Control of carboxyl group content in the organic ligands of Co-based MOFs to enhance glucose electrocatalytic oxidation: Towards fuel cell and sensor applications

A catalyst for both a DGFC and a NEGS was prepared. • The direct glucose fuel cell achieves a peak power output of 443.62 μW. • The sensor detection limit is as low as 0.17 μM. • Ligand carboxyl group significantly affects the performance of the catalyst. • Enhancing the GOR performance of Co-based MOFs. The glucose oxidation reaction is the primary reaction occurring at the anode of glucose fuel cells and sensors, and the choice of anode material plays a decisive role in determining their overall performance. This study investigates the influence of the number of carboxyl groups on the aromatic ring of Co-based metal–organic framework (MOF) ligands on the physicochemical properties of the catalyst. The results show that the B2C-1.5 catalyst, with terephthalic acid as the organic ligand and Co as the inorganic metal connector, exhibits the highest ion diffusion rate, peak power, and lowest glucose detection limit, with high crystallinity and large specific surface area. Notably, the direct glucose fuel cells (DGFC) based on this catalyst achieved a peak power of 443.62 μW/cm 2 ; the sensor demonstrated rapid response to glucose oxidation with a detection limit as low as 0.17 μM. Furthermore, this work indicates that within the range where the ligand coordination environment becomes increasingly complex, the increase in the carboxyl content on the aromatic ring leads to a decrease in the orderliness of the crystal structure, an uneven morphology, a decrease in charge transfer and ion diffusion efficiency, a reduction in the content of Co 3+ active centers and ECSA, resulting in a gradual decline in catalytic performance. These findings provide valuable insights for the rational selection of ligands in the design and development of advanced MOF-based glucose oxidation catalysts. Download: Download high-res image (251KB) Download: Download full-size image