Exceptional Photocatalytic Activity Research Articles

Nano tumbleweed-like tungsten disulfide as a viable surrogate for platinum counter electrodes in dye-sensitized solar cells

Tungsten disulfide (WS2), a notable member of the transition metal dichalcogenides family, has emerged as a promising candidate for energy storage and conversion applications. In this study, WS2 was synthesized via a hydrothermal method using sodium tungstate and thiourea as precursor materials, with hydroxylamine hydrochloride as the reducing agent and cetyl trimethyl ammonium bromide as a surfactant. The primary objective was to develop a cost-effective, easily synthesized, and scalable material capable of replacing platinum (Pt) in dye-sensitized solar cells (DSSCs), where Pt is both prohibitively expensive and scarce. Characterization of the synthesized WS2 was conducted through a range of physical analyses, including SEM, TEM, XRD, EDAX, FTIR, and Raman spectroscopy, which provided compelling evidence for the formation of a unique nano-tumbleweed-like structure of WS2. When used as a counter electrode (CE), the synthesized WS2 exhibited exceptional photocatalytic activity, resulting in a commendable power conversion efficiency (PCE) of 12.06 % when coupled with fluorine-doped tin oxide (FTO) plates coated with TiO2 as the photoanode, N719 as the dye, and Iˉ/I3ˉ as the liquid electrolyte. Additionally, the fabricated device underwent comprehensive electrical characterization, including cyclic voltammetry (CV), current-voltage (IV) measurements, electrochemical impedance spectroscopy (EIS), and Tafel analysis, revealing properties similar to those of Pt counter electrodes. Notably, WS2 demonstrated an open-circuit potential of 852 mV and a short-circuit current density of 28 mA/cm2, accompanied by a fill factor of 0.43 and a commendable lifetime of 15.92 ms.

A new 2,5-bis(pyrid-4-yl)pyridine based Mn(II) metal–organic framework on photochemically antibiotic degradation

The synthesis of a new Mn(II)-based metal–organic framework (MOF), denoted as [Mn3(bpyp)3(HCOO)4(H2O)2·2NO3–·H2O]n(1) (bpyp = 2,5-bis(pyrid-4-yl)pyridine) was confirmed by single-crystal X-ray diffraction (XRD), UV–visible, Fourier-transform infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA). 1 exhibits a new 3D porous network with a (3,4,5)-connected topology. The photocatalytic degradation capability of 1 was investigated against various antibiotics, including dimethonidazole (DTZ), nitrofurazone (NFZ), nitrofurantoin (NFT), tinidazole (TDZ), and furazolidone (FZD). 1 exhibited exceptional photocatalytic activity against NFT, with a dosage of 5 mg/L resulting in a remarkable degradation efficiency of 96.81 % for 40 ppm NFT. Furthermore, a proposed photodegradation mechanism was investigated through radical trapping experiments, providing insights into the underlying pathways involved in the photocatalytic degradation process.

Ruthenium Single Atomic Sites Surrounding the Support Pit with Exceptional Photocatalytic Activity.

Single-metal atomic sites and vacancies can accelerate the transfer of photogenerated electrons and enhance photocatalytic performance in photocatalysis. In this study, a series of nickel hydroxide nanoboards (Ni(OH)x NBs) with different loadings of single-atomic Ru sites (w-SA-Ru/Ni(OH)x) were synthesized via a photoreduction strategy. In such catalysts, single-atomic Ru sites are anchored to the vacancies surrounding the pits. Notably, the SA-Ru/Ni(OH)x with 0.60 wt % Ru loading (0.60-SA-Ru/Ni(OH)x) exhibits the highest catalytic performance (27.6 mmol g-1 h-1) during the photocatalytic reduction of CO2 (CO2RR). Either superfluous (0.64 wt %, 18.9 mmol g-1 h-1; 3.35 wt %, 9.4 mmol-1 h-1) or scarce (0.06 wt %, 15.8 mmol g-1 h-1; 0.29 wt %, 21.95 mmol g-1 h-1; 0.58 wt %, 23.4 mmol g-1 h-1) of Ru sites have negative effect on its catalytic properties. Density functional theory (DFT) calculations combined with experimental results revealed that CO2 can be adsorbed in the pits; single-atomic Ru sites can help with the conversion of as-adsorbed CO2 and lower the energy of *COOH formation accelerating the reaction; the excessive single-atomic Ru sites occupy vacancies that retard the completion of CO2RR.

Ruthenium Single Atomic Sites Surrounding the Support Pit with Exceptional Photocatalytic Activity

AbstractSingle‐metal atomic sites and vacancies can accelerate the transfer of photogenerated electrons and enhance photocatalytic performance in photocatalysis. In this study, a series of nickel hydroxide nanoboards (Ni(OH)x NBs) with different loadings of single‐atomic Ru sites (w‐SA‐Ru/Ni(OH)x) were synthesized via a photoreduction strategy. In such catalysts, single‐atomic Ru sites are anchored to the vacancies surrounding the pits. Notably, the SA‐Ru/Ni(OH)x with 0.60 wt % Ru loading (0.60‐SA‐Ru/Ni(OH)x) exhibits the highest catalytic performance (27.6 mmol g−1 h−1) during the photocatalytic reduction of CO2 (CO2RR). Either superfluous (0.64 wt %, 18.9 mmol g−1 h−1; 3.35 wt %, 9.4 mmol−1 h−1) or scarce (0.06 wt %, 15.8 mmol g−1 h−1; 0.29 wt %, 21.95 mmol g−1 h−1; 0.58 wt %, 23.4 mmol g−1 h−1) of Ru sites have negative effect on its catalytic properties. Density functional theory (DFT) calculations combined with experimental results revealed that CO2 can be adsorbed in the pits; single‐atomic Ru sites can help with the conversion of as‐adsorbed CO2 and lower the energy of *COOH formation accelerating the reaction; the excessive single‐atomic Ru sites occupy vacancies that retard the completion of CO2RR.

Synergistic interfacial engineering of a S-scheme ZnO/In2S3 photocatalyst with S−O covalent bonds: A dual-functional advancement for tetracycline hydrochloride degradation and H2 evolution

Efficient interfacial charge transfer and robust interface interactions are crucial to achieve superior spatial separation of carriers and develop advanced heterogeneous photocatalysts. This study describes the synthesis of a novel S-scheme heterojunction of ZnO/In2S3, with S−O covalent bonds, achieved through a hydrothermal method. The optimized heterojunction shows exceptional photocatalytic activity, achieving a H2 generation rate of 2488 μmol g−1 h−1 and a degradation efficiency of 86 % for tetracycline hydrochloride (TCH) within 2 h. These values surpass those of In2S3 alone by 35 and 1.4 times, respectively. Various techniques, including electron spin resonance, X-ray photoelectron spectroscopy, Kelvin probe force microscopy and density functional theory calculations confirm the S-scheme heterojunction. The establishment of a chemical S−O bond between In2S3 and ZnO facilitates an atomic level interfacial pathway, enabling efficient transportation of interfacial electrons.

Z-scheme heterojunction g-C3N4-TiO2 reinforced chitosan/poly(vinyl alcohol) film: Efficient and recyclable for fruit packaging

Nanoparticles-loaded bio-based polymers have emerged as a sustainable substitute to traditional oil-based packaging materials, addressing the challenges of limited recyclability and significant environmental impact. However, the functionality and efficiency of nanoparticles have a significant impact on the application of bio-based composite films. Herein, graphitic carbon nitride (g-C3N4) and titanium dioxide (TiO2) coupled photocatalyst (g-C3N4-TiO2) was prepared by one-step calcination and introduced into chitosan (CS) and polyvinyl alcohol (PVA) solution to fabricate g-C3N4-TiO2/CS/PVA green renewable composite film via solution casting method. The results demonstrated the successful preparation of a Z-scheme heterojunction g-C3N4-TiO2 with exceptional photocatalytic activity. Furthermore, the incorporation of heterojunction enhanced mechanical properties, water barrier, and ultraviolet (UV) resistance properties of the fresh-keeping film. The g-C3N4-TiO2/CS/PVA composite film exhibited superior photocatalytic antibacterial preservation efficacy on strawberries under LED light, with a prolonged preservation time of up to 120 h, when compared to other films such as polyethylene (PE), CS/PVA, g-C3N4/CS/PVA, and TiO2/CS/PVA. In addition, the composite film has good recyclability and renewability. This work is expected to have great potential for low-cost fruit preservation and sustainable packaging, which also contributes to environmental protection.

Syntheses and photochemically antibiotic degradation of two Co(II)-based coordination polymers

Two new Co(II)-based coordination polymers (CPs), designated as [Co2(bbp)4(1,3-bdc)4]n(1) and [Co(bbp)3(NO3)2(H2O)]n(2) (bbp = 3,5-bis(benzoimidazo-1-ly) pyridine; 1,3-H2bdc = 1,3-benzenedicarboxy acid), were synthesized using a dual ligand approach. The characterization of these CPs involved single- crystal -XRD, UV–visible, FT-IR, and TGA analysis. Both CPs 1 and 2 exhibit a distorted octahedral geometry. Both 1 and 2 show a 1D ladder chain, and this chain-like structure undergoes further development into a more intricate two-dimensional (2D) supramolecular network. The thermal stability analysis revealed that 1 and 2 are stable at temperatures of 119 °C and 286 °C, respectively, with no significant mass loss. Notably, both CPs displayed semiconducting properties. The photocatalytic degradation capabilities of CPs 1 and 2 were investigated against antibiotics such as metronidazole (MDZ), Tinidazole (TDZ), ornidazole (ODZ), and furazolidone (FZD). CP 1 exhibits exceptional photocatalytic activity against FZD. A dosage of 5 mg/L of CP 1 resulted in a remarkable degradation efficiency of 92.2 % for 40 ppm FZD. Additionally, a proposed photodegradation mechanism was investigated through radical trapping experiments.

Enhanced solar light-induced performance of a step-scheme heterojunction nanostructure (C3N4/ZrO2) for mixed dye degradation and methanol oxidation

This study focuses on the high demand for innovative nanostructured materials with boosted photocatalytic performance for the degradation of organic pollutants and oxidation of organic compounds. A nanostructure consisting of graphitic carbon nitride (C3N4) and zirconium oxide (ZrO2) denoted as C3N4/ZrO was synthesized via direct thermal pyrolysis. A comprehensive array of characterization techniques (XRD, FESEM, HRTEM and UV-DRs analysis) was utilized for a detailed analysis of the prepared photocatalysts. The photoactivity of the C3N4/ZrO nanostructure was explored by the photocatalytic degradation of a mixture of dyes (Rh B + CV), and methanol oxidation reaction and compared with those of pristine C3N4 and ZrO2. The photoactivity of C3N4/ZrO for degrading the mixed dye under simulated solar light was 97% higher than those of pristine C3N4 (88%) and ZrO2 (31%). The C3N4/ZrO nanostructure, functioning as a step-scheme heterojunction, demonstrated superior photocatalytic performance due to enhanced charge transport facilitated by robust interfacial contact between C3N4 and ZrO2. This enhanced photodegradation efficiency, reaching 97%, establishes a foundation for the development of heterojunction catalysts with exceptional photocatalytic activities. Furthermore, the methanol oxidation activity of the C3N4/ZrO nanostructure was exceptionally high, yielding a 138.25 mA/cm2 current density at a 2 M methanol. The proposed material has a high application potential for mitigating pollution and energy issues.

Sunlight-assisted green synthesis of gold nanocubes using horsetail leaf extract: A highly selective colorimetric sensor for Pb2+, photocatalytic and antimicrobial agent

This work aims to establish a novel approach for the selective synthesis of gold nanoparticles (Au NPs) with defined shape and size as well as excellent colloidal stability via a facile and environmentally friendly manner. The polar extract from the leaves of the plant E. diffusum (EDLE), also known as horsetail, was used to synthesize gold NPs (EDLE@Au NPs). Fourier-transform infrared (FTIR) and UV–visible spectroscopy, scanning electron microscopy-energy dispersive X-rays (SEM-EDX), PXRD, dynamic light scattering (DLS), and zeta potential (ZP) were used to characterize as-synthesized EDLE@Au NPs. The SEM imaging revealed the cubic shape of EDLE@Au NPs. Interestingly, EDLE@Au NPs interacted with different metal ions, and a shift in the LSPR band to a higher wavelength was observed only in the case of Pb2+ ions. This provided a basis for using the EDLE@Au NPs as a selective colorimetric sensor for Pb2+ ions. A linear range of 20–350 µM and a limit of detection of 4.4 µM for Pb2+ detection was achieved. To elucidate the sensing mechanism, DLS and zeta potential analyses were carried out after addition of Pb2+. A significant decrease in the zeta potential along with an increase in the particle size of the Au NPs was observed after the addition of Pb2+, suggesting the aggregation of the nanoparticles. Further, the results of the antimicrobial study showed that EDLE@Au NPs were active against both gram-positive and gram-negative bacteria. An exceptional photocatalytic activity with 96.5% degradation efficiency of EDLE@Au NPs was examined against methylene blue dye.

Dual Function of Naphthalenediimide Supramolecular Photocatalyst with Giant Internal Electric Field for Efficient Hydrogen and Oxygen Evolution.

Organic supramolecular photocatalysts have garnered widespread attention due to their adjustable structure and exceptional photocatalytic activity. Herein, a novel bis-dicarboxyphenyl-substituent naphthalenediimide self-assembly supramolecular photocatalyst (SA-NDI-BCOOH) with efficient dual-functional photocatalytic performance is successfully constructed. The large molecular dipole moment and short-range ordered stacking structure of SA-NDI-BCOOH synergistically create a giant internal electric field (IEF), resulting in a remarkable 6.7-fold increase in its charge separation efficiency. Additionally, the tetracarboxylic structure of SA-NDI-BCOOH greatly enhances its hydrophilicity. Thus, SA-NDI-BCOOH demonstrates efficient dual-functional activity for photocatalytic hydrogen and oxygen evolution, with rates of 372.8 and 3.8µmol h-1 , respectively. Meanwhile, a notable apparent quantum efficiency of 10.86% at 400nm for hydrogen evolution is achieved, prominently surpassing many reported supramolecular photocatalysts. More importantly, with the help of dual co-catalysts, it exhibits photocatalytic overall water splitting activity with H2 and O2 evolution rates of 3.2 and 1.6µmol h-1 . Briefly, this work sheds light on enhancing the IEF by controlling the molecular polarity and stacking structure to dramatically improve the photocatalytic performance of supramolecular materials.

In-situ growing Ni2P on CdS@g-C3N4 composites for highly efficient synergistically photocatalytic H2 evolution and antibiotic degradation

Achieving simultaneous photocatalytic H2 evolution and antibiotic degradation is ideal but challenging. Herein, IS-Ni2P/CdS/CN ternary composites was elaborately constructed by electrostatic self-assembly followed by in-situ growth of Ni2P method. The IS-Ni2P/CdS/CN exhibit extremely high H2 yield and achieve synergistic degradation of multiple antibiotic contaminants (323 μmol g−1h−1 for H2 yield and 72 % for tetracycline hydrochloride synergistic degradation). Interestingly, for the synergistic mechanism, it is found that antibiotic molecules can serve as electron donors to promote the separation of carriers, thus remarkably improving H2 yield. More notably, the electron-donating capacity of antibiotic molecules dictates the synergistic efficiency, that is, the stronger the electron-donating capacity of antibiotic molecules, the more favorable it is for enhancing synergistic efficiency. Besides, experimental and DFT calculation demonstrate that the exceptional photocatalytic activity of IS-Ni2P/CdS/CN is ascribed to the combined effect of the induced internal electric field, and the improved interfacial contact by the in-situ grown Ni2P cocatalyst, thus substantially accelerating carriers transport. Our work provides an idea for simultaneous photocatalytic H2 evolution and pollutants degradation.

A robust bio-source mediated CeO2 – SnS2 quantum dots @Oryza sativa var. biochar, photo-adsorbent for removal of Baszol Violet 57L dye from aqueous discharge: Development, materialistic analyses, and its application

This research aims to develop an entirely novel kind of photocatalytic adsorbent, known as integrated photocatalytic adsorbent, using a hydrothermal process that is environmentally friendly. This method utilizes an extract derived from Tulsi (Osmium Tenuiflorum) leaves as a stabilizing and capping agent. The purpose of the synthesized material is to effectively remove Baszol Violet 57L (BV57L) dye from wastewater. CeO2, was combined with a semiconductor photocatalyst, SnS2, to create a composite photocatalyst. This choice was made based on the exceptional photocatalytic activity of the catalyst when supported on rice straw (Oryza sativa var.) biochar, specifically for the adsorption of selected pollutants. The study investigated the integrated photocatalytic and adsorption (IPA) characteristics of the fabricated material, using BV57L dye as a representative emerging pollutant commonly found in wastewater. From the Tauc's plots of final nanohybrid (CSB) it was calculated that the energy band gap of CSB was around ∼2.7 eV. The novelty of the current study lies in its examination of the synergistic adsorption and photocatalytic properties under diverse reaction conditions that replicate real-world wastewater conditions. The inclusion of biochar in the CeO2-SnS2 nanocomposite yielded a discernible decline in the rate of charge recombination, thereby causing a notable enhancement in the photocatalytic efficiency of the nanocomposite.The adsorption data confirmed with the Langmuir isotherm model with maximum adsorption capacity of 333.58 mg g−1 at BV57L concentration of 350 mg L−1 under optimal conditions, suggesting the occurrence of monolayer chemosorption and following pseudo-second-order rate kinetics with rate constant of 1.59 × 10−5 g mg−1 min−1. The process of photodegradation exhibits kinetics that can be approximated as pseudo-first-order, with the BV57L dye displaying a significant constant of 0.0731 min−1. A simultaneously processed adsorption and photodegradation model was found to achieve an overall BV57L removal efficiency of 97.26 % within a 90-min timeframe. Additionally, impact of pH, reusability-stability of catalyst, and a photodegradation mechanism for the BV57L removal is also clearly presented. The combination of visible light-induced photodegradation activity in CeO2-SnS2 nanocomposite and the adsorption capability of biochar leads to the highly effective removal of pollutants from the liquid phase.

CuInSe2 nanoplatelets decorated CdS nanosheets as 2D-2D S-scheme photocatalyst for photocatalytic H2 generation coupled with benzyl alcohol oxidation and microplastic degradation

In this work, a novel 2D layered heterojunction for various photocatalytic reactions is constructed by hybridizing CdS nanosheets and CuInSe2 nanoplatelets. By adjusting CuInSe2 content, the CdS-16% CuInSe2 sample displays a visible-light-induced H2 production rate of 4382 μmol g−1 h−1, approximately 7.5 times higher than pristine CdS. Furthermore, CdS-16% CuInSe2 demonstrates exceptional photocatalytic activity in H2 evolution simultaneous benzyl alcohol (BA) oxidation and polyethylene terephthalate (PET) degradation. The superior photocatalytic activity is ascribed to the unique S-scheme heterojunction and 2D-2D CdS–CuInSe2 layered heterostructures that effectively separate photoinduced charge carriers and provide appropriate interfacial band structures. The photocatalytic mechanism is thoroughly examined through experiments and density functional theory calculations. This work offers a valuable platform to develop innovative layered photocatalysts that are highly effective for a wide range of photocatalytic reactions.

La3+ substitution-adjusted magnetic and optical properties with enhanced photocatalytic activity and stability of copper zinc nickel ferrites for wastewater treatment applications

Copper-zinc-nickel (Cu–Zn–Ni) ferrite nanoparticles are used for wastewater treatment technology. However, low degradation efficiency and stability are two main issues that make them unsuitable for actual production needs. In this paper, the citrate-nitrate auto-combustion method was applied for the formation of Cu0.5Zn0.25Ni0.25LaxFe2–xO4; (0≤x≤0.1; step 0.02) (CZNL) nanoferrites. Although the substitution process entails the replacement of a small ion with a larger one, the lattice constant and crystallite size does not exhibit a consistent incremental pattern. This behavior is justified and discussed. The size of all the CZNL ferrite nanoparticles is in the range of 8–12 nm, and the lattice constant is in the range of 8.6230 to 8.4865 nm. The morphological analysis conducted using field emission-scanning electron microscopy (FE-SEM) reveals that the CZNL exhibits agglomerated spherical morphology. The energy dispersive X-ray spectrameter (EDAX) analysis was employed to confirm the elemental composition of CZNL nanoferrites. Since the process entails the substitution of Fe3+ magnetic ions with non-magnetic ions La3+, the magnetic parameters of CZNL nanoferrites show a general decreasing trend as predicted. At 20 K, saturation magnetization Ms shows an overall drop in its values from 59.302 emu/g at x = 0.0–41.295 emu/g at x = 0.1, the smallest value of 37.87 emu/g is recorded at x = 0.06. the highest coercivity (Hc = 125.9 Oe) and remanence (Mr = 13.32 emu/g) are recorded for x = 0.08 and x = 0.04 nanoferrite, respectvely. The band gap of all the CZNL nanoferrites was determined using the Kubelka–Munk function and Tauc plot for direct permitted transitions. La doping modifies the band gap (within 1.86–1.75 eV), increases light absorption, induces efficient e/h separation and charge migration to Cu0.5Zn0.25Ni0.25LaxFe2–xO4 surfaces. The nanoferrite Cu0.5Zn0.25Ni0.25La0.06Fe1.94O4 achieves a degradation efficiency of 97.3% for methylene blue (MB) dye removal after just 60 min. After five recycling processes, the nanocatalyst Cu0.5Zn0.25Ni0.25La0.06Fe1.94O4 is degraded by 95.83%, resulting in a negligible 1.51% decrease in photocatalytic activity efficiency. The new Cu0.5Zn0.25Ni0.25La0.06Fe1.94O4 has exceptional photocatalytic activity and remarkable stability, making it a promising candidate for applications in wastewater treatment.

Temperature-dependent heterojunction ternary nanocomposite: Assessing photocatalytic and antibacterial applications

Heterojunction nanocomposites (ZnO:NiO:CuO) were synthesized via a hydrothermal method and annealed at three different temperatures (400 °C, 600 °C, and 800 °C). The structural, optical, and electrical properties were examined by employing XRD, SEM, UV–Vis, FTIR, and LCR meter techniques to investigate the effects of annealing. Increasing the annealing temperature resulted in the nanocomposites (NCPs) exhibiting enhanced crystallinity, purity, optical properties, and improved electrical and dielectric behavior. The calculated crystalline sizes (Debye-Scherrer method) of the NCPs were determined to be 21, 26 and 34 nm for annealing temperature 400 °C, 600 °C, and 800 °C, respectively. The calculated bandgaps of synthesized samples were found in the range of 2.92-2.55 eV. This temperature-dependent annealing process notably influenced particle size, morphology, band-gap characteristics, and photocatalytic efficiency. EDX analysis affirmed the sample purity, with elemental peaks of Zn, Cu, Ni, and O. These NCPs demonstrated exceptional photocatalytic activity against various dyes solutions (Methyl orange (MO), Methylene Blue (MB), and mixed solution of dyes) under sunlight and also showed good antibacterial properties assessed by the disc diffusion method. Notably, the nanocomposite annealed at 400 °C exhibited a particularly high degradation efficiency by degrading 96% MB and 91% MO in just 90 min under sunlight.

Biosynthesis of ZnO/Ag nanocomposites heterostructure for efficient photocatalytic degradation of antibiotics and synthetic dyes

Abstract This study addresses the pressing issue of environmental pollution caused by antibiotics and synthetic dyes in aquatic ecosystems, presenting a novel approach for their efficient photocatalytic degradation. Zinc oxide (ZnO)-based nanoscale photocatalysts, including ZnO nanoparticles (NPs) and ZnO/Ag nanocomposite heterostructure (NCH), were synthesized through an innovative and eco-friendly method utilizing an extract derived from discarded lemon peels as a biogenic reducing agent. The synthesized materials were extensively characterized through UV spectrophotometry, X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). The results confirmed the different morphologies of ZnO NPs and ZnO/Ag NCH, with average sizes of 20 nm and 42 nm, respectively. Notably, the ZnO NPs and ZnO/Ag NCH exhibited optical bandgap energies of 3.2 eV and 2.85 eV, respectively, signifying their potential as efficient photocatalysts. Under natural sunlight irradiation, these materials demonstrated exceptional photocatalytic activity, achieving a remarkable 98.8 % degradation rate for metronidazole and 90 % for ciprofloxacin in just 12 min. Furthermore, the ZnO NPs effectively removed 84 % of Toluidine Blue and 77 % of Congo red after 120 min, while ZnO/Ag NCH enhanced degradation rates to approximately 90.5 % for Toluidine Blue and 86 % for Congo Red. This research highlights the significant physicochemical properties and novel synthesis methods employed, positioning these sustainable nanomaterials as promising solutions for mitigating environmental pollution effectively.

Unravelling the enhanced rifampicin photocatalytic degradation over green-synthesized SrO2@SnIn4S8 p-n heterojunction: Pathway, toxicity evaluation and mechanistic insights

In recent years, the discharge of pharmaceutical drugs into aquatic ecosystems has become a growing concern, posing a significant threat to aquatic life. In response to this environmental challenge, advanced oxidation processes have gained prominence in wastewater treatment due to their efficacy in eliminating pharmaceutical pollutants and their potential for reusability. In this study, we have fabricated SnIn4S8 coupled SrO2 nano-heterojunction (NH) using a greener co-precipitation approach using leaf extract derived from Acaphyla wilkesiana. The resulting NH exhibited exceptional photocatalytic activity against rifampicin (RIF), achieving a remarkable 97.4% degradation under visible light, surpassing the performance of its individual components. The morphological characteristics of the NH were thoroughly analyzed through SEM, TEM, XRD, and XPS techniques, while EIS, DRS, and BET techniques provided valuable insights into its photocatalytic and optical properties. Furthermore, radical scavenging assays and ESR analysis identified hydroxyl radicals (•OH) and superoxide radicals (O2•-) were the species contributing to the visible light-driven photocatalytic degradation. The study also elucidated the potential degradation pathways and intermediates of RIF through GC-MS analysis. Additionally, the toxicity of the produced intermediates was assessed using the ECOSAR model. The findings have significant implications for the treatment of pharmaceutical pollutants and underscore the importance of eco-friendly synthesis methods in addressing environmental challenges.

Enhancing Photocatalytic CO2 Conversion through Oxygen-Vacancy-Mediated Topological Phase Transition.

Weak adsorption of gas reactants and strong binding of intermediates present a significant challenge for most transition metal oxides, particularly in the realm of CO2 photoreduction. Herein, we demonstrate that the adsorption can be fine-tuned by phase engineering of oxide catalysts. An oxygen vacancy mediated topological phase transition in Ni-Co oxide nanowires, supported on a hierarchical graphene aerogel (GA), is observed from a spinel phase to a rock-salt phase. Such in situ phase transition empowers the Ni-Co oxide catalyst with a strong internal electric field and the attainment of abundant oxygen vacancies. Among a series of catalysts, the in situ transformed spinel/rock-salt heterojunction supported on GA stands out for an exceptional photocatalytic CO2 reduction activity and selectivity, yielding an impressive CO production rate of 12.5 mmol g-1 h-1 and high selectivity of 96.5 %. This remarkable performance is a result of the robust interfacial coupling between two topological phases that optimizes the electronic structures through directional charge transfer across interfaces. The phase transition process induces more Co2+ in octahedral site, which can effectively enhance the Co-O covalency. This synergistic effect balances the surface activation of CO2 molecules and desorption of reaction intermediates, thereby lowering the energetic barrier of the rate-limiting step.

Green synthesis of tellurium-doped SnO2 nanoparticles with sulfurized g-C3 N4 : Insights into methylene blue photodegradation and antibacterial capability.

The construction of SnO2 nanoparticles (NPs), specifically Te-doped SnO2 NPs, using a simple and economical co-precipitation technique has been thoroughly described in this work. NH3 served as the reducing agent in this procedure, whilst polyethylene glycol served as the capping agent. The primary goals of our work were to investigate the physicochemical properties of the synthesized SnO2 NPs and assess their potential use as antibacterial agents and photocatalysts. Scanning electron microscopy-energy dispersive X-ray, ultraviolet light, Fourier transform infrared spectroscopy, X-ray diffraction (XRD), and other analytical techniques were used to thoroughly analyze the NPs. Based on the full width at half maximum of the most noticeable peaks in the XRD spectrum, the Debye-Scherrer equation was used to calculate the crystallite sizes, which indicated the presence of a single tetragonal SnO2 phase. Particularly noteworthy was the exceptional photocatalytic activity of graphene-assisted Te-doped SnO2 NPs, achieving an impressive decomposition efficiency of up to 98% in the photo-oxidation of methylene blue. Furthermore, our investigation delved into the antibacterial attributes of the synthesized SnO2 NPs against Escherichia coli and Staphylococcus aureus, demonstrating inhibitory effects on both bacteria strains. This suggests potential applications for these NPs in various environmental and medical contexts.

Enhancing Photocatalytic CO2 Conversion through Oxygen‐Vacancy‐Mediated Topological Phase Transition

Weak adsorption of gas reactants and strong binding of intermediates present a significant challenge for most transition metal oxides, particularly in the realm of CO2 photoreduction. Herein, we demonstrate that the adsorption can be fine‐tuned by phase engineering of oxide catalysts. An oxygen vacancy mediated topological phase transition in Ni‐Co oxide nanowires, supported on a hierarchical graphene aerogel (GA), is observed from a spinel phase to a rock‐salt phase. Such in‐situ phase transition empowers the Ni‐Co oxide catalyst with a strong internal electric field and the attainment of abundant oxygen vacancies. Among a series of catalysts, the in‐situ transformed spinel/rock‐salt heterojunction supported on GA stands out for an exceptional photocatalytic CO2 reduction activity and selectivity, yielding an impressive CO production rate of 12.5 mmol g‐1h‐1 and high selectivity of 96.5%. This remarkable performance is a result of the robust interfacial coupling between two topological phases that optimizes the electronic structures through directional charge transfer across interfaces. The phase transition process induces more Co2+ in octahedral site, which can effectively enhance the Co‐O covalency. This synergistic effect balances the surface activation of CO2 molecules and desorption of reaction intermediates, thereby lowering the energetic barrier of the rate‐limiting step.