CO tolerance and durability study of PtMe (Me = Ir or Pd) electrocatalysts for H_2-PEMFG application

摘要

In the present work, carbon supported PtMe (Me = Ir or Pd) electrocatalysts, with different atomic ratios (Pt/Me (20 wt%) = 3:1, 1:1, 1:3), are thoroughly investigated towards CO tolerance and durability, as anode and cathode for H-2-PEMFCs (hydrogen fed proton exchange membrane fuel cells) application. The electrocatalysts are prepared via a pulse-microwave assisted polyol synthesis method and their durability and electrocatalytic activity in presence and absence of CO are evaluated using the techniques of electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), linear sweep voltammetry (LSV), chronoamperometry (CA) and rotating disk electrode (RDE). For the investigation of CO tolerance a protocol is set that could be used by other research groups, since various procedures are reported in literature. It is found that Pd/C shows higher CO tolerance than Pt/C, while the PtPd3/C exhibits the highest CO tolerance ability, even after being exposed for 9 h at 400 ppm CO. Despite the fact that Pt3Ir/C shows higher CO tolerance ability than Pt/C, it cannot resist at such high CO concentrations for more than 6 h. Finally, it is found that PtIr/C and PtPd/C exhibit very good durability even after 5000 accelerated durability test (ADT) cycles, while Pt3Pd/C and PtPd/C present the highest mass activities (339.4 and 410 mA/mg(Pt) respectively at 0.9 V), which are 4 and 5 times higher than the one observed over commercial Pt/C (82.75 mA/mg(Pt)). (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.