Reaction Of MnO2 Research Articles

Mesoporous manganese dioxide prepared by nano-casting: An efficient catalyst for of methyl orange and oxalic acid degradation in aqueous solution

In the present study, mesoporous manganese dioxide catalysts with large high specific surface area, pore volume and large pore size structure were synthesised using the nano-casting method with a mesoporous structure of silica SBA-15 as a hard template. Therefore, the physical and chemical properties of mesoporous MnO2 were characterised by XRD, FT-IR, Raman, UV–Vis, N2 adsorption-desorption, SEM, EDS, TEM, TG and XPS. In this study, the oxidative reactivity of MnO2 corresponding to methyl orange (MO) and oxalic acid (OA) was assessed. MnO2 was found to contain the most abundant oxygen vacancies and easily reducible surface adsorbed oxygen (Olatt), which facilitates the catalytic utilisation of ozone. As a result, the highest catalytic performance was achieved for methyl orange and oxalic acid, with degradation efficiencies of 98.37% and 92.96%. This present study deepens our understanding of manganese dioxide catalyzed ozone and provides a reference for improving process efficiency.

Facile microwave-assisted synthesis of magnetic ferrite: Rapid interfacial reaction underlying intensifying mechanism

Microwave-assisted (MW-assisted) heating is clean and intensively used to synthesize materials owing to the high-efficiency volumetric and selective heating modes. In the current paper, a design and facile synthesis of magnetic ferrite ceramics by microwave-assisted heating of MnO2 and Fe2O3 was conducted to reduce the synthetic temperature of conventional heating. The microwave absorptivity and temperature rise characteristics of the MnO2–Fe2O3 system were first assessed for the material design of MnFe2O4, and then the phase transformation, microstructure evolution, and magnetism change of the MnO2–Fe2O3 system heated under conventional and MW-assisted heating were compared. Investigations on electromagnetic properties and heating behaviors of MnO2–Fe2O3 mixture suggested that a suitable cylinder sample size for microwave heating was designed to be 10 mm in diameter and 10 mm in length based on the dielectric loss and magnetic hysteresis loss of microwave penetration at different depths. The intensifying mechanism for microwave heating was associated with the rapid interfacial reaction between MnO2 and Fe2O3. Under microwave irradiation at 935 °C, some perfectly crystallized MnFe2O4 was preferentially formed at the interface of MnO2 and Fe2O3, and these MnFe2O4 were evenly distributed in the cylinder samples. Similar to the “self-propagating” effect, the in-situ generation of MnFe2O4 with good energy conversion ability evenly distributed everywhere of the cylinder would facilitate the reaction of MnO2 and Fe2O3 under microwave irradiation based on the distinctive selective and volumetric heating. Compared with conventional heating at 1200–1250 °C, ferrite synthetic temperatures via MW-assisted heating decreased to 900–1000 °C, and the low-temperature synthesis of ferrite also had a good electromagnetic performance. Eventually, the clean and value-added utilization of low-grade ferruginous manganese ores via MW-assisted heating was validated for the preparation of manganese ferrite from minerals under reduced roasting temperatures.

In-Situ Regulated Competitive Proton Intercalation and Deposition/Dissolution Reaction of Mno2 for High-Performance Flexible Zinc-Manganese Battery

In-Situ Regulated Competitive Proton Intercalation and Deposition/Dissolution Reaction of Mno2 for High-Performance Flexible Zinc-Manganese Battery

Tumor microenvironment triggered local oxygen generation and photosensitizer release from manganese dioxide mineralized albumin-ICG nanocomplex to amplify photodynamic immunotherapy efficacy

Photodynamic therapy (PDT) has emerged as a potential clinical strategy for tumor therapy. It can generate reactive oxygen species (ROS) to cause the chemical damage of tumor cells and promote the immune killing effects of T cells on tumor cells in the presence of enough oxygen and PDT drugs. However, most solid tumors are in a state of oxygen deficiency, which seriously limit the efficacy of PDT in generation enough ROS. Besides, few safe PDT drugs with ideal pharmacokinetic behavior are available in the clinic, which severely limits the clinical transformation and application of PDT. Herein, we utilized manganese chloride to mineralize the hydrophilic indocyanine green/albumin polyplexes (ICG@BSA@MnO2) by using bio-mineralized method to solve these problems of PDT. These ICG@BSA@MnO2 nanoparticles could circulate in the blood for a long period other than quickly removed from body after 30 min like free ICG. When accumulated at the tumor site, ICG was responsively released in the presence of hydrogen peroxide. Apart this, the tumor hypoxia microenvironment was also reversed owing to enhanced O2 generation by the reaction of MnO2 with hydrogen peroxide. Benefits from the rich accumulation of ICG and ameliorated tumor hypoxia in the tumor sites, the enhanced generation of ROS could successfully promote the distribution of CD3+ and CD8+ T cells inside the tumors, which then lead to the amplified efficacy of PDT in both CT26 and B16F10 tumor models without causing any side effects.

Formation of MnxZny(OH)zSO4⋅5H2O – not intercalation of Zn – is the basis of the neutral MnO2/Zn battery first discharge reaction

At present there is no consensus on the charge-storage mechanism of the positive electrode in the chemistry of the MnO2/ZnSO4/Zn battery. We report the discovery of a novel, electrochemically active Mn-Zn layered double hydroxide (MnZnLDH), which, is analogous in structure to ZnLDH, and because of this similarity cannot be identified as a discharge product even by the operando XRD techniques used. We were able to synthesize MnZnLDH, for the first time, and, herein, demonstrate that its electrochemical behavior, structure, and Gibbs free energy of formation correspond to the products formed during the first discharge, providing clear evidence that this phase forms during the first discharge reaction through a conversion reaction of MnO2 and Zn2+.

A self-healing neutral aqueous rechargeable Zn/MnO2 battery based on modified carbon nanotubes substrate cathode

Rechargeable aqueous Zn/MnO2 batteries show great potential for grid-scale storage due to their low cost, high safety, and energy density, yet suffer from continuous capacity decay during operation. Therefore, this work proposes a capacity self-healing aqueous Zn/MnO2 (Zn/cCNTs-MnO2) battery using carboxyl-modified carbon nanotubes (cCNTs) as the cathode substrate, ZnSO4 + MnSO4 mixed aqueous solution as the electrolyte, and Zn foil as the anode. Based on the controllable electrodeposition reaction of MnO2, the specific capacity of Zn/cCNTs-MnO2 batteries can be achieved or recovered by operating several cycles under a low current density (0.1 mA cm−2). Then, the batteries can stably perform under a high current density (1 mA cm−2). By repeating the above steps, a capacity self-healing usage scheme was established, which can significantly improve the cycling performance of Zn/cCNTs-MnO2 batteries. Moreover, the results of the proposed Zn/cCNTs-MnO2 batteries verify the MnO2 electrodeposition mechanism and introduce a novel method for the development of durable aqueous rechargeable Zn/MnO2 batteries.

Electrochemical properties of sodium manganese oxide/nickel foam supercapacitor electrode material

Sodium manganese oxide (Na x MnO2) is supported on nickel foam (NF) substrate to prepare electroactive Na x MnO2/NF electrode material. Na x MnO2 as sodium ion pre-intercalation compound is formed through solid phase reaction of MnO2 and NaOH with optimal mole ratio of 1:2 and calcination treatment at 700 °C for 5 h. Na x MnO2 shows lower Warburg diffusion impedance and charge transfer resistance than MnO2. Na x MnO2/NF shows much higher current response than MnO2/NF due to predominant reversible redox reaction of Na x MnO2. The reversible intercalation/deintercalation of sodium ion at the deep interlayer of Na x MnO2 contributes to Faradaic capacitance. MnO2/NF and Na x MnO2/NF reveal capacitance decay from 18.5 to 4.2 F g−1 and from 133.2 to 65.7 F g−1 in 0.5 M Na2SO4 electrolyte when current density increases from 0.2 to 2.0 A g−1, indicating respective capacity retention of 22.7% and 49.3%. Na x MnO2/NF exhibits higher capacitance and better rate capacitance retention than MnO2/NF, presenting the promising supercapacitor energy storage.

Reducing substances-enhanced degradation of pollutants by permanganate: The role of in situ formed colloidal MnO2

Permanganate is one of common oxidants used for organic pollutant abatement in water treatment. This study showed that the degradation rate of bisphenol A (BPA) by permanganate at pH 5.0 in the presence of aniline is much higher than that in the absence of aniline. 2, 5, and 10 μM of aniline enhanced BPA degradation rate by 104%, 326% and 601%, respectively. Colloidal MnO2 was formed through the reduction of permanganate by aniline and contributed to BPA oxidation considerably. The reactivity of MnO2 is sensitive to pH and is high under acidic conditions, resulting in the observed enhancement of aniline on BPA removal by permanganate at pH < 7.0. The role of MnO2 was further confirmed by the relationship of MnO2 formation and BPA/aniline removal, the inhibitory effect of Ca2+ on the oxidation of BPA in the presence of aniline. Besides the aniline/BPA system, the pollutants which react with permanganate rapidly are likely to enhance the degradation of coexisting pollutants which show high reactivity towards MnO2. Due to the reduction of permanganate and stabilization of the in situ formed colloidal MnO2 by water matrix, the oxidation rate of pollutant in real water is higher than that in pure water.

Enhanced energy density and wide potential window for K incorporated MnO2@carbon cloth supercapacitor

Based on the redox couple reaction of Mn3+/Mn4+, the theoretical capacitance of manganese dioxide (MnO2) has a very high value of 1370 F/g but the specific capacitance of MnO2 in the reported literature is still under 300 F/g. The potential window of MnO2 in the previously published studies is approximately 1 V which, considering E = 1/2CV2, limits the power and energy densities far below the theoretical value. In this work, we developed an ultra-thin K+ doped δ-MnO2 nanosheets array electrode the potential window of which extended to 0–1.2 V with a highly reversible capacitance of 366 F/g. When the potential window reaches 1.2 V, the fast-redox reaction of MnO2 and the K+ intercalation/deintercalation process restrains water decomposition in kinetics. A high potency aqueous asymmetric supercapacitor (K-MnO2//AC) was drafted with K-MnO2 as a positive electrode which exhibited a stable working potential window of 0–2.2 V in 1 M Na2SO4 aqueous electrolyte. This device has demonstrated an excellent energy density of 56 Wh/kg at a power density of 550 W/kg and an ultralong cycle performance with capacitance retention of 98% over 10,000 cycles at the current density of 10 A/g. This approach leads to new prospects for emerging high workable potential window aqueous energy storage devices.

Characterization and property of magnetic ferrite ceramics with interesting multilayer structure prepared by solid-state reaction

Polyhedral MnFe2O4 with multilayer structure was successfully synthesized, and the possible originating mechanism of multilayer structure was firstly determined in current study. The phase formation, morphology evolution and interface reaction of the solid-state reaction of MnO2 and Fe2O3 mixture under air and reduction atmospheres were comparatively investigated, and the microwave absorption property of polyhedral MnFe2O4 with multilayer structure were discussed via the XRD, SEM, XPS, TEM, AFM and vector network analyzer measurements. Experiment results showed that multilayer MnFe2O4 can be synthesized both in the air at 1200–1300 °C and in 4 vol%CO at 1000–1100 °C. The reduction atmosphere was favorable to the formation of multilayer structure of MnFe2O4 due to the occurrence of multilayer MnO as the intermedium. In addition, morphology evolution demonstrated that the particle size of MnO2 after reduction was decreased remarkably which was also beneficial to the formation of MnFe2O4. However, air atmosphere is unfavorable to the generation of MnFe2O4 due to the recrystallization growth of Fe2O3 to lump impeding the element diffusion. Resultantly, the required temperature for the synthesis of MnFe2O4 in air was much higher than that in 4 vol% CO. One possible mechanism for the polyhedral MnFe2O4 with multilayer structure was based on the combination of the greater growth speed of (111) plane in the cubic MnFe2O4 crystal and terrace-ledge-kink (TLK) growth model. Moreover, multilayer MnFe2O4 prepared by the solid-state reaction presented good microwave absorbing property compared with that of the ferrites synthesized via the representative wet chemistry and combined methods.

Dual catalytic cascaded nanoplatform for photo/chemodynamic/starvation synergistic therapy

In this study, manganese dioxide (MnO2) was attached to prussian blue (PB) by a one-pot method to prepare PBMO. Then, the GOD was loaded onto PBMO through the electrostatic interaction of hyaluronic acid (HA) to form tumor-targeted nanoplatform (PBMO-GH). Hydrogen peroxide (H2O2) and gluconic acid were produced through the GOD-catalyzed enzymatic reaction. Meanwhile, PB could not only catalyze H2O2 for oxygen generation to further promote glucose consumption but also possess the property of photothermal conversion. As a result, glucose was continuously consumed to achieve the starvation therapy (ST), and the photothermal therapy (PTT) could be realized under near-infrared (NIR) light. Besides, the Mn2+ generated by the reaction of MnO2 with glutathione (GSH) could exert Fenton-like reaction to produce highly toxic hydroxyl radicals (·OH) from H2O2, which thereby realized self-reinforcing chemodynamic therapy (CDT). In vitro and in vivo experiments demonstrated that PBMO-GH could effectively inhibit the growth of tumor cells via ST/CDT/PTT synergistic effect. Therefore, the as-prepared nanoplatform for multi-modal therapy will provide a promising paradigm for overcoming cancer.

Electrochemical Evaluation of the Application of Hydrogel Electrolytes to Rechargeable Zn|MnO2 Alkaline Batteries

Zinc-manganese dioxide (Zn|MnO2) alkaline batteries have been widely studied as the active materials exhibit high theoretical capacities (820 mAh/g for Zn and 620 mAh/g for MnO2), low cost, and are inherent safety. Furthermore, the active materials are electrochemically active in aqueous alkaline electrolytes, such as potassium hydroxide (KOH), which is beneficial from a cost and safety perspective. It is widely known that one of the issues with this system is active MnO2 poisoning by zincate anions during the 2nd electron reaction of MnO2. As a result, an electrochemically inert material, ZnMn2O4 (hetaerolite), is formed, which reduces the capacity and cycle life of Zn|MnO2 batteries. Another issue is associated with high depth-of-discharge (DOD) of each material. For example, at high DOD, Zn will undergo shape change, dendritic growth and passivation, while MnO2 will form inactive phases like Mn3O4. Therefore, the 1st electron reaction range of MnO2 is normally accessed in rechargeable Zn|MnO2 batteries with low DOD.We have observed that the use of alkaline-based hydrogel electrolytes can significantly increase the cycle life of Zn|MnO2 batteries. Large-scale Zn|MnO2 cells were tested with either hydrogel or conventional alkaline electrolytes, whose nameplate capacities were 95 Ah based on the 1st electron capacity of MnO2. The hydrogel electrolytes were formed by mixing KOH solution, acrylic acid, and potassium persulfate solution as an initiator. Galvanostatic tests were carried out at cycling rates of C/20 (4.75 A) with 20% DOD of the capacity (19 Ah). The single full discharge performance to 0 V with hydrogels was compared to that with KOH aqueous electrolytes. The cell with the KOH electrolyte showed two sigmoidal curves, which means that two steps of electrochemical reactions were undergone, achieving 131 Ah. After recharging it, the single full discharge was conducted again, but nevertheless it attained less than 4 Ah to 1 V onwards. On the contrary, the cell with the hydrogel presented one sigmoidal curve with 40 Ah to 0 V, and it was continuously able to extract discharge capacities ≥28 Ah to 1 V during 40 cycles. Thus, the hydrogel electrolytes significantly enhanced the electrochemical performance of Zn|MnO2 cells, compared to conventional KOH electrolytes, the reasons for which will be discussed. The results suggest that hydrogels could help preserve active materials without the aforementioned issues and make rechargeable Zn|MnO2 batteries achieve better performance while accessing the 1st electron reaction of MnO2.

A new insight into the mechanism of carbamazepine oxidation by MnO2: Crystalline structure versus Mn(III)

Mn(III) has been regarded as the origin of oxidative reactivity of MnO2 recently, however this remains controvertible. Herein, carbamazepine (CBZ), a typical refractory pharmaceutical, was treated by δ-, α-, β-, and γ-MnO2 and the role of Mn(III) was investigated. After the removal of Mn(III) by pyrophosphate washing, the δ-MnO2 exhibited a higher kinetics rate (0.180 min−1) than the sample before washing (0.075 min−1). Dissolved Mn(III) in the forms of acetate-complex Mn(III), newly acid-dissolved Mn(III) from MnO2 solid, and in-situ generated Mn(III) showed negligible oxidative reactivity towards the oxidation of CBZ. These evidenced that Mn(III) did not play a critical role in the oxidation of CBZ. The oxidative reactivity of MnO2 with different structures for the oxidation of CBZ followed the order: δ-MnO2 >> > α-MnO2 ≈ γ-MnO2 > β-MnO2. Density functional theory calculations suggested that the crystalline plane of δ-MnO2 significantly contributed to the oxidation of CBZ, thus leading to the superior performance of δ-MnO2. A new surface reaction dominated mechanism was proposed, which implies that the oxidative reactivity of MnO2 may not result from Mn(III) as previously believed. These findings could shed light on the understanding of MnO2-involved oxidation in water treatment and natural processes.

Capacitive deionization utilizing Activated Biochar – Manganese Dioxide (AB - MD) nanocomposites for desalination applications

Faradaic electric double layer capacitor (EDLC) nanocomposites for desalination were synthesized using coconut-shell derived activated biochar (AB) and manganese dioxide (MnO2) for capacitive deionization (CDI). Three different co-precipitation methods were explored to produce the composite such as: (1) indirect liquid-phase combination (ILC) method; (2) direct liquid-phase combination (DLC) method; and (3) acid-assisted grafting oxidation combination (AGO) method. Surface characterization confirmed the presence of α-MnO2 incorporated on the mesoporous activated biochar surface (485.92 m2 g−1) for all the nanocomposites developed. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) tests show that the three methods yielded a quasi-rectangular and symmetric CV plot indicating good EDLC behavior and a steep EIS plot. The highest specific capacitance of 522.7 F g−1 at 5 mV s−1 was observed using AGO method. CDI tests under 1.2 V at varying NaCl concentrations show high capacitive performance of the synthesized electrodes. The ILC method nanocomposite exhibited superior electrosorptive performance with an electrosorption capacity of 114.11 mg g−1 at 500 ppm NaCl concentration. Due to the synergistic effects of the pseudocapacitive redox reaction of MnO2 and the outstanding double-layer charging of AB on the composite, it serves as a suitable CDI electrode for desalination.

Redox-active manganese dioxide@polypropylene hybrid separators for advanced lithium ion batteries

Polypropylene (PP) separators, popular in lithium ion batteries, suffer from poor wettability towards liquid electrolytes because of their hydrophobic surfaces. Herein, thin manganese dioxide (MnO2) layers with profuse nanopores are in situ grown on a commercial PP separator via facile reduction of KMnO4 in an acidic aqueous solution. High specific capacity is achieved by the hydrophilic MnO2@PP separator, irrespective of C-rate. Importantly, MnO2 layers have an extra capacity contribution in the potential range between 3.0 and 3.4 V. It thus results in an extremely high specific capacity of 202.5 mAh/g at 0.2 C, far above the theoretical value of the cathode LiFePO4 (170 mAh/g). The electrochemical reaction of MnO2 is involved with reversible insertion/extraction of Li+ ions, similar to that of the cathode.

Nanoparticle-Embedded Electrospun Fiber-Covered Stent to Assist Intraluminal Photodynamic Treatment of Oesophageal Cancer.

Drug-eluting stents (DESs) are promising candidates for treating human oesophageal cancer. However, the use of DESs to assist photodynamic therapy (PDT) of orthotopic oesophageal tumors is not yet demonstrated to the best of current knowledge. Herein, through an electrospinning technology it is shown that oxygen-producing manganese dioxide nanoparticles are embedded into elelctrospun fibers, which are subsequently covered onto stents. Upon implantation, the nanoparticles are gradually released from the fibers and then diffuse into the nearby tumor tissue. Then, the hypoxic microenvironment can be effectively alleviated by reaction of MnO2 with the endogenous H2 O2 within the tumor. After demonstrating the excellent PDT efficacy of the stents in a conventional subcutaneous mouse tumor model, such stents are further used for PDT treatment in a rabbit orthotopic oesophageal cancer model by inserting an optical fiber into the tumor site. Greatly prolonged survival of rabbits is observed after such intraluminal PDT treatment. Taken together, this work shows that the fiber-covered stent as a nanoparticle delivery platform can enable effective PDT as a noninvasive treatment method for patients with advanced-stage oesophageal cancer.

Experimental and Theoretical Investigation of the Effect of Oxygen Vacancies on the Electronic Structure and Pseudocapacitance of MnO2.

Defect engineering is an effective way to modulate the intrinsic physicochemical properties of materials. In this work, δ-MnO2 with oxygen vacancies is fabricated by a simple oxidation or reduction process, and the relationship between the electronic structure and pseudocapacitance is systematically studied through experimental analysis and theoretical calculations. The peaks in the Raman spectra of the as-prepared samples are shifted compared with those of pure MnO2 and the Mn3+ /Mn4+ ratio and O species content also change after the introduction of oxygen vacancies. The optimized samples exhibit a better specific capacitance of 207 F g-1 after the oxidation process and 181.4 F g-1 after the reduction treatment compared with only 143.9 F g-1 for the pure MnO2 . The samples obtained through the oxidation or reduction process also retain 93.3 or 86.4 % of the initial capacity after 5000 cycles. The excellent properties are attributed to the enhanced conductivity and increased surface reactivity or electrochemically active sites. Theoretical calculations demonstrate that the presence of oxygen vacancies leads to an increase in the density of states, which improves the redox reaction of MnO2 . This study will provide a reference for exploring and designing highperformance pseudocapacitive materials.

A Novel Dendrite‐Free Mn2+/Zn2+ Hybrid Battery with 2.3 V Voltage Window and 11000‐Cycle Lifespan

AbstractWith the increasing energy crisis and environmental pollution, rechargeable aqueous Zn‐based batteries (AZBs) are receiving unprecedented attention due to their list of merits, such as low cost, high safety, and nontoxicity. However, the limited voltage window, Zn dendrites, and relatively low specific capacity are still great challenges. In this work, a new reaction mechanism of reversible Mn2+ ion oxidation deposition is introduced to AZBs. The assembled Mn2+/Zn2+ hybrid battery (Mn2+/Zn2+ HB) based on a hybrid storage mechanism including Mn2+ ion deposition, Zn2+ ion insertion, and conversion reaction of MnO2 can achieve an ultrawide voltage window (0–2.3 V) and high capacity (0.96 mAh cm−2). Furthermore, the carbon nanotubes coated Zn anode is proved to effectively inhibit Zn dendrites and control side reaction, hence exhibiting an ultrastable cycling (33 times longer than bare Zn foil) without obvious polarization. Benefiting from the optimal Zn anode and highly reversible Mn2+/Zn2+ hybrid storage mechanism, the Mn2+/Zn2+ HB shows an excellent cycling performance over 11 000 cycles with a 100% capacity retention. To the best of the authors' knowledge, it is the highest reported cycling performance and wide voltage window for AZBs with mild electrolyte, which may inspire a great insight into designing high‐performance aqueous batteries.

Enhanced Degradation of Methyl Parathion in the Ligand Stabilized Soluble Mn(III)-Sulfite System

The ligand-stabilized soluble Mn(III) recognized as active intermediate can potentially mediate the attenuation of contaminants. In this study, the abiotic degradation behaviors of methyl parathion in the ligand stabilized Mn(III)-sulfite system were investigated. The results showed that the yield of soluble Mn(III) produced from the redox reaction of MnO2 and oxalic acid was dependent linearly on the dosage of MnO2 and caused the decomposition of methyl parathion up to 50.1% in Mn(III)-sulfite system after 30 minutes. The fitted pseudo-first-order reaction constants of methyl parathion degradation increased with the increasing of the amount of produced Mn(III) but was not effected linearly by the addition of sulfite. Other ligands, including pyrophosphate and oxalic acid, acted as effective complexing agents to stabilize soluble Mn(III), and exhibited competitive effect on methyl parathion degradation with sulfite. The formation of Mn(III)-sulfite complexes is the critical step in the system to produce abundant reactive oxygen species identified as SO3•- to facilitate methyl parathion degradation. The hydrolysis and oxidation of methyl parathion were acknowledged as two primary transformation mechanisms in Mn(III)-sulfite system. These findings indicate that naturally ligands-stabilized soluble Mn(III) can be generated and could oxidatively decompose organophosphate pesticides such as methyl parathion.

Synthesis of low temperature cured alkaline activated silicomanganese fume mortar

Silicomanganese (SiMn) fume is an industrial waste whose potency in the synthesis of alkaline activated mortar is yet to be explored. The major constituents of SiMn fume are SiO2, MnO2 and K2O. SiMn fume based mortar cured at room temperature (23 ± 2 °C) was synthesized with NaOH (NH) of varied molarity (4, 8 and 12) and Na2SiO3 (NS) as alkaline activators with different ratios of NS/NH (2, 2.5 and 3). The maximum 28-day compressive strength of room temperature cured mortar of 36 MPa was achieved with combined NH-12M and NS/NH of 2.5. Utilization of only NH activator produced a low strength (6.8 MPa) mortar compared to using the combined activators due to inability of pure alkali to form condensed oligomers required for gelation. The combination of NS and NH was more workable and produced significant strength that increased with molarity of NHaq due to proliferation of silica in the base material. SEM and XRD characterizations revealed that mortar of high molarity is more crystalline and denser with well compacted matrix compared to that of mild alkali (4 M). The crystalline phase in XRD was observed at 29.5° 2θ due to the formation of Nchwaningite (Mn2+2SiO3(OH)2·(H2O)). The strength development was due to high reactivity of MnO2 with NS, especially when the ratio of NS/NH was 2.5.