Hydrogenated Boride-Assisted Gram-Scale Production of Platinum-Palladium Alloy Nanoparticles on Carbon Black for PEMFC Cathodes: A Study from a Practical Standpoint.

Abstract

Platinum-palladium (PtPd) alloy catalysts with high durability are viable substituents to commercial Pt/C for proton exchange membrane fuel cells (PEMFCs). Herein, a facile approach for gram-scale preparation of PtxPd100-x alloy nanoparticles on carbon black is developed. The optimized Pt54Pd46/B-C catalyst shows a mass activity (MA) of 0.549 A mgPt-1 and a specific activity (SA) of 0.463 mA cm-2 at the rotating disk electrode (RDE) level, which are 3.4 and 1.9 times those of commercial Pt/C, respectively. In H2/O2 and H2/air PEMFCs, the membrane electrode assembly (MEA) with Pt54Pd46/B-C achieves peak power densities of 2.33 and 1.04 W cm-2, respectively, and shows negligible performance degradation after 100 h of running in H2/O2 conditions. Moreover, the MA of MEA with Pt54Pd46/B-C in H2/O2 PEMFC reaches 0.978 A mgPt+Pd-1 beyond the 2020 target of the Department of Energy (DOE) of 0.44 A mgPt-1. After 30k cyclic voltammetry cycles in PEMFC, the MA loss and cell voltage loss of MEA with Pt54Pd46/B-C are well within the DOE 2020 target. Density functional theory calculations reveal that the PtPd(111) surface can weaken the adsorption of *OOH and *OH compared to the Pt(111) surface, indicating that Pt54Pd46/B-C is more energetically favorable for the oxygen reduction reaction (ORR) than commercial Pt/C. This study offers a new approach for batch preparation of PtPd alloy-based catalysts for PEMFCs.