Cyclic Stability Test Research Articles

Facile Preparation of Cu2S/Cu Mesh For High‐performance Solar Water Evaporation

AbstractSolar vapor generation has attracted tremendous attention as one of the most efficient ways of utilizing solar energy. Compared with bulk heating, interfacial solar steam generation efficiency is high, and the heat loss to the surrounding environment is minimal, which is an eco‐friendly and energy‐efficient way of harvesting solar energy for desalination and wastewater treatment. So it is highly desirable to develop low‐cost and high‐efficiency solar absorbers for practical applications of interfacial solar steam generation. In this work, Cu2S/Cu mesh was prepared by depositing Cu2S nanoparticles on copper mesh by one‐step hydrothermal method, which was used as photothermal conversion material for solar interfacial evaporation. This material owns a high solar absorptivity of 84.01 % within the wavelength range of 0.25–2.5 μm. Under one sun illumination, the evaporation rate is 1.55 kg m−2 h−1 and the solar thermal conversion efficiency reaches 96.9 %. The cycle stability tests showed that the evaporation rate decreased firstly and then was balanced at 1.34 kg m−2 h−1 in 10 cycles. Furthermore, this material can maintain a stable performance of interfacial solar steam generation during desalination of seawater and purification of dye wastewater containing Rhodamine B and Methyl Orange, respectively. This work provides a low‐cost, simple, and efficient preparation method for synthesizing an efficient Cu2S/Cu mesh solar steam evaporation material.

Graphitic carbon nitride/NH2-MIL-101(Fe) composite for environmental remediation: Visible-light-assisted photocatalytic degradation of acetaminophen and reduction of hexavalent chromium

Herein, an efficient photocatalyst composed of graphitic carbon nitrate and iron-based metal-organic framework (g-C3N4/NH2-MIL-101(Fe)) composite was fabricated by a solvothermal method for the degradation of acetaminophen (AAP) and reduction of Cr(VI) under sunlight illumination. The composite was confirmed by X-ray diffraction. UV–visible spectra showed that the bare g-C3N4, pure Fe-MOF, and composite harvest solar light effectively. The photocatalytic experiment indicated that the composite exhibited superior reduction efficiency of Cr(VI) (66%) compared to the bare g-C3N4 (35%) and pure Fe-MOF (51%) at pH 7. As the pH decreases from 9 to 2, the reduction efficiency increased. The highest Cr(VI) reduction (91%) was observed at pH 2. On the other hand, the catalyst degraded 94% of AAP at pH 7 compared to the bare g-C3N4 (42%) and pure Fe-MOF (60%) in the presence of hydrogen peroxide. A radical scavenger experiment endorsed that the generation of superoxide radicals was the main reason for the AAP degradation. The cyclic stability test indicated that there was no substantial decrease in the degradation efficiency of AAP after ten repeated cycles. The kinetic studies showed that the photodegradation of AAP and reduction Cr(VI) was well-fitted to the first-order kinetics. Gas chromatography-mass spectrometry analysis showed that hydroquinone, aliphatic carboxylic acids, monohydroxy, and dihydroxy paracetamol were the main products formed as a result of such degradation process. Therefore, the iron-based MOF and their composites can be used as effective photocatalysts for pollutants degradation.

A Cathodic Electrochromic Material Based on Thick Perylene Bisimide Film with High Optical Contrast and High Stability

A Cathodic Electrochromic Material Based on Thick Perylene Bisimide Film with High Optical Contrast and High Stability

Fabrication of FTO/PNIPAm/FTO Electrical‐Thermal Dual‐Response Smart Window for Solar Radiation Management in the Full Temperature Range**

AbstractDual‐response smart window, which can respond to two external stimuli simultaneously or separately, has more solar adjustment modes and a wider range of solar radiation adjustment. In this paper, a double‐layer fluorine‐tin oxide (FTO) electrical‐thermal mold was presented, and poly(N‐isopropylacrylamide) (PNIPAm) hydrogel was encapsulated in the mold to form an electric‐thermal dual‐response smart window. The electrical response refers to the electrothermal conversion characteristics of the double‐layer FTO mold used to compensate for the insufficient thermochromic performance of the PNIPAm hydrogel when temperature is between 25 °C and 32 °C, rather than electrochromic properties. Finally, when the applied voltage reaches 5 V, the dual‐response smart window achieves a high solar modulation ability (ΔTsol) of 26.51 %. In addition, it can be concluded that a 5 V of applied voltage is adequate for the dual‐response smart window (25 mm×25 mm×2.2 mm) to exhibit excellent ΔTsol and extremely fast response speed by the test of the electrothermal conversion performance, transparency change during the heating process, and UV‐Vis‐NIR transmittance spectra. Furthermore, the thermal management tests and cyclic stability tests indicate that the smart window has a potential energy saving effect and environmental tolerance. The prepared smart window enables PNIPAm hydrogel to manage solar radiation well in the entire ambient temperature range actively or passively.

Facile synthesis of sphere-like structured ZnIn2S4-rGO-CuInS2 ternary heterojunction catalyst for efficient visible-active photocatalytic hydrogen evolution

Photocatalysis is a promising approach for generating hydrogen, an eco-friendly and cost-effective fuel. It is hypothesized that the ternary catalyst ZnIn2S4-rGO-CuInS2, prepared by ultrasonication method, should be effective for optimized photocatalytic hydrogen generation in a Na2S/Na2SO3−water mixture. The as-synthesized catalyst was characterized using various surface analytical and optical techniques. Field-emission scanning electron microscopy and high-resolution transmission electron microscopy analyses revealed that marigold-like structured ZnIn2S4 and layer-structured CuInS2 were dispersed on the reduced graphene oxide sheets. The ternary ZnIn2S4-rGO-CuInS2 system showed enhanced photocatalytic H2 production compared to pure ZnIn2S4, CuInS2, ZnIn2S4-rGO, CuInS2-rGO, and ZnIn2S4-CuInS2 catalysts under visible light illumination. The fabricated ZnIn2S4-rGO-CuInS2 catalyst afforded hydrogen generation of 2531 μmol/g after 5 h. The enhanced performance of the ZnIn2S4-rGO-CuInS2 catalyst originates from the synergetic effect with rGO as the electron transfer medium, and is confirmed by photocurrent density and photoluminescence measurements that indicate reduced recombination between the excited electron and hole pairs, and fast electron transfer in the ternary composite. The excellent performance of the ZnIn2S4-rGO-CuInS2 catalyst for up to three consecutive cycles was demonstrated in cyclic stability tests under visible-light illumination.

The Potential Use of Fly Ash from the Pulp and Paper Industry as Thermochemical Energy and CO2 Storage Material

As a part of our research in the field of thermochemical energy storage, this study aims to investigate the potential of three fly ash samples derived from the fluidized bed reactors of three different pulp and paper plants in Austria for their use as thermochemical energy (TCES) and CO2 storage materials. The selected samples were analyzed by different physical and chemical analytical techniques such as X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD), particle size distribution (PSD), scanning electron microscopy (SEM), inductively coupled plasma atomic emission spectroscopy (ICP-OES), and simultaneous thermal analysis (STA) under different atmospheres (N2, CO2, and H2O/CO2). To evaluate the environmental impact, leaching tests were also performed. The amount of CaO as a promising candidate for TCES was verified by XRF analysis, which was in the range of 25–63% (w/w). XRD results indicate that the CaO lies as free lime (3–32%), calcite (21–29%), and silicate in all fly ash samples. The results of STA show that all fly ash samples could fulfill the requirements for TCES (i.e., charging and discharging). A cycling stability test of three cycles was demonstrated for all samples which indicates a reduction of conversion in the first three reaction cycles. The energy content of the examined samples was up to 504 kJ/kg according to the STA results. More energy (~1090 kJ/kg) in the first discharging step in the CO2/H2O atmosphere could be released through two kinds of fly ash samples due to the already existing free lime (CaO) in those samples. The CO2 storage capacity of these fly ash samples ranged between 18 and 110 kg per ton of fly ash, based on the direct and dry method. The leaching tests showed that all heavy metals were below the limit values of the Austrian landfill ordinance. It is viable to say that the valorization of fly ash from the pulp and paper industries via TCES and CO2 storage is plausible. However, further investigations such as cycling stability improvement, system integration and a life cycle assessment (LCA) still need to be conducted.

One-step synthesis of nitrogen−fluorine dual-doped porous carbon for supercapacitors

The development of doped porous carbon materials has attracted much attention in the application of supercapacitors. This study reports a straightforward one-step method to prepare nitrogen−fluorine dual-doped porous carbon through direct carbonization of commercially available 2-methylimidazole and tetrafluoroterephthalonitrile in the presence of KOH. The obtained porous carbon demonstrated superb specific surface area of more than 2,000 m2 g−1 and high fluorine and nitrogen doping (> 10% in total). The obtained materials were investigated for fabrications of supercapacitive electrodes and devices. The doped carbon registered a specific capacitance of 354.4 F g−1 at 0.5 A g−1, with a capacitance retention of 72% at 10 A g−1 using H2SO4 electrolyte in a three-electrode system. In the cyclic stability test, little capacitance and Coulombic decays were observed after 5,000 cycles at 10 A g−1. An assembled symmetric supercapacitor with a voltage window of 0–1.2 V yielded a specific energy of 7.7 Wh kg−1 at 150 W kg−1 in Na2SO4 electrolyte. This work presents a new protocol for the synthesis of high-performance carbon-based materials for energy-storage applications.

Formulation and Quality Assessment of Boswellia Vaginal Gel

Background and Objectives: Over the centuries, medicinal herbs have been used as major sources of medicine for prevention and treatment of diseases;. however, herbal drugs should be converted to new dosage forms for better acceptance and easier usage by patients. The present research has been performed to formulate a herbal gel for vaginitis based on Iranian traditional medicine. Methods: The extract of oleogumresin of Boswellia was obtained using propylene glycol: water. The gel was prepared using the extract (2% and 5%), carbomer 940 (0.5% and 1%), tri-ethanolamine and distilled water. Further, the prepared gels were evaluated for physicochemical and microbial characteristics. Accelerated stability test was performed on the selected gel for six months. Results: The gel with 2% extract of Boswellia using propylene glycol: water 80:20 as the solvent and carbomer 1% was selected as the best one. The formulated gel was homogenous, white in color with acceptable physicochemical and microbial characteristics. Hexane soluble content and total acids as boswellic acid in the gel were found 0.25% and 8.7 mg/100 g, respectively. It was stable during centrifugation but it was unstable in temperature cycle test and stability test; therefore, it should be kept in cool place. Conclusion: The prepared gel contains volatile compounds with antimicrobial and anti-inflammation activities; therefore, it could be an appropriate candidate for vaginitis.

Exceptional Sodium-Ion Storage by an Aza-Covalent Organic Framework for High Energy and Power Density Sodium-Ion Batteries.

Redox-active covalent organic frameworks (COFs) are a new class of material with the potential to transform electrochemical energy storage due to the well-defined porosity and readily accessible redox-active sites of COFs. However, combining both high specific capacity and energy density in COF-based batteries remains a considerable challenge. Herein, we demonstrate the exceptional performance of Aza-COF in rechargeable sodium-ion batteries (SIBs). Aza-COF is a microporous 2D COF synthesized from hexaketocyclohexane and 1,2,4,5-benzenetetramine by a condensation reaction, which affords phenazine-decorated channels and a theoretical specific capacity of 603 mA h g-1. The Aza-COF-based electrode exhibits an exceptional average specific capacity (550 mA h g-1), energy density (492 W h kg-1) at 0.1 C, and power density (1182 W kg-1) at 40 C. The high capacity and energy density are attributed to swift surface-controlled redox processes and rapid sodium-ion diffusion inside the porous electrode. Rate capability studies showed that the battery also performs well at high current rates: 1 C (363 mA h g-1), 5 C (232 mA h g-1), 10 C (161 mA h g-1), and 20 C (103 mA h g-1). In addition, the long-term cycling stability test revealed very good capacity retention (87% at 5 C) and Coulombic efficiencies near unity over 500 cycles.

Shape Effect on Electrochemical Energy Storage Performance of Nanosized Copper Germanium Selenide Particles

Colloidal Cu2GeSe3 nanosheets (NSs) (0.5–1.5 μm) and Cu2GeSe3 nanoparticles (NPs) (8–10 nm) were synthesized for electrochemical performance comparison. The galvanostatic measurements show the maximum capacitance of 118 F/g and 77 F/g for Cu2GeSe3 NSs and NPs, respectively. Each type of nanomaterials exhibits shape dependence in its capacitance reduction behavior with increasing current density due to differences in surface area and electrical conductivity. The cyclic stability tests for Cu2GeSe3 NSs showed a capacity retention of about 90% after 1000 cycles.

Fabrication and electrochemical behavior of halloysite/ graphene-polyaniline three-dimensional hybrid aerogel loaded with iron oxide

Great progress had been made in the synthesis and application of graphene, graphene oxide (GO) aerogels, and reduced graphene oxide (rGO). However, most of the reported graphene hybrid aerogels reduced the mechanical properties of the obtained materials because of their wide pore size distribution, which limited the recycling of aerogels. Therefore, it was urgent to prepare graphene hybrid aerogels with uniform mesopores or micropores to enhance the structural stability of aerogels. Meanwhile, the mechanical and electrical properties of graphene hybrid aerogels could be further improved. In this paper, halloysite/graphene-polyaniline three-dimensional hybrid aerogel loaded with Fe3O4(HGA-PANI) was fabricated. The microstructure, mechanical properties, and electrochemical properties of HGA-PANI were characterized by scanning electron microscope (SEM), X-ray Photoelectron Spectroscopy (XPS), N2 adsorption-desorption tests, universal material testing machine, electrochemical workstation, and so on. Halloysite nanotubes (HNT) were fixed on the surface of graphene sheets or intercalated between graphene nanosheets. The three-dimensional network structure was formed, which reduced the agglomeration between graphene sheets. The hybrid of HNT and graphene sheet increased the graphene's specific surface area and constructed a three-dimensional network porous structure. Through Cyclic voltammetry (CV), Galvanostatic charge-discharge (GCD), Electrochemical impedance spectroscopy (EIS), and cycle stability tests, HGA-PANI had acceptable electrical properties, large capacitance, thin internal resistance, and amazing cyclical stability.

Synthesis and electrochemical performance of (100-x)Li7P3S11-xLi3SI composite solid electrolyte for all-solid-state lithium batteries

Li7P3S11 (LPS) solid electrolytes have great advantages, such as high lithium-ion conductivity, and can easily fabricate to make bulk-type all-solid-state lithium batteries. However, LPS has a disadvantage because of large interfacial resistance with lithium, which give a limitation for all-solid-state battery. In this study, (100-x)Li7P3S11-x Li3SI (x=0. 2 and 5) solid electrolyte composites are prepared by mechanical ball milling process. Various physiochemical analysis was carried out to confirm the proper mixing of Li7P3S1 and Li3SI solid electrolytes. The addition of Li3SI solid electrolyte, effectively influence the ionic conductivity and electrochemical properties of the Li7P3S1 solid electrolyte. The prepared Li7P3S11/Li3SI solid electrolyte composites are stable against the lithium metal anode even after 100h charge-discharging process and has stable potential window up to 10V. In particular, 98Li7P3S11-2Li3SI solid electrolyte based ASSLBs shows the highest capacity, of 110mA/g at the current density of 7.5mA g−1 (0.05 C). The charge – discharge cycle stability test also proved the Li3SI mixing to Li7P3S11 helped to maintain the capacity retention value of ∼100 % after 10 cycles. Therefore, the Li3SI into the Li7P3S11 electrolyte helps improve the electrochemical performance.

An electro-activated bimetallic zinc-nickel hydroxide cathode for supercapacitor with super-long 140,000 cycle durability

Inorganic double hydroxides are promising battery-type cathode materials for supercapacitors. Currently, the main limitation for the practical application of double hydroxides is their poor cyclic stability, which is originating from the relatively low electrical conductivity and irreversible phase transition. Herein, bimetallic zinc-nickel double hydroxide nanosheet arrays (ZNDH NSAs) are designed and assembled into an asymmetric supercapacitor with ultralong cyclic stability, demonstrating enormous potential as a high-performance cathode in practical applications. This bimetallic hydroxide is first spontaneously crystallized into two-dimensional nanosheets with thickness of ~10 nm, which ensure highly active sites for surface reactions. Then the as-prepared materials are further modified over an electro-activation process, which, as demonstrated by combining experimental evidence and computational simulation, leads to more defective oxygen, enlarged lattice, and reduced Ni valence, synergistically improving the charge transfer kinetics. Moreover, the introduction of Zn effectively suppresses phase transformation during ultralong cyclic stability tests and leads to improved conductivity of Zn-Ni hydroxide system. Therefore, the electro-activated ZNDH NSAs electrode exhibits an excellent capacitance of 6834 mF cm −2 at 3 mA cm −2 , and superior rate capability. The assembled supercapacitor delivers a record high cycling stability with zero capacitive loss after 140,000 cycles. To our knowledge, it is the best cycling performance for asymmetric supercapacitors. We demonstrate for the first time a novel “electro-activation” strategy that can substantially enhance the durability (no capacitive decay in 140,000 cycles) and charge storage performance of Zinc-Nickel double hydroxide electrode through controlled variation of activated upper potential. • An “electro-activation” strategy is demonstrated that enhance the charge storage performance of Zn-Ni hydroxide. • Electro-activation leads to more defective oxygen, reduced Ni valence, and loose porous network. • The Zn-Ni hydroxide-based supercapacitor shows zero capacitive loss after 140,000 cycles.

Highly active, selective, and stable Pd single-atom catalyst anchored on N-doped hollow carbon sphere for electrochemical H2O2 synthesis under acidic conditions

Single-atom catalysts (SACs) have recently attracted broad scientific interests due to their unique structural feature, the single-atom dispersion. Optimized electronic structure as well as high stability are required for single-atom catalysts to enable efficient electrochemical production of H2O2. Herein, we report a facile synthesis method that stabilizes atomic Pd species on the reduced graphene oxide/N-doped carbon hollow carbon nanospheres (Pd1/N-C). Pd1/N-C exhibited remarkable electrochemical H2O2 production rate with high faradaic efficiency, reaching 80%. The single-atom structure and its high H2O2 production rate were maintained even after 10,000 cycle stability test. The existence of single-atom Pd as well as its coordination with N species is responsible for its high activity, selectivity, and stability. The N coordination number and substrate doping around Pd atoms are found to be critical for an optimized adsorption energy of intermediate *OOH, resulting in efficient electrochemical H2O2 production.

Experimental Devices to Investigate the Long-Term Stability of Phase Change Materials under Application Conditions

An important prerequisite to select a reliable phase change material (PCM) for thermal energy storage applications is to test it under application conditions. In the case of solid–liquid PCM, a large amount of thermal energy can be stored and released in a small temperature range around the solid–liquid phase transition. Therefore, to test the long-term stability of solid–liquid PCM, they are subjected to melting and solidification processes taking into account the conditions of the intended application. In this work, 18 experimental devices to investigate the long-term stability of PCM are presented. The experiments can be divided into thermal cycling stability tests, tests on PCM with stable supercooling, and tests on the stability of phase change slurries (PCS). In addition to these experiments, appropriate methods to investigate a possible degradation of the PCM are introduced. Considering the diversity of the investigated devices and the wide range of experimental parameters, further work toward a standardization of PCM stability testing is recommended.

Effects of various electrolytes on the electrochemistry performance of Mn3O4/carbon cloth to ultra-flexible all-solid-state asymmetric supercapacitor

Rapid developing flexible electronics, such as flexible screens, sensors and wearable devices, make them forward to invent portable and flexible energy storage systems. Flexible supercapacitors possess quick charge-discharge, high power density, environmentally friendly and flexible characteristics, which highly cater to the growing market demands. In supercapacitors, electrolyte is one of the key factors affecting their performance. Herein, we demonstrate that a self-assembly Mn3O4/carbon cloth (Mn3O4/CC) electrode is synthesized successfully by a two-step hydrothermal method. In a three electrodes system, the Mn3O4/CC electrode is tested in Na2SO4 and KOH respectively. The results reveal that Mn3O4/CC exhibits higher specific capacitance (555 mF cm−2 at 1 mA cm−2) and lower internal resistance in KOH. On the other hand, it expresses nearly no loss in the cycle stability test (99% retention after 2000 cycles) in Na2SO4. The all-solid-state asymmetric supercapacitor presents a maximum energy density reaching 25 μWh cm−2 with a power density of 0.64 mW cm−2. It also presents ultra-high flexibility (bending and twisting for 200 times) and superior cycling performance (99.3% after 2000 cycles). Hence, the Mn3O4/CC electrode is of great prospect in the application of flexible electronic devices.

In-situ crystalline infiltrated Mo2C@C for efficient hydrogen evolution reaction

Molybdenum carbide (Mo2C) is a promising electrocatalyst for hydrogen evolution reaction (HER) due to the similar electron orbital structure to platinum. Preparing Mo2C catalyst in nanoscale increases the exposure of active catalyst site and significantly enhances electrochemical reaction and improve HER performance. However, Mo2C is not a good electron conductor which still requires a more sufficient contact between the catalyst and electrode to transfer electron current. Here, we proposed in-situ Mo2C growth on carbon nanotubes (CNTs) by using wet impregnation of ammonium molybdate tetrahydrate as Mo source, which established a crystalline transition contact between Mo2C and CNTs and significantly improved HER performance. Our results further showed the optimized HER performance of Mo2C@Camt and achieved a lower Tafel slopes and low onset potential (ηonset) of 46.7 mV dec−1, 51.3 mV dec−1 and 73 mV and 127 mV (vs. RHE) under alkaline and acidic condition, respectively. Furthermore, Mo2C@Camt also shows less attenuation after 1000 times of cyclic voltammograms (CV) cycling stability test and 25 h continuous operation under alkaline and acidic condition.

Cost-effective synthesis of NiCo2O4@nitrogen-doped carbon nanocomposite using waste PET plastics for high-performance supercapacitor

A cost-effective bimetallic NiCo2O4@nitrogen-doped carbon (NC) nanocomposite was prepared through bimetallic nickel/cobalt metal organic frameworks (Ni/Co-MOF) by employing a smart approach to utilize the waste Polyethylene terephthalate (PET) plastics for energy storage applications. The NiCo2O4@NC nanocomposite was characterized successfully using analytical techniques. The nanocomposite comprises high surface area (813 m2 g− 1) and mesoporosity (~ 15 nm). NiCo2O4@NC nanocomposite demonstrates excellent electrochemical performance with high specific capacitance of ~ 890 F g− 1 at 5 mV s− 1 and ~ 913 F g− 1 at 1 A g− 1 in 6 m KOH electrolyte. The cyclic stability tests confirm excellent retention capacity (~ 99%) with fifty cyclic segments. Low-cost, environmental friendly approach, and rich redox activity of NiCo2O4@NC nanocomposite make it an alternate potential electrode material for energy storage devices.

Enhancement of supercapacitance of reduced graphene oxide, copper oxide and polyaniline using the mixture of methane sulphonic acid and sulphuric acid as electrolyte

The mixture of mineral acid and organic acid as aqueous electrolyte for the rGO12%: Cu2O/CuO40%: PANI48% (G12CP) nanocomposite, exhibited superior energy storage performance. The acid mixture electrolyte used is 0.4 M H2SO4 + 0.4 M CH3SO3H (1:1) (SA + MSA) and it exhibited enhanced diffusion and kinetic features in comparison with the bare 0.4 M H2SO4 (SA) and 0.4 M CH3SO3H (MSA). SA + MSA provided 16.8% higher energy storage than the SA and the performance obtained after 5000 charge/discharge cycles is 276.98% higher than the performance obtained before the cyclic stability test using the same acid mixture electrolyte. The G12CP provided a specific capacitance (Cs) of 490.19 F g−1, an energy density (E) of 98.0392 W h kg--1 and a power density (P) of 1.500l kW kg−1 at 1 A g−1 in the presence of SA + MSA. The obtained E is comparable with E of Li-ion batteries, Ni-metal hydride batteries, Na-S batteries, and Na-metal chloride batteries.

The Influence of Residual Sodium on the Catalytic Oxidation of Propane and Toluene over Co3O4 Catalysts

A series of Co3O4 catalysts with different contents of residual sodium were prepared using a precipitation method with sodium carbonate as a precipitant and tested for the catalytic oxidation of 1000 ppm propane and toluene at a weight hourly space velocity of 40,000 mL g−1 h−1, respectively. Several techniques were used to characterize the physicochemical properties of the catalysts. Results showed that residual sodium could be partially inserted into the Co3O4 spinel lattice, inducing distortions and helping to increase the specific surface area of the Co3O4 catalysts. Meanwhile, it could negatively affect the reducibility and the oxygen mobility of the catalysts. Moreover, residual sodium had a significant influence on the catalytic activity of propane and toluene oxidation over the synthesized Co3O4 catalysts. The catalyst derived from the precursor washed three times presented the best activity for the catalytic oxidation of propane. The origin was traced to its better reducibility and higher oxygen mobility, which were responsible for the formation of active oxygen species. On the other hand, the catalyst obtained from the precursor washed two times exhibited better performance in toluene oxidation, benefitting from its more defective structure and larger specific surface area. Furthermore, the most active catalysts maintained constant performance in cycling and long-term stability tests of propane and toluene oxidation, being potentially applicable for practical applications.