蒲公英花球状NiCO_(2)O_(4)/碳量子点双功能电催化剂的制备与性能

Preparation and Performance of Dandelion-shaped NiCo_(2)O_(4)/Carbon Quantum Dot Composites for Bifunctional Electrocatalysts

本研究利用镍钴氧化物(NiCO_(2)O_(4), NCO)和碳量子点(CQDs),通过水热法和煅烧处理制备出蒲公英花球结构的NiCO_(2)O_(4)-CQDs (NCO-CQDs)复合双功能电催化剂。通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)和X射线衍射仪(XRD)表征NCO-CQDs的微观结构,NCO-CQDs复合材料是由NCO相互堆叠形成的纳米棒和CQDs颗粒形成的蒲公英花球状复合材料。为了增加NCO-CQDs复合材料的氧空位从而提高电化学性能,通过在空气中煅烧的NCO-CQDs复合材料,得到优异的性能,在氧还原反应(ORR)中,所研究的NiCO_(2)O_(4)-CQDs-air催化剂展现了0.752 V的半波电位,且在经历20 000 s的稳定性测试后,其电流保持率高达92.2%,这一结果显著优于传统的Pt/C催化剂(68.6%),突显出其卓越的稳定性。在氧析出反应(OER)方面,以10 mA/cm^(2)的电流密度进行评估时,该催化剂的电位为1.874 V,Tafel斜率为100.9 mV/dec,这些性能指标均优于Pt/C催化剂(电位2.007 V,Tafel斜率312.9 mV/dec),并且与IrO_(2)催化剂的性能相当(电位1.794 V,Tafel斜率44.8 mV/dec)。

In this paper,using nickel cobalt oxide(NiCo_(2)O_(4),NCO)and carbon quantum dots(CQDs),dandelion-shaped structures of NiCo_(2)O_(4)-CQDs(NCO-CQDs)composite bifunctional catalysts were prepared by the hydrothermal method and calcination.The microstructures of NCO-CQDs composites were studied by scanning electron microscopy(SEM),transmission electron microscopy(TEM)and X-ray diffraction(XRD).NCO-CQDs composites were composed of the stacked NCO nanorods and CQDs particles formed into dandelion flower spherical composite.In order to increase the oxygen vacancy of NCO-CQDs composite and improve the electrochemical performances,the NCO-CQDs composites were calcined in air to obtain excellent performances.The half wave potential reached 0.752 V during ORR.After 20000 seconds,NCO-CQDs composites maintained 92.2%of its initial current density,higher than that of Pt/C sample(68.6%),showing excellent stability.For OER,under the current density test of 10 mA/cm^(2),NCO-CQDs-air sample presented an onset potential of 1.874 V and a Tafel slope of 100.9 mV/dec,which is superior to Pt/C(2.007 V,312.9 mV/dec)and equivalent to IrO_(2)(1.794 V,44.8 mV/dec).