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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]

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]

In recent times cost-effective advanced materials with dual applications in photocatalytic water treatment and electrochemical sensing have been explored and developed. Herein we report facile solution combustion synthesis of ZnO/Fe 2 O 3 (ZF) type-II heterojunction for electrochemical sensing of dopamine and visible assisted photocatalytic reduction of carcinogenic Cr(VI) into Cr(III). Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to evaluate the compatibility of the electrodes for DA sensing. Furthermore, DPV curves revealed that ZF2 (ZnO: Fe 2 O 3 - 3:0.5) modified GCEs possessed 0.27 μM and 0.7 μM of LOD and LOQ with good linear range from 3 μM to 30 μM. Overall, reproducibility and interference studies confirm the efficient use of material for DA sensing. The junction ZF2 shows best performance with 88% Cr(VI) photo-reduction under visible light in 90 min and 100% reduction with tartaric acid as sacrificial agent (utilizing holes) in just 45 min. The effect of sacrificial agents and scavengers suggest the photogenerated electrons were major active species followed by ●O 2 −. The CB edges have enough potential for rapid reduction of hexavalent chromium under visible light and solar light. The photoluminescence and electrochemical impedance suggest lowered recombination, high charge separation and charge transfer capacity in the heterojunction. The transfer of electrons from conduction band of Fe 2 O 3 to that of ZnO having high enough negative potential to reduce Cr(VI), thus utilizing the CB potential of wide band gap ZnO for rapid visible photocatalysis. In addition shortcomings as low conductivity Fe 2 O 3 and high band gap of ZnO are both minimized in the junction. This study confirmed that popular semiconductors as ZnO and Fe 2 O 3 have enough potential in dual role as electrochemical sensors and visible photocatalysts with best performance by optimizing the conditions and ratios. Image 1 [ABSTRACT FROM AUTHOR]

In the present work, mixed-spinel ferrite anchored onto graphitic carbon nitride (GCN) was synthesized for mineralization of antibiotic pollutant from waste water. A Z-scheme g-C 3 N 4 /Ni 0.5 Zn 0.5 Fe 2 O 4 nano heterojunction was fabricated by three step procedure: pyrolysis, solution combustion and mechanical grinding followed by annealing. The prepared photocatlyst was tested for degradation of Doxycycline (DC) drug under the natural sun light. Results revealed that the prepared heterojunction has maximum degradation efficiency of 97.10% pollutant in 60 min experiment. The Z-scheme heterojunction between g-C 3 N 4 and Ni–Zn ferrite improves the photoinduced charges separation and protection of redox capability and therby increases the photo degradation efficiency. The scavenging experiments suggested that O 2 −● and h+ as main active species responsible for degradation of the antibiotic. In addition, the dopant variation can drive the shists in band gap and energy band positiong too which makes then excellent candidates for synthesizing tunable heterostructures with organic semiconductors. The work focusses on designing and developing of saimpler but efficient magnetic heterojunctions with superior redox capability for solar powered waste water treatment. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • AgFeO 2 -Bi 5 O 7 I S-type heterojunctions developed by facile route. • AgFeO 2 -Bi 5 O 7 I exhibit superior 98.2 % norfloxacin degradation in120 min. • Rapid charge transfer and minimum recombination via S-scheme mechanism and oxygen-vacancies. • ●OH and ●O 2 – radicals as major reactive species- ESR findings. • Superior performance in solar light as well in different water matrices. Developing highly efficient heterojunction photocatalysts for high performance antibiotic removal is of immense importance but still remains a challenge. Herein, AgFeO 2 -Bi 5 O 7 I (AF-BI), a promising oxygen vacancies rich binary S-scheme heterojunction photocatalyst was synthseized via co-precipitation and hydrothermal treatment. The spherical AgFeO 2 spheres were uniformly affixed on the nanorods of Bi 5 O 7 I via an intimate contact, as verified through electron microscopy. The photodegradation efficiency of optimized 15 %AgFeO 2 -Bi 5 O 7 I (15AF-BI) for norfloxacin (NFX) was 98.2 % (120 min) with apparent rate constant 0.022 min−1 which was 4 times pure AgFeO 2. In municipal water, removal efficiency reached 90.4 % and a high 76.1 % and 65.2 % total organic carbon removal in 3 h in visible light and solar light respectively was achieved. The coupling of AgFeO 2 and Bi 5 O 7 I triggers electron transfer, forming an internal electric field (leading to a directional charge transfer efficient separation of the photo-induced carriers as confirmed by PL, EIS, TPCR results. The validation of existence of S-scheme mechanism and oxygen vacancies was achieved by in-situ X-ray photoelectron spectroscopy (XPS) and EPR analysis. The free radical scavenging experiments and electron spin resonance (ESR) spectroscopy revealed ●OH and ●O 2 – radicals were the major reactive species involved in the photodegradation process. The heterojunction is magnetic and can be separated under guidance of magnetic field which makes reusability and separation easy. Based on ESR findings, band structure analysis and mass spectrometry NFX degradation route was predicted. This work provides effective potential solution for preparing new magnetic S-scheme heterojunctions for effective antibiotics degradation and further will expand to realm of clean energy storage and conversion. [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]

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]

The dramatic rise in carbon dioxide levels in the atmosphere caused by the continuous use of carbon fuels continues to have a significant impact on environmental degradation and the disappearance of energy reserves. Past few years have seen a significant increase in the interest in photocatalytic carbon dioxide reduction because of its ability to lower CO 2 releases from the burning of fossil fuels while also producing fuels and important chemical products. Because of their excellent catalytic efficiency, great uniformity, lengthy charge diffusion layers and texture flexibility that enable accurate band gap and band line optimization, perovskite-based nanomaterials are perhaps the most advantageous among the numerous semiconductors proficient in accelerating CO 2 conversion under visible light. Firstly, a brief insight into photocatalytic CO 2 conversion mechanism and structural features of perovskites are discussed. Further the classification and selection of perovskites for Z and S-scheme heterojunctions and their role in photocatalytic CO 2 reduction analysed. The efficient modification and engineering of heterojunctions via co-catalyst loading, morphology control and vacancy introduction have been comprehensively reviewed. Third, the state-of-the-art achievements of perovskite-based Z-scheme and S-scheme heterojunctions are systematically summarized and discussed. Finally, the challenges, bottlenecks and future perspectives are discussed to provide a pathway for applying perovskite-based heterojunctions for solar-to-chemical energy conversion. [Display omitted] • Insight into the mechanism and research progress of photocatalytic CO 2 reduction. • Properties of perovskites as photocatalysts and their synthetic routes. • Boosting the CO 2 conversion through perovskite based Z and S-scheme heterojunctions • The charge transfer mechanism and designing of perovskite based heterojunctions • The future expectations, challenges and outlook are presented. [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]