Influence Factors on Induced Potential of Reduced Graphene Oxide-based Microfluidic Voltage Generations

In this paper, reduced graphene oxide (rGO)-based microfluidic voltage generations were fabricated with the suspensions at different rGO concentration. Different values of the induced potential of these rGO-based microfluidic voltage generations were generated at various volume flow rate of NaCl solution. Based on Nernst-Planck equation the quantitative relationship between the Na+ ion concentration in the diffusion layer upon the surface of the working electrode and induced potential of the microfluidic voltage generation was established. With the values of induced potential corresponding to different volume flow rates of the NaCl solution, the effect of the volume flow rate on both mass transporting of Na+ ions from the solution upon the rGO membranes and the concentration of the Na+ ion adsorbed on the surface of working electrode, and further the induced potential of the rGO-based microfluidic voltage generation had been researched. Besides, by quantitatively characterizing the surface morphology of the rGO membrane with the surface texture aspect ratio (Str) and maxium height (Sz), the relationship among the rGO concentration of the suspension, the surface morphology of the rGO membrane, the concentration of the Na+ ion adsorbed on the surface of the working electrode and the induced potential of the microfluidic voltage generation had been established. At volume flow rate 50 mu L/min of the NaCl solution and rGO concentration 1.0 mg/mL of the suspension the rGO-based microfluidic voltage generation can generate an optimal induced potential -343 mV. These results benefit not only the fabrication and performance optimizations of other carbon-based microfluidic voltage generations, but also the behavior improvements of the microfluidic channel based photo-degradation reactors, ion sensing devices and electrochemical glucose sensors.