Negative resistance (NR) phenomena due to the tunneling and inter -valley scattering effects in semiconductors have been applied in microwave power sources. An NR phenomenon due to the transition between under- and over-potentially deposited hydrogen (UPD H and OPD H) at noble metal/acidic and alkaline aqueous solution interfaces has not been studied based on the Frumkin adsorption isotherms, which are not easily determined using conventional methods. We determine the Frumkin adsorption isotherms of UPD H and OPD H for the hydrogen evolution reaction (HER) at a poly-Rh/0.1 M LiOH aqueous solution interface using the phase-shift method and electrochemical impedance spectroscopy. The NR phenomenon due to the transition effect of UPD H and OPD H is analyzed using the Frumkin adsorption isotherms and square wave voltammetry. The NR characteristic due to the transition effect of UPD H and OPD H at the poly-Rh interface is similar to that due to the two valley model theory or the inter-valley scattering effect in III-V compound semiconductors. The NR phenomenon due to the transition between UPD H and OPD H is a unique feature of the poly-Rh interface. We hope that the NR phenomenon for the HER at the poly-Rh interface will be studied for its potential and application as a new power source. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.