这里,我们全面研究了甲醇在铜基催化剂上的电氧化,使我们能够构建第一个配备Cu阳极和无金属阴极的微流体燃料电池(μFC),该阴极可从甲醇中转换能量。我们应用了一个简单的,快,小规模,以及在室温下在稳态(ST)下合成铜基纳米颗粒的无表面活性剂策略,在机械搅拌(MS)下,或超声处理(美国)。Cu基样品的形态评估显示它们具有相同的纳米颗粒(NP)针状形式。元素映射组成谱表明,所有合成材料均获得了纯Cu或Cu氧化物。除了表面上有更多的Cu2O,样品US的Cu(OH)2比其他样品多,根据X射线衍射图和X射线光电子能谱。由于声波浴的局部加热,样品US的碳污染较少,这也提高了Cu表面的清洁度。通过电化学和光谱电化学测量研究了CuNP在碱性介质中甲醇电氧化的活性。动电位和恒电位实验显示在美国合成的NP具有较高的电流密度。原位FTIR实验表明,三种合成的NP材料通过甲酸盐将甲醇完全氧化为碳酸盐。最重要的是,所有途径都没有可检测到的CO,在高超电位下没有发现的中毒分子。使用US电极的反应路径在1.0V(vs.Ag/Ag/Cl),建议改进催化。在美国合成的NP的高活性归因于燃料的有效解离吸附,这是由于该位点的可用性和羟基的存在,该羟基的存在可以使吸附物从表面氧化。了解表面反应后,我们建立了一个混合介质μFC,在碱性介质中通过甲醇和在酸性介质中通过过硫酸钠进料。μFC配备有在超声浴改性碳纸中合成的CuNPs作为阳极,无金属碳纸作为阴极。由于甲醇电氧化的起始电位为0.45V,还原反应显示为0.90V,理论OCV为0.45V,它提供了自发的偶合氧化还原反应来产生电力。μFC在100μLmin-1时显示最大电流密度为0.56mAcm-2,峰值功率密度为26μWcm-2。这种无膜系统可以单独优化每个半电池,使得有可能构建具有无贵金属阳极和无金属阴极的燃料电池。
Here, we comprehensively investigated methanol electrooxidation on Cu-based catalysts, allowing us to build the first microfluidic fuel cell (μFC) equipped with a Cu anode and a metal-free cathode that converts energy from methanol. We applied a simple, fast, small-scale, and surfactant-free strategy for synthesizing Cu-based nanoparticles at room temperature in steady state (ST), under mechanical stirring (MS), or under ultrasonication (US). The morphology evaluation of the Cu-based samples reveals that they have the same nanoparticle (NP) needle-like form. The elemental mapping composition spectra revealed that pure Cu or Cu oxides were obtained for all synthesized materials. In addition to having more Cu2O on the surface, sample US had more Cu(OH)2 than the others, according to X-ray diffractograms and X-ray photoelectron spectroscopy. The sample US is less carbon-contaminated because of the local heating of the sonic bath, which also enhances the cleanliness of the Cu surface. The activity of the Cu NPs was investigated for methanol electrooxidation in an alkaline medium through electrochemical and spectroelectrochemical measurements. The potentiodynamic and potentiostatic experiments showed higher current densities for the NPs synthesized in the US. In situ FTIR experiments revealed that the three synthesized NP materials eletcrooxidize methanol completely to carbonate through formate. Most importantly, all pathways were led without detectable CO, a poisoning molecule not found at high overpotentials. The reaction path using the US electrode experienced an additional round of formate formation and conversion into carbonate (or CO2 in the thin layer) after 1.0 V (vs. Ag/Ag/Cl), suggesting improved catalysis. The high activity of NPs synthesized in the US is attributed to effective dissociative adsorption of the fuel due to the site\'s availability and the presence of hydroxyl groups that may fasten the oxidation of adsorbates from the surface. After understanding the surface reaction, we built a mixed-media μFC fed by methanol in alkaline medium and sodium persulfate in acidic medium. The μFC was equipped with Cu NPs synthesized in ultrasonic-bath-modified carbon paper as the anode and metal-free carbon paper as the cathode. Since the onset potential for methanol electrooxidation was 0.45 V and the reduction reaction revealed 0.90 V, the theoretical OCV is 0.45 V, which provides a spontaneous coupled redox reaction to produce power. The μFC displayed 0.56 mA cm-2 of maximum current density and 26 μW cm-2 of peak power density at 100 μL min-1. This membraneless system optimizes each half-cell individually, making it possible to build fuel cells with noble metal-free anodes and metal-free cathodes.