Search

Here, we demonstrate the effect of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and molybdenum trioxide (MoO3) hole transport layers (HTLs) on degradation of the bulk-heterojunction organic solar cell (OSC) with the combination of two active layers—poly(3-hexylthiophene) and poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl]]. The study is performed for unencapsulated conventional structure OSCs exposed to the ambient dark condition. In the self-life test situation, it is found that PEDOT:PSS based devices show an initial higher short circuit current and subsequent faster degradation with time in comparison to the MoO3 based devices. The effects of these HTLs have been shown in terms of better charge extraction and a decrease in the shunt resistance as well as the bulk resistance of the active layer. The charge carrier generation probability evaluated from photocurrent data shows the dominant impact of active layer degradation rather than the oxidation of a top electrode under the ambient condition. This suggested mechanism is further supported by impedance spectroscopy as well as the evaluated transit time, global mobility, and exciton dissociation probability, establishing that the degradation does not much affect the transport property of the active material. Rather, it affects more the carrier generation rate. The low hole extraction barrier in PEDOT:PSS based devices show small transit time and high global mobility compared to MoO3. It is found that during the degradation process, the bulk resistance of the device significantly increases, which reduces the diffusion current in the device. [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]

[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] • 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]

[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]

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]

A binary S-scheme heterojunction photocatalyst, ZIF-67/Ag 3 VO 4 (ZAV), was successfully synthesized using a hydrothermal technique. The optimal ZAV-30 (ZIF-67/30 wt%Ag 3 VO 4) demonstrated excellent performance by degrading 98.5% of Venlafaxine (VEN) within 60 min under visible light. Extensive investigations were carried out regarding the crystal structure, morphology, composition, specific surface area, optical characteristics and electrochemical impedance. The ZAV-30 heterojunction photocatalyst outperformed bare ZIF-67 and Ag 3 VO 4 photocatalysts, primarily due to enhanced photon absorption and improved charge carriers' separation via S-scheme transfer, redox capability and high charge transfer capacity supported by electrochemical experiments and photoluminescence. The S-scheme transfer was validated by in-situ XPS measurements after light exposure. Scavenger experiments indicated that both •OH and •O 2 − played crucial roles as active species in the photocatalytic process. Mass spectrometry (MS) analysis of intermediates facilitated the proposal of a probable photocatalytic degradation pathway for VEN. The photoactivity of the heterojunction was influenced by a range of factors including the pH of the VEN solution, initial VEN concentration, ZAV photocatalyst dosage, and ion effects. Interestingly the ZAV-30 heterojunction exhibited superior performance in lake water, tap water and river water too. Importantly, the ZAV-30 heterojunction exhibited excellent stability and reusability, making it a promising photocatalyst. [Display omitted] • ZIF-67/Ag 3 VO 4 S-scheme heterojunction synthesized by hydrothermal technique. • ZAV-30 demonstrated 98.5% degradation of Venlafaxine within 60 min under visible light. • The S-scheme transfer accelerates charge transfer, separation and strong redox capability. • •OH and •O 2 − as main active species for photocatalytic degradation • High mineralization, reusability and durability. [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]

• Metallic Ag mediated Ag 2 CrO 4 /BiFeO 3 junction on RGO matrix. • Wide spectrum response– High performance in UV, Vis, NIR and Solar light. • Triggering effect of Metallic Ag and RGO-electron mediation and facilitation. • Selective Production of CH 4 from CO 2 without any co-catalyst. • High performance photo-reduction of BrO 3 − and degradation of ciprofloxacin. Designing highly optical active photocatalytic heterojunctions with multi-pronged capabilities for environmental applications is still a challenge. In this work the photocatalytic potential of Ag 2 CrO 4 /Ag/BiFeO 3 @RGO was systematically tested via photo-reduction of BrO 3 −, degradation of Ciprofloxacin (CIF) and photo-reduction of CO 2 under broad light spectrum. Among various samples ABR-8 exhibits 99.6% BrO 3 − photoreduction and 96.3% CIF photo-oxidation in 90 min (nearly 96% in 60 min). ABR-11 (with 11 wt% RGO) selectively generates 180 μmol g−1 of CH 4 in 8 h under visible light (260 μmol g−1 under alkali activation) which is approximately 60 times than bare BiFeO 3. The excellent performance of ABR series is attributed to successful formation of Z-scheme which assists in efficient charge transfer, reduced recombination and wide spectrum response. In addition the electron donation-mediation of plasmonic Ag0 and adsorption-electron mediation of reduced graphene oxide has a triggering effect on reductive and oxidative capabilities. The band structure analysis, scavenging experiments and electron spin resonance studies make it possible to predict a suitable mechanism for bromate reduction, CIF degradation and CH 4 generation. Electron assisted BrO 3 − reduction, •OH and •O 2 − radicals powered CIF degradation by Z-scheme mechanism and multi-electron single step proton-coupled mechanism for highly selective CH 4 production were predicted. The best performing photocatalyst retain over 95% of performance over five consecutive runs. Suitable optimisations lead to higher performance from BiFeO 3 which bears many shortcomings via interfacial junction with Ag 2 CrO 4 with triggering effect from metallic Ag and RGO. Intelligently designed junctions can thus show strong photo-oxidative and reductive capabilities with further scope of fine tuning. Hence this developed heterojunction can be sustainably utilized for multi-pollutant removal and energy/fuel production under broad spectrum of light. [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]

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]

Here in, we report a, wide spectrum active, Bi nanodots incorporated CuBi 2 O 4 /Bi/CuFe 2 O 4 (CBC) heterojunction for synchronous photodegradation of imidacloprid pesticide (ICP) and photo-reduction of Cr(VI) to Cr(III). The best performing heterojunction sample CBC-30 shows nearly 100% Cr(VI) photo reduction (in less than 45 min) along with 98.2% ICP removal in 60 min. 88.7% Cr (VI) reduction & 83.2% ICP degradation was achieved under sunlight with good activity in NIR region. Scavenging experiments reveal the synchronous role of photoreduction-oxidation with electrons as active species for chromium reduction and holes for organic pollutant degradation. This is ensured by effective Z-scheme transfer between CuBi 2 O 4 and CuFe 2 O 4 leading to protection of high potential conduction and valence bands with strong redox capabilities. The Bi nanodots played an important role via wide spectral response owing its surface plasmon resonance as well as photoinduced electron transfer mediation which promotes the electrons transfer efficiency and enhanced photocatalytic ability. [Display omitted] • Z-scheme CuBi 2 O 4 /Bi/CuFe 2 O 4 has excellent charges separation efficiency. • Bi nanodots-wide spectral activity-mediator- provide hot electrons. • Remarkable synchronous removal of imidacloprid and Cr (VI). • Degradation route for ICP and cooperative mechanism for reduction-degradation. • Efficient activity in solar light and river water too. [ABSTRACT FROM AUTHOR]

The development of novel visible powered nano-heterojunctions with multi-pronged capabilities for environmental and catalytic applications has been gaining importance for persistent pollutant degradation & clean energy production. A magnetically recoverable biochar supported ternary g-C 3 N 4 /Bi 2 O 2 CO 3 /CoFe 2 O 4 heterojunction (BCBF) was fabricated which shows a high visible photoactivity. The heterojunction was used for degradation of pesticide paraquat under visible radiation (Xe lamp), natural sunlight, photo-ozonation, peroxymonosulphate, and coupled conditions. A high degradation of 99.3% was achieved under visible radiation in 90 min and 92.1% under solar light in 120 min. Biochar supported ternary junction performs manifold faster than Bi 2 O 2 CO 3 /CoFe 2 O 4 , g-C 3 N 4 /CoFe 2 O 4 , g-C 3 N 4 /CoFe 2 O 4 , Bi 2 O 2 CO 3 (BOC), CoFe 2 O 4 (CF) and g-C 3 N 4 (CN). The effect of operational parameters as effect of pH, H 2 O 2 , anions, ozone and peroxymonosulphate (PMS) was also studied. In BCBF + PMS + O 3  + Vis protocol a spectacular complete degradation was observed in less than 30 min. Ternary band structure efficiently reduces the charge recombination rate and promotes spectral activity which was confirmed by photoluminescence, photocurrent response and EIS analysis. By LC-MS, scavenging experiments and ESR studies a possible mechanism was also proposed. Cyto-toxicity studies of degraded products on human peripheral blood cells revealed almost 99% cell viability affirming the complete mineralization. The junction was also used for reduction of 4-nitrophenol into 4-aminophenol with complete conversion in less than 5 min with rate constant 13.05 × 10 −3  s −1 . In addition the ternary junction shows a high visible powered conversion of CO 2 producing CH 4 (∼119 µmol g −1 ), CO (∼131 µmol g −1 ) and O 2 (∼242 µmol g −1 ) with a high rate constant of 13.05 × 10 −3  s −1 . [ABSTRACT FROM AUTHOR]

[Display omitted] • Fundamentals of S-scheme and dual S-scheme have been discussed. • Types of heterojunctions are elaborated with mechanism comparisons. • Recent developments in synthetic methods and different morphology of S-scheme and dual S- schemes. • S-scheme and dual S-scheme for photocatalytic environmental remediation and energy production. • Bottlenecks, conclusion and future prospects discussed. Discovering alternative materials and technologies that provide the meaningful potential to environmental and energy-related challenges in critical to the long-term viability of industrial activity and the evolution of society. Photocatalysts are undeniably important, and scientists are working hard to improve their photocatalytic performance. The high recombination rates of photogenerated electron-hole pairs as well as poor redox capability are addressed via heterojunction modification. In this direction, oxidation type and reduction type photocatalysts based S-scheme heterojunctions are highly promising owing to highly diminished recombination facilitated by internal electric field. This review has focused on the shift from Z-scheme to new revolutionary S-scheme based photocatalytic materials with high performance applications in the field of energy and environment. It can be concluded that controllable built-in electric field intensity and stable interfacial carrier transport process make S-scheme heterostrctures ideal. However their application is mainly limited to powder photocatalysts, don't apply to photo-chemistry and solar cells with external circuit, reaction thermodynamics and dynamics management in S-scheme photocatalysts is not adequate. To some extent, dual S-schemes address to these limitations and further research is to be carried out to fight the bottlenecks. Several perspectives on the future of S-scheme and dual S-scheme heterostructure were also provided based on rigorous review of the reported results. A discussion on the previously reported different types of heterojunctions and S-schemes is presented in this review along with plausible charge transfer mechanisms. The synthetic routes to S-scheme heterojunctions are also provided along with modifications and combinations. The current designing and perspective applications in numerous pollutant degradation, hydrogen production and CO 2 conversion is selectively highlighted. The transition of mechanism elucidation from Z-scheme to S-scheme has been discussed with suitable case studies. However, S-scheme heterojunctions designing and fabrication is still new commercially and so present readiness and bottlenecks have been discussed. Hence it is quite imperative for a future roadmap to be laid to design and develop economically viable high performance S-scheme heterojunctions. [ABSTRACT FROM AUTHOR]

The step-scheme (S-scheme) heterojunctions with superior redox capability have recently emerged as one of the most promising materials for cleaning up of contaminated environments. Herein, we synthesized g-C 3 N 4 /NiFe 2 O 4 (NFC) heterojunction photocatalyst via a hydrothermal route for the degradation of Cephalexin (CPX). The integration of g-C 3 N 4 and NiFe 2 O 4 into heterojunction with an effective S-scheme transfer which prevents the recombination of essential photoexcited electron-hole pairs leads to excellent 99.3% of photocatalytic degradation of CPX within 60 min under visible light. The scavenging experiments suggested •OH and •O 2 - radicals generated on high potential bands of S-Scheme g-C 3 N 4 /NiFe 2 O 4 as active species responsible for high performance CPX removal. The degradation intermediates were examined by Liquid Chromatography mass spectroscopy (LC-MS) and a probable pathway of CPX degradation was proposed accordingly. The inherent work function between g-C 3 N 4 and NiFe 2 O 4 leads to bending of conduction and valence bands which subsequently forms an built-in electric field across the interface facilitating the superior separation of photogenerated electrons and holes. The five subsequent recycling tests demonstrated the catalyst's strong photocatalytic stability and the easy recovery process because of its magnetic characteristic. This research may bring fresh insights for constructing magnetic photocatalysts based on g-C 3 N 4 , which are both highly effective and stable. Additionally, it also paves a path for the designing of S-scheme heterojunctions with great performance for environmental remediation applications. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Ni 5 P 4 /g-C 3 N 4 S-scheme dual-function heterojunction photocatalyst was prepared. • 25NP/CN junction shows 40.1 mmol g-1h-1H 2 evolution and 94.4 % CBZ removal in a coupled process. • Holes and OH radicals for CBZ degradation and electrons for H 2 generation via e-/H 2 O and 2e-/2H+. • Intermolecular H+ transfer via cyclic intermediate between Ni and degradation products. • Junction works in oxic/anoxic mediums- detailed mechanisms analysed. With a goal of waste-to-energy conversion, herein we report synchronous hydrogen evolution and pollutant degradation via photocatalysis utilizing novel Ni 5 P 4 /g-C 3 N 4 S-scheme (Step scheme) heterojunction. The 25 %Ni 5 P 4 /g-C 3 N 4 (25NP/CN) sample generates 40.1 mmol g-1h-1hydrogen evolution and 94.4 % carbamazepine degradation simultaneously under visible light and anaerobic conditions. Furthermore, the hydrogen evolution with carbamazepine, bisphenol A, sulfamethoxazole and rhodamine B is manifolds higher than in water. From The in-situ XPS results confirm the S-scheme transfer between Ni 5 P 4 and g-C 3 N 4. The presence of Ni0@Ni 5 P 4 where strong covalent interactions between Ni0 and Ni-P single layers on Ni 5 -P 4 not only enhanced the visible absorption, charge transfer but also leads to hydrogen formation by H+ transfer via a cyclic intermediate in a co-ordinate complex of degradation intermediates with Ni. This route is in addition to obvious e-/H+. The CBZ degradation and hydrogen evolution in aerobic/oxic conditions was also studied and 25NP/CN performs well under this atmosphere, inferring that oxidised intermediates act as electron donors and maintains the H 2 evolution in longer run too. The photogenerated holes directly oxidized the pollutant in addition to OH radicals in anoxic medium and separated/accumulated electrons leads to hydrogen evolution. The scavenging experiments reveal that photogenerated holes directly oxidized the pollutant in addition to OH radicals in anoxic medium and separated/accumulated high potential electrons (via S-scheme transfer) leads to hydrogen evolution. The clean energy production and pollutant mineralization are synchronously achieved. Henceforth, a waste-to-energy route is proposed by coupling photocatalytic hydrogen evolution to environmental restoration. [ABSTRACT FROM AUTHOR]

To achieve good living standards, it is critical to make high-performance toxic gas sensing devices for public safety, environmental pollutant control, industrial operations, and other applications. For this purpose, we demonstrate CuO anchored SnO 2 nanostructures for H 2 S gas sensors. The selectivity was improved by anchoring with CuO for a total 60 s duration at four equal consecutive cycles to achieve good selectivity towards H 2 S molecules. The pristine CuO shows instability and metallic behaviour when it is exposed to H 2 S for a longer time. Furthermore, the proposed gas sensor shows good selectivity toward H 2 S as compared to other gases H 2 , NO 2 , CO 2 , and NH 3. The sensing response was measured at around 69 % at the optimal operating temperature of 150 °C. It is observed that CuS formation has better selectivity as compared to pristine SnO 2 and a slight improvement in sensitivity is observed. As a result, a promising strategy for designing and producing good-performance H 2 S gas sensors would be to CuO anchor on SnO 2 nanostructures. The proposed sensors may be integrated with IoT platforms and used for the detection of H 2 S in the sewer line and leak detection in the petroleum industry. [Display omitted] • SnO 2 thin film was anchored with CuO at different time duration using RF sputtering for H 2 S gas sensing. • The sensor exhibits higher sensing response of 69 % at 150 ºC for 100 ppm of H 2 S with a LoD of 1 ppm. • Comparative analysis was performed for H 2 S gas detection for both SnO 2 and CuO/SnO 2 based sensors. • Excellent selectivity and slight improved sensitivity was observed with CuO/SnO 2 based gas sensor. [ABSTRACT FROM AUTHOR]

Extensive research is being done to develop multifunctional advanced new materials for high performance photocatalytic applications in the field of energy production and environmental detoxification, MXenes have emerged as promising materials for enhancing photocatalytic performance owing to their excellent mechanical properties, appropriate Fermi levels, and adjustability of chemical composition. Numerous experimental and theoretical research works implied that the dimensions of MXenes have a significant impact on their performance. For photocatalysis to thrive in the future, we must understand the current state of the art for MXene in different dimensions. Using MXene co-catalysts in widely used in photocatalytic applications such as CO 2 reduction, hydrogen production and organic pollutant oxidation, this study focuses on the most recent developments in MXenes based materials, structural modifications, innovations in reaction and material engineering. It has been reported that using 5 mg of CdS–MoS 2 -MXene researchers were able to generate as high as 9679 μmol/g/h hydrogen under visible light. The MXenes based heterojunction photocatalyst Co 3 O 4 /MXene was utilized to degrade 95% bisphenol A micro-pollutant in just 7 min. Numerous novel materials, their preparations and performances have been discussed. Depending upon the nature of MXene-based materials, the synthesis techniques and photocatalytic mechanism of MXenes as co-catalyst are also summarized. Finally, some final thoughts and prospects for developing highly efficient MXene-based photocatalysts are provided which will indeed motivate researchers to design novel hybrid materials based on MXenes for sustainable solutions to energy and pollution issues. [Display omitted] • MXenes as new interesting class of photocatalysts. • Composites and heterojunctions with 0D, 1D, 2D, 3D MXenes. • Variable and tunable optical band gaps. • Suitable for energy production and pollution mitigation. [ABSTRACT FROM AUTHOR]

Designing and fabrication of smart hybrid multifunctional materials for energy/fuel production and environmental detoxification is indeed of great significance for sustainable development. Herein, we synthesized a new well-structured S-scheme heterostructure Fe@TiO 2 /Boron Carbon nitride (FT/BCN) with high performance tetracycline degradation and selective CO 2 photo-reduction to CH 4. Under visible light irradiation, 96.3% tetracycline was degraded in 60 min using best performing FT30/BCN sample with a high 83.2% total organic carbon removal in 2 h. The tetracycline degradation rate for FT30/BCN composite catalyst was ∼7 times than bare boron carbon nitride (BCN). The impact of reaction parameters as pH, presence of interfering electrolytes, light source and water matrix was also investigated. The FT30/BCN photocatalyst shows dramatic improvement in CO 2 photoreduction as exhibited in 24.7 μmol g−1 h−1 CH 4 and 2.4 μmol g−1 h−1 CO evolutions with optimal 91.1% CH 4 selectivity. Pure BCN shows a poor 39.1% selectivity. Further, effect of alkali activation, CO 2 /H 2 O feed ratio, reducing agent and light source onto CH 4 production and selectivity was also investigated. The CH 4 evolution and selectivity was improved because of enhanced visible light absorption, high adsorption potential, charge carrier separation and high reducing power of photogenerated electrons induced by an effective S-scheme heterojunction between Fe@TiO 2 and boron carbon nitride. An S-scheme (step-scheme) charge transfer mechanism is here operative both during tetracycline removal and CO 2 reduction. The drug degradation route and photocatalytic mechanism for antibiotic removal and CO 2 reduction was also predicted. [Display omitted] • Fe@TiO 2 /Boron carbon nitride heterojunction fabricated by hydrothermal route. • High performance antibiotic removal under visible and solar light. • Photo-induced CO 2 reduction with H 2 O for highly selective CH 4 production. • Efficient S-scheme charge transfer mechanism observed between Fe@TiO 2 and BCN. • Antibiotic degradation and selective CH 4 production detailed mechanism elucidated. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel Z-scheme Bi 7 O 9 I 3 /B 4 C heterojunction synthesized by hydrothermal route. • Antibiotic as sacrificial agent- H 2 evolution and antibiotic removal simultaneously. • Antibiotic degradation route and photocatalytic mechanism probed. • Waste to clean energy concept. The dual-function photocatalytic systems with a promising capability for hydrogen evolution and simultaneous pollutant degradation are surely a significant step towards waste-to-energy conversion goals. However, the performance of such photocatalysts is often limited by poor visible-light activity, charge separation and surface reverse reaction involving photogenerated electrons and radicals/intermediates. In this work, we report hydrothermal synthesis of novel Bi 7 O 9 I 3 /B 4 C (BIBC) heterojunction photocatalyst for advanced Norfloxacin antibiotic degradation with simultaneous hydrogen evolution under visible light. In particular, BIBC-30 heterojunction shows H 2 evolution rate of 812 μmol g−1h−1 with simultaneous 94.2% NFN removal which are much higher than bare B 4 C (∼6 times) and Bi 7 O 9 I 3 (∼4 times). Under oxic/aerobic conditions too, a high 456.3 μmol g−1h−1H 2 evolution with nearly complete norfloxacin degradation was achieved. The low band gap of Bi 7 O 9 I 3 and presence of metallic Bio extends the absorbance to NIR region and B 4 C enlarges the surface area of junction along with suppression of the back reaction. It was observed that BIBC heterojunction exhibits manifolds H 2 evolution rate with NFN as sacrificial agent (18.3% apparent quantum efficiency) is manifolds higher than pure water, methanol, triethanolamine and rhodamine B. An effective Z-scheme charge transfer facilitated by Bio is active in the intimately coupled heterojunction with suitably placed energy bands. This work shows that waste to energy conversion can be promisingly achieved by performing H 2 evolution and pollutant removal simultaneously. [ABSTRACT FROM AUTHOR]

Solar-light powered environmental detoxification is surely a promising and sustainable approach for common goals of human development and ecosystem preservation. Focussing on this, we herein report fabrication of a novel solar active heterojunction Fe 3 O 4 @SrTiO 3 /Bi 4 O 5 I 2 an in-situ hydrothermal route. The heterojunction was used for the degradation and mineralization of anti-inflammatory drug Diclofenac (DCF) as target pollutant under simulated solar-light irradiation. Current results reveal that the optimized junction displayed 98.4% diclofenac removal in 90 min with 87.2% mineralization. The ESR probe suggests that both ●OH and ●O 2 − radicals are active species involved in DCF degradation. Analysing the band structure, thermodynamic feasibility and the photocatalytic performance, a traditional mechanism was ruled out and a Z-scheme transfer was predicted. The charge separation was obviously drastically improved by the Z-scheme transfer and facilitation by Fe 3 O 4 and Ti4+/Ti3+ in-built redox mediator. A degradation route was predicted on basis of intermediates detected by liquid-chromatography mass spectrometry analysis. This work promises to provide future possibilities for rational designing and fabrications of semiconductor heterojunctions for solar environmental applications. [Display omitted] • Solar active Fe 3 O 4 @SrTiO 3 /Bi 4 O 5 I 2 heterojunction formed by in-situ hydrothermal route. • High performance removal of diclofenac under simulated solar light. • Low recombination, high charge transfer capacity and photocurrent response. • Fe 3 O 4 and Ti4+/Ti3+ in-built redox for facile Z-scheme transfer. • ●OH and ●O 2 − radicals are both active species-High magnetic separation [ABSTRACT FROM AUTHOR]

• Dual Z-scheme g-C 3 N 4 /Bi 4 Ti 3 O 12 /Bi 4 O 5 I 2 heterojunction by in-situ hydrothermal route. • High performance synergistic H 2 evolution and antibiotic removal under visible light. • Intimately transfer mediated by in-built I 3 −/I− and Bi5+/Bi3+ redox mediator. • h+ and OH radicals as active species for antibiotic degradation-ESR probe. • Antibiotic degradation route and photocatalytic mechanism predicted. Inspired by waste to energy production, we report construction of dual Z-scheme advanced photocatalyst g-C 3 N 4 /Bi 4 Ti 3 O 12 /Bi 4 O 5 I 2 heterojunction for coupled photocatalytic H 2 evolution and degradation of antibiotics with high efficiency. The optimal CTBT-30 i.e (40 %g-C 3 N 4 /Bi 4 Ti 3 O 12)/30 % Bi 4 O 5 I 2 photocatalyst exhibited an excellent rate of H 2 production under visible light (56.2 mmol g−1 h−1) along with simultaneous 87.1 % ofloxacin (OFL) removal. The H 2 production rate is manifolds higher than in ultrapure water, sulfadiazine, rhodamine B and higher in hole scavenging triethanolamine. The interfacial intimate coupling with well-matched energy bands, foster the charge separation with effective Z-scheme transfer facilitated by I 3 −/I− and Bi3+/Bi5+ and redox mediators. The scavenging of majority of holes for direct oxidation or via OH radical formation leaves photogenerated electrons (at CB of g-C 3 N 4 and Bi 4 O 5 I 2) free for H 2 evolution from H 2 O. Such work is promising for designing high photo-absorbing heterojunction photocatalysts for dual functionalities of clean energy production and environmental detoxification. [ABSTRACT FROM AUTHOR]

• Novel 3-D silicate glass@Cu 2 O/Cu 2 V 2 O 7 p-n heterojunction fabricated. • Internal electric field-deep contact-facilitation of charge carrier movement. • High performance removal of sulfamethoxazole under visible light. • O 2 − as active species-ESR probe-high potential band protection-Z-scheme. • 3-D silicate glass-transmission & light scattering-high quantum yield. Focusing on the treatment of pharmaceuticals contaminated water by advanced oxidation processes, a novel three dimensional silicate glass matrix (3-DG) coupled Cu 2 O/Cu 2 V 2 O 7 p-n heterojunction was constructed by in-situ hydrothermal technique. The optimal Cu 2 O/Cu 2 V 2 O 7 with 30 wt % Cu 2 V 2 O 7 (CV-30) degrades 90.1 % sulfamethoxazole (SMX) in 60 min and nearly 100 % removal in 45 min via coupling with 3-DG. Under natural sunlight ∼ 80 % SMX removal was observed. The internal electric field of the p-n junction facilitates the electron flow via the interface. 3-D silicate glass increases the visible light absorption dramatically via internal reflection which facilitates higher exposure for the junction and shortens the diffusion length of charge carriers. The effect of reaction parameters suggests that HCO 3 − and C O 3 2 − ions substantially escalate the SMX removal rate. Scavenging experiments and ESR probe suggest O 2 − as the main active species followed by OH radicals. The degradation products were detected by LC–MS analysis and a degradation mechanism was also predicted. The photocatalytic mechanism was explained in terms of the electron transfer facilitated by conventional transfer and Z-scheme. This strategy to construct such highly visible and solar active p-n heterojunctions will pave way for future opportunities for the degradation of recalcitrant pharmaceutical pollutants. [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]

Low frequency Capacitance- voltage (C-V) measurements have been employed to investigate the effect of thickness variation of poly (3-hexylthiophene (P3HT) and fullerene [6,6],-phenyl-C 61 -butyric acid methyl ester(PCBM) based Bulk Heterojunction (BHJ) photo absorbing layer in inverted organic solar cell (OSC) configuration, ITO|ZnO|P3HT:PCBM|MoO 3 |Ag and are corelated with different recombination mechanisms. The normalized capacitance (C C geom ) with voltage curves at different P3HT: PCBM blend thicknesses such as 130, 100, 80 and 70 nm demonstrate an increase in peak height with thickness as well as the presence of negative capacitance (NC) beyond peak voltage for higher thicknesses. To understand both peak height variation and the occurrence of NC, a defect sensitive simulation study has been performed by employing the radiative and non-radiative recombination processes. Based on the analysis of simulation results we confirm the role of Langevin bimolecular recombination rate in determining the peak height with thickness; however, the presence of NC in C-V curves can be understood through a competition between the Langevin bimolecular, and trap assisted recombination rates. Study confirms that peak height reduces due to increase in the rate of Langevin bimolecular recombination, whilst the trap assisted recombination resurges the NC beyond peak voltage. Later, the utilities of D-D based 1 C 2 3 vs V analysis to calculate built-in voltage (V bi) have been performed for the experimental and simulation data at different thicknesses emphasizing the strength of this approach to characterize threshold voltage of organic diodes. [Display omitted] • Thickness dependent C-V characteristics of P3HT: PCBM BHJ solar cells are investigated. • Peak height and negative capacitance beyond peak voltage is found to depend on P3HT: PCBM thickness. • Langevin bimolecular recombination suppresses peak height of low-frequency C-V curves. • Trap-assisted recombination plays an important role in determining negative capacitance beyond peak voltage. [ABSTRACT FROM AUTHOR]

The photoactive film morphology of ternary molecules blend bulk heterojunction organic solar cell was investigated using various solvent additives. Two donor polymers namely poly(3-hexylthiophene) (P3HT) and thieno[3,4-b]thiophene/benzodithiophene (PTB7) at (1:1) stoichiometric ratio were employed together with (PCBM) fullerene molecule in the preparation of the solar cells. The photoactive films were treated with either uni- or binary solvent additives to improve film morphology and the miscibility of the molecules in the medium. The significant improvement on the performances of the devices were recorded using binary solvent additives (∼1% vol.) with power conversion efficiency improvement as high as 4.1% compared to 2.9% measured from the films treated with single additive solvent. The correlation between solar cell performance and film morphology have been discussed in terms of optical, electrical and surface morphology of the active layers of solution processed organic solar cells. [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]

Pure and zinc-doped cobalt oxide heterojunction devices on n-type silicon substrates have been fabricated via sol-gel spin coating deposition. The fabricated devices have been characterized by XRD, Raman spectroscopy, FESEM, and EDS elemental mapping. The fabricated heterojunction devices show non-linear I-V characteristics, which suggests their diodic behavior. A blend of mathematical and physical methods that are based on the Lambert W function and the modified Shockley equation has been used to examine the performances of the devices. The UV sensing measurements were conducted on the devices under zero bias conditions while they were subjected to UV light with wavelengths of 365 and 254 nm. The study has indicated that Co 3 O 4 in its pure form does not exhibit activity towards either UV wavelength. However, the introduction of Zn2+ into Co 3 O 4 results in a notably substantial photoresponse of approximately 978 %, 1393 %, and 2400 % for Zn2+ concentrations of 5 %, 15 %, and 30 %, respectively, when exposed to 365 nm UV radiation. The responsivity value of the fabricated devices was found to increase from 0.026 mA/W to 15.82 mA/W with an increase in Zn2+ from 5 % to 30 %. Detectivity and EQE values of the devices also demonstrate remarkable increase from 7.50 × 108 cmHz1/2/W (5 % Zn2+) to 2.86 × 1010 cmHz1/2/W (30 % Zn2+) and from 0.009 % (5 % Zn2+) to 5.39 % (30 % Zn2+) respectively. The increase in Zn2+ concentration also increases the linear dynamic range (LDR) value from 20.65 dB to 27.96 dB. • Sol-gel spin coating technique was used to fabricate p-Co 3 O 4 /n-Si and p-ZnCo 2 O 4 /n-Si heterojunctions. • Ultra-violet photodetectors were fabricated using the metal oxide heterojunctions. • Embedment of Zn2+ ions in Co 3 O 4 thin films give rise the UV photoconductivity. • Device performance parameters like responsivity, detectivity, EQE, and LDR were studied. • Current-voltage characteristics were theoretically fitted modified Shockley equation. [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]