What is a reference electrode

The reference electrode is the electrode used as a reference for comparison when measuring various electrode potentials. The electrode to be measured and the reference electrode of the accurately known electrode potential value constitute a battery, and the electromotive force value of the battery can be measured to calculate the electrode potential of the measured electrode. The electrode reaction carried out on the reference electrode must be a single reversible reaction with stable electrode potential and good reproducibility. Usually, the slightly soluble salt electrode is used as the reference electrode, and the hydrogen electrode is only an ideal but not easy to realize reference electrode.

An electrode for reference comparison when measuring the electrode potential. Strictly speaking, the standard hydrogen electrode is only an ideal electrode and cannot be realized in practice. Therefore, in the actual electrode potential measurement, an electrode whose electrode potential is accurately known and is very stable is always used as the comparison electrode. By measuring the electromotive force of the battery composed of such electrodes and the measured electrode, the electrode potential of the measured electrode can be calculated.

The electrode reaction on the reference electrode must be a single reversible reaction, the exchange current density is large, the production is convenient, the reproducibility is good, and the electrode potential is stable. A refractory salt electrode is generally used as a reference electrode. The reference electrode should not be prone to polarization; if the current is too large and polarization occurs, the electrode potential should be able to recover to the original value quickly after power failure; when the temperature changes, the electrode potential hysteresis change should be small.