Catalytic Degradation Of Organic Dyes Research Articles

Enhanced catalytic degradation of organic dye by Sn1-xLaxO2 nanoparticles under UV light for wastewater treatment

Effectively eliminating dyes and heavy metals from wastewater, without secondary contamination and with easy recovery, is a significant challenge. To address this, SnO2-based photocatalysts were fabricated using a straightforward sol–gel method, aiming to achieve high-value reutilization and environmental protection. Utilizing XRD, FTIR, and HRTEM, the investigation has conclusively confirmed the emergence of nanoparticles (NPs) through rigorous analysis and observation techniques. Raman, XPS, and PL spectroscopy probed electronic, optical properties, and lattice defects, offering comprehensive insights into material characteristics. Specific BET surface areas were observed to be 17.72 and 39.64 m2/g for 0 % and 5 % La samples. The introduction of dopant La to the SnO2 lattice resulted in enhanced optical properties, demonstrated by a significant red shift. La-SnO2 nanoparticles demonstrated remarkable catalytic efficacy, degrading 94 % of RB dye solution under 60 min of UV light exposure. Even after four cycles, the catalytic degradation activity remained high at 87 %, showcasing excellent structural stability. Enhanced adsorption capacity and effective separation of electron-hole pairs under light contribute to this improvement. Moreover, the study delved into defect-based room temperature ferromagnetism (RTFM) by examining the formation of a novel network, such as La3+-O-Sn4+. The results highlight the potential of these composites doped photocatalysts as effective materials for degrading harmful organic pollutants in wastewater treatment and for their application in spintronic devices. The present study aims to characterize the structural, magnetic, and optical attributes of La-doped SnO2 nanoparticles.

Catalytic Degradation Efficacy of Silver Nanoparticles Fabricated Using Actinidia deliciosa Peel Extract

The preparation of metallic nanoparticles using green synthetic approaches and its application toward the efficient degradation of environmentally hazardous dyes constitutes an attractive alternative to currently employed methods. In the current report, the green synthesis of silver nanoparticles (AgNPs) was successfully achieved using Actinidia deliciosa (kiwifruit) peel aqueous extract as a bioreducing agent under optimized synthesis conditions. The experimental parameters were optimized in terms of reactant ratio, reaction temperature, and reaction time. The biogenic nanoparticles exhibited SPR absorption band at λmax 480 nm. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images revealed quasispherical monodisperse nanoparticles which were 36 nm in diameter. The hydrodynamic diameter of the nanoparticles was 106 nm as determined by dynamic light scattering, and the highly negative ζ-potential (−34 mV) supported its superior colloidal stability. Energy dispersive X-ray confirmed that silver is a major constituent of the nanoparticles. X-ray diffraction (XRD) diffractograms confirmed the crystallinity of the nanoparticles and its face-centered cubic (fcc) lattice structure. The functional groups in the plant’s phytochemicals facilitating the reduction of Ag+ ions and stabilization of the formed AgNPs were identified by fourier transform infrared (FTIR) spectroscopy. In specific, the bands in the FTIR spectra at 3,412, 1,618, 1,419, and 1,237 cm−1 suggested the presence of phenolic compounds. Phytochemical analysis by colorimetric assays revealed that the kiwifruit peel extract was rich in phenolic compounds. When evaluated in the catalytic degradation of organic dyes, the biosynthesized AgNPs induced instant and complete discoloration of the methylene blue dye when 1.6 mg of nanoparticles was used. At a lower dose of AgNPs (0.4 mg), 80% degradation of the dye occurred after 3 hr of treatment. The degradation reaction followed second-order kinetics with a rate constant of 0.01083 mM−1s−1. The current study highlights the immense potential of the prepared nanoparticles as efficient catalysts for the degradation of hazardous organic dyes such as methylene blue and presents an intriguing argument for investigating the catalytic efficiency of the biogenic AgNPs for the degradation of other structurally different dye pollutants.

Highly efficient catalytic degradation of organic dyes using iron nanoparticles synthesized with Vernonia Amygdalina leaf extract

Today, nanoscience explores the potential of nanoparticles due to their extraordinary properties compared to bulk materials. The synthesis of metal nanoparticles using plant extracts is a very promising method for environmental remediation, which gets global attention due to pollution-led global warming. In the present study, iron nanoparticles (FeNPs) were successfully synthesized by the green method using Vernonia amygdalina plant leaf extract as a natural reducing and capping agent. Biosynthesized FeNPs were characterized with different analytical techniques such as UV–visible, FT-IR, XRD, and SEM. The analysis revealed the formation of amorphous FeNPs with an irregular morphology and non-uniform distribution in size and shape. The average particle size was approximately 2.31 µm. According to the catalytic degradation investigation, the FeNPs produced via the green approach are highly effective in breaking down both CV and MB into non-toxic products, with a maximum degradation efficiency of 97.47% and 94.22%, respectively, when the right conditions are met. The kinetics study exhibited a high correlation coefficient close to unity (0.999) and (0.995) for the degradation of MB and CV, respectively, for the zero-order pseudo-kinetics model, which describes the model as highly suitable for the degradation of both dyes by FeNPs compared to other models. The reusability and stability of biosynthesized nano-catalysts were studied and successfully used as efficient catalysts with a slight decrease in the degradation rate more than four times. The results from this study illustrate that green synthesized FeNPs offer a cost-effective, environmentally friendly, and efficient means for the catalytic degradation of organic dyes.

Gold nanoparticles supported on alumina grafted N-doped RGO: A green catalyst for the catalytic degradation of organic dyes and deprotection of oximes

An environmentally benign synthetic protocol for the preparation of gold supported N-doped TRGO-modified γ-alumina has been reported. The research focused on the use of different strategies for reduction of GO using natural as well as chemical reducing agents. Fresh tulsi and neem leaf extract were used for bio-reduction of GO, while hydrazine hydrate and sodium borohydride were used for the chemical reduction of GO to obtain RGO. The preliminary analysis from FT-IR and BET surface area authenticated that tulsi leaf extract was the best reducing agent among others for the preparation of RGO. TRGO (tulsi leaf extract reduced graphene oxide) obtained from the reduction of GO via tulsi leaf extract was doped with nitrogen to get N-doped TRGO followed by grafting with γ-Al2O3 and immobilization of Au NPs to get the desired catalyst. The developed catalyst was later examined via different characterization techniques. Further, the synthesized catalyst shows great potential for application in degradation of various dyes and oxidative deprotection of oximes. Nitrogen doping as well as the higher specific surface area of the catalyst were two key parameters influencing the higher catalytic performance of Au@NTRGO-γ-Al2O3. The rational strategy exhibited in the present work provides new insights into the development of green, efficient and sustainable catalysts for different organic transformations.

Biosynthesis of silver nanoparticles as a reliable alternative for the catalytic degradation of organic dyes and antibacterial applications

Water bodies are being threatened continuously by various anthropogenic pollutants such as organic dyes and bacteria which led to scarcity of fresh water suitable for drinking and irrigation. Therefore, different water treatment methods have been implemented before the discharge of contaminated wastewater into water bodies. In this report, green-synthesized silver nanoparticles (AgNPs) were evaluated in the degradation of organic dyes and bacterial decontamination. The S. costus root aqueous extract was used as an environmentally benign reducing agent in the biosynthesis of AgNPs. The synthetic procedure was optimized in terms of different parameters, and several analytical techniques were used to thoroughly characterize the prepared nanocomposites including TEM, SEM, EDX, DLS, XRD, FTIR, UV/Vis, photoluminescence, and TGA. The nanoparticles were spherical, monodisperse, colloidally and thermally stable, and crystalline in nature. The efficiency of the biogenic AgNPs as catalysts for the degradation of organic dyes was evaluated against six structurally diverse dyes. These included methylene blue, phenol red, methyl orange, Congo red, orange G and safranin O. Moreover, the applicability of AgNPs as antibacterial agents was tested against K. pneumoniae, S. aureus, S. haemolyticus and E. faecalis where the zones of growth inhibition, MIC and MBC values were determined for each bacterium. Overall, the biosynthesized nanoparticles were remarkable catalysts in the discoloration of hazardous dyes and displayed notable antibacterial potency against Gram-positive and Gram-negative bacteria.

Ultra-fast magnetic catalytic degradation of organic dyes by the Fe-doped metallic 1T/1T′ MoS2 nanocomposites

This study presents a novel approach to degrading pollutants through the ultra-fast magnetic catalytic degradation of organic dyes in the dark using Fe-doped metallic 1 T/1 T′ MoS2 nanocomposites produced by the hydrothermal method. The nanocomposites demonstrated a degradation rate of 97.8% for Rhodamine B in a mere 2 min under magnetic stirring, which was 12 times and 7.65 times higher than the ZnO/MoS2 and ZnO/ZnS/(2 H) MoS2 nanocomposites respectively for Methylene Blue. This rapid magnetic catalysis could be attributed to the high magnetoelectric conversion efficiency, the MoS2 semiconductor-metal phase junction and the MoS2/FeS2 heterojunction, the strong internal electric field generated by the piezoelectric effect, and the high electrical conductivity of the metallic 1 T/1 T′ MoS2.

Biosynthesis of gold nanoparticles using aqueous extract of Ricinus cummunis leaves to augment catalytic degradation of organic dyes and study of its antifungal and antibacterial activities

In this study, biosynthesis of gold nanoparticles (Au NPs) using aqueous extract of fresh leaves of Ricinus cummunis plant is reported without the use of any synthetic chemical in the reaction process. The prepared NPs are mostly spherical in shape with some particles having triangular or hexagonal structures. The average size of the particles as calculated using TEM data is 18 nm. The biosynthesised Au NPs were studied for their application in remediation of Congo Red, Methylene Blue, Reactive Red 120 and Rhodamine B dyes present in industrial effluents. The degradation of dyes was confirmed spectrophotometrically using UV–Vis Spectrophotometer. Reactive Red 120 and Congo red dyes were most effectively reduced with 88% degradation. The Au NPs were further studied for their potential as an effective antifungal agent against fungal strains namely Candida albicans and Aspergillus fumigatus and antibacterial properties against Bacillus subtilis (Gram +ve) and Pseudomonas aeruginosa (Gram −ve) bacterial strains. The MIC values being 7.8 and 15.6 (μg/mL) for Bacillus subtilis and Pseudomonas aeruginosa respectively.

MXene-derived Ti3C2Tx/Bi4Ti3O12 heterojunction photocatalyst for enhanced degradation of tetracycline hydrochloride, rhodamine B, and methyl orange under visible-light irradiation

Visible-light responsive two-dimensional (2D) MXene heterostructure photocatalysts with synergistic photoelectron migration represent a practical approach with potential applications in water remediation. The present study reports the facile in-situ solvothermal synthesis of a heterojunction composite comprising Ti3C2Tx/Bi4Ti3O12. The novel composite photocatalyst exhibits remarkable visible-light-driven photocatalytic activity towards complete degradation of tetracycline hydrochloride (TC-HCl), rhodamine B (RhB), and methyl orange (MO) by TB-20 within 20, 50, and 60 min of illumination, respectively. Furthermore, the exposed facet Ti3C2Tx/Bi4Ti3O12 heterojunction exhibits a synergistic effect with photocatalytic reactions, as evidenced by the transfer of photogenerated carriers and generation of O2−, thereby enhancing the performance of catalytic degradation of organic dyes. This study advances the development of photocatalysis by utilizing the MXene substrate to fabricate hierarchical structure composites, enabling efficient degradation of antibiotics and solar energy conversion for future applications.

Microwave-Aided Green Synthesis of ZrO2/ZnO/AC Nanocomposite for Catalytic Degradation of Organic Dye

Microwave-Aided Green Synthesis of ZrO2/ZnO/AC Nanocomposite for Catalytic Degradation of Organic Dye

Fabrication of hierarchical flower-like WO3 nanoparticles for effective metal ions sensing and catalytic degradation of organic dyes

In this work, we report on the synthesis of flower-like tungsten oxide nanoparticles (WO3 NPs) using a simple precipitation method. This paper reports a simple method for synthesizing flower-like WO3 NPs, which can be used for environmentally treating hazardous organic pollutants. The photocatalytic degradation of model artificial Orange II and Congo red was assessed under natural sunlight irradiation. The surface morphologies, crystallinity, and binding energy of the synthesized WO3 NPs were determined. The synthesized WO3 NPs exhibited good photodegradation percentages of approximately Orange II (97.6%) and Congo red dye (98.2%) after 120 min of irradiation. Furthermore, the WO3 NPs maintained their degradation ability for up to three cycles. In addition, WO3 NPs were examined in different metal ions sensing (Hg2+, Fe2+, Cu2+, Ni2+, and Cd2+) in an aqueous solution. The results showed that the WO3 NPs exhibited excellent Cd2+ ion sensing. Based on the investigations, WO3 NPs proved to be an efficient photocatalyst and hold promise as the best material for future applications in preventing water pollution.

A simple surface modification method to prepare versatile PVDF electrospun nanofibrous felts for separation, sterilization and degradation

The discharge of oily effluents from industrial production and crude oil spills at sea result in significant water pollution, posing a major danger to the environment and human health. Due to the tiny droplet size, emulsion separation is a difficult task in the separation and purification of oily wastewater. Polydopamine (PDA) and TiO2 nanoparticles were coated on the surface of polyvinylidene fluoride (PVDF) electrospun nanofibrous to increase surface roughness, and then the low surface energy substance octadecylamine (ODA) was grafted. As a result, a superhydrophobic PVDF@PDA/TiO2@ODA nanofibrous felts with a water contact angle of 168.1° has been developed. Because of their three-dimensional porous structure, the nanofibrous felts have a porosity of up to 72.9 %. The tensile strength of a series of reinforced PVDF@PDA/TiO2@ODA nanofibrous felts reaches 30.06 MPa, which is useful for maintaining the stability of the nanofibrous felts during the pressure separation. The oil and water in the emulsion are entirely separated due to the selective permeability induced by the strong superhydrophobic and superlipophilic properties. The separation efficiency of over 99 % and flow flux of above 1100 L·m−2·h−1 are achieved. The performance of the nanofibrous felts in inhibiting bacterial growth was then investigated, and it is found that a significant inhibition circle appeared in the flat dish diffusion method, with a bacteriostasis rate exceeding 99 %. This result demonstrates that PVDF@PDA/TiO2@ODA nanofibrous felts have excellent antimicrobial properties. Finally, UV–vis absorption spectroscopy was employed to demonstrate the good catalytic degradation of organic dyes by PVDF@PDA/TiO2@ODA nanofibrous felts. PVDF@PDA/TiO2@ODA nanofibrous felts have a variety of applications in the deep separation and purification of oily wastewater due to these characteristics.

Ferrous and manganese oxalate for efficient heterogenous-Fenton degradation of organic pollutants: composite active site and mechanism perception

Abstract Composite heterogeneous catalysts of ferrous and manganese oxalate (FeC2O4/MnC2O4) were prepared via simple chemical co-precipitation. The catalytic performance was evaluated by determining the degradation efficiency of rhodamine B (RhB). Under optimum conditions, 6-1FeMn showed the best catalytic performance, and the degradation efficiency exceeded 95 % within 2 min, which was 1.4 times more than ferrous oxalate. Under a wide pH range (1–8), 6-1FeMn showed high degradation efficiency for RhB with good recyclability and reusability. By characterizing the catalysts before and after the reaction and analyzing the degradation process, a possible mechanism was proposed: Mn2+ and Fe2+ synergistically catalyzed and produced a large number of hydroxyl radicals (·OH) by forming a composite active site for efficient reactivation. Mn3+ accelerated the transfer between Fe2+ and Fe3+. In addition, C2O4 2− reactivated the active site in situ and enhanced the catalytic properties. This study provides new insight into the catalytic degradation of organic dyes using composite heterogeneous Fenton catalysts.

Application of Photocatalysis and Sonocatalysis for Treatment of Organic Dye Wastewater and the Synergistic Effect of Ultrasound and Light.

Organic dyes play vital roles in the textile industry, while the discharge of organic dye wastewater in the production and utilization of dyes has caused significant damage to the aquatic ecosystem. This review aims to summarize the mechanisms of photocatalysis, sonocatalysis, and sonophotocatalysis in the treatment of organic dye wastewater and the recent advances in catalyst development, with a focus on the synergistic effect of ultrasound and light in the catalytic degradation of organic dyes. The performance of TiO2-based catalysts for organic dye degradation in photocatalytic, sonocatalytic, and sonophotocatalytic systems is compared. With significant synergistic effect of ultrasound and light, sonophotocatalysis generally performs much better than sonocatalysis or photocatalysis alone in pollutant degradation, yet it has a much higher energy requirement. Future research directions are proposed to expand the fundamental knowledge on the sonophotocatalysis process and to enhance its practical application in degrading organic dyes in wastewater.

Nanosilver anchored alginate/poly(acrylic acid/acrylamide) double-network hydrogel composites for efficient catalytic degradation of organic dyes

Nanosilver anchored alginate/poly(acrylic acid/acrylamide) double-network hydrogel composites for efficient catalytic degradation of organic dyes

Biogenic synthesis of selenium nanoparticles using Hibiscus esculentus L. extract: Catalytic degradation of organic dye and its anticancer, antibacterial and antifungal activities

In this work, we develop the synthesis of selenium nanoparticles (B@SeNPs) using a green method using the aqueous extract of Hibiscus esculentus L. Various techniques were used to characterize bio-synthesized B@SeNPs. The mixture color was clearly changed to reddish at 45-50 °C and the extract pH = 6. According to Fourier transform infrared spectroscopy (FT-IR), the B@SeNPs were produced, capped, and stabilized using biomolecules found in plant extracts. The energy dispersive X-ray (EDX) analysis profile revealed an atomic Se signal (1.39 mV). The powder X-ray diffraction (PXRD) pattern confirmed the hexagonal phase crystalline form of B@SeNPs. The zeta potential for SeNPs was determined to be -51.3 mV. Scanning electron microscope (SEM) and transmission electron microscopy (TEM) micrographs revealed spherical Se particles with sizes of roughly 62 nm. Furthermore, B@SeNPs can degrade methylene blue dye by 98.3% at 21 min with a rate constant of 0.1023 min-1 in the presence of NaBH4. In biological evaluation, the synthesized nanoparticles have been proven to be effective against two human cancers (AGS and MCF-7 cells) with IC50 values of 20.46 and 88.43 µg/mL, respectively. Additionally, B@SeNPs showed high safety in the Beas cell line (normal) at 123 µg/mL as the highest concentration. The biofabricated SeNPs had a moderate antibacterial effect against ATCC and multidrug-resistant clinical isolates. They had no antifungal activity against the tested fungus strains except C. albicans (IFRC 1873), with a MIC value of 138.75 µg/mL. Finally, the green-synthesized B@SeNPs could be a contender for further testing as a chemotherapeutic agent in the treatment of some human cancers.

One-pot green synthesis of silver nanoparticles using brittle star Ophiocoma scolopendrina: Assessing biological potentialities of antibacterial, antioxidant, anti-diabetic and catalytic degradation of organic dyes

In the current study, aqueous extract of O. scolopendrina (OSE) was used to synthesize AgNPs in a simple and environmentally friendly manner. The biosynthesized OSE-AgNPs were also assessed for its catalytic, antibacterial, anti-diabetic, antioxidant and dye degradation properties. The techniques like UV–visible spectroscopic examinations, TEM, SEM, TGA, zeta potential and FT-IR were used in the characterization investigations. The bioproduction of OSE-AgNPs was preliminary confirmed by UV–visible spectroscopic based investigation followed by microscopic visualization. The synthesized OSE-AgNPs exhibited a reddish brown colour and nearly spherical forms with sizes between 5 and 50 nm quantified by TEM and SEM. The attendance of functional groups like –OH and –NH present in OSE caps on the AgNPs surface was confirmed by FTIR analysis. Interestingly, in the presence of OSE-AgNPs, the degradation of dyes (CV, 95% and EY, 96% in 15 min) were noticeably accelerated. Further, OSE-AgNPs demonstrated substantial antibacterial activity; robust antioxidant properties andnotable anti-diabetic activities. This is the first account on the biosynthetic process of AgNPs using the aqueous extract of O. scolopendrina.

Photo-Fenton catalytic anti-fouling membranes for efficient elimination of radionuclides and organic contaminants

The complexity of nuclear industry effluents necessitates novel treatment capable of facilitating water recycling and byproduct recovery. Many membrane-based technologies have become increasingly important for sewage water disposal because of their simple operation and scale-up for industrial applications. However, the membrane biofouling due to microbial attachment has become a serious issue, resulting in decreased removal efficiency for radionuclides and organic pollutants. Herein, by immobilizing the hybrid tannic acid (TA)/zero-valent iron (ZVI) nanostructures (TZ) onto the blow-spun amidoximed polyacrylonitrile (AOP)/zeolitic imidazolate framework-90 (ZIF-90) composite nanofibers, the ultimate AOP/ZIF-90@TA/ZVI (AZ@TZ) membranes with covalently cross-linked coatings were fabricated for synergistic adsorption-chemical reduction of uranium, photo-Fenton catalytic degradation of organic dyes, and ZVI/Zn2+-mediated resistance against bacterial cells. In order to assess the membrane's efficacy in eliminating uranium ions, a series of studies involving adsorption behavior were performed. The antibacterial and antifouling tests were further carried out using typical bacteria and organic dyes. The AZ@TZ hybrid membranes exhibited high uptake kinetics and the elimination capacity of uranium (140.06 mg/g) at pH 5.0, as well as excellent properties for photodegradation of organic dyes and inactivation of the bacteria within the biofilms. The novel integrated photo-Fenton and membrane-based technique offers fresh ideas for extremely effective radioactive sewage disposal.

Fabrication of tannin-based hydroxyl-rich, uniform and size-controllable nanospheres as carriers for silver nanoparticles

High loading of Ag nanoparticles (Ag NPs) with small sizes on catalyst carriers/support is crucial to achieve efficient catalysis, such as catalytic degradation of organic dyes in wastewater; however, it is still challenging to develop Ag NPs catalyst carriers/support with excellent Ag NPs loading. In this work, we developed bio-based (tannin and lignin-derived catechol) nanospheres (TCR) that are hydroxyl-rich, highly uniform, size-controllable, and the resultant TCR nanospheres were subsequently used as catalyst carriers/support for Ag NPs (TCR@Ag), achieving a high loading of Ag NPs yet with the ultrafine nanoparticles. The size of as-prepared TCR nanospheres can be adjusted from 737 nm to 403 nm by regulating the amount of tannin added, and the polydispersity index (PDI) of TCR nanospheres is as low as 0.042, indicating remarkable nanosphere uniformity. As catalyst carriers of Ag NPs, the use of tannin makes TCR nanospheres rich in phenolic-OH groups, which is responsible for the well-dispersed and high-density loading of Ag NPs, and the highest loading is 48.4 wt%; meanwhile, the size of Ag NPs is only 16.8 nm. The as-prepared TCR@Ag catalysts show superior catalytic performance for the typical organic dye-containing wastewater samples, and the reaction rate constants are 2.44 min−1 and 4.87 min−1 for methylene blue (MB) and methyl orange (MO), respectively, outperforming those of the most reported Ag-based catalysts. In addition, TCR@Ag catalysts also possess good environmental adaptability, dispersion stability, reusability, antioxidation activity, and negligible biological toxicity, so the novel TCR@Ag catalysts have great potential as effective catalysts for environmental remedy purpose.

Synthesis of PVP-capped trimetallic nanoparticles and their efficient catalytic degradation of organic dyes.

The study proposes a simple and efficient way to synthesize a heterogeneous catalyst that can be used for the degradation of organic dyes. A simple and fast chemical process was employed to synthesize Au: Ni: Co tri-metal nanohybrid structures, which were used as a catalyst to eliminate toxic organic dye contamination from wastewater in textile industries. The catalyst's performance was tested by degrading individual dyes as well as mixtures of dyes such as methylene blue (MB), methyl orange (MO), methyl red (MR), and Rose Bengal (RB) at various time intervals. The experimental results show the catalytic high degradation efficiency of different dyes achieving 72-90% rates in 29 s. Moreover, the material displayed excellent recycling stability, maintaining its degradation efficiency over four consecutive runs without any degradation in performance. Overall, the findings of the study suggest that these materials possess efficient catalytic properties, opening avenues toward their use in clean energy alternatives, environmental remediation, and other biological applications.

Ferrimagnetic (α-Mn3O4/MnO)@rGO nanocomposite as potential adsorbent for organic pollutant dye

Room temperature ferrimagnetic nanocomposite (α-Mn3O4/MnO)@rGO with significant magnetic properties was developed by sol–gel method followed by calcination at higher temperature. X-ray diffraction studies established the formation of phase and HR-TEM images asserted its morphology. The elemental mapping using a HAADF-STEM confirmed the presence of C, O and Mn which was further validated from their interfacial bonding characteristics by FTIR and XPS studies. The UV–visible DRS, Mott-Schottky and impedance results suggested its ability to degrade organic dyes by interacting with reactive oxygen species (ROS) formed via Fenton-type reaction between catalyst and H2O2 or absorbing photon or involving both photo-Fenton type reaction. The catalytic degradation of organic dye, methylene blue (MB) was found to be about 91 % in 15 min and it reached to 97.6 % in next 45 min via H2O2 mediated Fenton-type reaction at ambient temperature, which outperforms the other Mn-O based catalysts. The observed higher catalytic activity could be attributed to the synergistic effects of rGO and α-Mn3O4/MnO nanoparticles. Further, catalytic degradation efficiency of MB was found to be dependent on pH of the medium, concentration of dye and amount of catalyst. Moreover, this nanocatalyst can be reused for degradation of organic dyes due to its inherent magnetic properties.