Variable Oxidation States Research Articles

First-principles study on electronic, mechanical, and optical properties of pressure-induced vanadium-based perovskite KVO3

Vanadium-based compounds exhibit a variety of excellent characteristics due to their variable oxidation states. In this study, Density Functional Theory (DFT) is performed to investigate the structural, electronic, mechanical, and optical properties of KVO3 under high pressure. The thermodynamical and mechanical stabilities under high pressure are probed by the negative value of formation enthalpy and Born-mechanical stability criteria, respectively. KVO3 displays a nearly metallic nature in both pressurized and unpressurized systems owing to its remarkably narrow band gap. Furthermore, a positive pressure coefficient of the band gap is revealed from electronic properties. A lower effective mass value for charge carriers indicates KVO3's suitability for optoelectronic applications. The mechanical properties indicate that increasing pressure results in a slight increase in elastic constants, elastic moduli, hardness, and machinability index. Additionally, it has been disclosed that it is capable of enduring localized plastic deformation and fracturing under intense pressure in a prospective application. The calculations of the complex dielectric function, absorption, reflectivity, conductivity, refractive index, and loss function for KVO3 with and without pressure reveal a substantial behavior change. The absorption edge exhibits a significant blue shift with the applied pressure. The high peaks in the UV region suggest that it can be used in UV detectors and anti-reflection coatings. The refractive index shows promising application in waveguides.

Compositional and optical characteristics of aqueous brown carbon and HULIS in the eastern Indo-Gangetic Plain using a coupled EEM PARAFAC, FT-IR and 1H NMR approach

This study provides insights into the fluorophoric composition of aqueous brown carbon (BrCaq) and chemically-separated humic-like substances (HULIS): neutral HULIS (HULIS-n; at pH = 7) and acidic HULIS (HULIS-a; at pH = 2) on a seasonal and day-night basis in the eastern Indo-Gangetic Plain (IGP), India. A coupled approach including excitation-emission matrix (EEM) fluorescence and parallel factor analysis (PARAFAC) model, Fourier-transformed infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance (1H NMR) spectroscopy was employed to understand the links between structural, compositional and fluorophoric characteristics of BrCaq and HULIS fractions. HULIS fluorophores (HULISfluoro) with varying oxidation states transported from the northwest IGP were dominant during biomass burning seasons (post-monsoon and winter), while protein-like fluorophores (PRLISfluoro) from marine emissions showed large contributions during summer. HULIS-n moieties were mostly primary in nature with higher conjugation, while HULIS-a were associated with secondarily formed and aged species with a larger contribution from degradation products. A substantial presence of tyrosine-like proteins in both chemically-separated HULIS fractions indicated that atmospheric HULIS is not entirely humic or fulvic-like in the eastern IGP. Finally, the dominance of H-C-O groups across seasons suggested consistent fossil fuel signatures along with season-specific influence of photodegradable cellulose from marine organisms in the summer and biomass burning in the post-monsoon and winter.

V2O5 coral microspheres: High performance electrode material for Li-ion supercapacitor

Energy storage devices forms lifeline for most modern devices. The short life cycle and lower power density of batteries has prompted development of supercapacitors as potential alternatives. Li-ion supercapacitors, is an emerging class of energy storage devices. Natural abundance and availability of variable oxidation states make V2O5 an attractive electrode material. Here, we report synthesis of coral microspheres of V2O5 using low temperature solvothermal technique, as electrode material for Li-ion supercapacitor. The annealing temperature plays a cucial role in formation of microspherical aggregates, dictates their surface area and hence the energy storage performance. Samples annealed at 400 °C showed specific capacitance of ∼360 F/g at current density of 0.5 A/g. Our studies suggest that V2O5 based nanostructures holds significant potential for development of hybrid Li-ion supercapacitors.

Stabilization of Ni-containing Keggin-type polyoxometalates with variable oxidation states as novel catalysts for electrochemical water oxidation.

The development of new recyclable and inexpensive electrochemically active species for water oxidation catalysis is the most crucial step for future utilization of renewables. Particularly, transition metal complexes containing internal multiple, cooperative metal centers to couple with redox catalysts in the inorganic Keggin-type polyoxometalate (POM) framework at high potential or under extreme pH conditions would be promising candidates. However, most reported Ni-containing POMs have been highly unstable towards hydrolytic decomposition, which precludes them from application as water oxidation catalysts (WOCs). Here, we have prepared new tri-Ni-containing POMs with variable oxidation states by charge tailored synthetic strategies for the first time and developed them as recyclable POMs for water oxidation catalysts. In addition, by implanting corresponding POM anions into the positively charged MIL-101(Cr) metal-organic framework (MOF), the entrapped Ni2+/Ni3+ species can show complete recyclability for water oxidation catalysis without encountering uncontrolled hydrolysis of the POM framework. As a result, a low onset potential of approximately 1.46 V vs. NHE for water oxidation with stable WOC performance is recorded. Based on this study, rational design and stabilization of other POM-electrocatalysts containing different multiple transition metal centres could be made possible.

Exploring the impact of various reducing agents on Cu nanocluster synthesis.

The synthesis of copper (Cu) nanoclusters (NCs) has experienced significant advancements in recent years. Despite the exploration of metal NCs dating back almost two decades, challenges specific to Cu NC synthesis arise from the variable oxidation states and heightened reactivity of intermediate Cu complexes, distinguishing it from its analogous counterparts. In this study, we present a comprehensive overview of this newly evolving research domain, focusing on the synthetic aspects. We delve into various factors influencing the synthesis of Cu NCs, with specific emphasis on the role of reducing agents. The impact of the reducing agent is particularly pivotal in this synthetic process, ultimately influencing the formation of model M(0)-containing NCs, which are less readily accessible in the context of Cu NCs. We anticipate that this frontier article will pave the way for accelerated research in the field of Cu NCs. By aiding in the selection of specific reaction conditions and reducing agents, we believe that this work will contribute to a faster-paced exploration of Cu NCs, further advancing our understanding and applications in this exciting area of nanomaterial research.

A Review on Microwave Assisted Synthesis of Transition Metal Oxides and their Potent Application as Supercapacitors

AbstractPreparation of transition metal oxides and mixed metal oxides via a microwave‐assisted method that permits processes to be completed in a quicker reaction time with the formation of homogenous and well‐dispersed nanoparticles. Recently, due to the environmentally friendly nature of this technique, it has become an important approach to green chemistry. The major advantage of microwave‐assisted synthesis includes clean, fast, efficient, less time‐consuming, highly accelerated rate, high yield, and an economic method. In this review, we have discussed the process of microwave synthesis and also compared this with other synthetic methods. A discussion of transition metal oxides in groups was performed where we have discussed their synthetic route and reaction conditions along with the effect on morphology and other properties. Additionally, the application of transition metal oxides as supercapacitors was also discussed. Since then, researchers have gained a lot of interest in transition metal oxides as energy storage devices due to their low‐cost, energy efficient, long cycle life, and improved electrical, thermal, and chemical stability, variable oxidation states and excellent redox properties. However, they cannot meet the need for high‐performance energy devices due to their low conductivity.

Synergistic chemical and structural colorations in early polychromic ceramics -A case study of Tang Changsha glaze

The emergence of polychromic glazes during Tang period reflects intercultural communications than 1000 years ago. It also highlights a significant technological advance in ceramic history. However, the colouration mechanisms in high-fired Tang glazes are still not well understood. In this work, we unravel the mysteries of colourful Tang glazes through a case study of the Changsha kiln samples. Colorants in varied concentrations and oxidation states as well as microstructures resulted from phase separation and impurity are found responsible for the glaze appearances. More importantly, we highlight the mixing effects of different coloration ingredients that generate additional colours and hues. A direct observation of co-existence of reduced copper nanoparticles and liquid-liquid phase separation in Tang Changsha glaze is achieved as well. These fresh results and analyses provide an insightful assessment of the diversity of Tang Changsha glazes and promote the perception of ancient ceramics in a more scientific manner.

Design and synthesis of hierarchical MnO–Fe3O4@C/expanded graphite composite for sensitive electrochemical detection of bisphenol A

Hierarchically nanostructured binary transition metal oxide-based materials with high conductivity and catalytic activity are quite attractive for the electrochemical quantitative detection of environmental pollutants due to their natural abundance, variable oxidation state, and excellent synergies between metal sites. Herein, a new hierarchical MnO–Fe3O4@C/expanded graphite (EG) composite is designed and synthesized through a simple and in situ annealing method with the utilization of bimetallic organic framework (FeMn-MOF)/EG precursor. The synthesized MnO–Fe3O4@C/EG composite possesses a unique hierarchical nanoarchitecture that small-sized bimetallic oxide nanoparticles of 10–40 nm completely encapsulated by amorphous carbon layers of 2–4 nm are uniformly distributed on the EG platform. This distinctive structure combines the advantages of high conductivity, excellent catalytic activity, and strong stability. Resultantly, when it is applied to monitor environmental endocrine disruptors, the sensor exhibits a significant catalytic effect on the electrochemical oxidation of bisphenol A (BPA), inducing an amplified response current. In addition, the sensor shows a wide linear range of 1–50 μM and 50–400 μM for the BPA monitor, giving a sensitivity of 5208.8 and 1641.9 μA mM−1 cm−2, respectively. This study offers a new approach to design hierarchical binary metal oxide-based sensing materials as well as to explore their electrochemical properties and applications for the determination of emerging contaminants.

Potentially toxic elements speciation in bottom ashes from a municipal solid waste incinerator: A combined SEM-EDS, µ-XRF and µ-XANES study

Bottom Ashes from Municipal Solid Waste Incinerators and Waste to Energy plants represent an interesting source of secondary raw materials for many applications, like urban mining and inclusion in concrete, and road pavement. However, Bottom Ashes may contain potentially toxic elements, whose actual toxicity depends essentially on their oxidation state and mineralogical environment. For this reason, a representative sample of bottom ashes from Parma Waste to Energy plant has been selected to investigate the chemical speciation of Cr, Ni, Pb, Co, Zn and Cu by means of complementary techniques: Scanning Electron Microscopy with Energy Dispersive X-Ray Spectroscopy (SEM-EDS), micro X-Ray Fluorescence (µ-XRF) mapping and X-Ray Absorption Near Edge Structure (XANES) measurements by synchrotron radiation. This multi-technique approach allowed to obtain a general image of the mineralogical and chemical environment in which these elements are found. SEM-EDS analyses show the presence of Zn and Pb both in minerals and in glass matrix. Cr has been detected in the form of oxide and in spinel structure (chromite) whereas Co and Cu are found as alloy or metal inclusions. µ-XRF mapping reveals that Cu, Ni and Cr are generally associated to Na, K and Si suggesting their presence in glass matrix. XANES investigations exhibit that Cu has a variable oxidation state that suggesting its presence in the form of oxide, hydroxide, acetate and metal. Zn is mainly found as +II and in a number of different phases (including Zn-carbonates, in agreement with SEM-EDS data). Cr has been found only as +III, with XANES features resembling those of chromite, whereas as +VI was never identified. Ni and Co were found either as metal form and oxides. Pb spectra show a good match with oxides.

Electrochemical behavior of V/Ce co-doped carbon shell-coated NiO nanocomposite for alkaline OER and supercapacitor applications

Developing highly efficient, versatile, durable, and non-precious electrode materials for sustainable electrochemical energy storage and conversion technologies is still a long-term challenge in the energy sector for researchers. Herein, we developed a sustainable and bifunctional electrode, based on V/Ce co-doped NiO coated with carbon grown on Ni foam substrate through a simple and cost-effective sol-gel method. OER activity and supercapacitance characteristics have been validated by coupling contact and morphological porous features (unique core-shell) and also demonstrated satisfying electronic structural attributes for grown material. The formation of defective lattice and oxygen vacancies in NiO by co-doping along with varying oxidation states of V, Ce, and Ni was confirmed by XPS. The modified material as a supercapacitor electrode, manifested superior specific capacitance of 1719 F g−1 at 2 A g−1 current density and outstanding cycling stability performance with 98.21 % retention after 5000th cycles. This highly efficient cycling is due to abundant redox states and surface redox functionalities of carbon, providing an easy pathway to transfer ions. The redox behavior of the composite catalyst also contributes toward high conductivity and the electrochemically active surface area thus showed a small Tafel slope of 35.4 mV dec−1. The current density of 10 mA cm−2 showed a low overpotential of 238 mV. In a practical system, it also revealed significant stability for OER over 100 h of continuous electrolysis, tested by chronoamperometry. The influence of co-doping and carbon support highlights the remarkable advantages of electrochemical performance and enriches its application prospect for efficient electrolysis and storage technology.

Synthesis and Evaluation of Pristine Co and Hybrid Ni-Co Metal-Organic Frameworks (MOFs) as Potential Electrodes for Electrochemical Energy Storage Applications

Hybrid metal-organic frameworks (MOFs) have many positive features like high porosity, surface area, and conductivity as compared to other materials. They have better potential than pristine ones due to the reason that hybrid materials have good faradic responses due to variable metal oxidation states. These all-favorable factors make hybrid MOFs more potential electrodes for energy storage. In this study, hybrid Ni-Co MOFs presented good specific capacitance of 745 F g-1 (447 C g-1 @ 1 A g-1) in comparison with pristine Co MOFs of 109 F g-1 (65.5 C g-1 @ 1 A g-1). Also, the hybrid MOFs showed superior electrical conductivity of 1353.3 S cm-1 as compared to pristine MOFs. The charge transfer resistance (Rct) of hybrid MOFs was 2.271 Ω pretty much greater than pristine MOF and other closely related studies. The best electrochemical performance was attributed to the synergic effect of Ni, Co, and organic ligand.

Fluorescence Quenching Study Of 5-Sulphosalicylic Acid Doped Polyaniline-Γ-Fe2o3 Composite For High Energy Material Sensing (Fe-Spani)

Background: Polymeric nanocomposites containing metal oxides are of interest to researchers because these materials show hybrid properties that are generated from both components. Due to the control and design of structural properties at the nanoscale scale, they have specialized properties for a range of applications. Researchers have tried to improve the desirable characteristics and thus increase their application by reinforcing them with nanoscale materials to provide them with better properties than conventional micro composites. Objective: In our present work we have used 5-sulphosalicylic acid doped polyaniline-γ-Fe2O3 composite (Fe-SPAni) to detect explosives using fluorescence quenching method. Along with ease of synthesis and low cost, Fe-SPAni possesses a variable oxidation state which is important for trace detection of the analytes. Methods: We used the fluorophore Fe-SPAni to detect High Energy Materials (HEMs) using the fluorescence quenching approach, which is still difficult to achieve. UV-Vis spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM/EDAX) were used to determine the molecular structure of the Fe-SPAni composite produced by oxidative chemical polymerization; CV studies were performed to investigate the electrochemical properties. HEMs such as dinitrobenzene (DNB), pentaerythritol tetranitrate (PETN), trinitrotoulene (TNT), 1,3,5-trinitroperhydro-1,3,5-triazine (RDX), and hexanitrohexaazaisowurtzitane(CL-20) were used as quenchers.The fluorescence quenching process was determined using the Stern-Volmer graph. Results: The Stern-Volmer(S-V) plot and limit of detection (LOD) data showed that PETN had the greatest results for the quenching constant value (Ksv) (Ksv =1.33 x 106 M-1 and 1.4x 10-6M, respectively). Conclusion: The research points to Fe-SPAni as a promising contender for sensing explosives.

Electronic Structure of the Complete Series of Gas-Phase Manganese Acetylacetonates by X-ray Absorption Spectroscopy.

Metal centers in transition metal-ligand complexes occur in a variety of oxidation states causing their redox activity and therefore making them relevant for applications in physics and chemistry. The electronic state of these complexes can be studied by X-ray absorption spectroscopy, which is, however, due to the complex spectral signature not always straightforward. Here, we study the electronic structure of gas-phase cationic manganese acetylacetonate complexes Mn(acac)1-3+ using X-ray absorption spectroscopy at the metal center and ligand constituents. The spectra are well reproduced by multiconfigurational wave function theory, time-dependent density functional theory as well as parameterized crystal field and charge transfer multiplet simulations. This enables us to get detailed insights into the electronic structure of ground-state Mn(acac)1-3+ and extract empirical parameters such as crystal field strength and exchange coupling from X-ray excitation at both the metal and ligand sites. By comparison to X-ray absorption spectra of neutral, solvated Mn(acac)2,3 complexes, we also show that the effect of coordination on the L3 excitation energy, routinely used to identify oxidation states, can contribute about 40-50% to the observed shift, which for the current study is 1.9 eV per oxidation state.

Facile hydrothermal synthesis of MoS2 nano-worms-based aggregate as electrode material for high energy density asymmetric supercapacitor

Nowadays, supercapacitors and batteries are trending electrochemical energy storage devices. However, their low energy density and uncertain power density limited their applications, respectively. Recently, the latest innovation in energy storage devices, called hybrid supercapacitors, has appeared as an eventual energy storage device that demonstrates a hybrid storage mechanism of both supercapacitors and batteries. In this work, MoS2 has been prepared by the facile hydrothermal method, characterized by different techniques, and applied as an electrode in supercapacitors and supercapatteries. The XRD patterns and EDX confirm the successful synthesis of MoS2 with an average crystallite size of 62.25 nm, while the SEM images show the randomly oriented nanoworms of MoS2. The XPS spectrum depicts the presence of variable oxidation states of molybdenum (Mo4+and Mo6+) in the MoS2. The electrochemical performance shows that the highest specific capacitance and specific capacity reached 1866.66 F/g and 1119.99 C/g, respectively, at a scan rate of 5 mV/s for MoS2. The asymmetric supercapacitor device is made from (Graphite/MoS2) using as a working electrode and activated carbon as a cathode, which are separated by filter paper. Furthermore, the Dunn's model is utilized to evaluate of capacitive and battery mechanisms and shows the dominant role of diffusive and surface-controlled developments at low and high scan rates, respectively, owing to the change in diffusion time of electrolyte species. The fabricated device shows an energy density and power density of 103.51 Wh/kg and 3807.59 W/kg at a current density of 1 and 7 A/g, respectively, with 93.52% capacity stability and 99.8% coulombic efficiency. This excellent performance of MoS2 is believed to be a potential electrode candidate for asymmetric supercapacitor applications.

Mn Incorporated CeO2 Lattice Endorsement of Electrochemical Performance in Symmetric Supercapacitor Device

The greater charge transfer rate and variable oxidation states make cerium oxides a potential candidate to be used for energy storage application. Also, doping heteroatom in the architecture of well‐structured cerium oxide can significantly improve capacitive performance. Herein, manganese doped cerium oxide‐based nanostructured thin film is synthesized via the pulse laser deposition method for the accomplishment of the supercapacitive performance of the electrode. Due to the incorporation of Mn into the lattice of CeO2 electrode, the specific capacitance has been increased from 292 to 395 F g−1 at 2 mA cm−2 and capacitance retention also increased to 92.5% in 0.5 m Li2SO4 electrolyte solution. Later, an Mn–CeO2//Mn–CeO2@SS device is fabricated, which exhibit a specific capacitance of 85 F g−1 at 2 mA cm−2 within the working voltage window of +1.2 V. The symmetric supercapacitor (SS) device with high energy and power densities of 31 Wh kg−1 and 1673 W kg−1, respectively, also exhibits excellent cyclic retention of 87.6% even after 10 000 cycles. The Mn‐doped CeO2 symmetric supercapacitor device's electrochemical richness makes it an appropriate material for supercapacitor applications.

Boosting zinc-ion storage in vanadium oxide via“dual-engineering” strategy

Vanadium oxide, with large interlayer spacing and variable oxidation state, has been widely favored by researchers as a promising cathode material for aqueous zinc ion batteries (ZIBs), but its non-ignorable disadvantages such as slow zinc ion diffusion kinetics, fragile structure, and poor electrical conductivity limit the practical application. Herein, it is found via density functional theory (DFT) calculation that the simultaneous introduction of oxygen vacancies and crystalline water can not only improve the conductivity of the vanadium oxide but also significantly reduce the diffusion energy barrier in the process of Zn2+ (de)intercalation. Hence, we employed a feasible over-reduction solvothermal method to introduce more oxygen vacancies and crystalline water into Od-V2O5·4VO2·0.82 H2O (denoted as VHO). Based on the synergistic benefits of this dual engineering strategy, the VHO cathode exhibits impressive performance metrics (194.5 mAh g−1 at 20.0 A g−1). Further, systematic ex-situ characterizations reveal a mechanism for the sequential dominance of Zn2+/H+ (de)intercalation in the VHO cathode, i.e., insertion of Zn2+ dominates high voltages (1.40 −0.70 V) and H+ dominates low voltages (0.70 −0.20 V). The convenient dual-modification strategy is a hopeful one to put forward the application of ZIBs.

NiMoO4/Eu6MoO12 composite on foam Ni as electrode material for supercapacitors

By a one-step hydrothermal reaction, NiMoO4/Eu6MoO12 composite supported on nickel foam was successfully synthesized. The properties of the composite were optimized by adjusting the content of europium nitrate in the reactants. The NiMoO4 nanorods array formed on nickel foam was used as structural support, and Eu6MoO12 nanoparticles were added to the surface, increasing the material's specific surface area and the active site.The two chemicals' combined effect made the electrode reaction more reversible. In addition, Eu with variable oxidation states increased the oxygen vacancy and promoted the Faraday reaction. And the formation of Eu6MoO12 also significantly reduced the charge transfer resistance of the composite, it influenced the electrochemical behavior of materials. Electrochemical experiments show that the specific capacity of NiMoO4/Eu6MoO12 is 1184.0 C g−1 at 1 A/g. The energy density of NiMoO4/Eu6MoO12//AC device is 22.34 W h kg−1 when the power density is 749.52 W kg−1. In addition, the device also has a capacity retention rate of 80.2% after 5000 cycles. The material's superior electrochemical performance demonstrates that it has promising future applications in the realm of energy storage.

Effect of Sr-doping on electronic and thermal properties of Pr2-xSrxFeCrO6 (0≤x≤1) oxide materials synthesized by using sol-gel technique

ABSTRACT The thermoelectric properties of a new type of Pr2-xSrxFeCrO6 double perovskite were investigated at higher temperature after its sol-gel synthesis. The XRD results validate the single-phase orthorhombic structure, and the crystallite sizes meet the morphological measurements. XPS examination, which formed the defect sites in these oxides, confirmed the varied oxidation states of constituents. The temperature-dependent electrical conductivity (σ) was poor in the original Pr2FeCrO6 composition, but after substituting Sr on the Pr-site, a significant rise in σ with two semiconductors and one metal transition was observed. A positive Seebeck coefficient confirmed the presence of a p-type charge carrier in the entire composition, and the charge transport mechanism was driven by the SPH model. Thermal conductivity increases in all doped samples, while it decreases in pristine compounds over the broad analyzed temperature range. Thermal expansion coefficient increased after doping in oxygen-deficient compound. The PrSrFeCrO6 compound had the maximum ZT (0.105), which was 3.9 times higher than that of the pristine compound.

Protein-Assisted Molybdenum Disulfide as Biomimetic Nanozyme for Antibacterial Application.

Molybdenum-based nanomaterials with variable oxidation states can be developed as nanozyme catalysts. In this work, we developed a one-pot method for the preparation of molybdenum disulfide assisted by protein. Protamine was used as a cationic template to link molybdate anions and form complexes. During hydrothermal synthesis, protamine can affect the nucleation process of molybdenum disulfide and inhibit their aggregation, which facilitates the fabrication of small-sized molybdenum disulfide nanoparticles. Moreover, the abundant amino/guanidyl groups of protamine could both physically adsorb and chemically bond to molybdenum disulfide and further modulate the crystal structures. The optimized size and crystalline structure enabled a higher exposure of active sites, which enhanced the peroxidase-like activity of molybdenum disulfide/protamine nanocomposites. Meanwhile, the antibacterial activity of protamine was retained in the molybdenum disulfide/protamine nanocomposites, which could synergize with the peroxidase-like activity of molybdenum disulfide to kill bacteria. Therefore, the molybdenum disulfide/protamine nanocomposites are good candidates for antibacterial agents with lower chances of antimicrobial resistance. This study establishes an easy way to design artificial nanozymes by compounding suitable components.

Peroxymonosulfate activation with an α-MnO2/Mn2O3/Mn3O4 hybrid system: parametric optimization and oxidative degradation of organic dye.

The present study proposed the synthesis of low-toxicity and eco-friendly spherically shaped manganese oxides (α-MnO2, Mn2O3, and Mn3O4) by using the chemical precipitation method. The unique variable oxidation states and different structural diversity of manganese-based materials have a strong effect on fast electron transfer reactions. XRD, SEM, and BET analyses were used to confirm the structure morphology, higher surface area, and excellent porosity. The catalytic activity of as-prepared manganese oxides (MnOx) was investigated for the rhodamine B (RhB) organic pollutant with peroxymonosulfate (PMS) activation under the condition of control pH. In acidic conditions (pH = 3), complete RhB degradation and 90% total organic carbon (TOC) reduction were attained in 60 min. The effects of operating parameters such as solution pH, PMS loading, catalyst dosage, and dye concentration on RhB removal reduction were also tested. The different oxidation states of MnOx promote the oxidative-reductive reaction under acidic conditions and enhance the SO4•-/•OH radical formation during the treatment, whereas the higher surface area offers sufficient absorption sites for interaction of the catalyst with pollutants. A scavenger experiment was used to investigate the generation of more reactive species that participate in dye degradation. The effect of inorganic anions on divalent metal ions that genuinely occur in water bodies was also studied. Additionally, separation and mass analysis were used to investigate the RhB dye degradation mechanism at optimum conditions based on the intermediate's identification. Repeatability tests confirmed that MnOx showed superb catalytic performance on its removal trend.