Non-precious metal catalysts (NPMCs), particularly the type based on carbon-supported FeN x functionalities (Fe-N-C) are a very promising material for replacing the rare and costly platinum-based catalysts in polymer electrolyte membrane fuel cells (PEMFCs). Evaluation of these materials is most often carried out, like for Pt-based catalysts, in dilute perchloric acid by assuming its non-adsorbing nature on the active sites. The assumption is however not true. In this work, a typical Fe-N-C catalyst was first synthesized by high-pressure pyrolysis in the presence of carbon support and thoroughly characterized in terms of morphology, structure and active site distribution.The subsequent electrochemical characterization of the catalyst shows strong adsorption and poisoning effect of, in addition to the known Cl -, perchloric anions on the oxygen reduction reaction (ORR) activity. On the contrary phosphate anions exhibit negligible poisoning effect on the catalyst activity. At a potential of 0.8 V vs. RHE, the ORR activity of the catalysts is found to decrease in the order of H 3 PO 4 (8.6 mA mg -1 ) > HClO 4 (3.1 mA mg -1 ) > HCl (0.69 mA mg -1 ). The results suggest potential applications of NPMC in high-temperature PEMFCs based on phosphoric acid doped polymer membranes, where high loading platinum catalysts are currently used. As demonstrated in the low current density range of high-temperature PEMFCs, the catalyst shows a comparable performance to the Pt/C catalysts.

M a n g a n e s e o x i d e -m o d i f i e d g r a p h e n e nanosheet-supported silver nanocatalyst (Ag-MnO x /G) was prepared via two-step chemical and electrochemical deposition. Surface characterization of the prepared AgMnO x /G catalyst was performed by X-ray photoelectron spectroscopy, scanning electron microscopy, as well as Xray fluorescence techniques, and the electrocatalytic activity toward the oxygen reduction reaction (ORR) in alkaline media was studied using cyclic voltammetry and the rotating disk electrode (RDE) method. The onset potential of the ORR of the prepared catalyst material shifted positive about 40 mV, and the half-wave potential 20 mV compared to those of the bulk Ag electrode. After 1000 potential cycles between 0.05 and 1.1 V for accelerated aging tests, high stability of the Ag-MnO x /G catalyst in the ORR was observed with the half-wave potential of the ORR shifting negatively only about 0.04 V. RDE studies displayed unconditional improvement of electrochemical activity and long-term durability for the Ag-MnO x /G composite material.