Kotp Amna A, Abdelwahab Abdalla, Farghali Ahmed A, Rouby Waleed M A El, Enaiet Allah Abeer
Materials Science and Nanotechnology Department, Faculty of Postgraduate Studies for Advanced Sciences, Beni-Suef University Beni-Suef 62511 Egypt.
Faculty of Science, Galala University Sokhna Suez 43511 Egypt.
RSC Adv. 2023 Sep 20;13(40):27934-27945. doi: 10.1039/d3ra05105f. eCollection 2023 Sep 18.
Efficient electrocatalysts, with high tolerance to methanol oxidation, good stability, and acceptable cost are the main requisites for promising direct methanol fuel cell (DMFC) electrode materials. This target can be achieved by the integration of different active materials with unique structures. In this work, a cobalt metal-organic framework (Co-MOF) flower structure was prepared by a hydrothermal method, and then a simple ultrasonication method was employed to anchor carbon nanotubes (CNTs) in between the MOF flower petals and fabricate a Co-MOF/CNT hybrid composite. Different ratios of CNTs were used in the composite preparations, namely 25, 50, and 75 wt% of the composite. The nanocomposites were entirely investigated using different characterization techniques, such as XRD, FTIR, SEM, TEM, and XPS. Comparative electrochemical measurements confirmed that due to the integration of highly conductive CNTs with the porous active fascinating structure of Co-MOF, Co-MOF/50% CNTs exhibited improved electrocatalytic activity with a current density of 35 mA cm at a potential of 0.335 V and a scan rate of 50 mV s. The excellent electrochemical activity and stability could be due to the synergy between Co-MOF and the CNTs that conferred adequate active sites for methanol electro-oxidation and a lower equivalent series resistance, as revealed from the electrochemical impedance spectroscopy study. This study opens a new avenue to decrease the utilization of platinum and increase the methanol oxidation activity using low-cost catalysts.
高效的电催化剂对甲醇氧化具有高耐受性、良好的稳定性且成本可接受，这是有望用于直接甲醇燃料电池（DMFC）电极材料的主要要求。通过将具有独特结构的不同活性材料整合在一起可以实现这一目标。在这项工作中，采用水热法制备了钴金属有机框架（Co-MOF）花状结构，然后采用简单的超声处理方法将碳纳米管（CNT）锚定在MOF花瓣之间，制备了Co-MOF/CNT杂化复合材料。在复合材料制备中使用了不同比例的CNT，即复合材料的25%、50%和75%（重量）。使用不同的表征技术，如XRD、FTIR、SEM、TEM和XPS对纳米复合材料进行了全面研究。对比电化学测量证实，由于高导电性的CNT与Co-MOF的多孔活性迷人结构相结合，Co-MOF/50% CNT在0.335 V的电位和50 mV s的扫描速率下表现出改善的电催化活性，电流密度为35 mA cm。从电化学阻抗谱研究中可以看出，优异的电化学活性和稳定性可能归因于Co-MOF和CNT之间的协同作用，这种协同作用为甲醇电氧化提供了足够的活性位点并降低了等效串联电阻。这项研究开辟了一条新途径，即使用低成本催化剂来减少铂的用量并提高甲醇氧化活性。
