic activities may be attributed to the synergistic effects of the increased absorption of visible light, the separation efficiency of carriers and the 2D/2D heterostructure. A Z-scheme photocatalytic mechanism was proposed for the LDH/CN composite, showing dual advantages of a high redox ability and efficient charge carrier separation. [ABSTRACT FROM AUTHOR]

A novel AgI/Ag6Si2O7/PET Z-scheme heterojunction photocatalyst with strong redox capability was fabricated via a facile successive ionic layer adsorption and reaction (SILAR) method to degrade methyl orange (MO). Compared with Ag6Si2O7/PET and AgI/PET, the prepared AgI/Ag6Si2O7/PET heterojunction exhibits superior photocatalytic performance under visible light because of its strong interfacial coupling effects. The degradation rate constant of the optimal AgI/Ag6Si2O7/PET is up to 0.144 min−1, which is approximately 5.5 and 9.6 times greater than that of Ag6Si2O7/PET and AgI/PET, respectively. The radical capture experiments and ESR characterization demonstrate that h+ and ˙O2− are two major oxidative species responsible for the photocatalytic degradation of dyes. The PL, photocurrent and EIS analyses indicate that AgI/Ag6Si2O7/PET shows enhanced electron–hole pair separation efficiency. This phenomenon is related to three aspects, namely the high light-harvesting efficiency, greatly enhanced accessibility to the active site, and the formation of Z-scheme heterojunction structures that effectively improve the photoelectron–hole separation efficiency and the redox capacity of the photocatalyst. Our work, therefore, provides novel insights into the development of a heterojunction composite with boosted photocatalytic activity, excellent stability, and reusability for the degradation of organic pollutants. [ABSTRACT FROM AUTHOR]

Tröger's base analogs (TBAs) present a pair of uniquely bent tetracyclic scaffolds that possess two stereogenic amine groups with identical handedness. This work employs TBAs as chiral building blocks in the design of electron-rich (electron-donating) macrocycles, namely enantiopure Trögerophanes. These chiral donor macrocycles are then mechanically interlocked with an achiral electron-deficient (electron-acceptor) macrocycle—namely, cyclobis(paraquat-p-phenylene) (CBPQT4+)—that carries four positive charges. These electron donor and acceptor components are individually colorless but once mechanically interlocked to one another they generate a charge-transfer (CT) absorption band centered at around 525 nm turning the resulting chiral 2-catenanes purple in color. Strikingly, the circular dichroism spectra of the two opposing enantiomers of this 2-catenane show mirroring patterns and a Cotton effect in the region that corresponds to the CT mainly from 445 to 625 nm. This phenomenon attests to the transfer of chirality from the chiral donor Trögerophane to the achiral acceptor CBPQT4+ macrocycle and the amplification of chiroptical properties of the interlocked molecule whose structure is almost entirely rigid. Moreover, this work demonstrates the discriminatory interactions of the nitrogen-based stereocenters of Tröger's base with chiral acids. This discriminatory property enables the investigated chiral 2-catenane showing a moderate enantioenrichment while interacting with an amino acid and oxidizing it in a competitive photocatalytic aerobic oxidation process fueled by the energy of visible light absorbed within the CT region. [ABSTRACT FROM AUTHOR]

Introducing the photothermal effect to promote the photocatalytic H2 rate is a good strategy and is gradually gaining attention. In this work, a series of ultrathin Bi2Se3/CdS nanocomposites were prepared by hydrothermal method and in situ precipitation method. Notably, CdS nanoparticles are monodispersed on the surface and aggregated at the edge of ultrathin Bi2Se3 nanosheets, as shown by the TEM images, implying the formation of a tight interface and rich active sites with a large area. As expected, the composite displays an excellent photocatalytic H2 rate under visible light irradiation, which is about 3.2 times higher than that of pristine CdS. The DRS analysis shows that Bi2Se3 endowed the Bi2Se3/CdS composite with a stronger absorption ability and a wider visible absorption range. The PL, SPV, and electrochemical tests all demonstrate that the transfer and separation of electron–holes are greatly enhanced. Furthermore, the composite exhibits good solar-to-heat conversion efficiency under full-spectrum light illumination, which is beneficial to the charge activation and transfer rate. Based on the obtained band structure, the superior photocatalytic ability of the Bi2Se3/CdS composite is ascribed to the synergetic effect of the heterojunction and the strong solar-to-heat conversion. The work provides a strategy for employing photothermal conversion to improve solar energy conversion. [ABSTRACT FROM AUTHOR]

Developing effective antimicrobials while avoiding drug resistance remains a challenge. Using a simple in situ polymerization method, this study incorporated carbon quantum dots (CQDs) in a three-component composite PPy/MoS2/CQD with a core–shell structure. The as-prepared composites indicated photocatalytic antibacterial activity. In the vitro antibacterial trials, a much higher bactericidal rate was achieved upon irradiation with visible light for 24 hours than under dark conditions. Moreover, the antibacterial effects of PPy/MoS2/CQD composites indicated similar antimicrobial effects against both general and drug-resistant bacteria owing to their unique antimicrobial mechanism, wherein the core–shell structure enhances the lifetime of photo-induced electrons and holes, leading to the effective production of a large number of reactive oxygen species and inhibiting bacteria growth. In conclusion, PPy/MoS2/CQD nanomaterials are promising antimicrobials for treating both regular and drug-resistant bacteria. [ABSTRACT FROM AUTHOR]