| Autor: |
Sanad MF; Department of Chemistry and Biochemistry, The University of Texas at El Paso, 500 W. University Avenue, El Paso, Texas 79968, United States.; Department of Environmental Sciences and Engineering, The University of Texas at El Paso, 500 W. University Avenue, El Paso, Texas 79968, United States., Chava VSN; Department of Chemistry and Biochemistry, The University of Texas at El Paso, 500 W. University Avenue, El Paso, Texas 79968, United States., Shalan AE; BCMaterials-Basque Center for Materials, Applications and Nanostructures, Martina Casiano, UPV/EHU Science Park, Barrio Sarriena s/n, Leioa 48940, Spain.; Central Metallurgical Research and Development Institute (CMRDI), P.O. Box 87, Helwan, Cairo 11421, Egypt., Enriquez LG; Department of Chemistry and Biochemistry, The University of Texas at El Paso, 500 W. University Avenue, El Paso, Texas 79968, United States., Zheng T; Department of Automotive Engineering, Clemson University, 4 Research Drive, Greenville, South Carolina 29607, United States., Pilla S; Department of Automotive Engineering, Clemson University, 4 Research Drive, Greenville, South Carolina 29607, United States.; Clemson Composites Centre, Clemson University, Greenville, South Carolina 29607, United States.; Department of Materials Science and Engineering, Clemson University, Clemson, South Carolina 29602, United States.; Department of Mechanical Engineering, Clemson University, Clemson, South Carolina 29602, United States., Sreenivasan ST; Department of Chemistry and Biochemistry, The University of Texas at El Paso, 500 W. University Avenue, El Paso, Texas 79968, United States. |
| Abstrakt: |
Facile electron transport and intimate electronic contact at the catalyst-electrode interface are critical for the ideal performance of electrochemical devices such as glucose biofuel cells and biosensors. Here, through a comprehensive experimental-theoretical exploration, we demonstrate that engineering of interfacial properties, including interfacial electron dynamics, electron affinity, electrode-catalyst-adsorbate electrical synergy, and electrocatalytically active surface area, can lead to highly efficient graphene-based electrochemical devices. We selected two closely related but electronically and surface chemically different functionalized graphene analogues-graphene acid (GA) and reduced graphene oxide (rGO)-as the model graphenic platforms. Our studies reveal that compared to rGO, GA is a superior bifunctional catalyst with high oxygen reduction reaction (an onset potential of 0.8 V) and good glucose oxidation activities. Spectroscopic and electrochemical analysis of GA and rGO indicated that the higher carboxylic acid content on GA increases its overall electron affinity and coupled with improved conductivity and band alignment, which leads to GA's better electrochemical performance. The formulation of a heterostructure between GA and samarium oxide (Sm 2 O 3 ) nanoparticles led to augmented conductivity (lower charge-transfer resistance) and glucose binding affinity, resulting in a further enhanced glucose oxidation activity. The interdimensional Sm 2 O 3 /GA heterostructure, leveraging their enhanced glucose oxidation capacity, exhibited excellent nonenzymatic amperometric glucose sensing performance, with a detection limit of 107 nM and a sensitivity of 20.8 μA/μM. Further, a nonenzymatic, membrane-free glucose biofuel cell (with Sm 2 O 3 /GA heterostructure as anode and GA as biocathode) produced a power density of 3.2 μW·cm -2 (in PBS spiked with 3 mM glucose), which can function as self-powered glucose sensors with 70 nM limit of detection. The study establishes the potential of interfacial engineering of GA to engage it as a highly tunable substrate for a broad range of electrochemical applications, especially in future self-powered biosensors. |
