Commercial Co3O4 Research Articles

Catalytic reduction of bromate by Co-embedded N-doped carbon as a magnetic Non-Noble metal hydrogenation catalyst

While catalytic hydrogenation of bromate represents a useful technique for eliminating carcinogenic bromate, expensive noble-metal catalysts and excessive H2 gas are usually required, impeding large-scale implementation of this technique. As borohydride is an alternative source for releasing H2 in a more controllable way and non-noble metal catalysts (e.g., Co) can catalyze hydrolysis of borohydride to generate H2, it is promising to employ Co and borohydride for hydrogenation of bromate. Moreover, it is even more practical to develop heterogeneous catalysts with magnetism for easier handle and recovery of catalysts. Therefore, the aim of this study is to develop such a magnetic heterogeneous catalyst for bromate reduction by using borohydride. Herein, a special Co-based catalyst is fabricated by transforming Co-substituted prussian blue analogue into Co-embedded N-doped carbon ([email protected]) composite through carbonization. [email protected] also exhibits a higher catalytic activity for reducing bromate than the commercial Co3O4 as [email protected] could accelerate hydrolysis of NaBH4 to generate H2 gas much faster. The activation energy (Ea) of bromate reduction by [email protected] is also much lower than the reported Ea. [email protected] could still completely remove bromate and reduce it to bromide under alkaline conditions, and [email protected] also exhibit a very high selectivity towards bromate reduction in the presence of other anions. Moreover, [email protected] could be also reused for multiple-cycles to continuously reduce bromate to bromide. These features demonstrate that [email protected] is certainly an advantageous and convenient heterogeneous catalyst for reducing bromate in water.

Doping phosphorus into Co3O4: A new promising pathway to boost the catalytic activity for peroxymonosulfate activation

Recently, Co3O4 has been widely utilized as heterogeneous catalyst for peroxymonosulfate (PMS) activation to eliminate various organic pollutants. However, for practical applications, the catalytic efficiency of pure Co3O4, limited by its simple monometal oxide component, needs further improvement. In a departure from the conventional doping method employing metal elements as dopants, herein, it is demonstrated that non-metal element doping offers a new and promising avenue to optimize the property of Co3O4 and thus improve its catalytic performance. This was exemplified by phosphorus (P)-doped Co3O4 (P-Co3O4), which was obtained by a simple low-temperature annealing of commercial Co3O4 using NaH2PO2 as the P source. Noticeably, owing to the presence of P dopants (0.15 wt%), the cobalt sites in P-Co3O4 exhibited higher affinity, easier electron transfer, and stronger bond-weakening ability for PMS relative to those in non-doped Co3O4, which led to a boosted catalytic activity. The degradation of rhodamine B (RhB) by P-Co3O4/PMS was verified to be SO4−- and 1O2-dominated and underwent a multistep mineralization pathway, and its kinetic rate constant (0.139 min−1) was 4.5 times that (0.031 min−1) of RhB degradation by Co3O4/PMS. Moreover, the P-Co3O4 exhibited excellent reusability, without obvious catalytic activity loss after six successive runs. Our work presents an unconventional strategy for designing cost-effective and efficient heterogeneous cobalt-based catalysts for PMS activation.

Precise Construction of Stable Bimetallic Metal–Organic Frameworks with Single-Site Ti(IV) Incorporation in Nodes for Efficient Photocatalytic Oxygen Evolution

Precise Construction of Stable Bimetallic Metal–Organic Frameworks with Single-Site Ti(IV) Incorporation in Nodes for Efficient Photocatalytic Oxygen Evolution

Nature of the Pt-Cobalt-Oxide surface interaction and its role in the CO2 Methanation

Based on our previous investigations, it turned out that the Co3O4 material is a promising catalyst in the ambient pressure CO2 methanation. This work aims at understanding the Pt-Cobalt-Oxide surface interaction and its effect on the catalytic performance. The incorporation of Pt nanoparticles into the mesoporous Co3O4 (Pt/m-Co3O4) and commercial Co3O4 (Pt/c-Co3O4) improves the catalytic activity of both catalysts by a factor of ∼ 1.4 and ∼ 1.9 respectively at 673 K. The same tendency towards the increased basicity was also observed. Morphology-induced surface basicity was previously shown to play a key role in determining the catalytic activity of free-standing supports. From HR-TEM (-EDX), EXAFS, CO2-TPD, and CO chemisorption measurements it was established that during the pre-treatment, Co-Pt alloy particles partially covered by the CoxOy layer are formed. It has been postulated that this structure transformation generates new basic centres, the amount of which per unit surface area is significantly larger for Pt/c-Co3O4 and this in turn is responsible for the higher enhancement effect of the Pt/c-Co3O4 catalyst in the CO2 methanation. This study emphasizes the importance of the surface structure exploration for the dynamic catalytic systems in order to reach maximum activity and selectivity in the CO2 methanation.

Superior thermochemical energy storage performance of the Co3O4/CoO redox couple with a cubic micro-nanostructure

Co3O4 has been regarded as one of the most promising materials for redox energy storage due to its high theoretical conversion and complete redox reversibility. However, when undergoing charge-discharge cycles at high temperature, the material becomes sintered. The reversibility of the cobaltous oxides highly deteriorates, and the reoxidation reaction rate notably decreases. In addition, the obvious thermal hysteresis in the redox reaction process also limits the energy storage performance of the material. In this work, Co3O4 with different micro-nanostructured morphologies is synthesized to evaluate its thermochemical energy storage performance. The capacity of the synthesized and commercial Co3O4 is tested by thermogravimetric analysis (TGA). The fresh and recycled oxides are well characterized. Results suggest that all samples show complete reversibility, and the conversion decreases slightly after 30 cycles. The synthesized samples show better performance, especially cubic Co3O4. The reoxidation rate of the commercial sample is approximately 150 μmol/min/g, but that of the cubic sample is approximately 300-200 μmol/min/g in the first five cycles. The oxidation rate of the cubic sample decreases and finally remains at about 180 μmol/min/g from the 5th cycle to the 30th cycle. After 5 charge-discharge cycles, the commercial Co3O4 is severely sintered, while the cubic oxides are only slightly sintered. After 30 redox cycles, the morphology of commercial oxides completely changed, while that of the cubic oxide retains the approximate shape of a cube. Moreover, the thermal hysteresis values of the commercial and cubic Co3O4 are 24.7°C and 10.1°C, respectively, suggesting that the energy loss of cubic oxides is much smaller. The higher exothermic temperature of the cubic Co3O4 redox process also indicates that it can supply high-grade thermal energy.

Two-dimensional ultrathin perforated Co3O4 nanosheets enhanced PMS-Activated selective oxidation of organic micropollutants in environmental remediation

Here a two-dimensional (2D) ultrathin perforated Co3O4 nanosheet is rationally designed by a wet-chemical synthesis to activate peroxymonosulfate (PMS) for efficient selective oxidation. And the physicochemical properties of catalyst were investigated by series of techniques. The Co3O4 nanosheets achieved a 98.0% degradation efficiency of bisphenol A (BPA) within 30 min, showing a 4 times higher kinetic constant (0.112 min−1) and 5 times lower Co2+ leakage (6.5 μg/L), than commercial Co3O4 microspheres. The great enhancement in catalytic performance was ascribed to the large surface area and pore diameter in porous 2D structure, as well as the strong electrostatic attraction with PMS. Moreover, the influence of several parameters such as initial pH, temperatures, humic acids and inorganic anions in the system on the remaval of BPA were systematically studied. Since sulfate radicals (SO4−) were proved to be the primary reactive oxygen species by EPR measurements and quenching experiments, the PMS/Co3O4 nanosheets exhibits a highly selective oxidation on aromatics with electron donating groups (i.e., –OH and –CH3), while a relatively low value for organics with electron-withdrawing groups (e.g., –NO2 and –COOH). A high ionization potential threshold was determined to be greater than 9.39 eV, corresponding to a high oxidation ability to react with the organics. Finally, possible degradation pathways were proposed based on twenty intermediate products determined from mass spectrometry.

Ultrafine cobalt nanoparticle-embedded leaf-like hollow N-doped carbon as an enhanced catalyst for activating monopersulfate to degrade phenol

While cobalt (Co) stands out as the most effective non-precious metal for activating monopersulfate (MPS) to degrade organic pollutants, Co nanoparticles (NPs) are easily aggregated, losing their activities. As many efforts have attempted to immobilize Co NPs on supports/substrates to minimize the aggregation issue, recently hollow-structured carbon-based materials (HSCMs) have been regarded as promising supports owing to their distinct physical and chemical properties. Herein, in this study, a special HSCM is developed by using a special type of ZIF (i.e., ZIF-L) as a precursor. Through one-step chemical etching with tannic acid (TA), the resultant product still remains leaf-like morphology of pristine ZIF-L but the inner part of this product becomes hollow, which is subsequently transformed to ultrafine Co-NP embedded hollow-structured N-doped carbon (CoHNC) via pyrolysis. Interestingly, CoHNC exhibits superior catalytic activities than CoNC (without hollow structure) and the commercial Co3O4 NPs for activating MPS to degrade phenol. The Ea value of phenol degradation by CoHNC + MPS was determined as 44.3 kJ/mol. Besides, CoHNC is also capable of effectively activating MPS to degrade phenol over multiple-cycles without any significant changes of catalytic activities, indicating that CoHNC is a promising heterogeneous catalyst for activating MPS to degrade organic pollutants in water.

Defect-engineered Co3O4 with porous multishelled hollow architecture enables boosted advanced oxidation processes

Developing high-efficiency catalysts for advanced oxidation processes (AOPs) is significant for eliminating environmental pollutants. Herein we highlight rational architectural design coupled with defect engineering over catalyst promises advanced catalysis. Take widely-used Co3O4 as model material, we present defect-engineered Co3O4 with porous multishelled hollow architecture (MS-VO-Co3O4) for considerably boosted degradation of recalcitrant organics via peroxymonosulfate (PMS) activation. The special morphology regarding pore-abundant multi-shells with complex nanoconfined interior space contributes to active site exposure and mass diffusion. Significantly, theoretical calculations disclose that oxygen vacancies (VO) engineering can modulate surface electronic state, giving rise to strengthened binding energy and intensified electron transfer for PMS activation. Consequently, up to 46 times of catalytic enhancement can be achieved for MS-VO-Co3O4 relative to commercial Co3O4 towards 4-chlorophenol degradation (0.186 vs 0.004 min−1). This work would inspire more elegantly designed catalysts via architecture and defect engineering for various applications beyond AOPs.

Postsynthetic incorporation of catalytically inert Al into Co3O4 for peroxymonosulfate activation and insight into the boosted catalytic performance

Herein, we reported postsynthetic incorporation of generally believed catalytically inert Al3+ ion into the lattice of commercial Co3O4 to form a series of Al doped Co3O4 (ACO) catalysts, and demonstrated that the Al incorporation with suitable concentration could induce a surprising boost in activation of peroxymonosulfate (PMS). Unlike conventional direct synthesis that might lead to the formation of bimetallic spinel oxides in an uncontrollable manner, the presented method could produce ACO catalysts with almost unchanged particle size and morphology, which was beneficial for a reliable assess on the composition-dependent catalytic performance to avoid possible misjudgment caused by other factors. More importantly, the Al incorporation could not only promote the adsorption affinity and electron transfer ability of Co to PMS but also facilitate the OO bond cleavage of the adsorbed PMS, thereby leading to an enhanced catalytic ability. As a result, the optimal ACO (Co2.98Al0.02O4) exhibited a high degradation efficiency with a rate constant (0.127 min−1) 2.6-folds that of pure Co3O4 (0.049 min−1) in PMS activation for degradation of metronidazole (MNZ). Besides, Co2.98Al0.02O4 manifested low cobalt leaching (≤79 μg L–1). Both degradation pathway and catalytic mechanism were proposed comprehensively, and the superb reusability of Co2.98Al0.02O4 was also confirmed. This study enriches the current synthesis methodology for bimetallic spinel oxides and provides new insights into inert metal-promoted heterogeneous cobalt-based catalysis for robust advanced oxidation processes.

Catalytic degradation of oxytetracycline via FeVO4 nanorods activating PMS and the insights into the performance and mechanism

In this work, FeVO4 nanorods were successfully synthesized and employed as peroxymonosulfate (PMS) activators for oxytetracycline (OTC) degradation. The obtained FeVO4 nanorods exhibited excellent catalytic performance for PMS activation because of the synchronous transformations of Fe3+/Fe2+, V5+/V4+ and Fe3+/V4+, and abundant adsorbed oxygen (Oads). Almost 100% of OTC can be decomposed via FeVO4 activating PMS in 40 min and the reaction rate constant (k) was 0.1073 min−1, being 5.65 times of commercial Co3O4 (0.0219 min−1). Meanwhile, FeVO4 exhibited a good stability and reusability. In addition, the impacts of experimental parameters (catalysts and PMS dosage, temperature, pH, and co-existing anions) on OTC degradation were detected in detail. It was proved that •O2−, •OH and 1O2 were generated and the contribution role in OTC degradation followed the sequence” •OH >1O2 ≈ •O2−. The possible mechanism of PMS activation by FeVO4 was deeply explored and the OTC degradation pathway was deduced according to the detected degradation intermediates. This study develops one new environmental-friendly, low cost, high efficiency and stable PMS activator for the efficient removal of antibiotics.

Hollow POM@MOF-derived Porous NiMo6 @Co3 O4 for Biothiol Colorimetric Detection.

Developing highly active and sensitive peroxidase mimics for L -cysteine (L -Cys) colorimetric detection is very important for biotechnology and medical diagnosis. Herein, polyoxometalate-doped porous Co3 O4 composite (NiMo6 @Co3 O4 ) was designed and prepared for the first time. Compared with pure and commercial Co3 O4 , NiMo6 @Co3 O4 (n) composites exhibit the enhanced peroxidase-mimicking activities and stabilities due to the strong synergistic effect between porous Co3 O4 and multi-electron NiMo6 clusters. Moreover, the peroxidase-mimicking activities of NiMo6 @Co3 O4 (n) composites are heavily dependent on the doping mass of NiMo6 , and the optimized NiMo6 @Co3 O4 (2) exhibits the superlative peroxidase-mimicking activity. More importantly, a sensitive L -Cys colorimetric detection is developed with the sensitivity of 0.023 μM-1 and the detection limit at least 0.018 μM in the linear range of 1-20 μM, which is by far the best enzyme-mimetic performances, to the best our knowledge.

In situ transformation of 3D Co3O4 nanoparticles to 2D nanosheets with rich surface oxygen vacancies to boost hydrogen generation from NaBH4

Despite substantial progress in various application fields of polyoxometalates (POMs), the use of POMs as ligands to alter the structure of solid catalysts in heterogeneous catalysis requires additional efforts. Herein, we used the reduced α-SiW12O404- (RSTA) as an inorganic ligand to mediate Co3O4 nanoparticles that efficiently promote the hydrolysis of NaBH4 to generate hydrogen with multiple activities (4747 mL/(gcat·min)) compared with NaBH4-pretreated Co3O4 (1236 mL/(gcat·min)), pristine Co3O4 (inactive) and commercial Co3O4 (inactive) at 25℃. RSTA induced both electronic and morphology effects on Co3O4 through in situ driving 3D Co3O4 nanoparticles to 2D Co3O4 nanosheets with rich surface oxygen vacancies or Co2+ during the hydrolysis process. This modulation by RSTA allowed more active sites, including both electron-rich Co0 and electron-deficient Co2+, facilitating BH4- and H2O adsorption and thus hydrogen generation. The promoted mechanism of the RSTA on both the microstructure and the catalytic performance was further proposed.

Activation of peroxymonosulfate by metal–organic frameworks derived Co1+xFe2−xO4 for organic dyes degradation: A new insight into the synergy effect of Co and Fe

Metal–organic frameworks (MOFs) derived CoFe2O4 is regarded as a promising catalyst in pollutants control due to its good performance for peroxymonosulfate (PMS) activation. However, the study towards organic dyes degradation is rare and the mechanism of the synergy effect of Co and Fe is not clarified. Herein, the MOFs derived M-Co1+xFe2−xO4 with more Co(III) in octahedral sites was prepared and used to degrade organic dyes by activating PMS. Under optimized conditions, the Rhodamine B (RhB) degradation kinetics rate of M-Co1+xFe2−xO4 is 0.260 min−1, which is 20 times higher than the commercial Co3O4 (0.013 min−1). SO4•- plays the vital role in RhB degradation and the contribution of Co(III) in octahedral sites is greater than that of Fe for PMS activation. Under weak acidic condition (pH 5), the effect of surface adsorbed OH- on PMS activation is negligible meanwhile the valence conversion of Fe is absent, implying the mechanism of synergy effect of Co and Fe under such condition is different from what was previously reported. This work would shed lights on understanding the origin of the activity of CoFe2O4 in PMS activation and developing PMS-based technologies for organic dyes wastewater treatment.

Ordered macroporous Co3O4-supported Ru nanoparticles: A robust catalyst for efficient hydrodeoxygenation of anisole

A three-dimensional ordered macroporous Co3O4 (OM-Co3O4) supported Ru catalyst was developed for the efficient hydrodeoxygenation (HDO) of anisole. It is revealed that small-sized Ru nanoparticles evenly distributed over the surface of OM-Co3O4 with large quantities of oxygen vacancies could strongly capture Ru0 species, thereby resulting in strong Ru-Co3O4 interactions. Compared with commercial Co3O4 supported Ru catalyst, Ru/OM-Co3O4 displays a better catalytic HDO performance, with a high cyclohexane yield of 92.4% at 250 °C and 0.5 MPa hydrogen pressure after 5 h on stream. Such a significant efficiency of Ru/OM-Co3O4 is mainly attributed to both high dispersion of Ru0 species and an enhanced formation of surface defects, as well as the unique macroporous framework of OM-Co3O4 support.

Metal-complexed covalent organic frameworks derived N-doped carbon nanobubble–embedded cobalt nanoparticle as a magnetic and efficient catalyst for oxone activation

While Cobalt nanoparticles (Co NPs) are useful for catalytic Oxone activation, it is more advantageous to embed/immobilize Co NPs on nitrogen-doped carbon substrates to provide synergy for enhancing catalytic performance. Herein, this study proposes to fabricate such a composite by utilizing covalent organic frameworks (COF) as a precursor. Through complexation of COF with Co, a stable product of Co-complexed COF (Co-COF) can be synthesized. This Co-COF is further converted through pyrolysis to N-doped carbon in which cobaltic NPs are embedded. Owing to its well-defined structures of Co-COF, the pyrolysis process transforms COF into N-doped carbon with a bubble-like morphology. Such Co NP-embedded N-doped carbon nanobubbles (CoCNB) with pores, magnetism and Co, shall be a promising catalyst. Thus, CoCNB shows a much stronger catalytic activity than commercial Co3O4 NPs to activate Oxone to degrade toxic Amaranth dye (AMD). CoCNB-activated Oxone also achieves a significantly lower Ea value of AMD degradation (i.e., 27.9 kJ/mol) than reported Ea values in previous literatures. Besides, CoCNB is still effective for complete elimination of AMD in the presence of high-concentration NaCl and surfactants, and CoCNB is also reusable over five consecutive cycles.

Superior performance of ZnCoOx/peroxymonosulfate system for organic pollutants removal by enhancing singlet oxygen generation: The effect of oxygen vacancies

Combination of sulfate radical (SO4−) and singlet oxygen (1O2) could enhance the removal of organic pollutants in PMS activation because of the high-selective oxidation of electrophilic compounds by 1O2. Co oxides are highly active towards PMS activation, but improving the generation of 1O2 in PMS activation with Co oxides as catalysts remains a great challenge. Herein, the Zn doped Co oxides (ZnCoOx) was prepared by calcining Zn doped ZIF-67 in air. The oxygen vacancies content of ZnCoOx could be adjusted by controlling Zn doping level and the presence of oxygen vacancies leads to the generation of 1O2 in ZnCoOx/PMS system. The optimized ZnCoOx-2 presents the kinetic constant of 0.538 min−1 for Rhodamine B removal, which is 14.2 times higher than that of undoped sample and 38.4 times higher than that of commercial Co3O4. 1O2 and SO4− exist in ZnCoOx/PMS system while 1O2 plays the dominant role for pollutants removal. The oxygen vacancies of ZnCoOx are demonstrated to be responsible for the generation of 1O2 and the mechanism is further investigated. This study provided an efficient catalyst to combine the advantages of 1O2 and SO4− for pollutants removal by PMS activation, and the results could open a new avenue for development of heterogeneous catalysts for PMS activation.

Electrospun cobalt ferrite nanofiber as a magnetic and effective heterogeneous catalyst for activating peroxymonosulfate to degrade sulfosalicylic acid

While Co3O4 nanoparticles (NPs) are frequently employed for activating peroxymonosulfate (PMS) to degrade organic contaminants, Co3O4 NPs are easily aggregated and difficult to recover from water; thus cobalt ferrite (CoFe2O4) has been considered as a magnetically-controllable alternative to Co3O4. Moreover, CoFe2O4 can be fabricated into high-aspect-ratio nanofibrous structures to configure NPs into fibrous morphologies for preventing aggregation but exhibiting superior textural properties with. Therefore, the aim of the study is to develop such a CoFe2O4 nanofiber (CFNF) through the electrospinning technique as a magnetic catalyst for activating PMS to degrade SUA. The resultant CFNF consists of CoFe2O4 NPs configured to the fibrous structure in CFNF for enabling CFNF to possess advantageous morphology, and textural properties. Thus, CFNF exhibits a higher catalytic activity for activating PMS to degrade SUA than the typical commercial Co3O4 NP as SUA was completely eliminated by CFNF-activated PMS in 45 min with kobs = 0.08 min−1, whereas Co3O4 NP-activated PMS merely eliminated ~20% of SUA. The Ea of SUA degradation by CFNF-activated PMS was 24.6 kJ/mol, which is significantly lower than reported Ea values by other catalysts, and CFNF could be reused 5 times without loss of catalytic activities. These features certifies that CFNF is a promising magnetic catalyst for activating PMS to degrade emerging contaminants. The fabrication of CFNF demonstrated here also provides a facile protocol to fabricate fibrous structures of CoFe2O4 for environmental catalytic applications.

Three-dimensional hierarchical Ca3Co4O9 hollow fiber network as high performance anode material for lithium-ion battery

Transition metal oxides have high specific capacity as anode materials for lithium-ion battery. But aggregation of particles and volume expansion during lithiation/delithiation restrict their application. In this work, a three-dimensional hierarchical Ca3Co4O9 hollow fiber network assembled by nanosheets is prepared by a electrospinning combining with heat treatment method to overcome these issues and to boost its lithium storage performance. As-synthesized sample possesses excellent cyclic stability (578.6 mA h g−1 at 200 mA g−1 after 500 cycles) and rate performance (293.5 mA h g−1 at 5000 mA g−1), much better than those of commercial Co3O4. Furthermore, the fast kinetics of the three-dimensional Ca3Co4O9 hollow fiber network is also confirmed by the variable scan rates CV tests and the EIS measurements, which is dedicated to the specific hierarchical hollow fiber network structure that provides shorter ion transport distances and higher electrical conductivity. This work supplies a universal approach to improve the electrochemical performance of transition metal oxides for lithium ion batteries.

Cobalt-based coordination polymer-derived hexagonal porous cobalt oxide nanoplate as an enhanced catalyst for hydrogen generation from hydrolysis of borohydride

As cobalt is an effective metal for catalyzing hydrolysis of NaBH4 to produce H2, Co3O4 is a proven catalyst for facilitating NaBH4 hydrolysis. Since Co3O4 can be designed into various morphologies, 2-dimensional plate-like Co3O4 can offer large contact surfaces. If the planar surfaces can be even porous, forming porous Co3O4 nanoplate (PCNP), this PCNP would be a promising catalyst for HG. Therefore, in this study, a facile approach is developed to fabricate such a PCNP for H2 generation (HG) from NaBH4 hydrolysis. Specifically, a cobaltic hexagonal nanoplate-like coordination polymer, which is synthesized via coordinating Co2+ with thiocyanuric acid (TA), is adopted as a precursor. Through calcination, Co-TA (CTA) is transformed into hexagonal nanoplate-like Co3O4 with pores to become PCNP. More importantly, PCNP showed quite different surficial reactivity and textural properties from commercial Co3O4 nanoparticle (Co3O4 NP), enabling PCNP to possess a much more superior catalytic activity towards HG from NaBH4 hydrolysis. PCNP also showed a comparatively low Ea of 35.12 kJ/mol in comparison with the reported catalysts, even precious metal catalysts, and it could be reused up to 10 cycles for HG with stable catalytic activities. These features confirm that PCNP is an advantageous catalyst for HG from NaBH4 hydrolysis.

Carbon-coated Co3O4 with porosity derived from zeolite imidazole framework-67 as a bi-functional electrocatalyst for rechargeable zinc air batteries

The electro-catalytic performance of the bi-functional catalysts at the air cathode for the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) plays a significant role for the development of rechargeable zinc air batteries (ZABs). To obtain the high-performance electrocatalysts, a series of porous Co3O4 samples derived from zeolitic imidazolate framework-67 (ZIF-67) are prepared by one-step annealing process at different temperature (350, 450, and 550 °C) under air atmosphere. Compared with the commercial Co3O4, the optimized sample Co3O4 prepared at 450 °C (CO3O4/C-450) exhibits the lowest overpotential of 1.68 V and the highest half-wave potential of − 0.56 V because the porosity of as-prepared Co3O4 provides abundant reactive sites. Moreover, the high discharge potential of 1.33 V and long cycle life of more than 100 h at 20 mA cm−2 are achieved in ZABs with CO3O4/C-450 electrocatalyst, which are attributed to the better stability provided by the carbon coating.