Consumable carbon anodes are used in the electrowinning of aluminium by the Hall-Heroult process. Emissions of CO2 may be eliminated by introducing an inert oxygen evolving anode, which however will require a higher a...Consumable carbon anodes are used in the electrowinning of aluminium by the Hall-Heroult process. Emissions of CO2 may be eliminated by introducing an inert oxygen evolving anode, which however will require a higher anode potential. An alternative approach is to use a natural gas or hydrogen gas anode to reduce the CO2 emissions and lower the anode potential. Preliminary laboratory experiments were carried out in an alternative molten salt electrolyte consisting of CaCl2-CaO-NaCl at 680℃ Porous anodes of platinum and tin oxide were tested during electrolysis at constant current. The behaviour of inert anode candidate materials such as tin oxide and nickel ferrite were also studied.展开更多
Pb?Ag?PbO2 composite anodes with different mass fractions(1%,2%,3%,4%and 5%)ofβ-PbO2 were prepared by powder-pressed(PP)method.The galvanostatic polarization curves,Tafel curves and anodic polarization curves were te...Pb?Ag?PbO2 composite anodes with different mass fractions(1%,2%,3%,4%and 5%)ofβ-PbO2 were prepared by powder-pressed(PP)method.The galvanostatic polarization curves,Tafel curves and anodic polarization curves were tested in sulfuric acid solution.The morphologies and phase compositions of the anodic layers formed after galvanostatic polarization were investigated by using scanning electron microscope(SEM)and X-ray diffractometer(XRD),respectively.The results showed thatβ-PbO2 can improve the electrocatalytic activity of anodic oxide.The anode containing 3%β-PbO2 had the lowest overpotential of oxygen evolution reaction(OER)and the best corrosion resistance.The morphologies of the anode surfaces were gradually transformed from regular crystals to amorphous ones as the content ofβ-PbO2 increased in anodes.展开更多
The demanding all-in-one electrocatalyst system for oxygen reduction reaction(ORR), oxygen evolution reaction(OER) and hydrogen evolution reaction(HER) in zinc-air batteries or water splitting requires elaborate mater...The demanding all-in-one electrocatalyst system for oxygen reduction reaction(ORR), oxygen evolution reaction(OER) and hydrogen evolution reaction(HER) in zinc-air batteries or water splitting requires elaborate material manufacturing, which is usually complicated and time-consuming.Efficient interface engineering between MXene and highly active electrocatalytic species(CoS_(2)) is, herein, achieved by an in situ hydrothermal growth and facile sulfurization process.The CoS_(2)@MXene electrocatalyst is composed by one-dimensional CoS_(2) nanowires and two-dimensional MXene nanosheets, which lead to a hierarchical structure(large specific surface area and abundant active sites), a spatial electron redistribution(high intrinsic activity), and high anchoring strength(superior performance stability). Therefore, the electrocatalyst achieves enhanced catalytic activity and longtime stability for ORR(a half-wave potential of 0.80 V), OER(an overpotential of 270 mV at 10 mA cm^(-2), i.e., η10= 270 mV)and HER(η10= 175 mV). Furthermore, the asymmetry water splitting system based on the CoS_(2)@MXene composites delivers a low overall voltage of 1.63 V at 10 mA cm^(-2). The solidstate zinc-air batteries using CoS_(2)@MXene as the air cathode display a small charge-discharge voltage gap(0.53 V at1 mA cm^(-2)) and superior stability(60 circles and 20-h continuous test). The energy interconversion between the chemical energy and electricity can be achieved by a self-powered system via integrating the water splitting system and quasisolid-state zinc-air batteries. Supported by in situ Raman analyses, the formation of cobalt oxyhydroxide species provides the active sites for water oxidation. This study paves apromising avenue for the design and application of multifunctional nanocatalysts.展开更多
文摘Consumable carbon anodes are used in the electrowinning of aluminium by the Hall-Heroult process. Emissions of CO2 may be eliminated by introducing an inert oxygen evolving anode, which however will require a higher anode potential. An alternative approach is to use a natural gas or hydrogen gas anode to reduce the CO2 emissions and lower the anode potential. Preliminary laboratory experiments were carried out in an alternative molten salt electrolyte consisting of CaCl2-CaO-NaCl at 680℃ Porous anodes of platinum and tin oxide were tested during electrolysis at constant current. The behaviour of inert anode candidate materials such as tin oxide and nickel ferrite were also studied.
基金Project(2017YFB0305401)supported by the National Key R&D Program of ChinaProjects(51874369,51474245,51871249)supported by the National Natural Science Foundation of China+1 种基金Project(2018JJ3659)supported by the Natural Science Foundation of Hunan Province,ChinaProject(2018RS3007)supported by Huxiang Young Talents Plan,China
文摘Pb?Ag?PbO2 composite anodes with different mass fractions(1%,2%,3%,4%and 5%)ofβ-PbO2 were prepared by powder-pressed(PP)method.The galvanostatic polarization curves,Tafel curves and anodic polarization curves were tested in sulfuric acid solution.The morphologies and phase compositions of the anodic layers formed after galvanostatic polarization were investigated by using scanning electron microscope(SEM)and X-ray diffractometer(XRD),respectively.The results showed thatβ-PbO2 can improve the electrocatalytic activity of anodic oxide.The anode containing 3%β-PbO2 had the lowest overpotential of oxygen evolution reaction(OER)and the best corrosion resistance.The morphologies of the anode surfaces were gradually transformed from regular crystals to amorphous ones as the content ofβ-PbO2 increased in anodes.
基金supported by the National Natural Science Foundation of China (51871119 and 51901100)the High-Level Entrepreneurial and Innovative Talents Program of Jiangsu Province,Jiangsu Provincial Funds for Natural Science Foundation (BK20170793 and BK20180015)+2 种基金the Six Talent Peak Project of Jiangsu Province (2018-XCL-033)China Postdoctoral Science Foundation (2018M640481 and 2019T120426)the Foundation of Graduation Innovation Center in NUAA (kfjj20190609)。
文摘The demanding all-in-one electrocatalyst system for oxygen reduction reaction(ORR), oxygen evolution reaction(OER) and hydrogen evolution reaction(HER) in zinc-air batteries or water splitting requires elaborate material manufacturing, which is usually complicated and time-consuming.Efficient interface engineering between MXene and highly active electrocatalytic species(CoS_(2)) is, herein, achieved by an in situ hydrothermal growth and facile sulfurization process.The CoS_(2)@MXene electrocatalyst is composed by one-dimensional CoS_(2) nanowires and two-dimensional MXene nanosheets, which lead to a hierarchical structure(large specific surface area and abundant active sites), a spatial electron redistribution(high intrinsic activity), and high anchoring strength(superior performance stability). Therefore, the electrocatalyst achieves enhanced catalytic activity and longtime stability for ORR(a half-wave potential of 0.80 V), OER(an overpotential of 270 mV at 10 mA cm^(-2), i.e., η10= 270 mV)and HER(η10= 175 mV). Furthermore, the asymmetry water splitting system based on the CoS_(2)@MXene composites delivers a low overall voltage of 1.63 V at 10 mA cm^(-2). The solidstate zinc-air batteries using CoS_(2)@MXene as the air cathode display a small charge-discharge voltage gap(0.53 V at1 mA cm^(-2)) and superior stability(60 circles and 20-h continuous test). The energy interconversion between the chemical energy and electricity can be achieved by a self-powered system via integrating the water splitting system and quasisolid-state zinc-air batteries. Supported by in situ Raman analyses, the formation of cobalt oxyhydroxide species provides the active sites for water oxidation. This study paves apromising avenue for the design and application of multifunctional nanocatalysts.
