Mesoporous High Surface Area Research Articles

High Surface Area Mesoporous Cotton Crop Biochar for Enhanced Confiscation of p-nitrophenol

This research study investigates the efficacy of utilizing biochar obtained from cotton crop residues for the enhanced remediation of p-nitrophenol (PNP). Cotton crop residue-derived biochar (CCB) was prepared using 1N phosphoric acid and subsequently characterized. Batch adsorption experimental analysis were conducted to assess the optimal adsorption capacity of CCB for PNP under various conditions, including temperature, pH, interaction time, initial PNP concentration, and dosage of biochar. The results demonstrated optimal adsorption capacity of 55.38 mg/g at pH 5.0, initial PNP concentration of 100 mg L-1 , and biochar dosage of 200 mg at a room temperature of 298 K. The experimental adsorption data exhibited an excellent correlation with the Redlich-Peterson isotherm model. Analysis of the sorption kinetics revealed that the material's uptake behavior closely followed a pseudo-second-order model. Thermodynamics analysis unveiled that the adsorption of PNP onto CCB was exothermic, spontaneous, and primarily driven by enthalpy. Overall, the findings suggest that CCB exhibits promising potential as an efficient adsorbent for the remediation of aquatic environments afflicted with presence of PNP.

Preparation of Nitrogen‐Doped Graphene with Hollow Nano‐Hemispheres from FexOy@Fe‐N‐GN: Towards High Capacity and Durable Anode for Li‐Ion Batteries by Chemical Modifications

AbstractThe development of high‐performance Li‐ion battery anodes is closely dependent on understanding the effect of chemical and physical properties of active materials played in the storage mechanism. In this study, mesoporous high surface area nitrogen‐doped graphene (N‐GN) and nitrogen‐doped graphene‐coated nano‐spherical FexOy containing composite (FexOy@Fe‐N‐GN) were synthesized by a bottom‐up solvothermal process using required starting materials. Acid leaching of FexOy@Fe‐N‐GN resulted in a highly microporous structure consisting of a hollow graphene nano‐hemisphere and a large basal plane monoblock structure with 63 % N‐doped graphene and 37 % graphitic N‐doped graphene (Fe‐N‐GN). While N‐GN and FexOy@Fe‐N‐GN exhibited 310 and 571 mAh g−1 reversible capacity, respectively, after 100 cycles, Fe‐N‐GN showed 940 mAh g−1 reversible capacity through >70 % diffusion‐controlled process with beneficially lower intercalation potential below ~0.25 V and 87 % capacity retention demonstrating the impact of the chemical composition and structural properties on the capacity of carbon‐based anodes.

Hierarchical SAPO-34 Catalysts as Host for Cu Active Sites.

Cu-containing hierarchical SAPO-34 catalysts were synthesized by the bottom-up method using different mesoporogen templates: CTAB encapsulated within ordered mesoporous silica nanoparticles (MSNs) and sucrose. A high fraction of the Cu centers exchanged in the hierarchical SAPO-34 architecture with high mesopore surface area and volume was achieved when CTAB was embedded within ordered mesoporous silica nanoparticles. Physicochemical characterization was performed by using structural and spectroscopic techniques to elucidate the properties of hierarchical SAPO-34 before and after Cu introduction. The speciation of the Cu sites, investigated by DR UV-Vis, and the results of the catalytic tests indicated that the synergy between the textural properties of the hierarchical SAPO-34 framework, the high Cu loading, and the coordination and localization of the Cu sites in the hierarchical architecture is the key point to obtaining good preliminary results in the NO selective catalytic reduction with hydrocarbons (HC-SCR).

High Surface Area Mesoporous Silica Nanoparticles with Tunable Size in the Sub-Micrometer Regime: Insights on the Size and Porosity Control Mechanisms.

Mesoporous silica nanostructures (MSNs) attract high interest due to their unique and tunable physical chemical features, including high specific surface area and large pore volume, that hold a great potential in a variety of fields, i.e., adsorption, catalysis, and biomedicine. An essential feature for biomedical application of MSNs is limiting MSN size in the sub-micrometer regime to control uptake and cell viability. However, careful size tuning in such a regime remains still challenging. We aim to tackling this issue by developing two synthetic procedures for MSN size modulation, performed in homogenous aqueous/ethanol solution or two-phase aqueous/ethyl acetate system. Both approaches make use of tetraethyl orthosilicate as precursor, in the presence of cetyltrimethylammonium bromide, as structure-directing agent, and NaOH, as base-catalyst. NaOH catalyzed syntheses usually require high temperature (>80 °C) and large reaction medium volume to trigger MSN formation and limit aggregation. Here, a successful modulation of MSNs size from 40 up to 150 nm is demonstrated to be achieved by purposely balancing synthesis conditions, being able, in addition, to keep reaction temperature not higher than 50 °C (30 °C and 50 °C, respectively) and reaction mixture volume low. Through a comprehensive and in-depth systematic morphological and structural investigation, the mechanism and kinetics that sustain the control of MSNs size in such low dimensional regime are defined, highlighting that modulation of size and pores of the structures are mainly mediated by base concentration, reaction time and temperature and ageing, for the homogenous phase approach, and by temperature for the two-phase synthesis. Finally, an in vitro study is performed on bEnd.3 cells to investigate on the cytotoxicity of the MNSs.

A Simple Method for the Synthesis of High Surface Area Mesoporous Carbon Monolith via Soft Template Technique

The aim of this work was the synthesis and characterization of a mesoporous carbon monolith (MC). The MC was prepared using the soft template method. Resorcinol and formaldehyde were used as the carbon precursor and triblock copolymer Pluronic F127 as the templating agent under acidic conditions. Several techniques were used to characterize the synthesized material such as Scanning Electron Microscopy (SEM), Brunauer-Emmett-Teller nitrogen sorption measurements (BET), Powder X-Ray Diffraction (PXRD), Fourier Transform Infrared spectroscopy (FTIR), and Thermogravimetric Analysis (TGA). The work characterized the changes due to the decomposition of the template during the carbonization process to form the pores in the carbon material. The result confirmed that the mesoporous monolithic carbon prepared had a high surface area and a narrow pore size in the mesometer range.

Catalytic hydrocracking reactions of tetralin as aromatic biomass tar model compound to benzene/toluene/xylenes (BTX) over zeolites under ambient pressure conditions

The gas phase selective hydrocracking process of tetralin (biomass tar model chemical compound) into benzene, toluene and xylenes (BTX) was carried out over the H-Beta, H-Mordenite, H-USY, H-Y, and H-ZSM-5 zeolite catalysts in a packed bed reactor under applied atmospheric pressure. To the best of our scientific knowledge, this performed work presents the first systematic investigation, focused on tetralin, cracking to BTX under ambient 1bar. The highest catalytic activity and carbon deposition resistance were established over the H-ZSM-5 (SiO2/Al2O3=30) with the selectivity to the BTX of 52.2mol.% in intermediates’ liquid phase, 88.7mol.% of total conversion yield after the 4h time on stream, 370°C and gas hourly space velocity (GHSV)=530h–1, and limited site deactivation. The gas phase was analyzed and ethylene, propane, ethane and methane were identified as main gas products in the product mixture at different reaction conditions. All catalysts were characterized by BET, ICP-AES, XRD, HRSEM, NH3-TPD, and pyridine-DRIFT technique. This high catalytic performance of the H-ZSM-5 catalyst is attributed to the presence the high mesopore volume and mesopore surface area, the mild acidity and the highest Brönsted to Lewis acid sites ratio (BAS/LAS) comparing with other studied zeolite catalysts. Based on the experimental results, the reaction pathway of tetralin transformation into BTX was proposed. Hydrocracking, ring opening, ring contraction, dehydrogenation/hydrogenation, alkylation/dealkylation, isomerization, and overcracking reactions were involved. Results were consistent with the occurrence of the monomolecular reaction mechanism.

Evaluation of Cationic Methylene Blue Dye Removal by High Surface Area Mesoporous Activated Carbon Derived from Ulva lactuca

Mesoporous nano-activated carbon was prepared from green algae Ulva lactuca using zinc chloride impregnation as the activation process. The obtained activated carbon was tested as a cationic dye adsorbent which is the aim of this research work. Prepared activated carbon was characterized by FTIR, BET, t-plot, BJH, TGA, SEM, TEM and EDAX. The obtained activated carbon has 84.37% carbon content, 1486 m2/g specific surface area, 0.8891 cm3/g total pore volume, and 2.32 nm average pore diameter. The adsorption properties of the prepared activated carbon were tested using Methylene blue (MB) dye. Batch experiments were applied under different adsorption parameters like pH, adsorbent dose, initial MB dye concentration, and agitation time. Different known isotherms and kinetics models were applied to the batch experimental data of MB dye removal. It was found that the adsorption data was well fitted by Langmuir model showing a monolayer adsorption capacity of 344.83 mg/g of MB dye. Kinetic studies revealed that the MB dye adsorption by Ulva lactuca activated carbon followed pseudo-second-order model with very high correlation coefficient (R2 > 0.998). The prepared activated carbon was subjected to a total of five adsorption-desorption regeneration cycles with very small loss of its dye-adsorption capacities.

Catalytic hydrogenation, hydrocracking and isomerization reactions of biomass tar model compound mixture over Ni-modified zeolite catalysts in packed bed reactor

Gas-phase conversion of a model mixture of biomass tar (5 wt% naphthalene and 95 wt% of 1-methylnaphthalene) into 2-methylnaphthalene liquid product and ethylene and propane gas mixture was carried out over different zeolites and metal promoted zeolites in a packed-bed reactor for the first time. In the present work, a series of MFI (H-ZSM-5), BEA (H-β), FAU (H-Y, H-USY), and MOR (H-Mordenite) zeolites were investigated. The effect of Ni metal addition on the promotion of parent zeolite catalysts was studied. The most successful catalysts were characterized by BET, ICP-AES, XRD, HRSEM, STEM-HAADF, and STEM-BF with EDXS, NH3-TPD, H2-TPR, TGA, and pyridine-DRIFT techniques. The superior performance in comparison to the other studied catalysts was established over the 5 wt%Ni/H-ZSM-5 (SiO2/Al2O3 = 30) with 96.2 mol% of selectivity to 2-methylnaphthalene in the liquid phase, 90 mol% total conversion with the highest part (82.9 wt%) of ethylene and propane in the gas phase after 24 h time-on-stream. This high catalytic performance of the 5 wt%Ni/H-ZSM-5 catalyst can be attributed to the presence of the high mesopore volume, pore diameter, and high mesopore surface area, the existence of the redox active sites, and the presence of strong Lewis acid sites due to synergetic interaction between Ni metal species and zeolite acid support. Based on the product distributions observed, the reaction scheme of the conversion of biomass tar model mixture of naphthalene and 1-methylnaphthalene over studied catalysts was proposed. Our catalytic results obtained over pristine and Ni-modified zeolite catalysts shed light on the potential use of these catalysts in the biomass tar valorization process under atmospheric pressure.

Nitrogen-Doped Mesoporous Carbon Microspheres by Spray Drying-Vapor Deposition for High-Performance Supercapacitor.

Nitrogen-doped mesoporous carbon microspheres have been successfully synthesized via a spray drying-vapor deposition method for the first time, using commercial Ludox silica nanoparticles as hard templates. Compared to freeze-drying and air-drying methods, mesoporous carbon with a higher packing density can be achieved through the spray drying method. Vapor deposition of polypyrrole followed by carbonization and etching is beneficial for the generation of ultra-thin carbon network. The mesoporous carbon microspheres possess a mesopore-dominate (95%) high surface area of 1528 m2 g−1, a wall thickness of 1.8 nm, and a nitrogen content of 8 at% in the framework. Benefiting from the increased apparent density, high mesopore surface area, and considerable nitrogen doping, the resultant mesoporous carbon microspheres show superior gravimetric/volumetric capacitance of 533.6 F g−1 and 208.1 F cm−3, good rate performance and excellent cycling stability in electric double-layer capacitors.

Adsorptive desulfurization of jet fuels over TiO2-CeO2 mixed oxides: Role of surface Ti and Ce cations

A Ti0.9Ce0.1O2 oxide-based adsorbent with high surface area mesopores was studied for adsorptive desulfurization of jet fuel (JP-5: 1055 ppm-w of sulfur) using several techniques, including GC-PFPD, N2 adsorption-desorption, XRD, XPS and TPD. Ti0.9Ce0.1O2 oxide-based adsorbent effectively adsorbed sulfur and achieved the sulfur reduction of the jet fuel from 1055 ppm-w to lower than 1 ppm-w in multiple cycles of adsorption in a fixed-bed flow system. The spent adsorbent can be regenerated in-situ at the elevated temperature by using air. Some of the sulfur atom in the organic sulfur compounds could be oxidized to form sulfate species by reaction with the surface active oxygen species, while the surface (Ti4+, Ce4+) cations of adsorbent were reduced simultaneously upon adsorption of the sulfur compounds. The formed sulfate species were further removed from the surface during the oxidative regeneration step under an air flow. The deactivation of the adsorbent was potentially caused by sintering and metal cation migration on the surface.

Allyl alcohol production by gas phase conversion reactions of glycerol over bifunctional hierarchical zeolite-supported bi- and tri-metallic catalysts

The gas-phase conversion of glycerol into allyl alcohol over Fe–Mo and Cs–Fe–Mo/HZSM-5 (with SiO2/Al2O3 = 30 and 1500) zeolite catalysts in a packed-bed continuous flow reactor has been reported for the first time. To the best of our knowledge, the Cs–Fe–Mo/HZSM-5 catalyst appears to be most promising for gas-phase conversion of glycerol into allyl alcohol. The structure and catalytic performance for the glycerol conversion over bi- and tri-metallic-promoted zeolite catalysts were studied. The synthesized catalysts were characterized by ICP–AES, ICP–MS, N2 physisorption, SEM, STEM–EDX, XRD, NH3–TPD, CO2–TPD, XPS, TGA and pyridine-DRIFT techniques, which showed that differences in catalysts activity and product distribution are influenced by metal loading, changes of acid-base, and porosity. The most stable allyl alcohol selectivity achieved was 46.1 mol.% at 98.1 mol.% glycerol conversion over the 5wt.%Cs–2.5wt.%Fe–2.5wt.%Mo/HZSM-5 (SiO2/Al2O3 = 1500) catalyst achieved with 10 wt% glycerol feed at 350 °C reaction temperature after 26 h time-on-stream. The superior performance of the synthesized catalyst was attributed to the presence of the basic sites, high mesopore volume and mesopore surface area, balance between acidic-basic sites, synergetic interaction between metal species and ZSM-5 zeolite support. The reaction pathway mechanisms of glycerol to value-added allyl alcohol via the direct glycerol dehydration and hydrogen transfer mechanism over basic sites are proposed.

High Surface Area Mesoporous Silica for Hydrogen Sulfide Effective Removal

Background: Removal of sulfur-containing compounds from the aqueous environment is necessary as these compounds pose potential risks to human health, hygienic management and bring great economic losses due to fouling of resin bed and corrosion of process equipment. Objective: This work aims to study the H2S removal efficiency using high surface area mesoporous silica (MCM–41). Methods: In this study, mesoporous silica (MCM–41) with a high surface area of 1270 m2/g and high porosity of 69% was prepared by sol-gel technique. Results: The obtained MCM–41 has exhibited a superior performance in adsorbing H2S from wastewater with a maximum adsorption capacity of 52.14 mg/g. The adsorption isotherm and kinetics of the current adsorption process are best represented by Freundlich isotherm and pseudo-secondorder models, respectively. Conclusion: Therefore, MCM–41 is an excellent adsorbent for wastewater treatment applications.

Surfactant‐Free Sol–Gel Synthesis Method for the Preparation of Mesoporous High Surface Area NiO–Al2O3 Nanopowder and Its Application in Catalytic CO2 Methanation

A group of nickel‐based catalysts with different weight percentages of Ni are synthesized using a novel surfactant‐free sol–gel method, and the prepared catalysts are used in the methanation of carbon dioxide. The results indicate that the surfactant‐free sol–gel method is highly effective to prepare nickel‐based catalysts with high Brunauer–Emmett–Teller (BET) area in the range of 269.2–297.3 m2 g−1. The increment in nickel content from 15 to 30 wt% increases the size of the Ni crystals from 3.7 to 4.2 nm, weakens the interaction between nickel oxide and alumina, and improves the reducibility of the catalysts. The catalyst with 30 wt% Ni possesses the best catalytic performance in CO2 methanation reaction with 73.98% CO2 conversion and 99% CH4 selectivity at 350 °C. High catalytic stability is also observed for these catalysts.

Characterization and evaluation of mesoporous high surface area promoted Ni- Al2O3 catalysts in CO2 methanation

In this research, mesoporous high surface area Ni-Al2O3 catalysts promoted with different transition metals (Cr, Fe, Mn, Cu, and Co) were synthesized via ultrasound-assisted co-precipitation method and their performance was explored in CO2 methanation process. The promoters can affect the textural and catalytic properties of the Ni-Al2O3 catalysts to some extent. Powder X-ray diffraction (XRD), scanning electron microscopy (SEM), temperature programmed reduction with hydrogen (H2-TPR), and N2 adsorption-desorption (BET) were used for the characterization of the prepared samples. From the BET results, it was found that the incorporation of 5 wt% of the promoter into Ni-Al2O3 catalysts caused a decrease in the surface area, NiAl2O4 crystalline size and an increase in the mean pore diameter and total pore volume. Among the samples, the catalyst modified by Mn, exhibited the higher catalytic activity and selectivity towards CH4, especially at low temperatures (200–350 °C). These results could be explained by highest Ni active sites dispersion of this catalyst and enhancement of the catalyst reducibility at the low temperatures. The effect of Mn content was also evaluated and the results revealed that the Ni-Al2O3 sample modified with 3 wt% Mn with the highest BET surface area and the lowest crystalline size possessed the best catalytic performance. To further investigate the influence of ultrasonic irradiation, the optimal catalyst was prepared with a conventional co-precipitation method and its textural and catalytic properties were compared with those obtained for the catalyst prepared with the ultrasonic assisted coprecipitation method. Also, 25Ni-3Mn-Al2O3 catalyst showed a stable performance at 350 °C for 10 h in the CO2 methanation reaction.

BPB dye confined growth of surfactant-assisted mesostructured silica matrix fiber optic sensing tracers

Thermally stable surfactant modified silica nano-matrix is synthesized by the sol–gel method at low temperature. The surfactant such as cetyltrimethylammonium bromide (CTAB) assisted silica matrix is encapsulated with bromophenol blue (BPB) for sensing activities. Prepared nano-matrix consists of numerous morphological structures such as a pseudo-spherical, hierarchal and islands. The morphology of mesoporous high surface area matrices is strongly affected by CTAB, BPB dye and the aging conditions that determine the transformation from disordered silica nano-matrix morphologies to ordered encapsulated structures. Furthermore, smooth surface matrices with low surface roughness 1.2 nm, low refractive index 1.36, large pores and small dimensions of heteroatoms contribute to the stable sensing activities. The response of coated fiber optic is determined at dynamic pH range 1–12. The prepared sensor has reversibility/repeatability, stability and fast response time of approximately 0.25 s in basic media. The accuracy of sensing device measurements in household ammonia solution and the borax solution suggested that prepared device has clear potential for daily life usage.

Thermal treatment of biochar in the air/nitrogen atmosphere for developed mesoporosity and enhanced adsorption to tetracycline

For the purpose of producing carbons with developed mesoporosity, a wood biochar was thermally treated at 600–800 °C in the air/nitrogen atmosphere. The mesopore development was observed when the air flux increased to 50–90 mL/min, and the carbon product having high mesopore surface area (316 m2/g) and mesopore pore volume (0.284 cm3/g) was produced at the treatment temperature of 700 °C. The mesopores were developed mainly in the temperature holding stage of thermal treatment, with size mainly ranged from 20 to 60 Å. The carbons’ adsorption to the antibiotic tetracycline was enhanced by 5.5–9.2 folds when the air/nitrogen mixture was used instead of nitrogen atmosphere in thermal treatment, and the enhanced adsorption is positively related to the mesopore development. In general, this research provides a facile way to produce carbons with developed mesoporosity, so as to improve their adsorption to bulky organic molecules.

Synthesis of optically active bromophenol blue encapsulated mesoporous silica–titania nanomatrix: structural and sensing characteristics

Mesostructured silica-titania (ST) and bromophenol blue encapsulated silica–titania (BPB-ST) nanomatrices are synthesized by sol–gel method at low temperature. FESEM analysis shows uniform crack-free porous surface of ST matrix. EDX mapping analysis shows that the BPB species are uniformly distributed/immobilized throughout the ST matrix lattices. AFM images reveal 45.68 nm thick film with low average surface roughness ~1.27 nm, after encapsulation of BPB dye in ST matrix. TEM analysis exhibits uniform interior titania core and silica shell network, with average particle size 2.4 ± 0.4 nm for ST sample which reduced to 0.8 ± 0.3 nm after BPB encapsulation. Mesoporous high surface area 488 m2/g and pore volume of 0.55 cm3/g encapsulated matrix is found to be beneficial for sensing analysis. Transparent (67%) mesoporous nanoparticles with low refractive index 1.41 is obtained for encapsulated nanomatrix. The synthesized sensing material is fast responsive <1 sec and found to be linear for pH 3–12. High pKa value of 7.57 at 580 nm for ST-BPB leads to the broader sensitivity range, repetitive, easy-to use, and color indication system. The ability to change color in response to external stimulus makes ST-BPB a potential sensing material in food.

Mesoporous high surface area NiO synthesized with soft templates: Remarkable for catalytic CH4 deep oxidation

Mesoporous NiO nano-sheet catalysts have been successfully synthesized by hydrothermal method with polyethylene glycol (NiO-PEG) and polyvinyl pyrrolidone (NiO-PVP) as soft templates. Compared with NiO catalysts prepared with direct calcination and precipitation methods, both NiO-PEG and NiO-PVP possess a large amount of intraparticle and interparticle mesopores with different sizes, thus resulting in catalysts with much higher surface areas. As a consequence, a larger quantity of more mobile active oxygen species have been formed in these two catalysts. It is believed that the mesoporous structure, high surface area and the presence of more mobile oxygen species are the major factors improving the activity of the catalysts for CH4 deep oxidation. The formation of too much Ni3+ cations, which is induced by the Ni2+ vacancies present in the NiO crystal matrix, is harmful to the activity. With the optimal tuning of the above factors, NiO-PEG displays the highest activity to the target reaction, which is even rival to 1wt.% Pd/Al2O3 catalyst. In addition, this catalyst exhibits excellent reaction stability in the presence or absence of water vapour, and certain physical and thermal stability for the reaction. Indeed, the information provided in this work may give people some inspiration to develop catalysts without using noble metals for air emission control reactions.

N-doped mesoporous carbon by a hard-template strategy associated with chemical activation and its enhanced supercapacitance performance

Well-controlled mesoporosity is of importance for porous carbons as electrochemical electrode materials. However, the ordered mesoporous carbons prepared from the template approaches face the fact of relative low specific surface area in comparison to activated carbons. Herein, we employed a hard-template route associated with the chemical activation to prepare N-doped mesoporous carbon by co-casting of carbon and nitrogen precursors into the pore channels of mesoporous silica. The obtained activated N-doped mesoporous carbon (ANMC) material preserved the morphology and mesoporous structure of template, and meanwhile a secondary mesoporosity was introduced by the KOH activation. It was demonstrated that the dominant porosity in ANMC sample was from mesopore, and it possessed a high mesopore surface area (2505.6m2g−1) and mesopore volume (1.74cm3g−1). The N dopant was determined to be pyridinic-N, pyrrolic-N, quaternary-N and pyridine-N-oxide, which did not only contribute the pseudocapaticance but also facilitated the electron transfer in the carbon skeleton. The developed mesoporosity and N doping made this material exhibit superior electrochemical performance that was much higher than those of ordered mesoporous carbon, N-doped ordered mesoporous carbon and activated N-doped carbon samples. Also, the specific capacitance 336.9Fg−1 (0.5Ag−1) and the rate capability were higher than those of other reported mesoporous carbons. In addition, the assembled symmetrical supercapaictor simultaneously showed the high energy density and power density, as well as presented the superb cycling ability (∼98.5% capacitance retaining after 5000 runs).

Mesoporous nitrogen-doped carbon microfibers derived from Mg-biquinoline-dicarboxy compound for efficient oxygen electroreduction

An in-situ MgO-templating synthesis route was introduced to obtain the mesoporous nitrogen-doped carbon microfibers by thermal conversion of new Mg-2,2′-biquinoline 4,4-dicarboxy acid coordination compound (Mg-DCA) microfibers. The investigated crystal structure of Mg-DCA testified that the assembling of Mg2+ and DCA through Mg-O coordination bond and hydrogen bond contributed to the formation of one-dimensional (1D) crystalline Mg-DCA microfibers. The nitrogen-doped carbons derived from the pyrolysis of Mg-DCA showed the well-defined microfiber morphology with high mesopore-surface area. Such mesoporous microfibers exhibited the efficient catalytic activity for oxygen reduction reaction (ORR) in alkaline solutions with better stability and methanol-tolerance performance.