Exploring liquid oxidants and metal-free cathode for enhanced performance in a reusable 3D-printed glycerol microfluidic fuel cell

Microfluidic fuel cells (mu FCs) offer a promising avenue for generating energy from glycerol, utilizing flow-through electrodes to enhance reactant utilization. However, the cathodic reaction must efficiently consume the electrons harvested at the anode side to unlock its full potential. Here, we explore the feasibility of employing liquid oxidants as an alternative to O2 reduction on metal-free carbon paper (CP) cathodes. We investigated the half-cell reactions and the energy conversion in a new reusable 3D-printed mu FC. Half-cell reactions predict spontaneous reactions by coupling glycerol electrooxidation in an alkaline medium with O2, Na2S2O8, and HClO from commercial bleach in an acidic medium. The mu FC printed using the stereolithography apparatus technique build microchannels to place the Pt/C/CP anode and CP cathodes. The glycerol/Na2S2O8 mu FC delivered a maximum of 32.4 mW cm-2, while glycerol/HClO mu FC displayed 55.9 mW cm-2. This research sheds light on the potential of liquid oxidants as effective alternatives to O2 reduction, presenting a pathway toward optimizing mu FCs and their practical applications in energy conversion from glycerol. image