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In this work, we fabricated an Ag/Bi7O9I3 composite and tested the composite for the photodegradation of Rhodamine B (RhB) dye under UV–vis light irradiation. XRD, FESEM, TEM, UV–visible absorbance, XPS studies, ESR, and electrochemical analysis were used to characterize the synthesized photocatalysts. The synthesized catalyst displayed a maximum degradation efficiency of 98.45% in the 150-min experiment, which is nearly 1.56 times higher than Bi7O9I3. The enhanced photocatalytic activity of Ag/Bi7O9I3 is attributed to the acceleration of charge separation and transfer of charge carriers with the inclusion of Ag. The improvement in photocatalytic efficiency of Ag/Bi7O9I3 can be attributed to Ag deposition, which acts as an electron sink to avoid recombination of photogenerated electrons and holes. Additionally, Ag nanoparticles may show plasmonic resonance producing more electron–hole pairs in Bi7O9I3. Furthermore, a variety of tests were carried out on Ag/Bi7O9I3 in order to clarify how different factors affect the photodegradation efficiency. The medium with pH = 3, catalyst loading = 35 mg, and Rhodamine B concentration = 10 ppm resulted in highest activity. Using a radical scavenging experiment and ESR studies, the effective radicals in promoting dye degradation have been identified, and ·O2− radicals turned out to be the main radicals in promoting photocatalysis. Additionally, the reusability and degradation mechanisms of the enhanced photodegradation on the specified photocatalyst were examined. [ABSTRACT FROM AUTHOR]

In the contemporary era marked by pressing environmental and energy challenges, there is a growing imperative to create effective and eco-friendly approaches to combat pollution and promote the generation of clean and green energy. One such strategy that has attracted much interest recently is the photocatalytic generation of green energy and pollutant removal. Numerous photocatalysts have been created to treat water and generate clean energy. Zn-Ti LDH materials are two-dimensional materials that have unique physical and chemical properties, making them promising photocatalysts. Zn-Ti LDHs have a distinctive layered structure that makes them extremely adaptable for photocatalytic applications. This structure also provides large surface areas, customisable compositions, and abundant active sites. However, Zn–Ti LDH has a low solar energy efficiency because it is primarily triggered by ultraviolet light, which makes up around 5% of sunshine. Therefore, this investigation aims to provide a thorough summary of the latest advancements in the modification of the materials based on Zinc-Titanium Layered Double Hydroxides (Zn-Ti LDHs) for a broad spectrum of photocatalytic uses. This study also covers the fabrication methods for Zn-Ti LDHs and the creation of heterojunctions and composites based on Zn-Ti LDHs. Additionally, it delves into the mechanisms underlying the degradation of pollutants and the generation of clean energy. We have highlighted the potential for new prospects, existing challenges, and progress in this context. [Display omitted] • Fabrication and photocatalytic mechanisms of Zn-Ti LDH based materials for environmental solutions. • Latest advancements in heterojunctions and composites utilizing Zn-Ti LDH for applications in photocatalysis. • Various approaches for enhancing the photocatalytic capabilities of Zn-Ti LDH are explored. • The summary, challenges, and future outlook are all addressed. [ABSTRACT FROM AUTHOR]

Due to the ultra-high efficiency, environmental compatibility, structural/chemical stability, and effective usage of active metal centres, new single-atom catalysts, particularly single-atom carbon-based nano-photocatalysts, are promising "materials" for environmental remediations. Owing to their outstanding structure and features, like enormous activity, the selectivity, maximal atom usage, and improved intrinsic catalytic activity, single-atom catalyst has piqued researchers' interest. There is a wide class of carbon-based nanomaterials family which can be explored for the stabilization of single-atom catalysts. The carbon and carbon-based nanomaterials provide an excellent substrate for anchoring metal/metal oxide single-atom catalysts because of low-cost production, excellent conductivity, high surface area and functionality and tunable properties. The single-atom catalyst-based materials have found applications in electrocatalyis, hydrogen generation, carbon dioxide conversion and catalytic transformations. However, limited work has been done on utilizing carbon supported single-atom catalysts for high-performance removal/degradation of broad range of noxious organic and inorganic contaminants from water. Low coordination states, quantum size effects, and strong interactions with metals in nano-dimensions give them these features, which have proven to be particularly resilient in photocatalysis. In this paper, various methodologies for the manufacture of carbon-based single-atom catalysts are described. Then, in terms of comprehending the electrical and geometric properties of catalysts based on a single carbon atom, current developments in various characterization techniques and computer achievements were summarised. Meanwhile, aquatic pollution is being tackled using catalysts based on single carbon atom photocatalysts. The materials based on single-atom catalysts anchored/supported on to carbon materials based materials as carbon, carbon quantum dots, graphene, carbon nitride, etc. have been discussed. Finally, the prospects for their development, along with future prospects, are explored. Schematic illustration of synthesis techniques including their advantages, disadvantages and waste water remediation applications of nano-carbon matrix supported single-atom catalysts. [ABSTRACT FROM AUTHOR]

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

In the current study, g-C3N4/Fe-MOF was synthesised and utilised for the elimination of antibiotic contaminants from wastewater. There are two steps followed for the fabrication of g-C3N4/Fe-MOF i.e. pyrolysis and solvothermal method. The proximity of g-C3N4 and Fe-MOF was confirmed by X-ray diffraction, scanning electron microscopy, ultraviolet spectroscopy, electrochemical impedance spectroscopy, photoluminescence spectroscopy, and X-ray photoelectron spectroscopy analysis of as-prepared samples. The developed photocatalyst was tested for tetracycline degradation. Remarkable photocatalytic activity for tetracycline under visible light irradiation is demonstrated by the g-C3N4/Fe-MOF photocatalyst. In comparison to bare g-C3N4 and Fe-MOF, the g-C3N4/Fe-MOF (G4) demonstrates significantly stronger photocatalytic activity. The best degradation efficiency of 87.12% was achieved at optimized reaction conditions with TC concenteration-25 ppm, catalyst dosage-40 mg and pH-5.5. The enhanced photocatalytic activity is because of the direct Z-scheme heterojunction formed between g-C3N4 & Fe-MOF, which allows for easier separation of photoinduced charge. The investigation also represented an analysis of the prevailing active species and potential photocatalytic mechanism. Finally, the study concludes that the optimized nanocomposite, consisting of g-C3N4/Fe-MOF, exhibited significant biocompatibility as seen by the development of barley seeds in the resultant solution after the degradation process. [ABSTRACT FROM AUTHOR]

The fast development of urbanisation and industrialisation has led to a rise in nitrogen oxide (NO x) emissions, specifically nitric oxide (NO). One effective method for reducing the harmful effects of this dangerous air pollutant on both human health and the environment is the photocatalytic oxidation of NO. Z-scheme heterojunctions enhance incident light utilisation and increase photocatalytic activity, eventually leading to better NO oxidation performance by encouraging the effective separation of charges and migration. A comprehensive discussion of Z-scheme-based heterojunctions is provided in this review paper, with a focus on their applications in the photocatalytic oxidation of NO. Significant progress has been made in the fabrication of efficient photocatalytic devices in recent years, with Z-scheme-based heterojunctions proving to be particularly successful. The review looks into the various methodologies used to create Z-scheme-based heterojunctions as well as photocatalytic NO oxidation mechanisms. Recent studies on photocatalysts employing Z-scheme heterojunctions for the photocatalytic oxidation of NO are also discussed. The possibilities for new opportunities as well as the present challenges, barriers, advances, and solutions have been emphasized. [ABSTRACT FROM AUTHOR]

This review presents an overview of recent developments and advancements in the field of photocatalytic hydrogen evolution using poly(heptazine imide) (PHI) and based materials. Photocatalytic hydrogen evolution (PHE) has received great amount of attention because of its potential as a clean and sustainable energy source and PHI based materials have emerged as promising candidates for this purpose due to their distinct structural properties, improved light absorption, charge separation and reduced recombination. This review discusses the essential concepts of PHE and the potential of poly(heptazine imide) materials and their derivatives as photocatalysts and also the limitations of these materials in photocatalytic activity. It addresses the synthetic routes and strategies adopted to enhance the photocatalytic activity of these materials including surface modifications, band engineering, doping, loading co‐catalysts and composites & heterojunction construction. Furthermore, the recent works in photocatalytic H2 evolution using PHI and based materials have been summarized and discussed. Additionally, we examined the challenges and future outlooks in this field, emphasizing the need for scalable and cost‐effective production methods. [ABSTRACT FROM AUTHOR]

[Display omitted] • Overview of fundamentals of Nb 2 O 5 as photocatalyst-structure and properties. • Heterojunction photocatalysts -Z and S scheme- charge transfer routes. • Recent advances in Nb 2 O 5 based heterojunctions for photocatalytic applications. • Strategies for improving the photocatalytic performance Nb 2 O 5 based heterojunctions. Significant advancements in the field of photocatalysis in recent years have highlighted the heterojunctions based on Nb 2 O 5 as a focal point of research. This comprehensive review diligently analyses the progress in Nb 2 O 5 -based heterojunctions for their application in photocatalysis, focusing on synthesis, characteristics and their pivotal role in addressing crucial energy and environmental challenges. The review emphasizes the fundamental principles of photocatalysis in pollutant removal and H 2 generation, elucidating key processes such as light absorption, charge generation and surface reactions. The different types of heterojunctions, their basic principles and role in enhancing the charge separation and overall photocatlytic performance have been discussed. The recent advances in Nb 2 O 5 -based heterojunctions are extensively discussed for the photocatalytic applications such as pollutants removal and H 2 evolution. Furthermore, the review delves into strategies employed to enhance the photocatalytic activity of Nb 2 O 5 -based heterojunctions such as doping, oxygen vacancies modification, morphological engineering and atomic control, as well as loading with support materials. Each strategy is explained, emphasizing its impact on charge separation and overall efficiency. The review concludes by highlighting existing challenges and providing insights into potential future directions that integrates synthetic processes, novel methods for photoelectric characterization, and an in-depth understanding of the local structure of Nb 2 O 5. This review serves as a valuable resource for researchers in the field, offering a comprehensive overview of the state-of-the-art in Nb 2 O 5 -based heterojunctions for advanced photocatalytic applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fundamentals of phosphorene (PN) and graphdiyne (GDY) are briefly discussed. • Structure, fabrication routes and modification strategies. • Advances in PN and GDY based heterostructures for photocatalytic hydrogen evolution. • Environment stability, challenges and future perspectives. Hydrogen evolution from water splitting using semiconductor photocatalysis is regarded as a sustainable and clean energy solution. Among various new age materials, the two-dimensional (2D) monoelemental materials as graphdiyne (GDY) and phosphorene (PN) showing excellent performance owing to their 2D atomic structure and unique properties, have drawn considerable attention. Graphdiyne (GDY) is a two-dimensional carbon-based compound having sp and sp2 hybridized carbon, diacetylene linkage, triangular holes framework and customizable band gap. Different stacking arrangements and homogenous pores in GDY can produce electronic characteristics, opening the door to intriguing energy applications. On the other hand, phosphorene derived from black phosphorous (BP) exhibits strong hole mobility, a variable band gap and broad optical absorption spectrum. With a significant increase in photo-excited charge-separation efficacy, the development of heterostructured photocatalysts driven by BP/PN and GDY has recently become the subject of study in photocatalysis. The recent advancements in development of phosphorene and graphdiyne and their accompanying heterostructured photocatalysts is outlined here, along with their structure, characteristics, synthetic routes and photocatalytic applications. In addition, the photocatalytic applications of PN and GDY based composites and heterostructures have been reviewed and summarised for photocatalytic hydrogen evolution through water splitting. Environmental stability of these heterostructured photocatalysts and the difficulties they pose have been thoroughly investigated for their more effective and extensive uses in the future. [ABSTRACT FROM AUTHOR]

Pollution and the rising energy demand are two major society issues, requiring urgent solutions. Here, we review the simultaneous production of hydrogen and removal of pollutants, with a focus on mechanisms, synthesis of photocatalysts, and applications. Remarkably, this method utilizes organic pollutants as sacrificial agents for photocatalytic hydrogen production, thus both reducing pollution and producing energy. Metal-doped, cocatalyst-loaded, organic and inorganic composite, heterostructure and heterojunction photocatalysts are described. We present applications to the removal of antibiotics and organic dyes. Pollutant degradation rates range from 5.3 to 100%, with hydrogen evolution of 13.7–2724.89 μmol·g–1h–1. [ABSTRACT FROM AUTHOR]

In pursuit of advancing photocatalysts for superior performance in water treatment and clean energy generation, researchers are increasingly focusing on layered double hydroxides (LDHs) which have garnered significant attention due to their customizable properties, morphologies, distinctive 2D layered structure and flexible options for modifying anions and cations. No review has previously delved specifically into ZnCr and NiCr LDH-based photocatalysts and therefore, this review highlights the recent surge in ZnCr and NiCr-based LDHs as potential photocatalysts for their applications in water purification and renewable energy generation. The structural and fundamental characteristics of layered double hydroxides and especially ZnCr-LDHs and NiCr-LDHs are outlined. Further, the various synthesis techniques for the preparation of ZnCr-LDHs, NiCr-LDHs and their composite and heterostructure materials have been briefly discussed. The applicability of ZnCr-LDH and NiCr-LDH based photocatalysts in tackling significant issues in water treatment and sustainable energy generation is the main emphasis of this review. It focuses on photocatalytic degradation of organic pollutants in wastewater, elucidating the principles and advancements for enhancing the efficiency of these materials. It also explores their role in H 2 production through water splitting, conversion of CO 2 into valuable fuels and NH 3 synthesis from N 2 , shedding light on their potential for clean energy solutions. The insights presented herein offer valuable guidance for researchers working towards sustainable solutions for environmental remediation and renewable energy generation. [Display omitted] • Fundamentals and properties of Layered Double Hydroxides (LDHs). • ZnCr and NiCr LDHs as photocatalysts-Properties and Performance. • Water treatment and clean energy production-Mechanism and issues. • ZnCr and NiCr LDH based water treatment & clean energy production. • The challenges and future development direction for sustainable use are discussed. [ABSTRACT FROM AUTHOR]

Microplastics (MPs), as emerging pollutants, have attracted the attention of environmentalists, statespersons, and the scientific community over the last few decades. To address the spread of MPs in the environment, it is imperative to develop various removal techniques and materials that are effective, scalable, and ecologically benign. However, to the best of our knowledge, no review has systematically examined the removal of MPs using adsorption or provided an in-depth discussion on various adsorbents. Adsorption is an inexpensive and effective technology for wastewater treatment. Recently, many researchers have conducted studies on MP remediation using diverse adsorbent materials, such as biochar, activated carbon, sponges, carbon nanotubes, metal-layered oxides, metal-organic frameworks (MOFs), and zeolites. Each adsorbent has advantages and disadvantages. To overcome their disadvantages, researchers have been designing and developing hybrid adsorbents for MP remediation. This review provides insights into these individual adsorbents and also discusses hybrid adsorbents for MP removal. Finally, the review elaborates on future possibilities and ways to enable more efficient, scalable, and environmentally friendly MP cleanup. Overall, this review bridges the gap between contemporary MP remediation using adsorption techniques and adsorbent development. [Display omitted] • Adsorption-based microplastic remediation was reviewed. • The factors affecting microplastic adsorption were thoroughly discussed. • A comprehensive analysis is presented on several microplastic adsorbents. • Microplastic adsorption challenges and future perspectives are examined. [ABSTRACT FROM AUTHOR]

[Display omitted] • Oxygen vacancies fundamentals and importance in photocatalysis. • Oxygen vacancies rich heterojunction-Synthetic strategies. • OVs rich Z-scheme and S-scheme heterojunctions- Photocatalytic mechanism. • Applications for Hydrogen production and water treatment. • The existing challenges and future perspectives. Photocatalytic removal of pollutants and energy production is a green, low cost and environment friendly technology for addressing the mounting pressure of energy crisis and environmental deterioration. Developing efficient photocatalysts is still a big challenge for accelerating the photocatalytic hydrogen production and pollutant degradation especially utilizing solar light. Therefore, constructing oxygen vacancies rich Z-scheme and S-scheme semiconductor heterojunctions emerged as a promising approach to enhance the light harvesting and increasing the redox capability of photocatalysts. This review comprehensively summarises the state of art focus on oxygen vacancy's role in photocatalysts especially in Z-scheme and S-scheme heterojunctions including synthesis process and modifications. In particular, the functions of oxygen vacancy in supporting the main processes in photocatalytic energy production and pollutant removal, such as light absorption, charge separation and conversion are highlighted in this review. The current issues and future prospective in oxygen vacancies rich heterojunctions for efficient photocatalytic removal of pollutant and energy production are also addressed. Finally, a brief discussion on challenges and future prospects is demonstrated. [ABSTRACT FROM AUTHOR]

Pectin-crosslinked gum ghatti hydrogel (PGH) has been synthesized utilizing pectin and gum ghatti through an uncomplicated and inexpensive copolymerization method. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM-elemental mapping), Brunauer-Emmett-Teller (BET), and X-ray photoelectron spectroscopy (XPS) characterization techniques have been employed to determine various structural, chemical and compositional characteristics of fabricated PGH. Three different weight ratios (1:1, 2:1, or 1:2 for pectin and gum ghatti, respectively) were employed to synthesize three distinct types of PGH. Swelling studies has been done to determine the best ratios for PGH fabrication. PGH has been assessed as an adsorbent for the removal of malachite green dye from aqueous solutions. The effects of PGH dosage (100–400 mg/L), dye concentration (10–160 mg/L), pH (2–9 pH), adsorption time (0–480 min), and temperature (25–55 °C) has been examined through batch solutions. According to Langmuir isotherm analysis, the maximum adsorption capacity is 658.1 mg/g. By using pseudo-second-order kinetics and the Freundlich adsorption isotherm, the adsorption process could be well explained. After five consecutive cycles, PGH had an adsorption percentage of 86.917 % for the malachite green dye. It is safe for the environment and may be used to remove malachite green (MG) dye from aqueous solutions. [Display omitted] • Pectin-crosslinked gum ghatti hydrogel (PGH) synthesis using copolymerization • Study of physicochemical properties of PGH • PGH effectively adsorbed malachite green (MG) dye. • Showing a maximum capacity of 658.1 mg/g according to Langmuir isotherm analysis • Freundlich isotherm model fits well, indicating a heterogeneous adsorption process. [ABSTRACT FROM AUTHOR]

The population explosion and rapid economic development has led to tremendous increase in the per capita use of fossil fuel energy resulting in major environmental consequences. To tackle these significant energy and environmental concerns, semiconductor photocatalysis is viewed as a promising environmentally friendly and sustainable solution. The photocatalytic hydrogen evolution utilizes solar energy into clean hydrogen energy which makes it green, environmentally friendly and effective technique to meet energy demands. This process requires workable catalysts to reach a significant reaction rate because of their multiple electrons and multiple proton nature. Among various visible light active photocatalytic materials, metal molybdates have been reported as emerging class of materials owing to their outstanding features as stable crystal structure, photo-corrosion inhibition, high redox efficiency, low cost and toxicity and suitable band structure. The present research provides an extensive review of the most recent advances and new insights into the utilization of metal molybdates in photocatalytic clean energy production and environment challenges. This review article summarizes the recent progresses in advanced strategies applied in metal molybdate based photocatalysts to enhance the photocatalytic performance. The advanced strategies are categorized as control over morphology and surface modification, doping of heteroatom, co-catalyst loading, noble metal deposition and construction of heterojunction, which are devoted to photocatalytic H 2 production and CO 2 reduction and to overcome the fast recombination of charge carriers and increasing the light absorption capacity. The fabrication strategies of metal molybdates and based materials are discussed in detail, as well as their usage as catalysts for H 2 evolution and CO 2 reduction have been analysed. Metal molybdates are promising photocatalysts for addressing present environmental issues, and this work paves the way for future photocatalytic research and development, which may assist in the development of highly effective photocatalysts for sustainable energy needs. [Display omitted] • Metal molybdates as photocatalysts-Structure and properties. • Introduced the synthetic routes: Effect on properties and photocatalytic performance. • Discussed strategies to improve the photocatalytic potential of metal molybdates. • Application for superior hydrogen evolution and CO 2 conversion-Recent advances. • Fundamentals and bottlenecks along with future prospects are discussed. [ABSTRACT FROM AUTHOR]