ElSayed Nada Gamal, Farghali Ahmed A, El Rouby Waleed M A, Hmamm Mai F M
Materials Science and Nanotechnology Department, Faculty of Postgraduate Studies for Advanced Sciences (PSAS), Beni-Suef University 62511 Beni-Suef Egypt.
Renewable Energy Science and Engineering Department, Faculty of Postgraduate Studies for Advanced Science, Beni-Suef University 62511 Beni-Suef Egypt
Nanoscale Adv. 2024 Aug 20;6(20):5133-44. doi: 10.1039/d4na00549j.
The higher energy density and lesser toxicity of ethanol compared to methanol make it an ideal combustible renewable energy source in fuel cells. Finding suitable cost-effective electrocatalysts that can oxidize ethanol in ethanol-based fuel cells is a major challenge. With their high catalytic activity and stability in alkaline media, transition metal-based catalysts are ideal candidates for alkaline direct ethanol fuel cells. Nickel-based nanomaterials and composites exhibit high electrocatalytic activity, which makes them predominant candidates for the electrochemical oxidation of ethanol. In this study, the electrocatalytic activity of a nickel oxide flower-like structure was explored. Forming a nanocomposite of NiO in combination with carbon nanotubes (CNTs), NiO/CNTs, as a substrate led to an increase in the stability of the electrocatalyst in alkaline media. Furthermore, the electrocatalytic activity of the NiO/CNT nanocomposite was greatly enhanced by decorating the surface with different ratios of silver (Ag). Ag/NiO/CNT composites with different Ag ratios, namely, 25% and 50% by weight, were studied. The Ag 25%/NiO/CNT weight ratio showed a maximum ethanol conversion. At an ethanol concentration of 300 mM, the electrochemical oxidation current density was found to be 57.1 ± 0.2 mA cm for the 25% by weight Ag ratio, with a five-fold increase in the current density (compared to NiO/CNTs (10 ± 0.34 mA cm)). Furthermore, the nanocomposite synthesized here (Ag 25%/NiO/CNTs) showed a significantly higher energy conversion (current per ethanol concentration) rate compared to other reported NiO-based catalysts. These results open real opportunities for designing high efficiency ethanol fuel cell catalysts.
与甲醇相比，乙醇具有更高的能量密度和更低的毒性，这使其成为燃料电池中理想的可燃可再生能源。寻找能够在基于乙醇的燃料电池中氧化乙醇的合适的具有成本效益的电催化剂是一项重大挑战。过渡金属基催化剂因其在碱性介质中具有高催化活性和稳定性，是碱性直接乙醇燃料电池的理想候选者。镍基纳米材料和复合材料表现出高电催化活性，这使其成为乙醇电化学氧化的主要候选者。在本研究中，探索了氧化镍花状结构的电催化活性。将NiO与碳纳米管（CNTs）形成纳米复合材料，即NiO/CNTs，作为底物可提高电催化剂在碱性介质中的稳定性。此外，通过用不同比例的银（Ag）修饰表面，NiO/CNT纳米复合材料的电催化活性大大增强。研究了具有不同Ag比例（即25%和50%重量）的Ag/NiO/CNT复合材料。25%重量比的Ag/NiO/CNT显示出最大的乙醇转化率。在乙醇浓度为300 mM时，发现25%重量比的Ag的电化学氧化电流密度为57.1±0.2 mA/cm²，电流密度增加了五倍（与NiO/CNTs（10±0.34 mA/cm²）相比）。此外，与其他报道的基于NiO的催化剂相比，此处合成的纳米复合材料（25%Ag/NiO/CNTs）显示出显著更高的能量转换（每乙醇浓度的电流）速率。这些结果为设计高效乙醇燃料电池催化剂提供了切实的机会。
