Tailoring the Durability of Carbon-Coated Pd Catalysts Towards Hydrogen Oxidation Reaction (HOR) in Alkaline Media

For the hydrogen oxidation reaction (HOR), platinum group metal (PGM) catalysts are still norm, and their large initial catalytic activity is counterbalanced by uncertain durability in alkaline environments: harsh degradations proceed, like detachment agglomeration of metallic nanoparticles from carbon support, as witnessed dedicated accelerated stress tests (AST). Herein, a strategy to increase such catalysts’ provided, using layers surrounding Pd-based carbon-supported nanoparticles. The robustness catalysts, baring 0.5- or 0.7-nm-thick cap over Pd nanoparticles, evaluated AST combined with several pre/post-test characterization techniques: identical location transmission electron microscopy (IL-TEM), ex situ X-ray photoelectron spectroscopy (XPS) inductively coupled plasma mass spectrometry (ICP-MS). layer protection limits nanoparticles’ agglomeration, detachment, leaching, improving long-term catalyst HOR-like operation. Thicker lead higher materials lower degradation rate (larger performance stability) upon AST, compared thinner layers. In addition, carbon-capped enable maintain better required Pd/PdO state surface that essential for fast HOR, resulting superior intrinsic HOR versus unprotected Pd/C. Overall, this work demonstrates activity-durability relationship can be tuned catalysts.