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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]

The possible impact of antivirals on ecosystems and the emergence of antiviral resistance are the reasons for concern about their environmental release. Consequently, there has been a significant increase in curiosity regarding their presence in both organic and synthetic systems in recent years. The primary objective of this review is to address the void of information regarding the global presence of antiviral drugs in both wastewater and natural water sources. Photocatalytic degradation of pollutants is an eco-friendly, cost-effective method that effectively addresses environmental degradation. The development of efficient photocatalysts remains a significant issue in accelerating the degradation of pollutants, especially when employing solar light. Thus, the development of Z-scheme and S-scheme semiconductor heterojunctions has emerged as a viable method to improve light absorption and enhance the redox capability of photocatalysts. The principles of Z-scheme and S-scheme are reviewed extensively. The degradation route and occurrence of antiviral are discussed briefly. Finally, a short preview of the degradation of antiviral using Z-scheme and S-scheme is also highlighted. [ABSTRACT FROM AUTHOR]

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 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]

This work focuses on enhancing the photocatalytic activity of Co1−xZnxFe2O4 (cobalt-zinc nanoferrite) via peroxymonosulfate (PMS) activation for high-performance sulfosalicylic acid (SSA) degradation. The optimal Co0.7Zn0.3Fe2O4 (C2) sample led to the best photocatalytic performance for PMS activation under visible light. The photoluminescence and electrochemical impedance measurements confirmed the higher charge separation for C2 catalyst. The radical quenching and ESR tests revealed that SO4−• and •OH radicals were the dominant reactive species with little contribution from singlet oxygen for SSA degradation. The presence of Fe3+/Fe2+ and Co3+/Co2+ redox cycles enhanced the PMS activation to a great extent. Interestingly, the hydroxyl radicals were generated via the PMS activation route and contributed to degradation. As a result, photocatalysis and PMS activation complemented one another and improved performance. The best catalyst was also tested for the photocatalytic activity coupled with PMS activation for other pollutants including bisphenol A, tetracycline, rhodamine B, and 2,4-dichlorophenol. Additionally, due to their strong ferromagnetism and stability, the ferrites can be readily isolated magnetically from treated waste water, indicating their potential application in large-scale wastewater treatment for various contaminants. [ABSTRACT FROM AUTHOR]

Constructing visible-light-active Z-scheme heterojunctions has proven fruitful in enhancing the photocatalytic activity of photocatalysts for superior water clean-up. Herein, we report the fabrication of a CoFe2O4@Bi2O3/NiO (CBN) Z-scheme nanoheterojunction. The obtained CBN heterojunction was used for visible-light-assisted degradation of ofloxacin (OFL) in water. The OFL degradation efficiency achieved by the CBN heterojunction was 95.2% in 90 min with a rate constant of kapp = 0.03316 min−1, which was about eight times that of NiO and thirty times that of CoFe2O4. The photocatalytic activity of a Bi2O3/NiO Z-scheme heterojunction was greatly enhanced by the visible activity and redox mediator effect of the cobalt ferrite co-catalyst. Higher charge-carrier separation, more visible-light capture, and the Z-scheme mechanism in the Z-scheme system were the important reasons for the high performance of CBN. The scavenging experiments suggested ●O2− as an active species for superior OFL degradation. The possible OFL degradation pathway was predicted based on LC-MS findings of degradation intermediate products. The magnetic nature of the CBN helped in the recovery of the catalyst after reuse for six cycles. This work provides new insights into designing oxide-based heterojunctions with high visible-light activity, magnetic character, and high redox capabilities for potential practical applications in environmental treatment. [ABSTRACT FROM AUTHOR]

Water pollution has been a prevalent issue globally for some time. Some pollutants are released into the water system without treatment, making the water not suitable for consumption. This problem may lead to more grave problems in the future including the destruction of the ecosystem along with the organisms inhabiting it, and illness and diseases endangering human health. Conventional methods have been implemented to remove hazardous pollutants such as dyes, heavy metals, and oil but are incapable of doing so due to economic restraints and the inability to degrade the pollutants, leading to secondary pollution. Photocatalysis is a more recently applied concept and is proven to be able to completely remove and degrade pollutants into simpler organic compounds. Titanium dioxide (TiO2) is a fine example of a photocatalyst owing to its cost-effectiveness and superb efficiency. However, issues such as the high recombination rate of photogenerated electrons along with positive holes while being only limited to UV irradiation need to be addressed. Carbonaceous materials such as graphene oxide (GO) can overcome such issues by reducing the recombination rate and providing a platform for adsorption accompanied by photocatalytic degradation of TiO2. The history and development of the synthesis of GO will be discussed, followed by the methods used for GO/TiO2 synthesis. The hybrid of GO/TiO2 as a photocatalyst has received some attention in the application of wastewater treatment due to its efficiency and it being environmentally benign. This review paper thereby aims to identify the origins of different pollutants followed by the sickness they may potentially inflict. Recent findings, including that GO/TiO2-related nanocomposites can remove pollutants from the water system, and on the photodegradation mechanism for pollutants including aromatic dyes, heavy metal and crude oil, will be briefly discussed in this review. Moreover, several crucial factors that affect the performance of photocatalysis in pollutant removal will be discussed as well. Therefore, this paper presents a critical review of recent achievements in the use of GO/TiO2-related nanocomposites and photocatalysis for removing various pollutants in wastewater treatment. [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]

[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]

Photocatalysis has established itself as a fascinating topic, giving promise for effective processing of greenhouse gases and contaminants into useful products, in the search for renewable energy sources and atmospheric rehabilitation. This review study provides a thorough examination of S-scheme heterojunction photocatalysts with an emphasis on their uses in the photocatalytic reduction of CO 2 , N 2 fixation and NO x degradation processes. The review explains various environment-related issues, the basic ideas of photocatalysis and heterojunctions, emphasizing the benefits of S-scheme topologies in increasing interfacial transmission of charges and lowering electron-hole recombination. The fundamentals and issues of photocatalytic CO 2 reduction, nitrogen fixation and NO x degradation, outlining the mechanics involved in employing S-scheme heterojunctions have been discussed. The recent advancements of S-scheme photocatalysts for a variety of applications are highlighted in this review. The future prospects of such assemblies are also critically evaluated, highlighting the importance of full use of solar spectrum, wide scale preparation of photocatalysts, maintaining the redox capability and mechanism elucidation to prepare superior S-scheme heterojunctions to resolve the important energy and environmental issues. [Display omitted] • S-scheme heterojunctions as efficient photocatalysts –Fundamentals and advantages. • Mechanisms of photocatalytic CO 2 reduction, N 2 fixation and NO x degradation. • Designing and synthesis of S-scheme heterojunction photocatalysts. • Applications for reducing CO 2 into fuels, fixation of N 2 into NH 3 and degrading NO x. [ABSTRACT FROM AUTHOR]

• g-C 3 N 4 and MOFs based heterojunctions –synthesis routes and advantages. • Types of g-C 3 N 4 and MOFs heterojunctions were discussed-modification strategies. • g-C 3 N 4 and MOFs based heterojunctions for photocatalytic environmental remediation and energy production. • Conclusion and future research prospects on g-C 3 N 4 and MOFs based on heterojunctions. Photocatalytic technology has emerged as a promising solution for environmental remediation and energy production, and the development of efficient and stable photocatalysts is of great importance. Recent advances in g-C 3 N 4 /Metal Organic Frameworks (MOFs) heterojunctions have shown excellent potential in achieving high-performance photocatalytic environmental remediation and energy production. In this review, we have summarized the recent advances in the design and synthesis of g-C 3 N 4 /MOFs heterojunctions and their application in photocatalytic environmental remediation and energy production. We have discussed the advantages and challenges of g-C 3 N 4 /MOFs heterojunctions, such as enhanced light absorption, increased surface area, and improved electron-hole separation, and their effects on photocatalytic performance. We also highlight the recent research progress in the utilization of g-C 3 N 4 /MOFs heterojunctions for various environmental remediation applications, including the degradation of organic pollutants and the removal of heavy metals, as well as for energy production applications such as hydrogen evolution and CO 2 reduction. Furthermore, we provide an overview of the latest theoretical and experimental investigations into the mechanisms of photocatalysis in g-C 3 N 4 /MOFs heterojunctions, which can help to guide the rational design of high-performance photocatalysts. Our analysis of the literature reveals that g-C 3 N 4 /MOF heterojunctions have demonstrated excellent photocatalytic activity for the degradation of various pollutants, such as methyl orange, rhodamine B, and bisphenol A. For instance, a g-C 3 N 4 /ZIF-8 heterojunction achieved a photocatalytic degradation rate of 99.9% for methyl orange under visible light irradiation within 60 min. Moreover, the g-C 3 N 4 /MOF heterojunctions have also been found to be efficient in water splitting for hydrogen production. For instance, a g-C 3 N 4 /UiO-66 heterojunction achieved a hydrogen production rate of 1260 μmol h−1g−1 under visible light irradiation. The recent data on the advances in g-C 3 N 4 /MOFs heterojunctions demonstrate their enormous potential for practical applications in photocatalytic environmental remediation and energy production. [ABSTRACT FROM AUTHOR]

In this work we report the fabrication of novel magnetic ternary PANI/LaFeO 3 /CoFe 2 O 4 (PLC) heterojunction through in situ polymerization of aniline. As fabricated photo catalyst has been characterized by using FT-IR, XRD and XPS. The surface as well as internal morphologies has been studied by SEM and TEM. The optical activities have been investigated by UV-Vis and photoluminescence spectroscopy. The synthesized catalysts were used for effective photo degradation of pharmaceutical pollutant clozapine (CZP) under visible light irradiation. In comparison with sole counterpart photo catalysts PANI, LaFeO 3 and CoFe 2 O 4 , PLC demonstrated superior photo-activity, PLC able to degrade 94.2% of CZP over 120 min photo degradation experiment. The effect of catalysts dosage, pH, SO 4 2-, NO 3 - and HCO 3 - ion on the photocatalytic activity has been explored. 37.4% and 78.3% of TOC and COD removal has been achieved for the CZP photo-degradation by PLC. The major active radical species have been identified by performing radical scavenging experiment. [Display omitted] • Ternary PANI/LaFeO 3 /CoFe 2 O 4 visible light active photo catalysts. • Charge separation and reduced electron-hole pair's recombination rate-outstanding optical activity. • Sun light assisted photo degradation of clozapine. • Mineralization is achieved in 180 min with 37.4% and 78.3% of TOC and COD removal respectively. • The photo catalysts found to be re-usable for 5 consecutive cycle. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ti3+ self-doped Ti-Bi 2 WO 6 @ACB exhibits oxygen vacancies, OFGs, and defects. • Ti-Bi 2 WO 6 @ACB efficiently degraded high concentrations of CAP and disinfection. • Ultrasound enhances photocatalytic activity related to synergistic sonocatalysis. • The Ti-doping can generate more ROS, and ACB prevents TiO 2 /Bi 2 WO 6 agglomeration. • The degradation process of CAP is recorded, and six degradation paths are possible. A novel engineered biochar (ACB)-based Ti-doped Bi 2 WO 6 composite (Ti-Bi 2 WO 6 @ACB) was synthesized via a one-step hydrothermal reaction for the efficient degradation of chloramphenicol (CAP) and extensive environmental applications. Multiple characterization techniques, CAP degradation effects, total organic carbon (TOC) removal, effects of environmental factors, recycling tests, actual wastewater treatment, enhancement strategies, and disinfection effects were systematically evaluated. It was found that Ti-Bi 2 WO 6 @ACB is a Ti3+ self-doped TiO 2 /Bi 2 WO 6 /ACB ternary heterogeneous photocatalyst. The introduction of ACB and Ti doping enhanced the elemental composition, oxygen-containing functional groups, defect structure (oxygen vacancies), visible-light absorption, and active sites. Moreover, Ti-Bi 2 WO 6 @ACB effectively inhibited the recombination of photogenerated carriers. The removal efficiency of Ti-Bi 2 WO 6 @ACB for 50 mg⋅L−1 CAP was 92.44 % at 120 min of irradiation, and the TOC removal rate was 67.72 %, which was significantly higher than that of the control treatment. Ti-Bi 2 WO 6 @ACB is reusable and photostable, with approximately 99 % sterilization of Staphylococcus aureus and Escherichia coli within 10 min of light irradiation and 48 h of cultivation. The addition of H 2 O 2 , ultrasonication, heating, and blowing air in the system improved the photocatalytic efficiency. The ultrasound enhancement mechanisms are related to the effects of cavitation, microjets, and photocatalysis coupled with sonocatalysis. CAP degradation was dominated by OH, O 2 −, and h+. The doping of Ti3+/TiO 2 generated more defects and O 2 −, and the ACB acted as a carrier to prevent the agglomeration of TiO 2 and Bi 2 WO 6. Further, the degradation process of CAP was documented and the degradation pathways may include hydroxylation addition, methanol denaturation, substitution, C–N bond breaking, oxidation, hydrolysis, and decarboxylation reactions. The research presents fresh insights into the development of high-performance engineered biochar-based composite for environmental detoxification. [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]

We report the fabrication of a novel waste-derived biochar-impregnated Bi 5 O 7 Br/Fe 3 O 4 (WBF) magnetic composite for photocatalytic removal of malachite green pollutant. The newly prepared catalyst was applied for the removal of malachite green dye under visible light irradiation. It was found that the composite degrades 99.39% MG dye within 20 min of the experiment as compared to Bi 5 O 7 Br, Fe 3 O 4, and biochar with 83.19%, 75.09%, and 55.47% in the 50-min experiment. The findings demonstrated that a photocatalytic integrated composite quickly transfers charges across surfaces and effectively separates electron-hole pairs, considerably increasing charge carrier separation and photocatalytic activity. Further, the kinetics show that the rate constant for WBF composite is 7.1 times higher than that observed for Bi 5 O 7 Br. Scavenging experiments reveal the huge role of.OH and •O 2 − radicals in malachite green degradation. Additionally, the magnetic nature of the catalyst ensures the easy separation of the catalyst during photocatlytic experiments and reduces the chance of secondary pollution. The results showed that integrating Bi 5 O 7 Br and biochar with Fe 3 O 4 to create photocatalytic composites is a very efficient strategy to boost photocatalytic activity for environmental waste water treatment. [Display omitted] • Newly designed waste derived bio-char impregnated Bi 5 O 7 Br/Fe 3 O 4 magnetic composite was successfully synthesised. • Composite degrades 99.39% MG dye within 20 min of the experiment. • Rate constant for MG removal for WBF composite is 7.1 times higher than that observed for Bi 5 O 7 Br. • Integrated composite improves the charge carrier separation and photocatalytic activity. • Composite exhibit sound stability upto six degradation cycles. [ABSTRACT FROM AUTHOR]