Hydrogen, with its high energy efficiency, could generate electricity without carbon dioxide emissions, making it an ideal solution to replace fossil fuels. Water splitting, supported by catalysts, is a promising pathway for industrial hydrogen production due to its straightforward process and net-zero emissions. Hence, developing strategies to identify high-performance hydrogen evolution reaction (HER) electrocatalysts is essential in addressing energy and environmental issues. In this context, various strategies for molybdenum nitride-based heterostructures (MNHs) have been explored to improve HER efficiency. In this review, we present the HER mechanism along with theoretical aspects, followed by valuable recommendations for reliably reporting critical factors of HER electrocatalysts. Next, common crystal structures, unique properties, and synthetic approaches of molybdenum nitrides are introduced. The advantages and disadvantages of using molybdenum nitrides for HER are also presented. More importantly, various strategies for MNHs, including morphology engineering, combined with carbon materials and doping engineering, are discussed for HER. Moreover, recent works based on MNHs for water splitting at large current densities are presented, evaluating industrial application possibilities. Finally, the remaining challenges and prospects for advancing MNHs for hydrogen production are discussed.

The exploration of high-efficiency electrodes for alkaline water electrolysis is significant in the advancement of hydrogen energy, minimizing the influence of CO2 emission to the environment. Ni-based materials have been evaluated as potential electrocatalysts for hydrogen evolution reaction (HER) because of their promising catalytic activities, low cost, and remarkable durability. In this work, we synthesized a Ni-based metal-organic framework on carbon fiber (CF) through the hydrothermal method, followed by pyrolysis to create Ni metal particles implanted on carbon frameworks (Ni/C/CF). The Ni/C/CF catalyst displayed a higher catalytic efficiency than Ni/C powder. The Ni/C/CF electrode needs an overpotential of 117 mV to achieve 10 mA cm-2 and remarkable durability, which was confirmed by 2000 cycles and 12 h of continuous hydrogen production. This performance was attributed to the effectiveness of CF with a three-dimensional structure, favoring more exposed active sites and efficient electron transport. Moreover, carbon frameworks, inherited from MOF materials, preserve catalytic sites and avoid the aggregation of Ni nanoparticles, maximizing active sites for HER. The results of this work could bring a potential direction for the preparation of transition metal-based materials on CF as efficient non-binder electrodes for HER. Direct synthesis of Ni-MOF-74 on the surface of carbon fiber was achieved.Carbon fiber enhances electrochemical surface area and charge transport properties of Ni/C/CFCarbon skeleton protected and improved active sites for HER.Ni/C/CF binder-free cathode requires only 117 mV to obtain 10 mA cm-2.Ni/C/CF cathode displayed an outstanding stability in alkaline solution.

Humification offers a promising avenue for sequestering dissolved organic carbon while facilitating environmental cleanup. In this study, CuMgFe layered double oxides (LDO) were applied as a catalyst to replace conventional enzymes, such as laccase, thereby enhancing the in vitro polyphenol-Maillard humification reaction. CuMgFe LDO was synthesized through calcination of CuMgFe layered double hydroxides (LDH) at 500 °C for 5 h. A suite of characterization methods confirmed the successful formation into mixed oxides (Cu2O, CuO, MgO, FeO, and Fe2O3) after thermal treatment. A rapid humification reaction was observed with CuMgFe LDO, occurring within a two-week span, likely due to a distinct synergy between copper and iron elements. Subsequent analyses identified that MgO in CuMgFe LDO also played a pivotal role in humification by stabilizing the pH of the reaction. In the absence of magnesium, LDO's humification activity was more pronounced in the early stages of the reaction, but it rapidly diminished as the reaction progressed. The efficiency of CuMgFe LDO was heightened at elevated temperatures (35 °C), while light conditions manifested a discernible effect, with a modest decrease in humification efficacy under indoor light exposure. CuMgFe LDO surpassed both laccase and MgFe LDH in performance, boasting a superior humification efficiency relative to its precursor, CuMgFe LDH. The catalysts' humification activity was modulated by their crystallinity and valence dynamics. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) results suggested that introducing the amino acid, glycine, expedited the CuMgFe LDO-fueled humification, enhancing the formation of C–N and C–C bonds in the resultant products. The humic-like substances derived from the catalyst-enhanced reaction displayed an elevated presence of aromatic configurations and a richer array of oxygen functional groups in comparison to a typical commercial humic material.

A new method utilizing fluorescent ratiometry is proposed for detecting putrescine and spermidine. The method involves the use of a fluorescent probe comprising a 2D halide perovskite synthesized from octadecylamine-iodine and PbI(2)via a grinding-sonicating technique, along with a Eu3+-complex. Upon excitation at 290 nm, the probe fluoresces at two distinguishable wavelengths. The addition of putrescine and spermidine significantly decreases the emission of the 2D halide perovskite at 496 nm, while the emission of the Eu3+-complex at 618 nm remains stable. The color changes of the probe depend on the concentration of putrescine and spermidine, and the assay offers linearity over a wide concentration range (30-4000 ng mL(-1)), a low detection limit (4 ng mL(-1) for putrescine, and 7 ng mL(-1) for spermidine), and a quick response time. Furthermore, a portable device based on a smartphone can be used to record the color change of the paper test strip using the prepared fluorescent materials. The fluorescence quenching mechanism of the probe is explained as dynamic quenching.

A newly developed spherical boehmite and melamine composite with a mesoporous structure was successfully fabricated through a spray drying system utilizing a mixture of boehmite sol and melamine. EDX–SEM, FTIR, and TGA analyses confirmed the integration of melamine into the boehmite network within the resulting composite. With an increase in melamine content, the composites exhibited a gradual reduction in porosity compared to their pristine boehmite counterpart. However, the CO2 uptake of the composites continued to demonstrate improvement. The boehmite sample modified with 5 mol

This research has progressed to an effective detection chemosensor of zinc, aluminum ions and oxytetracycline hydrochloride antibiotic based on the fluorescence technique. A straightforward method utilizing microwave irradiation was employed to synthesize the salen-type Schiff base ligand N,N'-bis(salicylaldehyde)4,5-dichloro-1,2-phenylenediamine (H2I), providing a good 70 % yield. In ethanol, the H2I sensor demonstrated remarkable rapidity, selectivity, and sensitivity in detecting zinc ions. The fluorescence spectrum exhibited a 44-fold substantial enhancement at 522 nm and achieved a low limit of detection (LOD) of 1.47 μM. Furthermore, the H2I probe's emission intensity increased by 124 times when compared to the ligand's ability to detect Al3+ ions at 494 nm with a LOD value of 7.4 μM. Additional research was done using the H2I probe's effective Zn2+ detection capability. The ability to recognize zinc ions in different real water samples demonstrated a recovery rate of 98.67 % to 103.31 %. Interestingly, a naked-eye visible fluorescence color of H2I solution impregnated filter papers turned colorless into yell ow under UV irradiation by adding Zn2+ ions, renders it suitable for developing a practical zinc ion detection kit test. In particular, the I-Zn2+ complex effectively quenched the fluorescence toward oxytetracycline hydrochloride (OTC) with a LOD value of 1.49×10-2 μM in DMSO:H2O (6 : 4, v/v). This is a novel and effective procedure for sensing OTC antibiotic by the I-Zn2+ complex. These findings hold immense potential for the development of dual fluorescent probes, thereby enhancing sensitivity and specificity in identifying metal ions and antibiotics in a wide range of applications.

Conventional water treatment processes often fail to effectively remove antibacterial drugs, necessitating advanced strategies. This study presents the synthesis of novel floating, visible light-active α-NiMoO4/mpg-C3N4/EP composites for the removal of ciprofloxacin (CFX), a widely used quinolone antibiotic, from water. These composites are easily recoverable, highly stable, and demonstrate excellent reusability. The optimal photocatalyst, NC-101/EP (α-NiMoO4/mpg-C3N4 = 10:1), achieved 96.2 ± 1.1% degradation of CFX at 1.6 g L-1 within 80 minutes under visible light, significantly outperforming previous benchmarks. This high efficiency is attributed to the formation of interfacial junctions and a built-in electric field, which enhanced charge transfer and hydroxyl radical generation through an S-scheme mechanism. Fluorescence spectroscopy provided precise monitoring of CFX degradation without interference from coexisting intermediates. Density functional theory (DFT) calculations revealed that hydroxyl radicals initiated highly favorable and spontaneous oxidation of CFX, with a reaction rate constant of 6.04 × 109 M-1 s-1. The preferred oxidation pathway followed the sequence: HO-addition > H-abstraction > single electron transfer. Four degradation pathways were identified, with key intermediates confirmed by high-resolution mass spectrometry. The process also significantly reduced CFX toxicity, ensuring minimal environmental impact. These findings position NC-101/EP as a promising photocatalyst for large-scale water treatment applications targeting antibiotic contamination.

A facile approach was employed to fabricate MIL-100(Fe) materials from Fe2O3 nanoparticles through a conventional hydrothermal reaction without the presence of HF and HNO3. Effects of trimesic acid content in the reaction system on the quality and CO2/N2 separation performance of the as-prepared MIL-100(Fe) samples were investigated. Using 1.80 g of trimesic acid in the reaction system yielded the sample M-100Fe@Fe2O3#1.80, which proved to be the optimal sample. This choice struck a balance between the amount of required trimesic acid and the quality of the resulting material, resulting in a high yield of 81% and an impressive BET surface area of 1365.4 m2·g−1. At 25 °C and 1 bar, M-100Fe@Fe2O3#1.80 showed a CO2 adsorption capacity of 1.10 mmol·g−1 and an IAST-predicted CO2/N2 selectivity of 18, outperforming conventional adsorbents in CO2/N2 separation. Importantly, this route opens a new approach to utilizing Fe2O3-based waste materials from the iron and steel industry in manufacturing Fe-based MIL-100 materials.

Exploring larger surface area electrode materials is crucial for the development of efficient supercapacitors (SCs) with superior electrochemical performance.

An optical sensor based on fluorescence quenching has been developed for detecting Quercetin and Rutin. The signal source for this sensor is a hybrid organic-inorganic lead-free copper halide perovskite material, OA3Cu2I4Cl (OACuH), synthesized from octadecylamine C 18 H 39 N (OA), CuI, and CuCl. When excited at a wavelength of 355 nm, the resulting material exhibits stability and emits bright light. Characterization of the synthesized material was conducted using various methods including as X-ray powder diffraction, Fourier transform infrared (FT-IR) spectra, X-ray photoelectron spectroscopy (XPS), and fluorescent analysis. Addition of Quercetin and Rutin to OACuH resulted in a reduction in its fluorescence. The proposed sensor demonstrates excellent selectivity and a low limit of detection (70 nM for quercetin and 50 nM for rutin) within the range of 0.1-200 mu M. The reliability of the proposed assay was validated by quantifying Rutin and Quercetin in fruit samples.

Despite the keen interest in potentially using the metal-organic framework (MOF) in advanced oxidation processes (AOPs), their application for environmental abatement and the corresponding degradation mechanisms have remained largely elusive. This study explores the use of cobalt-based MOF (CoMOF) for peroxymonosulfate (PMS) activation to remove tetracycline (TC) from water resources. Under optimal conditions, the given catalytic system could achieve a TC removal of 83.3%. Radical quenching tests and EPR analysis revealed that SO4•-, HO•, •O2-, and 1O2 could participate in the catalytic degradation, but the discernible removal mechanism was mainly ascribed to the nonradical pathway induced by 1O2. At only 5 mg/L of CoMOF, the performance of the catalytic system was superior to that of PMS alone for different types of micropollutants. The CoMOF/PMS system could also reliably deal with typical anions in water, such as Cl-, SO42-, HCO3-, and PO43-. The MOF catalyst could last for four cycles with a minor decrease in reactivity of ∼30%. However, the removal performance decreased markedly when aromatic natural organic matter (NOM) were present in the water bodies, and the effectiveness was lower in alkaline or acidic environments. Our work offers insights into the catalytic degradation of CoMOF/PMS applied in contaminated water remediation and serves as a baseline for fabricating an efficient MOF with enhanced catalytic performance and stability.

Electrocatalytic water dissociation consists of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is an efficient process to create valuable fuels. But the slow OER reaction kinetics attributed to the multiple proton-coupled electron transport reaction and a high theoretical potential to a big challenge in industrial application. Hollow structures of cobalt-based electrocatalysts were considered a promising solution because of their inexpensiveness, low toxicity, large surface area, abundant exposed active sites, and adjustable elemental components. Also, hollow architectures could be used as ideal platforms for coating electrocatalysts to create beneficial effects. This study presented various strategies for generating hollow electrocatalysts, including template-assisted and template-free campaigns. Also, we summarized recent studies of Co-based electrocatalyst's hollow architectures for water splitting, which involves cobalt oxides, cobalt phosphides, cobalt selenides, cobalt sulfides, and cobalt-layered double hydroxides. Finally, the challenges and application prospects of hollow structural electrocatalysts for water dissociation are discussed.

The construction of uniform nanostructure with larger surface area electrodes is a huge challenge for the high-value added energy storage application. Herein, we demonstrates ZIF67@ZIF8 (core-shell) and ZIF8@ZIF67 (reverse core-shell) nanostructures using a low-cost wet chemical route and used them as supercapacitors. Pristine ZIF-67 and ZIF-8 was used as reference electrodes. Benefiting from the synergistic effect between the ZIF8 and ZIF67, the ZIF8@ZIF67 exhibited the outstanding electrochemical consequences owing to its larger surface area with uniform hexagonal morphology. As optimized ZIF8@ZIF67 nanostructure displayed the high-capacity of 1521 F/g at 1 A/g of current density in a three-electrode assembly in 1 M KOH electrolyte compared with other as-fabricated electrodes. In addition, the ZIF8@ZIF67 nanostructure employed into the symmetric supercapacitors (SSCs) with 1 M KOH electrolyte in two-electrode setup and it exhibited still superior output including capacity (249.8 F/g at 1 A/g), remarkable repeatability (87 % over 10,000 GCD cycles) along with high energy and power density (61.2 Wh/kg & 1260 W/kg). The present study uncovers the relationship between the larger surface area and electrocatalyst performance, supporting an effective approach to prepare favorable materials for enhanced capacity, extended lifespan, and energy density.

The quest for economical and sustainable electrocatalysts to facilitate the hydrogen evolution reaction (HER) is paramount in addressing the pressing challenges associated with carbon dioxide emissions. Molybdenum carbide-based nanomaterials have emerged as highly promising electrocatalysts for HER due to their Pt-like catalytic proficiency, exceptional stability, and the versatility of their crystal phases. Within this comprehensive review, we explore the diverse methodologies for synthesizing molybdenum carbides, including solid-gas, solid-solid, and solid-liquid phase reactions. In addition, a thorough elucidation of the hydrogen generation process through water electrolysis is provided. Furthermore, a spectrum of innovative strategies aimed at augmenting the performance of molybdenum carbides in the HER milieu is introduced, encompassing cutting-edge techniques such as phase-transition engineering, the construction of heterostructures, hetero-atom doping, the integration of hybrid structures with carbon materials, defect engineering, and meticulous surface modification. The review culminates by underscoring the current challenges and the promising prospects in the advancement of electrocatalysts for hydrogen production, with a dedicated focus on molybdenum carbide-based catalysts.

Environmental pollution, such as water contamination, is a critical issue that must be absolutely addressed. Here, three different morphologies of tungsten-based photocatalysts (WO3 nanorods, WO3/WS2 nanobricks, WO3/WS2 nanorods) are made using a simple hydrothermal method by changing the solvents (H2O, DMF, aqueous HCl solution). The as-prepared nanocatalysts have excellent thermal stability, large porosity, and high hydrophilicity. The results show all materials have good photocatalytic activity in aqueous media, with WO3/WS2 nanorods (NRs) having the best activity in the photodegradation of bisphenol A (BPA) under visible-light irradiation. This may originate from increased migration of charge carriers and effective prevention of electron‒hole recombination in WO3/WS2 NRs, whereby this photocatalyst is able to generate more reactive •OH and •O2- species, leading to greater photocatalytic activity. About 99.6% of BPA is photodegraded within 60 min when using 1.5 g/L WO3/WS2 NRs and 5.0 mg/L BPA at pH 7.0. Additionally, the optimal conditions (pH, catalyst dosage, initial BPA concentration) for WO3/WS2 NRs are also elaborately investigated. These rod-like heterostructures are expressed as potential catalysts with excellent photostability, efficient reusability, and highly active effectivity in different types of water. In particular, the removal efficiency of BPA by WO3/WS2 NRs reduces by only 1.5% after five recycling runs and even reaches 89.1% in contaminated lake water. This study provides promising insights for the nearly complete removal of BPA from wastewater or different water resources, which is advantageous to various applications in environmental remediation.

Water electrolysis in association with electrocatalysts, has been indicated as a pivotal pathway to produce hydrogen and could tackle the issues related to the carbon footprint. Co3O4-based hybrid structural materials with high catalytic activity and rich defects are evaluated as efficacious advocates of water splitting. This account commences by explicating the mechanistic underpinnings of the hydrogen evolution reaction (HER). Next, a range of hybrid structures of Co3O4 with metals, metal oxides, metal sulfides, metal phosphides, metal selenides, layered double hydroxides, and carbon materials are introduced as potential catalysts for HER. Finally, burdensome tasks and reliable guidelines for the progression of Co3O4-based architectures for the enhancement of HER are discussed.

Integrating algae into constructed wetlands (CWs) enhances wastewater treatment, although the results vary. This review evaluates the role of algae in CWs and the performance of different algae-CW (A-CW) configurations based on literature and meta-analysis. Algae considerably improve N removal, although their impact on other parameters varies. Statistical analysis revealed that 70 % of studies report improved treatment efficiencies with A-CWs, achieving average removal rates of 75 % for chemical oxygen demand (COD), 74 % for total nitrogen and ammonium nitrogen, and 79 % for total phosphorus (TP). This review identifies hydraulic retention times, which average 3.1 days, and their varied impact on treatment efficacy. Mixed-effects models showed a slight increase in COD and TP removal efficiencies of 0.6 % every ten days in the A-CWs. Future research should focus on robust experimental designs, adequate algal storage and separation techniques, and advanced modeling to optimize the treatment potential of algae in CWs.

The urgent development of economically practical and sustainable electrocatalysts to accelerate the hydrogen evolution reaction (HER) is critical for solving the pressing issues related to carbon dioxide emissions. Because of their platinum-like catalytic efficiency, excellent stability, and multidimensional structure of their crystal phases, molybdenum phosphides have emerged as extremely promising HER electrocatalysts. In this account, we begin with a meticulous explication of the hydrogen-generating process by water electrolysis, followed by an examination of the criteria used to assess HER catalytic activity. Also, the role of the phosphorus component and synthetic routes of molybdenum phosphides is presented in HER applications. Moreover, in recent years, various strategies designed to enhance the HER performance of molybdenum phosphides have been introduced, encompassing state-of-the-art techniques such as the fabrication of heterostructures, hetero-atom doping, hybrid structures involving carbon materials, and defect engineering. Furthermore, the theoretical studies based on density functional theory (DFT) are mentioned for HER. The paper concludes by emphasizing the current challenges and auspicious prospects in advancing electrocatalysts for hydrogen production, with a dedicated focus on catalysts based on molybdenum phosphides.

This study investigates ZnO/TiO2 nanocomposites synthesized by the sol-gel method for their potential application in textile wastewater treatment. The physicochemical properties of these materials were comprehensively characterized using various analytical techniques, including transmission electron microscopy (TEM), x-ray diffraction (XRD) analysis, x-ray fluorescence (XRF) spectroscopy, Brunauer-Emmett-Teller (BET) surface area analysis, and UV-visible (UV-Vis) spectroscopy. XRD and XRF analyses confirmed the formation of a ZnO/TiO2 heterostructure. TEM images revealed a quasi-spherical morphology with slight agglomeration. The ZnO/TiO2 nanocomposite with a 1:5 molar ratio of Zn(II):Ti(IV) showed the highest BET surface area (91.345 m(2) g(-1)) and the narrowest band gap (Eg = 3.06 eV). This composite demonstrated efficient degradation of methylene blue dye under sunlight irradiation and exhibited 100% antibacterial activity against S. typhi and S. aureus at concentrations >= 5 mg ml(-1), indicating its potential for treating textile wastewater.

Metal-organic frameworks (MOFs) have emerged as a key focus in water treatment and monitoring due to their unique structural features, including extensive surface area, customizable porosity, reversible adsorption, and high catalytic efficiency. While numerous reviews have discussed MOFs in environmental remediation, this review specifically addresses recent advancements in modifying MOFs to enhance their effectiveness in water purification and monitoring. It underscores their roles as adsorbents, photocatalysts, and in luminescent and electrochemical sensing. Advancements such as pore modification, defect engineering, and functionalization, combined synergistically with advanced materials, have led to the development of recyclable MOF-based nano-adsorbents, Z-scheme photocatalytic systems, nanocomposites, and hybrid materials. These innovations have broadened the spectrum of removable contaminants and improved material recyclability. Additionally, this review delves into the creation of multifunctional MOF materials, the development of robust MOF variants, and the simplification of synthesis methods, marking significant progress in MOF sensor technology. Furthermore, the review addresses current challenges in this field and proposes potential future research directions and practical applications. The growing research interest in MOFs underscores the need for an updated synthesis of knowledge in this area, focusing on both current challenges and future opportunities in water remediation.