Fundamental understandings on the impacts induced by anions and cations on oxygen reduction reaction (ORR) are of great interest in designing more efficient catalysts and identifying reasons for discrepancies in activities measured in different protocols. In this study, the specific adsorption of F^-, Cl^-, ClO₄^-, CO₃^2-, SO₄^2-, Nafion ionomer, and citrate anions on Pt/C, Pd/C and transition metal, N co-doped carbon-based (Me-N-C) catalysts, and their effects on the ORR kinetics were systematically investigated. It was found that ClO₄^- had a negligible impact on the ORR activity of Pt/C possibly due to its weak adsorption. Nafion ionomers, on the other hand showed a significant poisoning effect on the bulk Pt electrode. Its impact on Pt/C, however is negligible even with a very high I/C ratio (1.33) in acidic solutions. The three catalysts showed different behaviors in alkaline solutions. The non-covalent interaction between hydrated cations and surface OH groups was found on Pt/C and had an obvious impact on the ORR kinetics. This non-covalent interaction, however was not observed on Pd/C, which showed the same ORR activity in all three electrolytes (LiOH, NaOH and KOH). The ORR activity of Me-N-C increased following the order of KOH < NaOH < LiOH. This trend is totally opposite to that of Pt/C. Self-dissociation of citrate anion was found to occur on both Pt/C and Pd/C in the H adsorption/desorption and double layer regions. For the first time, surface enhanced infrared absorption spectroscopy (SEIRAS) with the attenuated total reflection (ATR) technique was used to investigate the self-dissociation of citrate on Pt and Pd thin film electrodes. The break of carboxylic groups and carbon backbone were proposed as possible dissociation pathways for citrate. The adsorbed species have a negligible effect on ORR activity on Pt/C as they are removed by oxidation before 0.75 V. In contrast, their oxidation on Pd/C surfaces is not completed until 0.91 V, which causes a lower ORR activity observed in rotating disk electrode measurements.