GETTING STARTED ELECTROCHEMICAL GUIDE

How to measure potential of reference electrodes vs. RHE

1. Introduction
2. Instrumentation
3. RHE Preparation using H2G1
4. Potential measurement vs. RHE using H2G1

1. Introduction

⋅ In electrochemistry, a specific potential is applied upon a working electrode in order to let a specific reaction occur.
The potential of the working electrode should be always exactly specified.

⋅ Reference electrodes are benchmark for applied potential to working electrodes.
Accuracy and stability are required for reference electrodes.

⋅ In actual application, the potential of reference electrodes might be shifted according to spent hours.
That is the reason we have to measure the potential of reference electrodes against Reversible Hydrogen Electrode (RHE) and calibrate the potential on a daily basis.

⋅ Here, we will introduce how to set up RHEK Reversible Hydrogen Electrode Kit.
In addition to that, by using the representative reference electrode, RE-1BP Reference electrode (Ag/AgCl), we will show the measurement procedure of potential measurements (calibration) of reference electrodes.

2. Instrumentation

2.1 Device, Accessories, Reagents

⋅ Device
H2G1 Portable Hydrogen Generator
Model 2325 Bi-Potentiostat
TB-1 Thermostatic Chamber

⋅ Accessories
RHEK Reversible Hydrogen Electrode Kit
Sample holder dia 9.0 mm
RE-1BP Reference electrode (Ag/AgCl)
SVC-2 Voltammetry cell
RE-PV Preservative vial for reference electrode
Cell holder for 20 mL vial
Pipette
Distilled water

⋅ Reagents
1.2 M HCl solution
3.0 M NaCl solution

2.2 Pretreatment

1. Fill 3 M NaCl solution into the Sample holder dia 9.0 mm using the pipette.

2. Then immerse the Sample holder dia 9.0 mm in distilled water.

3. Put the RE-1BP Reference electrode (Ag/AgCl) into the RE-PV Preservative vial for reference electrode which is filled with 3 M NaCl solution.
Movie: How to use

This method prevents the Sample holder to dry.

The inner solution of the RE-1BP Reference electrode (Ag/AgCl) is 3 M NaCl solution. This preservation method helps to stabilize the potential of the RE-1BP Reference electrode (Ag/AgCl).

3. RHE Preparation using H2G1

3.1 Setup(Configuration)

Configuration

Note
⋅ Take care of air bubbles.
⋅ Make sure to fit the O-ring into the hole of the Telron cap of SVC-2.

⋅Device
H2G1 Portable Hydrogen Generator

⋅Accessories
RHEK Reversible Hydrogen Electrode Kit

(content)
RHE Reversible hydrogen electrode
Tubing clamp
Silicone tube (10 cm) x 3
O-ring
Female lure fitting
Disposable syringe

SVC-2 Voltammetry cell
(content)
Sample vial (20 ml) x 7
Platinum counter electrode 5.7 cm
Teflon cap for SVC-2
Purging tube 30 cm

Cell holder for 20 mL vial

⋅Reagents
1.2 M HCl solution

Content of the Reversible hydrogen elctrode kit

3.2 Operation of H2G1 for hydrogen generation

1. Fill 1.2 M HCl solution about half of the Sample vial (20 ml) of the SVC-2 Voltammetry cell.

2. Set the Teflon cap for SVC-2 into the Sample vial (20 ml), then set them into the Cell holder for 20 mL vial.

3. Set the RHE Reversible hydrogen electrode into the hole of the Teflon cap for SVC-2 and fix it with the O-ring.

Fill 1.2 M HCl solution into half of the Sample vial (20 ml).

The Cell holder helps stabilize the Voltammetry cell

4. Set the Platinum counter electrode 5.7 cm, into the Teflon cap for SVC-2.

5. Push the Disposable syringe to the top and connect the Disposable syringe with the Silicone tube (10 cm).

6. Pull the Disposable syringe to fill the 1.2 M HCl solution until the Silicone tube (10 cm), and nip the Silicone tube (10 cm) in the middle of the solution by the Tubing clamp. Take care of air bubbles.

The Platinum counter electrode 5.7 cm is included in the contents of the SVC-2 Voltammetry cell

Push the Disposable syringe to the top so that you can pull up the solution.

7. Take out the Disposable syringe.

8. Connect the black cable to the RHE Reversible hydrogen electrode and the red cable to the Platinum counter electrode 5.7 cm respectively.

9. Turn on the H2G1 Portable Hydrogen Generator and press and hold the button for about 2 second and set the electrolysis time to 5 minutes.

Connect the black cable to the RHE and the red cable to the Platinum counter electrode 5.7 cm.

Press the button for about 2 second and set the electrolysis time at 5 minutes.

10. Press the button and start electrolysis.

11. After 5 minutes, the set up is completed.

After 5 minutes the electrolysis is completed.

4. Potential measurement vs. RHE using H2G1

4.1 Setup(Configuration)

Configuration

⋅ Device
H2G1 Portable Hydrogen Generator
TB-1 Thermostatic Chamber

⋅ Accessories
RHEK Reversible Hydrogen Electrode Kit

(content)
RHE Reversible hydrogen electrode
Tubing clamp
Silicone tube (10 cm) x 3
O-ring
Female lure fitting
Disposable syringe

SVC-2 Voltammetry cell
(content)
Sample vial (20 ml) x 7
Platinum counter electrode 5.7 cm
Teflon cap for SVC-2
Purging tube 30 cm

RE-PV Preservative vial for reference electrode

Cell holder for 20 mL vial

⋅ Reagents
1.2 M HCl solution
3 M NaCl solution

Note
⋅ Take care of air bubbles.
⋅ Make sure to fit the O-ring into the hole of the Teflon cap of SVC-2.

4.2 Operation of H2G1 for RE-1BP potential measurement vs. RHE

1. Pull out the RE-1BP Reference electrode (Ag/AgCl) from the RE-PV Preservative vial for reference electrode.
Then set the RE-1BP Reference electrode (Ag/AgCl) into the Sample holder dia 9.0 mm in which 3 M NaCl solution is filled.

2. Set the Sample holder dia 9.0 mm in the Teflon cap for SVC-2 and fit the O-ring into the hole.

Set the RE-1BP Reference electrode (Ag/AgCl) into the Smaple holder dia 9.0 mm

3. Keep connecting the black cable to the RHE Reversible hydrogen electrode and connect the white cable to the RE-1BP Reference electrode (Ag/AgCl).

4. Push and hold the button, then potential measurement will start.

4.3 Use TB-1 to measure potential at 25℃

1. Plug in the TB-1 Thermostatic Chamber and set the temperature at 25℃.

2. Put the black cable and the white cable through the upper hole of TB-1 and seal the hole.

Put the black cable and the white cable through the upper hole of TB-1 and seal the hole.

3. Put the setup SVC-2 Voltammetry cell into the TB-1, then connect the black cable to the RHE Reversible hydrogen electrode and the white cable to the RE-1BP Reference electrode (Ag/AgCl) respectively.Then close the TB-1.

4. Push and hold the button, then potential measurement will start.