Turning to the reaction order with respect to molecular hydrogen (Fig. ), at low pH values of 6 to 10, accessed in phosphate and later also borate and carbonate buffer, the reaction order is approx. constant at 0.0-0.2, with a large uncertainty due to the necessary MT-correction. Further elaboration on the use of pH-buffers in the determination of the HOR/HER is undertaken in a separate publication. At higher pH, 𝑚 𝐻 2 rises continuously from a value of ~0.3 at pH 10.5 to a value of ~0.6 at pH 14. While sodium and potassium containing electrolytes behave similarly, lithium containing electrolytes show a stark deviation as their reaction order appears to hover around 0.5 for over 4 pH units.