Defect and Heterostructure engineering assisted S-scheme Nb2O5 nanosystems-based solutions for environmental pollution and energy conversion

This review explores the crystallographic versatility of niobium pentoxide (Nb2O5) at the nanoscale, showcasing enhanced catalytic efficiency for cutting-edge sustainable energy and environmental applications. The synthesis strategies explored encompass defect engineering, doping engineering, s-scheme formation, and heterojunction engineering to fine-tune the physicochemical attributes of diverse dimensional (0-D, 1-D, 2-D, and 3-D) Nb2O5 nanosystems as per targeted application. In addressing escalating environmental challenges, Nb2O5 emerges as a semiconductor photocatalyst with transformative potential, spanning applications from dye degradation to antibiotic and metal removal. Beyond its environmental impact, Nb2O5 is pivotal in sustainable energy applications, specifically in carbon dioxide and hydrogen conversion. However, challenges such as limited light absorption efficiency and scalability in production methods prompt the need for targeted research endeavors. The review details the state-of-the-art Nb2O5 nanosystems engineering, tuning their physicochemical properties employing material engineering, and their high catalytic performance in environment remediation and energy generation. It outlines challenges, potential mitigation strategies, and prospects, urging for developing greener synthesis routes, advanced charge transfer techniques, targeted optimization for specific pollutants, and application for micro/nano plastics photocatalytic reduction. As researchers and environmental stewards collaborate, Nb2O5 stands poised at the intersection of environmental remediation, energy harvesting, and nanomaterial advancements, offering a beacon of progress toward a cleaner, more sustainable future.

Ag@MUT-16 nanocomposite as a Fenton-like and plasmonic photocatalyst for degradation of Quinoline Yellow under visible light

A new cobalt-based metal-organic framework with the chemical formula of [Co2(DClTPA)2(DABCO)]·(DMF)4 (MUT-16) containing 1,4-diazabicyclo[2.2.2]octane (DABCO) and 2,5-dichloroterephthalic acid (DClTPA) has been designed and prepared through a solvothermal method. MUT-16 (MUT = Materials from University of Tehran) crystallized in a tetragonal system with I41/acd space group, based on single-crystal X-ray analysis. The Ag@MUT-16 nanocomposite was prepared using Ag nanoparticles (NPs) loaded into/onto porous MUT-16via photoreduction route (PR). The MUT-16 and Ag@MUT-16 were characterized using various techniques, such as PXRD, FT-IR, FE-SEM, TEM, EDX, N2 adsorption-desorption isotherms, TGA, DRS, PL, EIS, and Mott-Schottky measurements. The Ag@MUT-16 nanocomposite showed photocatalytic activity of 87.75% in the degradation of Quinoline Yellow (QY) after 30 min under visible light irradiation. The distinctive characteristics of the Ag@MUT-16 nanocomposite, such as the Fenton-like effect of Co2+ ions, surface plasmon resonance (SPR) of Ag NPs, Schottky junction at interfaces between Ag NPs and MUT-16, and reduction of electron-hole recombination through electron trapping by Ag NPs as co-catalyst, all play significant roles in the photocatalytic degradation of Quinoline Yellow (QY).

Recent Developments in Nickel-Based Layered Double Hydroxides for Photo(-/)electrocatalytic Water Oxidation

Layered double hydroxides (LDHs), especially those containing nickel (Ni), are increasingly recognized for their potential in photo(-/)electrocatalytic water oxidation due to the abundant availability of Ni, their corrosion resistance, and their minimal toxicity. This review provides a comprehensive examination of Ni-based LDHs in electrocatalytic (EC), photocatalytic (PC), and photoelectrocatalytic (PEC) water oxidation processes. The review delves into the operational principles, highlighting similarities and distinctions as well as the benefits and limitations associated with each method of water oxidation. It includes a detailed discussion on the synthesis of monolayer, ultrathin, and bulk Ni-based LDHs, focusing on the merits and drawbacks inherent to each synthesis approach. Regarding the EC oxygen evolution reaction (OER), strategies to improve catalytic performance and insights into the structural evolution of Ni-based LDHs during the electrocatalytic process are summarized. Furthermore, the review extensively covers the advancements in Ni-based LDHs for PEC OER, including an analysis of semiconductors paired with Ni-based LDHs to form photoanodes, with a focus on their enhanced activity, stability, and underlying mechanisms facilitated by LDHs. The review concludes by addressing the challenges and prospects in the development of innovative Ni-based LDH catalysts for practical applications. The comprehensive insights provided in this paper will not only stimulate further research but also engage the scientific community, thus driving the field of photo(-/)electrocatalytic water oxidation forward.

Facile fabrication of B-rGO/ZnFe2O4 p-n heterojunction-based S-scheme exciton engineering for photocatalytic Cr(vi) reduction: kinetics, influencing parameters and detailed mechanism

The fabrication of p-n heterostructures was found to be an effective strategy to stimulate the interfacial exciton shipment and photocatalytic reactions. Herein, we report a p-n junction synthesized by combining p-type boron-doped reduced graphene oxide (B-rGO) with an n-type ZnFe2O4 semiconducting material for Cr(vi) reduction under LED light irradiation. The band structures of ZnFe2O4 and B-rGO were evaluated using UV-vis spectroscopy, Mott-Schottky (M-S) plots and photocurrent studies. The results indicated that ZnFe2O4 and B-rGO exhibit a conventional type-II charge transfer, and the Fermi-level (E F) of ZnFe2O4 was found to be much lower than that of the B-rGO material. Based on these investigations, an S-scheme charge-migration pathway was suggested and demonstrated by the photocatalytic activity and nitroblue tetrazolium (NBT) chloride experiments. The optimal 2 wt% B-rGO/ZnFe2O4 heterojunction exhibits the highest photocatalytic performance, i.e. 84% of Cr(vi) reduction in 90 min under 20 W LED light irradiation with a rate constant of 0.0207 min-1, which was 4.6- and 2.15-fold greater than that of ZnFe2O4 (ZnF) and B-rGO, respectively. The intimate interfacial contact, excellent photon-harvesting properties, effective exciton segregation and availability of active electrons are some factors responsible for enhanced photocatalytic Cr(vi) reduction. In order to fulfill the demand of applied waste-water management, the influences of various photocatalyst amounts, pH values and co-exiting ions on photocatalytic activities were evaluated. Finally, this work provides a way to fabricate S-scheme-based p-n-heterostructures for photocatalytic wastewater treatment.

Synthesis of magnetic layered double hydroxide (Fe3O4@CuCr-LDH) decorated with ZIF-8 for efficient sonocatalytic degradation of tetracycline

A series of Fe3O4@CuCr-LDH hybrids decorated with different amount of ZIF-8 (FLZ, 10-40 wt%) was prepared using simple methods and characterized with different techniques. The activity of the synthesized nanocomposites was investigated in the sonocatalytic degradation of tetracycline (TC) antibiotic from wastewater. When the content of ZIF-8 in the nanocomposite structure was 20 wt%, the FLZ-20 sonocatalyst exhibited the high performance in the sonocatalytic removal of TC. At optimum conditions (0.7 g/L catalyst dosage, pH of 7, 50 mg/L initial concentration of antibiotic, and 15 min sonication time) of the sonocatalytic removal of TC approached to 91.4% under ultrasonic irradiation (USI) using FLZ-20. This efficiency was much higher than those of obtained results by Fe3O4@CuCr-LDH and pristine ZIF-8. The formed ●OH and ●O2- exhibited the major roles in the sonocatalytic TC degradation process. The excellent performance of FLZ-20 can be attributed to the heterojunctions created between composite components, which could improve the electron transfer ability and effectively separate e-/h+ pairs. In addition, FLZ-20 showed the superior reusability and stability during three successive recycling. Moreover, the facile magnetically separation of the sonocatalyst from the aqueous solution was another outstanding feature, which prevents the formation of secondary pollutants. It can be concluded that the fabrication of heterojunctions is an efficient procedure to promote the sonocatalytic acting of the catalyst.

Tuned CuCr layered double hydroxide/carbon-based nanocomposites inducing sonophotocatalytic degradation of dimethyl phthalate

This study is the first to explore the possibility of utilizing CuCr LDH decorated on reduced graphene oxide (rGO) and graphene oxide (GO) as sonophotocatalysts for the degradation of dimethyl phthalate (DMP). CuCr LDH and its nanocomposites were successfully fabricated and characterized. Scanning electron microscopy (SEM) along with high-resolution transmission electron microscope (HRTEM) both evidenced the formation of randomly oriented nanosheet structures of CuCr LDH coupled with thin and folded sheets of GO and rGO. The impact of diverse processes on the degradation efficiency of DMP in the presence of the so-prepared catalysts was compared. Benefiting from the low bandgap and high specific surface area, the as-obtained CuCr LDH/rGO represented outstanding catalytic activity (100 %) toward 15 mg L-1 of DMP within 30 min when subjected to light and ultrasonic irradiations simultaneously. Radical quenching experiments and visual spectrophotometry using an O-phenylenediamine revealed the crucial role of hydroxyl radicals compared to holes and superoxide radicals. Overall, outcomes disclosed that CuCr LDH/rGO is a stable and proper sonophotocatalyst for environmental remediation.

Inactivation mechanism of E. coli in water by enhanced photocatalysis under visible light irradiation

Developing efficient and economical technologies for drinking water disinfection remains a challenge. We synthesized Ag/AgBr/LDH doped with various silver mass concentrations and explored its ability to inactivate E. coli under visible light irradiation (λ ≥ 400 nm). Our results indicated a total inactivation of E. coli (10⁷ CFU·mL^-1) within 80 min using 2 % Ag/AgBr/LDH in a laboratory-scale test. The method was evaluated for disinfecting three effluent samples collected from one drinking water treatment plant, covering representative water treatment processes. After five consecutive runs, the inactivation efficiency decreased slightly to 89 % in CFU·mL^-1, indicating that the photocatalysts had excellent stability and reusability. The mechanisms were analyzed by combining chemical and biological methods. It was verified that singlet oxygen (¹O₂), hydrogen peroxide (H₂O₂), and photo-generated electrons (e^-) were significant contributors to the inactivation process. Scanning electron microscopy images analysis showed the disruption of the membrane integrity of E. coli by photocatalytic oxidation. Internal component leakage and reduced enzyme activity were also observed in terms of K⁺ leakage, β-galactosidase activity, and antioxidant enzyme activity. The results by the transcriptomic analysis implied that Ag/AgBr/LDH regulating the oxidative stress response and cell membrane damage related genes was the main inactivation mechanism.

Oxygen Vacancies Regulated Selective Hydrogenation of α,β-unsaturated Aldehydes over LDH Surface Group Coordinated Transition Metal Photocatalysts

Selective hydrogenation of α,β-unsaturated aldehydes under mild conditions is a great challenge in achieving synthesis of corresponding alcohols. Herein, we report that a series of oxygen vacancies enriched MgAl-LDH coordinated...

A novel Z-scheme Bi-Bi2O3/KTa0.5Nb0.5O3 heterojunction for efficient photocatalytic conversion of N2 to NH3

A novel Z-scheme photocatalyst Bi-Bi2O3/KTa0.5Nb0.5O3 (KTN) composite was prepared by a simple solvothermal method. Compared with KTN, Bi/KTN, and Bi2O3/KTN, Bi-Bi2O3/KTN ternary composite catalyst presented much better photocatalytic ammonia-synthesis efficiency....

Robust charge carrier engineering via plasmonic effect and conjugated Π-framework on Au loaded ZnCr-LDH/RGO photocatalyst towards H2 and H2O2 production

Au loaded ZnCr-LDH/RGO ternary photocatalyst for H2 and H2O2 production under visible light illumination.

Graphene-based ZnCr layered double hydroxide nanocomposites as bactericidal agents with high sonophotocatalytic performances for degradation of rifampicin

Herein, ZnCr layered double hydroxide (ZnCr LDH), and its nanocomposites with GO and rGO were synthesized using the co-precipitation method. The samples were characterized using XRD, FT-IR, SEM, TEM, BET, and XPS techniques. The sonophotocatalytic activity of the ZnCr LDH, ZnCr LDH/GO, and ZnCr LDH/rGO was investigated via the degradation of rifampicin (RIF) in the ultrasonic bath under visible light irradiation. The synergy index of more than 1 determined for ZnCr LDH/rGO indicated the positive interaction of sonocatalysis and photocatalysis resulted by hybridizing the LDH nanosheets with rGO. The maximum sonophotocatalytic degradation efficiency of 87.3% was achieved in the presence of ZnCr LDH/rGO nanocomposite with the concentration of 1.5 g L^-1 for degradation of RIF with an initial concentration of 15 mg L^-1 within 60 min sonication under visible light irradiation. The addition of different scavengers indicated that hydroxyl radicals, superoxide anion radicals, and the generated holes played a dominant role in the degradation of the pollutant molecules. A possible degradation mechanism was suggested based on the intermediates. The antibacterial tests confirmed the higher antibacterial activity of ZnCr LDH/GO compared with ZnCr LDH and ZnCr LDH/rGO against Gram-positive Staphylococcus aureus.

Synthesis, Characterization and Photocatalytic Performance of Calcined ZnCr-Layered Double Hydroxides

The development of new materials for performing photocatalytic processes to remove contaminants is an interesting and important research line due to the ever-increasing number of contaminants on our planet. In this sense, we developed a layered double hydroxide material based on Zn and Cr, which was transformed into the corresponding oxide by heat treatment at 500 °C. Both materials were widely characterized for their elemental composition, and structural, morphological, optical and textural properties using several experimental techniques such as x-ray diffraction, x-ray photoelectron spectroscopy, scanning and transmission electron microscopy, Fourier transform infrared spectroscopy, UV-vis spectroscopy and physisorption techniques. In addition, the photocatalytic activity of both materials was analysed. The calcined one showed interesting photocatalytic activity in photodegradation tests using crystal violet dye. The operational parameters for the photocatalytic process using the calcined material were optimised, considering the pH, the initial concentration of the dye, the catalyst load, and the regeneration of the catalyst. The catalyst showed good photocatalytic activity, reaching a degradation of 100% in the optimised conditions and showing good performance after five photodegradation cycles.

Ag/LDH-itaconic acid-gellan gam nanocomposites: Facile and green synthesis, characterization, and excellent catalytic reduction of 4-nitrophenol

The catalytic reduction reaction is one of the most commonly used solutions to convert high-risk contaminants into safe or low-risk materials. Today, with the increasing water pollution, the urgent need for efficient and effective catalysts is felt more than ever. For this purpose, for the first time, a green catalyst composed of silver nanoparticles anchored on itaconic acid-modified Ca-Al layered double hydroxide/gellan gum nanocomposite (Ag/LDH-ITA-GG NC) was prepared from a green approach without the use of any toxic organic solvents. To gain an in-depth insight into the physicochemical properties of the catalyst, different techniques including nitrogen adsorption-desorption isotherms, FESEM/mapping, FTIR, TGA, and XRD were used. The catalytic performance of the Ag/LDH-ITA-GG NC toward 4-nitrophenol reduction by NaBH₄ was investigated. The calculated values of the apparent rate constant for this reaction are 0.2142 min^-1 (for 1.0 mg of the catalyst), 0.2375 min^-1 (for 3.0 mg of the catalyst), and 0.2550 min^-1 (for 5.0 mg of the catalyst), indicating that the catalytic conversion of 4-nitrophenol to 4-aminophenol on the Ag/LDH-ITA-GG NC catalyst follows the pseudo-first-order kinetics and is comparable to the previous findings in the literature. The results of this study indicated that Ag/LDH-ITA-GG NC can potentially be utilized as an auspicious high efficient green catalyst for the reduction of pollutants like 4-nitrophenol.

Recent Progress on Metal-Enhanced Photocatalysis: A Review on the Mechanism

Metal-enhanced photocatalysis has recently received increasing interest, mainly due to the ability of metal to directly or indirectly degrade pollutants. In this review, we briefly review the recent breakthroughs in metal-enhanced photocatalysis. We discussed the recent progress of surface plasmon resonance (SPR) effect and small size effect of metal nanoparticles on photocatalysis; in particular, we focus on elucidating the mechanism of energy transfer and hot electron injection/transfer effect of metal nanoparticles and clusters while as photocatalysts or as cophotocatalysts. Finally, we discuss the potential applications of metal-enhanced photocatalysis, and we also offer some perspectives for further investigations.

The construction of a dual direct Z-scheme NiAl LDH/g-C3N4/Ag3PO4 nanocomposite for enhanced photocatalytic oxygen and hydrogen evolution

Dual direct Z-scheme photocatalysts for overall water decomposition have demonstrated strong redox abilities and the efficient separation of photogenerated electron-hole pairs. Overall water splitting utilizing NiAl-LDH-based binary and ternary nanocomposites has been extensively investigated. The synthesized binary and ternary nanocomposites were characterized via XRD, FTIR, SEM, HRTEM, XPS, UV-DRS, and photoelectrochemical measurements. The surface wettability properties of the prepared nanocomposites were measured via contact angle measurements. The application of the NiAl-LDH/g-C3N4/Ag3PO4 ternary nanocomposite was investigated for photocatalytic overall water splitting under light irradiation. In this work, we found that in the presence of Ag3PO4, the evolution of H2 and O2 is high over LCN30, and 2.8- fold (O2) and 1.4-fold (H2) activity increases can be obtained compared with the use of LCN30 alone. It is proposed that Ag3PO4 is involved in the O2 evolution reaction during water oxidation and g-C3N4 is involved in overall water splitting. Our work not only reports overall water splitting using NiAl-LDH-based nanocomposites but it also provides experimental evidence for understanding the possible reaction process and the mechanism of photocatalytic water splitting. Photoelectrochemical measurements confirmed the better H2 and O2 evolution abilities of NiAl-LDH/g-C3N4/Ag3PO4 in comparison with NiAl LDH, g-C3N4, Ag3PO4, and LCN30. The observed improvement in the gas evolution properties of NiAl LDH in the presence of Ag3PO4 is due to the formation of a dual direct Z-scheme, which allows for the easier and faster separation of charge carriers. More importantly, the LCNAP5 heterostructure shows high levels of H2 and O2 evolution, which are significantly enhanced compared with LCN30 and pure NiAl LDH.

Solvothermal synthesis and photocatalytic activities of cubic potassium tantalite and cuprum doped potassium tantalite

KTaO₃ and Cu²⁺ doped KTaO₃ were prepared by a solvothermal process. The measurements of XRD, FTIR, XPS, SEM, BET specific surface area, DRS, photoluminescence, photocurrent and electrochemical impedance spectroscopy measurements were carried out to investigate their physical and chemical properties. Especially, the photocatalytic activities of them were revealed by the photocatalysis of MB with irradiation of light in UV-Vis region. The measurements indicate that the Cu²⁺ doping does not obviously influence the phase and microstructure of KTaO₃, but highly changes the optical and electrochemical properties. Cu²⁺ doped KTaO₃ shows higher photocatalytic activity than KTaO₃ in the degradation of methylene blue with irradiation of light in UV-Vis region, which results from the enhanced light absorbance, more efficient transfers and separation of photogenerated charge carriers.

Recent Progress on Metal-Enhanced Photocatalysis: A Review on the Mechanism

Metal-enhanced photocatalysis has recently received increasing interest, mainly due to the ability of metal to directly or indirectly degrade pollutants. In this review, we briefly review the recent breakthroughs in metal-enhanced photocatalysis. We discussed the recent progress of surface plasmon resonance (SPR) effect and small size effect of metal nanoparticles on photocatalysis; in particular, we focus on elucidating the mechanism of energy transfer and hot electron injection/transfer effect of metal nanoparticles and clusters while as photocatalysts or as cophotocatalysts. Finally, we discuss the potential applications of metal-enhanced photocatalysis, and we also offer some perspectives for further investigations.

Facile hydrothermal synthesis of novel Fe-Cu layered double hydroxide/biochar nanocomposite with enhanced sonocatalytic activity for degradation of cefazolin sodium

This study reports the successful synthesis of Fe-Cu layered double hydroxide (Fe-Cu-LDH) /biochar (BC) nanocomposite by a hydrothermal method. The sonocatalytic performance of Fe-Cu-LDH/BC nanocomposite was investigated for the degradation of cefazolin sodium (CFZ), as a model emerging contaminant, from the solution. The physico-chemical properties of the synthesized samples were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDX), Brunauer-Emmett-Teller (BET), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR), and UV-Vis diffuse reflectance spectroscopy (DRS) analyses. The best sonocatalytic efficiency of 97.6% was achieved by using 1.0 g/L sonocatalyst, 0.1 mM CFZ, and an ultrasonic power of 300 W at pH = 6.5 (natural) within 80 min. Additionally, the effects of the addition of various oxidants, dissolved gases, and organic and inorganic scavengers on the degradation of CFZ were studied. Moreover, the possible sonocatalytic mechanism of the sonochemical degradation of CFZ in the presence of Fe-Cu-LDH/BC sonocatalyst was proposed based on the results of GC-MS analysis. The mineralization of CFZ solution was evaluated using COD and IC analyses. Finally, the reusability test of Fe-Cu-LDH/BC nanocomposite in the CFZ degradation revealed that almost 9% drop occurred after five successive cycles.

Superactive NiFe-LDH/graphene nanocomposites as competent catalysts for water splitting reactions

Adaptable strategies for the design of superactive NiFe-LDH/graphene nanocomposites for high-performance catalytic activity towards electrocatalytic, photoelectrocatalytic, and photocatalytic water splitting have been reviewed.

Double charge carrier mechanism through 2D/2D interface-assisted ultrafast water reduction and antibiotic degradation over architectural S,P co-doped g-C3N4/ZnCr LDH photocatalyst

S,P co-doped g-C₃N₄/ZnCr LDH 2D/2D heterostructure for photocatalytic ciprofloxacin degradation and H₂ evolution under the visible light irradiation.

An advanced composite with ultrafast photocatalytic performance for the degradation of antibiotics by natural sunlight without oxidizing the source over TMU-5@Ni–Ti LDH: mechanistic insight and toxicity assessment

Pharmaceuticals are considered as emerging organic contaminants that have become a serious environmental problem, which endanger human health and environmental bio-diversity.

Construction of a Z-Scheme Dictated WO3-X /Ag/ZnCr LDH Synergistically Visible Light-Induced Photocatalyst towards Tetracycline Degradation and H2 Evolution

Herein, we have designed nonstoichiometric WO₃, coupled with ZnCr layered double hydroxide (LDH) nanosheeet through Ag nanoparticle as the solid-state electron mediator to form WO_3-X /Ag/ZnCr LDH Z-scheme photocatalyst. The presence of oxygen defect levels in as-synthesized materials was confirmed by Raman, X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) analyses. The photocatalytic performance of the catalysts was investigated by the tetracycline degradation and H₂ energy production under visible light irradiation. The WO_3-X /Ag/ZnCr LDH ternary heterostructure exhibits superior activity toward tetracycline degradation and hydrogen evolution. The excellent photocatalytic performance of the catalyst was attributed to the synergistic effects among three species (WO_3-X , Ag, and ZnCr LDH) and the enhanced separation efficiency of photoinduced charge carriers through the Z-scheme WO_3-X /Ag/ZnCr LDH system. In addition, the created oxygen deficiency on WO_3-X could improve the photocatalytic behavior of ZnCr LDH in heterostructure by delaying the recombination efficiency of photoexcited electron-hole pairs. Furthermore, the higher affinity of tetracycline at the oxygen defect levels of the photocatalyst supports the high rate of tetracycline degradation. The enhanced photocatlytic activity of the catalysts was further supported by PL spectra and photoelectrochemical studies (electrochemical impedance spectroscopy (EIS) and linear sweep voltammetry (LSV) plot). The present research opens up a new strategy for designing highly efficient visible light-induced Z-scheme-based photocatalysts with high population of active sites for energy and environmental applications in a sustainable manner.

Facile Synthesis of a Polycatenane Compound Based on Ag-triazole Complexes and Phosphomolybdic Acid for the Catalytic Epoxidation of Olefins with Molecular Oxygen

A simple and efficient approach was developed for synthesizing a metal-organic polycatenated compound composed of Ag-triazole complexes and phosphomolybdic acid (PMA) clusters. The hybrid compound, namely {[Ag2(trz)2] [Ag24(trz)18]}[PMo12O40]2 (1) (trz = 1,2,4-triazole), showed high catalytic activity, selectivity and recyclability for the epoxidation of olefins with molecular oxygen as the oxidant and isobutyraldehyde as the co-reagent, and could even work well under ambient conditions. The special polycatenane framework, formed by interlocking [Ag24(trz)18]6+ nanocages, provides suitable space for filling the PMA clusters. The existence of multi-interactions, including π-π stacking, Ag-Ag interactions, and electrostatic interactions, should play a determinative role in fabricating the catalytically active and stable PMA-based polycatenane catalyst for aerobic epoxidation of olefins.

Enhanced photocatalytic performance of a Ti-based metal-organic framework for hydrogen production: Hybridization with ZnCr-LDH nanosheets

Novel hybrid composites of NH₂-MIL-125(Ti) and ZnCr-layered double hydroxide nanosheets (ZnCr-LDH NSs) are developed for use as visible-light-active photocatalysts for hydrogen production based on water photolysis. The hybrid composites are obtained by growing NH₂-MIL-125(Ti) in the presence of exfoliated ZnCr-LDH NSs using a solvothermal reaction. Hybridization of NH₂-MIL-125(Ti) with exfoliated ZnCr-LDH NSs leads to significant effects on the morphology and optical properties of NH₂-MIL-125(Ti). To find the optimum photocatalytic activity for hydrogen production by the hybrid composite photocatalysts, the content of ZnCr-LDH in this work is controlled. Compared to that of pristine NH₂-MIL-125(Ti) and ZnCr-LDH, the hybrid composites exhibit an improved photocatalytic activity for hydrogen production under visible-light irradiation. In addition, the hybrid composite photocatalyst shows excellent photo-chemical stability. The improved photocatalytic activity is believed to benefit from the synergy of strong electronic coupling between NH₂-MIL-125(Ti) and ZnCr-LDH NSs, expanded light absorption and band alignment to enhance the lifetime of photo-induced electrons and holes.

Facile construction of a novel NiFe2O4@P-doped g-C3N4 nanocomposite with enhanced visible-light-driven photocatalytic activity

Construction of a Z-scheme-based photocatalyst, i.e., NiFe₂O₄@P-g-C₃N₄ nanocomposite, was successfully fabricated by coupling phosphorus-doped g-C₃N₄ with spinel structure NiFe₂O₄. The structural, morphological, and spectroscopic data of the as-synthesized photocatalyst was successfully characterized through XRD, FTIR, SEM, TEM, UV-Vis DRS, PL, and XPS techniques. It was found that NiFe₂O₄@P-g-C₃N₄ had an increased light-absorption capacity, high exciton separation, low photogenerated electron-hole recombination, and showed better photocatalytic activity toward phenol oxidation and hydrogen energy production than the neat materials. Photocatalytic phenol oxidation by 20 wt% NFO@P-CN was also superior and could achieve a 96% conversion, which was 2 and 3 times higher than that by P-CN and NFO, respectively. The 20 wt% NFO@P-CN showed excellent photostability and was able to evolve 904 μmol h^-1 H₂ under visible-light irradiation. The enhanced photocatalytic activity of NiFe₂O₄@P-g-C₃N₄ was in good agreement with the photocurrent results. The synergistic effect between P-CN and NFO could accelerate photogenerated charge separation and, moreover, the distinctive magnetism of NiFe₂O₄@P-g-C₃N₄ aided the collection and recycling of the photocatalyst.

Electrochemical exploration of the effects of calcination temperature of a mesoporous zinc vanadate anode material on the performance of Na-ion batteries

As transition metal oxides are attractive candidates for energy storage applications, the spinel-structure of mesoporous ZnV₂O₄ as a potential novel anode for Na-ion storage and the synergetic effects of calcination temperature were studied.

Fabrication of a Z-scheme AgBr/Bi4O5Br2 nanocomposite and its high efficiency in photocatalytic N2 fixation and dye degradation

Z-scheme AgBr/Bi₄O₅Br₂ nanocomposite was synthesized via a simple ion-exchange method and firstly applied in photocatalytic N₂ fixation under simulated sunlight.

Fabrication of a Au-loaded CaFe2O4/CoAl LDH p–n junction based architecture with stoichiometric H2 & O2 generation and Cr(vi) reduction under visible light

Visible-light-efficient Au-loaded CaFe₂O₄/CoAl LDH p–n junction for H₂ & O₂ generation and Cr(vi) reduction.

Controllable fabrication of α-Ag2WO4 nanorod-clusters with superior simulated sunlight photocatalytic performance

This work presents the greatly boosted photoactivity of α-Ag₂WO₄ nanorod-clusters fabricated by adjusting the molar ratio of raw materials.

A plasmonic AuPd bimetallic nanoalloy decorated over a GO/LDH hybrid nanocomposite via a green synthesis route for robust Suzuki coupling reactions: a paradigm shift towards a sustainable future

A plasmonic AuPd bimetal-decorated GO/LDH nano-photocatalyst displays encouraging Suzuki coupling performance under visible light illumination.

Dynamics of Charge-Transfer Behavior in a Plasmon-Induced Quasi-Type-II p-n/n-n Dual Heterojunction in Ag@Ag3PO4/g-C3N4/NiFe LDH Nanocomposites for Photocatalytic Cr(VI) Reduction and Phenol Oxidation

In this work, a series of heterostructure Ag@Ag₃PO₄/g-C₃N₄/NiFe layered double hydroxide (LDH) nanocomposites were prepared by a combination of an electrostatic self-assembly and in situ photoreduction method. In this method, positively charged p-type Ag₃PO₄ was electrostatically bonded to the self-assembled negatively charged surface of the n-n-type g-C₃N₄/NiFe (CNLDH) LDH hybrid material with partial reduction of Ag⁺ to metallic Ag nanoparticles (NPs) by the photogenerated electrons and available surface -OH groups of LDH under visible light irradiation. The presence of Ag₃PO₄ as a p-type semiconductor, the surface plasmon resonance (SPR) effect of metallic Ag NPs, and oxygen vacancies as O_v-type defects in NiFe LDH could greatly achieve the quasi-type-II p-n/n-n dual heterojunctions, which was revealed by the shifted conduction band and valence band potentials in Mott-Schottky (M-S) analysis. Among all the optimized heterostructures, CNLDHAgP4 could achieve the highest photocatalytic Cr(VI) reduction rate of 97% and phenol oxidation rate of 90% in 2 h. The heterostructure CNLDHAgP4 photocatalyst possesses a unique morphology consisting of cubic phases of both Ag NPs and Ag₃PO₄, which adhered to the thin and curvy layers of the CNLDH hybrid for smooth electronic and ionic charge transport. Furthermore, the intimate Schottky barriers formed at the interface of quasi-type-II p-n/n-n dual heterojunctions were verified by the photoluminescence, linear sweep voltammetry, M-S, electrochemical impedance study, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy studies. The SPR effect of Ag NPs and oxygen vacancies as O_v-type defect in NiFe LDH can effectively accelerate the threshold of charge separation and be the main reason for the enhanced activity achieved by the as-fabricated heterostructure photocatalyst.