Notes from 7/7/20

Bintao training on temperature-dependent RuO2 CV


Step 0: Calibrate the temperature of the water

  • Using temperature probe (connected to the back of water temp controller), check the temperature in the cell electrolyte is at the expected temperature


  1. Cleaning the temperature dependent cell
  • Night before experiment, soak cell overnight in LiOH (15-20 pellets)
  • On experiment day, heat the cell until the electrolyte boils; then dispose of the LiOH
  • Wash your gloves in DI water to get rid of the powder on the gloves
    • Wash the cell many times in DI water
    • Wash the cell stoppers in DI water
  1. Preparing the 0.1 M LiOH solution
    • As you prepare the solution, plug the cell with the stoppers
    • Pour in the measured LiOH powder into the inner cell; pour in the measured DI water into the inner cell
    • Cover the graduated cylinder used to measure the water with parafilm after using
  2. Purge the cell in Ar
    • Wash the RuO2 working electrode, Ag/AgCl reference electrode, the Pt counter electrode, and purging tube with DI water before inserting into the cell
      • Note that RuO2 WE is inserted in the largest cell hole with the large stopper
    • Purge the cell with Ar for 15 min
  3. Take the CV of RuO2 using small potential window (parameters below)

    • CV doesn’t look clean (not symmetrical about 0 current) – resolved by cleaning RuO2 in DI water more
      • For more intense cleaning, you can let the RuO2 sit in 0.1 KOH for 15 min
  1. Calibrate to RHE – purge with H2 to see potential difference between RHE and Ag/AgCl (not done today)
  2. Set temperature of cell to 5 deg C
    • Water temp controller has two black tubes
      • Tube with teal tape = water out, inserted into lower cell tube hole
      • Second tube = water in, inserted into the upper cell tube hole

  • Set the water temp controller to 5 deg C using the middle button “T” and then press “OK”, water will flow into outer jacket of the cell

  • Now wait for 45 min – 1 hour for the cell to cool down
  • Take out the RuO2, wash it in DI, and soak it in DI
    • When you’re ready to insert the RuO2 back into the cell, wash it under DI and dry with N2 gas
  1. RuO2 CV in Ar purge
    • Purge the cell with Ar and use same CV parameters as above
  2. OER CV (parameters below)
    • Want the adsorption peaks to be << OER peak

  1. Impedance measurement
    • Use the value resistance value at the intersection of the semicircle and exponential for the Rs value

  1. In preparation for high-temp experiments prepare and pipette 1 M NaOH solution for the Hg/HgO electrode