Search

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 widespread use of organic dyes that are discharged into wastewater from many sectors continues to be a top environmental issue today. The UV–Visible light driven photocatalytic environmental purification is a highly promising field, and spinel ferrites are the prime applicant for waste water purification. In this work, pure phase cobalt doped Mg–Zn nanoferrites with a composition of Mg0.5Zn0.4Co0.1Fe2O4, Mg0.4Zn0.5Co0.1Fe2O4, and Mg0.5Zn0.5Co0.1Fe1.9O4 were fabricated using economic and facile combustion process. The prepared catalysts were caharcteriazed for structural, optical and magnetic properties. The catalyst Z5C1 exhibits 97.76% crystal violet degradation in 90 min under UV–Visible light. The superior photocatalytic efficiency of the Z5C1 catalyst is attributed to the lowest charge carrier recombination rate and moderate band gap of the catalysts. The scavenging experiments revealed the role of holes as reactive species in the catalytic degradation of crystal violet dye. The reusability investigations and simplicity of magnetic separation of the manufactured catalyst show that catalysts have the potential to degrade crystal violet dye and other organic contaminants. [ABSTRACT FROM AUTHOR]

Antibiotic water contamination is a growing environmental problem in the present day. As a result, water treatment is required for its reduction and elimination. Due to their important role in resolving this issue, photocatalysts have drawn a great deal of interest over the past few decades. When non-biodegradable organic matter is present in polluted water, the photo catalytic process, which is both environmentally friendly and an improved oxidation method, can be an effective means of remediation. In this regard, we report the successful synthesis of pure phased rare earth doped ZnO nanoparticles for tetracycline degradation. The prepared catalysts were systematically characterized for structural, optical, and magnetic properties. The optical band gap was tailored by rare earth doping, with redshift for Sm and Dy doped nanoparticles and blueshift for Nd doped ZnO nanoparticles. The analysis of photoluminescence spectra revealed information about the defect chemistry of all synthesised nanoparticles. Magnetic studies revealed that all synthesized diluted magnetic semiconductors exhibit room temperature ferromagnetism and can be employed for spintronic applications. Moreover, Dy doped ZnO nanoparticles were found to exhibit a maximum degradation efficiency of 74.19% for tetracycline (TCN) removal. The synthesized catalysts were also employed for the degradation of Malachite green (MG), and Crystal violet (CV) dyes. The maximum degradation efficiency achieved was 97.18% for MG and 98% for CV for Dy doped ZnO nanoparticles. The degradation mechanism involved has been discussed in view of the reactive species determined from scavenging experiments. [ABSTRACT FROM AUTHOR]

Energy shortage and escalating pollution are major challenges globally. Heterogeneous photocatalysis is one of the most cost-effective methods for producing renewable energy and removing pollutants. In particular, ZnO nanostructures are promising photocatalysts that are economic, stable, and biologically safe. ZnO-based nanoheterostructures have been used for heavy metal reduction, organic pollutants degradation, photocatalytic hydrogen production, and drug mineralization. Here, we review ZnO-based nanoheterojunctions as photocatalysts for hydrogen production and pollutant degradation. Hydrogen production has reached 1200 mol g−1 h−1 using Ce-doped ZnO/ZnS heterojunction, with a 8.5-fold higher efficiency than bare ZnO. Nearly complete removal of a dye pollutant was achieved in 15 min using hybrid ethyl cellulose-modified g-C3N4/ZnO. Moreover, ZnO/Ag2WO4/Fe3O4 showed a 152% and 143% higher antibiotic degradation rate than bare Ag2WO4 and ZnO, respectively. We present methods to modify ZnO, including coupling with other semiconductors, metal/non-metal doping, and carbon-based materials coupling; and methods for charge divergence in binary and ternary ZnO-based nanocomposites. [ABSTRACT FROM AUTHOR]

To address the global energy crisis and widespread environmental deterioration issues, semiconductor photocatalysts have been widely recognized and studied. In this direction, new-age materials as zeolitic imidazolate frameworks (ZIFs), belonging to a sub-class of metal-organic frameworks (MOFs) have piqued the interest of researchers as prospective photocatalyst candidates. With huge specific surface area, tuneable porosity, diverse structure, ease of designing and controllable properties, ZIFs are highly sought-after material for pollutant degradation and clean energy generation. Additionally, ZIFs may undergo thermal processing to produce functional substances with similar structural characteristics but improved light responsiveness and electron transfer abilities. Numerous functional materials and better photocatalysts can be prepared by thermal treatment of ZIFs, formation of composites, heterostructures with other semiconductors or electron mediators which may have similar structural characteristics but better light capture abilities, charge transfer capabilities and strong redox properties. This paper carefully summarizes and analyses the applications of ZIFs based photocatalysts for photocatalytic organic pollutant degradation, hydrogen generation and CO 2 conversion. A sincere attempt has been made to lay down mechanistic insights into synergism of the structural and electronic properties of ZIFs with other catalyst counterparts for superior photocatalytic performance with focus on band structure analysis, charge transfer mechanisms and performance. Finally, the achievements, novelties and bottlenecks have been discussed and future research directions have been proposed. [Display omitted] • ZIFs as photocatalytic materials-Special structure and properties. • Synthetic routes to ZIFs based composites and heterojunctions. • Applications for CO 2 reduction, H 2 evolution and water treatment. • Detailed discussion on synergism with semiconductors and mechanisms. • Challenges, opportunities and future prospects were fully debated. [ABSTRACT FROM AUTHOR]

[Display omitted] • Co 0.75 Zn 0.25 Fe 2 O 4 nanoparticles were successfully stacked over carbon nitride sheets. • The g-C 3 N 4 / Co 0.75 Zn 0.25 Fe 2 O 4 were tested for photo catalytic for MB degradation. • The nano hybrid exhibit excellent photo catalytic efficiency of 99.34 % in merely 60 min of experiment. • The catalysts were magnetically separable indicating their stability, and reusability. Over the years, there has been a surge in interest in the use of photocatalysts for the removal of organic pollutants in wastewater. In this work, we report the successful fabrication of magnetic Co 0.75 Zn 0.25 Fe 2 O 4 /g-C 3 N 4 nano hybrids for wastewater treatment. The produced photo catalysts were used to decompose methylene blue dye. SEM, elemental mapping, XPS, Raman, and UV–visible spectroscopy were used to validate the successful creation of the nanohybrid structure. The catalysts were synthesized in three different ferrite/graphitic carbon nitride ratios and employed for the optimization of maximum photo degradation efficiency against methylene blue dye. The optimal A1 (50%Co 0.75 Zn 0.25 Fe 2 O 4 /50%g-C 3 N 4) photo catalyst exhibited excellent degradation efficiency of 99.34% for methylene blue removal in 60 min experiment. The integration of both components in a nanohybrid favours charge separation with efficient Z-scheme charge transport via redox mediators. Scavenging investigations provide credence to superoxide and hydroxyl radicals as reactive species in MB breakdown. An appropriate mechanism with outstanding stability and confirmed reusability for the envisaged photo catalyst has been described. [ABSTRACT FROM AUTHOR]

Currently, the photocatalytic nanomaterials performing under solar radiation have gained worldwide attentions due to increasing environmental deterioration. For utilizing the sunlight for degradation of emerging pollutants it is important to develop visible active photocatalysts. This laboratory scale work reports magnetic and optically active nano-photocatalyst Fe x Zn 1−x O(x = 0.01, 0.03, 0.05) synthesized by solution combustion method. High resolution transmission microscopy suggests a slight degradation in the crystallite structure with Fe doping. X-ray photoelectron spectroscopy analysis shows the presence of intrinsic defects in the crystal structure. Zn resides in +2 and and Fe in +3 oxidation state. Optical band gap studies were made with band structure for each doped sample. The photoctalytic activity of the samples was tested by solar degradation of noxious pollutant Bisphenol A. 99.1% of bisphenol was degraded in 90min in presence of Fe 0.03 Zn 0.97 O under synergistic adsorption and photocatalysis. The results were analyzed in terms of total organic carbon, chemical oxygen demand, effect of scavengers, gas chromatography-mass spectrometry and reusability. In presence of Fe 0.03 Zn 0.97 O, 45.3% of total organic carbon was removed and chemical oxygen demand was reduced to 11.2%. A possible mechanism with structures of the intermediates has been given. Effect of scavengers reveal that hydroxyl radicals are major reactive oxygen species involved which is also supported by the band edge positions. The research work promises to design highly photo-active tuneable magnetic photocatalysts for solar powered degradation of contaminants of emerging concern with a simple and cost-effective approach. [ABSTRACT FROM AUTHOR]

In this research work we report synthesis of g-C 3 N 4 /FeVO 4 (CI) and g-C 3 N 4 /FeVO 4 /Fe@NH 2 -Biochar (CIB) nano-hetero assemblies for removal of methyl paraben (MeP) and 2-cholrophenol (2-CP) via adsorption, photocatalysis and photo-ozonation. CI and CIB have been characterized by FT-IR, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), UV–Vis spectroscopy, photoluminescence (PL), vibrating sample magnetometry (VSM), Brauner-Emmet Teller surface area analyzer (BET). CIB shows good photocatalytic activity owing to higher specific area, nanosheet porous structure, stability, broader solar spectrum response and reduced charge carriers recombination. Fe@NH 2 -biochar facilitates the degradation via high adsorption capability due to reduced recombination, better charge separation, adsorption and acting of biochar as sink of electrons. The CIB photocatalytic system was tested under three experimental conditions for photodegradation of MeP and 2-CP; adsorption followed by photo-degradation (AP); simultaneous adsorption and photocatalysis (SAP); SAP + O 3 . An apparent synergism between adsorption, photocatalysis and photo-ozonation brings out excellent and promising results. 98.4% of MeP and 90.7% of CP degradation was achieved under simultaneous adsorption and photocatalysis in presence of CIB. The results were analyzed in terms of reaction kinetics, adsorption isotherms, scavenger effect, liquid chromatography-mass spectrometry (LC-MS), Total Organic Carbon (TOC) analysis and cytotoxicity analysis of treated water. An efficient TOC removal 74.2 & 73.9% for MeP and 2-CP were respectively achieved under SAP + O 3 +CIB photocatalysis system. Degradation pathways have been proposed for degradation of MeP and CP thorough photo-degradation and photo-ozonation. The cyto-toxicity studies on Human peripheral blood lymphocytes provide a reference for removal of noxious pollutants in real systems. This experimental work paves a way to design tuneable simple junctions for photocatalytic applications by utilizing various experimental protocols. [ABSTRACT FROM AUTHOR]