Pulsed electrochemical deposition of Pt NPs on polybenzimidazole-CNT hybrid electrode for high-temperature proton exchange membrane fuel cells

Abstract

Nitrogen-doped CNTs, directly grown on a carbon cloth (CNT/CC) hybrid with polybenzimidazole (PBI), are utilized as hybrid electrodes in high-temperature proton exchange membrane fuel cells (HT-PEMFCs). The use of a rotation holder for pulse electrodepositing Pt nanoparticles (NPs) on a CNT electrode is developed herein. The electrochemical surface area of the Pt NPs/PBI-CNTs is approximately 161 cm2 mg−1 and the grain size is around 8–9 nm. A comparative study of 0.09 mg cm−2 Pt NPs on a PBI–CNT (Pt/PBI–CNT) electrode and 0.8 mg cm−2 Pt NPs on PBI–carbon black (Pt/PBI–CB) for reducing oxygen at the cathode was carried out. In H2/O2 HT-PEMFC single cell tests, a low Pt-loaded (0.09 mg cm−2) Pt/PBI–CNT/CC electrode outperformed a high Pt-loaded (0.8 mg cm−2) Pt/PBI–CB/CC electrode with maximum power densities of 620 mW cm−2 and 468 mW cm−2, respectively, at 160 °C. The enhanced performance is attributed to the well-controlled grain size and Pt loading of Pt NPs on the PBI-CNT in the cathode, which provide the highly active catalyst and the good electrical conductivity carbon support.