Pt-IrOx catalysts immobilized on defective carbon for efficient reversal tolerant anode in proton exchange membrane fuel cells

Abstract

Proton exchange membrane fuel cells (PEMFCs) can utilize hydrogen with high efficiency without emitting pollutants. For the dissemination of the PEMFCs in the automotive industry, the stable automobile operation under transient conditions is important. Under fuel starvation, carbon oxidation can take place at the anode, reversing the cell voltage. By covering the carbon support with finely dispersed IrOx, the contact of carbon with water can be avoided minimizing carbon oxidation, instead, water is electrolyzed on the IrOx. Here, we deposited IrOx nanoparticles on the Pt/C with highly defective carbon. Contrary to the common belief that defective carbon is vulnerable to corrosion, the catalyst could endure better in the absence of H-2, with the longest time of 44 h until reaching the cell voltage of -2.5 V. When the IrOx was immobilized on more defective carbon, the electrochemical surface area was higher, and the surface IrOx was more oxidic, resulting in higher oxygen evolution reaction (OER) activity and better CO tolerance. The carbon defects remaining after IrOx deposition were further removed by oxidizing the catalyst. The effect of the oxidation temperature was also examined. (C) 2021 Elsevier Inc. All rights reserved.