Effect of Formic Acid on Fuel Cell Performance for Automobile Applications

Single-cell tests and exhaust gas analyses were conducted to understand the reaction behavior of formic acid (HCOOH) and its effect on fuel cell performance, as specified in the hydrogen quality standard for fuel cell vehicles. HCOOH decreased the voltage with increasing concentration, but the effect was smaller than that of carbon monoxide and performance was recovered by stopping the HCOOH supply. Exhaust gas analysis during the fuel cell operation and electrochemical measurements with HCOOH adsorbed on the electrocatalyst showed that the HCOOH supplied to the anode should permeate the electrolyte membrane and be oxidized at the cathode to produce carbon dioxide. Verification tests in the hydrogen circulation system that is typically used in actual fuel cell vehicles confirmed that the effect of HCOOH did not appear at current densities up to 2.0 A cm −2 and concentrations up to 5 ppm.