Using pH Indicator To Demonstrate Supercapacitor Reactions

• Emily Traver ^[1] ; Jamie E. Stark ^[1] ; Gianna Aleman Milán ^[1] ; Heather A. Andreas ^[1]
  1. [1] Dalhousie University

     Dalhousie University

     Canadá

     
• Localización: Journal of chemical education, ISSN 0021-9584, Vol. 96, Nº 8, 2019, págs. 1778-1781
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • In this supplement to our second-year supercapacitor lab (Bringing Real-World Energy-Storage Research into a Second-Year Physical-Chemistry Lab Using a MnO2-Based Supercapacitor. J. Chem. Educ.2018, 95 (11), 2028–2033), we incorporate a color indicator as indirect evidence for the manganese oxide’s pseudocapacitive reaction (MnO2 + H+ + e– ⇌ MnOOH). Using the evidence of pH changes (the methyl red goes from light yellow to red during an oxidative potential hold), students can make the link between oxidation state changes and the applied potential of the electrochemical experiment. Herein, we optimize the indicator concentration and electrochemical parameters to ensure the color changes are evident. Optimal responses arise when 15 μM methyl red is coupled with a 2 min, 0.8 V potentiostatic hold.