Clean and O-(2√2×√2)R45°Cu(100) surfaces were prepared to study the impact of surface oxygen on the activation of methane dissociation.Auger electron spectroscopy,low energy electron diffraction,infrared reflection absorption spectroscopy,scanning tunneling microscope,and a quadrupole mass-spectrometer for temperature programmed desorption were used to explore the behavior of CH_(4) on the two surfaces.The dissociative adsorption of CH_(4) was observed on oxygen-pre-covered Cu(100) but not on the clean surface indicating surface oxygen promotes the dissociation of the C-H bond.This study can be a reference for the conversion of methane into other high-value-added products with high efficiency and low energy consumption.
锌离子电容器(ZICs)具有能量密度高、倍率性能好、循环寿命长、成本低等优点,近年来得到了广泛的研究。在碳基阴极表面引入氧官能团是提高水系ZICs电容性能的有效策略。然而,氧官能团的存在是否有利于提高乙醇(EtOH)基ZICs的电容性能,目前还没有被深入研究。本文采用硝酸氧化和进一步热处理的方法对阴极活性炭表面的氧官能团进行了优化。在ZnCl2/EtOH电解液中,优化后的样品在电流密度为1 A g^(−1)时比电容达到195 F g^(−1),比未改性的样品(125 F g^(−1))提高了56%。同时,ZICs也表现出良好的循环稳定性,在3 A g^(−1)下的稳定循环次数超过16000次,并且保持100%的库仑效率。这是因为氧官能团,特别是羧基和酯基(―COO)的存在,为Zn2+氧化还原反应提供了丰富的电化学活性位点。因此,本研究通过优化氧官能团增强了炭阴极的电容性能,并为EtOH基ZICs的商业应用提供了研究基础。
