Comparison of Co/Zn-NC@PPy-۸۰۰ and Commercial Pt/C as the Cathode Electrocatalyst of Fuel Cell-based Breath Ethanol Sensor

Alkaline direct ethanol fuel cells (DEFC), which convert the chemical energy stored in ethanol directly into electricity, are one of the most promising energy-conversion devices for portable, mobile and stationary power applications as well as highly sensitive devices for ethanol sensing. Exploring highly active, stable, and inexpensive electrocatalysts for the oxygen reduction reaction (ORR) is pivotal in developing sensitive sensors. In this research, synthesized Co/Zn-NC@PPy-۸۰۰ and commercial Pt/C are used as ORR catalyst. In the SEM image (Fig. ۱), Co/Zn-NC@PPy-۸۰۰ NPs on the polypyrrole sheets are formed N-doped nanosheet-like carbon. The fuel cell performance curves are shown in Fig. ۲. Two identical cells are made using the same anodes and Co/Zn-NC@PPy-۸۰۰ and commercial ۱۰ wt.% Pt/C as the ORR electrocatalyst for cathode fabrication. The anion-exchange membrane (A۲۰۱ Tokuyama), with a thickness of ۲۸ μm is used as electrolyte. ۲ M of ethanol in a ۲ M KOH solution which was stabled in ۱۲ ml tank was fed to the anode side and cathode was performed under air breathing and O۲ bleeding modes. In fig. ۲a, polarization and power density curves are displayed and explaining the fuel cell has better performance when it equipped with Co/Zn-NC@PPy-۸۰۰ in compare with ۱۰ wt. % Pt/C as cathode catalyst. Furthermore, using non-noble synthesized cathode catalyst, the I-V behavior shows no significant change under O۲ and air breathing modes. The cathode polarizations are depicted in fig. ۲b. It can be seen that Co/Zn-NC@PPy-۸۰۰ is more active than ۱۰ wt. % Pt/C for ORR in both O۲ and air breathing modes which means Co/Zn-NC@PPy-۸۰۰ has better tolerance against ethanol crossover in compare with ۱۰ wt. % Pt/C. In addition, according to the Fig. ۲c, the cell polarization curve in Co/Zn-NC@PPy-۸۰۰ case is only depends on anode polarization and oxygen partial pressure in oxidant flow has no effect on fuel cell response.