This study was conducted to investigate the air oxygen content inside and outside a Phyllostachys edulis forest in Qishan Forest Park throughout all four seasons.(1)Regarding the overall annual variation in oxygen con...This study was conducted to investigate the air oxygen content inside and outside a Phyllostachys edulis forest in Qishan Forest Park throughout all four seasons.(1)Regarding the overall annual variation in oxygen content in both environments,comparative analysis of the annual average oxygen concentration showed that the average inside the forest was 22.13%,while the value outside it was 21.39%.The annual average oxygen concentration inside the forest was 3.34%higher than that outside the forest.(2)Regarding the seasonal variation in oxygen content at both sites,the oxygen concentration inside the forest was consistently higher than that outside the forest in all four seasons.The oxygen concentrations inside the forest were 22.1%,21.9%,21.8%,and 21.5%in spring,summer,autumn,and winter,respectively,while outside the forest,they were 22.0%,21.8%,21.7%,and 21.4%for the same seasons,respectively.(3)The diurnal variation trends of oxygen concentration at both sites were similar throughout all four seasons,exhibiting a single-peak and double-trough curve pattern.The peak period occurred at 13:00 in spring,summer,and winter,and at 9:00 in autumn.The trough periods were observed at 7:00 and between 21:00 and 23:00 or at 5:00.展开更多
Highly efficient and non-precious catalysts are imperative for oxygen reduction reaction（ORR） to replace Pt/C. Anchoring efficient active species to carbon supports is a promising and scalable strategy. Here we synt...Highly efficient and non-precious catalysts are imperative for oxygen reduction reaction（ORR） to replace Pt/C. Anchoring efficient active species to carbon supports is a promising and scalable strategy. Here we synthesize Cu nanoparticles and noncrystalline CuNxCy species co-decorated ketjenblack（KB） carbon catalyst（denoted as Cu-N-KB-acid） by a facile and scalable method using copper sulfate, melamine, and KB as raw materials. An initial one-pot hydrothermal treatment is designed before pyrolysis process to achieve the good distribution of Cu and melamine on KB via a possible chelation effect. Owing to the synergistic effect of Cu and CuNxCy on KB, this composite catalyst displays excellent ORR catalytic activity in alkaline solution, which is comparable to the commercial 20% Pt/C. When used as a catalyst in a home-made Al-air battery, it shows a stable discharge voltage of 1.47 V at a discharge density of 50 mA cm-2, a little higher than that of Pt/C（1.45 V）.展开更多
Recent advances in the preparation and application of perovskite-type oxides as bifunctional electrocatalysts for oxygen reaction and oxygen evolution reaction in rechargeable metal-air batteries are presented in this...Recent advances in the preparation and application of perovskite-type oxides as bifunctional electrocatalysts for oxygen reaction and oxygen evolution reaction in rechargeable metal-air batteries are presented in this review.Various fabrication methods of these oxides are introduced in detail,and their advantages and disadvantages are analyzed.Different preparation methods adopted have great influence on the morphologies and physicochemical properties of perovskite-type oxides.As a bifunctional electrocatalyst,perovskite-type oxides are widely used in rechargeable metal-air batteries.The relationship between the preparation methods and the performances of oxygen/air electrodes are summarized.This work is concentrated on the structural stability,the phase compositions,and catalytic performance of perovskite-type oxides in oxygen/air electrodes.The main problems existing in the practical application of perovskite-type oxides as bifunctional electrocatalysts are pointed out and possible research directions in the future are recommended.展开更多
Air flow control is one of the most important control methods for maintaining the stability and reliability of a fuel cell system, which can avoid oxygen starvation or oxygen saturation. The oxygen excess ratio （OER...Air flow control is one of the most important control methods for maintaining the stability and reliability of a fuel cell system, which can avoid oxygen starvation or oxygen saturation. The oxygen excess ratio （OER） is often used to indicate the air flow condition. Based on a fuel cell system model for vehicles, OER performance was analyzed for different stack currents and temperatures in this paper, and the results show that the optimal OER was affected weakly by the stack temperature. In order to ensure the system working in optimal OER, a control scheme that includes an optimal OER regulator and a fuzzy control was proposed. According to the stack current, a reference value of air flow rate was obtained with the optimal OER regulator and then the air compressor motor voltage was controlled with the fuzzy controller to adjust the air flow rate provided by the air compressor. Simulation results show that the control method has good dynamic and static characteristics.展开更多
The mechanisms of oxygen-reduced air flooding(ORAF)and the explosion limit and the corrosion control approaches were studied based on the pilots of oxygen-reduced air flooding(ORAF)in the Dagang,Changqing and Daqing o...The mechanisms of oxygen-reduced air flooding(ORAF)and the explosion limit and the corrosion control approaches were studied based on the pilots of oxygen-reduced air flooding(ORAF)in the Dagang,Changqing and Daqing oil fields in China.On the foundation of indoor investigations and pilots,the explosion limits,oxygen reduction limits and corrosion control approaches were clarified.When the temperature of reservoir is equal to and higher than 120℃,there is a violent reaction between oxygen and crude oil,that means the effect of low temperature oxidation would be fully taken use of to enhance oil recovery by air flooding directly;nitrogen dominated immiscible flooding with oxygen-reduced air should be applied in cases where reservoir temperature is below 120℃ with little oxygen consumption and little heat generated.The oxygen-reduced air flooding is suitable for 3 types of reservoirs:low permeability reservoir,water flooding development reservoir of high water-cut and high temperature and high salinity reservoir.In the process of development,in order to ensure safety,the oxygen reduction limits should be controlled fewer than 10%,while oxygen-reduced air can obviously reduce the corrosion rate of pipes;The surface pipelines and injection wells don’t need to consider about oxygen corrosion with no water,special materials and structure of pipe or corrosion inhibitor can be applied to the surface pipelines and injection wellbores with water.Air/oxygen-reduced air is a low-cost displacement medium and it could be applied in many special conditions of low permeability reservoir for energy supplement,huff and puff and displacement,that means oxygen-reduced air flooding has become the most potential strategic technology in 20 years.展开更多
Two experimental techniques have been used to quantify the atomic oxygen density in the case of hot air plasma generated by a microwave （MW） resonant cavity. The latter operates at a frequency of 2.45 GHz inside a c...Two experimental techniques have been used to quantify the atomic oxygen density in the case of hot air plasma generated by a microwave （MW） resonant cavity. The latter operates at a frequency of 2.45 GHz inside a cell of gas conditioning at a pressure of 600 mbar, an injected air flow of 12 L/min and an input MW power of 1 kW. The first technique is based on the standard two photon absorption laser induced fluorescence （TALIF） using xenon for calibration but applied for the first time in the present post discharge hot air plasma column having a temperature of about 4500 K near the axis of the nozzle. The second diagnostic technique is an actinometry method based on optical emission spectroscopy （OES）. In this case, we compared the spectra intensities of a specific atomic oxygen line （844 nm） and the closest wavelength xenon line （823 nm）. The two lines need to be collected under absolutely the same spectroscopic parameters. The xenon emission is due to the addition of a small proportion of xenon （1% Xe） of this chemically inert gas inside the air while a further small quantity of H2 （2~） is also added in the mixture in order to collect OH（A- X） and NH（A-X） spectra without noise. The latter molecular spectra are required to estimate gas and excitation temperatures. Optical emission spectroscopy measurements, at for instance the position z=12 mm on the axis plasma column that leads to a gas measured temperature equal to 3500 K, an excitation temperature of about 9500 K and an atomic oxygen density 2.09× 1017＋ 0.2×1017 cm-3. This is in very good agreement with the TALIF measurement, which is equal to 2.0×101T cm-3.展开更多
Nitrogen-doped carbon materials encapsulating 3 d transition metals are promising alternatives to replace noble metal Pt catalysts for efficiently catalyzing the oxygen reduction reaction(ORR). Herein, we use cobalt s...Nitrogen-doped carbon materials encapsulating 3 d transition metals are promising alternatives to replace noble metal Pt catalysts for efficiently catalyzing the oxygen reduction reaction(ORR). Herein, we use cobalt substituted perfluorosulfonic acid/polytetrafluoroethylene copolymer and dicyandiamide as the pyrolysis precursor to synthesize nitrogen-doped carbon nanotube(N–CNT) encapsulating cobalt nanoparticles hybrid material. The carbon layers and specific surface area of N–CNT have a critical role to the ORR performance due to the exposed active sites, determined by the mass ratio of the two precursors. The optimum hybrid material exhibits high ORR activity and stability, as well as excellent performance and durability in zinc–air battery.展开更多
Systemic air embolism through a bronchovenous fistu-la(BVF) has been described in patients undergoing positive-pressure ventilation. However, no report has mentioned the potential risks of systemic air embolism throug...Systemic air embolism through a bronchovenous fistu-la(BVF) has been described in patients undergoing positive-pressure ventilation. However, no report has mentioned the potential risks of systemic air embolism through a BVF in patients undergoing extracorporeal membrane oxygenation(ECMO). Positive-pressure ventilation and ECMO support in patients with lung injury can increase the risk of systemic air embolism through a BVF. Increased alveolar pressure, decreased pulmonary venous pressure, and anticoagulation are thought to be the factors that contribute to this complication. Here, we present a case of systemic air embolism in a patient with ECMO and mechanical ventilator support.展开更多
The aluminum-air battery is considered to be an attractive candidate as a power source for electric vehicles(EVs) because of its high theoretical energy density(8100 Wh kg^(-1)), which is significantly greater than th...The aluminum-air battery is considered to be an attractive candidate as a power source for electric vehicles(EVs) because of its high theoretical energy density(8100 Wh kg^(-1)), which is significantly greater than that of the state-of-the-art lithium-ion batteries(LIBs). However,some technical and scientific problems preventing the large-scale development of Al-air batteries have not yet to be resolved. In this review, we present the fundamentals, challenges and the recent advances in Al-air battery technology from aluminum anode, air cathode and electrocatalysts to electrolytes and inhibitors. Firstly, the alloying of aluminum with transition metal elements is reviewed and shown to reduce the selfcorrosion of Al and improve battery performance. Additionally for the cathode, extensive studies of electrocatalytic materials for oxygen reduction/evolution including Pt and Pt alloys, nonprecious metal catalysts, and carbonaceous materials at the air cathode are highlighted.Moreover, for the electrolyte, the application of aqueous and nonaqueous electrolytes in Al-air batteries are discussed. Meanwhile, the addition of inhibitors to the electrolyte to enhance electrochemical performance is also explored. Finally, the challenges and future research directions are proposed for the further development of Al-air batteries.展开更多
Fuel tank inerting technologies are able to reduce the fire risk by injection of inert gas into the ullage or fuel, the former called ullage washing and the latter fuel scrubbing. The Green On-Board Inert Gas Generati...Fuel tank inerting technologies are able to reduce the fire risk by injection of inert gas into the ullage or fuel, the former called ullage washing and the latter fuel scrubbing. The Green On-Board Inert Gas Generation System（GOBIGGS） is a novel technology based on flameless catalytic combustion, and owning to its simple structure and high inerting efficiency, it has received a lot of attentions. The inert gas in the GOBIGGS is mainly comprised of CO2, N2, and O2（hereinafter, Mixed Inert Gas（MIG））, while that in the On-Board Inert Gas Generation System（OBIGGS）, which is one of the most widely used fuel tank inerting technologies, is NitrogenEnriched Air（NEA）. The solubility of CO2 is nearly 20 times higher than that of N2 in jet fuels,so the inerting capability and performance are definitely disparate if the inert gas is selected as NEA or MIG. An inerting test bench was constructed to compare the inerting capabilities between NEA and MIG. Experimental results reveal that, if ullage washing is adopted, the variations of oxygen concentrations on the ullage and in the fuel are nearly identical no matter the inert gas is NEA or MIG. However, the ullage and dissolved oxygen concentrations of MIG scrubbing are always higher than those of NEA scrubbing.展开更多
Rational design of low-cost, highly electrocatalytic activity, and stable bifunctional electrocatalysts for oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) has been a great significant for metal–air...Rational design of low-cost, highly electrocatalytic activity, and stable bifunctional electrocatalysts for oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) has been a great significant for metal–air batteries. Herein, an efficient bifunctional electrocatalyst based on hollow cobalt oxide nanoparticles embedded in nitrogen-doped carbon nanosheets(Co/N-Pg) is fabricated for Zn–air batteries. A lowcost biomass peach gum, consisting of carbon, oxygen, and hydrogen without other heteroatoms, was used as carbon source to form carbon matrix hosting hollow cobalt oxide nanoparticles. Meanwhile, the melamine was applied as nitrogen source and template precursor, which can convert to carbon-based template graphitic carbon nitride by polycondensation process. Owing to the unique structure and synergistic effect between hollow cobalt oxide nanoparticles and Co-N-C species, the proposal Co/N-Pg catalyst displays not only prominent bifunctional electrocatalytic activities for ORR and OER, but also excellent durability. Remarkably, the assembled Zn–air battery with Co/N-Pg air electrode exhibited a low discharge-charge voltage gap(0.81 V at 50 mA cm^-2) and high peak power density(119 mW cm^-2) with long-term cycling stability. This work presents an effective approach for engineering transition metal oxides and nitrogen modified carbon nanosheets to boost the performance of bifunctional electrocatalysts for Zn–air battery.展开更多
基金Supported by Science and Technology Project of Beijing Municipal Administration Center of Parks (ZX2019ZX2017).
文摘This study was conducted to investigate the air oxygen content inside and outside a Phyllostachys edulis forest in Qishan Forest Park throughout all four seasons.(1)Regarding the overall annual variation in oxygen content in both environments,comparative analysis of the annual average oxygen concentration showed that the average inside the forest was 22.13%,while the value outside it was 21.39%.The annual average oxygen concentration inside the forest was 3.34%higher than that outside the forest.(2)Regarding the seasonal variation in oxygen content at both sites,the oxygen concentration inside the forest was consistently higher than that outside the forest in all four seasons.The oxygen concentrations inside the forest were 22.1%,21.9%,21.8%,and 21.5%in spring,summer,autumn,and winter,respectively,while outside the forest,they were 22.0%,21.8%,21.7%,and 21.4%for the same seasons,respectively.(3)The diurnal variation trends of oxygen concentration at both sites were similar throughout all four seasons,exhibiting a single-peak and double-trough curve pattern.The peak period occurred at 13:00 in spring,summer,and winter,and at 9:00 in autumn.The trough periods were observed at 7:00 and between 21:00 and 23:00 or at 5:00.
基金supported by the National Natural Science Foundation of China (nos. 21671200 and 21571189)Fujian Provincial Natural Science Foundation of China (no. 2015J01072)+1 种基金the Hunan Provincial Science and Technology Plan Project, China (no. 2016TP1007)Innovation-Driven Project of Central South University (no. 2016CXS009)
文摘Highly efficient and non-precious catalysts are imperative for oxygen reduction reaction（ORR） to replace Pt/C. Anchoring efficient active species to carbon supports is a promising and scalable strategy. Here we synthesize Cu nanoparticles and noncrystalline CuNxCy species co-decorated ketjenblack（KB） carbon catalyst（denoted as Cu-N-KB-acid） by a facile and scalable method using copper sulfate, melamine, and KB as raw materials. An initial one-pot hydrothermal treatment is designed before pyrolysis process to achieve the good distribution of Cu and melamine on KB via a possible chelation effect. Owing to the synergistic effect of Cu and CuNxCy on KB, this composite catalyst displays excellent ORR catalytic activity in alkaline solution, which is comparable to the commercial 20% Pt/C. When used as a catalyst in a home-made Al-air battery, it shows a stable discharge voltage of 1.47 V at a discharge density of 50 mA cm-2, a little higher than that of Pt/C（1.45 V）.
基金Projects(51504212,21573184,51703061)supported by the National Natural Science Foundation of ChinaProject(2018J01521)supported by the Natural Science Foundation of Fujian Province,ChinaProject(fma2017202)supported by the Open Fund of Fujian Provincial Key Laboratory of Functional Materials and Applications(Xiamen University of Technology),China
文摘Recent advances in the preparation and application of perovskite-type oxides as bifunctional electrocatalysts for oxygen reaction and oxygen evolution reaction in rechargeable metal-air batteries are presented in this review.Various fabrication methods of these oxides are introduced in detail,and their advantages and disadvantages are analyzed.Different preparation methods adopted have great influence on the morphologies and physicochemical properties of perovskite-type oxides.As a bifunctional electrocatalyst,perovskite-type oxides are widely used in rechargeable metal-air batteries.The relationship between the preparation methods and the performances of oxygen/air electrodes are summarized.This work is concentrated on the structural stability,the phase compositions,and catalytic performance of perovskite-type oxides in oxygen/air electrodes.The main problems existing in the practical application of perovskite-type oxides as bifunctional electrocatalysts are pointed out and possible research directions in the future are recommended.
基金supported by the National Natural Science Foundation of China (No. 51177138)the Research Fund for the Doctoral Program of High Education of China (No.20100184110015)Sichuan Province International Technology Cooperation and Exchange Program (No. 2012HH0007)
文摘Air flow control is one of the most important control methods for maintaining the stability and reliability of a fuel cell system, which can avoid oxygen starvation or oxygen saturation. The oxygen excess ratio （OER） is often used to indicate the air flow condition. Based on a fuel cell system model for vehicles, OER performance was analyzed for different stack currents and temperatures in this paper, and the results show that the optimal OER was affected weakly by the stack temperature. In order to ensure the system working in optimal OER, a control scheme that includes an optimal OER regulator and a fuzzy control was proposed. According to the stack current, a reference value of air flow rate was obtained with the optimal OER regulator and then the air compressor motor voltage was controlled with the fuzzy controller to adjust the air flow rate provided by the air compressor. Simulation results show that the control method has good dynamic and static characteristics.
文摘The mechanisms of oxygen-reduced air flooding(ORAF)and the explosion limit and the corrosion control approaches were studied based on the pilots of oxygen-reduced air flooding(ORAF)in the Dagang,Changqing and Daqing oil fields in China.On the foundation of indoor investigations and pilots,the explosion limits,oxygen reduction limits and corrosion control approaches were clarified.When the temperature of reservoir is equal to and higher than 120℃,there is a violent reaction between oxygen and crude oil,that means the effect of low temperature oxidation would be fully taken use of to enhance oil recovery by air flooding directly;nitrogen dominated immiscible flooding with oxygen-reduced air should be applied in cases where reservoir temperature is below 120℃ with little oxygen consumption and little heat generated.The oxygen-reduced air flooding is suitable for 3 types of reservoirs:low permeability reservoir,water flooding development reservoir of high water-cut and high temperature and high salinity reservoir.In the process of development,in order to ensure safety,the oxygen reduction limits should be controlled fewer than 10%,while oxygen-reduced air can obviously reduce the corrosion rate of pipes;The surface pipelines and injection wells don’t need to consider about oxygen corrosion with no water,special materials and structure of pipe or corrosion inhibitor can be applied to the surface pipelines and injection wellbores with water.Air/oxygen-reduced air is a low-cost displacement medium and it could be applied in many special conditions of low permeability reservoir for energy supplement,huff and puff and displacement,that means oxygen-reduced air flooding has become the most potential strategic technology in 20 years.
文摘Two experimental techniques have been used to quantify the atomic oxygen density in the case of hot air plasma generated by a microwave （MW） resonant cavity. The latter operates at a frequency of 2.45 GHz inside a cell of gas conditioning at a pressure of 600 mbar, an injected air flow of 12 L/min and an input MW power of 1 kW. The first technique is based on the standard two photon absorption laser induced fluorescence （TALIF） using xenon for calibration but applied for the first time in the present post discharge hot air plasma column having a temperature of about 4500 K near the axis of the nozzle. The second diagnostic technique is an actinometry method based on optical emission spectroscopy （OES）. In this case, we compared the spectra intensities of a specific atomic oxygen line （844 nm） and the closest wavelength xenon line （823 nm）. The two lines need to be collected under absolutely the same spectroscopic parameters. The xenon emission is due to the addition of a small proportion of xenon （1% Xe） of this chemically inert gas inside the air while a further small quantity of H2 （2~） is also added in the mixture in order to collect OH（A- X） and NH（A-X） spectra without noise. The latter molecular spectra are required to estimate gas and excitation temperatures. Optical emission spectroscopy measurements, at for instance the position z=12 mm on the axis plasma column that leads to a gas measured temperature equal to 3500 K, an excitation temperature of about 9500 K and an atomic oxygen density 2.09× 1017＋ 0.2×1017 cm-3. This is in very good agreement with the TALIF measurement, which is equal to 2.0×101T cm-3.
基金financial support from the Ministry of Science and Technology of China(Grants 2016YFB0600901 and 2013CB933100)the National Natural Science Foundation of China(Grants 21573222 and 91545202)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB17020200)financial support from CAS Youth Innovation Promotion(Grant No.2015145)
文摘Nitrogen-doped carbon materials encapsulating 3 d transition metals are promising alternatives to replace noble metal Pt catalysts for efficiently catalyzing the oxygen reduction reaction(ORR). Herein, we use cobalt substituted perfluorosulfonic acid/polytetrafluoroethylene copolymer and dicyandiamide as the pyrolysis precursor to synthesize nitrogen-doped carbon nanotube(N–CNT) encapsulating cobalt nanoparticles hybrid material. The carbon layers and specific surface area of N–CNT have a critical role to the ORR performance due to the exposed active sites, determined by the mass ratio of the two precursors. The optimum hybrid material exhibits high ORR activity and stability, as well as excellent performance and durability in zinc–air battery.
基金Supported by 2014 Research Grant from Kangwon National University
文摘Systemic air embolism through a bronchovenous fistu-la(BVF) has been described in patients undergoing positive-pressure ventilation. However, no report has mentioned the potential risks of systemic air embolism through a BVF in patients undergoing extracorporeal membrane oxygenation(ECMO). Positive-pressure ventilation and ECMO support in patients with lung injury can increase the risk of systemic air embolism through a BVF. Increased alveolar pressure, decreased pulmonary venous pressure, and anticoagulation are thought to be the factors that contribute to this complication. Here, we present a case of systemic air embolism in a patient with ECMO and mechanical ventilator support.
基金supported by Natural Sciences and Engineering Research Council of Canada (NSERC)Canada Research Chair (CRC) Program+1 种基金National Nature Science Foundation of China (No.51474255)Open-End Fund for the Graduate Student Research Innovation Project of Hunan Province (No. 150140008)
文摘The aluminum-air battery is considered to be an attractive candidate as a power source for electric vehicles(EVs) because of its high theoretical energy density(8100 Wh kg^(-1)), which is significantly greater than that of the state-of-the-art lithium-ion batteries(LIBs). However,some technical and scientific problems preventing the large-scale development of Al-air batteries have not yet to be resolved. In this review, we present the fundamentals, challenges and the recent advances in Al-air battery technology from aluminum anode, air cathode and electrocatalysts to electrolytes and inhibitors. Firstly, the alloying of aluminum with transition metal elements is reviewed and shown to reduce the selfcorrosion of Al and improve battery performance. Additionally for the cathode, extensive studies of electrocatalytic materials for oxygen reduction/evolution including Pt and Pt alloys, nonprecious metal catalysts, and carbonaceous materials at the air cathode are highlighted.Moreover, for the electrolyte, the application of aqueous and nonaqueous electrolytes in Al-air batteries are discussed. Meanwhile, the addition of inhibitors to the electrolyte to enhance electrochemical performance is also explored. Finally, the challenges and future research directions are proposed for the further development of Al-air batteries.
基金supported by Funding of Jiangsu Innovation Program for Graduate Education of China (No.KYLX15_0231)Postgraduate Research & Practice Innovation Program of Jiangsu Province of China (No.KYCX17_0279)+1 种基金the Fundamental Research Funds for the Central Universities,Aviation Industry Corporation of China Technology Innovation Fund for Fundamental Research (No.2014D60931R)Funding of Ministry of Industry and Information Technology for Civil Aircraft
文摘Fuel tank inerting technologies are able to reduce the fire risk by injection of inert gas into the ullage or fuel, the former called ullage washing and the latter fuel scrubbing. The Green On-Board Inert Gas Generation System（GOBIGGS） is a novel technology based on flameless catalytic combustion, and owning to its simple structure and high inerting efficiency, it has received a lot of attentions. The inert gas in the GOBIGGS is mainly comprised of CO2, N2, and O2（hereinafter, Mixed Inert Gas（MIG））, while that in the On-Board Inert Gas Generation System（OBIGGS）, which is one of the most widely used fuel tank inerting technologies, is NitrogenEnriched Air（NEA）. The solubility of CO2 is nearly 20 times higher than that of N2 in jet fuels,so the inerting capability and performance are definitely disparate if the inert gas is selected as NEA or MIG. An inerting test bench was constructed to compare the inerting capabilities between NEA and MIG. Experimental results reveal that, if ullage washing is adopted, the variations of oxygen concentrations on the ullage and in the fuel are nearly identical no matter the inert gas is NEA or MIG. However, the ullage and dissolved oxygen concentrations of MIG scrubbing are always higher than those of NEA scrubbing.
基金financially supported by the National Natural Science Foundation of China (Nos. 21506081, 21705058, 21676126)the Provincial Natural Science Foundation of Jiangsu (Nos. BK20170524, BK20160492)+2 种基金China Postdoctoral Science Foundation (No. 2018T110450)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education InstitutionsThe financial support from an ARC Discovery Project (No. DP180102003)
文摘Rational design of low-cost, highly electrocatalytic activity, and stable bifunctional electrocatalysts for oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) has been a great significant for metal–air batteries. Herein, an efficient bifunctional electrocatalyst based on hollow cobalt oxide nanoparticles embedded in nitrogen-doped carbon nanosheets(Co/N-Pg) is fabricated for Zn–air batteries. A lowcost biomass peach gum, consisting of carbon, oxygen, and hydrogen without other heteroatoms, was used as carbon source to form carbon matrix hosting hollow cobalt oxide nanoparticles. Meanwhile, the melamine was applied as nitrogen source and template precursor, which can convert to carbon-based template graphitic carbon nitride by polycondensation process. Owing to the unique structure and synergistic effect between hollow cobalt oxide nanoparticles and Co-N-C species, the proposal Co/N-Pg catalyst displays not only prominent bifunctional electrocatalytic activities for ORR and OER, but also excellent durability. Remarkably, the assembled Zn–air battery with Co/N-Pg air electrode exhibited a low discharge-charge voltage gap(0.81 V at 50 mA cm^-2) and high peak power density(119 mW cm^-2) with long-term cycling stability. This work presents an effective approach for engineering transition metal oxides and nitrogen modified carbon nanosheets to boost the performance of bifunctional electrocatalysts for Zn–air battery.
