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Waste-derived materials obtained from the recovery and recycling of electronic waste (e-waste) such as batteries and printed circuit boards have attracted enormous attention from academia and industry in recent years, especially due to their eco-friendly nature and the massive increment in e-waste due to technological development. Several investigations in the literature have covered the advances achieved so far. Meanwhile, photocatalytic applications are especially of interest since they maintain mutual benefits and can be used for H2 production from solar water splitting based on semiconductor processing as a proper environmentally friendly technique for solar energy conversion. In addition, they can be utilized to degrade a variety of organic and non-organic contaminations. Nonetheless, to the best of the authors' knowledge, there has not been any comprehensive review that has specifically been focused on e-waste-derived photocatalytic materials. In this regard, the present work is dedicated to thoroughly discussing the related mechanisms, strategies, and methods, as well as the various possible photocatalysts synthesized from e-wastes with some critiques in this field. This brief overview can introduce modern technologies and promising possibilities for e-waste valorization, photocatalytic processes, and new photocatalytic degradation methods of eco-friendly nature. This paper discusses various e-waste-obtained photocatalytic materials, synthesis procedures, and applications, as well as several types of e-waste, derived materials such as TiO2, ZnO, indium tin oxide, and a variety of sulfide- and ferrite-based photocatalytic materials. [ABSTRACT FROM AUTHOR]

Developing interfacial connections is one of the breakthrough strategies to improve the photocatalytic activity. Herein, ZnBi 2 O 4 nanoparticles-ZnO nanorods heterojunction was successfully synthesized and used, as a dual-function photocatalyst, for photocatalytic degradation of Bisphenol A and hydrogen production with improved photocatalytic activity under simulated sunlight irradiation. The highest H 2 production (3.44 mmol g−1 h−1) was obtained for ZnO-20 wt% ZnBi 2 O 4 sample, which is around 12.7 times higher than pure ZnO. According to the HRTEM result, the intimate interfacial connections are formed between ZnO and ZnBi 2 O 4 which could act as trapping centers for charge carriers and results in the boosted photocatalytic activity. Further, a high aspect ratio of 1D ZnO nanorods and small size of 0D ZnBi 2 O 4 nanoparticles (~10 nm) increases the number of interfacial contacts and thus the charge carriers' recombination was suppressed more efficiently. Based on the trapping experiments, ESR and Mott-Schottky analysis, ZnBi 2 O 4 –ZnO hybrid photocatalyst followed the S -scheme charge transfer mechanism. • Novel 0D/1D ZnBi 2 O 4 /ZnO p-n heterojunction was successfully prepared. • The prepared hybrid system revealed improved H 2 production and BPA decomposition. • The highest hydrogen evolution (3.44 mmol.g−1.h−1) was achieved on ZnO–20%ZnBi 2 O 4. • S -scheme mechanism was suggested for boosted photocatalytic activity. • The defects formed at the interfacial contacts decreased the recombination rate. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel visible driven WO 3 -CeO 2 heterojunction was successfully synthesized. • The prepared photocatalyst was applied for degradation of Sulfamerazine from an aqueous solution. • Incorporation of CeO 2 on WO 3 significantly enhanced the photodegradation percentage. • S-scheme mechanism was suggested for the boosted photocatalytic activity. • Photodegradation pathways of Sulfamerazine antibiotic were investigated. In this work, hierarchical WO 3 -CeO 2 hollow sphere heterojunctions were fabricated via a two-step hydrothermal method and applied for degradation of sulfamerazine antibiotic under visible light irradiation. The incorporation of CeO 2 into the WO 3 microspheres was confirmed by XRD, BET, HRTEM, and XPS analysis. The results revealed that the photocatalytic activity of WO 3 -CeO 2 heterojunction was greatly enhanced compared to pure CeO 2 and WO 3 samples, and the highest degradation percentage of sulfamerazine was achieved on the WO 3 -CeO 2 heterojunction with 30 mol. % CeO 2 content. This could be ascribed to the efficient separation of charge carriers which was facilitated by oxygen vacancies formed at the interfaces of two coupled semiconductors. EIS analysis verified that the charge transfer resistance of WO 3 -30CeO 2 heterojunction was decreased, which is due to the heterojunction effect. Moreover, based on the Mott-Schottky calculations, radical trapping experiments and ESR analysis, hydroxide radicals were identified as the main active species, and an S-scheme charge transfer mechanism was suggested to explain the enhanced photocatalytic activity. The possible degradation pathway of sulfamerazine was suggested through the detection of degradation intermediates by mass spectroscopy. [ABSTRACT FROM AUTHOR]

• Novel Bi 2 WO 6 -ZnBi 2 O 4 heterojunction was prepared by sonochemical assisted hydrothermal method. • Sonochemical pretreatment caused spherical to flake-like morphology evolution. • The optimal Bi 2 WO 6 -20ZnBi 2 O 4 revealed good stability (4% loss) after 5 cycling runs. • Direct Z-scheme mechanism was proposed for the enhanced photodegradation of MG. • Bi 2 WO 6 -ZnBi 2 O 4 can efficiently remove both MG dye and colorless 2,4-DCP contaminants. In this work, novel Bi 2 WO 6 -ZnBi 2 O 4 p-n heterojunction was successfully synthesized through combination of sonochemical and hydrothermal procedures. The results revealed that the sonochemically prepared nanocomposites had spherical shape with amorphous structure which became crystalline particles with flak-like morphology after hydrothermal treatment. Bi 2 WO 6 -ZnBi 2 O 4 nanocomposite with 20 wt% ZnBi 2 O 4 content demonstrated the highest photocatalytic performance compared to the pure Bi 2 WO 6 and ZnBi 2 O 4 samples toward the degradation of Malachite Green (MG). This finding is associated with the efficient separation of photo-generated electron/hole pairs due to the formation of interfacial charge transfer between Bi 2 WO 6 and ZnBi 2 O 4. However, further ZnBi 2 O 4 loading had no significant effect on the enhancement of photocatalytic activity of nanocomposite samples owing to the shielding effect of ZnBi 2 O 4 against incident light. The obtained results were further verified by optical and photocurrent density measurements. Based on the obtained results from active species trapping experiments, electron spin resonance and Mott-Schottky calculations, the Z-scheme charge transfer pathway was proposed as the predominant mechanism for the photocatalytic reactions. Also, the photocatalytic degradation of 2,4-dichlorophenol, as a colorless model pollutant, was conducted on optimal composite sample to study the possible contribution of MG dye sensitization mechanism in the enhancement of photocatalytic efficiency. [ABSTRACT FROM AUTHOR]

[Display omitted] • Sn decorated Fe NPs was functionalized with leucine by chemical reduction technique. • The bimetallic Sn decorated Fe NPs was used for detection of trivalent chromium. • The Sn-Fe NPs catalyst was used to degradation of methyl orange. • The particles exhibited excellent antibacterial activities. In this project, Sn-Fe bimetallic nanoparticles were prepared by a facile method. The bimetallic nanoparticles of it could be well established by a field emission scanning electron microscope micrographs. Due to the excellent synergistic influence between Sn-Fe nanoparticles and leucine indicated a great performance for determination of Cr3+. The material was characterized using the XRD, DLS, and zetasizer for the evaluation of crystal structure and morphology information. The potential and effective size of Sn-Fe NPs was −29.10 mV and 30 nm, respectively. Cr3+ ions interaction with the Sn-Fe NPs-leucine probe was carried out in 1 min as response time. The limit of detection of Sn-Fe NPs for Cr(III) colorimetric method was 0.25 nM. The prepared nanoparticles showed impressive photocatalysis efficiency for degradation of MO was about 95.1% in 35 min, thus the prepared nanoparticles may be developed for the detoxification of pollution. The prepared nanoparticles depicted effective antibacterial activity against C. botulinum and, H. pylori bacteria. [ABSTRACT FROM AUTHOR]